WorldWideScience

Sample records for high mountain catchment

  1. A conceptual glacio-hydrological model for high mountainous catchments

    Directory of Open Access Journals (Sweden)

    B. Schaefli

    2005-01-01

    Full Text Available In high mountainous catchments, the spatial precipitation and therefore the overall water balance is generally difficult to estimate. The present paper describes the structure and calibration of a semi-lumped conceptual glacio-hydrological model for the joint simulation of daily discharge and annual glacier mass balance that represents a better integrator of the water balance. The model has been developed for climate change impact studies and has therefore a parsimonious structure; it requires three input times series - precipitation, temperature and potential evapotranspiration - and has 7 parameters to calibrate. A multi-signal approach considering daily discharge and - if available - annual glacier mass balance has been developed for the calibration of these parameters. The model has been calibrated for three different catchments in the Swiss Alps having glaciation rates between 37% and 52%. It simulates well the observed daily discharge, the hydrological regime and some basic glaciological features, such as the annual mass balance.

  2. Bed load size distribution and flow conditions in a high mountain catchment of Central Pyrenees

    OpenAIRE

    Martínez Castroviejo, Ricardo

    1990-01-01

    The bed load size distribution caused by different types of flow are compared in a high mountain catchment located in the upper Gallego river basin (Central Spanish’ Pyrenees). Three kinds of hydrologic events could be defined: those triggered by heavy autumn rainfalls, those originated by isolated summer rainstorms and those promoted by snowmelting. Each one is characterized by a peculiar bed load size distribution. Thus, it could be demonstrated that the coarser fractions, above 30 mm in di...

  3. A methodological comparison of catchment storages in mountainous catchments

    Science.gov (United States)

    Weiler, Markus; Staudinger, Maria; Stölzle, Michael; Seeger, Stefan; Seibert, Jan; Stahl, Kerstin

    2015-04-01

    storage characteristics are strongly dependent on the chosen method. However, the overall ranking of the catchments among the methods is quite similar, despite the derived catchment storage of one catchment may differ by one to two orders of magnitude. Surprisingly, the high elevation catchments generally show a much larger storage than most of the low elevation catchments. To investigate this surprising result further, we analyzed the effect of climate on the derived catchment storage in more detail, since an additional snow storage with the resulting melt period in spring may produce an large dynamic storage due to the concentrated input of water. We both used subsamples of discharge to divide the storage in snow or rain triggered storage and changed the climate input either to a rainfall or snowmelt dominated climate and compared the storage among the catchments based on a similar climate signal. We finally develop a framework for assessing and comparing catchment storages among catchments in different climates, geologies and with different physiographic characteristics. These analyses also provided more insights into the larger storage in mountainous catchments and its importance to catchments functions.

  4. Improved baseflow characterization in mountainous catchments

    Science.gov (United States)

    Stoelzle, Michael; Stahl, Kerstin; Schuetz, Tobias; Weiler, Markus; Seibert, Jan; Tallaksen, Lena M.

    2015-04-01

    Knowledge of the baseflow regime is crucial for managing river ecosystems during low flow periods. Then aquatic conditions, water supply or streamflow forecast highly depend on the sustainability, magnitude, timing or rate of change of the groundwater contribution to streamflow, especially in areas of water shortage or with high water demand. This study aims to improve the understanding of the interplay between quick- and baseflow components by revising a widely used baseflow separation method (WMO or IH-UK method). Baseflow Index (BFI) and quickflow-baseflow-regimes were analyzed for 50 meso-scale catchments in southwestern Germany and Switzerland along a pronounced altitudinal gradient from 200 to 3200 m asl. Since the graphical separation of the baseflow signal depends on the chosen method, we evaluated the separation procedure by analyzing the relation between the seasonal variability of the stable water isotope signal in streamflow and the contribution of the quickflow component. We found that the snowmelt signal in high-elevation catchments is mostly accounted as baseflow suggesting that the used method is only valid for catchment with pluvial regimes. The large variability of BFI values found between the low-elevation, rainfall-driven catchments indicates that here catchment controls such as hydrogeological characteristics determine the baseflow contribution to streamflow. Relationships between several physiographic characteristics and the BFI values differed systematically for rainfall- and snowmelt-driven catchments suggesting that besides quick- and baseflow another delayed storage contributes to streamflow in mountainous catchments. By adjusting the separation procedure (variation of filter parameters) we were able to separate more delayed contributions of snowmelt from the faster groundwater signal. Thus, variable filter parameters are helpful to identify delayed streamflow contributions from different sources (e.g. snow and groundwater). The study

  5. Contrasting climate change impact on river flows from high-altitude catchments in the Himalayan and Andes Mountains.

    Science.gov (United States)

    Ragettli, Silvan; Immerzeel, Walter W; Pellicciotti, Francesca

    2016-08-16

    Mountain ranges are the world's natural water towers and provide water resources for millions of people. However, their hydrological balance and possible future changes in river flow remain poorly understood because of high meteorological variability, physical inaccessibility, and the complex interplay between climate, cryosphere, and hydrological processes. Here, we use a state-of-the art glacio-hydrological model informed by data from high-altitude observations and the latest climate change scenarios to quantify the climate change impact on water resources of two contrasting catchments vulnerable to changes in the cryosphere. The two study catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites reveal a strong decrease in glacier area, they show a remarkably different hydrological response to projected climate change. In the Juncal catchment in Chile, runoff is likely to sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In the Langtang catchment in Nepal, future water availability is on the rise for decades to come with limited shifts between seasons. Owing to the high spatiotemporal resolution of the simulations and process complexity included in the modeling, the response times and the mechanisms underlying the variations in glacier area and river flow can be well constrained. The projections indicate that climate change adaptation in Central Chile should focus on dealing with a reduction in water availability, whereas in Nepal preparedness for flood extremes should be the policy priority.

  6. Impact of mountain permafrost on flow path and runoff response in a high alpine catchment

    Science.gov (United States)

    Rogger, M.; Chirico, G. B.; Hausmann, H.; Krainer, K.; Brückl, E.; Stadler, P.; Blöschl, G.

    2017-02-01

    Permafrost in high alpine catchments is expected to disappear in future warmer climates, but the hydrological impact of such changes is poorly understood. This paper investigates the flow paths and the hydrological response in a 5 km2 high alpine catchment in the Ötztal Alps, Austria, and their changes resulting from a loss of permafrost. Spatial permafrost distribution, depth to the permafrost table, and depth to the bedrock were mapped by geophysical methods. Catchment runoff and meteorological variables were monitored from June 2008 to December 2011. These data were used along with field experience to infer conceptual schemes of the dominant flow paths in four types of hillslopes that differ in terms of their unconsolidated sediment characteristics and the presence of permafrost. The four types are: talus fans, rock glaciers, Little Ice Age (LIA) till, and pre-LIA till. Permafrost tends to occur in the first three types, but is absent from pre-LIA till. Based on these flow path concepts, runoff was simulated for present conditions and for future conditions when permafrost has completely disappeared. The simulations indicate that complete disappearance of permafrost will reduce flood peaks by up to 17% and increase runoff during recession by up to 19%. It is argued that change modeling needs to account for flow path types and their changes based on geophysical surveys and field investigations.

  7. Bed load size distribution and flow conditions in a high mountain catchment of Central Pyrenees

    Directory of Open Access Journals (Sweden)

    Martínez-Castroviejo, Ricardo

    1990-06-01

    Full Text Available The bed load size distribution caused by different types of flow are compared in a high mountain catchment located in the upper Gallego river basin (Central Spanish’ Pyrenees. Three kinds of hydrologic events could be defined: those triggered by heavy autumn rainfalls, those originated by isolated summer rainstorms and those promoted by snowmelting. Each one is characterized by a peculiar bed load size distribution. Thus, it could be demonstrated that the coarser fractions, above 30 mm in diameter, are up to six times more abundant, in percentage of total weight, in transports caused by heavy rainfalls than in the material collected after snowmelt flows. In its turn, bed load mobilized by snowmelt flows is mainly composed by medium and fine gravel, from 2 to 8 mm. These may amount up to 60 % of total weight of bed load. The reasons for these so different size distributions are discussed.

    [es] En una cuenca de alta montaña localizada en el alto valle del río Gallego (Pirineo central se comparan las distribuciones por tamaños de los acarreos movilizados por diferentes tipos de caudal. Tres tipos de eventos hidrológicos han podido ser caracterizados: los ocasionados por intensas lluvias de otoño, los originados por tormentas estivales aisladas y los producidos por la fusión de la nieve acumulada durante el invierno. Se concluye que cada uno de ellos lleva asociada una distribución por tamaños típica de la carga de fondo. Así, se ha comprobado que las fracciones más gruesas consideradas -superiores a los 30 mm de diámetro- son hasta seis veces más abundantes -en porcentaje sobre el peso total- en las exportaciones causadas por lluvias de gran intensidad que en las generadas por caudales de fusión. A su vez, las descargas ocasionadas por la fusión arrastran principalmente gravas de calibre medio y fino -entre 2y8 mm- que llegan a suponer el 60 % en peso del volumen movilizado. Este artículo discute las razones que provocan

  8. Tracking channel bed resiliency in forested mountain catchments using high temporal resolution channel bed movement

    Science.gov (United States)

    Martin, Sarah E.; Conklin, Martha H.

    2018-01-01

    This study uses continuous-recording load cell pressure sensors in four, high-elevation (1500-1800 m), Sierra Nevada headwater streams to collect high-temporal-resolution, bedload-movement data for investigating the channel bed movement patterns within these streams for water years 2012-2014. Data show an annual pattern where channel bed material in the thalweg starts to build up in early fall, peaks around peak snow melt, and scours back to baseline levels during hydrograph drawdown and base flow. This pattern is punctuated by disturbance and recovery of channel bed material associated with short-term storm events. A conceptual model, linking sediment sources at the channel margins to patterns of channel bed fill and scour in the thalweg, is proposed building on the results of Martin et al. (2014). The material in the thalweg represents a balance between sediment supply from the channel margins and sporadic, conveyor-belt-like downstream transport in the thalweg. The conceptual model highlights not only the importance of production and transport rates but also that seasonal connectedness between the margins and thalweg is a key sediment control, determining the accumulation rate of sediment stores at the margins and the redistribution of sediment from margins to thalweg that feeds the conveyor belt. Disturbance and recovery cycles are observed at multiple temporal scales; but long term, the channel beds are stable, suggesting that the beds act as short-term storage for sediment but are in equilibrium interannually. The feasibility of use for these sensors in forested mountain stream environments is tested. Despite a high failure rate (50%), load cell pressure sensors show potential for high-temporal-resolution bedload measurements, allowing for the collection of channel bed movement data to move beyond time-integrated change measurements - where many of the subtleties of bedload movement patterns may be missed - to continuous and/or real-time measurements. This

  9. Assessment and management of debris-flow risk in a tropical high-mountain catchment in Santa Teresa, Peru

    Science.gov (United States)

    Frey, Holger; Buis, Daniel; Huggel, Christian; Bühler, Yves; Choquevilca, Walter; Fernandez, Felipe; García, Javier; Giráldez, Claudia; Loarte, Edwin; Masias, Paul; Portocarreo, César; Price, Karen; Walser, Marco

    2015-04-01

    movements and temporal damming of the river with trigger cables, geophones, and water level measurements. Independent energy supply, real-time data transfer to the data center in the municipality of Santa Teresa and remote access to the system via internet allows constant monitoring from within and outside the catchment. On a later stage the system is open to be enhanced by adding further sensors, cameras, meteorological stations, monitoring stations at glacier lakes, and related communication infrastructure. Risk management in such a context is a complex task: on one hand the data and information scarcity as well as the environmental conditions challenge scientific and technical aspects of debris-flow modeling and the design of the EWS. On the other hand, social aspects must be taken into account to make actions coherent with local risk perceptions and to achieve a good preparedness of the population. For a successful realization of the EWS and the entire risk management scheme, the local and regional institutional framework must also be considered. This contribution thus illustrates the implementation of an integrated risk management strategy under the challenging conditions common for remote high-mountain regions.

  10. Rainfall, runoff and sediment transport in a Mediterranean mountainous catchment.

    Science.gov (United States)

    Tuset, J; Vericat, D; Batalla, R J

    2016-01-01

    The relation between rainfall, runoff, erosion and sediment transport is highly variable in Mediterranean catchments. Their relation can be modified by land use changes and climate oscillations that, ultimately, will control water and sediment yields. This paper analyses rainfall, runoff and sediment transport relations in a meso-scale Mediterranean mountain catchment, the Ribera Salada (NE Iberian Peninsula). A total of 73 floods recorded between November 2005 and November 2008 at the Inglabaga Sediment Transport Station (114.5 km(2)) have been analysed. Suspended sediment transport and flow discharge were measured continuously. Rainfall data was obtained by means of direct rain gauges and daily rainfall reconstructions from radar information. Results indicate that the annual sediment yield (2.3 t km(-1) y(-1) on average) and the flood-based runoff coefficients (4.1% on average) are low. The Ribera Salada presents a low geomorphological and hydrological activity compared with other Mediterranean mountain catchments. Pearson correlations between rainfall, runoff and sediment transport variables were obtained. The hydrological response of the catchment is controlled by the base flows. The magnitude of suspended sediment concentrations is largely correlated with flood magnitude, while sediment load is correlated with the amount of direct runoff. Multivariate analysis shows that total suspended load can be predicted by integrating rainfall and runoff variables. The total direct runoff is the variable with more weight in the equation. Finally, three main hydro-sedimentary phases within the hydrological year are defined in this catchment: (a) Winter, where the catchment produces only water and very little sediment; (b) Spring, where the majority of water and sediment is produced; and (c) Summer-Autumn, when little runoff is produced but significant amount of sediments is exported out of the catchment. Results show as land use and climate change may have an important

  11. Contrasting climate change impact on river flows from high-altitude catchments in the Himalayan and Andes Mountains

    NARCIS (Netherlands)

    Ragettli, Silvan; Immerzeel, Walter W.; Pellicciotti, Francesca

    2016-01-01

    Mountain ranges are the world's natural water towers and provide water resources for millions of people. However, their hydrological balance and possible future changes in river flow remain poorly understood because of high meteorological variability, physical inaccessibility, and the complex

  12. Hydrological Regimes of Small Catchments in the High Tatra Mountains Before and After Extraordinary Wind-Induced Deforestation

    Science.gov (United States)

    Holko, Ladislav; Hlavata, Helena; Kostka, Zdenek; Novak, Jan

    2009-01-01

    The paper presents the results of rainfall-runoff data analysis for small catchments of the upper Poprad River affected by wind-induced deforestation in November 2004. Before-event and afterevent measured data were compared in order to assess the impact of deforestation on hydrological regimes. Several characteristics were used including water balance, minimum and maximum runoff, runoff thresholds, number of runoff events, selected characteristics of events, runoff coefficients, and flashiness indices. Despite increased spring runoff minima, which in one catchment (Velick Creek) exceeded previously observed values after deforestation took place, it can be generally concluded that the impact of the deforestation was not clearly manifested in the analyzed hydrological data.

  13. HIGH-RESOLUTION SPATIAL MODELING OF DAILY WEATHER ELEMENTS FOR A CATCHMENT IN THE OREGON CASCADE MOUNTAINS, UNITED STATES

    Science.gov (United States)

    High-quality, daily meteorological data at high spatial resolution are essential for a variety of hydrologic and ecological modeling applications that support environmental risk assessments and decision making. This paper describes the development, application, and assessment of ...

  14. The nitrate export in subtropical mountainous catchment: implication for land use change impact

    Science.gov (United States)

    Huang, J.-C.; Lee, T.-Y.; Kao, S.-J.; Hsu, S.-C.; Lin, H.-J.; Peng, T.-R.

    2010-12-01

    Agricultural activity is the dominant factor affecting water quality and nitrate export, which causes eutrophication and episodic acidification in downstream water bodies (e.g., reservoirs, lakes, and coastal zones). However, in subtropical mountainous areas such environmental impact due to the land use change was rarely documented. In this study, we investigated 16 sub-catchments during 2007 and 2008 in the Chi-Chia-Wan catchment where is the sole habitat for the endemic species, Formosan landlocked salmon (Oncorhynchus masou formosanus). The results revealed that the NO3-N concentration in pristine catchments varied from 0.144 to 0.151 mg/L without significant seasonal variation. This concentration was comparable with other forestry catchments around the world. However, the annual nitrate export was around 375.3-677.1 kg/km2/yr, much higher than other catchments due to the greater amount of rainfall. This is an important baseline for comparisons with other climate areas. As for the impact of agricultural activities, the catchments with some human disturbance, ~5.2% of the catchment area, might yield 5947.2 kg N/km2/yr - over 10-times higher than that of pristine catchment. Such high export caused by such a low level of disturbance might indicate that subtropical mountainous area is highly sensitive to agricultural activities. As for the land-use effect on nitrate yield, the forestry land might yield 488.5 ± 325.1 kg/km2/yr and the vegetable farm could yield 298 465.4 ± 3347.2 kg/km2/yr - 1000-times greater than the forestry. The estimated nitrate yields for land use classes were a crucial basis and useful for the land manager to assess the possible impacts (e.g., non-point source pollution evaluation and the recovery of land expropriation).

  15. Hydrological effects of fire in South-African mountain catchments

    CSIR Research Space (South Africa)

    Scott, DF

    1993-10-01

    Full Text Available stream_source_info scott_1993.pdf.txt stream_content_type text/plain stream_size 66977 Content-Encoding ISO-8859-1 stream_name scott_1993.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Journal of Hydrology, 150... (1993) 409 432 0022-1694/93/$06.00 ~: 1993 Elsevier Science Publishers B.V. All rights reserved 409 \\[3\\] The hydrological effects of fire in South African mountain catchments D.F. Scott CSIR Division of Forest Science...

  16. Inferring runoff generation processes through high resolution spatial and temporal UV-Vis absorbance measurements in a mountainous headwater catchment in Southern Ecuador

    Science.gov (United States)

    Windhorst, David; Schob, Sarah; Zang, Carina; Crespo, Patricio; Breuer, Lutz

    2015-04-01

    The alpine grassland páramo - typically occurring in the headwater catchments of the Andes - plays an important role in flow regulation, hydropower generation and local water supply. However, hydrological and hydro-biogeochemical processes in the páramo and their potential reactions to climate and land use change are largely unknown. Therefore, we used a UV-Vis absorbance spectrometer to investigate fluxes of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity and nitrate (NO3-N) in a small headwater catchment (91.31 km²) in the páramo in south Ecuador on a 5 min temporal and 100 m spatial resolution to gain first insights in its hydrological functioning. Spatial sampling was realized during three snapshot sampling campaigns along the 14.2 km long stream between October 2013 and January 2014, while temporal sampling took place at a permanent sampling site within the catchment between February and June 2014. To identify the runoff generation processes the spatial patterns have been associated with local site specific (e.g. fish ponds) and sub-catchment wide (e.g. land use) characteristics. Storm flow events within the time series allowed to further study temporal changes and rotational patterns of concentration-discharge relations (hysteresis). In total, 35 events were identified to be suitable for analyzing hysteresis effects of BOD, COD, and turbidity. Nitrate concentrations could be studied for 20 events. Regardless of the flow conditions nitrate leaching increased with a growing share of non-native pine forests or pastures in the study area. During low flow conditions, the high water holding capacity of the upstream páramo areas ensured a continuous supply of BOD to the stream. Pasture and pine forest sites, mostly occurring in the downstream section of the stream, contributed to BOD only during discharge events. Contradicting the expectations the trout farms along the lower part of the streams had a relatively closed nutrient cycle and

  17. Flood-type classification in mountainous catchments using crisp and fuzzy decision trees

    Science.gov (United States)

    Sikorska, Anna E.; Viviroli, Daniel; Seibert, Jan

    2015-10-01

    Floods are governed by largely varying processes and thus exhibit various behaviors. Classification of flood events into flood types and the determination of their respective frequency is therefore important for a better understanding and prediction of floods. This study presents a flood classification for identifying flood patterns at a catchment scale by means of a fuzzy decision tree. Hence, events are represented as a spectrum of six main possible flood types that are attributed with their degree of acceptance. Considered types are flash, short rainfall, long rainfall, snow-melt, rainfall on snow and, in high alpine catchments, glacier-melt floods. The fuzzy decision tree also makes it possible to acknowledge the uncertainty present in the identification of flood processes and thus allows for more reliable flood class estimates than using a crisp decision tree, which identifies one flood type per event. Based on the data set in nine Swiss mountainous catchments, it was demonstrated that this approach is less sensitive to uncertainties in the classification attributes than the classical crisp approach. These results show that the fuzzy approach bears additional potential for analyses of flood patterns at a catchment scale and thereby it provides more realistic representation of flood processes.

  18. Ensemble Modeling of Suspended Sediment in Steep Mountain Catchments

    Science.gov (United States)

    Stewart, J.; Raseman, W. J.; Kasprzyk, J. R.; Livneh, B.

    2016-12-01

    Climatic and land cover changes present important uncertainties into the rates of soil erosion and sedimentation in watersheds. Soil erosion adds constituents to streams, altering water chemistry and streambed morphology, which can adversely affect aquatic life and poses a critical challenge for water treatment and reservoir management. The goal of this research is to establish estimates of sediment transport within large-scale mountainous catchments (>1000 km2). As sedimentation rates are impacted by numerous physical processes including soil, land cover, slope and climate; the results from seven models will be presented to quantify uncertainty and improve predictability. A broader inquiry made here is into the efficacy of model structure under different conditions. We present the results from empirical, stochastic, conceptual and physical models. These include empirical models: monovariate rating curve, multivariate regression and the Modified Universal Soil Loss Equation (MUSLE), to models with conceptual components: Soil Water Assessment Tool (SWAT) to more physically based models: Water Erosion Prediction Project (WEPP), Precipitation Runoff Modeling System (PRMS) and Distributed Hydrology Soil Vegetation Model (DHSVM). Key uncertainties will be characterized resulting from forcing inputs, parameter selection, scale discretization, and model structure. Calibration results from a multi-objective optimization routine will be presented that optimize parameters and identify performance trade-offs that will be used to develop uncertainty estimates in both streamflow and sediment projections. The outcomes of this research will highlight critical issues relevant to large-scale hydrologic and suspended sediment prediction initiatives.

  19. Flood events in small mountain catchments : observations and results from the Draix experimental basins (French South Alps)

    Science.gov (United States)

    Mathys, N.; Klotz, S.

    2009-04-01

    The floods generated in small mountains basin are flash floods often devastating. Predicting runoff, erosion and sediment yield within mountainous catchments presents a strategic interest due to the consequences which arise from these phenomenons and the need for natural hazard mitigation engineering. The need to quantify the phenomenon and the effect of the restoration strategies led the Cemagref to monitor a group of little basins in the Southern French Alps : the Draix field Observatory on hydrological and erosional processes in mountain areas. The main goal of this laboratory is to improve the prediction of the runoff and erosion response of small mountain catchments to climatological inputs (precipitation and temperature), particularly for extreme events. A focus is given on the spatial and temporal variability of rainfall at the scale of a small mountainous catchment, on the hydrological response of these small catchments to this input, on the role of the vegetation cover in these processes. The experimental basins of Draix are located 200 km South of Grenoble, near the little town of Digne. Five basins have been equipped since 1982 for the measurement of rainfall, liquid discharge and solid transport, which can be both bedload and suspension. These basins have different areas, from 1300 m² to 1 km². Four are located in denuded areas with vegetation cover ranging from 21 % to 56 %; the last one was reforested at the end of the last century, within the frame of restoration works. 87 % of its surface area is now covered with a pine forest. The paper will present a summary on the conditions of occurrence of the high floods for the different basin scale. As two catchments of nearly 1 km², have homogeneous but different vegetation covers, a comparison can be made and highlights the effect of the vegetation cover on the flood generation.

  20. Rocky Mountain High.

    Science.gov (United States)

    Hill, David

    2001-01-01

    Describes Colorado's Eagle Rock School, which offers troubled teens a fresh start by transporting them to a tuition- free campus high in the mountains. The program encourages spiritual development as well as academic growth. The atmosphere is warm, loving, structured, and nonthreatening. The article profiles several students' experiences at the…

  1. Water storage and mixing in a Californian mountain catchment during a multiyear drought.

    Science.gov (United States)

    van der Velde, Ype; Visser, Ate; Thaw, Melissa; Safeeq, Mohammad

    2017-04-01

    From 2012 to 2016, a five year period of intensive drought hit the Californian Sierra Nevada. We use this drought period as an opportunity to investigate how catchment water storage and mixing differs between prolonged wet and dry conditions using long term datasets of river discharge, evapotranspiration, water quality, and isotopes. Characteristic features of our test catchment include a thick (>5m) unsaturated zone in deeply weathered granite mountain soils, snow melt and events of high intensity rainfall, dry summers and numerous wetland meadows along the stream. Our data and model analysis suggest that under the driest conditions, river flow predominantly consist of deep groundwater tapped by deeply incised sections of the stream, while the wetlands store their water just below the root system of its shallow rooting vegetation. In contrast, during wet periods, most runoff is generated on the flat wetland meadows, while the regional groundwater system slowly refills itself as water trickles through the thick unsaturated zone, creating a delayed response. These contrasting response timescales of the catchment-wide groundwater system and the local wetland systems seem to weaken as the drought progresses and connectivity between groundwater flow and wetlands decreases. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-717438

  2. Quantitative reconstruction of past soil erosion in the Kirschgraben catchment (Spessart mountains, Central Europe)

    Science.gov (United States)

    Kranz, Annegret; Bork, Hans-Rudolf; Nelle, Oliver; Müller, Ulrich; Fuchs, Markus; Fuelling, Alexander

    2010-05-01

    An important problem in Holocene landscape reconstruction is quantifying the relative roles of climatic change and human impact. This project aims to quantify and mass-balance sediment flux in high temporal and spatial resolution, therefore a relatively small gully catchment (Kirschgraben) in the low mountain range Spessart (Germany, Lower Franconia) was chosen as a research area. The catchment is 42 ha in size and total relief is ~200 m. Bedrock is composed of Bunter Sandstone, large areas of which are loess mantled. In the intersection between Kirschgraben fan and the alluvial plain of the Elsava River a moated archaeological site was recently excavated. On the basis of process-based stratigraphy and preliminary chronology, a detailed sequence of landscape changes can be interpreted. Gully incision into Pleistocene sand and gravel sediments during early Holocene resulted in rapid fan development. Non-deposition on the fan surface and minor infilling of the gully system suggests relative catchment stability persisted during prehistoric times, at least until the early iron ages, when human occupation of the fan surface is first recorded. The first evidence of human impact, although minor, is represented by thin colluvial layers on the lower slopes during late Neolithic period. Subsequently, almost the entire catchment has been under agricultural use from the early medieval periods on, and well preserved within field terraces along ancient tenure borders. These features demonstrate widespread and intensive soil loss from the slopes, and eroded material is also preserved in various sediment traps within the catchment. Charcoal production in the catchment probably began at the same time as the widespread soil loss, and lasted until ca. 1900 AD. Anthracological investigations provide the opportunity to reconstruct the vegetation composition on a local scale, and is combined with paleobotanical macro remains and pollen analysis. Initial results indicate a rotating wood

  3. Nitrate in Polluted Mountainous Catchments with Mediterranean Climates

    Directory of Open Access Journals (Sweden)

    Thomas Meixner

    2001-01-01

    Full Text Available The mountains of southern California receive some of the highest rates of nitrogen (N deposition in the world (~40 kg ha�1 year�1. These high rates of deposition have translated into consistently high levels of nitrate (NO3� in some streams of the San Bernardino Mountains. However, not all streams are exhibiting these high levels of NO3�. Perennial streams have high NO3� concentrations (~200 [b.mu ]moles l�1 while ephemeral streams do not (~20 [b.mu ]moles l�1. This difference points to groundwater as the source of the NO3� observed in streams. Furthermore, the evidence indicates a differential impact of N deposition on terrestrial and aquatic systems in Mediterranean climates, with aquatic systems being impacted more quickly. The primary reason for this difference involves the asynchrony between the time that atmospheric deposition occurs (summer, the time period of maximum soil NO3� availability and leaching (winter, and the time of maximum plant N demand (spring. Our results indicate that semiarid Mediterranean climate systems behave differently from more humid systems in that, because of this asynchrony, aquatic systems may not be indicative of changes in terrestrial ecosystem response. These differences lead us to the conclusion that the extrapolation of impacts from humid to Mediterranean climates is problematic and the concept of N saturation may need to be revisited for semiarid and seasonally dry systems.

  4. Internal evaluation of a physically-based distributed model using data from a Mediterranean mountain catchment

    OpenAIRE

    Anderton, S. P.; J. Latron; White, S M; P. Llorens; Gallart, F.; C. Salvany; P. E. O’Connell

    2002-01-01

    International audience; An evaluation of the performance of a physically-based distributed model of a small Mediterranean mountain catchment is presented. This was carried out using hydrological response data, including measurements of runoff, soil moisture, phreatic surface level and actual evapotranspiration. A-priori model parameterisation was based as far as possible on property data measured in the catchment. Limited model calibration was required to identify an appropriate value for ter...

  5. Hydrological processes and their seasonal controls in a small Mediterranean mountain catchment in the Pyrenees

    Science.gov (United States)

    Gallart, F.; Llorens, P.; Latron, J.; Regüés, D.

    The Vallcebre catchments are located in a middle mountain area of the Pyrenean ranges, built up by sedimentary rocks and loamy soils. The vegetation cover is pastures and forests of Pinus sylvestris, mostly occupying former agricultural terraces. Some relatively small, heavily eroded landscapes (badlands) occur in the catchments, playing a relevant hydrological and geomorphic role. Annual precipitation is 924 mm and potential (reference) evapotranspiration is about 700 mm. Rainfall interception in forests represents about 24% of precipitation; interception rates were similar throughout the seasons because of a compensation between rainfall intensities and atmospheric conditions. Soil moisture showed a temporal pattern characterised by the occurrence of marked deficit periods in summer and also, but less pronounced, in winter. During most of the year, subsurface flows on hillslopes drove the spatial organisation of soil moisture and the occurrence of saturated areas. Nevertheless, this spatial organisation was also controlled by the patterns of vegetation cover. During dry periods, subsurface flow ceased, saturated areas disappeared and the spatial patterns of soil moisture changed. Stream flow from these catchments was dominated by storm flow, and the runoff generating mechanisms showed a clear seasonal pattern, controlled mainly by the soil moisture and the extent of saturated areas. During the dry periods, runoff was produced only on impervious areas and badlands. At the end of the dry periods, some large rainfall events generated significant runoff because of the perched saturation of the shallow soil horizons. Thereafter, runoff generation was dominated by the role of saturated areas. Stream waters in catchments with badlands had very high suspended sediment concentrations. The seasonal pattern of erosion processes in badlands was characterised by physical weathering during winter, regolith breakdown and vigorous hillslope erosion during spring and summer, and

  6. Hydrological processes and their seasonal controls in a small Mediterranean mountain catchment in the Pyrenees

    Directory of Open Access Journals (Sweden)

    F. Gallart

    2002-01-01

    Full Text Available The Vallcebre catchments are located in a middle mountain area of the Pyrenean ranges, built up by sedimentary rocks and loamy soils. The vegetation cover is pastures and forests of Pinus sylvestris, mostly occupying former agricultural terraces. Some relatively small, heavily eroded landscapes (badlands occur in the catchments, playing a relevant hydrological and geomorphic role. Annual precipitation is 924 mm and potential (reference evapotranspiration is about 700 mm. Rainfall interception in forests represents about 24% of precipitation; interception rates were similar throughout the seasons because of a compensation between rainfall intensities and atmospheric conditions. Soil moisture showed a temporal pattern characterised by the occurrence of marked deficit periods in summer and also, but less pronounced, in winter. During most of the year, subsurface flows on hillslopes drove the spatial organisation of soil moisture and the occurrence of saturated areas. Nevertheless, this spatial organisation was also controlled by the patterns of vegetation cover. During dry periods, subsurface flow ceased, saturated areas disappeared and the spatial patterns of soil moisture changed. Stream flow from these catchments was dominated by storm flow, and the runoff generating mechanisms showed a clear seasonal pattern, controlled mainly by the soil moisture and the extent of saturated areas. During the dry periods, runoff was produced only on impervious areas and badlands. At the end of the dry periods, some large rainfall events generated significant runoff because of the perched saturation of the shallow soil horizons. Thereafter, runoff generation was dominated by the role of saturated areas. Stream waters in catchments with badlands had very high suspended sediment concentrations. The seasonal pattern of erosion processes in badlands was characterised by physical weathering during winter, regolith breakdown and vigorous hillslope erosion during

  7. Contrasting Climate Change Impact on River Flow from Glacierised Catchments in the Himalayan and Andes Mountains

    Science.gov (United States)

    Pellicciotti, F.; Ragettli, S.; Immerzeel, W. W. W.

    2016-12-01

    Glaciers and glacierised catchments in mountainous regions react to a changing climate in different manners depending on climate and glacier characteristics. Despite the key role of mountain ranges as natural water towers, their hydrological balance and future changes in glacier runoff associated with climate warming remain poorly understood because of high meteorological variability, physical inaccessibility and the complex interplay between climate, cryosphere and hydrological processes. We use a state-of-the art glacio-hydrological model informed by data from high altitude observations and the latest CMIP5 climate change scenarios to quantify the climate change impact on glaciers and runoff for two contrasting catchments vulnerable to changes in the cryosphere. The two catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites are projected to experience a strong decrease in glacier area, they show remarkably different hydrological responses. Icemelt is on a rising limb in Langtang at least until 2041-2050 and starts to decrease afterwards, while in Juncal icemelt was already beyond its tipping point at the beginning of the 21st century. This contrasting response can be explained by differences in the elevation distribution of the glaciers in the two regions. In Juncal, many glaciers are melting up to the highest elevations already during the reference period (2000-2010) and increasing melt rates due to higher air temperatures cannot compensate the loss of glacier area. In Langtang, large sections of the glaciers at high elevations are currently not exposed to melt, but will be in the future, thus compensating for the loss of glacier area at lower elevations. As a result of these changes and projected changes in precipitation, in Juncal runoff will sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In Langtang, future water

  8. Toward Characterizing the 4D Structure of Precipitation at the Headwater Catchment Scale in Mountainous Regions

    Science.gov (United States)

    Barros, A. P.; Prat, O. P.; Sun, X.; Shrestha, P.; Miller, D.

    2009-04-01

    generalized. It requires understanding the physical controls that govern the diurnal cycle and how these physical controls translate into spatial and temporal variability of dynamics and microphysics of precipitation in headwater catchments, and especially in the context of extreme events for natural hazards assessments. Toward this goal, we have initiated a sequence of number of intense observing period (IOP) campaigns in the Great Smoky Mountains National Park using radiosondes, tethersondes, microrain radars, and a high resolution raingauge network that for the first time monitors rainfall systematically along ridges in the Appalachians. Along with field observations, a high-resolution coupled model has been implemented to diagnose the evolution of the 4D structure of regional circulations and associated precipitation for IOP conditions and for reconstructing historical extremes associated with the interaction of tropical cyclones with the mountains. A synthesis of data analysis and model simulations will be presented.

  9. Rainfall-Runoff Dynamics Following Wildfire in Mountainous Headwater Catchments, Alberta, Canada.

    Science.gov (United States)

    Williams, C.; Silins, U.; Bladon, K. D.; Martens, A. M.; Wagner, M. J.; Anderson, A.

    2015-12-01

    Severe wildfire has been shown to increase the magnitude and advance the timing of rainfall-generated stormflows across a range of hydro-climate regions. Loss of canopy and forest floor interception results in increased net precipitation which, along with the removal of forest organic layers and increased shorter-term water repellency, can result in strongly increased surface flow pathways and efficient routing of precipitation to streams. These abrupt changes have the potential to exacerbate flood impacts and alter the timing of runoff delivery to streams. However, while these effects are well documented in drier temperate mountain regions, changes in post-fire rainfall-runoff processes are less well understood in colder, more northern, snowfall dominated regimes. The objectives of this study are to explore longer term precipitation and runoff dynamics of burned and unburned (reference) watersheds from the Southern Rockies Watershed Project (SRWP) after the 2003 Lost Creek wildfire in the front-range Rocky Mountains of southwestern Alberta, Canada. Streamflow and precipitation were measured in 5 watersheds (3.7 - 10.4 km2) for 10 years following the wildfire (2005-2014). Measurements were collected from a dense network of meteorological and hydrometric stations. Stormflow volume, peak flow, time to peak flow, and total annual streamflow were compared between burned and reference streams. Event-based data were separated into 3 post-fire periods to detect changes in rainfall-runoff dynamics as vegetation regenerated. Despite large increases in post-fire snowpacks and net summer rainfall, rainfall-generated runoff from fire-affected watersheds was not large in comparison to that reported from more temperate snowfall-dominated Rocky Mountain hydrologic settings. High proportions of groundwater contribution to annual runoff regimes (as opposed to surface flow pathways) and groundwater storage were likely contributors to greater watershed resistance to wildfire effects

  10. Hydrological response of afforestation in a Mediterranean mountain area: the Araguás Afforestation catchment

    Science.gov (United States)

    Nadal Romero, Estela; Cammeraat, Erik; Serrano Muela, Pili; Lana-Renault, Noemi; Regüés, David

    2015-04-01

    The fraction of forest cover in the Mediterranean region is increasing due to afforestation programs conducted by national forest services and also due to natural revegetation processes. Literature review suggests that afforestation might threaten water resources because it (i) reduces the number of floods and many rainfall events produce no notable flow; (ii) decreases annual water yield and low flows; (iii) delays peak flows but increases the duration of floods; and (iv) increases rainfall interception, reducing the water reaching the soil. Also, afforestation typically reduces erosion risk and the volume of sediment reaching the streams, but not during the first years after plantation due to high geomorphic activity when invasive techniques are used. Although the great amount of literature on these topics, there is still considerable scientific uncertainty about the impact of afforestation on extreme events and groundwater dynamics. The MED-AFFOREST project studies the effects of afforestation on the hydrological response of a small catchment (Araguás afforestation catchment) monitored in the Central Spanish Pyrenees. In this study, we present the first results , as an example of the likely effects of afforestation in Mediterranean mountain areas. The results show that the hydrological response in the afforestation area is variable and complex, because the discharge was generated by a combination of different runoff generation processes. Acknowledgments This research was supported by a Marie Curie Intra-European Fellowship in the project "MED-AFFOREST" (PIEF-GA-2013-624974).

  11. Controls on hillslope stability in a mountain river catchment

    Science.gov (United States)

    Golly, Antonius; Turowski, Jens; Hovius, Niels; Badoux, Alexandre

    2015-04-01

    Sediment transport in fluvial systems accounts for a large fraction of natural hazard damage costs in mountainous regions and is an important factor for risk mitigation, engineering and ecology. Although sediment transport in high-gradient channels gathered research interest over the last decades, sediment dynamics in steep streams are generally not well understood. For instance, the sourcing of the sediment and when and how it is actually mobilized is largely undescribed. In the Erlenbach, a mountain torrent in the Swiss Prealps, we study the mechanistic relations between in-channel hydrology, channel morphology, external climatic controls and the surrounding sediment sources to identify relevant process domains for sediment input and their characteristic scales. Here, we analyze the motion of a slow-moving landslide complex that was permanently monitored by time-lapse cameras over a period of 70 days at a 30 minutes interval. In addition, data sets for stream discharge, air temperature and precipitation rates are available. Apparent changes in the channel morphology, e.g. the destruction of channel-spanning bed forms, were manually determined from the time-lapse images and were treated as event marks in the time series. We identify five relevant types of sediment displacement processes emerging during the hillslope motion: concentrated mud flows, deep seated hillslope failure, catastrophic cavity failure, hillslope bank erosion and individual grain loss. Generally, sediment displacement occurs on a large range of temporal and spatial scales and sediment dynamics in steep streams not only depend on large floods with long recurrence intervals. We find that each type of displacement acts in a specific temporal and spatial domain with their characteristic scales. Different external climatic forcing (e.g. high-intensity vs. long-lasting precipitation events) promote different displacement processes. Stream morphology and the presence of boulders have a large effect on

  12. Suspended sediment apportionment in a South-Korean mountain catchment

    Science.gov (United States)

    Birkholz, Axel; Meusburger, Katrin; Park, Ji-Hyung; Alewell, Christine

    2016-04-01

    Due to the rapid agricultural expansion and intensification during the last decades in South-Korea, large areas of hill slope forests were transformed to paddies and vegetable fields. The intensive agriculture and the easily erodible soils in our catchment are a major reason for the increased erosion causing suspended sediments to infiltrate into the close drinking water reservoir. The drinking water reservoir Lake Soyang provides water supply for over ten million people in Seoul. Landscape managers need to know the exact origin of these sediments before they can create landscape amelioration schemes. We applied a compound-specific stable isotope (CSSI) approach (Alewell et al., 2015) to apportion the sources of the suspended sediments between forest and agricultural soil contribution to the suspended sediments in a different catchment and applied the same approach to identify and quantify the different sources of the suspended sediments in the river(s) contributing to Lake Soyang. We sampled eight soil sites within the catchment considering the different landuse types forest, rice paddies, maize and vegetables. Suspended sediments were sampled at three outlets of the different sub-catchments. Soils and suspended sediments are analysed for bulk carbon and nitrogen isotopes, compound-specific carbon isotopes of plant-wax derived long-chain fatty acids and long-chain n-alkanes. Fatty acid and alkane isotopes are then used in mixing calculations and the mixing model software IsoSource to find out the contribution of the different source soils to the suspended sediments. We present first data of the source soils and the suspended sediments. C. Alewell, A. Birkholz, K. Meusburger, Y. Schindler-Wildhaber, L. Mabit, 2015. Sediment source attribution from multiple land use systems with CSIA. Biogeosciences Discuss. 12: 14245-14269.

  13. Groundwater vulnerability assessment in Jaworzynka's Valley catchment basin (Tatra Mountains, Poland)

    Science.gov (United States)

    Cypel, M.

    2012-04-01

    During the research an attempt was made to assess an intrinsic groundwater vulnerability to contamination in Tatra Mountains (Poland. Assessment of the degree of hazard of permeating pollutions from land surface directly to the ground water table was the main target of the research. The Jaworzynka's Valley in West Tatra Mountains was chosen as the exact research area. Jaworzynka's Valley is a typical karst catchment basin. Location of study area wasn't accidental, because in the north part of the valley there is a well which is being used as drinking water intake for the whole Zakopane City. This is the reason, why the quality of ground water is so important. The method used in this research, entitled KARSTIC, wasn't applied in Poland before. This is a parametric method of groundwater vulnerability assessment. KARSTIC is a modification of much better known DRASTIC method, specialized for specific karst terrain. KARSTIC method created by A. Davis and others (1994), was used for the first time, during a research in the Black Hills Mountains, USA. Research in Jaworzynka's Valley was based on the Black Hills study. In order to apply this method in Tatra Mountains, it was necessary to make a few changes in relation to original area. Applying KARSTIC method consists of successive stages. Schematization of hydrogeological conditions is an inseparable part of KARSTIC method. The first step bases on collecting all of available data such as maps, databases and documentations. Next stage consists of classifying all parameters employed in this method and then assigning a ratings and weights for this parameters. Subsequently it is necessary to use a mathematical formula, named Pollution Potential Index, which presents a ground water vulnerability in each point. The final step is visualization on the ground water vulnerability map. The result of research displays the high vulnerability in close proximity of the drinking water intake. The most vulnerable areas in Jaworzynka

  14. A comparative high-altitude meteorological analysis from three catchments in the Nepalese Himalaya

    NARCIS (Netherlands)

    Shea, J. M.; Wagnon, P.; Immerzeel, W. W.|info:eu-repo/dai/nl/290472113; Biron, R.; Brun, F.; Pellicciotti, F.

    2015-01-01

    Meteorological studies in high-mountain environments form the basis of our understanding of catchment hydrology and glacier accumulation and melt processes, yet high-altitude (>4000 m above sea level, asl) observatories are rare. This research presents meteorological data recorded between December

  15. Spatial rainfall variability and runoff response during an extreme event in a semi-arid catchment in the South Pare Mountains, Tanzania

    NARCIS (Netherlands)

    Mul, M.L.; Savenije, H.H.G.; Uhlenbrook, S.

    2009-01-01

    OA fund TU Delft This paper describes an extreme flood event that occurred in the South Pare Mountains in northern Tanzania. A high spatial and temporal resolution data set has been gathered in a previously ungauged catchment. This data was analysed using a multi-method approach, to gather

  16. Depth and Areal Distribution of Cs-137 in the Soil of a Small Water Catchment in the Sopron Mountains

    National Research Council Canada - National Science Library

    Ervin Kiss; Péter Volford

    2013-01-01

    The study presents the depth and areal distribution of Cs-137 activity concentration in the forest soils of Farkas Trench, a small water catchment in the Sopron Mountains, in 2001 and 2010, moreover...

  17. The Role of Catchment Soil and Geologic Properties in Governing Mountain Streamflow Response to Climate Change

    Science.gov (United States)

    Nguyen, T. T.; Tague, C.; Adam, J. C.

    2016-12-01

    Mountainous catchments are important sources of water supply for downstream areas, but this water is particularly vulnerable to projected climate change as many of these catchments are snowmelt dominant. Recent regional studies projected climate change to cause decline in snowpack and earlier snowmelt resulting in low summer flow in streams. However, average large scale hydrologic changes to future climate might not be the same at smaller catchment scales, when considering the differences in physical characteristics, such as soil and geology. The aim of this study is to explore how soil and geology-related parameters affect different metrics of climate elasticity of streamflow (i.e. 7-day minimum, seasonal and annual average) across three catchments in the Yakima River Basin in central Washington using a physically based hydro-ecological model, the Regional Hydro-Ecologic Simulation System (RHESSys). Optimal constrained model parameters for each catchment were first determined using a global optimization tool, Hybrid Covariance Matrix Adaptation Evolution Strategy (HCMA) based on published soil, geologic and streamflow data. Using the mean and covariance matrix of parameters obtained from HCMA, a number of parameter sets were randomly generated and subsequently used within the Distributed Evaluation of Local Sensitivity Analysis (DELSA) framework to explore their importance in governing streamflow response to climate perturbation. Our results show that soil and geologic parameters have distinct levels of sensitivities in each catchment. Moreover, the sensitivities of these parameters vary not only with changing temperature and precipitation but also with different metrics of climate elasticity of streamflow. Importantly, results reveal that dominant parameters also change over time thus choosing the most relevant parameter set for a particular catchment is of great importance for climate change studies. This research could be useful for predicting the responses of

  18. Surface fluxes and water balance of spatially varying vegetation within a small mountainous headwater catchment

    Directory of Open Access Journals (Sweden)

    G. N. Flerchinger

    2010-06-01

    Full Text Available Precipitation variability and complex topography often create a mosaic of vegetation communities in mountainous headwater catchments, creating a challenge for measuring and interpreting energy and mass fluxes. Understanding the role of these communities in modulating energy, water and carbon fluxes is critical to quantifying the variability in energy, carbon, and water balances across landscapes. The focus of this paper was: (1 to demonstrate the utility of eddy covariance (EC systems in estimating the evapotranspiration component of the water balance of complex headwater mountain catchments; and (2 to compare and contrast the seasonal surface energy and carbon fluxes across a headwater catchment characterized by large variability in precipitation and vegetation cover. Eddy covariance systems were used to measure surface fluxes over sagebrush (Artemesia arbuscula and Artemesia tridentada vaseyana, aspen (Populus tremuloides and the understory of grasses and forbs beneath the aspen canopy. Peak leaf area index of the sagebrush, aspen, and aspen understory was 0.77, 1.35, and 1.20, respectively. The sagebrush and aspen canopies were subject to similar meteorological forces, while the understory of the aspen was sheltered from the wind. Missing periods of measured data were common and made it necessary to extrapolate measured fluxes to the missing periods using a combination of measured and simulated data. Estimated cumulative evapotranspiratation from the sagebrush, aspen trees, and aspen understory were 384 mm, 314 mm and 185 mm. A water balance of the catchment indicated that of the 699 mm of areal average precipitation, 421 mm was lost to evapotranspiration, and 254 mm of streamflow was measured from the catchment; water balance closure for the catchment was within 22 mm. Fluxes of latent heat and carbon for all sites were minimal through the winter. Growing season fluxes of latent heat and carbon were consistently higher

  19. Internal evaluation of a physically-based distributed model using data from a Mediterranean mountain catchment

    Directory of Open Access Journals (Sweden)

    S. P. Anderton

    2002-01-01

    Full Text Available An evaluation of the performance of a physically-based distributed model of a small Mediterranean mountain catchment is presented. This was carried out using hydrological response data, including measurements of runoff, soil moisture, phreatic surface level and actual evapotranspiration. A-priori model parameterisation was based as far as possible on property data measured in the catchment. Limited model calibration was required to identify an appropriate value for terms controlling water loss to a deeper regional aquifer. The model provided good results for an initial calibration period, when judged in terms of catchment discharge. However, model performance for runoff declined substantially when evaluated against a consecutive, rather drier, period of data. Evaluation against other catchment responses allowed identification of the problems responsible for the observed lack of model robustness in flow simulation. In particular, it was shown that an incorrect parameterisation of the soil water model was preventing adequate representation of drainage from soils during hydrograph recessions. This excess moisture was then being removed via an overestimation of evapotranspiration. It also appeared that the model underestimated canopy interception. The results presented here suggest that model evaluation against catchment scale variables summarising its water balance can be of great use in identifying problems with model parameterisation, even for distributed models. Evaluation using spatially distributed data yielded less useful information on model performance, owing to the relative sparseness of data points, and problems of mismatch of scale between the measurement and the model grid. Keywords: physically-based distributed model, SHETRAN, parameterisation, Mediterranean mountain catchment, internal evaluation, multi-response

  20. Spatial and temporal variability of snow depth and ablation rates in a small mountain catchment

    Directory of Open Access Journals (Sweden)

    T. Grünewald

    2010-05-01

    Full Text Available The spatio-temporal variability of the mountain snow cover determines the avalanche danger, snow water storage, permafrost distribution and the local distribution of fauna and flora. Using a new type of terrestrial laser scanner, which is particularly suited for measurements of snow covered surfaces, snow depth was monitored in a high alpine catchment during an ablation period. From these measurements snow water equivalents and ablation rates were calculated. This allowed us for the first time to obtain a high resolution (2.5 m cell size picture of spatial variability of the snow cover and its temporal development. A very high variability of the snow cover with snow depths between 0–9 m at the end of the accumulation season was observed. This variability decreased during the ablation phase, while the dominant snow deposition features remained intact. The average daily ablation rate was between 15 mm/d snow water equivalent at the beginning of the ablation period and 30 mm/d at the end. The spatial variation of ablation rates increased during the ablation season and could not be explained in a simple manner by geographical or meteorological parameters, which suggests significant lateral energy fluxes contributing to observed melt. It is qualitatively shown that the effect of the lateral energy transport must increase as the fraction of snow free surfaces increases during the ablation period.

  1. Tracing fine sediment sources in small mountain catchment.

    Science.gov (United States)

    Kouhpeima, A; Feiznia, S; Ahmadi, H

    2011-01-01

    Fine sediment represents an important diffuse source pollutant in surface waters, due to its role in governing the transfer and fate of many substances, including nutrients, heavy metals, pesticides and other organic contaminants, and its influence on aquatic ecology. Therefore, catchment management strategies frequently need to include provision for the control of sediment mobilization and delivery. The sediment tracing concept provides a valuable framework for assisting the management and control of diffuse source sediment pollution by identifying the key sources and demonstrating the importance of intermediate storages and the likely impact of upstream mitigation strategies on downstream sediment and sediment associated contaminant fluxes. In this research, fine sediment sources were identified using tracing method. By field works, sediments were sampled from dam reservoir, different sources were also sampled. Fifteen tracers were first selected for tracing which are: The amounts of N, P, C, Cr, Co, Mg, K, Na, smectite, chlorite, illite, kaolinite, and two magnetic properties consisting of LOW Frequency Magnetic Susceptibility (X(LF)) and Frequency Dependent Magnetic Susceptibility (X(FD)). The samples were analyzed in the laboratory for these parameters and different statistical methods were applied to the data including Non-parametric Kruskal-Wallis Test and Stepwise Discriminant function analysis. The results provide important information on the relative importance of fine sediment sources to the reservoir sediments, which can be used to support model validation and the targeting of management and control strategies.

  2. Forest Ecosystem Processes at the Watershed Scale: Ecosystem services, feedback and evolution in developing mountainous catchments

    Science.gov (United States)

    Band, Larry

    2010-05-01

    Mountain watersheds provide significant ecosystem services both locally and for surrounding regions, including the provision of freshwater, hydropower, carbon sequestration, habitat, forest products and recreational/aesthetic opportunities. The hydrologic connectivity along hillslopes in sloping terrain provides an upslope subsidy of water and nutrients to downslope ecosystem patches, producing characteristic ecosystem patterns of vegetation density and type, and soil biogeochemical cycling. Recent work suggests that optimal patterns of forest cover evolve along these flowpaths which maximize net primary productivity and carbon sequestration at the hillslope to catchment scale. These watersheds are under significant pressure from potential climate change, changes in forest management, increasing population and development, and increasing demand for water export. As water balance and flowpaths are altered by shifting weather patterns and new development, the spatial distribution and coupling of water, carbon and nutrient cycling will spur the evolution of different ecosystem patterns. These issues have both theoretical and practical implications for the coupling of water, carbon and nutrient cycling at the landscape level, and the potential to manage watersheds for bundled ecosystem services. If the spatial structure of the ecosystem spontaneously adjusts to maximize landscape level use of limiting resources, there may be trade-offs in the level of services provided. The well known carbon-for-water tradeoff reflects the growth of forests to maximize carbon uptake, but also transpiration which limits freshwater availability in many biomes. We provide examples of the response of bundled ecosystem services to climate and land use change in the Southern Appalachian Mountains of the United States. These mountains have very high net primary productivity, biodiversity and water yields, and provide significant freshwater resources to surrounding regions. There has been a

  3. Near-surface temperature lapse rates in a mountainous catchment in the Chilean Andes

    Science.gov (United States)

    Ayala; Schauwecker, S.; Pellicciotti, F.; McPhee, J. P.

    2011-12-01

    In mountainous areas, and in the Chilean Andes in particular, the irregular and sparse distribution of recording stations resolves insufficiently the variability of climatic factors such as precipitation, temperature and relative humidity. Assumptions about air temperature variability in space and time have a strong effect on the performance of hydrologic models that represent snow processes such as accumulation and ablation. These processes have large diurnal variations, and assumptions that average over longer time periods (days, weeks or months) may reduce the predictive capacity of these models under different climatic conditions from those for which they were calibrated. They also introduce large uncertainties when such models are used to predict processes with strong subdiurnal variability such as snowmelt dynamics. In many applications and modeling exercises, temperature is assumed to decrease linearly with elevation, using the free-air moist adiabatic lapse rate (MALR: 0.0065°C/m). Little evidence is provided for this assumption, however, and recent studies have shown that use of lapse rates that are uniform in space and constant in time is not appropriate. To explore the validity of this approach, near-surface (2 m) lapse rates were calculated and analyzed at different temporal resolution, based on a new data set of spatially distributed temperature sensors setup in a high elevation catchment of the dry Andes of Central Chile (approx. 33°S). Five minutes temperature data were collected between January 2011 and April 2011 in the Ojos de Agua catchment, using two Automatic Weather Stations (AWSs) and 13 T-loggers (Hobo H8 Pro Temp with external data logger), ranging in altitude from 2230 to 3590 m.s.l.. The entire catchment was snow free during our experiment. We use this unique data set to understand the main controls over temperature variability in time and space, and test whether lapse rates can be used to describe the spatial variations of air

  4. Interaction between snowcover and climate, topography and vegetation in semi-arid mountain catchments

    Science.gov (United States)

    Marks, D.; Pomeroy, J.; Winstral, A.; Link, T.; Seyfried, M.; Essery, R.

    2005-12-01

    Mountainous regions in the semi-arid Northwestern US are snow-dominated with sparse summer precipitation. Vegetation at high altitudes in this environment is dominated by dry grass and sagebrush with small deciduous and evergreen forest patches in mid-point and lower hillslope locations of north-facing slopes. Wind direction and variations in near-surface wind fields due to topography and vegetation control snow deposition, causing tremendous spatial heterogeneity in the distribution of the snowcover and the delivery of melt water. Snow is scoured from exposed areas during and shortly after storms and deposited in drifts that develop in the lee of exposed ridges, and inward from forest edges. Vegetation cover and soil development is associated with topography and topographic effects on the wind field, in that only sites with sufficient melt-water delivery from drifts and soil moisture storage potential can sustain forests. Forests are typically found down slope from the deepest sections of snowdrifts, where a melt-water supply can replenish soil moisture but where the persistence of snowcover into summer does not impede forest growth. Forest canopies diminish the energy available for melt by reducing turbulent transfer, increasing incoming longwave and reducing incoming shortwave. Hence, snowcover persistence is greatly increased by forest cover - this reduces the growing season and potential evapotranspiration demand over non-forested sites. In contrast, sparsely-vegetated, exposed areas of mountain catchments accumulate less snow, and that snow melts earlier and faster than in forested areas. These hydro-ecological characteristics are very dependent on the snow regime, for instance snow transport is substantial and primarily from one direction resulting in persistent locations for large snow drifts and a relatively reliable water supply for soil development and plant growth. Transport of snow primarily to the north-facing slopes delivers melt-water to sites that

  5. Towards seasonal hydrological forecasting in mountain catchments: preliminary results from the APRIL project

    Science.gov (United States)

    Pistocchi, Alberto; Mazzoli, Paolo; Bagli, Stefano; Notarnicola, Claudia; Pasolli, Luca

    2013-04-01

    The APRIL project aims at addressing the long term quantitative prediction of monthly discharge from mountain catchments and setting up a system which can then be used operationally. More specifically, its objectives are: - To investigate the potential of EO products (snow cover extent, vegetation and soil moisture statust) and weather/climatic variables for the prediction of water streamflow from mountain catchments - To develop a robust methodology for the long term quantitative forecast of montly discharge from EO and weather/climatic data - To build a fully operational system for seasonal hydrological forecasting. This contribution illustrates the general concept of the project as well as some preliminary results. Water discharge in mountain catchments is physically related to antecedent snow cover and climatology (precipitation, temperature). Other factors may play a role, such as vegetation/soil status and topography. Historical discharge measurements and earth observation (EO) data are a valuable source for inferring the quantitative relationship between the discharge and its predictors using appropriate techniques. The prediction is based on the Support Vector Regression (SVR)technique, a state of the art machine learning regression method with good intrinsic generalization ability and robustness. In the contribution we present and discuss results of a preliminary analysis on water discharge prediction ( with lead time of 1 to 3 months) in South Tyrol, Italy. Despite the use of a limited set of predictors (among which mainly snow cover area), the results are encouraging. The analysis is in the process of being extended at different spatial scales, which will give the possibility to investigate different aspects of the problem and develop different prediction systems; by updating on the current developments, the contribution discusses also perspectives and current limitations towards the set up of a fully operational seasonal hydrological forecasting system

  6. Temporal and spatial changes in dissolved organic carbon concentration and fluorescence intensity of fulvic acid like materials in mountainous headwater catchments

    Science.gov (United States)

    Terajima, Tomomi; Moriizumi, Mihoko

    2013-02-01

    SummaryDissolved organic carbon (DOC) such as humic substances are key to understanding the aquatic environment in catchments, because they, containing a large number of phenolic and carboxylic acid groups, adsorb many kinds of inorganic materials and also affect nutrition and carbon transport in catchments. To understand the detailed DOC dynamics, we conducted hydrological observations at mountainous headwater catchments dominated by different vegetation types (planted evergreen coniferous forest of 1.29 ha and natural deciduous broadleaf forest of 1.28 ha). The relationship between DOC concentrations and fluorescence intensity of fulvic acid-like materials (F-FAM) were positively correlated in both catchments but different between soil extracts, baseflow, and near surface flow represented by biomat flow. The ratios of change in F-FAM to that in DOC concentration (F-FAM/DOC) were higher in the baseflow (about 6 in both catchments) and lower in the soil extracts (about 4.5 in both catchments, respectively). However, the relationship in stormflow was distributed between the trends of baseflow and soil extracts. The higher F-FAM/DOC in baseflow may thus indicate that DOC (and FAM) in groundwater discharge mainly contributed to the stream flow, and the stormflow mainly reflect subsurface flow through soil during most rainstorms. In contrast, a high F-FAM/DOC ratio (>6) appeared in the stormflow of both catchments especially during large storms of short duration and high intensity following a dry antecedent period. The F-FAM/DOC in biomat flow developing distinctly in the coniferous catchment was high (about 6.5). Thus, rapid shallow subsurface flow through the biomat or near-surface of slopes might explain the unique transport dynamics of DOC and FAM in stormflows with the high F-FAM/DOC ratio. These results imply that the DOC and FAM relationship responds variably depending on both the distribution of soil organic matter and rainwater flow paths in steep slopes as

  7. Effect of meteorological forcing and snow model complexity on hydrological simulations in the Sieber catchment (Harz Mountains, Germany)

    Science.gov (United States)

    Förster, K.; Meon, G.; Marke, T.; Strasser, U.

    2014-11-01

    Detailed physically based snow models using energy balance approaches are spatially and temporally transferable and hence regarded as particularly suited for scenario applications including changing climate or land use. However, these snow models place high demands on meteorological input data at the model scale. Besides precipitation and temperature, time series of humidity, wind speed, and radiation have to be provided. In many catchments these time series are rarely available or provided by a few meteorological stations only. This study analyzes the effect of improved meteorological input on the results of four snow models with different complexity for the Sieber catchment (44.4 km2) in the Harz Mountains, Germany. The Weather Research and Forecast model (WRF) is applied to derive spatial and temporal fields of meteorological surface variables at hourly temporal resolution for a regular grid of 1.1 km × 1.1 km. All snow models are evaluated at the point and the catchment scale. For catchment-scale simulations, all snow models were integrated into the hydrological modeling system PANTA RHEI. The model results achieved with a simple temperature-index model using observed precipitation and temperature time series as input are compared to those achieved with WRF input. Due to a mismatch between modeled and observed precipitation, the observed melt runoff as provided by a snow lysimeter and the observed streamflow are better reproduced by application of observed meteorological input data. In total, precipitation is simulated statistically reasonably at the seasonal scale but some single precipitation events are not captured by the WRF data set. Regarding the model efficiencies achieved for all simulations using WRF data, energy balance approaches generally perform similarly compared to the temperature-index approach and partially outperform the latter.

  8. Monitoring Riverbank Erosion in Mountain Catchments Using Terrestrial Laser Scanning

    Directory of Open Access Journals (Sweden)

    Laura Longoni

    2016-03-01

    Full Text Available Sediment yield is a key factor in river basins management due to the various and adverse consequences that erosion and sediment transport in rivers may have on the environment. Although various contributions can be found in the literature about sediment yield modeling and bank erosion monitoring, the link between weather conditions, river flow rate and bank erosion remains scarcely known. Thus, a basin scale assessment of sediment yield due to riverbank erosion is an objective hard to be reached. In order to enhance the current knowledge in this field, a monitoring method based on high resolution 3D model reconstruction of riverbanks, surveyed by multi-temporal terrestrial laser scanning, was applied to four banks in Val Tartano, Northern Italy. Six data acquisitions over one year were taken, with the aim to better understand the erosion processes and their triggering factors by means of more frequent observations compared to usual annual campaigns. The objective of the research is to address three key questions concerning bank erosion: “how” erosion happens, “when” during the year and “how much” sediment is eroded. The method proved to be effective and able to measure both eroded and deposited volume in the surveyed area. Finally an attempt to extrapolate basin scale volume for bank erosion is presented.

  9. Approximation to SOC stocks variations over time affected by land use changes in a Mediterranean mountain agricultural catchment

    Science.gov (United States)

    Lizaga, Ivan; Quijano, Laura; Gaspar, Leticia; Navas, Ana

    2017-04-01

    Land use conversion from cropland to natural vegetation can be an effective mechanism to reduce soil C losses and promote soil C recovery affecting the storage of C in soils. Understanding how anthropogenic land use changes lead to implications for soil C storage and how it affects the distribution of total carbon provide information that will support the application of best management practices to restore or maintain soil C. Agricultural abandonment is one of the most important land use changes in recent decades in Mediterranean catchments. This land use change can play a key role on ecosystems functions that, can be particularly relevant in Mediterranean mountain landscapes where soils are fragile and prone to erosion. This research aims to evaluate the effects of land use changes on SOC stocks at catchment scale. To this purpose, a total of 98 soil samples were collected on a 500 m grid in the Barués catchment (23 km2) with elevation ranges between 535 and 964 m.a.s.l and mean slope of 16°. The study area is a Mediterranean mountain ephemeral stream catchment located in the central part of the Ebro Basin in northeast Spain (4699000N 647300E) where in recent decades the abandonment of cultivated areas was the main land use change. The sampling points are distributed proportionally in function of the percentage area occupied by the different land uses to be statistically comparable. The SOC content was measured by dry combustion method with LECO equipment. A soil type map of the catchment and two land use maps were created based on two different scenarios using aerial photography for 1957 and 2010 in order to compare how land use has affected carbon storage in the catchment. Six main soil types were identified named Calcisols, Cambisols, Fluvisols, Leptosols and Regosols. The results show an important decrease (71%) of the cultivated land that in 1957 extended over 13.4 km2 whereas today only occupies 3.8 km2 while forested areas increased from 9.2 km2 in 1957

  10. Dynamics of Phosphorus export from small forested catchments in low mountain ranges in Germany

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    Julich, Stefan; Julich, Dorit; Benning, Raphael; Feger, Karl-Heinz

    2017-04-01

    Phosphorus (P) plays an important role in the nutrition of forest ecosystem. The transport of P in forest soils predominantly occurs along preferential water flow pathways bypassing large parts of the soil matrix. Therefore, rapid flow processes by preferential flow and/or during storm events may lead to significant P losses from forest soils. However only little knowledge about the dynamics, magnitude and driving processes of P exports into surface water exist. In this contribution, we present the results of two studies where two small forested catchments have been monitored for a period around 3 years. Both catchments are situated in low mountain ranges in Saxony (catchment size 21 ha) and Thuringia (catchment size 5 ha) representing medium P contents in the topsoil of 1142 mg kg-1 and 834 mg kg-1 respectively. During the regular sampling (monthly to weekly sampling frequency), the mean Total-P concentrations of 23 μg L-1(Thuringian Site) and 8 μg L-1(Saxonian Site) have been measured. However, during single storm events Total-P concentrations increased considerably with maximum concentrations of 134 μg L-1(Thuringian Site) and 203 μg L-1(Saxonian Site). Our findings indicate that during storm events, especially after longer dry periods, significant amounts of phosphorus can be exported from forest ecosystems. Comparison of discharge-concentration patterns of Total-P, Nitrogen and DOC, as well as dye tracer experiments, suggest that preferential flow along biopores and stone surfaces, and the interface between mineral soil and litter layer are main pathways of export from forests. For the site in Saxony we calculated mean annual export rates of 32.8 to 33.5 g ha-1 a-1 based on the weekly sampling with different load calculation methods (flow weighted methods up to linear regression models). If the events are included into the annual load calculation the mean annual export fluxes increase from 47.8 to 58.6 g ha-1 a-1 based on the different load calculation

  11. Snow covers detection using terrestrial photography. Application to a mountain catchment in Alps region (France).

    Science.gov (United States)

    Barth, Thierry; Saulnier, Georges-Marie; Malet, Emmanuel

    2010-05-01

    In August 2005, a significant mudflow leaded to major impacts damages at the Sainte-Agnes village located downstream the Vorz torrent (35 km2, elevations ranging from 1248m and 2977m, Alps region, France). To meet the demand of populations and civil authorities a research program was launched to both monitor and model these regions to help to quantify water resources and vulnerability to such hazardous events, including their probable evolutions do to climatic changes. This communication focuses on one of the several forcing variables of the water cycle in mountainous regions: the snow covering. Indeed, its controls a significant part of the future available water resources and may strongly interact with liquid precipitations during snow melting season. Usual sensors such as remote sensing cannot easily quantify accurately the snow covering for small mountainous catchment at hydrological models spatial and temporal resolutions (typically Dx pictures every 2-3 hours from 8.00am to 8.00pm. Thus, a lot of data on snow covering are acquired at a minimal costs. The first step of this technique is to place the cameras at "optimal location", i.e. able to see a large surface of the catchment with various elevations and aspects. This position must also be reached by direct solar radiation to recharge the embedded solar panel. A 2 or 3 hours sampling time-step was chosen for pictures shots (depending to available energy and memory capacity of camera). Indeed it allows observing all the day and offers an accurate sampling of the melting period. First major difficulty of this technique is the retro mapping of the 2D pictures from the camera on the 3D Digital Terrain Model to distribute the snow covering by elevation and aspects. The second difficulty is to automatically distinguish the snow from other meteorological "white" objects (fog, clouds, etc.) taking into account for the very various luminosity and cloud covers conditions. To make the 2D to 3D conversion, the camera

  12. A mountain environmental virtual observatory (Mountain-EVO) to support participatory monitoring in a network of Andean catchments

    Science.gov (United States)

    Buytaert, Wouter; Ochoa Tocachi, Boris; De Bievre, Bert; Zulkafli, Zed

    2015-04-01

    The tropical Andes are a hotspot of environmental change. The combination of dramatic land-use change with global climate change, demographic growth, and increasing water demand is causing extreme pressures on water resources. This is of particular concern to rural upland communities. They are facing a double challenge of maintaining their own livelihoods with dwindling natural resources, and at the same time supporting downstream ecosystem services such as a well buffered stream flow and good water quality. This challenge is complicated further by the acute lack of data on the hydrological functioning of Andean catchments. The factors controlling their hydrological response are extremely variable in space and time, including meteorological forcing, land cover types, soil properties and geology. This makes it very difficult to predict accurately the impact of human activities such as land use, ecosystem management, and watershed investments. Such predictions are essential for policy-making and sustainable ecosystem management. To tackle the issue of hydrological data scarcity in the tropical Andes, an initiative was set up to implement a network of hydrological monitoring of upland catchments in a pairwise fashion. Using a trading-space-for-time approach, the initiative intends to use these data to improve predictions about the impact of land-use changes and other ecosystem management practices on the hydrological response. Currently, over 25 catchments are being monitored for precipitation and streamflow in 9 sites located in Bolivia, Peru, Ecuador, and Venezuela. The sites are supported by local stakeholders and communities in a participatory monitoring scheme that otherwise would be impractical or prohibitively expensive. To overcome the technical challenges of monitoring hydrological variables in remote mountain areas, the initiative has set up a web-based infrastructure to support local technicians and stakeholders. Additionally, using open data standards such

  13. Modeling flash floods in ungauged mountain catchments of China: A decision tree learning approach for parameter regionalization

    Science.gov (United States)

    Ragettli, S.; Zhou, J.; Wang, H.; Liu, C.; Guo, L.

    2017-12-01

    Flash floods in small mountain catchments are one of the most frequent causes of loss of life and property from natural hazards in China. Hydrological models can be a useful tool for the anticipation of these events and the issuing of timely warnings. One of the main challenges of setting up such a system is finding appropriate model parameter values for ungauged catchments. Previous studies have shown that the transfer of parameter sets from hydrologically similar gauged catchments is one of the best performing regionalization methods. However, a remaining key issue is the identification of suitable descriptors of similarity. In this study, we use decision tree learning to explore parameter set transferability in the full space of catchment descriptors. For this purpose, a semi-distributed rainfall-runoff model is set up for 35 catchments in ten Chinese provinces. Hourly runoff data from in total 858 storm events are used to calibrate the model and to evaluate the performance of parameter set transfers between catchments. We then present a novel technique that uses the splitting rules of classification and regression trees (CART) for finding suitable donor catchments for ungauged target catchments. The ability of the model to detect flood events in assumed ungauged catchments is evaluated in series of leave-one-out tests. We show that CART analysis increases the probability of detection of 10-year flood events in comparison to a conventional measure of physiographic-climatic similarity by up to 20%. Decision tree learning can outperform other regionalization approaches because it generates rules that optimally consider spatial proximity and physical similarity. Spatial proximity can be used as a selection criteria but is skipped in the case where no similar gauged catchments are in the vicinity. We conclude that the CART regionalization concept is particularly suitable for implementation in sparsely gauged and topographically complex environments where a proximity

  14. What affects the nitrogen retention in Tatra Mountains lakes' catchments in Poland?

    Directory of Open Access Journals (Sweden)

    D. Rzychoń

    2008-03-01

    Full Text Available The study of acidification and recovery of two lakes situated in the Polish Tatra Mountains, exposed to similar deposition of acidic substances but differing in altitude, catchment morphology, hydrology, and biodiversity is presented. Measurements were performed in 1992–1996 and 2001–2005. Simultaneously, research on the atmospheric deposition was carried out. The following physical and chemical parameters in lake water and precipitation were measured: pH, conductivity (K25, Ca2+, Mg2+, Na+, K+, NH4+, SO42−, NO3, Cl and alkalinity. Distinct changes in the chemical composition of precipitation were observed over 14 years (1992–2005. During this time the sulphate concentration decreased significantly, and the concentration of hydrogen ions in precipitation decreased at an average rate of 2.23 meq/m3/yr. There was no significant change in nitrate, ammonium or total nitrogen deposition. The chemical composition of water of both lakes changed significantly and showed signs of chemical recovery with decreases in sulphate concentration and increases in acid neutralising capacity. The concentration of base cations declined. Despite the lack of clear trends in nitrogen deposition, a statistically significant drop in concentration was observed in the two lakes. A significant increase of about 15% in the retention of nitrogen compounds in both catchments occurred. An improvement in nitrogen saturation status in both catchments was observed. This probably resulted mainly from decreasing acidification and global warming which prolongs the vegetative period, changes plant species composition and increases the microbiological activity of soil.

  15. Clustering sediment connectivity maps to characterize surface morphologies in mountain catchments

    Science.gov (United States)

    Crema, Stefano; Bossi, Giulia; Trevisani, Sebastiano; Marchi, Lorenzo; Cavalli, Marco

    2017-04-01

    In mountain environments the mutual interaction between structural elements and surface processes is one of the major driver of landscape evolution. Surface morphology, as a result of this interaction, carries important information to characterize the active structure-process mutual dynamics. For this reason, it is important to derive as much information as possible from surface analysis techniques. In the present work, we apply a clustering technique to analyze the information embedded in a geomorphometric indicator. We consider a sediment connectivity index and its spatial distribution, to seek for homogeneous morphodynamics units. The selected index carries DTM-related information on slope, flow paths (flow directions, drainage area, flow path length) and surface roughness, thus being a good candidate to sum up surface morphologies information. Furthermore, considering the connectivity index spatial distribution in the clustering technique allows for the selection of contiguous and similarly behaving areas. The effectiveness of the approach is analyzed in selected alpine areas featuring a wide spectrum of both morphological features and active processes. Field surveys have confirmed the usefulness of the resulting clusters, which have proved capable of detecting consistent morphodynamics units within the catchment. The proposed method arranges for valuable information that can be exploited to set and optimize priorities of intervention and landscape management. The clusters are proposed as a tool to better depict the catchment spatial organization, highlighting those consistent morphological units that behave similarly. In this way, the presented approach is meant to facilitate landscape zonation and prioritization for an improved sediment management and environmental planning.

  16. Causal Relationships Among Time Series of the Lange Bramke Catchment (Harz Mountains, Germany)

    Science.gov (United States)

    Aufgebauer, Britta; Hauhs, Michael; Bogner, Christina; Meesenburg, Henning; Lange, Holger

    2016-04-01

    Convergent Cross Mapping (CCM) has recently been introduced by Sugihara et al. for the identification and quantification of causal relationships among ecosystem variables. In particular, the method allows to decide on the direction of causality; in some cases, the causality might be bidirectional, indicating a network structure. We extend this approach by introducing a method of surrogate data to obtain confidence intervals for CCM results. We then apply this method to time series from stream water chemistry. Specifically, we analyze a set of eight dissolved major ions from three different catchments belonging to the hydrological monitoring system at the Bramke valley in the Harz Mountains, Germany. Our results demonstrate the potentials and limits of CCM as a monitoring instrument in forestry and hydrology or as a tool to identify processes in ecosystem research. While some networks of causally linked ions can be associated with simple physical and chemical processes, other results illustrate peculiarities of the three studied catchments, which are explained in the context of their special history.

  17. Comparison of direct outflow calculated by modified SCS-CN methods for mountainous and highland catchments in upper Vistula Basin, Poland and lowland catchment in South Carolina, U.S.A

    Science.gov (United States)

    A. Walega; A. Cupak; D.M. Amatya; E. Drozdzal

    2017-01-01

    The aim of the study is to compare direct outflow from storm events estimated using modifications of original SCS-CN procedure. The study was conducted in a mountainous catchment of Kamienica River and a highland catchment draining Stobnica River located in Upper Vistula water region, both in Poland, and a headwater lowland watershed WS80 located at the Santee...

  18. Long-term changes in the hydrological regime of high mountain Lake Morskie Oko (Tatra Mountains, Central Europe

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    Ptak Mariusz

    2017-06-01

    Full Text Available The paper discusses changes in the hydrological regime of high mountain Lake Morskie Oko located in the Tatra Mountains, in the Tatra Mountains National Park, a UNESCO biosphere reserve (MaB. According to the research conducted in the years 1971–2015, its water stages decreased by 3.5 cm·dec−1, mean annual water temperature increased by 0.3°C·dec−1 and the duration of ice phenomena and ice cover was reduced by 10 day·dec−1. No considerable changes in maximum values of ice cover thickness were recorded. Such tendencies are primarily caused by long-term changes in climatic conditions – air temperature and atmospheric precipitation. The hydrological regime of the lake was also determined by changes in land use in the lake’s catchment and its location in high mountains.

  19. Estimating the collapse of aggregated fine soil structure in a mountainous forested catchment.

    Science.gov (United States)

    Mouri, Goro; Shinoda, Seirou; Golosov, Valentin; Chalov, Sergey; Shiiba, Michiharu; Hori, Tomoharu; Oki, Taikan

    2014-06-01

    This paper describes the relationship of forest soil dryness and antecedent rainfall with suspended sediment (SS) yield due to extreme rainfall events and how this relationship affects the survival of forest plants. Several phenomena contribute to this relationship: increasing evaporation (amount of water vapour discharged from soil) due to increasing air temperature, decreasing moisture content in the soil, the collapse of aggregates of fine soil particles, and the resulting effects on forest plants. To clarify the relationships among climate variation, the collapse of soil particle aggregates, and rainfall-runoff processes, a numerical model was developed to reproduce such aggregate collapse in detail. The validity of the numerical model was confirmed by its application to the granitic mountainous catchment of the Nagara River basin in Japan and by comparison with observational data. The simulation suggests that important problems, such as the collapse of forest plants in response to decreases in soil moisture content and antecedent rainfall, will arise if air temperature continues to increase. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. An application of excess lead-210 analysis for the study of fine sediment connectivity in a Mediterranean mountain basin with badlands, the Vallcebre research catchments

    Science.gov (United States)

    Moreno de las Heras, Mariano; Gallart, Francesc; Latron, Jérôme; Martínez-Carreras, Núria; Ferrer, Laura; Estrany, Joan

    2017-04-01

    Analysis of sediment dynamics in Mediterranean environments is fundamental to basin management, particularly for mountain catchments with badlands, which affect water bodies and freshwater ecosystems. Connectivity has emerged in Environmental and Earth Sciences as an evolution of the sediment delivery concept, providing a useful framework for understanding how sediments are transferred between geomorphic zones of the catchment. This study explores the feasibility of excess lead-210 (210Pbex) to analyse sediment connectivity in a 4-km2 Mediterranean mountain basin with badlands (the Vallcebre research catchments, Eastern Pyrenees) by applying simple 210Pbex mass-balance models for hypothesis generation and experimental testing in the field. Badland surfaces in the basin are weathered by freezing during the winter and are further eroded in summer by the effect of high-intensity storms. The eroded sediments may remain deposited within the catchment streams from months to years. Application of 210Pbex balance models in our basin proposes: (i) a saw-tooth seasonal pattern of badland surface 210Pbex activities (increasing from October to May, and depleted in summer) and (ii) a downstream increase in sediment activity due to fallout lead-210 accumulation in streambed sediment deposits. Both deposited and suspended sediments collected at the Vallcebre catchments showed, in general, low sediment 210Pbex concentrations, illustrating their fresh-rock origin at the badland sites, but also hampering the understanding of sediment 210Pbex patterns due to high measurement uncertainty (particularly for sediments with d50>20µm) and to strong dependence on sediment sampling methodology. Suspended sediment 210Pbex activity reproduced the simulated seasonal activity patterns for the badland surfaces. Contrary to the in-stream transit increases of sediment 210Pbex activity that were predicted by our model simulations, fallout lead-210 concentrations in the suspended sediments decreased

  1. Impact of forest disturbance on the runoff response in headwater catchments. Case study: Sumava mountains, Czech republic

    Science.gov (United States)

    Langhammer, Jakub; Hais, Martin; Bartunkova, Kristyna; Su, Ye

    2013-04-01

    The forest disturbance and stream modifications are important phenomenon affecting the natural dynamics of erosion and sedimentation processes on montane and submontane streams. The changes in land use, land cover structure, forest cover and stream modifications, occurring in the cultural landscape have significant effect on the dynamics of fluvial processes, especially in relation to the extreme runoff events. The contribution discusses the relations between forest disturbance and fluvial dynamics, stemming from the research in Sumava Mountains, located at the border between Czech Republic and Germany, Central Europe. The study area is located in headwater region, affected by different types of forest disturbance in past three decades - bark beetle outbreak, repeated windstorms and clear-cut forest management. The streams in experimental catchments here displayed extensive dynamics of erosion and sedimentation after the extreme floods in 2002 and 2009 and were affected by artificial modifications. The analysis is based on the combination of different research techniques, including remote sensed data processing, network of automated high frequency rainfall-runoff monitoring or field survey of stream modifications and geomorphologic changes on riverbeds after extreme events. Using landsat satellite data and aerial photographs we created model of Bark beetle dispersion and clear-cutting between 1985 and 2007. This model enables to describe disturbance dynamic, which is needed for understanding of nature those processes. Next analysis of Landsat satellite data was used to detect the effect of forest disturbance on the wetness and temperature properties of land cover, affected by two significant different types of forest disturbance - bark beetle outbreak and clear cut. The rainfall-runoff analysis using multivariate geostatistical techniques was focused on experimental catchments with similar conditions of climate, physiography and topography but different type

  2. Catchment-scale distribution of radiocesium air dose rate in a mountainous deciduous forest and its relation to topography.

    Science.gov (United States)

    Atarashi-Andoh, Mariko; Koarashi, Jun; Takeuchi, Erina; Tsuduki, Katsunori; Nishimura, Syusaku; Matsunaga, Takeshi

    2015-09-01

    A large number of air dose rate measurements were collected by walking through a mountainous area with a small gamma-ray survey system, KURAMA-II. The data were used to map the air dose rate of a mountainous deciduous forest that received radiocesium from the Fukushima Dai-ichi Nuclear Power Plant accident. Measurements were conducted in a small stream catchment (0.6 km(2) in area) in August and September 2013, and the relationship between air dose rates and the mountainous topography was examined. Air dose rates increased with elevation, indicating that more radiocesium was deposited on ridges, and suggesting that it had remained there for 2.5 y with no significant downslope migration by soil erosion or water drainage. Orientation in relation to the dominant winds when the radioactive plume flowed to the catchment also strongly affected the air dose rates. Based on our continuous measurements using the KURAMA-II, we describe the variation in air dose rates in a mountainous forest area and suggest that it is important to consider topography when determining sampling points and resolution to assess the spatial variability of dose rates and contaminant deposition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. A low cost strategy to monitor the expansion and contraction of the flowing stream network in mountainous headwater catchments

    Science.gov (United States)

    Assendelft, Rick; van Meerveld, Ilja; Seibert, Jan

    2017-04-01

    Streams are dynamic features in the landscape. The flowing stream network expands and contracts, connects and disconnects in response to rainfall events and seasonal changes in catchment wetness. Sections of the river system that experience these wet and dry cycles are often referred to as temporary streams. Temporary streams are abundant and widely distributed freshwater ecosystems. They account for more than half of the total length of the global stream network, are unique habitats and form important hydrological and ecological links between the uplands and perennial streams. However, temporary streams have been largely unstudied, especially in mountainous headwater catchments. The dynamic character of these systems makes it difficult to monitor them. We describe a low-cost, do-it-yourself strategy to monitor the occurrence of water and flow in temporary streams. We evaluate this strategy in two headwater catchments in Switzerland. The low cost sensor network consists of electrical resistivity sensors, water level switches, temperature sensors and flow sensors. These sensors are connected to Arduino microcontrollers and data loggers, which log the data every 5 minutes. The data from the measurement network are compared with observations (mapping of the temporary stream network) as well as time lapse camera data to evaluate the performance of the sensors. We look at how frequently the output of the sensors (presence and absence of water from the ER and water level data, and flow or no-flow from the flow sensors) corresponds to the observed channel state. This is done for each sensor, per sub-catchment, per precipitation event and per sensor location to determine the best sensor combination to monitor temporary streams in mountainous catchments and in which situation which sensor combination works best. The preliminary results show that the sensors and monitoring network work well. The data from the sensors corresponds with the observations and provides information

  4. Distribution of some trace metals in Lochnagar, a Scottish mountain lake ecosystem and its catchment.

    Science.gov (United States)

    Yang, Handong; Rose, Neil L; Battarbee, Richard W

    2002-02-21

    Anthropogenic trace metals enter the entire ecosystem of Lochnagar solely through atmospheric deposition. Trace metals, including Hg, have been monitored in atmospheric deposition and lake water, and measured in catchment vegetation, aquatic plants and zooplankton, revealing contamination levels in the ecosystem. Furthermore, 17 sediment cores were taken from different areas of the lake. Hg, Pb, Cd, Zn and Cu were analysed in all the cores, which show that the sediments have been heavily contaminated by these trace metals since the 1860s. The distribution of trace metals in the lake sediments was found to be heterogeneous, with concentrations in the surface sediments varying significantly: 110-250 ng/g, 100-360 microg/g, 39-180 microg/g, 0.3-1.9 microg/g and 8-25 microg/g for Hg, Pb, Zn, Cd and Cu, respectively. Trends in the concentration profiles for different trace metals in the same core are different, as are the trends of the profiles for the same metal in different cores. Hence, a single sediment core cannot represent the pollution history of the whole lake. As the soils and sediments contain a high proportion of plant debris and the debris has a high affinity for Hg, resulting in Hg enrichment. Hg was measured in plant debris (> 63 microm) separated from catchment soils and lake sediments. Plant debris may play an important role in storing and transferring Hg in this ecosystem.

  5. Influence Of Bedrock Geology On Elemental Fluxes In Two Forested Catchments Affected By High Acidic Deposition

    Science.gov (United States)

    Krám, P.; Hruška, J.

    1994-02-01

    Water samples have been collected from two forested catchments in the Slavkovsky les Mountains of western Bohemia, in the Czech Republic. The objective of the study was to compare and contrast elemental fluxes in two catchments with similar conditions of climate, topography, vegetation over and acidic atmospheric deposition, but very different bedrock geology. The Lysina catchment is underlain by slow-weathering leucocratic granite. Soils are podzolized brown earths and peaty gleys with small pools of exchangeable basic cations. Both soils and drainage water at Lysina are acidified by atmospheric deposition. Surface runoff was found to be dominated by sulphate and dissolved silica, accompanied by high concentrations of H+ (volume weighted pH = 3.87). Stream water also displayed extremely high concentrations of total aluminum (volume-weighted mean 66 μmol.l-1). Inorganic monomeric aluminum was the predominant aluminum fraction present, which contained mainly aquo-Al (Al3+ and fluoride complexes. The Pluhuv Bor catchment is characterized by ultramafic serpentinite and, in contrast to Lysina, soil and drainage waters have higher concentration of basic cations. Streamwater chemistry was dominated by magnesium, sulphate and silica. Stream-water at the site was not acidic (volume weighted pH = 7.25). The ratio of output/input of sulphate was similar at both catchments (1.16 for granite site and 1.07 for the serpentinite site). This pattern may be indicative of the conservative behaviour of sulphate in very different soil and bedrock environments under elevated loadings of acidic deposition.

  6. Can bed-load help to validate hydrology studies in mountainous catchment? The case study of the Roize (Voreppe, France

    Directory of Open Access Journals (Sweden)

    Piton Guillaume

    2016-01-01

    Full Text Available Larges uncertainties are attached to hazard prediction in mountain streams, because of some limitations in our knowledge of physical processes, and overall, because of the lack of measurements for validation. This is particularly true for hydrological data, making the hydrology assessment of a mountain river a very difficult task, usually associated with large uncertainties. On the other hand, contrarily to lowland rivers, bed-load in mountain streams is often trapped in mitigation-structures, such as open check dams. This study aims to take advantage of these additional information for compensating the general lack of hydrological data, in order to converge toward a comprehensive diagnosis of the catchment hydrological behavior. A hydrology and sediment transport study has been done on the Roize torrent (16.1-km2 - Voreppe - 38-FR. After a classical historical study, a regional analysis of raingauges and water-discharge-stations situated in the calcareous north Pre-Alps massifs of the Vercors, Chartreuse and Bauges has been done. A catchment geomorphology study has been performed to get insight about the Roize torrential activity and sediment transport. The volumes of bed-load transported each year on average and during extreme floods have been computed using the estimated hydrology. The good bed-load predictions compare to the volume dredged in the Voreppe sediment trap are considered an indirect validation of the hydrology study.

  7. Air temperature variability in a high-elevation Himalayan catchment

    NARCIS (Netherlands)

    Heynen, Martin; Miles, Evan; Ragettli, Silvan; Buri, Pascal; Immerzeel, Walter W.; Pellicciotti, Francesca

    2016-01-01

    Air temperature is a key control of processes affecting snow and glaciers in high-elevation catchments, including melt, snowfall and sublimation. It is therefore a key input variable to models of land-surface-atmosphere interaction. Despite this importance, its spatial variability is poorly

  8. Seasonal snowmelt modelling for the Sieber catchment (Harz Mountains, Germany) by means of WRF-downscaled analysis data including different process parameterizations for microphysics and snowmelt

    Science.gov (United States)

    Förster, Kristian; Meon, Günter; Strasser, Ulrich

    2014-05-01

    Physically based snowmelt modelling at the catchment scale requires adequate strategies to derive basin scale meteorological data fields. These meteorological data fields must fulfil two major requirements for distributed hydrological modelling with a focus on snowmelt and flood prediction: (i) high spatial and temporal resolution, and (ii) all surface variables including precipitation, temperature, humidity, wind speed, and radiation have to be physically consistent in space and time. Local atmospheric models using atmospheric (re-) analysis data meet these prerequisites. We use the Weather Research and Forecast Model (WRF) and NCEP analysis data to derive hourly meteorological data fields of surface meteorological variables with a spatial resolution of 1.1 km for the Sieber catchment (44 km2) in the Harz Mountains, Germany. At first, the performance of several model runs including three different downscaling approaches and four different microphysics parameterizations is evaluated for the winter season 2005/06 using observations from the station network. Then we carry out the hydrological simulations with the hydrological modelling system PANTA RHEI including four independent snowmelt parameterizations. The passively coupled modelling system consisting of WRF and PANTA RHEI performed well (r > 0.8) which holds also for an independent validation period. In conclusion it can be stated that local atmospheric models are suitable tools to provide boundary conditions respectively meteorological data fields for snowmelt modelling at the catchment scale. The presented approach can also be useful for water management in ungauged basins.

  9. A Top-down soil moisture and sap flux sampling design to capture the effect of inter-annual climate variability on ecohydrology in mountain catchments

    Science.gov (United States)

    Son, K.; Tague, C.

    2010-12-01

    Soil moisture in mountain catchments is highly spatial heterogeneous due to steep topographic gradients, complex soil and vegetation patterns and seasonally varying energy and precipitation inputs. In an idealized setting, a randomized soil moisture sampling design with high spatial frequency can be used to resolve the spatial heterogeneity of soil moisture at catchment scales. However, this bottom-up approach is constrained by the feasibility of high frequency measurements particularly in mountain environments with limited accessibility. Thus, in these mountain environments, an alternative, top-down approach is often needed. In this study, we propose the top-down approach sampling design of soil moisture and sapflux measurement based on an ecohydrologic model and clustering analysis. The sampling strategy is explicitly designed to capture the effect of inter-annual climate variability on ecohydrolgy response of mountain catchments located in King River Experiment Watersheds, Sierra National Forest. The ecohydrolgic model (RHESSys model) is calibrated with existing collected data sets including snow depth, soil moisture, sapflux, evapotranspiration from a flux tower and streamflow. The model is used to generate spatial-temporal patterns of snow accumulation and melt, soil moisture and transpiration and compute inter-annual mean and coefficient of variation of five hydrologic similarity indices. Similarity indices are chosen to reflect seasonal trajectories of snowmelt, root-zone soil moisture storage and evapotranspiration. Clustering analysis, using Partitioning Around Medoid (PAM), is used to partition the watershed based on these similarity indices. For the Kings River Experimental Watersheds, clustering distinguished six clusters and a representative plot per cluster. These results were used to identify additional strategic sampling points within the watershed. For each of these points, we installed soil moisture sensors (5TE) at the two depths (30m and 90m

  10. A long-term data set for hydrologic modeling in a snow-dominated mountain catchment

    Science.gov (United States)

    An hourly modeling data set is presented for the water years 1984 through 2008 for a snow-dominated headwater catchment. Meteorological forcing data and GIS watershed characteristics are described and provided. The meteorological data are measured at two sites within the catchment, and include pre...

  11. Geochemical responses of forested catchments to bark beetle infestation: Evidence from high frequency in-stream electrical conductivity monitoring

    Science.gov (United States)

    Su, Ye; Langhammer, Jakub; Jarsjö, Jerker

    2017-07-01

    Under the present conditions of climate warming, there has been an increased frequency of bark beetle-induced tree mortality in Asia, Europe, and North America. This study analyzed seven years of high frequency monitoring of in-stream electrical conductivity (EC), hydro-climatic conditions, and vegetation dynamics in four experimental catchments located in headwaters of the Sumava Mountains, Central Europe. The aim was to determine the effects of insect-induced forest disturbance on in-stream EC at multiple timescales, including annual and seasonal average conditions, daily variability, and responses to individual rainfall events. Results showed increased annual average in-stream EC values in the bark beetle-infected catchments, with particularly elevated EC values during baseflow conditions. This is likely caused by the cumulative loading of soil water and groundwater that discharge excess amounts of substances such as nitrogen and carbon, which are released via the decomposition of the needles, branches, and trunks of dead trees, into streams. Furthermore, we concluded that infestation-induced changes in event-scale dynamics may be largely responsible for the observed shifts in annual average conditions. For example, systematic EC differences between baseflow conditions and event flow conditions in relatively undisturbed catchments were essentially eliminated in catchments that were highly disturbed by bark beetles. These changes developed relatively rapidly after infestation and have long-lasting (decadal-scale) effects, implying that cumulative impacts of increasingly frequent bark beetle outbreaks may contribute to alterations of the hydrogeochemical conditions in more vulnerable mountain regions.

  12. Evaluation of soil erosion as a basis of sediment yield in mountainous catchments: a preliminary study in the River Douro Basin (Northern Portugal)

    Science.gov (United States)

    Reis, Anabela; Martinho Lourenço, José M.; Parker, Andrew; Alencoão, Ana

    2013-04-01

    The River Corgo drains a meso-scale mountainous rural catchment with an area of 295 km2, underlain by crystalline rocks, in a temperate climate, which integrates the transboundary River Douro Basin, in the northeast of Portugal. A geochemical survey on oxic fluvial sediments of the river network shows considerable contents of metals associated to the finer particles (account the hydrological pattern of the catchment, the seasonal and spatial variability of metal contents associated to the sediments suggests that the control of metal in the sediments by their mineralogical, geochemical and physical properties is governed primarily at the level of the basin soils system, especially in the Wet Period, when the sediments are frequently remobilised (Reis, 2010). Although the soil particles are a common pathway of transport and entrance of metals in the fluvial network by runoff derived erosion, this mechanism is naturally more marked in mountainous catchments. Modelling sediment and adsorbed contaminant transport within catchments can help to identify possible contaminant sources, as well as to estimate the delivered quantities of eroded material and associated contaminants. In catchments with the described morphological features, monitoring the transport of sediments poses some issues concerning: (a) the low mass yield of suspended sediment from river water, under low-flow conditions; (b) the maintenance of the sediment sampler's devices in the streams, in periods of high-flow or storm events. This study describes the preliminary results of a GIS-based mass balance model of overland sediment transport to the River. The erosion, the first step of sediment transport, was estimated by an empirical model - The Universal Soil Loss Equation (USLE). The objective was to construct a GIS based potential soil loss spatial index model and posteriorly estimate the sediment yield for different locations within the catchment. The R factor was obtained from the literature; K factor

  13. Simulating shifting vertical and lateral flow path conditions in periglacial cover beds of a small-scale low mountainous catchment

    Science.gov (United States)

    Bestian, Konrad; Kraft, Philipp; Breuer, Lutz

    2017-04-01

    Periglacial cover beds are widely spread in European low mountain regions. This concept is based on three main types of sedimentary layers differing in texture properties: The main layer containing silty material (aeolian loess sedimentation), the basal layer containing gravel and decayed bedrock material (frost weathering of bedrock) and sometimes the intermediate layer in between containing mixed material from main and basal layer. Each layer type is characterized by specific hydraulic properties related to the climatic conditions during sedimentation. Recent research shows a shifting effect on runoff generation depending on the water content of the periglacial layers. Under low water content the basal layer impedes vertical flow whereas at high water content it becomes a preferential flow path for interflow. Reproducing these shifting vertical and lateral flow path effects will increase the credibility of rainfall-runoff models. The objective of this work was to implement these shifting effects in runoff modelling. We used the Catchment Modeling Framework (CMF) as modular toolkit. First we created a hillslope model to reproduce the effect of shifting flow path. Secondly, we built a semi-distributed catchment runoff model using Hydrological Response Units (HRU) defined by expert-knowledge based on topography, land use and groundwater information. The model was set up in a way that it provides the possibility to implement shifting vertical and lateral flow paths in later model runs. We performed several field experiments in the small-scale agricultural Schwingbach observatory (1.28 km2 AEO, Hessen, Germany) to gain expert-knowledge. For instance, we identified the spatial distribution of periglacial cover beds, measured hydraulic soil properties and installed 13 piezometers. We further ran conductivity tests of the groundwater body in the piezometer using slug and bail tests. Climate data were used as forcing data and discharge data for calibration and validation

  14. Comparing erosion rates in burnt forests and agricultural fields for a mountain catchment in NW Iberia

    Science.gov (United States)

    Nunes, João Pedro; Marisa Santos, Juliana; Bernard-Jannin, Léonard; Keizer, Jan Jacob

    2013-04-01

    A large part of northwestern Iberia is nowadays covered by commercial forest plantations of eucalypts and maritime pines, which have partly replaced traditional agricultural land-uses. The humid Mediterranean climate, with mild wet winters and warm dry summers, creates favorable conditions for the occurrence of frequent and recurrent forest fires. Erosion rates in recently burnt areas have been the subject of numerous studies; however, there is still a lack of information on their relevance when compared with agricultural erosion rates, impairing a comprehensive assessment of the role of forests for soil protection. This study focuses on Macieira de Alcoba, head-water catchment in the Caramulo Mountain Range, north-central Portugal, with a mixture of agricultural fields (mostly a rotation between winter pastures and summer cereals) on the lower slopes and forest plantations (mostly eucalypts) on the upper slopes. Agricultural erosion in this catchment has been monitored since 2010; a forest fire in 2011 presented an opportunity to compare post-fire and agricultural erosion rates at nearby sites with comparable soil and climatic conditions. Erosion rates were monitored between 2010 and 2013 by repeated surveys of visible erosion features and, in particular, by mapping and measuring rills and gullies after important rainfall events. During the 2011/2012 hydrological year, erosion rates in the burnt forest were two orders of magnitude above those in agricultural fields, amounting to 17.6 and. 0.1 Mg ha-1, respectively. Rills were widespread in the burnt area, while in the agricultural area they were limited to a small number of fields with higher slope; these particular fields experienced an erosion rate of 2.3 Mg ha-1, still one order of magnitude lower than at the burnt forest site. The timing of the erosion features was also quite distinct for the burnt area and the agricultural fields. During the first nine months after the fire, rill formation was not observed in

  15. Performance of Two Hydrological Models in Predicting Daily Flow under a Climate Change Scenario for Mountainous Catchments in Northwestern Costa Rica

    Directory of Open Access Journals (Sweden)

    César D. Jiménez-Rodríguez 

    2015-08-01

    Full Text Available Tropical mountain regions contain the main headwaters of important rivers in Central America. We selected 2 contrasting catchments located in a mountainous region to evaluate the precision of daily flow estimates based on the Hydrological Land Use Change (HYLUC and Nedbør-Afstrømnings Model (NAM hydrological models. A second objective was to simulate the impact of expected climate change for the year 2050 on stream flows and seasonal distribution of rainfall. We studied the catchments of the Tempisquito and Cucaracho streams, located in the Guanacaste volcanic mountain range of Costa Rica, from April 2008 to October 2010. Modeling of discharge using the NAM and HYLUC models suggested difficulties in their calibration due to intrinsic catchment characteristics because of their volcanic origin. The climate change scenario applied in both catchments depicted a strong reduction in discharge. However, the Cucaracho catchment, on the Caribbean slope, is predicted to experience a smaller reduction in discharge than the Tempisquito catchment, located on the Pacific slope.

  16. Understanding triggers and dynamics of wood-laden flash floods in mountain catchments: examples from the Zulg River (Switzerland)

    Science.gov (United States)

    Ruiz-Villanueva, Virginia; Galatiotto, Niccolo; Bürkli, Livia; Stoffel, Markus

    2017-04-01

    Mountain rivers are prone to flash floods, and in forested basins, large quantities of wood can be moved and transported long distances downstream during such events. Under certain circumstances, congested transport of wood may result in wood-laden flows in which a large number of logs form a mass moving together with the flow and thus alter its dynamics. This process could significantly increase the flood hazard and risk, however, the knowledge about the formation of these wood-laden flows is still very limited. The Zulg River (23 km long and 89 km2 drainage area) is located in the Swiss Prealps in the canton of Bern (Switzerland). In the Zulg catchment, heavy local precipitation usually leads to a fast reaction of the water level downstream and very often flash floods are transporting significant volume of wood. There are several bridges crossing the river at the area of Steffisburg and downstream of this town the Zulg flows into the Aare River that crosses the city of Bern few kilometres downstream. Therefore, a better understanding of these processes will help to improve the flood risk management of the region. In this work we are analysing four recent floods (i.e., 2012, 2013, 2015 and 2016) with significant wood transport and the goal is to decipher the triggering and formation of the wood-laden flash floods. We collected aerial pictures from before and after each flood to map the pre- and post-flood conditions and mapped riverscape units, landslides and the wood logs and jams already deposited along the river channel. The forest stand volumes recruited during the events is analysed based on the land use maps available and provided by the Cantonal Forest Service. We also analysed movies taken by witnesses during these flash flood events, which may potentially provide highly valuable information (i.e., the amount and type of wood in motion or what was roughly the velocity and direction of the water) to quantify wood fluxes. However, the usage of these home

  17. Novel MixSIAR fingerprint model implementation in a Mediterranean mountain catchment

    Science.gov (United States)

    Lizaga, Ivan; Gaspar, Leticia; Blake, William; Palazón, Leticia; Quijano, Laura; Navas, Ana

    2017-04-01

    Increased sediment erosion levels can lead to degraded water and food quality, reduced aquatic biodiversity, decrease reservoir capacity and restrict recreational usage but determining soil redistribution and sediment budgets in watersheds is often challenging. One of the methods for making such determinations applies sediment fingerprinting methods by using sediment properties. The fingerprinting procedure tests a range of source material tracer properties to select a subset that can discriminate between the different potential sediment sources. The present study aims to test the feasibility of geochemical and radioisotopic fingerprint properties to apportion sediment sources within the Barués catchment. For this purpose, the new MixSIAR unmixing model was implemented as statistical tool. A total of 98 soil samples from different land cover sources (Mediterranean forest, pine forest scrubland, agricultural and subsoil) were collected in the Barués catchment (23 km2). This new approach divides the catchment into six different sub-catchments to evaluate how the sediment provenance varies along the river and the percentage of its sources and not only the contribution at the end. For this purpose, target sediments were collected at the end of each sub-catchment to introduce the variation along the entire catchment. Geochemistry and radioisotopic activity were analyzed for each sample and introduced as input parameters in the model. Percentage values from the five sources were different along the different subcatchments and the variations of all of them are summarized at the final target sample located at the end of the catchment. This work represents a good approximation to the fine sediment provenance in Mediterranean agricultural catchments and has the potential to be used for water resource control and future soil management. Identifying sediment contribution from different land uses offers considerable potential to prevent environmental degradation and the

  18. Long-term water temperature reconstructions from mountain lakes with different catchment and morphometric features

    National Research Council Canada - National Science Library

    Luoto, Tomi P; Nevalainen, Liisa

    2013-01-01

    .... We reconstruct summer water temperatures from three climatically sensitive mountain lakes in Austria using paleolimnological methods aiming to examine long-term thermal dynamics and lakes' responses...

  19. REGIONAL ANALYSIS OF INORGANIC NITROGEN YIELD AND RETENTION IN HIGH-ELEVATION ECOSYSTEMS OF THE SIERRA NEVADA AND ROCKY MOUNTAINS

    Science.gov (United States)

    Yields and retention of inorganic nitrogen (DIN) and nitrate concentrations in surface runoff are summarized for 28 high elevation watersheds in the Sierra Nevada, California and Rocky Mountains of Wyoming and Colorado. Catchments ranged in elevation from 2475 to 3603 m and from...

  20. What controls the long-term sediment flux from headwater catchments in the low mountain ranges of central Europe?

    Science.gov (United States)

    Larsen, A.; Bork, H.; Heckmann, T.; Larsen, J.

    2012-12-01

    During the Medieval Period, agricultural expansion into steeper catchments of central Europe led to a well documented increase in slope erosion. This in turn has been used to explain the apparent rapid aggradation of downstream floodplains, as well as the possible conversion of river regimes from multi-thread to meandering. However, both a long term context in which to place this period of increased erosion, and an appropriate quantification of the sediment fluxes, remain largely undetermined from these headwater catchments. In order to address some of these knowledge gaps, we examined a small (42 ha) headwater gully system in the Spessart mountains of central Germany. Detailed measurements and chronology were obtained from all major sediment sources and sinks, including the slope catena, gully thalweg, gully fan, and the floodplain of the adjacent trunk stream (Elsava River). Our results demonstrate the ability of the gully thalweg to effectively store the bulk of eroded sediment derived from slope instability during periods of diminished vegetation cover (Younger Dryas, Medieval Period). Interestingly, sediment export does not occur in our catchment until slopes are re-stabilized by vegetation, as was the case for most of the Holocene, and the last ~ 500 years, following recovery from Medieval deforestation. This suggests that whichever forcing controls vegetation removal, climate (Younger Dryas), or humans (Medieval Period), also determines slope erosion, but not the export of this sediment to downstream floodplains. Likewise, the development of sufficient vegetation cover to reduce slope sediment supply is the critical condition which determines the ability of the gully to incise, and export sediment to trunk streams. In terms of the sediment budget, the recent (last ~500 years) release of silty sediment stored in the gully thalweg (derived from Medival slope erosion) was 4.3 ± 0.32 kt. Compared to Holocene sediment flux, whose cumulative export is not greater

  1. High resolution modeling of a small urban catchment

    Science.gov (United States)

    Skouri-Plakali, Ilektra; Ichiba, Abdellah; Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel

    2016-04-01

    Flooding is one of the most complex issues that urban environments have to deal with. In France, flooding remains the first natural risk with 72% of decrees state of natural disaster issued between October 1982 and mid-November 2014. Flooding is a result of meteorological extremes that are usually aggravated by the hydrological behavior of urban catchments and human factors. The continuing urbanization process is indeed changing the whole urban water cycle by limiting the infiltration and promoting runoff. Urban environments are very complex systems due to their extreme variability, the interference between human activities and natural processes but also the effect of the ongoing urbanization process that changes the landscape and hardly influences their hydrologic behavior. Moreover, many recent works highlight the need to simulate all urban water processes at their specific temporal and spatial scales. However, considering urban catchments heterogeneity still challenging for urban hydrology, even after advances noticed in term of high-resolution data collection and computational resources. This issue is more to be related to the architecture of urban models being used and how far these models are ready to take into account the extreme variability of urban catchments. In this work, high spatio-temporal resolution modeling is performed for a small and well-equipped urban catchment. The aim of this work is to identify urban modeling needs in terms of spatial and temporal resolution especially for a very small urban area (3.7 ha urban catchment located in the Perreux-sur-Marne city at the southeast of Paris) MultiHydro model was selected to carry out this work, it is a physical based and fully distributed model that interacts four existing modules each of them representing a portion of the water cycle in urban environments. MultiHydro was implemented at 10m, 5m and 2m resolution. Simulations were performed at different spatio-temporal resolutions and analyzed with

  2. Seasonal changes in runoff generation in a small forested mountain catchment

    NARCIS (Netherlands)

    Penna, D.; van Meerveld, H.J.; Oliviero, O.; Zuecco, G.; Assendelft, R.S.; Dalla Fontana, G.; Borga, M.

    2014-01-01

    This study aimed to investigate the seasonal variability of runoff generation processes, the sources of stream water, and the controls on the contribution of event water to streamflow for a small forested catchment in the Italian pre-Alps. Hydrometric, isotopic, and electrical conductivity data

  3. Hydrological modeling of Fecal Indicator Bacteria in a tropical mountain catchment.

    Science.gov (United States)

    Kim, Minjeong; Boithias, Laurie; Cho, Kyung Hwa; Silvera, Norbert; Thammahacksa, Chanthamousone; Latsachack, Keooudone; Rochelle-Newall, Emma; Sengtaheuanghoung, Oloth; Pierret, Alain; Pachepsky, Yakov A; Ribolzi, Olivier

    2017-08-01

    The occurrence of pathogen bacteria in surface waters is a threat to public health worldwide. In particular, inadequate sanitation resulting in high contamination of surface water with pathogens of fecal origin is a serious issue in developing countries such as Lao P.D.R. Despite the health implications of the consumption of contaminated surface water, the environmental fate and transport of pathogens of fecal origin and their indicators (Fecal Indicator Bacteria or FIB) are still poorly known in tropical areas. In this study, we used measurements of flow rates, suspended sediments and of the FIB Escherichia coli (E. coli) in a 60-ha catchment in Northern Laos to explore the ability of the Soil and Water Assessment Tool (SWAT) to simulate watershed-scale FIB fate and transport. We assessed the influences of 3 in-stream processes, namely bacteria deposition and resuspension, bacterial regrowth, and hyporheic exchange (i.e. transient storage) on predicted FIB numbers. We showed that the SWAT model in its original version does not correctly simulate small E. coli numbers during the dry season. We showed that model's performance could be improved when considering the release of E. coli together with sediment resuspension. We demonstrated that the hyporheic exchange of bacteria across the Sediment-Water Interface (SWI) should be considered when simulating FIB concentration not only during wet weather, but also during the dry season, or baseflow period. In contrast, the implementation of the regrowth process did not improve the model during the dry season without inducing an overestimation during the wet season. This work thus underlines the importance of taking into account in-stream processes, such as deposition and resuspension, regrowth and hyporheic exchange, when using SWAT to simulate FIB dynamics in surface waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Quantifying uncertainties in tracer-based hydrograph separations: a case study for two-, three- and five-component hydrograph separations in a mountainous catchment

    Science.gov (United States)

    Uhlenbrook, Stefan; Hoeg, Simon

    2003-02-01

    The hydrograph separation technique using natural tracers, in which different runoff components are quantified according to their chemical signature, is a widely used method for investigating runoff generation processes at the catchment scale. The first objective of this study is to demonstrate a modified methodology for separating three and five runoff components using 18O and dissolved silica as tracers. The second is to evaluate, with an uncertainty propagation technique using Gaussian error estimators, the hydrograph separation uncertainties that arise due to different error effects.During four summer storm events, an interaction among three main runoff components having distinct dissolved silica concentrations was demonstrated for the mountainous Zastler catchment (18·4 km2, southern Black Forest Mountains, southwest Germany). The three main runoff components are surface storage (low silica, saturated and impermeable areas), shallow ground water (medium silica, periglacial and glacial drift cover), and deep ground water (high silica, crystalline detritus and hard rock aquifer). Together with the event and pre-event water fractions of surface runoff and shallow ground water runoff, five runoff components are considered in all. Pre-event water from shallow ground water storage dominated the total discharge during floods and was also important during low flows. Event water from shallow ground water was detectable only during the falling limb of a larger flood with high antecedent moisture conditions and during the peaks of three events with low antecedent moisture conditions. Runoff from surface storage is only significant during floods and can be composed of event and pre-event water. The latter reacts later and is important only during the peak of the large event with high antecedent moisture conditions. Runoff from the deeper ground water behaves quite consistently (pure pre-event water).It is demonstrated that large relative uncertainties must be considered

  5. Estimation of snow and glacier melt contribution to Liddar stream in a mountainous catchment, western Himalaya: an isotopic approach.

    Science.gov (United States)

    Jeelani, Gh; Shah, Rouf A; Jacob, Noble; Deshpande, Rajendrakumar D

    2017-03-01

    Snow- and glacier-dominated catchments in the Himalayas are important sources of fresh water to more than one billion people. However, the contribution of snowmelt and glacier melt to stream flow remains largely unquantified in most parts of the Himalayas. We used environmental isotopes and geochemical tracers to determine the source water and flow paths of stream flow draining the snow- and glacier-dominated mountainous catchment of the western Himalaya. The study suggested that the stream flow in the spring season is dominated by the snowmelt released from low altitudes and becomes isotopically depleted as the melt season progressed. The tracer-based mixing models suggested that snowmelt contributed a significant proportion (5-66 %) to stream flow throughout the year with the maximum contribution in spring and summer seasons (from March to July). In 2013 a large and persistent snowpack contributed significantly (∼51 %) to stream flow in autumn (September and October) as well. The average annual contribution of glacier melt to stream flow is little (5 %). However, the monthly contribution of glacier melt to stream flow reaches up to 19 % in September during years of less persistent snow pack.

  6. Environmental history of European high mountains

    OpenAIRE

    Galop, Didier; Catto, Norm

    2014-01-01

    International audience; This volume brings together 16 papers which investigate various aspects of high mountain areas, primarily in Europe. Dietre et al. investigated the influence of settlement in the Silv-retta Alps, Switzerland/Austria. Festi et al. combined an extensive archaeological survey and pollen analyses in the high altitudes of the € Otztal Alps to elucidate the palaeo-environmental and past cultural implications that triggered the onset and development of seasonal transhumance a...

  7. Hydrochemistry dynamics in remote mountain lakes and its relation to catchment and atmospheric features: the case study of Sabocos Tarn, Pyrenees.

    Science.gov (United States)

    Santolaria, Zoe; Arruebo, Tomas; Urieta, José Santiago; Lanaja, Francisco Javier; Pardo, Alfonso; Matesanz, José; Rodriguez-Casals, Carlos

    2015-01-01

    Increasing the understanding of high mountain lake dynamics is essential to use these remote aquatic ecosystems as proxies of global environmental changes. With this aim, at Sabocos, a Pyrenean cirque glacial lake or tarn, this study shows the main results of a morphological and catchment characterization, along with statistical analyses of its hydrochemical trends and their concomitant driving factors from 2010 to 2013. Dissolved oxygen, water temperature stratification, and its snow and ice cover composition and dynamics have been also investigated. According to morphological analyses, Sabocos can be classified as a medium-large and deep lake, having a circular contour and a long water retention time as compared to Pyrenean glacial lake average values. Sabocos hydrochemistry is mainly determined by very high alkalinity, pH and conductivity levels, and high Ca(2+), Mg(2+), and SO4(2-) content, coming from the easily weatherable limestone-dolomite bedrock. Thus, lake water is well buffered, and therefore, Sabocos tarn is non-sensitive to acidification processes. On the other hand, the main source of K(+), Na(+), and Cl(-) (sea salts) and nutrients (NH4(+), NO3(-), and phosphorous) to lake water appears to be atmospheric deposition. Primary production is phosphorous limited, and due to the N-saturation stage of the poorly developed soils of Sabocos catchment, NO3(-) is the chief component in the total nitrogen pool. External temperature seems to be the major driver regulating lake productivity, since warm temperatures boot primary production. Although precipitation might also play an important role in lake dynamics, especially regarding to those parameters influenced by the weathering of the bedrock, its influence cannot be easily assessed due to the seasonal isolation produced by the ice cover. Also, as occurs in the whole Pyrenean lake district, chemical composition of bulk deposition is highly variable due to the contribution of air masses with different origin.

  8. Wind drifted snow influence on the water and mass balance in the mountainous catchment "Modry potok", the Giant Mountains, Czech Republic.

    Science.gov (United States)

    Dvorak, I. J.; Fottova, D.; Tesar, M.; Kocianova, M.; Harcarik, J.

    2009-04-01

    There are very specific components of the water balance in the mountain headwater regions. Beside the point of cloud- and fog-water deposition it is mainly accumulation of water in the snow cover drifted into the watershed by the wind. Uneven distribution of the snow cover over the mountainous terrain is a well known phenomenon in all alpine and arctic areas. The result of this uneveness is a mosaic of microhabitats with various snow depths, different melting dates and snow free periods. Wire probes can be reliably used up to snow depths of 3 m only. To get more realistic data, two digital models using kinematic carrier phase-based GPS measurements were developed: (1) a model for snow surface data, applied at the end of winter seasons from 2000 to 2008, and (2) a model for the underlying snow free ground surface, applied after the snow melting in August 2000. These two models, overlaid in the GIS environment, have identified snow depths. For the creation of digital elevation models (DEMs), the TOPOGRID command in ArcInfo was used, which generated a grid of elevations from 3-D point, line, and polygon data. The snow depths were obtained and snow maps constructed accordingly. These "snow" results can be used for more realistic estimation of water content of snow in the watershed, distribution of snow depth during the winter seasons and define the water and mass balance more precisely. The objectives of this study were to highlight water storage in the snow-beds and show the GPS kinematic measurements as a contribution to understand more the snow accumulating and melting processes in the Modry potok catchment (2,62 km2, 1010 - 1554 m a.s.l.) in the Giant Mts. The research is supported by the Ministry of the Environment of the Czech Republic (SP/1a6/151/07) and by the Krkonose National Park Administration in Vrchlabi.

  9. Long-term water temperature reconstructions from mountain lakes with different catchment and morphometric features.

    Science.gov (United States)

    Luoto, Tomi P; Nevalainen, Liisa

    2013-01-01

    Long-term water temperature records are necessary for better understanding climate change impacts on freshwaters. We reconstruct summer water temperatures from three climatically sensitive mountain lakes in Austria using paleolimnological methods aiming to examine long-term thermal dynamics and lakes' responses to regional climate variability since the Little Ice Age. Our results indicate divergent trends for the lakes. In two of the lakes, which are located at the sunny southern slope of mountains, water temperature has increased several degrees concurrent with the observed air temperature increase. In contrast, no change is observed in the reconstructed water temperatures of a shaded lake, located at the northern slope, where also the ecological and thermal changes are most subtle. The results indicate the importance of cold water inputs, such as snowmelt and groundwater, on lakes' thermal conditions and suggest that watershed characteristics and lake stratification play a major role in defining the lake-specific thermal regime.

  10. THE ROLE OF THE HYDRO-CLIMATIC CONDITIONS IN CAUSING HIGH FLOODS IN THE SUCEVIȚA RIVER CATCHMENT

    Directory of Open Access Journals (Sweden)

    HAPCIUC OANA

    2015-03-01

    Full Text Available Located in the north-eastern part of Romania, the Suceviţa catchment has been affected in the last decade, by the most serious known high floods in the modern period of hydrological observations. The significant amounts of rainfall (260 mm in five days in 2008 and 150 mm in four days in 2010 have led to the formation of high floods that have affected large areas of land near the river course. These torrential rainfall led to the recording of maximum flows showing an increased tendency from 214 m3/s in 2007 to 467 m3/s in 2010 (reconstituted value exceeding the probability of occurrence of 0.1%. Even if the afforestation degree, at the level of the catchment and its tributaries, in the mountainous area, is over 80%, the morphometric conditions given by the average high values of the slopes (37-55‰ and also by the circularity ratio (0,60 – 0,73 generate a fast drainage of the precipitation water to the riverbeds. At the same time, the human activity increases the impact of flooding because of the activities carried out near watercourses. Flooding associated with these high floods have highlighted the vulnerability of the communities manifested by weak capacity to absorb the effects of the phenomenon and to recover after such events. Therefore, the high floods of 2008 and 2010 have caused extensive damage to the localities situated in the Sucevița river catchment.

  11. Long-term water temperature reconstructions from mountain lakes with different catchment and morphometric features

    OpenAIRE

    Luoto, Tomi; Nevalainen, Liisa

    2013-01-01

    Long-term water temperature records are necessary for better understanding climate change impacts on freshwaters. We reconstruct summer water temperatures from three climatically sensitive mountain lakes in Austria using paleolimnological methods aiming to examine long-term thermal dynamics and lakes' responses to regional climate variability since the Little Ice Age. Our results indicate divergent trends for the lakes. In two of the lakes, which are located at the sunny southern slope of mou...

  12. The response of glacier melt runoff to climate change: a glacierized catchment in Tieshan Mountains

    Science.gov (United States)

    Fang, Gonghuan; Yang, Jing; Chen, Yaning; Li, Zhi

    2017-04-01

    Water resources are sensitive to climate change for the arid inland basins, whose water originates largely from the glacierized mountains. In this study, we simulated the glacial process and then analyzed its response to future climate change in a typical Tieshan Mountains watershed - Aksu watershed. To simulate glacial process, we developed a glacial module into a semi-distributed hydrologic model and then performed multi-objective sensitivity analysis and optimization by combining observed flow data and water isotope data. The calibrated model was then used to analyze the response to climate change through future climate forcing obtained by applying BMA (Bayesian Model Averaging) technique to an ensemble of one RCM and 21-GCM simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) under RCP4.5 and RCP8.5. Results indicated that the parameters related to groundwater flow and its interaction with surface water flow are the most sensitive parameters, and glacier-related parameters are also sensitive, indicating a large part of the streamflow is recharged by glacier melt water. Runoff will overall increase in the near future but will decrease at the end of the 21st century. The combined use of different data sources sheds some sights on hydrological modelling in the Tienshan mountainous.

  13. Use of reservoir deposits to reconstruct the recent changes in sediment yields from a small granite catchment in the Yimeng Mountain region, China

    Science.gov (United States)

    Zhang, Yunqi; Long, Yi; Li, Bao; Xu, Shujian; Wang, Xiaoli; Liao, Jia

    2017-09-01

    Information on recent changes in sediment yields from small catchments provides a better understanding of temporal trends in soil loss from certain physical and human-influenced landscapes that have been subjected to recent environmental changes, and will help bridge the current knowledge gap that exists between hillslope erosion and sediment transport in rivers. The Yimeng Mountain region, characterized by alternating granite and limestone, is one of the most susceptible regions to soil erosion in northern China, and has been subjected to intensive anthropogenic activity in recent years. Soil loss from areas underlain by granite is particularly obvious, and is the main sediment source for the Yihe River. In this study, we used reservoir deposits to estimate the changes in sediment yields over the past 50 years from a small catchment underlain by granite, namely the Jiangzhuang catchment in the Yimeng Mountain region. Three cores were collected from the Jiangzhuang Reservoir in the catchment. The activities of 137Cs and 210Pbex at different depths, clay (grain size original capacity curve of the reservoir. The results indicate that the depth profiles of 137Cs, 210Pbex, clay, and SOC contents in cores from the Jiangzhuang Reservoir reflect the general history of human disturbances on the catchment over the past 50 years. The estimated SSY value from each core for each period ranged from 7.2 ± 2.7 to 23.7 ± 8.3 t ha- 1 y- 1, with a mean of 12.5 ± 4.6 t ha- 1 y- 1. SSY decreased during 1954-1972, and then showed a general tendency to increase. The temporal pattern of the sediment yield largely reflects the history of environmental change influenced by human activity in the catchment.

  14. Long-term growth and water balance predictions for a mountain ash (Eucalyptus regnans) forest catchment subject to clear-felling and regeneration.

    Science.gov (United States)

    Vertessy, R. A.; Hatton, T. J.; Benyon, R. G.; Dawes, W. R.

    1996-01-01

    We used a physically based ecohydrological model to predict the water balance and growth responses of a mountain ash (Eucalyptus regnans F. Muell.) forest catchment to clear-felling and regeneration. The model, Topog-IRM, was applied to a 0.53 km(2) catchment for a 3-year pretreatment period, and a 20-year period following clear-felling and reseeding of 78% of the catchment area. Simulations were evaluated by comparing observed and predicted streamflows, rainfall interception and soil water values. The model faithfully simulated observed temporal patterns of overstory live stem carbon gain and produced a leaf area trajectory consistent with field observations. Cumulative throughfall was predicted within 1% of observations over an 18-year period. Over a 4-year period, predicted soil water storage in the upper 1.5 m of soil agreed well with field observations. There was fair correspondence between observed and predicted daily streamflows, and the model explained 76% of the variation in monthly flows. Over the 23-year simulation period, the model overpredicted cumulative streamflow by 6%. We argue that there is a useful role for physically based ecohydrological models in the management of mountain ash forest catchments that cannot be satisfied by simple empirical approaches.

  15. Rainfall-runoff modelling using different estimators of precipitation data in the Carpathian mountain catchments (South Poland)

    Science.gov (United States)

    Kasina, Michal; Ziemski, Michal; Niedbala, Jerzy; Malota, Agnieszka

    2013-04-01

    Precipitation observations are an essential element of flood forecasting systems. Rain gauges, radars, satellite sensors and forecasts from high resolution numerical weather prediction models are a part of precipitation monitoring networks. These networks collect rainfall data that are further provided to hydrological models to produce forecasts. The main goal of this work is to assess the usage of different precipitation data sources in rainfall-runoff modelling with reference to Flash Flood Early Warning System. STUDY AREA Research was carried out in the upper parts of the Sola and Raba river catchments. Both of the rivers begin their course in the southern part of the Western Beskids (Outer Eastern Carpathians; southern Poland). For the purpose of this study, both rivers are taken to comprise the catchments upstream of the gauging stations at Zywiec (Sola) and Stroza (Raba). The upper Sola river catchment encompasses an area of 785 sq. km with an altitude ranging from 342 to 1236 m above sea level, while the Raba river catchment occupies an area of 644 sq. km with an altitude ranging from 300 to 1266 m above sea level. The catchments are underlain mainly by flysch sediments. The average annual amount of precipitation for the Sola River catchment is between 750 and 1300 mm and for the Raba river catchment is in the range of 800-1000 mm. METHODS AND RESULTS This work assesses the sensitivity of a lumped hydrological model DHI's Nedbør-Afrstrømnings-Model (NAM) to different sources of rainfall estimates: rain gauges, radar and satellite as well as predicted precipitation amount from high resolution numerical weather prediction models (e.g. ALADIN). The main steps of validation procedure are: i) comparison of rain gauge data with other precipitation data sources, ii) calibration of the hydrological model (using historical, long time series of rain gauge data treated as "ground truth"), iii) validation using different precipitation data sources as an input, iii

  16. Is There Synchronicity in Nitrogen Input and Output Fluxes at the Noland Divide Watershed, a Small N-Saturated Forested Catchment in the Great Smoky Mountains National Park?

    Directory of Open Access Journals (Sweden)

    H. Van Miegroet

    2001-01-01

    Full Text Available High-elevation red spruce [Picea rubens Sarg.]-Fraser fir [Abies fraseri (Pursh. Poir] forests in the Southern Appalachians currently receive large nitrogen (N inputs via atmospheric deposition (30 kg N ha�1 year�1 but have limited N retention capacity due to a combination of stand age, heavy fir mortality caused by exotic insect infestations, and numerous gaps caused by windfalls and ice storms. This study examined the magnitude and timing of the N fluxes into, through, and out of a small, first-order catchment in the Great Smoky Mountains National Park. It also examined the role of climatic conditions in causing interannual variations in the N output signal. About half of the atmospheric N input was exported annually in the streamwater, primarily as nitrate (NO3-N. While most incoming ammonium (NH4-N was retained in the canopy and the forest floor, the NO3-N fluxes were very dynamic in space as well as in time. There was a clear decoupling between NO3-N input and output fluxes. Atmospheric N input was greatest in the growing season while largest NO3-N losses typically occurred in the dormant season. Also, as water passed through the various catchment compartments, the NO3-N flux declined below the canopy, increased in the upper soil due to internal N mineralization and nitrification, and declined again deeper in the mineral soil due to plant uptake and microbial processing. Temperature control on N production and hydrologic control on NO3-N leaching during the growing season likely caused the observed inter-annual variation in fall peak NO3-N concentrations and N discharge rates in the stream.

  17. Attribution of observed hydrological changes and impacts of future climate change in glacierized mountain catchments in Central Asia

    Science.gov (United States)

    Duethmann, Doris; Menz, Christoph; Vorogushyn, Sergiy; Merz, Bruno; Kriegel, David; Bolch, Tobias; Pieczonka, Tino; Farinotti, Daniel; Jiang, Tong; Su, Buda; Güntner, Andreas

    2017-04-01

    High elevation areas in Central Asia currently undergo considerable changes. Trend analyses show that discharge in two headwater catchments of the Tarim River, Northwest China, increased by more than 30% over the past decades. While many studies focus on trend detection, understanding the causes of these changes, i.e. trend attribution, may be even more important. In this study, we first demonstrate the use of a simulation-based approach for attributing the observed streamflow increase to its possible causes. In a second step, we analyze the impact of future climate scenarios for these catchments. Particular attention was given to multiobjective and multivariable calibration, including daily streamflow variability, long-term streamflow changes, annual variability of glacier and regional glacier mass changes. The hydrological model thus allows us to evaluate whether the causes for the observed changes in discharge are also consistent with these data. The hydrological model considers transient reductions in glacier area and lowering of the glacier surface elevation resulting from sustained negative glacier mass balances. For trend attribution, we compare simulations with original and detrended temperature and precipitation series. In the catchment with a lower glacierization, temperature and precipitation increases were both important for the discharge increase. In the catchment with a higher glacier cover, discharge increases are predominantly attributed to temperature increases and related increases of glacier melt, indicating that the increased discharge originates to a considerable extent from loss of glacier storage. A major advantage of the simulation-based attribution approach is seen in the fact that it relies on process-based relationships. The climate impact analysis is based on hundreds of simulations runs that consider different GCMs, emission scenarios and hydrological model parameters. By 2100, projections show a reduction in glacier area by 28 to 89

  18. Transit time of water discharges from catchments in coastal mountain of Chile

    Science.gov (United States)

    Bustamante-Ortega, Ramon; Morgenstern, Uwe; Ramirez de Arellano, Pablo

    2015-04-01

    Water quantity and quality response of forest catchments to climate and land-use change are difficult to understand and predict due to complexities of subsurface water flow paths. The main focus of forest hydrology in Chile has been the effect of canopy and soil together with rain in water availability. Groundwater, as a factor in water availability especially during dry season, has not been studied. Only a few studies have been carried out in northern Chile in a non-forestry area using the stable isotopes of the water to characterize recharge and depletion of the aquifer. We use tritium for understanding the dynamics of groundwater through small watersheds over a latitudinal gradient in the coastal range of Central Chile. The zone constitutes rapid growth plantations and a large population that depend on surface water and groundwater for drinking, agriculture, pasture and industry. The study areas have metamorphic bedrock with a Mediterranean weather, and precipitation ranging from 700-800 mm year-1 in the North (Constitución area) to 2300-2500 mm year-1 in the South (Valdivia area). The watersheds have been forested with Pinus radiata in 2003 and 1990 respectively, and flow stations were installed in 2008 by Forestal Arauco S.A. to identify the forest management impact on the water cycle. Tritium is present in meteoric water and decays through radioactive decay. In groundwater, which is separated from the tritium production source in the atmosphere, the tritium concentration decreases over time and therefore allows for determination of the residence time of the water in the groundwater system, and the lag time between recharge of the water, and discharge into the streams. Preliminary results of rain samples collected in 2014 in Constitución confirm the tritium input estimate that we made using the New Zealand input data from similar latitude, and the IAEA data (http://www-naweb.iaea.org/napc/ih/IHS_resources_gnip.html). The mean residence time of the water in

  19. Quantification of Phosphorus Exports from a Small Forested Headwater-Catchment in the Eastern Ore Mountains, Germany

    Directory of Open Access Journals (Sweden)

    Stefan Julich

    2017-06-01

    Full Text Available Phosphorus (P export from forest soils is mainly driven by storm events, which induce rapid flow processes by preferential flow bypassing large parts of the soil matrix. However, little is known about the dynamics, magnitude, and driving processes of P exports into surface waters. In this paper, we present the results of a monitoring study in a small forested catchment (21 ha situated in the low mountain ranges of Saxony, Germany. During the fixed schedule-sampling (weekly to bi-weekly sampling frequency for a three-year period, a mean total-P concentration of 8 μg·L−1 was measured. However, concentrations increased up to 203 μg·L−1 during individual storm flow events. Based on the analyzed concentrations and continuously measured discharge we calculated mean annual export rates of 19 to 44 g·ha−1·a−1 for the weekly sampling frequency with different load calculation methods. If events are included into the annual load calculation, the mean annual export fluxes can be up to 83 g·ha−1·a−1 based on the different load calculation methods. Predictions of total-P export rates based on a sampling strategy which does not consider short-term changes due to factors such as storms will substantially underestimate P exports.

  20. Do we need a dynamic snow depth threshold when comparing hydrological models with remote sensing products in mountain catchments?

    Science.gov (United States)

    Engel, Michael; Bertoldi, Giacomo; Notarnicola, Claudia; Comiti, Francesco

    2017-04-01

    threshold of 100 mm, leading to increased OA (> 0.8) in 13‰ of the catchment area. SCA agreement in January 2012 and 2013 was slightly limited by MODIS sensor detection due to shading effects and low illumination in areas exposed north-west to north. On the contrary, during the melting season in April 2013 and after the September 2013 snowfall event seemed to depend more on parameterisation than on snow depth thresholds. In contrast, inaccuracies during the melting season March to June 2013 could hardly be attributed to topographic characteristics and different snow depth thresholds but rather on model parameterisation. We identified specific conditions (p.e. specific snowfall events in autumn 2012 and spring 2013) when either MODIS data or the hydrological model was less accurate, thus justifying the need for improvements of precision in the snow cover detection algorithms or in the model's process description. In consequence, our study observations could support future snow cover evaluations in mountain areas, where spatially and temporally dynamic snow depth thresholds are transferred from the catchment scale to the regional scale. Keywords: snow cover, snow modelling, MODIS, snow depth sensitivity, alpine catchment

  1. Spatial and temporal variation links between nitrate and dissoved organic carbon in a German forested mountainous headwater catchment

    Science.gov (United States)

    Weigand, Susanne; Bydalek, Frank; Bol, Roland; Luecke, Andreas; Tappe, Wolfgang; Reichert, Barbara; Amelung, Wulf; Vereecken, Harry

    2014-05-01

    The spatial and temporal variability of the concentration of dissolved organic carbon (DOC) and nitrate (NO3-) with was studied by means of weekly grab samples over a 4-year period (2009-2013) in a forested headwater catchment (Wuestebach, Germany). Stream water DOC values varied between 0.8-7.4 mg/l, with a mean value 2.7 mg/l, with nitrate ranging 2.8 to 12.2 mg/l, with a mean value of 5.7 mg/l. The DOC values were closely correlated, but negatively to nitrate concentrations (r=-0.56). High DOC in summer and high nitrate were measured in Wuestebach streamwaters. Generally, Surficial water exhibit high DOC, low NO3, high variability and ground waters were characterised by low DOC, high NO3-, and low variability. Within the whole catchment, clear spatial differences in annual trends in DOC and NO3- concentrations in site streams and various superficial components were found. This feature most likely reflected the localized (soil, hydrological and bedrock conditions) difference in the relative contributions of surface and ground water contributions to the streamwater, probably in response to prevailing weather conditions.

  2. Blending Pan-European and local hydrological models for water resource assessment in Mediterranean areas: lessons learnt from a mountainous catchment

    Science.gov (United States)

    José Polo, María; José Pérez-Palazón, María; Saénz de Rodrigáñez, Marta; Pimentel, Rafael; Arheimer, Berit

    2017-04-01

    Global hydrological models provide scientists and technicians with distributed data over medium to large areas from which assessment of water resource planning and use can be easily performed. However, scale conflicts between global models' spatial resolution and the local significant spatial scales in heterogeneous areas usually pose a constraint for the direct use and application of these models' results. The SWICCA (Service for Water Indicators in Climate Change Adaptation) Platform developed under the Copernicus Climate Change Service (C3S) offers a wide range of both climate and hydrological indicators obtained on a global scale with different time and spatial resolutions. Among the different study cases supporting the SWICCA demonstration of local impact assessment, the Sierra Nevada study case (South Spain) is a representative example of mountainous coastal catchments in the Mediterranean region. This work shows the lessons learnt during the study case development to derive local impact indicator tailored to suit the local end-users of water resource in this snow-dominated area. Different approaches were followed to select the most accurate method to downscale the global data and variables to the local level in a highly abrupt topography, in a sequential step approach. 1) SWICCA global climate variable downscaling followed by river flow simulation from a local hydrological model in selected control points in the catchment, together with 2) SWICCA global river flow values downscaling to the control points followed by corrections with local transfer functions were both tested against the available local river flow series of observations during the reference period. This test was performed for the different models and the available spatial resolutions included in the SWICCA platform. From the results, the second option, that is, the use of SWICCA river flow variables, performed the best approximations, once the local transfer functions were applied to the

  3. Selected examples of needs for long term pilot areas in Mediterranean catchments: a mountain traditional agricultural system and a large and regulated hydrographic basin in Southern Spain

    Science.gov (United States)

    José Polo, María; Herrero, Javier; Millares, Agustín; José Pérez-Palazón, María; Pimentel, Rafael; Aguilar, Cristina; Jurado, Alicia; Contreras, Eva; Gómez-Beas, Raquel; Carpintero, Miriam; Gulliver, Zacarías

    2015-04-01

    Integrated River Basin Management (IRBM) aims at planning water, land and other natural resources for an equitable and sustainable management, also capable of preserving or restoring freshwater ecosystems. Long term series of significant variables at different scales and a sound knowledge of the river basin processes are needed to establish the current state and past&future evolution of the hydrological system, soil use and vegetation distribution, and their social impacts and feedbacks. This is particularly crucial if future scenario analyses are to be performed to assess decision-making processes and adaptive plans. This work highlights the need for an adequate design and development of process-oriented monitoring systems at the basin scale in a decision-making framework. First, the hydrologic monitoring network of the Guadalfeo River Basin, in the southern face of Sierra Nevada Range (Spain), is shown, in a pilot catchment of 1300 km2 in which snow processes in Mediterranean conditions have been studied over the last ten years with a holistic approach. The network development and the main features of the dataset are described together with their use for different scientific and environmental applications; their benefits for assessing social and economic impact in the rural environment are shown from a study case in which the sustainability of ancient channels fed by snowmelt, in use since the XIIIth century for traditional irrigated crops in the mountainous area, was assessed in a future scenarios analyses. Secondly, the standard flow and water quality monitoring networks in the Guadalquivir River Basin, a large (57400 km2) and highly regulated agricultural catchment in southern Spain, are shown, and their strengths and weaknessess for an IRBM framework are analysed. Sediments and selected pollutants are used to trace soil erosion and agricultural/urban exports throughout the catchment, and the final loads to the river estuary in the Atlantic Ocean are assessed

  4. Recent advances in understanding climate, glacier and river dynamics in high mountain Asia

    Science.gov (United States)

    Immerzeel, W.

    2016-12-01

    The water cycle in the Himalaya is poorly understood because of its extreme topography that results in complex interactions between climate, water stored in snow and glaciers and the hydrological processes. Hydrological extremes in the greater Himalayas regularly cause great damage, while high mountain Asia also supplies water to over 25% of the global population. So, the stakes are high and an accurate understanding of the Himalayan water cycle is imperative. The hydrology of the greater Himalayas is only marginally resolved due to the intricacy of monsoon dynamics, the poorly quantified dependence on the cryosphere and the physical constraints of doing research in high-altitude and generally inaccessible terrain. However, in recent years significant scientific advances have been made in field monitoring, modelling and remote sensing and the latest progress and outstanding challenges will be presented for three related fields. First focus will be on recent learnings about high altitude climate dynamics and the interaction between the atmosphere and the extreme mountain topography. Secondly, recent advances in how climate controls key glacio-hydrological processes in high-altitude catchments will be discussed with a particular focus on debris covered glaciers. Thirdly, new developments in glacio-hydrological modelling and approaches to climate change impact assessments will be reviewed. Finally, the outstanding scientific challenges will be synthesized that need to be addressed to fully close the high mountain water cycle and to be able to reduce the uncertainty in future projections of water availability and the occurrence of extreme events in high mountain Asia.

  5. Isotopic composition of dissolved inorganic nitrogen in high mountain lakes: variation with altitude in the Pyrenees

    Science.gov (United States)

    Bartrons, M.; Camarero, L.; Catalan, J.

    2010-05-01

    Nitrogen deposition in remote areas has increased, but the effect on ecosystems is still poorly understood. For aquatic systems, knowledge of the main processes driving the observed variation is limited, as is knowledge of how changes in nitrogen supply affect lake biogeochemical and food web processes. Differences in dissolved inorganic nitrogen (DIN) between lakes cannot be understood without considering catchment characteristics. In mountains, catchment features (e.g., thermal conditions, land cover) vary considerably with elevation. The isotopic composition of nitrogen (δ15N) is increasingly used to study aquatic ecosystem dynamics. Here we explore the variability of δ15N in DIN in high mountain lakes and show that environmental conditions that change with altitude can affect the isotopic ratio. We measured ammonium and nitrate δ15N values in atmospheric deposition, epilimnetic water, deep chlorophyll maximum water (DCMW) and sediment pore water (SPW) from eight mountain lakes in the Pyrenees, both above and below the treeline. Lakes showed relatively uniform δ15N-NH4+ values in SPW (2.2±1.6‰), with no variation corresponding to catchment or lake characteristics. We suggest that organic matter diagenesis under similar sediment conditions is responsible for the low variation between the lakes. In the water column, the range of δ15N values was larger for ammonium (-9.4‰ to 7.4‰) than for nitrate (-11.4‰ to -3.4‰), as a result of higher variation both between and within lakes (epilimnetic vs. DCM water). For both compounds part of the difference correlated with altitude or catchment features (e.g., scree proportion). Based on concentration, chemical and isotopic tendencies, we suggest that patterns arise from the distinct relative contributions of two types of water flow paths to the lakes: one from snowpack melting, with little soil interaction; and another highly influenced by soil conditions. The snow-type flow path contributes low DIN

  6. Forest Harvesting of a Rocky Mountain Headwater Catchment: Assessing the Impacts on Runoff and Sediment Transport Into and Through Riparian Buffers

    Science.gov (United States)

    Puntenney, K.; Bladon, K. D.; Silins, U.

    2015-12-01

    Mitigating forest harvesting impacts by retaining a vegetated riparian buffer along headwater streams is a widely implemented best management practice. However, there is still debate over current retention practices and their effectiveness at regulating runoff, erosion, and sediment transport from harvested areas to streams. Forested, headwater catchments on the eastern slopes of the Rocky Mountains (49°37' N, 114°40' W) were harvested in winter 2015. Fixed-width (30 m) riparian buffers were retained based on the regional operating ground rules for all of the identified and mapped hydrologic features. Modified Gerlach troughs (total n=40) were installed along the cutblock-buffer interface, 10 m into the vegetated buffer, and in unharvested control sites to collect runoff and sediment. Site characteristics, including surface soil moisture, slope, vegetation cover, soil type, litter depth, and upslope accumulated area will be used to describe differences in runoff volumes and sediment concentrations between sites. Rainfall simulations are also being used to quantify and compare the initiation of runoff, runoff volumes, and sediment concentrations under high intensity precipitation events in cutblocks, at the cutblock-buffer interface, and within vegetated buffers. Broad objectives of this ongoing study are to identify spatio-temporal hotspots of runoff and sediment transport from cutblocks into and through riparian buffers.

  7. The challenge of lots of data: different ways to synthesise and visualise high frequency catchment data

    Science.gov (United States)

    Jonczyk, Jennine; Barber, Nicholas; Benskin, Claire; Snell, Maria; Deasy, Clare; Reaney, Sim; Quinn, Paul; Owen, Gareth; EdenDTC Team

    2015-04-01

    System understanding is vital for future catchment management and to inform mitigation of both flooding and DWPA. High resolution data sets collected at catchment outlets are becoming more common. They have the potential to provide new insights into how land units process water and how this influences nutrient and ecological dynamics. However, the monitoring equipment is costly to install and operate. Also, the volume of data, both temporally and spatially, presents new challenges to catchment scientists on how best to synthesise these data into a form where they can be visualised and utilised in decision making. The Eden DTC project is part of a national project funded by the UK government to provide robust evidence on how diffuse pollution can be cost-effectively managed to improve and maintain water quality in rural river catchments. The impact of multiple water quality parameters on ecosystems and sustainable food production are being studied at the catchment scale. Three focus catchments (c. 10 km2) have been selected to represent the different farming practices and geophysical characteristics across the Eden catchment, Northern England. A field experimental programme has been designed to monitor the dynamics of agricultural diffuse pollution at multiple scales using state of the art in situ sensors, which provide continuous real-time data. Data generated through this project will be used to explore these challenges and look at different ways to synthesise and visualise these data, ultimately providing a powerful communication mechanism that potentially can be used as a conduit for real holistic catchment management.

  8. Long-term trends and spatial variability in nitrate leaching from alpine catchment-lake ecosystems in the Tatra Mountains (Slovakia-Poland).

    Science.gov (United States)

    Kopácek, Jirí; Stuchlík, Evzen; Wright, Richard F

    2005-07-01

    Relationships between catchment characteristics of 31 alpine lakes and observed trends in lake water concentrations of nitrate were evaluated in the Tatra Mountains. Nitrate concentrations increased from background levels catchment-weighted mean pools (CWM; kgm(-2)) of soil, i.e. with percent land cover with meadow and soil depth, and positively with grade of terrain, annual precipitation, and the highest elevation in the catchment. The CWM pool of soil and annual precipitation explained together 65% of the current spatial variability in nitrate concentrations. Denitrification and direct N deposition on surface area explained 14% of the variability. Increased atmospheric N deposition and declining net N retention in soils were responsible for long-term changes in nitrate concentrations. Long-term decline in %N retention in soils decreased along with the estimated decline in C:N ratios (from 21 to 18 on average during the last 70 years). An empirical model linking nitrate concentrations in different types of alpine Tatra Mountain lakes to four independent variables (CWM soil pool, annual precipitation, increased N deposition, and average trend in soil C:N ratios) explained 80% of the observed spatial and temporal nitrate variability over the period 1937-2000.

  9. Afforestation, subsequent forest fires and provision of hydrological services: a model-based analysis for a Mediterranean mountainous catchment

    Science.gov (United States)

    Nunes, João Pedro; Naranjo Quintanilla, Paula; Santos, Juliana; Serpa, Dalila; Carvalho-Santos, Cláudia; Rocha, João; Keizer, Jan Jacob; Keesstra, Saskia

    2017-04-01

    Mediterranean landscapes have experienced extensive abandonment and reforestation in recent decades, which should have improved the provision of hydrological services, such as flood mitigation, soil erosion protection and water quality regulation. However, these forests are fire-prone, and the post-fire increase in runoff, erosion and sediment exports could negatively affect service provision. This issue was assessed using the SWAT model for a small mountain agroforestry catchment, which was monitored between 2010 and 2014 and where some eucalypt stands burned in 2011 and were subsequently plowed for replanting. The model was calibrated and validated for streamflow, sediment yield and erosion in agricultural fields and the burnt hillslopes, showing that it can be adapted for post-fire simulation. It was then used to perform a decadal assessment of surface runoff, erosion, and sediment exports between 2004 and 2014. Results show that the fire did not noticeably affect flood mitigation but that it increased erosion by 3 orders of magnitude, which subsequently increased sediment yield. Erosion in the burnt forest during this decade was one order of magnitude above that in agricultural fields. SWAT was also used to assess different fire and land-use scenarios during the same period. Results indicate that the impacts of fire were lower without post-fire soil management, and when the fire occurred in pine forests (i.e. before the 1990s) or in shrublands (i.e. before afforestation in the 1930s). These impacts were robust to changes in post-fire weather conditions and to a lower fire frequency (20-year intervals). The results suggest that, in the long term, fire-prone forests might not provide the anticipated soil protection and water quality regulation services in wet Mediterranean regions.

  10. Ecological relations and temporal changes in the pelagial of the high mountain lakes in the Rila Mountains (Bulgaria

    Directory of Open Access Journals (Sweden)

    Teodora TRICHKOVA

    2004-02-01

    Full Text Available The high mountain lakes in the Rila Mountains (Bulgaria were studied in the years 2000 and 2001 considering the following groups of variables: geography, geology, morphology, hydrology, water chemistry of the pelagial, biomass and size structure of bacterio- phyto- and zooplankton, and occurrence of three fish species. Multivariate analysis (RDA revealed that the nutrient concentrations in the lakes were significantly influenced by the soil percentage coverage of the catchment area. The explained variation in plankton components (bacterio-, phyto- and zooplankton and plankton size structure was determined by biological as well as morphometrical and geographical variables. Changes in the Mg2+ and NO3-N concentrations were traced over the period 1993- 2001; the Ca2+ concentration, pH, nutrients, bacterio-, phyto- and zooplankton were monitored in the period 1995-2001. A nutrient decrease accompanied by an increase in size of zooplankton organisms in the period 1995-2001 led to a considerable increase of water transparency in the lakes.

  11. Aspects of seasonality and flood generating circulation patterns in a mountainous catchment in south-eastern Germany

    National Research Council Canada - National Science Library

    Petrow, Th; Merz, B; Lindenschmidt, K.-E; Thieken, A. H

    2007-01-01

    Analyses of discharge series, precipitation fields and flood producing atmospheric circulation patterns reveal that two governing flood regimes exist in the Mulde catchment in south-eastern Germany...

  12. Applications of high resolution rainfall radar data to quantify water temperature dynamics in urban catchments

    Science.gov (United States)

    Croghan, Danny; Van Loon, Anne; Bradley, Chris; Sadler, Jon; Hannnah, David

    2017-04-01

    Studies relating rainfall events to river water quality are frequently hindered by the lack of high resolution rainfall data. Local studies are particularly vulnerable due to the spatial variability of precipitation, whilst studies in urban environments require precipitation data at high spatial and temporal resolutions. The use of point-source data makes identifying causal effects of storms on water quality problematic and can lead to erroneous interpretations. High spatial and temporal resolution rainfall radar data offers great potential to address these issues. Here we use rainfall radar data with a 1km spatial resolution and 5 minute temporal resolution sourced from the UK Met Office Nimrod system to study the effects of storm events on water temperature (WTemp) in Birmingham, UK. 28 WTemp loggers were placed over 3 catchments on a rural-urban land use gradient to identify trends in WTemp during extreme events within urban environments. Using GIS, the catchment associated with each logger was estimated, and 5 min. rainfall totals and intensities were produced for each sub-catchment. Comparisons of rainfall radar data to meteorological stations in the same grid cell revealed the high accuracy of rainfall radar data in our catchments (urban catchment generally received more rainfall, with this effect greatest in the highest intensity storms, suggesting the possibility of urban heat island effects on precipitation dynamics within the catchment. Rainfall radar data provided more accurate sub-catchment rainfall totals allowing better modelled estimates of storm flow, whilst spatial fluctuations in both discharge and WTemp can be simply related to precipitation intensity. Storm flow inputs for each sub-catchment were estimated and linked to changes in WTemp. WTemp showed substantial fluctuations (>1 °C) over short durations (effects of land use and other catchment characteristics in each sub-catchment can be assessed. Our use of the rainfall radar data calls into

  13. Hydrological modeling of fecal indicator bacteria in a tropical mountain catchment

    Science.gov (United States)

    The occurrence of pathogen bacteria in surface waters is a threat to public health worldwide. In particular, inadequate sanitation resulting in high contamination of surface water with pathogens of fecal origin is a serious issue in developing countries such as Lao P.D.R. Despite the health implicat...

  14. Impacts of Spatial Climatic Representation on Hydrological Model Calibration and Prediction Uncertainty: A Mountainous Catchment of Three Gorges Reservoir Region, China

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-02-01

    Full Text Available Sparse climatic observations represent a major challenge for hydrological modeling of mountain catchments with implications for decision-making in water resources management. Employing elevation bands in the Soil and Water Assessment Tool-Sequential Uncertainty Fitting (SWAT2012-SUFI2 model enabled representation of precipitation and temperature variation with altitude in the Daning river catchment (Three Gorges Reservoir Region, China where meteorological inputs are limited in spatial extent and are derived from observations from relatively low lying locations. Inclusion of elevation bands produced better model performance for 1987–1993 with the Nash–Sutcliffe efficiency (NSE increasing by at least 0.11 prior to calibration. During calibration prediction uncertainty was greatly reduced. With similar R-factors from the earlier calibration iterations, a further 11% of observations were included within the 95% prediction uncertainty (95PPU compared to the model without elevation bands. For behavioral simulations defined in SWAT calibration using a NSE threshold of 0.3, an additional 3.9% of observations were within the 95PPU while the uncertainty reduced by 7.6% in the model with elevation bands. The calibrated model with elevation bands reproduced observed river discharges with the performance in the calibration period changing to “very good” from “poor” without elevation bands. The output uncertainty of calibrated model with elevation bands was satisfactory, having 85% of flow observations included within the 95PPU. These results clearly demonstrate the requirement to account for orographic effects on precipitation and temperature in hydrological models of mountainous catchments.

  15. Impacts of precipitation and temperature trends on different time scales on the water cycle and water resource availability in mountainous Mediterranean catchments.

    Science.gov (United States)

    José Pérez-Palazón, María; Pimentel, Rafael; Herrero, Javier; José Polo, María

    2017-04-01

    Climatology trends, precipitation and temperature variations condition the hydrological evolution of the river flow response at basin and sub-basin scales. The link between both climate and flow trends is crucial in mountainous areas, where small variations in temperature can produce significant impacts on precipitation (occurrence as rainfall or snowfall), snowmelt and evaporation, and consequently very different flow signatures. This importance is greater in semiarid regions, where the high variability of the climatic annual and seasonal regimes usually amplifies this impact on river flow. The Sierra Nevada National Park (Southern Spain), with altitudes ranging from 2000 to 3500 m.a.s.l., is part of the global climate change observatories network and a clear example of snow regions in a semiarid environment. This mountain range is head of different catchments, being the Guadalfeo River Basin one of the most influenced by the snow regime. This study shows the observed 55-year (1961-2015) trends of annual precipitation and daily mean temperature, and the associated impacts on snowfall and snow persistence, and the resulting trend of the annual river flow in the Guadalfeo River Basin (Southern Spain), a semiarid abrupt mountainous area (up to 3450 m a.s.l.) facing the Mediterranean Sea where the Alpine and Mediterranean climates coexist in a domain highly influenced by the snow regime, and a significant seasonality in the flow regime. The annual precipitation and annual daily mean temperature experimented a decreasing trend of 2.05 mm/year and an increasing trend of 0.037 °C/year, respectively, during the study period, with a high variability on a decadal basis. However, the torrential precipitation events are more frequent in the last few years of the study period, with an apparently increasing associated dispersion. The estimated annual snowfall trend shows a decreasing trend of 0.24 mm/year, associated to the decrease of precipitation rather than to temperature

  16. A dual stable-isotope approach to analyse the linkages between tree water fluxes and soil water pools in a Mediterranean mountain catchment

    Science.gov (United States)

    Llorens, Pilar; Cayuela, Carles; Sánchez-Costa, Elisenda; Gallart, Francesc; Latron, Jérôme

    2017-04-01

    This work uses a dual isotope-based approach (18O, 2H) to examine the mixing of water in the soil and the linkages between tree water fluxes and soil water pools in a Mediterranean mountain catchment (Vallcebre Research Catchments, NE Spain, 42° 12'N, 1° 49'E). Since May 2015, water-isotopes have been monitored in rainfall, throughfall and stemflow below a Scots pine stand and in stream water at the Can Vila (0.56 km2) catchment outlet. Moreover, fortnightly (From May to December 2015) soil samples (10, 20, 30, 50 and 100 cm), xylem samples (3 Scots pines) and mobile soil water samples in low-suction lysimeters (20, 50 and 100 cm) and in a piezometer (150-300 cm deep) were collected at the same stand. Water from soil and xylem samples was extracted by cryogenic vacuum distillation and isotope analyses were obtained by infrared spectroscopy. All this information has been combined with continuous measurement of meteorological, soil moisture and water potential, piezometric levels and hydrological variables at the stand and catchment scales. Stable isotopes ratios of bound soil water fell below the local meteoric water line (LMWL), with more evaporative enrichment in the shallow horizons. On the contrary, mobile soil water (low suction lysimeters) and groundwater fell along the LMWL, well mixed with stream water. The differences observed between these two water pools remained similar during the whole study period. Stable isotopes ratios indicate that Scots pine trees use shallow bound soil water during the whole study period. No marked changes in depth of water uptake were observed, presumably due to the availability of water in the shallow horizons, even during the summer months.

  17. How High Can A Mountain Be ?

    Indian Academy of Sciences (India)

    tribpo

    tain is limited by a weak stratum in gently sloping sedimentary rock—a case not uncommon on earth. However, the simple argument below shows that it is not a sufficient condition in the simplest case of a mountain made of a homogeneous rock. Consider a long hill, i.e. a ridge, of uniform cross section as shown in Fig.

  18. Modeling the terrestrial N processes in a small mountain catchment through INCA-N: A case study in Taiwan.

    Science.gov (United States)

    Lu, Meng-Chang; Chang, Chung-Te; Lin, Teng-Chiu; Wang, Lih-Jih; Wang, Chiao-Ping; Hsu, Ting-Chang; Huang, Jr-Chuan

    2017-09-01

    Riverine dissolved inorganic nitrogen (DIN) is an important indicator of trophic status of aquatic ecosystems. High riverine DIN export in Taiwan, ~3800kg-Nkm-2yr-1, which is ~18 times higher than the global average, urges the need of thorough understanding of N cycling processes. We applied INCA-N (Integrated Nitrogen Catchment Model) to simulate riverine DIN export and infer terrestrial N processes using weekly rainwater and streamwater samples collected at the Fushan Experimental Forest (FEF) of northern Taiwan. Results showed that the modeled discharge and nitrate export are in good agreement with observations, suggesting the validity of our application. Based on our modeling, the three main N removal processes, in the order of descending importance, were plant uptake, riverine N transport and denitrification at FEF. The high plant uptake rate, 4920kg-Nkm-2yr-1, should have led to accumulation of large biomass but biomass at FEF was relatively small compared to other tropical forests, likely due to periodic typhoon disruptions. The low nitrate concentration but high DIN export highlights the importance of hydrological control over DIN export, particularly during typhoons. The denitrification rate, 750kg-Nkm-2yr-1, at FEF was also low compared to other tropical forest ecosystems, likely resulting from quick water drainage through the coarse-loamy top soils. The high DIN export to atmospheric deposition ratio, 0.45, suggests that FEF may be in advanced stages of N excess. This simulation provides useful insights for establishing monitoring programs and improves our understanding N cycling in subtropical watersheds. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

    Science.gov (United States)

    Campbell, J. M.; Jordan, P.; Arnscheidt, J.

    2014-09-01

    This study reports the use of high resolution water quality monitoring to assess the influence of changes in landuse management on total phosphorus (TP) transfers in two 5 km2 agricultural sub-catchments. Specifically, the work investigates the "wicked problem" of agricultural soil P management and subsequent diffuse transfers at high river flows over a five year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STS) and mitigation efforts - here termed the "filthy issue" of rural catchment management. Results showed an inconsistent response to soil P management over five years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STS) and also to gauge their effectiveness.

  20. Autogenic versus allogenic controls on the evolution of a coupled fluvial megafan-mountainous catchment system: numerical modelling and comparison with the Lannemezan megafan system (northern Pyrenees, France)

    Science.gov (United States)

    Mouchené, Margaux; van der Beek, Peter; Carretier, Sébastien; Mouthereau, Frédéric

    2017-02-01

    Alluvial megafans are sensitive recorders of landscape evolution, controlled by both autogenic processes and allogenic forcing, and they are influenced by the coupled dynamics of the fan with its mountainous catchment. The Lannemezan megafan in the northern Pyrenean foreland was abandoned by its mountainous feeder stream during the Quaternary and subsequently incised, leaving a flight of alluvial terraces along the stream network. We use numerical models to explore the relative roles of autogenic processes and external forcing in the building, abandonment and incision of a foreland megafan, and we compare the results with the inferred evolution of the Lannemezan megafan. Autogenic processes are sufficient to explain the building of a megafan and the long-term entrenchment of its feeding river on time and space scales that match the Lannemezan setting. Climate, through temporal variations in precipitation rate, may have played a role in the episodic pattern of incision on a shorter timescale. In contrast, base-level changes, tectonic activity in the mountain range or tilting of the foreland through flexural isostatic rebound do not appear to have played a role in the abandonment of the megafan.

  1. Mountains

    Science.gov (United States)

    Regina M. Rochefort; Laurie L. Kurth; Tara W. Carolin; Robert R. Mierendorf; Kimberly Frappier; David L. Steenson

    2006-01-01

    This chapter concentrates on subalpine parklands and alpine meadows of southern British Columbia, Washington, Oregon, and western Montana. These areas lie on the flanks of several mountain ranges including the Olympics, the Cascades of Oregon and Washington, and the Coast Mountains in British Columbia.

  2. Microbial Cell Budget of a High-Arctic Supraglacial Catchment

    Science.gov (United States)

    Irvine-Fynn, T. D.; Edwards, A.; Newton, S.; Langford, H.; Rassner, S. M.; Telling, J.; Anesio, A. M.; Hodson, A. J.

    2012-12-01

    There is a growing recognition of glaciers as ecosystems and a source of organic matter delivered to downstream environments. Recently, researchers have focussed on examination of interred cells entombed within the glacier body and the dissolved organic matter, particularly carbon, conveyed in meltwaters. However, due to a reliance on cell concentration measurements derived from ice cores rather than meltwater runoff, uncertainty surrounds the estimates of contributions in the form of microbial cells' particulate carbon liberated from glaciers. Here, using flow cytometry, we present the first enumeration of biological particles draining from a supraglacial catchment on Midtre Lovénbreen (Svalbard) over a 36-day study period. An average in-stream cell flux of 1.08×107 cells m-2 hr-1 was found. Non-linear associations between water discharge and biological particle concentrations were identified, which provides insight into glacier surface hydraulics. Crucially, contrast between ice-melt and aeolian inputs to, and the fluvial output from the monitored catchment suggested storage of 8.83×107 cells m-2 hr-1. The physical retention of particulates at glacier surfaces may contribute to mass thinning through the feedbacks altering surface ice albedo. Nonetheless, over the period of observation, 7.5×1014 cells were conveyed from the glacier, and allometric relationships between cells and nutrients allowed estimates of the corresponding carbon, protein and DNA delivery to downstream environments. This study demonstrates that interactions between biological processes and ice surface hydraulics merit further investigation not only for nutrient release, but also for better comprehension of mechanisms behind global ice mass wastage and the primary colonisation of newly exposed glacier forefields.raph illustrating discharge (Q) vs. supraglacial in-stream cell flux

  3. River recharge sources and the partitioning of catchment evapotranspiration fluxes as revealed by stable isotope signals in a typical high-elevation arid catchment

    Science.gov (United States)

    Guo, Xiaoyu; Tian, Lide; Wang, Lei; Yu, Wusheng; Qu, Dongmei

    2017-06-01

    Catchment-scale hydrological cycles are expected to suffer more extremes under a background of climate change. Quantifying hydrological changes in high and remote areas is practically challenging. However, stable isotopes in river water can be seen to vary, dependent upon the combined influence exerted by recharge sources and local climatic conditions; the study of river water stable isotopes can therefore provide a meaningful method for delineating catchment-scale hydrological studies. In this study, we present high-resolution time series of river δ18O and d-excess values; additionally, we identify the seasonal dynamics of river recharge sources and major components of the catchment-scale water balance, together with precipitation and groundwater isotopes, and concurrent meteorological data recorded in Magazangbu catchment on the northwestern Tibetan Plateau (TP). Using isotopic analysis, and within a proportional framework, we partitioned the isotopic fractionation (E1) or non-fractionation (E2) from soil evaporation fluxes (Esoil) apparent in different processes, using NDVI (Normal Differential Vegetation Index) data collected by MODIS satellites to calculate the vegetation fractional coverage (VFC), and Global Land Data Assimilation System (GLDAS) records to determine evapotranspiration data (ET). Finally, the contributions made by each ET component (Esoil and plant transpiration) to total catchment ET were computed for the high and remote northwestern TP. Our results show that: (1) river δ18O values were high in summer and low in winter, while d-excess values displayed a contrary seasonal cycle; (2) for the monsoon period, precipitation contributed 60.6% to Magazangbu catchment runoff. Deeper groundwater was the main water source for the winter low base flow, and shallow groundwater or high elevation snowmelt was the principal component of the spring thaw and autumn freezing periods; and (3) a substantial proportion of Esoil (96.4% annually; 92.2% during

  4. The effect of spatial soil variation on the hydrology of a semi-arid Rocky Mountains catchment

    NARCIS (Netherlands)

    Diek, S.; Temme, A.J.A.M.; Teuling, A.J.

    2014-01-01

    Soil properties can exhibit strong spatial variability, even at the small catchment scale. However, the hydrological implications of actual variability remain widely unknown since the required data are not easily collected. This is especially true for observations of covariation between local soil

  5. Model-based analysis of the influence of catchment properties on hydrologic partitioning across five mountain headwater subcatchments.

    Science.gov (United States)

    Kelleher, Christa; Wagener, Thorsten; McGlynn, Brian

    2015-06-01

    Ungauged headwater basins are an abundant part of the river network, but dominant influences on headwater hydrologic response remain difficult to predict. To address this gap, we investigated the ability of a physically based watershed model (the Distributed Hydrology-Soil-Vegetation Model) to represent controls on metrics of hydrologic partitioning across five adjacent headwater subcatchments. The five study subcatchments, located in Tenderfoot Creek Experimental Forest in central Montana, have similar climate but variable topography and vegetation distribution. This facilitated a comparative hydrology approach to interpret how parameters that influence partitioning, detected via global sensitivity analysis, differ across catchments. Model parameters were constrained a priori using existing regional information and expert knowledge. Influential parameters were compared to perceptions of catchment functioning and its variability across subcatchments. Despite between-catchment differences in topography and vegetation, hydrologic partitioning across all metrics and all subcatchments was sensitive to a similar subset of snow, vegetation, and soil parameters. Results also highlighted one subcatchment with low certainty in parameter sensitivity, indicating that the model poorly represented some complexities in this subcatchment likely because an important process is missing or poorly characterized in the mechanistic model. For use in other basins, this method can assess parameter sensitivities as a function of the specific ungauged system to which it is applied. Overall, this approach can be employed to identify dominant modeled controls on catchment response and their agreement with system understanding.

  6. Model‐based analysis of the influence of catchment properties on hydrologic partitioning across five mountain headwater subcatchments

    Science.gov (United States)

    Wagener, Thorsten; McGlynn, Brian

    2015-01-01

    Abstract Ungauged headwater basins are an abundant part of the river network, but dominant influences on headwater hydrologic response remain difficult to predict. To address this gap, we investigated the ability of a physically based watershed model (the Distributed Hydrology‐Soil‐Vegetation Model) to represent controls on metrics of hydrologic partitioning across five adjacent headwater subcatchments. The five study subcatchments, located in Tenderfoot Creek Experimental Forest in central Montana, have similar climate but variable topography and vegetation distribution. This facilitated a comparative hydrology approach to interpret how parameters that influence partitioning, detected via global sensitivity analysis, differ across catchments. Model parameters were constrained a priori using existing regional information and expert knowledge. Influential parameters were compared to perceptions of catchment functioning and its variability across subcatchments. Despite between‐catchment differences in topography and vegetation, hydrologic partitioning across all metrics and all subcatchments was sensitive to a similar subset of snow, vegetation, and soil parameters. Results also highlighted one subcatchment with low certainty in parameter sensitivity, indicating that the model poorly represented some complexities in this subcatchment likely because an important process is missing or poorly characterized in the mechanistic model. For use in other basins, this method can assess parameter sensitivities as a function of the specific ungauged system to which it is applied. Overall, this approach can be employed to identify dominant modeled controls on catchment response and their agreement with system understanding. PMID:27642197

  7. Community perception of water quality in a mining-affected area: a case study for the Certej catchment in the Apuseni Mountains in Romania.

    Science.gov (United States)

    Dogaru, Diana; Zobrist, Jürg; Balteanu, Dan; Popescu, Claudia; Sima, Mihaela; Amini, Manouchehr; Yang, Hong

    2009-06-01

    Mining-contaminated sites and the affected communities at risk are important issues on the agenda of both researchers and policy makers, particularly in the former communist block countries in Eastern Europe. Integrated analyses and expert based assessments concerning mining affected areas are important in providing solid policy guidelines for environmental and social risk management and mitigation. Based on a survey for 103 households conducted in a former mining site in the Certej Catchment of the Apuseni Mountains, western Romania, this study assesses local communities' perceptions on the quality of water in their living area. Logistic regression was used to examine peoples' perception on the quality of the main river water and of the drinking water based on several predictors relating to social and economic conditions. The results from the perception analysis were then compared with the measurements of heavy metal contamination of the main river and drinking water undertaken in the same study area. The findings indicate that perception and measurement results for the water quality in the Certej Catchment are convergent, suggesting an obvious risk that mining activities pose on the surface water. However, the perception on drinking water quality was little predicted by the regression model and does not seem to be so much related to mining as to other explanatory factors, such as special mineralogy of rock and soils or improper water treatment infrastructure, facts suggested by the measurements of the contaminants. Discussion about the implications of these joint findings for risk mitigation policies completes this article.

  8. Community Perception of Water Quality in a Mining-Affected Area: A Case Study for the Certej Catchment in the Apuseni Mountains in Romania

    Science.gov (United States)

    Dogaru, Diana; Zobrist, Jürg; Balteanu, Dan; Popescu, Claudia; Sima, Mihaela; Amini, Manouchehr; Yang, Hong

    2009-06-01

    Mining-contaminated sites and the affected communities at risk are important issues on the agenda of both researchers and policy makers, particularly in the former communist block countries in Eastern Europe. Integrated analyses and expert based assessments concerning mining affected areas are important in providing solid policy guidelines for environmental and social risk management and mitigation. Based on a survey for 103 households conducted in a former mining site in the Certej Catchment of the Apuseni Mountains, western Romania, this study assesses local communities’ perceptions on the quality of water in their living area. Logistic regression was used to examine peoples’ perception on the quality of the main river water and of the drinking water based on several predictors relating to social and economic conditions. The results from the perception analysis were then compared with the measurements of heavy metal contamination of the main river and drinking water undertaken in the same study area. The findings indicate that perception and measurement results for the water quality in the Certej Catchment are convergent, suggesting an obvious risk that mining activities pose on the surface water. However, the perception on drinking water quality was little predicted by the regression model and does not seem to be so much related to mining as to other explanatory factors, such as special mineralogy of rock and soils or improper water treatment infrastructure, facts suggested by the measurements of the contaminants. Discussion about the implications of these joint findings for risk mitigation policies completes this article.

  9. Isotopic composition of dissolved inorganic nitrogen in high mountain lakes: variation with altitude in the Pyrenees

    Directory of Open Access Journals (Sweden)

    M. Bartrons

    2010-05-01

    Full Text Available Nitrogen deposition in remote areas has increased, but the effect on ecosystems is still poorly understood. For aquatic systems, knowledge of the main processes driving the observed variation is limited, as is knowledge of how changes in nitrogen supply affect lake biogeochemical and food web processes. Differences in dissolved inorganic nitrogen (DIN between lakes cannot be understood without considering catchment characteristics. In mountains, catchment features (e.g., thermal conditions, land cover vary considerably with elevation. The isotopic composition of nitrogen (δ15N is increasingly used to study aquatic ecosystem dynamics. Here we explore the variability of δ15N in DIN in high mountain lakes and show that environmental conditions that change with altitude can affect the isotopic ratio.

    We measured ammonium and nitrate δ15N values in atmospheric deposition, epilimnetic water, deep chlorophyll maximum water (DCMW and sediment pore water (SPW from eight mountain lakes in the Pyrenees, both above and below the treeline. Lakes showed relatively uniform δ15N-NH4+ values in SPW (2.2±1.6‰, with no variation corresponding to catchment or lake characteristics. We suggest that organic matter diagenesis under similar sediment conditions is responsible for the low variation between the lakes.

    In the water column, the range of δ15N values was larger for ammonium (−9.4‰ to 7.4‰ than for nitrate (−11.4‰ to −3.4‰, as a result of higher variation both between and within lakes (epilimnetic vs. DCM water. For both compounds part of the difference correlated with altitude or catchment features (e.g., scree proportion. Based on concentration, chemical and isotopic tendencies, we suggest that patterns arise from the distinct relative contributions of two types of water flow paths to the lakes: one from snowpack melting, with little soil

  10. Spatiotemporal Trends in the Timing and Volume of Snowfall in High Mountain Asia

    Science.gov (United States)

    Smith, Taylor; Bookhagen, Bodo

    2017-04-01

    High Mountain Asia, which encompasses the Himalaya, Karakoram, Pamir, Tien Shan, and the Tibetan Plateau, is the primary 'water tower' for much of Asia, serving more than a billion downstream users. Many catchments receive the majority of their yearly water budget in the form of snow - the vast majority of which is not monitored by sparse weather networks in the region. We leverage passive microwave data, flown on five sensors (SSMI, AMSR-E, SSMIS, AMSR2, and GPM, 1987-2016), to examine trends in the timing, volume, and spatial distribution of snowfall. While the total volume of water stored in snowpack has decreased over the study period, this large-scale water-storage loss hides small-scale and seasonal complexities. Some regions, such as the high Tien Shan and Kunlun Shan, have seen increased snow-water storage. Other regions, such as the Pamir and Karakorum, have seen increases in winter snow-water storage, coupled with decreases in summer snow-water storage, implying an intensification of winter storms alongside more rapid spring and summer snowmelt. We also note a non-linear elevation trend, where the mid-elevation zones show the largest negative snow-water storage trends, implying that these areas are the most strongly impacted by increasing temperatures in the region. Our study provides a first-order examination of snow-water trends in High Mountain Asia, and highlights that both small and large-scale snow trends must be considered for effective water planning.

  11. Improving Environmental Projections in the High Mountains of Northern Eurasia

    Science.gov (United States)

    Groisman, Pavel; Aizen, Vladimir

    2009-12-01

    International Workshop on the Northern Eurasia High Mountain Ecosystems; Bishkek, Kyrgyzstan, 9-13 September 2009; The northern Eurasia high mountains, particularly in dry regions of Central Asia, are critically important because they are the source of the water supply for the densely populated lowlands. These regions are highly vulnerable to climatic and environmental changes. Global warming, current and future expected retreat of seasonal snow cover and glaciers, and changes in precipitation pattern and type significantly affect river runoff, permafrost, and groundwater. Moreover, the majority of mountain regions in northern Eurasia are characterized by growing anthropogenic pressure that causes harmful feedback, including desertification of lowlands; wind erosion; contamination of the atmosphere, surface waters, and groundwaters; reduction in crop yield; and increasing human mortality rates.

  12. High-resolution monitoring of catchment nutrient response to the end of the 2011-2012 drought in England, captured by the demonstration test catchments

    Science.gov (United States)

    Outram, F. N.; Lloyd, C.; Jonczyk, J.; Benskin, C. McW. H.; Grant, F.; Dorling, S. R.; Steele, C. J.; Collins, A. L.; Freer, J.; Haygarth, P. M.; Hiscock, K. M.; Johnes, P. J.; Lovett, A. L.

    2013-12-01

    The Demonstration Test Catchments (DTC) project is a UK Government funded initiative to test the effectiveness of on-farm mitigation measures designed to reduce agricultural pollution without compromising farm productivity. Three distinct catchments in England have been chosen to test the efficacy of mitigation measures on working farms in small tributary sub-catchments equipped with continuous water quality monitoring stations. The Hampshire Avon in the south is a mixed livestock and arable farming catchment, the River Wensum in the east is a lowland catchment with predominantly arable farming and land use in the River Eden catchment in the north-west is predominantly livestock farming. One of the many strengths of the DTC as a national research platform is that it provides the ability to investigate catchment hydrology and biogeochemical response across different landscapes and geoclimatic characteristics, with a range of differing flow behaviours, geochemistries and nutrient chemistries. Although numerous authors present studies of individual catchment responses to storms, no studies exist of multiple catchment responses to the same rainfall event captured with in situ high-resolution nutrient monitoring at a national scale. This paper brings together findings from all three DTC research groups to compare the response of the catchments to a major storm event in April 2012. This was one of the first weather fronts to track across the country following a prolonged drought period affecting much of the UK through 2011-2012, marking an unusual meteorological transition when a rapid shift from drought to flood risk occurred. The effects of the weather front on discharge and water chemistry parameters, including nitrogen species (NO3-N and NH4-N) and phosphorus fractions (total P (TP) and total reactive P (TRP)), measured at a half-hourly time step are examined. When considered in the context of one hydrological year, flow and concentration duration curves reveal that

  13. Using global Climate Impact Indicators to assess water resource availability in a Mediterranean mountain catchment: the Sierra Nevada study case (Spain) in the SWICCA platform

    Science.gov (United States)

    José Pérez-Palazón, María; Pimentel, Rafael; Sáenz de Rodrigáñez, Marta; Gulliver, Zacarias; José Polo, María

    2017-04-01

    Climate services provide water resource managements and users with science-based information on the likely impacts associated to the future climate scenarios. Mountainous areas are especially vulnerable to climate variations due to the expected changes in the snow regime, among others; in Mediterranean regions, this shift involves significant effects on the river flow regime and water resource availability and management. The Guadalfeo River Basin is a 1345 km2 mountainous, coastal catchment in southern Spain, ranging from the Mediterranean Sea coastline to the Sierra Nevada mountains to the north (up to 3450 m a.s.l.) within a 40-km distance. The climate variability adds complexity to this abrupt topography and heterogeneous area. The uncertainty associated to snow occurrence and persistence for the next decades poses a challenge for the current and future water resource uses in the area. The development of easy-to-use local climate indicators and derived decision-making variables is key to assess and face the economic impact of the potential changes. The SWICCA (Service for Water Indicators in Climate Change Adaptation) Platform (http://swicca.climate.copernicus.eu/) has been developed under the Copernicus Climate Change Service (C3S) and provides global climate and hydrology indicators on a Pan-European scale. Different case studies are included to assess the platform development and contents, and analyse the indicators' performance from a proof-of-concept approach that includes end-users feedbacks. The Guadalfeo River Basin is one of these case studies. This work presents the work developed so far to analyse and use the SWICCA Climate Impact Indicators (CIIs) related to river flow in this mountainous area, and the first set of local indicators specifically designed to assess selected end-users on the potential impact associated to different climate scenarios. Different CIIs were extracted from the SWICCA interface and tested against the local information

  14. MODIS snow cover mapping accuracy in a small mountain catchment – comparison between open and forest sites

    Directory of Open Access Journals (Sweden)

    G. Blöschl

    2012-07-01

    Full Text Available Numerous global and regional validation studies have examined MODIS snow mapping accuracy by using measurements at climate stations, which are mainly at open sites. MODIS accuracy in alpine and forested regions is, however, still not well understood. The main objective of this study is to evaluate MODIS (MOD10A1 and MYD10A1 snow cover products in a small experimental catchment by using extensive snow course measurements at open and forest sites. The MODIS accuracy is tested in the Jalovecky creek catchment (northern Slovakia in the period 2000–2011. The results show that the combined Terra and Aqua images enable snow mapping at an overall accuracy of 91.5%. The accuracies at forested, open and mixed land uses at the Červenec sites are 92.7%, 98.3% and 81.8%, respectively. The use of a 2-day temporal filter enables a significant reduction in the number of days with cloud coverage and an increase in overall snow mapping accuracy. In total, the 2-day temporal filter decreases the number of cloudy days from 61% to 26% and increases the snow mapping accuracy to 94%. The results indicate three possible factors leading to misclassification of snow as land: patchy snow cover, limited MODIS geolocation accuracy and mapping algorithm errors. Out of a total of 27 misclassification cases, patchy snow cover, geolocation issues and mapping errors occur in 12, 12 and 3 cases, respectively.

  15. Pathophysiology of acute mountain sickness and high altitude pulmonary oedema

    DEFF Research Database (Denmark)

    Sutton, J R; Lassen, N

    1979-01-01

    We review the evidence that acute mountain sickness (AMS) and high altitude pulmonary oedema (HAPO) occur together more often than is realized. We hypothesize that AMS and HAPO have a common pathophysiological basis: both are due to increased pressure and flow in the microcirculation, causing...

  16. Mammals of the Kammanassie Mountains, southern Cape Province ...

    African Journals Online (AJOL)

    The mammal fauna of the Kammanassie Mountain State Forest Reserve and Mountain Catchment Area was censused in the high-rainfall southeastern sector and low-rainfall northwestern sector from 2 -12 February, 1979. Collecting yielded 287 specimens of 17 species of small mammals, while the presence of a further 16 ...

  17. Using stable water isotopes and borehole NMR to inform an ecohydrological model in a subalpine and upper montane catchment in the Rocky Mountains

    Science.gov (United States)

    Millar, D.; Parsekian, A.; Mercer, J.; Speckman, H. N.; Beverly, D.; Ewers, B. E.; Mackay, D. S.

    2016-12-01

    Recent work using stable water isotopes has revealed that vegetation across a range of different biomes preferentially take up tightly bound soil water over more mobile pools. This so called two water worlds hypothesis (TWWH) has important implications for hydrological modeling efforts in ecosystems where it holds true, since few if any ecohydrological models incorporate this phenomenon. Further, in ecosystems where the TWWH is supported, information regarding the proportion of soil water in the bound and mobile pools is necessary to inform plant-soil water dynamics in models. In this study, we investigate which soil water pools are used by dominant vegetation in an upper montane and subalpine catchment in the Rocky Mountains of southern Wyoming, and use this information to inform the Terrestrial Regional Ecosystem Exchange Simulator (TREES). Within each catchment, we test the TWWH using stable water isotope analyses in an upland coniferous forest and an adjacent, downgradient groundwater-supported wetland. The proportion of soil water in each pool within each ecosystem was inferred from borehole nuclear magnetic resonance (NMR). These field data are being incorporated into TREES, by partitioning plant water uptake between bound and mobile pools. NMR analyses were conducted in all four ecosystems down to a depth of approximately 75 cm and revealed that while mid growing season soil water content was approximately two-fold higher in the subalpine forest versus that of the upper montane forest, the vast majority of soil water, 86% on average, existed in the bound pool in both ecosystems. Alternatively, soils in both wetlands were saturated throughout their profiles, with a majority of the soil water existing in the mobile pool, 63% on average. These initial findings highlight the importance of bound soil water pools in both upland forests, as opposed to the wetlands, which had an abundance of water in both pools.

  18. Hydrology in a mediterranean mountain environment. The Vallcebre research catchment (north eastern Spain) III. Vegetation and water fluxes; Hidrologia de un ambiente Mediterraneo de montana. Las cuencas de Vallcebre (pirineo oriental) III. Vegetacion y flujos de agua

    Energy Technology Data Exchange (ETDEWEB)

    Llorens, P.; Poyatos, R.; Muzylo, A.; Rubio, C. M.; Latron, J.; Delgado, J.; Gallart, F.

    2009-07-01

    The Vallcebre research catchment are located in a Mediterranean mountain area (Pyrenean, range, NE Spain). These catchments were originally covered by Quercus pubescens Willd. and deforested for agricultural use in the past. Nowadays they are covered by mesophyle grasses with spontaneous afforestation by Pinus sylvestris L. In this context, different investigations studying water fluxes in the soil-vegetation-atmosphere continuum have been performed. the main objective of these studies is the analysis and modelling of the role of vegetation cover on the catchment water balance in a framework of climate and land use changes. The dynamics of rainfall interception and transpiration by Scots pines and pubescens oaks, are investigated in terms of their dependence on meteorological conditions, on soil moisture and water table depth. (Author) 13 refs.

  19. Trapping of Organochlorine Compounds in High Mountain Lakes

    Directory of Open Access Journals (Sweden)

    Joan O. Grimalt

    2001-01-01

    Full Text Available High mountain areas have recently been observed to be polluted by organochlorine compounds (OC despite their isolation. These persistent pollutants arrive at these remote regions through atmospheric transport. However, the mechanisms involving the accumulation of these compounds from the atmospheric pool to the lacustrine systems still need to be elucidated. These mechanisms must be related to the processes involving the transfer of these pollutant from low to high latitudes[1] as described in the global distillation effect[2].

  20. Improved understanding and prediction of the hydrologic response of highly urbanized catchments through development of the Illinois Urban Hydrologic Model

    Science.gov (United States)

    Cantone, Joshua; Schmidt, Arthur

    2011-08-01

    What happens to the rain in highly urbanized catchments? That is the question that urban hydrologists must ask themselves when trying to integrate the hydrologic and hydraulic processes that affect the hydrologic response of urban catchments. The Illinois Urban Hydrologic Model (IUHM) has been developed to help answer this question and improve understanding and prediction of hydrologic response in highly urbanized catchments. Urban catchments are significantly different than natural watersheds, but there are similarities that allow features of the pioneering geomorphologic instantaneous unit hydrograph concept developed for natural watersheds to be adapted to the urban setting. This probabilistically based approach is a marked departure from the traditional deterministic models used to design and simulate urban sewer systems and does not have the burdensome input data requirements that detailed deterministic models possess. Application of IUHM to the CDS-51 catchment located in the village of Dolton, Illinois, highlights the model's ability to predict the hydrologic response of the catchment as well as the widely accepted SWMM model and is in accordance with observed data recorded by the United States Geological Survey. In addition, the unique structure and organization of urban sewer networks make it possible to characterize a set of ratios for urban catchments that allow IUHM to be applied when detailed input data are not available.

  1. Sylvicultural procedures in catchment areas of the mountain streams as exemplified by the Skrzyczne massif in Poland

    Directory of Open Access Journals (Sweden)

    Małek Stanisław

    2014-03-01

    Full Text Available Extensive disintegration of spruce forests in the Beskidy Mts. in South Poland generates a need to regenerate sizeable areas as well as to rebuild forest stands which have defended themselves against breakdown. In practice, the magnitude of relevant management tasks does not allow for keeping up with the progressive destruction of forest, especially at higher altitudes, where natural regeneration does not occur as much as necessary. In addition, the species composition is limited to spruce, sometimes accompanied by beech and fir, whereas other species have a negligible share. What may be helpful in solving this problem is the method of regeneration of such areas and of establishment of under-canopy cultures, consisting of patchwork, multi-stage regeneration task performance, starting from the areas with the best chance of reforestation success and using the existing self-sown trees. Such areas undoubtedly include habitats with better water balance, i.e. humid habitats (in the case of larger areas, distinguished in the forest management plan as humid forest site types. The aim of the present study was to propose management of watercourses and headwater areas in the region of the Skrzyczne massif where the selected catchments are situated on the southern (the Malinowski Stream and the northern (the Roztoka Czyrna stream slopes of this massif. The research was carried out in August 2012 and included juxtaposition of available hydrological maps with actual field conditions along with identification of springs and streams and the course of their beds in order to update the existing data. The updating of the forest numerical maps in the existing databases of the State Forests IT System (SILP included verification of the course of streams and determination of their nature (permanent or periodic with a division into the existing ones and the added ones. The data was recorded against the background of the division of the forest surface, contour lines

  2. Hydrology and landscape structure control subalpine catchment carbon export

    Science.gov (United States)

    Vincent Jerald Pacific

    2009-01-01

    Carbon export from high elevation ecosystems is a critical component of the global carbon cycle. Ecosystems in northern latitudes have become the focus of much research due to their potential as large sinks of carbon in the atmosphere. However, there exists limited understanding of the controls of carbon export from complex mountain catchments due to strong spatial and...

  3. Differences in stream flow in relation to changes in land cover: a comparative study in two sub-Mediterranean mountain catchments.

    NARCIS (Netherlands)

    Lana-Renault, N.; Latron, J.; Karssenberg, D.J.; Serrano-Muela, P.; Regüés, D.; Bierkens, M.F.P.

    2011-01-01

    The stream flow response of two neighboring catchments in the central Spanish Pyrenees was compared for 26 rainstorms covering both catchments: one catchment (2.84 km2) was extensively used for agriculture in the past, and the other (0.92 km2) is covered by dense natural forest. Their similarity in

  4. Using wind fields from a high resolution atmospheric model for simulating snow dynamics in mountainous terrain

    OpenAIRE

    Bernhardt, Matthias

    2008-01-01

    It is widely known that the snow cover has a major influence on the hydrology of Alpine watersheds. Snow acts as temporal storage for precipitation during the winter season. The stored water is later released as snowmelt and represents an important component of water supply for the downstream population of large mountain-foreland river systems worldwide. Modelling the amount and position of the snow water stored in the headwater catchments helps to quantify the available water resources and t...

  5. What can we learn from fluvial incision in high mountains?

    Science.gov (United States)

    Fuchs, Margret; Gloaguen, Richard; Krbetschek, Matthias

    2013-04-01

    High and actively deforming mountain ranges attract the attention of geoscientists as they provide natural laboratories of fast evolving process-response systems. Tectonic compressional settings, often linked to perpendicular extension, control the topographic growth and hence, erosion, transport pathways and sedimentation. High altitude differences within short horizontal distances promote material re-organisation and high rates of surface processes. Furthermore, high mountains constitute orographic barriers that affect atmospheric circulations as well as host different climate regimes similar to those of widely separated latitudinal belts. Both cause a high sensitivity of surface processes to changes in climatic conditions. However, feedbacks between climatic and tectonic forcing are complex. Additionally, the dominance of one or the other varies in space and also over time, inheriting various traces of the paleo-morphodynamic conditions to the subsequent process regimes. To unravel the forces driving the evolution of relief in active mountains, numerous studies employ the drainage network of the corresponding mountains as a proxy of landscape evolution. Especially the rates of river incision provide a powerful tool to characterize the surface response and infer causes behind it. Several parameters of river incision are available to describe the fluvial incision at individual sites (e.g. terrace incision rates), along the river course (e.g. longitudinal river profiles, Hack index) and in its perpendicular dimension (e.g. valley cross sections, valley shape ratios). But they require careful interpretation. They are sensitive to both, climatic and tectonic forcing. Therefore, the synopsis of such indices for fluvial incision is essential to evaluate the role of climatic versus tectonic forcing. Here, we use the Panj river system, the major river draining the Pamir mountains of Central Asia, as an example. The Panj experiences high altitude changes of more than 4000

  6. Future high-mountain hydrology: a new parameterization of glacier retreat

    Directory of Open Access Journals (Sweden)

    M. Huss

    2010-05-01

    Full Text Available Global warming is expected to significantly affect the runoff regime of mountainous catchments. Simple methods for calculating future glacier change in hydrological models are required in order to reliably assess economic impacts of changes in the water cycle over the next decades. Models for temporal and spatial glacier evolution need to describe the climate forcing acting on the glacier, and ice flow dynamics. Flow models, however, demand considerable computational resources and field data input and are moreover not applicable on the regional scale. Here, we propose a simple parameterization for calculating the change in glacier surface elevation and area, which is mass conserving and suited for hydrological modelling. The Δh-parameterization is an empirical glacier-specific function derived from observations in the past that can easily be applied to large samples of glaciers. We compare the Δh-parameterization to results of a 3-D finite-element ice flow model. As case studies, the evolution of two Alpine glaciers of different size over the period 2008–2100 is investigated using regional climate scenarios. The parameterization closely reproduces the distributed ice thickness change, as well as glacier area and length predicted by the ice flow model. This indicates that for the purpose of transient runoff forecasts, future glacier geometry change can be approximated using a simple parameterization instead of complex ice flow modelling. Furthermore, we analyse alpine glacier response to 21st century climate change and consequent shifts in the runoff regime of a highly glacierized catchment using the proposed methods.

  7. Improving catchment scale water quality modelling with continuous high resolution monitoring of metals in runoff

    Science.gov (United States)

    Saari, Markus; Rossi, Pekka; Blomberg von der Geest, Kalle; Mäkinen, Ari; Postila, Heini; Marttila, Hannu

    2017-04-01

    High metal concentrations in natural waters is one of the key environmental and health problems globally. Continuous in-situ analysis of metals from runoff water is technically challenging but essential for the better understanding of processes which lead to pollutant transport. Currently, typical analytical methods for monitoring elements in liquids are off-line laboratory methods such as ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) and ICP-MS (ICP combined with a mass spectrometer). Disadvantage of the both techniques is time consuming sample collection, preparation, and off-line analysis at laboratory conditions. Thus use of these techniques lack possibility for real-time monitoring of element transport. We combined a novel high resolution on-line metal concentration monitoring with catchment scale physical hydrological modelling in Mustijoki river in Southern Finland in order to study dynamics of processes and form a predictive warning system for leaching of metals. A novel on-line measurement technique based on micro plasma emission spectroscopy (MPES) is tested for on-line detection of selected elements (e.g. Na, Mg, Al, K, Ca, Fe, Ni, Cu, Cd and Pb) in runoff waters. The preliminary results indicate that MPES can sufficiently detect and monitor metal concentrations from river water. Water and Soil Assessment Tool (SWAT) catchment scale model was further calibrated with high resolution metal concentration data. We show that by combining high resolution monitoring and catchment scale physical based modelling, further process studies and creation of early warning systems, for example to optimization of drinking water uptake from rivers, can be achieved.

  8. High diversity of protistan plankton communities in remote high mountain lakes in the European Alps and the Himalayan mountains.

    Science.gov (United States)

    Kammerlander, Barbara; Breiner, Hans-Werner; Filker, Sabine; Sommaruga, Ruben; Sonntag, Bettina; Stoeck, Thorsten

    2015-04-01

    We analyzed the genetic diversity (V4 region of the 18S rRNA) of planktonic microbial eukaryotes in four high mountain lakes including two remote biogeographic regions (the Himalayan mountains and the European Alps) and distinct habitat types (clear and glacier-fed turbid lakes). The recorded high genetic diversity in these lakes was far beyond of what is described from high mountain lake plankton. In total, we detected representatives from 66 families with the main taxon groups being Alveolata (55.0% OTUs 97%, operational taxonomic units), Stramenopiles (34.0% OTUs 97%), Cryptophyta (4.0% OTUs 97%), Chloroplastida (3.6% OTUs 97%) and Fungi (1.7% OTUs 97%). Centrohelida, Choanomonada, Rhizaria, Katablepharidae and Telonema were represented by <1% OTUs 97%. Himalayan lakes harbored a higher plankton diversity compared to the Alpine lakes (Shannon index). Community structures were significantly different between lake types and biogeographic regions (Fisher exact test, P < 0.01). Network analysis revealed that more families of the Chloroplastida (10 vs 5) and the Stramenopiles (14 vs 8) were found in the Himalayan lakes than in the Alpine lakes and none of the fungal families was shared between them. Biogeographic aspects as well as ecological factors such as water turbidity may structure the microbial eukaryote plankton communities in such remote lakes. © FEMS 2015.

  9. Differences in stream flow in relation to changes in land cover: A comparative study in two sub-Mediterranean mountain catchments

    Science.gov (United States)

    Lana-Renault, N.; Latron, J.; Karssenberg, D.; Serrano-Muela, P.; Regüés, D.; Bierkens, M. F. P.

    2011-12-01

    SummaryThe stream flow response of two neighboring catchments in the central Spanish Pyrenees was compared for 26 rainstorms covering both catchments: one catchment (2.84 km 2) was extensively used for agriculture in the past, and the other (0.92 km 2) is covered by dense natural forest. Their similarity in terms of lithology and topography enabled us to separate the effects of soil and land cover on their hydrological responses. Relative to the forested catchment, peak flows in the past agricultural catchment were always greater (566 vs. 119 l s -1 km -2), the response time was 2- to 3-fold faster (131 vs. 356 min), and the recession limbs were 1-2 orders of magnitude shorter (7 vs. 72 h). Storm flow was usually greater in the former agricultural catchment, especially for low-intermediate sized flood events; only for larger events the storm flow in the forested catchment was sometimes greater. Storm flow differences were closely related to catchment wetness conditions and showed a marked seasonal pattern, with higher values in the past agricultural catchment under dry conditions, and usually higher values in the forested catchment under wet conditions. In the past agricultural catchment, runoff was generated during the entire water year, through both surface (i.e. infiltration excess and saturation excess overland flow) and subsurface flow. We suggest that the forested catchment can be characterized by a dual (or switching) behavior controlled by soil moisture conditions, which regulates the hydrological connectivity and favors the release of large amounts of subsurface flow. Differences in soil depth and permeability, together with differences in vegetation cover, may explain the contrasting dominant runoff generation processes operating in each catchment, and consequently the differences between their hydrograph characteristics.

  10. Post-wildfire landscape change and erosional processes from repeat terrestrial lidar in a steep headwater catchment, Chiricahua Mountains, Arizona, USA

    Science.gov (United States)

    DeLong, Stephen B.; Youberg, Ann M.; DeLong, Whitney M.; Murphy, Brendan P.

    2018-01-01

    Flooding and erosion after wildfires present increasing hazard as climate warms, semi-arid lands become drier, population increases, and the urban interface encroaches farther into wildlands. We quantify post-wildfire erosion in a steep, initially unchannelized, 7.5 ha headwater catchment following the 2011 Horseshoe 2 Fire in the Chiricahua Mountains of southeastern Arizona. Using time-lapse cameras, rain gauges, and repeat surveys by terrestrial laser scanner, we quantify the response of a burned landscape to subsequent precipitation events. Repeat surveys provide detailed pre-and post-rainfall measurements of landscape form associated with a range of weather events. The first post-fire precipitation led to sediment delivery equivalent to 0.017 m of erosion from hillslopes and 0.12 m of erosion from colluvial hollows. Volumetrically, 69% of sediment yield was generated from hillslope erosion and 31% was generated from gully channel establishment in colluvial hollows. Processes on hillslopes included erosion by extensive shallow overland flow, formation of rills and gullies, and generation of sediment-laden flows and possibly debris flows. Subsequent smaller rain events caused ongoing hillslope erosion and local deposition and erosion in gullies. Winter freeze-thaw led to soil expansion, likely related to frost-heaving, causing a net centimeter-scale elevation increase across soil-mantled slopes. By characterizing landscape form, the properties of near-surface materials, and measuring both precipitation and landscape change, we can improve our empirical understanding of landscape response to environmental forcing. This detailed approach to studying landscape response to wildfires may be useful in the improvement of predictive models of flood, debris flow and sedimentation hazards used in post-wildfire response assessments and land management, and may help improve process-based models of landscape evolution.

  11. Post-wildfire landscape change and erosional processes from repeat terrestrial lidar in a steep headwater catchment, Chiricahua Mountains, Arizona, USA

    Science.gov (United States)

    DeLong, Stephen B.; Youberg, Ann M.; DeLong, Whitney M.; Murphy, Brendan P.

    2018-01-01

    Flooding and erosion after wildfires present increasing hazard as climate warms, semi-arid lands become drier, population increases, and the urban interface encroaches farther into wildlands. We quantify post-wildfire erosion in a steep, initially unchannelized, 7.5 ha headwater catchment following the 2011 Horseshoe 2 Fire in the Chiricahua Mountains of southeastern Arizona. Using time-lapse cameras, rain gauges, and repeat surveys by terrestrial laser scanner, we quantify the response of a burned landscape to subsequent precipitation events. Repeat surveys provide detailed pre-and post-rainfall measurements of landscape form associated with a range of weather events. The first post-fire precipitation led to sediment delivery equivalent to 0.017 m of erosion from hillslopes and 0.12 m of erosion from colluvial hollows. Volumetrically, 69% of sediment yield was generated from hillslope erosion and 31% was generated from gully channel establishment in colluvial hollows. Processes on hillslopes included erosion by extensive shallow overland flow, formation of rills and gullies, and generation of sediment-laden flows and possibly debris flows. Subsequent smaller rain events caused ongoing hillslope erosion and local deposition and erosion in gullies. Winter freeze-thaw led to soil expansion, likely related to frost-heaving, causing a net centimeter-scale elevation increase across soil-mantled slopes. By characterizing landscape form, the properties of near-surface materials, and measuring both precipitation and landscape change, we can improve our empirical understanding of landscape response to environmental forcing. This detailed approach to studying landscape response to wildfires may be useful in the improvement of predictive models of flood, debris flow and sedimentation hazards used in post-wildfire response assessments and land management, and may help improve process-based models of landscape evolution.

  12. Glacial landforms and relicts in the high mountains of Taiwan

    Science.gov (United States)

    Chu, H.-T.

    2009-04-01

    Glacial landforms and relicts in the high mountains of Taiwan Hao-tsu Chu Central Geological Survey, MOEA, Taiwan ROC Glacial landforms and relicts are well preserved in the high mountains of Taiwan although substantial orographic precipitation, periglacial, earthquakes, and surface erosion processes have been active ever since the retreat of the last glaciations. Variations of glacial landforms and relicts in the northern, central, and southern areas of Taiwan are attributed mainly to differences in lithology. Cirque glaciers and rectilinear trough valleys are distinctive glacial landforms in the Hseuhshan (3884m) and the Nanhutashan (3742m) area, respectively, in north-central Taiwan. Both of these areas are composed of hard and durable thick layers of meta-sandstone, meta-conglomerate, and quartzite with minor slate. Diagnostic glacial landform and glacial erosional features of streamlined bodies and striated moraines are widely distributed in the high ground above 3300m of the Hohuanshan (3416m) area and the Shangyang Shan (3496m) - Sanchar Shan (3602m) area, respectively in north-central and southern Taiwan. These two areas are mainly composed of weaker rocks of slate, schist with minor meta-sandstones. Whereas in central Taiwan, in the Mount Yushan (3952m) area, limited glacial landforms of polished and striated bedrock surface was found. The preservation of geomorphic surfaces with glacial erosional forms is highly favorable near or at the top of drainage divide where the effect of stream headward erosion, mass wasting, and surface creeping are not obvious.

  13. Drivers for the development of an alluvial fan in a high-altitude glaciated catchment

    Science.gov (United States)

    Steiner, Jakob; Miles, Evan; Ragettli, Silvan

    2016-04-01

    Alluvial fans have channelization and deposition dynamics that are not entirely understood but can have considerable impact on the local hydrological regime. Especially in high-altitude and glaciated catchments they are rather rarely investigated. During glaciological field work between 2012 and 2015 in the Langtang catchment in the Nepalese Himalaya, such an alluvial fan of ca. 0.35 km2 (4000 m a.s.l.) at the end of a very small glaciated subcatchment (~9km2) was observed. The subcatchment is the site of one of the presumed largest landslides in earth's history, that likely happened 40 000 years ago with a volume of approximately 10^10 m3 and land surface erosion is well visible. During the recent Gorkha earthquake in April 2015 (M=7.8), additional sediments were mobilized along the steep valley slopes. From 6 sets of concurrent high-resolution satellite images and DEMs between 2006 and 2015 and an additional image from 1974 we derive the evolution in space and volume of this fan and identify main sources of sediment supply. Precipitation data from a nearby Automatic Weather Station provides insight into strong rainfall events. We can compare the growth of the fan in the period without significant earthquakes until April 2014 to the change after the seismic event (image from May 2015) and after the following Monsoon season (image from October 2015) and determine dominant drivers of erosion.

  14. GEODIVERSITY AUDIT AND ACTION PLAN FOR UPPER CATCHMENT AREA OF GERSA RIVER (RODNEI MOUNTAINS, BISTRIȚA-NĂSĂUD COUNTY, ROMANIA

    Directory of Open Access Journals (Sweden)

    Ioan Bâca

    2015-08-01

    Full Text Available Geodiversity Audit is an inventory and assessment process, wich represents the basis for elaborating the Geoconservation Action Plan. The geodiversity includes the abiotic factors (rocks, minerals, soils, landforms that sustain the life on the Earth, and owns economic, social, environmental, tourist and educational functions. This study proposes an audit of geodiversity from Gersa catcment area and an Action Plan for future planning and tourist valorization projects by local and county authorities. Gersa Valley is a geomorphological subunit located in the southern part of Rodnei Mountains (Bistrița-Năsăud County and contains in the superior sector some landforms with high degree of attractiveness, such as Izvorul Tăușoarelor Cave, Izvorul Calului Gorge and Bârlea Massif. By their configuration these landforms has a great potential for engaging in scientific and recreational activities (caving, hiking, gorge walking, canyoning, mountain biking. Keywords: geodiversity, geologic heritage, geoconservation, geosite, action plan, Rodnei Mountains, Gersa River, Izvorul Tăușoarelor Cave, speotourism, activ leisure

  15. Saltating Snow Mechanics: High Frequency Particle Response to Mountain Wind

    Science.gov (United States)

    Aksamit, N. O.; Pomeroy, J. W.

    2015-12-01

    Blowing snow transport theory is currently limited by its dependency on the coupling of time-averaged measurements of particle saltation and suspension and wind speed. Details of the stochastic process of particle transport and complex bed interactions in the saltation layer, along with the influence of boundary-layer turbulence are unobservable with classic measurement techniques. In contrast, recent advances in two-phase sand transport understanding have been spurred by development of high-frequency wind and particle velocity measurement techniques. To advance the understanding of blowing snow, laser illuminated high-speed videography and ultrasonic anemometry were deployed in a mountain environment to examine saltation of snow over a natural snowpack in detail. A saltating snow measurement site was established at the Fortress Mountain Snow Laboratory, Alberta, Canada and instrumented with two Campbell CSAT3 ultrasonic anemometers, four Campbell SR50 ultrasonic snow depth sounders and a two dimensional Particle Tracking Velocimetry (PTV) system. Measurements were collected during nighttime blowing snow events, quantifying snow particle response to high frequency wind gusts. This novel approach permits PTV to step beyond mean statistics of snow transport by identifying sub-species of saltation motion in the first 20 mm above the surface, as well as previously overlooked initiation processes, such as tumbling aggregate snow crystals ejecting smaller grains, then eventually disintegrating and bouncing into entrainment. Spectral characteristics of snow particle ejection and saltation dynamics were also investigated. These unique observations are starting to inform novel conceptualizations of saltating snow transport mechanisms.

  16. Contribution of snow and glacier melt to discharge for highly glacierised catchments in Norway

    National Research Council Canada - National Science Library

    Engelhardt, M; Schuler, T. V; Andreassen, L. M

    2014-01-01

    .... Calibration and validation were performed for each catchment based on measurements of seasonal glacier mass balances and daily discharge rates, as additional validation data served daily melt rates...

  17. Research in karst aquifers developed in high-mountain areas combining KARSYS models with springs discharge records. Picos de Europa, Spain

    Science.gov (United States)

    Ballesteros, Daniel; Meléndez, Mónica; Malard, Arnauld; Jiménez-Sánchez, Montserrat; Heredia, Nemesio; Jeannin, Pierre-Yves; García-Sansegundo, Joaquín

    2014-05-01

    The study of karst aquifers developed in high-mountain areas is quite complex since the application of many techniques of hydrogeology in these areas is difficult, expensive, and requires many hours of field work. In addition, the access to the study area is usually conditioned by the orography and the meteorological conditions. A pragmatic approach to study these aquifers can be the combination of geometric models of the aquifer with the monitoring of the discharge rate of springs and the meteorological records. KARSYS approach (Jeannin et al. 2013) allows us to elaborate a geometric model of karst aquifers establishing the boundaries of the groundwater bodies, the main drainage axes and providing evidences of the catchment delineation of the springs. The aim of this work is to analyse the functioning of the karst aquifer from the western and central part of the Picos de Europa Mountains (Spain) combining the KARSYS approach, the discharge record from two springs and the meteorological records (rain, snow and temperature). The Picos de Europa (North Spain) is a high-mountains area up to 2.6 km altitude with 2,500 mm/year of precipitations. The highest part of these mountains is covered by snow four to seven months a year. The karst aquifer is developed in Carboniferous limestone which is strongly compartmentalized in, at least, 17 groundwater bodies. The method of work includes: 1) the elaboration of a hydrogeological 3D model of the geometry of the karst aquifers by KARSYS approach, 2) the definition of the springs catchment areas based on the hydrogeological 3D model, 3) the selection of two representative springs emerging from the aquifers to study it, 4) the continuous monitoring of water levels in two karst springs since October 2013, 5) the transformation of the water level values to flow values using height-stream relation curves constructed by measures of the spring discharge, and 5) the comparison of the spring discharge rate records and meteorological

  18. Resprout and Survival of Willow ( Salix) Cuttings on Bioengineering Structures in Actively Eroding Gullies in Marls in a Mountainous Mediterranean Climate: A Large-Scale Experiment in the Francon Catchment (Southern Alps, France)

    Science.gov (United States)

    Rey, F.; Labonne, S.

    2015-10-01

    Improving the understanding of the role of vegetation and bioengineering structures on erosion and sedimentation control, especially in torrent-prone catchments in a mountainous Mediterranean climate, has become a key issue today for the scientific community working in ecological engineering and restoration ecology. The objective of this study was to evaluate the performance of willow ( Salix) cuttings in resprouting and survival on bioengineering structures in actively eroding gullies in marls and to identify the factors influencing this performance. Measurements were taken from 2008 to 2011 on 336 bioengineering structures, namely brush layers on wooden sills (BL) and brush layers with brush mats on wooden sills (BLM), using 8890 cuttings of Salix purpurea and Salix incana. These structures were built in 18 gullies of the Francon Catchment in marls (73 ha) in the Southern French Alps. After four growing seasons, the results revealed a total cutting survival rate of 45 %. They also demonstrated that in BLM, brush mats provided better survival (56 %) than brush layers (37 %). In BL, brush layers alone showed 51 % cutting survival. Cutting resprout and survival were observed for all structure aspects. They were positively related to increasing gully size and vegetation cover on gully sides. The results of this large-scale experiment clarified previous data obtained on a limited sample of bioengineering structures, providing further detail and showing that it is possible to use such structures made of willow cuttings to revegetate actively eroding gullies in marls within a mountainous Mediterranean climate.

  19. Variability in spectral characteristics of trampled high-mountain grasslands

    Directory of Open Access Journals (Sweden)

    Kycko Marlena

    2014-06-01

    Full Text Available The goal of the paper is a presentation of field remote sensing methods for the analysis of the trampled plants of a highly protected mountain meadow ecosystem (M&B UNESCO Reserve and one of the most important Polish National Parks. The research area covers a core part of the Western Tatras - the Gąsienicowa Valley and Kasprowy Wierch summit, which are among the most visited destinations of the Polish Tatras. The research method is based on field hyperspectral measurements, using the ASD FieldSpec 3 spectrometer, on the dominant plant species of alpine swards. Sampling sites were located on trampled areas (next to trails and reference plots, with the same species, but located more than 10 m from the trail (where the probability of trampling was very low, but the same composition of analysed plants. In each case, homogenous plots with a domination of one plant species were investigated. Based on the hyperspectral measurements, spectral characteristics as well as vegetation indices were analysed with the ANOVA statistical test. This indicated a varied resistance to trampling of the studied plant species. The analysis of vegetation indices enabled the selection of those groups which are the most useful for research into mountain vegetation condition: the broadband greenness group; the narrowband greenness group, measuring chlorophyll content and cell structure; and the canopy water content group. The results of the analyses show that vegetation of the High Tatras is characterised by optimal ranges of remote sensing indices. Only plants located nearest to the trails were in a worse condition (chlorophyll and water content was lower for the reference targets. These differences are statistically significant, but the measured values indicate a good condition of vegetation along trampled trails, within the range of optimum plant characteristics.

  20. High bacterial diversity in epilithic biofilms of oligotrophic mountain lakes.

    Science.gov (United States)

    Bartrons, Mireia; Catalan, Jordi; Casamayor, Emilio O

    2012-11-01

    Benthic microbial biofilms attached to rocks (epilithic) are major sites of carbon cycling and can dominate ecosystem primary production in oligotrophic lakes. We studied the bacterial community composition of littoral epilithic biofilms in five connected oligotrophic high mountain lakes located at different altitudes by genetic fingerprinting and clone libraries of the 16S rRNA gene. Different intra-lake samples were analyzed, and consistent changes in community structure (chlorophyll a and organic matter contents, and bacterial community composition) were observed along the altitudinal gradient, particularly related with the location of the lake above or below the treeline. Epilithic biofilm genetic fingerprints were both more diverse among lakes than within lakes and significantly different between montane (below the tree line) and alpine lakes (above the tree line). The genetic richness in the epilithic biofilm was much higher than in the plankton of the same lacustrine area studied in previous works, with significantly idiosyncratic phylogenetic composition (specifically distinct from lake plankton or mountain soils). Data suggest the coexistence of aerobic, anaerobic, phototrophic, and chemotrophic microorganisms in the biofilm, Bacteroidetes and Cyanobacteria being the most important bacterial taxa, followed by Alpha-, Beta-, Gamma-, and Deltaproteobacteria, Chlorobi, Planctomycetes, and Verrucomicrobia. The degree of novelty was especially high for epilithic Bacteroidetes, and up to 50 % of the sequences formed monophyletic clusters distantly related to any previously reported sequence. More than 35 % of the total sequences matched at <95 % identity to any previously reported 16S rRNA gene, indicating that alpine epilithic biofilms are unexplored habitats that contain a substantial degree of novelty within a short geographical distance. Further research is needed to determine whether these communities are involved in more biogeochemical pathways than

  1. High sensitivity of gross primary production in the Rocky Mountains to summer rain

    Science.gov (United States)

    Berkelhammer, M.; Stefanescu, I.C.; Joiner, J.; Anderson, Lesleigh

    2017-01-01

    In the catchments of the Rocky Mountains, peak snowpack is declining in response to warmer spring temperatures. To understand how this will influence terrestrial gross primary production (GPP), we compared precipitation data across the intermountain west with satellite retrievals of solar-induced fluorescence (SIF), a proxy for GPP. Annual precipitation patterns explained most of the spatial and temporal variability of SIF, but the slope of the response was dependent on site to site differences in the proportion of snowpack to summer rain. We separated the response of SIF to different seasonal precipitation amounts and found that SIF was approximately twice as sensitive to variations in summer rain than snowpack. The response of peak GPP to a secular decline in snowpack will likely be subtle, whereas a change in summer rain amount will have precipitous effects on GPP. The study suggests that the rain use efficiency of Rocky Mountain ecosystems is strongly dependent on precipitation form and timing.

  2. Construction of a high resolution precipitation grid over an alpine catchment for multi-scale performance assessment of gridded daily reference data sets.

    Science.gov (United States)

    Gampe, David; Ludwig, Ralf

    2017-04-01

    Precipitation plays a key role in the hydrological cycle and thus is a crucial variable in the meteo-hydrological modeling chain. Accurate spatial and temporal assessment of precipitation is in this context of utmost importance. Gridded reference data sets for precipitation are also needed to evaluate and bias adjust climate model simulations in order to better represent current regional conditions. Uncertainties in these data sets increase when moving to higher spatial resolution, including small-scale processes, and more complex terrain. In this study a high resolution reference data set with a grid size of 1km is derived from over 150 observation stations over the mountainous Adige catchment ( 12,000 km2), located in Northern Italy with elevations up to 3800 m. This gridded product is then applied to evaluate the performance of state-of-the-art reference data sets which are available at various spatial resolutions ranging from several km to climate model scale at 2°. These global or regional data sets stem either directly from observations or re-analysis simulations, with or without assimilated precipitation, or are based remote sensing approaches. The main objective of this study is to address and quantify uncertainties of these coarser data sets. Additionally, whether they perform acceptable on catchment scale and can be applied for bias correction and model calibration, or if regional high resolution data sets outperform these data sets. Comparison is performed at various spatial resolutions corresponding to those of the applied precipitation data sets. Furthermore, an inter comparison of all of these is conducted at a the coarsest common resolution, where higher resolved data sets are aggregated to the target resolution, allowing for an analysis without penalizing data sets at coarse resolution. Performance assessment of the reference data sets is carried out on daily precipitation statistics for the period 1989 - 2008 using a multitude of indicators.

  3. Decadal and seasonal trends of nutrient concentration and export from highly managed coastal catchments.

    Science.gov (United States)

    Wan, Yongshan; Wan, Lei; Li, Yuncong; Doering, Peter

    2017-05-15

    Understanding anthropogenic and hydro-climatic influences on nutrient concentrations and export from highly managed catchments often necessitates trend detection using long-term monitoring data. This study analyzed the temporal trend (1979-2014) of total nitrogen (TN) and total phosphorus (TP) concentrations and export from four adjacent coastal basins in south Florida where land and water resources are highly managed through an intricate canal network. The method of integrated seasonal-trend decomposition using LOESS (LOcally weighted regrESSion) was employed for trend detection. The results indicated that long-term trends in TN and TP concentrations (increasing/decreasing) varied with basins and nutrient species, reflecting the influence of basin specific land and water management practices. These long-term trends were intervened by short-term highs driven by high rainfall and discharges and lows associated with regional droughts. Seasonal variations in TP were more apparent than for TN. Nutrient export exhibited a chemostatic behavior for TN from all the basins, largely due to the biogenic nature of organic N associated with the ubiquity of organic materials in the managed canal network. Varying degrees of chemodynamic export was present for TP, reflecting complex biogeochemical responses to the legacy of long-term fertilization, low soil P holding capacity, and intensive stormwater management. The anthropogenic and hydro-climatic influences on nutrient concentration and export behavior had great implications in nutrient loading abatement strategies for aquatic ecosystem restoration of the downstream receiving waterbody. Published by Elsevier Ltd.

  4. The relative importance of the planktonic food web in the carbon cycle of an oligotrophic mountain lake in a poorly vegetated catchment (Redó, Pyrenees

    Directory of Open Access Journals (Sweden)

    Lluís CAMARERO

    1999-08-01

    Full Text Available The biological activity of the planktonic community of lake Redó, expressed in terms of carbon fluxes, was measured and compared to the changes in DIC, DOC and POC in the water column. Planktonic photosynthesis ranged between c. 0.01 - 0.3 μg C m-2 h-1. Release of EOC phytoplankton was highly variable, between 5 and 80% of total fixation. Bacterial uptake of EOC ranged between 1-20% of total fixation. Bacterial activities were, in absolute numbers, very low: 0.005±0.003 μg C m-2 h-1, in contrast with the higher grazing rates on bacteria of 0.036±0.021 μg C m-2 h-1. Respiration and diffusion of CO2 to the atmosphere seem to be the main processes controlling DIC concentration. DOC and POC concentrations were highly correlated, and their fluxes presented large fluctuations. These changes in DOC are larger than those due to the processes we have measured. Other processes that might affect DOC include diffusion from sediments, inputs from the catchment, uptake by mixotrophic algae and zooplankton, bacterial respiration, UV photoxidation, and flocculation. Lake Redó seems to act in general terms as an heterotrophic system: respiration is higher than photosynthesis, and the budget is balanced by the import of DOC and, to a lesser extent, POC. Most of the carbon seems to be ultimately released to atmosphere, since little is accumulated in sediments. The estimates of diffusive fluxes agreed with this hypothesis. At this stage, the comparison of biogeochemical budgets with biological activity measurements only serves as a rough approximation of the main pathways in the C cycling in the lake, and to point the issues that need further research in order to calculate the C budget in the lake with accuracy.

  5. Impact of climate change on the hydrology of High Mountain Asia

    NARCIS (Netherlands)

    Lutz, A.

    2016-01-01

    In Asia, water resources largely depend on water generated in the mountainous upstream parts of several large river basins and hundreds of millions of people depend on their waters downstream. The large-scale impacts of climate change for the water resources in High Mountain Asia are poorly

  6. High-frequency monitoring of catchment nutrient exports reveals highly variable storm event responses and dynamic source zone activation

    Science.gov (United States)

    Blaen, Phillip J.; Khamis, Kieran; Lloyd, Charlotte; Comer-Warner, Sophie; Ciocca, Francesco; Thomas, Rick M.; MacKenzie, A. Rob; Krause, Stefan

    2017-09-01

    Storm events can drive highly variable behavior in catchment nutrient and water fluxes, yet short-term event dynamics are frequently missed by low-resolution sampling regimes. In addition, nutrient source zone contributions can vary significantly within and between storm events. Our inability to identify and characterize time-dynamic source zone contributions severely hampers the adequate design of land use management practices in order to control nutrient exports from agricultural landscapes. Here we utilize an 8 month high-frequency (hourly) time series of streamflow, nitrate (NO3-N), dissolved organic carbon (DOC), and hydroclimatic variables for a headwater agricultural catchment. We identified 29 distinct storm events across the monitoring period. These events represented 31% of the time series and contributed disproportionately to nutrient loads (42% of NO3-N and 43% of DOC) relative to their duration. Regression analysis identified a small subset of hydroclimatological variables (notably precipitation intensity and antecedent conditions) as key drivers of nutrient dynamics during storm events. Hysteresis analysis of nutrient concentration-discharge relationships highlighted the dynamic activation of discrete NO3-N and DOC source zones, which varied on an event-specific basis. Our results highlight the benefits of high-frequency in situ monitoring for characterizing short-term nutrient fluxes and unraveling connections between hydroclimatological variability and river nutrient export and source zone activation under extreme flow conditions. These new process-based insights, which we summarize in a conceptual model, are fundamental to underpinning targeted management measures to reduce nutrient loading of surface waters.

  7. High Mountain Asia 8-meter DEMs Derived from Along-track Optical Imagery V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains 8-meter Digital Elevation Models (DEMs) of high mountain Asia glacier and snow regions generated from very-high-resolution commercial...

  8. Machine learning and linear regression models to predict catchment-level base cation weathering rates across the southern Appalachian Mountain region, USA

    Science.gov (United States)

    Nicholas A. Povak; Paul F. Hessburg; Todd C. McDonnell; Keith M. Reynolds; Timothy J. Sullivan; R. Brion Salter; Bernard J. Crosby

    2014-01-01

    Accurate estimates of soil mineral weathering are required for regional critical load (CL) modeling to identify ecosystems at risk of the deleterious effects from acidification. Within a correlative modeling framework, we used modeled catchment-level base cation weathering (BCw) as the response variable to identify key environmental correlates and predict a continuous...

  9. Recent high mountain rockfalls and warm daily temperature extremes

    Science.gov (United States)

    Allen, S. K.; Huggel, C.

    2012-04-01

    Linkages between longer term warming of the climate, related changes in the cryosphere, and destabilisation of high mountain rockwalls have been documented in several studies. Although understanding is far from complete, a range of physical processes related to longer term warming are understood to have an effect on slope stability. More recently, some attention has turned to the possible influence of much shorter periods of extremely warm temperatures, as a contributing factor, or even trigger of slope failures. So far, studies have not extended beyond highlighting one or a few individual events, and no common approach to quantifying the 'extremity' of the prevailing temperatures has been used. In the current study, we integrate established practices used in the climatology community in the analyses of climate extremes, together with an inventory of ca. 20 recent rock failures (1987 - 2010) in the central European Alps, to assess temporal relationships between daily air temperature extremes and rock failure occurrence. Using data from three high elevation recording sites across Switzerland, we focus on daily maximum temperatures in the 4 weeks immediately prior to each rockfall occurrence, where an extremely warm day is defined as exceeding the 95th percentile during the climatological reference period of 1971 - 2000. The 95th percentile is calculated in a 21 day moving window, so that extreme temperatures are considered relative to the time of year, and not on an annual basis. In addition, rock failures from the Southern Alps of New Zealand are analysed, although high elevation climate data are limited from this region. Results from the European Alps show that a majority of recent slope failures have been preceded by one or more extreme, unseasonably warm days, most notably in the week immediately prior to the failure. For example, for 9 slope failures in the Valais - Mt Blanc region (based on Grand St Bernhard climate data), 6 were proceeded by extremely warm

  10. Modelling erosion and catchment's sediment exports based on erosion plot's measurements using the STREAM model. Application to the Rheraya catchment, High Atlas, Morocco.

    Science.gov (United States)

    Simonneaux, V.; Deschamps, C.; Cheggour, A.; Le Bissonnais, Y.

    2009-04-01

    Keywords: erosion, modelling, erosion plots, sediment exportation, STREAM The Rheraya watershed (225 km2) is located in a semi-arid climat, in the High Atlas of Morocco. The land cover includes mainly degraded rangelands on the slopes, and some irrigated crops in the valleys. The average annual rainfall ranges between 300 and 500 mm depending on the site location. Six erosion plots of about 150 m2, located on various soil and land cover conditions were measured during four years. The observations showed very rare runoff events in the main part of the watershed, and producing a low sediment load (between 0.015 and 2.5 t/ha/year). Conversely, runoff was much more frequent on silty badlands, producing about 95% of the watershed sediment (350 t/ha/year) despite their area was only 1% of the watershed. The resulting average erosion over the watershed was about 3-4 t/ha/year, which is of the same order than the mean sediment exportation at the outlet, indicating a sediment delivery ratio around 1. STREAM is a semi empirical distributed erosion model initially designed for agricultural landscapes, taking into account as the main drivers of erosion, the vegetation cover, the soil surface states and the soil roughness. These surface characteristics are input by the user for each pixel, allowing the computing of the infiltration capacity and the runoff turbidity. STREAM works for single rain events, and uses a simple hortonian hypothesis for runoff generation for each pixel, which is subsequently routed down slope using a DEM. The adaptation of this model to the very different context of the Rheraya catchment, with mostly rangelands instead of crops, led us to identify three new drivers of soil infiltration and turbidity, namely the soil type, the soil protection by vegetation or stones, and the soil conservation practices. Infiltration and turbidity for each landscape unit were quantified based on the in situ erosion plot measurements. The results of STREAM simulations for

  11. Characterizing Runoff and Water Yield from Headwater Catchments in the Southern Sierra Nevada

    Science.gov (United States)

    Safeeq, M.; Hunsaker, C. T.

    2015-12-01

    In a mediterranean climate where much of the annual precipitation falls during winter, the snow-capped Sierra Nevada serves as the primary source of dry season runoff that supports agriculture, industries, urban, and other ecosystems. Increased warming has led to significant reductions in mountain snowpack accumulation and earlier snowmelt throughout the western United States where most of the snow accumulates at temperatures near the freezing point. As a result, declines in dry season runoff magnitude, earlier runoff timing, and altered flood risk have been reported across the region. An important question in this context is, how to best manage forested catchments for water and other ecosystem services? We depict the differences in hydrologic response of ten catchments in the Kings River Experimental Watersheds (KREW) research project using continuous precipitation, snow, and runoff data during 2004-2014. The size of these catchments ranges from 50 to 475 ha, and they span a 600-m elevation range in the rain snow transitional zone. In terms of soil, Shaver and Gerle-Cagwin dominate the lower elevation Providence catchments, and Cagwin soils dominate the higher elevation Bull catchments. The majority of these catchments have southwest aspect, moderate average slope (i.e. network with drainage density ranging from 4.6 to 10.1 km/km2. Bull catchments, on average, have higher runoff than the Providence catchments across all hydrologic signatures extracted from daily hydrographs. Mean annual runoff ranges between 281 to 408 mm in Providence and 436 to 656 mm in Bull catchments despite no significant difference in precipitation among KREW's four meteorological stations. However, high elevation Bull catchments receive significantly more precipitation as snow than the low elevation Providence catchments. The average runoff ratio ranges from 18% to as high as 43% among different catchments, indicating that the catchment evapotranspiration exceeds the catchment runoff

  12. Soil erosion and sediment delivery in a mountain catchment under land use change: using point fallout 137Cs for calibrating a spatially distributed numerical model

    Science.gov (United States)

    Alatorre, L. C.; Beguería, S.; Lana-Renault, N.; Navas, A.; García-Ruiz, J. M.

    2011-12-01

    Soil erosion and sediment yield are strongly affected by land use/land cover (LULC). Spatially distributed erosion models are useful tools for comparing erosion resulting from current LULC with a number of alternative scenarios, being of great interest to assess the expected effect of LULC changes. In this study the soil erosion and sediment delivery model WATEM/SEDEM was applied to a small experimental catchment in the Central Spanish Pyrenees. Model calibration was carried out based on a dataset of soil redistribution rates derived from 137Cs inventories along three representative transects, allowing capture differences per land use in the main model parameters. Model calibration showed a good convergence to a global optimum in the parameter space. Validation of the model results against seven years of recorded sediment yield at the catchment outlet was satisfactory. Two LULC scenarios where then modeled to reproduce the land use at the beginning of the twentieth Century and a hypothetic future scenario, and to compare the simulation results to the current LULC situation. The results show a reduction of about one order of magnitude in gross erosion (3180 to 350 Mg yr-1) and sediment delivery (11.2 to 1.2 Mg yr-1 ha-1) during the last decades as a result of the abandonment of traditional land uses (mostly agriculture) and subsequent vegetation re-colonization. The simulation also allowed assessing differences in the sediment sources and sinks within the catchment.

  13. Highly pathogenic avian influenza (HPAI) contingency plan for Rocky Mountain Arsenal NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Disease contingency plan to reduce avian mortality from highly pathogenic avian influenza (HAPI) outbreaks at Rocky Mountain Arsenal National Wildlife Refuge. This...

  14. Hydrochemical responses to climate change in high-elevation catchments of the Colorado Front Range. (Invited)

    Science.gov (United States)

    Williams, M. W.

    2009-12-01

    Potential climate impacts on the hydrochemistry of two seasonally snow covered catchments is evaluated using 24 years of data from the Niwot Ridge Long Term Ecological Research Site, Colorado. At the larger (220 ha), higher elevation (3570 m) GL4 catchment annual discharge did not change significantly based on nonparametric trend testing. However, October streaflow volumes and groundwater storage did increase, despite drought conditions near the end of the record in 2000-2004. In contrast, at the smaller (8 ha), lower elevation (3400 m) MART catchment, annual discharge decreased significantly over the study period with the most substantial changes in July-September. The study period was separated into "wet", "normal", and "dry" years based on the 75th and 25th quartiles of annual precipitation. Results indicate that MART is particularly sensitive to changes in precipitation with dry years exhibiting decreased snowmelt peak flows, earlier snowmelt timing, decreased annual discharge, and reduced late-season flows. GL4 was less susceptible to changes in precipitation and surprisingly late-season flow volumes (Sept.-Oct.) were not significantly different between wet, normal, and dry conditions. Surprisingly, during dry years both the concentrations and annual fluxes of Ca2+ and SO42- increased in the outflow of GL4, but not at the Martinelli catchment. These changes in hydrochemistry were particularly pronounced during the low-flow period. Streamwater chemistry in GL4 during drought years resembled that of permafrost, suggesting augmented flow during the fall due to permafrost melt. This study shows that seasonally snow covered catchments are particularly sensitive to changes in climate, but the hydrochemical response may depend on landscape characteristics.

  15. Rainfall–Runoff Simulations to Assess the Potential of SuDS for Mitigating Flooding in Highly Urbanized Catchments

    Directory of Open Access Journals (Sweden)

    Daniel Jato-Espino

    2016-01-01

    Full Text Available Sustainable Urban Drainage Systems (SuDS constitute an alternative to conventional drainage when managing stormwater in cities, reducing the impact of urbanization by decreasing the amount of runoff generated by a rainfall event. This paper shows the potential benefits of installing different types of SuDS in preventing flooding in comparison with the common urban drainage strategies consisting of sewer networks of manholes and pipes. The impact of these systems on urban water was studied using Geographic Information Systems (GIS, which are useful tools when both delineating catchments and parameterizing the elements that define a stormwater drainage system. Taking these GIS-based data as inputs, a series of rainfall–runoff simulations were run in a real catchment located in the city of Donostia (Northern Spain using stormwater computer models, in order to compare the flow rates and depths produced by a design storm before and after installing SuDS. The proposed methodology overcomes the lack of precision found in former GIS-based stormwater approaches when dealing with the modeling of highly urbanized catchments, while the results demonstrated the usefulness of these systems in reducing the volume of water generated after a rainfall event and their ability to prevent localized flooding and surcharges along the sewer network.

  16. A synoptic survey of ecosystem services from headwater catchments in the United States (presentation)

    Science.gov (United States)

    Ecosystem production functions for water supply, climate regulation, and water purification were estimated for 568 headwater streams and their catchments. Water supply per unit catchment area was highest in the Northern Appalachian Mountains and lowest in the Northern Plains. C, ...

  17. A synoptic survey of ecosystem services from headwater catchments in the United States- webinar

    Science.gov (United States)

    Ecosystem production functions for water supply, climate regulation, and water purification were estimated for 568 headwater streams and their catchments. Water supply per unit catchment area was highest in the Northern Appalachian Mountains and lowest in the Northern Plains. C, ...

  18. The shapes of cold, high mountains in sedimentary rocks

    Science.gov (United States)

    Cruden, D. M.

    2003-09-01

    Terzaghi (Geotechnique 12 (1962) 251) and Young (Young, A., 1972. Slopes. Oliver and Boyd, Edinburgh, 288 pp.) described the stable forms of slopes in sedimentary rock masses, assuming penetrative discontinuities, which are parallel to bedding and joints which are perpendicular to bedding. The only movements considered were slides along bedding. Experience in the Canadian Rockies indicates that the cohesionless rock masses that exist at or above tree line may also move by toppling, buckling and sliding along joints. These processes also act to limit the inclinations of stable slopes. Rock strength is a factor in the critical height of a slope that buckles. The processes can be represented as fields on a process diagram, a plot of slope inclination against bedding dip, using the basic friction angles of the rocks present. The process diagram also separates five common mountain peak shapes, which form on homoclinal sequences of beds. Castellate and Matterhorn mountains occur in sub-horizontal beds, cuestas develop in gently to moderately dipping beds. Hogbacks formed in moderately to steeply dipping beds have similar slope angles on both cataclinal and anaclinal slopes. Dogtooth mountains occur in steeply dipping sub-vertical beds.

  19. DETAILED AND HIGHLY ACCURATE 3D MODELS OF HIGH MOUNTAIN AREAS BY THE MACS-HIMALAYA AERIAL CAMERA PLATFORM

    OpenAIRE

    J. Brauchle; D. Hein; R. Berger

    2015-01-01

    Remote sensing in areas with extreme altitude differences is particularly challenging. In high mountain areas specifically, steep slopes result in reduced ground pixel resolution and degraded quality in the DEM. Exceptionally high brightness differences can in part no longer be imaged by the sensors. Nevertheless, detailed information about mountainous regions is highly relevant: time and again glacier lake outburst floods (GLOFs) and debris avalanches claim dozens of victims. Glacie...

  20. Morphological characteristics of overdeepenings in high-mountain glacier beds

    Science.gov (United States)

    Haeberli, Wilfried; Cochachin, Alejo; Fischer, Urs; Giráldez, Claudia; Linsbauer, Andreas; Salazar, Cesar

    2014-05-01

    Overdeepenings, i.e. closed topographic depressions with adverse slopes in the flow direction, are characteristic for glacier beds and glacially sculpted landscapes. Besides their importance as geomorphological landforms, groundwater bodies and sedimentary archives, they are of increasing interest in relation to climate-induced lake formation in de-glaciating landscapes and to depth erosion under ice age conditions in connection with the long-term safety of radioactive waste repositories in some mid-latitude countries. Quantitative predictions of their shape, distribution and conditions of occurrence, however, remain difficult. One major problem thereby relates to the still unsatisfactory treatment in glacier erosion theory of sediment evacuation at glacier beds, especially by subglacial meltwater. An alternative way of searching for realistic/empirical quantitative estimates is, therefore, to analyse the geometry of well-documented overdeepenings. The present study attempts to do this by combining statistical analyses of (a) detailed bathymetries from recently exposed lakes in the Peruvian Andes, (b) numerous bed overdeepenigs below still existing glaciers of the Swiss Alps and the Himalaya-Karakoram region modelled with a robust shear stress approximation linking surface slope to ice thickness at high resolution, and (c, for comparison) reconstructed overdeepenings produced by ice age glaciers in the Swiss Plateau based on numerous drillings and geophysical soundings. The sample of (a) has the advantage that geometries are exactly measured and only subject to young/small sedimentation effects. Sample (b) allows for a comparison with a modern model calculation and with known glacier characteristics. Sample (c) may provide some insights into the question how safely results from high mountain topography can be transferred to sites with markedly different topographic, climatic and glaciological controls (cold-arid lowland). Where possible, mean and maximum values of

  1. Mountains, Climate Change and North American Water Security

    Science.gov (United States)

    Pomeroy, J. W.; Fang, X.; Whitfield, P. H.; Rasouli, K.; Harder, P.; Siemens, E.; Pradhananga, D.

    2016-12-01

    The juxtaposition of cold high precipitation catchments in mountains and low precipitation in downstream lowlands means that mountain water supplies support over half the world's population and sustain most irrigation agriculture. How secure is this mountain water in northern North America? Irrigation and other consumptive downstream uses have put immense pressure on water supplied from the Canadian Rockies. Excess water from these rivers also carries risk. Downstream communities are often located in the flood plains of mountain rivers, making them subject to the extreme hydrometeorology of the headwaters as was evident in the BC/Alberta/Saskatchewan floods of 2013 and droughts of 2015/2016. Climate change is disproportionately warming high mountain areas and the impacts of warming on water are magnified in high mountains because seasonal snowpacks, perennial snowfields and glaciers form important stores of water and control the timing of release of water and the seasonal and annual discharge of major mountain rivers. Changes in mountain snow and glacial regimes are rapidly occurring in Western Canada and this is already impacting downstream water security by changing flood risk, streamflow timing and volume. Hydrological process modelling is diagnosing the causes of intensification of hydrological cycling and coupled to climate models suggesting that the timing and quantity of mountain waters will shift under certain climate, glacier cover and forest cover scenarios and so impact the water security of downstream food production. So far, changes in precipitation are matched by evapotranspiration and sublimation providing some resilience to change in streamflow due to intensification of hydrological cycling. Faster glacier melt in drought periods has buffered low flows but this capacity id dwindling as glaciers ablate. The International Network for Alpine Research Catchment Hydrology (INARCH) project of GEWEX is quantifying water resiliency and risk in mountain

  2. Soil erosion and sediment delivery in a mountain catchment under scenarios of land use change using a spatially distributed numerical model

    Directory of Open Access Journals (Sweden)

    L. C. Alatorre

    2012-05-01

    Full Text Available Soil erosion and sediment yield are strongly affected by land use/land cover (LULC. Spatially distributed erosion models are of great interest to assess the expected effect of LULC changes on soil erosion and sediment yield. However, they can only be applied if spatially distributed data is available for their calibration. In this study the soil erosion and sediment delivery model WATEM/SEDEM was applied to a small (2.84 km2 experimental catchment in the Central Spanish Pyrenees. Model calibration was performed based on a dataset of soil redistribution rates derived from point 137Cs inventories, allowing capture differences per land use in the main model parameters. Model calibration showed a good convergence to a global optimum in the parameter space, which was not possible to attain if only external (not spatially distributed sediment yield data were available. Validation of the model results against seven years of recorded sediment yield at the catchment outlet was satisfactory. Two LULC scenarios were then modeled to reproduce land use at the beginning of the twentieth century and a hypothetic future scenario, and to compare the simulation results to the current LULC situation. The results show a reduction of about one order of magnitude in gross erosion (3180 to 350 Mg yr−1 and sediment delivery (11.2 to 1.2 Mg yr−1 ha−1 during the last decades as a result of the abandonment of traditional land uses (mostly agriculture and subsequent vegetation recolonization. The simulation also allowed assessing differences in the sediment sources and sinks within the catchment.

  3. Soil erosion and sediment delivery in a mountain catchment under scenarios of land use change using a spatially distributed numerical model

    Science.gov (United States)

    Alatorre, L. C.; Beguería, S.; Lana-Renault, N.; Navas, A.; García-Ruiz, J. M.

    2012-05-01

    Soil erosion and sediment yield are strongly affected by land use/land cover (LULC). Spatially distributed erosion models are of great interest to assess the expected effect of LULC changes on soil erosion and sediment yield. However, they can only be applied if spatially distributed data is available for their calibration. In this study the soil erosion and sediment delivery model WATEM/SEDEM was applied to a small (2.84 km2) experimental catchment in the Central Spanish Pyrenees. Model calibration was performed based on a dataset of soil redistribution rates derived from point 137Cs inventories, allowing capture differences per land use in the main model parameters. Model calibration showed a good convergence to a global optimum in the parameter space, which was not possible to attain if only external (not spatially distributed) sediment yield data were available. Validation of the model results against seven years of recorded sediment yield at the catchment outlet was satisfactory. Two LULC scenarios were then modeled to reproduce land use at the beginning of the twentieth century and a hypothetic future scenario, and to compare the simulation results to the current LULC situation. The results show a reduction of about one order of magnitude in gross erosion (3180 to 350 Mg yr-1) and sediment delivery (11.2 to 1.2 Mg yr-1 ha-1) during the last decades as a result of the abandonment of traditional land uses (mostly agriculture) and subsequent vegetation recolonization. The simulation also allowed assessing differences in the sediment sources and sinks within the catchment.

  4. Spatiotemporal variability in stream chemistry in a high-elevation catchment affected by mine drainage

    Science.gov (United States)

    Sullivan, Annett B.; Drever, James I.

    2001-10-01

    This study examined solute dynamics on both spatial and temporal (seasonal, 24 h) scales in a high-elevation stream affected by drainage from abandoned metal mines. Peru Creek is located along the Continental Divide in the US Rocky Mountains, and the hydrologic cycle is dominated by melting of snow. Spatially, tributary inflows produced order-of-magnitude concentration changes along Peru Creek; these were due to dilution and concentration, and also to precipitation of solids. Seasonally, the concentration of most solutes increased as snowmelt diminished. Concentrations of Al, Fe, Cu and Zn, at times affected by instream processes, increased the most, by factors of 2.1-12.8. Ca, Mg, and SO 42-, which approximated conservative behavior, increased by factors of 1.7-2.2. Si, Na and K, which were unaffected by mine drainage, increased less, by factors of 1.1-1.6. Concentrations of NO 3- decreased slightly during the snowmelt season. Hydrologic, photochemical and biological processes were active on the 24 h timescale and produced daily concentration variations of up to 40%. Accurate predictions of solute concentrations, which rely on knowledge of processes that produce natural cycling, are crucial in developing models of toxicity and pollutant loading.

  5. Using high resolution water quality monitoring across three English catchments to capture a storm event during a transition from dry to wet conditions

    Science.gov (United States)

    Outram, F.; Lloyd, C.; Jonczyk, J.; Benskin, C.; Grant, F.

    2013-12-01

    from high resolution data are used to highlight an array of pollutant sources and delivery pathways. Phosphorus delivery to the stream was source-limited in the River Wensum but transport-limited in the Avon and Eden rivers. Load calculations show that nitrogen losses were an order of magnitude higher per hectare in the Wensum catchment than in the Avon catchment. These data demonstrate the consequences during such times of transition and the importance of understanding the relationship between water quality and meteorological conditions, with each catchment highlighting pressures from different pollutants.

  6. Optic Nerve Sheath Diameter Increase on Ascent to High Altitude: Correlation With Acute Mountain Sickness.

    Science.gov (United States)

    Kanaan, Nicholas C; Lipman, Grant S; Constance, Benjamin B; Holck, Peter S; Preuss, James F; Williams, Sarah R

    2015-09-01

    Elevated optic nerve sheath diameter on sonography is known to correlate with increased intracranial pressure and is observed in acute mountain sickness. This study aimed to determine whether optic nerve sheath diameter changes on ascent to high altitude are associated with acute mountain sickness incidence. Eighty-six healthy adults enrolled at 1240 m (4100 ft), drove to 3545 m (11,700 ft) and then hiked to and slept at 3810 m (12,500 ft). Lake Louise Questionnaire scores and optic nerve sheath diameter measurements were taken before, the evening of, and the morning after ascent. The incidence of acute mountain sickness was 55.8%, with a mean Lake Louise Questionnaire score ± SD of 3.81 ± 2.5. The mean maximum optic nerve sheath diameter increased on ascent from 5.58 ± 0.79 to 6.13 ± 0.73 mm, a difference of 0.91 ± 0.55 mm (P = .09). Optic nerve sheath diameter increased at high altitude regardless of acute mountain sickness diagnosis; however, compared to baseline values, we observed a significant increase in diameter only in those with a diagnosis of acute mountain sickness (0.57 ± 0.77 versus 0.21 ± 0.76 mm; P = .04). This change from baseline, or Δ optic nerve sheath diameter, was associated with twice the odds of developing acute mountain sickness (95% confidence interval, 1.08-3.93). The mean optic nerve sheath diameter increased on ascent to high altitude compared to baseline values, but not to a statistically significant degree. The magnitude of the observed Δ optic nerve sheath diameter was positively associated with acute mountain sickness diagnosis. No such significant association was found between acute mountain sickness and diameter elevation above standard cutoff values, limiting the utility of sonography as a diagnostic tool. © 2015 by the American Institute of Ultrasound in Medicine.

  7. Flow modelling in a high mountain valley equipped with hydropower plants: Rio Zongo Valley, Cordillera Real, Bolivia

    Science.gov (United States)

    Caballero, Yvan; Chevallier, Pierre; Gallaire, Robert; Pillco, Ramiro

    2004-04-01

    Water management modelling of a hydroelectric system in a tropical high mountain context is presented. The study zone and the hydraulic network are described and the water management strategy analysed. Three different models are combined to describe the complexity of the specific hydrometeorological context: the spatial distribution of the climatic data over the river basin, the surface energy balance influence on the runoff production of a river basin and the surface flow transfer modelling through a hydraulic system. The atmospheric forcing spatial distribution is derived from the available climatic data records. The runoff production on the catchment's slopes is simulated using the land-surface scheme ISBA. The system dynamics tool Vensim® is used to simulate the hydraulic dynamics in the hydropower plants system. A short description of the three modelling methods is given, followed by the description of the coupled model construction. The simulation results of the ISBA land-surface scheme on both a non-glacial an a glacial sub-basin during a 17 month period are presented. After pointing out the necessity of the water management model to simulate the river discharge at the outlet of the basin, the main reservoirs, simulated water level variations are shown.

  8. Why do tropical mountains support exceptionally high biodiversity? The Eastern Arc mountains and the drivers of Saintpaulia diversity.

    Directory of Open Access Journals (Sweden)

    Dimitar Dimitrov

    Full Text Available We combine information about the evolutionary history and distributional patterns of the genus Saintpaulia H. Wendl. (Gesneriaceae; 'African violets' to elucidate the factors and processes behind the accumulation of species in tropical montane areas of high biodiversity concentration. We find that high levels of biodiversity in the Eastern Arc Mountains are the result of pre-Quaternary speciation processes and environmental stability. Our results support the hypothesis that climatically stable mountaintops may have acted as climatic refugia for lowland lineages during the Pleistocene by preventing extinctions. In addition, we found evidence for the existence of lowland micro-refugia during the Pleistocene, which may explain the high species diversity of East African coastal forests. We discuss the conservation implications of the results in the context of future climate change.

  9. Why do tropical mountains support exceptionally high biodiversity? The Eastern Arc mountains and the drivers of Saintpaulia diversity.

    Science.gov (United States)

    Dimitrov, Dimitar; Nogués-Bravo, David; Scharff, Nikolaj

    2012-01-01

    We combine information about the evolutionary history and distributional patterns of the genus Saintpaulia H. Wendl. (Gesneriaceae; 'African violets') to elucidate the factors and processes behind the accumulation of species in tropical montane areas of high biodiversity concentration. We find that high levels of biodiversity in the Eastern Arc Mountains are the result of pre-Quaternary speciation processes and environmental stability. Our results support the hypothesis that climatically stable mountaintops may have acted as climatic refugia for lowland lineages during the Pleistocene by preventing extinctions. In addition, we found evidence for the existence of lowland micro-refugia during the Pleistocene, which may explain the high species diversity of East African coastal forests. We discuss the conservation implications of the results in the context of future climate change.

  10. Evaluation of the SAFRAN-ISBA-RAPID hydrometeorological chain on a mountainous catchment in a semi-arid region. Case of the Rheraya (Marrakech, Morocco)

    Science.gov (United States)

    Szczypta, Camille; Gascoin, Simon; Habets, Florence; Saaidi, Amina; Berjamy, Brahim; Marchane, Ahmed; Boulet, Gilles; Hanich, Lahoucine; Jarlan, Lionel

    2015-04-01

    The water content of snow pack is an important resource for many watershed in semi-arid areas where downstream plains are dominated by irrigated agriculture. As part of the ANR Amethyst, this work is to develop, adapt and evaluate a hydro-meteorological forecasting chain for quantifying streamflows at the outlet of a mountainous watershed (Rheraya wadi, Marrakech region, Morocco), a pilot basin instrumented since 2003 as part of SudMed project. Two sets of atmospheric forcing were used: (1) The first was generated by spatializing meteorological data observed on 6 stations (Asni, Aremdt, Tachedert, Oukaimeden, Imskerbour and Neltner) using the semi-physical module Micromet (Liston and Elder, 2006) on the hydrological period September 2003 - August 2012; (2) the second is provided by the SAFRAN re-analysis, implemented by the Metoffice of Morocco (Casablanca, Morocco), during the period August 2004 - July 2008. These two sets were then used as inputs for the ISBA surface model, within the modeling platform SURFEX. Finally, runoff and drainage simulations derived from ISBA were forced into the hydrological model RAPID to predict streamflows. The flows predictions and the snow covered area (SCA) were compared respectively to the observations available for the 2003-2009 period and to the daily MODIS products of SCA. Despite time unsystematic lags and low biases on flow values, the initial results are encouraging due to topographical and hydro-complexity of the studied area. Despite a slight tendency to underestimate the SCA for the "Micromet" run and to over-estimate for the "Safran" run, SCA is well reproduced with a determination coefficient of r²=0.76 and r²=0.79, respectively. Given the complex topography of the basin, a sensitivity analysis to the size of the grid point (from 8 km to 250 m) was conducted. If the different simulated series of SCA are close from a resolution to another, streamflows simulations are, by contrast, highly sensitive to the resolution

  11. Impacts of Forest Fires and Climate Variability on the Hydrology of an Alpine Medium Sized Catchment in the Canadian Rocky Mountains

    OpenAIRE

    Springer, Johanna; Ludwig, Ralf; Kienzle, Stefan

    2015-01-01

    This study investigates the hydrology of Castle River in the southern Canadian Rocky Mountains. Temperature and precipitation data are analyzed regarding a climate trend between 1960 and 2010 and a general warming is identified. Observed streamflow has been declining in reaction to a decreasing snow cover and increasing evapotranspiration. To simulate the hydrological processes in the watershed, the physically based hydrological model WaSiM (Water Balance Simulation Model) is applied. Calibra...

  12. Understanding and improving mitigation strategies for reducing catchment scale nutrient loads using high resolution observations and uncertainty analysis approaches

    Science.gov (United States)

    Collins, A.; Lloyd, C.; Freer, J. E.; Johnes, P.; Stirling, M.

    2012-12-01

    One of the biggest challenges in catchment water quality management is tackling the problem of reducing water pollution from agriculture whilst ensuring food security nationally. Improvements to catchment management plans are needed if we are to enhance biodiversity and maintain good ecological status in freshwater ecosystems, while producing enough food to support a growing global population. In order to plan for a more sustainable and secure future, research needs to quantify the uncertainties and understand the complexities in the source-mobilisation-delivery-impact continuum of pollution and nutrients at all scales. In the UK the Demonstration Test Catchment (DTC) project has been set up to improve water quality specifically from diffuse pollution from agriculture by enhanced high resolution monitoring and targeted mitigation experiments. The DTC project aims to detect shifts in the baseline trend of the most ecologically-significant pollutants resulting from targeted on-farm measures at field to farm scales and assessing their effects on ecosystem function. The DTC programme involves three catchments across the UK that are indicative of three different typologies and land uses. This paper will focus on the Hampshire Avon DTC, where a total of 12 parameters are monitored by bank-side stations at two sampling sites, including flow, turbidity, phosphate and nitrate concentrations at 30 min resolution. This monitoring is supported by daily resolution sampling at 5 other sites and storm sampling at all locations. Part of the DTC project aims to understand how observations of water quality within river systems at different temporal resolutions and types of monitoring strategies enable us to understand and detect changes over and above the natural variability. Baseline monitoring is currently underway and early results show that high-resolution data is essential at this sub-catchment scale to understand important process dynamics. This is critical if we are to design

  13. Wind constraints on the thermoregulation of high mountain lizards.

    Science.gov (United States)

    Ortega, Zaida; Mencía, Abraham; Pérez-Mellado, Valentín

    2017-03-01

    Thermal biology of lizards affects their overall physiological performance. Thus, it is crucial to study how abiotic constraints influence thermoregulation. We studied the effect of wind speed on thermoregulation in an endangered mountain lizard (Iberolacerta aurelioi). We compared two populations of lizards: one living in a sheltered rocky area and the other living in a mountain ridge, exposed to strong winds. The preferred temperature range of I. aurelioi, which reflects thermal physiology, was similar in both areas, and it was typical of a cold specialist. Although the thermal physiology of lizards and the structure of the habitat were similar, the higher wind speed in the exposed population was correlated with a significant decrease in the effectiveness thermoregulation, dropping from 0.83 to 0.74. Our results suggest that wind reduces body temperatures in two ways: via direct convective cooling of the animal and via convective cooling of the substrate, which causes conductive cooling of the animal. The detrimental effect of wind on thermoregulatory effectiveness is surprising, since lizards are expected to thermoregulate more effectively in more challenging habitats. However, wind speed would affect the costs and benefits of thermoregulation in more complex ways than just the cooling of animals and their habitats. For example, it may reduce the daily activity, increase desiccation, or complicate the hunting of prey. Finally, our results imply that wind should also be considered when developing conservation strategies for threatened ectotherms.

  14. Wind constraints on the thermoregulation of high mountain lizards

    Science.gov (United States)

    Ortega, Zaida; Mencía, Abraham; Pérez-Mellado, Valentín

    2017-03-01

    Thermal biology of lizards affects their overall physiological performance. Thus, it is crucial to study how abiotic constraints influence thermoregulation. We studied the effect of wind speed on thermoregulation in an endangered mountain lizard ( Iberolacerta aurelioi). We compared two populations of lizards: one living in a sheltered rocky area and the other living in a mountain ridge, exposed to strong winds. The preferred temperature range of I. aurelioi, which reflects thermal physiology, was similar in both areas, and it was typical of a cold specialist. Although the thermal physiology of lizards and the structure of the habitat were similar, the higher wind speed in the exposed population was correlated with a significant decrease in the effectiveness thermoregulation, dropping from 0.83 to 0.74. Our results suggest that wind reduces body temperatures in two ways: via direct convective cooling of the animal and via convective cooling of the substrate, which causes conductive cooling of the animal. The detrimental effect of wind on thermoregulatory effectiveness is surprising, since lizards are expected to thermoregulate more effectively in more challenging habitats. However, wind speed would affect the costs and benefits of thermoregulation in more complex ways than just the cooling of animals and their habitats. For example, it may reduce the daily activity, increase desiccation, or complicate the hunting of prey. Finally, our results imply that wind should also be considered when developing conservation strategies for threatened ectotherms.

  15. Assessing water resources under climate change in high-altitude catchments: a methodology and an application in the Italian Alps

    Science.gov (United States)

    Aili, T.; Soncini, A.; Bianchi, A.; Diolaiuti, G.; D'Agata, C.; Bocchiola, D.

    2018-01-01

    Assessment of the future water resources in the Italian Alps under climate change is required, but the hydrological cycle of the high-altitude catchments therein is poorly studied and little understood. Hydrological monitoring and modeling in the Alps is difficult, given the lack of first hand, site specific data. Here, we present a method to model the hydrological cycle of poorly monitored high-altitude catchments in the Alps, and to project forward water resources availability under climate change. Our method builds on extensive experience recently and includes (i) gathering data of climate, of cryospheric variables, and of hydrological fluxes sparsely available; (ii) robust physically based glacio-hydrological modeling; and (iii) using glacio-hydrological projections from GCM models. We apply the method in the Mallero River, in the central (Retiche) Alps of Italy. The Mallero river covers 321 km2, with altitude between 310 and 4015 m a.s.l., and it has 27 km2 of ice cover. The glaciers included in the catchment underwent large mass loss recently, thus Mallero is largely paradigmatic of the present situation of Alpine rivers. We set up a spatially explicit glacio-hydrological model, describing the cryospheric evolution and the hydrology of the area during a control run CR, from 1981 to 2007. We then gather climate projections until 2100 from three Global Climate Models of the IPCC AR5 under RCP2.6, RCP4.5, and RCP8.5. We project forward flow statistics, flow components (rainfall, snow melt, ice melt), ice cover, and volume for two reference decades, namely 2045-2054 and 2090-2099. We foresee reduction of the ice bodies from - 62 to - 98% in volume (year 2100 vs year 1981), and subsequent large reduction of ice melt contribution to stream flows (from - 61 to - 88%, 2100 vs CR). Snow melt, now covering 47% of the stream flows yearly, would also be largely reduced (from - 19 to - 56%, 2100 vs CR). The stream flows will decrease on average at 2100 (from + 1 to - 25

  16. Climate impacts on the hydrology of high elevation catchments, Colorado Front Range

    Science.gov (United States)

    Williams, M.; Hill, K.; Caine, N.; Janke, J.

    2009-04-01

    Potential climate impacts on the hydrology of two seasonally snow covered catchments is evaluated using 24 years of data from Niwot Ridge Long Term Ecological Research Site, Colorado. At the larger (220 ha), higher elevation (3570 m) GL4 catchment annual discharge did not change significantly based on nonparametric trend testing. However, October streamflow volumes and groundwater storage did increase, despite drought conditions near the end of the record in 2000-2004. In contrast, at the smaller (8 ha), lower elevation (3400 m) MART catchment, annual discharge decreased significantly over the study period with the most substantial changes in July-September. The study period was separated into "wet", "normal", and "dry" years based on the 75th and 25th quartiles of annual precipitation. Results indicate that MART is particularly sensitive to changes in precipitation with dry years exhibiting decreased snowmelt peak flows, earlier snowmelt timing, decreased annual discharge, and reduced late-season flows. GL4 was less susceptible to changes in precipitation and surprisingly late-season flow volumes (Sept.-Oct.) were not significantly different between wet, normal, and dry conditions. Glacial melt from the Arikaree glacier may account for up to 43% of the increase in late-season flows based on ablation measurements. We downscaled a regional permafrost model based on topoclimatic variables to assess whether subsurface ice within permafrost and rock glaciers could account for the remaining deficiency. Results suggest that with only 1° C of warming over 1/3 of permafrost area would be lost. Over the study period mean annual minimum temperatures increased by 0.6° decade-1, with the some of most prominent increases occurring in July (1.5° C decade-1). Additionally, limited ground temperature measurements at an active rock glacier indicate a 1° C increase over the past decade. This suggests that the source of late-season streamflow at GL4 has shifted towards permafrost

  17. Activation of high-elevation alluvial fans in the Transantarctic Mountains - a proxy for warmth along East Antarctic ice margins

    Science.gov (United States)

    Zamora, F. J.; Lewis, A.; Lepper, K. E.

    2012-12-01

    We examined alluvial fans in the McMurdo Dry Valleys region of the Transantarctic Mountains as a proxy for melt-water production along terrestrial margins of the East Antarctic Ice Sheet. Although melting of ice and snow below about 500 m produces large fans, those with catchments above 1000 m are small and show no evidence for recent surface water flow. Well-developed polygonal patterned ground crosscuts relict channels on fan surfaces indicating that inactivity extends back decades to centuries. This suggests that high-elevation fans record only rare sedimentation events resulting from climatic warmth. A record of melt-water production from these alluvial fans combined with regional climate models will help identify temperature and insolation thresholds needed to produce zones of surface melting on the adjacent ice sheet. This is of critical importance because the IPCC identifies ice surface melting along Antarctic margins as the most poorly understood input in models of future sea-level rise. To create a record of melting events we analyzed six alluvial fans; all with catchments above 1000 m. We focused on internal stratigraphy to identify discreet melt events and on fan catchment area, elevation profile and aspect using GIS analysis. We sampled individual beds to determine depositional ages using optically stimulated luminescence (OSL) dating. The six studied fans consist primarily of well-sorted, cross-bedded gravelly sand with less common interbeds of poorly bedded cobbles in a sandy matrix; total sediment thickness ranged from 0.3 to 1.4 m. Sedimentary textures show that fan-building processes are predominantly fluvial sheet flows and dilute debris flows. Beneath each fan are buried desert pavements comprised of ventifacted clasts. These buried surfaces always separate fan sediments from underlying Miocene-age tills. No ventifacted surfaces were observed within fans suggesting that each of the six sampled fans date to discreet periods of sedimentation

  18. Microbial eukaryote plankton communities of high-mountain lakes from three continents exhibit strong biogeographic patterns.

    Science.gov (United States)

    Filker, Sabine; Sommaruga, Ruben; Vila, Irma; Stoeck, Thorsten

    2016-05-01

    Microbial eukaryotes hold a key role in aquatic ecosystem functioning. Yet, their diversity in freshwater lakes, particularly in high-mountain lakes, is relatively unknown compared with the marine environment. Low nutrient availability, low water temperature and high ultraviolet radiation make most high-mountain lakes extremely challenging habitats for life and require specific molecular and physiological adaptations. We therefore expected that these ecosystems support a plankton diversity that differs notably from other freshwater lakes. In addition, we hypothesized that the communities under study exhibit geographic structuring. Our rationale was that geographic dispersal of small-sized eukaryotes in high-mountain lakes over continental distances seems difficult. We analysed hypervariable V4 fragments of the SSU rRNA gene to compare the genetic microbial eukaryote diversity in high-mountain lakes located in the European Alps, the Chilean Altiplano and the Ethiopian Bale Mountains. Microbial eukaryotes were not globally distributed corroborating patterns found for bacteria, multicellular animals and plants. Instead, the plankton community composition emerged as a highly specific fingerprint of a geographic region even on higher taxonomic levels. The intraregional heterogeneity of the investigated lakes was mirrored in shifts in microbial eukaryote community structure, which, however, was much less pronounced compared with interregional beta-diversity. Statistical analyses revealed that on a regional scale, environmental factors are strong predictors for plankton community structures in high-mountain lakes. While on long-distance scales (>10 000 km), isolation by distance is the most plausible scenario, on intermediate scales (up to 6000 km), both contemporary environmental factors and historical contingencies interact to shift plankton community structures. © 2016 John Wiley & Sons Ltd.

  19. Sources of sediment and phosphorus in stream flow of a highly productive dairy farmed catchment.

    Science.gov (United States)

    McDowell, R W; Wilcock, R J

    2007-01-01

    Both sediment and phosphorus (P) are important contaminants for surface water quality. Knowing the main sources of sediment and P loss within agricultural catchments enables mitigation practices to be better targeted. With this in mind seasonal loads of suspended sediment (SS), dissolved reactive P (DRP), total P (TP), and bioavailable P (BAP) were measured in a low gradient stream draining an intensively farmed New Zealand dairying catchment. Integrating in situ samplers were deployed to collect samples and the results merged with continuous flow data to calculate seasonal loads during 2005 through 2006. Flow rate, SS, and TP concentrations peaked in winter-spring and were lowest in summer-autumn. Concentrations of BAP in trapped sediment were greatest in autumn, contrasting with winter and spring when greater amounts of sediment were trapped, but with lower P enrichment. Analysis of (137)Cs and mixing model output showed that a major source of sediment and associated P in winter and spring was stream banks. Possible causes for this include trampling and destabilization by stock, channel straightening and sediment removal, and removal of riparian trees that stabilize banks. Modelling indicated that overland flow probably from topsoil (but could include sediment from lanes) contributed most sediment during summer and autumn. Remediation aimed at decreasing particulate P inputs to streams should focus on riparian protection measures, such as permanent stock exclusion and planting with shrubs and trees, ensuring runoff from lanes is minimized, and decreasing Olsen P to nearer optimum agronomic levels.

  20. Climate Change Impacts on Ecosystem Services in High Mountain Areas: A Literature Review

    Directory of Open Access Journals (Sweden)

    Ignacio Palomo

    2017-05-01

    Full Text Available High mountain areas are experiencing some of the earliest and greatest impacts of climate change. However, knowledge on how climate change impacts multiple ecosystem services that benefit different stakeholder groups remains scattered in the literature. This article presents a review of the literature on climate change impacts on ecosystem services benefiting local communities and tourists in high mountain areas. Results show a lack of studies focused on the global South, especially where there are tropical glaciers, which are likely to be the first to disappear. Climate change impacts can be classified as impacts on food and feed, water availability, natural hazards regulation, spirituality and cultural identity, aesthetics, and recreation. In turn, climate change impacts on infrastructure and accessibility also affect ecosystem services. Several of these impacts are a direct threat to the lives of mountain peoples, their livelihoods and their culture. Mountain tourism is experiencing abrupt changes too. The magnitude of impacts make it necessary to strengthen measures to adapt to climate change in high mountain areas.

  1. Medical Problems in High Mountain Environments. A Handbook for Medical Officers

    Science.gov (United States)

    1994-02-01

    valvular heart disease , unrevascularized coronary artery disease , pulmonary hypertension, anemia and medications that depress respiration. Any blood...induced medical problems: acute moun- tain sickness (AMS), high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE). Secondary...affecting the performance of soldiers at altitude. DT.N QUALMIBER OF dS 14. SUBJECT TERMS Altitude, Acute Mountain Sickness, Pulmonary Edema, 49

  2. Contrasting trends in hydrologic extremes for two sub-arctic catchments in northern Sweden - Does glacier melt matter?

    Science.gov (United States)

    Dahlke, H. E.; Lyon, S. W.; Stedinger, J. R.; Rosqvist, G.; Jansson, P.

    2012-04-01

    Climate warming in the high-latitude environments of Sweden is raising concerns about its impacts upon hydrology. In order to manage future water resources in these snowmelt-dominated high-latitude and altitude catchments there is a need to determine how climatic change will influence glacial meltwater rates and terrestrial hydrology. This uncertainty is particularly acute for hydrologic extremes (flood events) because understanding the frequency of such unusual events requires long records of observation not often available for high-latitude and altitude catchments. This study presents a statistical analysis of trends in the magnitude and timing of hydrologic extremes (flood events) and the mean summer (June-August) discharge in two sub-arctic catchments, Tarfalajokk and Abiskojokk, in northern Sweden. The catchments have different glacier covers of 30% and 1%, respectively. Statistically significant hydrologic trends (at the 5% level) were identified for both catchments on an annual and on a seasonal scale (3-months averages) using the Mann-Kendall trend test and were related to observed changes in the precipitation and air temperature. Both catchments showed a statistically significant increase in the annual mean air temperature over the comparison time period of 1985-2009 (Tarfalajokk & Abiskojokk pflood peaks and the mean summer discharge. Hydrologic trends indicated an amplification of the hydrologic response in the highly glaciated catchment and a dampening of the response in the non-glaciated catchment. The glaciated mountain catchment showed a statistically significant increasing trend in the mean summer discharge that is clearly correlated to the decrease in glacier mass balance and the increase in air temperature. However, the catchment showed also a significant increase in the flood magnitudes, which are clearly correlated to the occurrence of extreme precipitation events, indicating a shift of the dominant storm runoff mechanism towards rainfall

  3. Crossing thresholds: Analysis of hazardous tipping points in alpine catchments

    Science.gov (United States)

    Lutzmann, Silke; Sass, Oliver

    2016-04-01

    Steep mountain channels or torrents in small alpine catchments are characterized by high geomorphic activity with sediment dynamics being inherently nonlinear and threshold-mediated. Localized, high intensity rainstorms can drive torrential systems past a tipping point resulting in a sudden onset of hazardous events like (flash-) flooding, heavy bedload transport or debris flows. Such responses exhibit an abrupt switch in the fluvial system's mode (e.g. transport / supply limited). Changes in functional connectivity may persist beyond the tipping point. Torrential hazards cause costly damage in the densely populated Alpine Region. Thus, there is a rising interest in potential effects of climate change on torrential sediment dynamics. Understanding critical conditions close to tipping points is important to reduce uncertainty in predicting sediment fluxes. In this study we aim at (i) establishing threshold precipitation characteristics for the Eastern Alps of Austria. Precipitation is hypothesized to be the main forcing factor of torrential events. (ii) How do thresholds vary in space and time? (iii) The effect of external triggers is strongly mediated by the internal disposition of catchments to respond. Which internal conditions are critical for susceptibility? (iv) Is there a change in magnitude or frequency in the recent past and what can be expected for the future? The 71 km2 catchment of the river Schöttlbach in the East Alpine Region of Styria (Austria) is monitored since a heavy precipitation event resulted in a catastrophic flood in July 2011. Sediment mobilization from slopes as well as within-channel storage and bedload transport are regularly measured using photogrammetric methods and sediment impact sensors. Thus, detailed knowledge exists on magnitude and spatial propagation of sediment waves through the catchment. The associated hydro-meteorological (pre-) conditions can be inferred from a dense station network. Changing bedload transport rates and

  4. Analysis and Predictability of the Hydrological Response of Mountain Catchments to Heavy Rain on Snow Events: A Case Study in the Spanish Pyrenees

    Directory of Open Access Journals (Sweden)

    Javier G. Corripio

    2017-03-01

    Full Text Available From 18 to 19 June 2013, the Ésera river in the Pyrenees, Northern Spain, caused widespread damage due to flooding as a result of torrential rains and sustained snowmelt. We estimate the contribution of snow melt to total discharge applying a snow energy balance to the catchment. Precipitation is derived from sparse local measurements and the WRF-ARW model over three nested domains, down to a grid cell size of 2 km. Temperature profiles, precipitation and precipitation gradient are well simulated, although with a possible displacement regarding the observations. Snowpack melting was correctly reproduced and verified in three instrumented sites, and according to satellite images. We found that the hydrological simulations agree well with measured discharge. Snowmelt represented 33% of total runoff during the main flood event and 23% at peak flow. The snow energy balance model indicates that most of the energy for snow melt during the day of maximum precipitation came from turbulent fluxes. This approach forecast correctly peak flow and discharge during normal conditions at least 24 h in advance and could give an early warning of the extreme event 2.5 days before.

  5. Changes in catchment hydrology in relation to vegetation recovery: a comparative modelling experiment

    Science.gov (United States)

    Lana-Renault, Noemí; Karssenberg, Derek; Latron, Jérôme; Serrano, Mā Pilar; Regüés, David; Bierkens, Marc F. P.

    2010-05-01

    Mediterranean mountains have been largely affected by land abandonment and subsequent vegetation recovery, with a general expansion of shrubs and forests. Such a large scale land-cover change has modified the hydrological behavior of these areas, with significant impact on runoff production. Forecasting the trend of water resources under future re-vegetation scenarios is of paramount importance in Mediterranean basins, where water management relies on runoff generated in these areas. With this purpose, a modelling experiment was designed based on the information collected in two neighbouring research catchments with a different history of land use in the central Spanish Pyrenees. One (2.84 km2) is an abandoned agricultural catchment subjected to plant colonization and at present mainly covered by shrubs. The other (0.92 km2) is a catchment covered by dense natural forest, representative of undisturbed environments. Here we present the results of the analysis of the hydrological differences between the two catchments, and a description of the approach and results of the modelling experiment. In a statistical analysis of the field data, significant differences were observed in the streamflow response of the two catchments. The forested catchment recorded fewer floods per year compared to the old agricultural catchment, and its hydrological response was characterised by a marked seasonality, with autumn and spring as the only high flow periods. Stormflow was generally higher in the old agricultural catchment, especially for low to intermediate size events; only for large events the stormflow in the forested catchment was sometimes greater. Under drier conditions, the relative differences in the stormflow between the two catchments tended to increase whereas under wet conditions they tended to be similar. The forested catchment always reacted more slowly to rainfall, with lower peakflows (generally one order of magnitude lower) and longer recession limbs. The modelling

  6. Effects of topographic smoothing on the simulation of winter precipitation in High Mountain Asia

    Science.gov (United States)

    Cannon, Forest; Carvalho, Leila M. V.; Jones, Charles; Norris, Jesse; Bookhagen, Bodo; Kiladis, George N.

    2017-02-01

    Numerous studies have projected future changes in High Mountain Asia water resources based on temperature and precipitation from global circulation models (GCMs) under future climate scenarios. Although the potential benefit of such studies is immense, coarse grid-scale GCMs are unable to resolve High Mountain Asia's complex topography and thus have a biased representation of regional weather and climate. This study investigates biases in the simulation of physical mechanisms that generate snowfall and contribute to snowpack in High Mountain Asia in coarse topography experiments using the Weather Research and Forecasting model. Regional snowpack is event driven, thus 33 extreme winter orographic precipitation events are simulated at fine atmospheric resolution with 6.67 km resolution topography and smoothed 1.85° × 1.25° GCM topography. As with many modified topography experiments performed in other regions, the distribution of precipitation is highly dependent on first-order orographic effects, which dominate regional meteorology. However, we demonstrate that topographic smoothing enhances circulation in simulated extratropical cyclones, with significant impacts on orographic precipitation. Despite precipitation reductions of 28% over the highest ranges, due to reduced ascent on windward slopes, total precipitation over the study domain increased by an average of 9% in smoothed topography experiments on account of intensified extratropical cyclone dynamics and cross-barrier moisture flux. These findings identify an important source of bias in coarse-resolution simulated precipitation in High Mountain Asia, with important implications for the application of GCMs toward projecting future hydroclimate in the region.

  7. The investigation of ground temperatures in high mountain areas using IButtons

    Science.gov (United States)

    Fiddes, Joel; Gubler, Stefanie; Gruber, Stephan; Hungerbühler, Guido; Knecht, Oliver; Sheikh, Suhel; Keller, Matthias; Beutel, Jan

    2010-05-01

    Mountain areas are characterized by extreme variability in elevation, exposure to solar radiation and ground material. Many physical processes, that control ground temperatures and thereby permafrost, are highly affected by this variability. An improved understanding of permafrost and related processes in mountain areas therefore requires investigation at high spatial resolutions. The aim of this project is to investigate ground surface temperatures in high mountain areas. We focus on the effects of topography and local ground properties on surface temperatures at high spatial and temporal resolutions. We distributed 390 mini temperature logger IButtons (www.maxim-ic.com) at Corvatsch in the Upper Engadin (Switzerland) logging surface temperatures at a 3 hour time step. This distributed network of temperature loggers is planned to operate for 3 years. The programming, distribution and recovery of many IButton devices in high mountain areas is very time-consuming. It requires a systematic recording and storage of relevant metadata such as the geographic coordinates of each IButton as well as other topographic characteristics. To easily handle these requirements and to stream-line field work, we developed an effective working procedure and supporting software to program and read-out IButtons (precision, time resolution, etc.) and to store the temperature measurements in a database together with the relevant metadata. The possibility to connect a GPS device and digital camera to this system makes the recording of meta-data and the reclamation of loggers very efficient. We present the project together with the main tools of the developed software.

  8. Yucca Mountain, Nevada - A Proposed Geologic Repository for High-Level Radioactive Waste (Volume 1) Introduction

    Energy Technology Data Exchange (ETDEWEB)

    R.A. Levich; J.S. Stuckless

    2006-09-25

    Yucca Mountain in Nevada represents the proposed solution to what has been a lengthy national effort to dispose of high-level radioactive waste, waste which must be isolated from the biosphere for tens of thousands of years. This chapter reviews the background of that national effort and includes some discussion of international work in order to provide a more complete framework for the problem of waste disposal. Other chapters provide the regional geologic setting, the geology of the Yucca Mountain site, the tectonics, and climate (past, present, and future). These last two chapters are integral to prediction of long-term waste isolation.

  9. Holocene Lake Productivity and Inferred Climate Histories From High-Altitude Sites Within the Baroon Taiga Mountains, Northern Mongolia

    Science.gov (United States)

    Robinson, K. D.; Rosenmeier, M. F.; Ortiz, J. D.

    2007-12-01

    Diffuse reflectance spectroscopy, biogenic silica, and standard loss-on-ignition (LOI) analyses of radiocarbon- dated sediment core samples from Sanjin, Asgat, Ganbold, and Mustei Nuur provide a nearly 11,000 year history of aquatic productivity changes within lakes of the Baroon Taiga Mountains, northern Mongolia. Productivity within these lakes is most sensitive to temperature fluctuations because the catchments are small, nutrient poor, and located at relatively high elevations (greater than 2200 m) with very low annual average temperatures. Within the Mustei Nuur basin, long-term decreases in reflectance and LOI-inferred algal productivity follow orbitally-forced reductions in northern hemisphere solar insolation (i.e., energy receipt) after 8000 years before present (B.P.). Prior to 8000 years ago, enhanced algal productivity within the lake likely reflects increasing northern hemisphere temperature trends following late glacial conditions. Higher frequency (decadal to centennial-scale) changes in biogenic silica, organic matter, and reflectance-inferred algal pigment concentrations within the late Holocene sediment sequences of Sanjin, Asgat, and Ganbold Nuur are interpreted as representing aquatic productivity variations influenced by the length of the ice-free growing season and, by further inference, local temperature variations. Reduced productivity and inferred lower temperatures are documented between 300 and 100 years B.P., roughly coincident with the Little Ice Age, whereas warmer conditions existed from 900-1100 years B.P., and between (roughly) 100 years B.P. and the present. Inferred warming over the last century parallels instrumental data trends, numerous high-latitude (arctic) paleoenvironmental records, and several other notable northern hemisphere temperature reconstructions. Correlations between late Holocene reflectance, biogenic silica, and LOI-inferred aquatic productivity records from the Baroon Taiga alpine lakes and nearby temperature

  10. Gained insights from combined high-frequency and long-term water quality monitoring in agricultural catchments

    Science.gov (United States)

    Jomaa, Seifeddine; Dupas, Rémi; Musolff, Andreas; Rozemeijer, Joachim; Borchardt, Dietrich; Rode, Michael

    2017-04-01

    Despite extensive efforts to reduce nitrate (NO3) transfer in agricultural areas, the NO3 concentration in rivers often changes little. To investigate the reasons for this limited response, NO3 dynamics in a 100 km2 agricultural catchment in eastern Germany was analysed from decadal to infra-hourly time scales. First, Dynamic Harmonic Regression (DHR) analysis of a 32-year (1982-2014) record of NO3 and discharge revealed that i) the long-term trend in NO3 concentration was closely related to that in discharge, suggesting that large-scale weather and climate patterns were masking the effect of improved nitrogen management on NO3 trends; ii) maximum winter and minimum summer concentrations had a persistent seasonal pattern, which was interpreted as a dynamic NO3 concentration from the soil and subsoil columns; and iii) the catchment progressively changed from chemodynamic to more chemostatic behaviour over the three decades of study, which is a sign of long-term homogenisation of NO3 concentrations in the profile. Second, infra-hourly (15 min time interval) analysis of storm-event dynamics during a typical hydrological year (2005-2006) was performed to identify periods of the year with high leaching risk and to link the latter to agricultural management practices in the catchment. Also, intra-hourly data was used to improve NO3 load estimation during storm events. An Event Response Reconstruction (ERR) model was built using NO3 concentration response descriptor variables and predictor variables deduced from discharge and precipitation records. The ERR approach significantly improved NO3 load estimates compared to linear interpolation of grab-sampling data (error was reduced from 10 to 1%). Finally, this study shows that detailed physical understanding of NO3 dynamics across time scales can be obtained only through combined analysis of long-term records and high-resolution sensor data. Hence, a joint effort is advocated between environmental authorities, who usually

  11. Displacement and Revitalization of the Nahuatl Language in the High Mountains of Veracruz, Mexico

    Science.gov (United States)

    Sandoval Arenas, Carlos O.

    2017-01-01

    This article focuses on language displacement in the High Mountains of Central Veracruz. It begins by presenting a brief historical account of the Nahuatl presence in the region in order to distinguish this group from other Nahuatl-speaking groups. Later, it describes the situation of language loss that is currently underway and argues that the…

  12. Chemical evolution of a high-level magma system: the Black Mountain volcanic center, southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, T.A.; Noble, D.C.; Younker, L.W.

    1983-09-01

    A comprehensive study of stratigraphically controlled samples of both lavas and ash-flow tuffs from the Black Mountain volcanic center enables us to evaluate magmatic processes. The results of this study are used to: (1) determine how this high-level magma system developed; (2) compare this system with other similar systems; and (3) correlate ash-flow sheets using their chemical characteristics.

  13. The role of catchment characteristics in determining surface water nitrogen in four upland regions in the UK

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available Hydrochemical and catchment data from 80 upland moorland sites in four regions with contrasting climate, soils, geology and geomorphology have been analysed to assess the key catchment attributes that influence enhanced leaching of soluble nitrogen to surface waters. The regions are the South Pennines of northern England, the Snowdonia National Park in north Wales, the Galloway region of south-west Scotland and the Mourne Mountains in Northern Ireland, all highly acidified, with median pH values of 3−, ammonium (NH4+, dissolved organic nitrogen (DON and dissolved organic carbon (DOC were expressed as functions of catchment attributes. Nitrate concentrations in waters draining catchments dominated by peaty soils (large C pool were much less than those in catchments dominated by mineral soils (small C pool. Hence, if future N deposition levels are maintained or increase, high-altitude catchments with small carbon pools are potentially more susceptible to NO3− leaching. All N species exhibit seasonality; this is most marked in Galloway and least marked in the South Pennines, which implies that the South Pennines have reached an advanced stage of N saturation. Surface water inorganic N concentrations and the ratio of dissolved organic carbon (DOC to dissolved organic N (DON can be related to deposition inputs, although relationships differ throughout the year. If the DOC/DON ratio is indicative of catchment N saturation, levels of N retention are at least partially determined by deposition levels. This study identifies N deposition as a major inter-regional control on the degree of catchment N saturation and on N leaching to surface waters; it stresses the importance of catchment factors in modifying the relationship between N deposition and leaching in acid sensitive UK upland catchments.

  14. Late Holocene High Discharge and Erosion Events Inferred from Sediment Proxies and Catchment Geomorphology, Lake Vuoksjávrátje, NW Sweden

    Science.gov (United States)

    Berntsson, A.; Jansson, K. N.; Kylander, M. E.; De Vleeschouwer, F.; Bertrand, S.

    2014-12-01

    Alpine lakes in NW Sweden are highly sensitive to variations in catchment erosion and in precipitation. Previous studies aimed at reconstructing past summer temperatures have suggested that this sensitivity may influence chironomid species composition enough to cause bias in quantitative temperature reconstructions. In this study we have analysed lake sediments covering the last 5100 years from Lake Vuoksjávrátje in NW Sweden and catchment geomorphology with the aim to separate between different erosional regimes in the lake and its catchment and to identify sediment sources and processes behind sediment deposition in the lake basin. Methods include XRF core scanning, grain size analysis, chironomid analysis, TOC and C/N analysis and detailed mapping of geomorphology. From the integrated results we identify time intervals with increased catchment erosion, inferred to result from intense precipitation. Based on the combined proxy data it was concluded that a major flood event took place at the Vindelfjällen site c. 2800 cal BP, unique for the 5100-year long record. The chironomid species composition shows stronger influence from wetland surface erosion at c. 2800 cal BP and during the last c. 1000 years. By combining multi-proxy lake sediment analysis with study of catchment geomorphology it is possible to improve the understanding of Late Holocene hydro-climatic change and how it may influence Arctic alpine lakes.

  15. A mechanistic assessment of nutrient flushing at the catchment scale

    Science.gov (United States)

    Willem J. van Verseveld; Jeffrey J. McDonnell; Kate Lajtha

    2008-01-01

    This paper mechanistically assesses the flushing mechanism of DOC, DON, and DIN at the hillslope and catchment scales during two storm events, in a small catchment (WS10), H.J. Andrews Experimental Forest in the western Cascade Mountains of Oregon. Using a combination of natural tracer and hydrometric data, and end-member mixing analysis, we were able to describe the...

  16. Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment

    Directory of Open Access Journals (Sweden)

    M. Rogora

    2001-01-01

    Full Text Available The Lake Maggiore catchment is the area of Italy most affected by acid deposition. Trend analysis was performed on long-term (15-30 years series of chemical analyses of atmospheric deposition, four small rivers draining forested catchments and four high mountain lakes. An improvement in the quality of atmospheric deposition was detected, due to decreasing sulphate concentration and increasing pH. Similar trends were also found in high mountain lakes and in small rivers. Atmospheric deposition, however, is still providing a large and steady flux of nitrogen compounds (nitrate and ammonium which is causing increasing nitrogen saturation in forest ecosystems and increasing nitrate levels in rivers. Besides atmospheric deposition, an important factor controlling water acidification and recovery is the weathering of rocks and soils which may be influenced by climate warming. A further factor is the episodic deposition of Saharan calcareous dust which contributes significantly to base cation deposition. Keywords: trend, atmospheric deposition, nitrogen, stream water chemistry.

  17. Estimating subsurface water volumes and transit times in Hokkaido river catchments, Japan, using high-accuracy tritium analysis

    Science.gov (United States)

    Gusyev, Maksym; Yamazaki, Yusuke; Morgenstern, Uwe; Stewart, Mike; Kashiwaya, Kazuhisa; Hirai, Yasuyuki; Kuribayashi, Daisuke; Sawano, Hisaya

    2015-04-01

    The goal of this study is to estimate subsurface water transit times and volumes in headwater catchments of Hokkaido, Japan, using the New Zealand high-accuracy tritium analysis technique. Transit time provides insights into the subsurface water storage and therefore provides a robust and quick approach to quantifying the subsurface groundwater volume. Our method is based on tritium measurements in river water. Tritium is a component of meteoric water, decays with a half-life of 12.32 years, and is inert in the subsurface after the water enters the groundwater system. Therefore, tritium is ideally suited for characterization of the catchment's responses and can provide information on mean water transit times up to 200 years. Only in recent years has it become possible to use tritium for dating of stream and river water, due to the fading impact of the bomb-tritium from thermo-nuclear weapons testing, and due to improved measurement accuracy for the extremely low natural tritium concentrations. Transit time of the water discharge is one of the most crucial parameters for understanding the response of catchments and estimating subsurface water volume. While many tritium transit time studies have been conducted in New Zealand, only a limited number of tritium studies have been conducted in Japan. In addition, the meteorological, orographic and geological conditions of Hokkaido Island are similar to those in parts of New Zealand, allowing for comparison between these regions. In 2014, three field trips were conducted in Hokkaido in June, July and October to sample river water at river gauging stations operated by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT). These stations have altitudes between 36 m and 860 m MSL and drainage areas between 45 and 377 km2. Each sampled point is located upstream of MLIT dams, with hourly measurements of precipitation and river water levels enabling us to distinguish between the snow melt and baseflow contributions

  18. High spatial-temporal resolution and integrated surface and subsurface precipitation-runoff modelling for a small stormwater catchment

    Science.gov (United States)

    Hailegeorgis, Teklu T.; Alfredsen, Knut

    2018-02-01

    Reliable runoff estimation is important for design of water infrastructure and flood risk management in urban catchments. We developed a spatially distributed Precipitation-Runoff (P-R) model that explicitly represents the land cover information, performs integrated modelling of surface and subsurface components of the urban precipitation water cycle and flow routing. We conducted parameter calibration and validation for a small (21.255 ha) stormwater catchment in Trondheim City during Summer-Autumn events and season, and snow-influenced Winter-Spring seasons at high spatial and temporal resolutions of respectively 5 m × 5 m grid size and 2 min. The calibration resulted in good performance measures (Nash-Sutcliffe efficiency, NSE = 0.65-0.94) and acceptable validation NSE for the seasonal and snow-influenced periods. The infiltration excess surface runoff dominates the peak flows while the contribution of subsurface flow to the sewer pipes also augments the peak flows. Based on the total volumes of simulated flow in sewer pipes (Qsim) and precipitation (P) during the calibration periods, the Qsim/P ranges from 21.44% for an event to 56.50% for the Winter-Spring season, which are in close agreement with the observed volumes (Qobs/P). The lowest percentage of precipitation volume that is transformed to the total simulated runoff in the catchment (QT) is 79.77%. Computation of evapotranspiration (ET) indicated that the ET/P is less than 3% for the events and snow-influenced seasons while it is about 18% for the Summer-Autumn season. The subsurface flow contribution to the sewer pipes are markedly higher than the total surface runoff volume for some events and the Summer-Autumn season. The peakiest flow rates correspond to the Winter-Spring season. Therefore, urban runoff simulation for design and management purposes should include two-way interactions between the subsurface runoff and flow in sewer pipes, and snow-influenced seasons. The developed urban P-R model is

  19. Bacterial GDGTs in Holocene sediments and catchment soils of a high Alpine lake: application of the MBT/CBT-paleothermometer

    Directory of Open Access Journals (Sweden)

    H. Niemann

    2012-05-01

    Full Text Available A novel proxy for continental mean annual air temperature (MAAT and soil pH, the MBT/CBT-paleothermometer, is based on the temperature (T and pH-dependent distribution of specific bacterial membrane lipids (branched glycerol dialkyl glycerol tetraethers – GDGTs in soil organic matter. Here, we tested the applicability of the MBT/CBT-paleothermometer to sediments from Lake Cadagno, a high Alpine lake in southern Switzerland with a small catchment of 2.4 km2. We analysed the distribution of bacterial GDGTs in catchment soils and in a radiocarbon-dated sediment core from the centre of the lake, covering the past 11 000 yr. The distribution of bacterial GDGTs in the catchment soils is very similar to that in the lake's surface sediments, indicating a common origin of the lipids. Consequently, their transfer from the soils into the sediment record seems undisturbed, probably without any significant alteration of their distribution through in situ production in the lake itself or early diagenesis of branched GDGTs. The MBT/CBT-inferred MAAT estimates from soils and surface sediments are in good agreement with instrumental values for the Lake Cadagno region (~0.5 °C. Moreover, downcore MBT/CBT-derived MAAT estimates match in timing and magnitude other proxy-based T reconstructions from nearby locations for the last two millennia. Major climate anomalies recorded by the MBT/CBT-paleothermometer are, for instance, the Little Ice Age (~14th to 19th century and the Medieval Warm Period (MWP, ~9th to 14th century. Together, our observations indicate the quantitative applicability of the MBT/CBT-paleothermometer to Lake Cadagno sediments. In addition to the MWP, our lacustrine paleo T record indicates Holocene warm phases at about 3, 5, 7 and 11 kyr before present, which agrees in timing with other records from both the Alps and the sub-polar North-East Atlantic Ocean. The good temporal match of the warm periods determined

  20. A synoptic survey of ecosystem services from headwater catchments in the United States

    Science.gov (United States)

    Brian H. Hill; Randall K. Kolka; Frank H. McCormick; Matthew A. Starry

    2014-01-01

    Ecosystem production functions for water supply, climate regulation, and water purification were estimated for 568 headwater streams and their catchments. Results are reported for nine USA ecoregions. Headwater streams represented 74-80% of total catchment stream length. Water supply per unit catchment area was highest in the Northern Appalachian Mountains ecoregion...

  1. Geology of the Yucca Mountain Region, Chapter in Stuckless, J.S., ED., Yucca Mountain, Nevada - A Proposed Geologic Repository for High-Level Radioactive Waste

    Energy Technology Data Exchange (ETDEWEB)

    J.S. Stuckless; D. O' Leary

    2006-09-25

    Yucca Mountain has been proposed as the site for the Nation's first geologic repository for high-level radioactive waste. This chapter provides the geologic framework for the Yucca Mountain region. The regional geologic units range in age from late Precambrian through Holocene, and these are described briefly. Yucca Mountain is composed dominantly of pyroclastic units that range in age from 11.4 to 15.2 Ma. The proposed repository would be constructed within the Topopah Spring Tuff, which is the lower of two major zoned and welded ash-flow tuffs within the Paintbrush Group. The two welded tuffs are separated by the partly to nonwelded Pah Canyon Tuff and Yucca Mountain Tuff, which together figure prominently in the hydrology of the unsaturated zone. The Quaternary deposits are primarily alluvial sediments with minor basaltic cinder cones and flows. Both have been studied extensively because of their importance in predicting the long-term performance of the proposed repository. Basaltic volcanism began about 10 Ma and continued as recently as about 80 ka with the eruption of cones and flows at Lathrop Wells, approximately 10 km south-southwest of Yucca Mountain. Geologic structure in the Yucca Mountain region is complex. During the latest Paleozoic and Mesozoic, strong compressional forces caused tight folding and thrust faulting. The present regional setting is one of extension, and normal faulting has been active from the Miocene through to the present. There are three major local tectonic domains: (1) Basin and Range, (2) Walker Lane, and (3) Inyo-Mono. Each domain has an effect on the stability of Yucca Mountain.

  2. Spatiotemporal dynamics of spring and stream water chemistry in a high-mountain area

    Energy Technology Data Exchange (ETDEWEB)

    Zelazny, Miroslaw, E-mail: miroslaw.zelazny@uj.edu.pl [Jagiellonian University, Institute of Geography and Spatial Management, Department of Hydrology, 7 Gronostajowa Str., 30-387 Cracow (Poland); Astel, Aleksander, E-mail: astel@apsl.edu.pl [Environmental Chemistry Research Unit, Biology and Environmental Protection Institute, Pomeranian Academy, 22a Arciszewskiego Str., Slupsk, 76-200 (Poland); Wolanin, Anna [Jagiellonian University, Institute of Geography and Spatial Management, Department of Hydrology, 7 Gronostajowa Str., 30-387 Cracow (Poland); Malek, Stanislaw, E-mail: rlmalek@cyf-kr.edu.pl [Department of Forest Ecology, Forest Faculty, Agricultural University of Cracow, 46 29 Listopada Ave., Cracow, 31-425 (Poland)

    2011-05-15

    The present study deals with the application of the self-organizing map (SOM) technique in the exploration of spatiotemporal dynamics of spring and stream water samples collected in the Chocholowski Stream Basin located in the Tatra Mountains (Poland). The SOM-based classification helped to uncover relationships between physical and chemical parameters of water samples and factors determining the quality of water in the studied high-mountain area. In the upper part of the Chocholowski Stream Basin, located on the top of the crystalline core of the Tatras, concentrations of the majority of ionic substances were the lowest due to limited leaching. Significantly higher concentration of ionic substances was detected in spring and stream samples draining sedimentary rocks. The influence of karst-type springs on the quality of stream water was also demonstrated. - Highlights: > We use SOM approach to explore physiochemical data for mountain waters. > Geologic structure and hydrological events impact water chemistry. > Limited leaching, typical of crystalline core, reflects in low water mineralization. > Sedimentary rocks are susceptible for leaching. > Eutrophication has not been shown to be a threat in the Chocholowska Valley. - Spatiotemporal dynamics of spring and stream water chemistry in unique high-mountain area was evaluated by the self-organizing map technique.

  3. Hydraulics and morphology of mountain rivers; literature survey

    NARCIS (Netherlands)

    Sieben, J.

    1993-01-01

    Present knowledge on fluvial processes in mountain rivers should be expanded to enable the development of projects dealing with mountain rivers or mountain-river catchment areas. This study reviews research on hydraulic and morphological features of mountain rivers. A major characteristic of

  4. Hydrologic connectivity between landscapes and streams: Transferring reach- and plot-scale understanding to the catchment scale

    Science.gov (United States)

    Jencso, K.G.; McGlynn, B.L.; Gooseff, M.N.; Wondzell, S.M.; Bencala, K.E.; Marshall, L.A.

    2009-01-01

    The relationship between catchment structure and runoff characteristics is poorly understood. In steep headwater catchments with shallow soils the accumulation of hillslope area (upslope accumulated area (UAA)) is a hypothesized first-order control on the distribution of soil water and groundwater. Hillslope-riparian water table connectivity represents the linkage between the dominant catchment landscape elements (hillslopes and riparian zones) and the channel network. Hydrologic connectivity between hillslope-riparian-stream (HRS) landscape elements is heterogeneous in space and often temporally transient. We sought to test the relationship between UAA and the existence and longevity of HRS shallow groundwater connectivity. We quantified water table connectivity based on 84 recording wells distributed across 24 HRS transects within the Tenderfoot Creek Experimental Forest (U.S. Forest Service), northern Rocky Mountains, Montana. Correlations were observed between the longevity of HRS water table connectivity and the size of each transect's UAA (r2 = 0.91). We applied this relationship to the entire stream network to quantify landscape-scale connectivity through time and ascertain its relationship to catchment-scale runoff dynamics. We found that the shape of the estimated annual landscape connectivity duration curve was highly related to the catchment flow duration curve (r2 = 0.95). This research suggests internal catchment landscape structure (topography and topology) as a first-order control on runoff source area and whole catchment response characteristics. Copyright 2009 by the American Geophysical Union.

  5. Source limitation of carbon gas emissions in high-elevation mountain streams and lakes

    Science.gov (United States)

    Crawford, John T.; Dornblaser, Mark M.; Stanley, Emily H.; Clow, David W.; Striegl, Robert G.

    2015-01-01

    Inland waters are an important component of the global carbon cycle through transport, storage, and direct emissions of CO2 and CH4 to the atmosphere. Despite predictions of high physical gas exchange rates due to turbulent flows and ubiquitous supersaturation of CO2—and perhaps also CH4—patterns of gas emissions are essentially undocumented for high mountain ecosystems. Much like other headwater networks around the globe, we found that high-elevation streams in Rocky Mountain National Park, USA, were supersaturated with CO2 during the growing season and were net sources to the atmosphere. CO2concentrations in lakes, on the other hand, tended to be less than atmospheric equilibrium during the open water season. CO2 and CH4 emissions from the aquatic conduit were relatively small compared to many parts of the globe. Irrespective of the physical template for high gas exchange (high k), we found evidence of CO2 source limitation to mountain streams during the growing season, which limits overall CO2emissions. Our results suggest a reduced importance of aquatic ecosystems for carbon cycling in high-elevation landscapes having limited soil development and high CO2 consumption via mineral weathering.

  6. Hart Mountain - Protecting High Value Shrub-steppe Habitat

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In fiscal year 2012 a high capacity skid-mounted spray system and herbicide was purchased. A contract for herbicide application was awarded to a local non-profit...

  7. Headwater sediment dynamics in a debris flow catchment constrained by high-resolution topographic surveys

    Science.gov (United States)

    Loye, Alexandre; Jaboyedoff, Michel; Theule, Joshua Isaac; Liébault, Frédéric

    2016-06-01

    Debris flows have been recognized to be linked to the amounts of material temporarily stored in torrent channels. Hence, sediment supply and storage changes from low-order channels of the Manival catchment, a small tributary valley with an active torrent system located exclusively in sedimentary rocks of the Chartreuse Massif (French Alps), were surveyed periodically for 16 months using terrestrial laser scanning (TLS) to study the coupling between sediment dynamics and torrent responses in terms of debris flow events, which occurred twice during the monitoring period. Sediment transfer in the main torrent was monitored with cross-section surveys. Sediment budgets were generated seasonally using sequential TLS data differencing and morphological extrapolations. Debris production depends strongly on rockfall occurring during the winter-early spring season, following a power law distribution for volumes of rockfall events above 0.1 m3, while hillslope sediment reworking dominates debris recharge in spring and autumn, which shows effective hillslope-channel coupling. The occurrence of both debris flow events that occurred during the monitoring was linked to recharge from previous debris pulses coming from the hillside and from bedload transfer. Headwater debris sources display an ambiguous behaviour in sediment transfer: low geomorphic activity occurred in the production zone, despite rainstorms inducing debris flows in the torrent; still, a general reactivation of sediment transport in headwater channels was observed in autumn without new debris supply, suggesting that the stored debris was not exhausted. The seasonal cycle of sediment yield seems to depend not only on debris supply and runoff (flow capacity) but also on geomorphic conditions that destabilize remnant debris stocks. This study shows that monitoring the changes within a torrent's in-channel storage and its debris supply can improve knowledge on recharge thresholds leading to debris flow.

  8. Estimation of the limitations for surficial water addition above a potential high level radioactive waste repository at Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

    Energy Technology Data Exchange (ETDEWEB)

    Fewell, M.E.; Sobolik, S.R.; Gauthier, J.H.

    1992-01-01

    The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface-based and underground testing. Analyses have been performed to design site characterization activities with minimal impact on the ability of the site to isolate waste, and on tests performed as part of the characterization process. One activity of site characterization is the construction of an Exploratory Studies Facility, consisting of underground shafts, drifts, and ramps, and the accompanying surface pad facility and roads. The information in this report addresses the following topics: (1) a discussion of the potential effects of surface construction water on repository-performance, and on surface and underground experiments; (2) one-dimensional numerical calculations predicting the maximum allowable amount of water that may infiltrate the surface of the mountain without affecting repository performance; and (3) two-dimensional numerical calculations of the movement of that amount of surface water and how the water may affect repository performance and experiments. The results contained herein should be used with other site data and scientific/engineering judgement in determining controls on water usage at Yucca Mountain. This document contains information that has been used in preparing Appendix I of the Exploratory Studies Facility Design Requirements document for the Yucca Mountain Site Characterization Project.

  9. AN ANALYSIS OF IODINE DEFICIENCY DISORDER AND ERADICATION STRATEGIES IN THE HIGH ATLAS MOUNTAINS OF MOROCCO

    OpenAIRE

    Oldham, Elizabeth Anne; Barrett, Christopher B.; Benjelloun, Sabah; Ahanou, Brahim

    1996-01-01

    The population of the Ounein Valley in the High Atlas Mountains in Morocco is at high risk of iodine deficiency. We investigated local childrens iodine deficiency and goiter patterns as well as food consumption habits through a household survey. Median urinary iodine content and goiter analysis both reflect moderate iodine deficiency. Total fish consumption has a statistically significant, positive effect on urinary iodine content. Fish consumption, like that of salt, is closely related to ma...

  10. Hydrology in a mediterranean mountain environment. The Vallcebre research catchment (north eastern Spain) I. 20 years of investigations of hydrological dynamics; Hidrologia de un ambiente Mediterraneo de montana. Las cuencas de Vallcebre (Pirineo Oriental) I. 20 anos de investigaciones hidrologicas

    Energy Technology Data Exchange (ETDEWEB)

    Latron, J.; Llorens, P.; Solar, M.; Poyatos, R.; Rubio, C.; Muzylo, A.; Martinez-Carreras, N.; Delgado, J.; Regues, D.; Catari, G.; Nord, G.; Gallart, F.

    2009-07-01

    Investigations started 20 years ago in the Vallcebre research basins with the objectives of better understanding the hydrological functioning of Mediterranean mountains basins. The Vallcebre basins (0.15-4.17 km{sup 2}) are located in a Mediterranean mountain area of the Pyrenean ranges (1300 m.a.s.l., North Eastern Spain) Average annual precipitations 862{+-} 260 mm and potential evapotranspiration is 823{+-}26mm. Climate is highly seasonal leading to periods with water deficit in summer, and eventually in winter. Hydrological investigations to periods with water deficit in summer, and eventually in winter. Hydrological investigations in the basins are related to rainfall interception, evapotranspiration, soil moisture spatio-temporal dynamics, runoff response and runoff processes, suspended sediment dynamics and model application both at the plot and basin scales. (Author) 15 refs.

  11. Microclimatic differences in habitat on a high mountain in the ...

    African Journals Online (AJOL)

    A study of the effect of altitude and aspect of a 610 m high inselberg indicates that each of these factors has ecologically important influences on temperature, evaporation and humidity. Measurements of the microclimatic differences between six stations demonstrated that by the action of both adiabatic cooling and ...

  12. Trend analysis of nutrient loadings in the South Saskatchewan River catchment

    Science.gov (United States)

    Morales-Marin, L. A.; Chun, K. P.; Wheater, H. S.; Lindenschmidt, K. E.

    2015-12-01

    Nutrient loadings in river catchments have increased in the past years as a consequence of rapid expansion of agricultural areas, new urban developments and industries, and population growth. Nutrient enrichment of water bodies has intensified eutrophication conditions that degrade water quality and ecosystem health. In large-scale catchments, the assessment of temporal and spatial variability of nutrient loads imply challenges due to climate, land use and geology heterogeneity, and to anthropogenic changes. In this study we carried out a trend analysis of total phosphorus and total nitrogen loads in the South Saskatchewan River (SSR) catchment. This catchment is located in the Canadian Prairie Provinces of Alberta and Saskatchewan. The eastern and central areas of the catchment consist mostly of croplands, pasture lands and livestock farms, whereas the western parts are located on the Rocky Mountains that are the source of most of the catchment's streamflows. The trend analysis was performed applying a novel approach to analyse nutrient time series recorded at long-term water quality stations along the main stems of the SSR river network. Since water quality is taken infrequently, in the proposed approach the time series were complemented using regression analysis methods based on streamflow data recorded at the nearest gauge stations. The time series were subsequently pre-whitened in order to remove the autocorrelation, and then subjected to non-parametric statistical test to detect trends. Seasonal analysis of trends at each of the water quality stations were performed in order to determine the relationships between annual flow regimes and nutrient loads in the catchment, in particular, the influence of the high spring runoff on nutrient export. Decadal analysis was also performed to determine the long-tern relationships of nutrients with anthropogenic changes in the catchment. In particular, the capacity of reservoirs to trap nutrients and the effects of the

  13. High energy nucleonic component of cosmic rays at mountain altitudes

    CERN Document Server

    Stora, Raymond Félix

    The diffusion equations describing the unidimensional propagation of .the high energy nucleonic component of cosmic rays throughout the atmosphere are sol"V'ed under two assumptions: (l) The nucleon-nucleon collisions are described according to Fermi's therlnOdynamical model involving completely inelastic pion and.nucleon-antinucleon pair production. (2) A somewhat opposite assumption is made assuming partially elastic collisions without nucleon-anti.nucleon pair production. Due to the present inaccuracy of experiments, we are able to derive only tentati v.e conclusions. The values computed under both hypotheses for the absorption mean free path and the charged to neutral particles ratio are found in acceptable ranges when compared to experimental data. The diffeential energy spectrum at a given depth is always found steeper than the primary, and steeper than indicated by experimental values if the primary is taken proportional to the 2.5 inverse power of energy.

  14. The Progamic Phase in High-Mountain Plants: From Pollination to Fertilization in the Cold

    Directory of Open Access Journals (Sweden)

    Gerlinde Steinacher

    2013-06-01

    Full Text Available In high-mountains, cold spells can occur at any time during the growing season and plants may be covered with snow for several days. This raises the question to what extent sexual processes are impaired by low temperatures. We tested pollen performance and fertilization capacity of high-mountain species with different elevational distribution in the European Alps (Cerastium uniflorum, Gentianella germanica, Ranunculus glacialis, R. alpestris, Saxifraga bryoides, S. caesia, S. moschata during simulated cold snaps in the laboratory. Plants were exposed to 0 °C (the temperature below the snow for 12, 36, 60 and 84 h. In S. caesia, the experiment was verified in situ during a cold snap. Sexual processes coped well with large temperature differences and remained functional at near-freezing temperatures for a few days. During the cooling-down phase a high percentage (67–97% of pollen grains germinated and grew tubes into the style. At zero degrees, tube growth continued slowly both in the laboratory and in situ below the snow. Fertilization occurred in up to 100% of flowers in the nival species and in G. germanica, but was strongly delayed or absent in the alpine species. During rewarming, fertilization continued. Overall, progamic processes in high-mountain plants appear fairly robust toward weather extremes increasing the probability of successful reproduction.

  15. Long-term, high-frequency water quality monitoring in an agricultural catchment: insights from spectral analysis

    Science.gov (United States)

    Aubert, Alice; Kirchner, James; Faucheux, Mikael; Merot, Philippe; Gascuel-Odoux, Chantal

    2013-04-01

    measurements. At higher frequencies, however, the spectra steepen to a slope of -2, indicating that at sub-daily time scales the concentration time series become relatively smooth. However, at time scales shorter than 2-3 hours, the spectra flatten to a slope near zero (white noise), reflecting analytical noise in the measurement probe. This result demonstrates that measuring water quality dynamics at high frequencies also requires high measurement precision, because as measurements are taken closer and closer together in time, the real-world differences that must be measured between adjacent measurements become smaller and smaller. Our results highlight the importance of quantifying the spectral properties of analytical noise in environmental measurements, to identify frequency ranges where measurements could be dominated by analytical noise instead of real-world signals. 1. Kirchner, J.W., Feng, X., Neal, C., Robson, A.J., 2004. The fine structure of water-quality dynamics: the (high-frequency) wave of the future. Hydrological Processes, 18(7): 1353-1359 2. Aubert, A.H. et al., 2012. The chemical signature of a livestock farming catchment: synthesis from a high-frequency multi-element long term monitoring. HESSD, 9(8): 9715 - 9741 3. Kirchner, J.W. and Neal, C., 2013. Universal fractal scaling in water quality dynamics across the periodic table. Manuscript in review.

  16. Metabolic processes sustaining the reviviscence of lichen Xanthoria elegans (Link) in high mountain environments.

    OpenAIRE

    Aubert, Serge; Juge, Christine; Boisson, Anne-Marie; Gout, Elisabeth; Bligny, Richard

    2007-01-01

    International audience; To survive in high mountain environments lichens must adapt themselves to alternating periods of desiccation and hydration. Respiration and photosynthesis of the foliaceous lichen, Xanthoria elegans, in the dehydrated state were below the threshold of CO2-detection by infrared gas analysis. Following hydration, respiration totally recovered within seconds and photosynthesis within minutes. In order to identify metabolic processes that may contribute to the quick and ef...

  17. Soil physical properties of high mountain fields under bauxite mining

    Directory of Open Access Journals (Sweden)

    Dalmo Arantes de Barros

    2013-10-01

    Full Text Available Mining contributes to the life quality of contemporary society, but can generate significant impacts, these being mitigated due to environmental controls adopted. This study aimed to characterize soil physical properties in high-altitude areas affected by bauxite mining, and to edaphic factors responses to restoration techniques used to recover mined areas in Poços de Caldas plateau, MG, Brazil. The experiment used 3 randomized block design involving within 2 treatments (before mining intervention and after environmental recovery, and 4 replicates (N=24. In each treatment, soil samples with deformed structures were determined: granulometry, water-dispersible clay content, flocculation index, particle density, stoniness level, water aggregate stability, and organic matter contend. Soil samples with preserved structures were used to determine soil density and the total volume of pores, macropores, and micropores. Homogenization of stoniness between soil layers as a result of soil mobilization was observed after the mined area recovery. Stoniness decreased in 0.10-0.20 m layer after recovery, but was similar in the 0-0.10 m layer in before and after samples. The recovery techniques restored organic matter levels to pre-mining levels. However, changes in soil, including an increase in soil flocculation degree and a decrease in water-dispersible clays, were still apparent post-recovery. Furthermore, mining operations caused structural changes to the superficial layer of soil, as demonstrated by an increase in soil density and a decrease in total porosity and macroporosity. Decreases in the water stability of aggregates were observed after mining operations.

  18. The Impact Snow Albedo Feedback over Mountain Regions as Examined through High-Resolution Regional Climate Change Experiments over the Rocky Mountains

    Science.gov (United States)

    Letcher, Theodore

    As the climate warms, the snow albedo feedback (SAF) will play a substantial role in shaping the climate response of mid-latitude mountain regions with transient snow cover. One such region is the Rocky Mountains of the western United States where large snow packs accumulate during the winter and persist throughout the spring. In this dissertation, the Weather Research and Forecast model (WRF) configured as a regional climate model is used to investigate the role of the SAF in determining the regional climate response to forced anthropogenic climate change. The regional effects of climate change are investigated by using the pseudo global warming (PGW) framework, which is an experimental configuration in a which a mean climate perturbation is added to the boundary forcing of a regional model, thus preserving the large-scale circulation entering the region through the model boundaries and isolating the mesoscale climate response. Using this framework, the impact of the SAF on the regional energetics and atmospheric dynamics is examined and quantified. Linear feedback analysis is used to quantify the strength of the SAF over the Headwaters region of the Colorado Rockies for a series of high-resolution PGW experiments. This technique is used to test sensitivity of the feedback strength to model resolution and land surface model. Over the Colorado Rockies, and integrated over the entire spring season, the SAF strength is largely insensitive to model resolution, however there are more substantial differences on the sub-seasonal (monthly) timescale. In contrast, the SAF strength over this region is very sensitive to choice of land surface model. These simulations are also used to investigate how spatial and diurnal variability in warming caused by the SAF influences the dynamics of thermally driven mountain-breeze circulations. It is shown that, the SAF causes stronger daytime mountain-breeze circulations by increasing the warming on the mountains slopes thus enhancing

  19. High-resolution monitoring of stormwater quality in an urbanising catchment in the United Kingdom during the 2013/2014 winter storms

    Science.gov (United States)

    McGrane, S. J.; Hutchins, M. G.; Kjeldsen, T. R.; Miller, J. D.; Bussi, G.; Loewenthal, M.

    2015-12-01

    Urban areas are widely recognised as a key source of contaminants entering our freshwater systems, yet in spite of this, our understanding of stormwater quality dynamics remains limited. The development of in-situ, high-resolution monitoring equipment has revolutionised our capability to capture flow and water quality data at a sub-hourly resolution, enabling us to potentially enhance our understanding of hydrochemical variations from contrasting landscapes during storm events. During the winter of 2013/2014, the United Kingdom experienced a succession of intense storm events, where the south of the country experienced 200% of the average rainfall, resulting in widespread flooding across the Thames basin. We applied high-frequency (15 minute resolution) water quality monitoring across ten contrasting subcatchments (including rural, urban and mixed land-use catchments), seeking to classify the disparity in water quality conditions both within- and between events. Rural catchments increasingly behave like "urban" catchments as soils wet up and become increasingly responsive to subsequent events, however water quality response during the winter months remains limited. By contrast, increasingly urban catchments yield greater contaminant loads during events, and pre-event baseline chemistry highlights a resupply source in dense urban catchments. Wastewater treatment plants were shown to dominate baseline chemistry during low-flow events but also yield a considerable impact on stormwater outputs during peak-flow events, as hydraulic push results in the outflow of untreated solid wastes into the river system. Results are discussed in the context of water quality policy; urban growth scenarios and BMP for stormwater runoff in contrasting landscapes.

  20. Fluvial sediment transport in a glacier-fed high-mountain river (Riffler Bach, Austrian Alps)

    Science.gov (United States)

    Morche, David; Weber, Martin; Faust, Matthias; Schuchardt, Anne; Baewert, Henning

    2017-04-01

    High-alpine environments are strongly affected by glacier retreat since the Little Ice Age (LIA). Due to ongoing climate change the hydrology of proglacial rivers is also influenced. It is expected that the growing proportions of snow melt and rainfall events will change runoff characteristics of proglacial rivers. Additionally, the importance of paraglacial sediment sources in recently deglaciating glacier forefields is increasing, while the role of glacial erosion is declining. Thus complex environmental conditions leading to a complex pattern of fluvial sediment transport in partly glaciated catchments of the European Alps. Under the umbrella of the joint PROSA-project the fluvial sediment transport of the river Riffler Bach (Kaunertal, Tyrol, Austria) was studied in 3 consecutive ablation seasons in order to quantify sediment yields. In June 2012 a probe for water level and an automatic water sampler (AWS) were installed at the outlet of the catchment (20km2). In order to calculate annual stage-discharge-relations by the rating-curve approach, discharge (Q) was repeatedly measured with current meters and by salt dilution. Concurrent to the discharge measurements bed load was collected using a portable Helley-Smith sampler. Bed load samples were weighted and sieved in the laboratory to gain annual bed load rating curves and grain size distributions. In total 564 (2012: 154, 2013: 209, 2014: 201) water samples were collected and subsequently filtered to quantify suspended sediment concentrations (SSC). Q-SSC-relations were calculated for single flood events due to the high variability of suspended sediment transport. The results show a high inter- and intra-annual variability of solid fluvial sediment transport, which can be explained by the characteristics of suspended sediment transport. Only 13 of 22 event-based Q-SSC-relations show causal dependency. In 2012, during a period with multiple pluvial-induced peak discharges most sediment was transported. On the

  1. Snow avalanche activity in the High Tatras Mountains: new data achieved by means of dendrogeomorphic methods

    Science.gov (United States)

    Tichavsky, R.

    2016-12-01

    The High Tatras Mountains are permanently affected by the occurrence of hazardous geomorphic processes. Snow avalanches represent a common hazard that threatens the infrastructure and humans living and visiting the mountains. So far, the spatio-temporal reconstruction of snow avalanche histories was based only on existing archival records, orthophoto interpretation and lichenometric dating in the High Tatras Mountains. Dendrogeomorphic methods allow for the intra-seasonal dating of scars on tree stems and branches and have been broadly used for the dating of snow avalanche events all over the world. We extracted the increment cores and cross sections from 189 individuals of Pinus mugo var. mugo growing on four tali in the Great Cold Valley and dated all the past scars that could correspond with the winter to early spring occurrence of snow avalanches. The dating was supported by the visual analysis of three orthophoto images from 2004, 2009 and 2014. In total, nineteen event years of snow avalanches (10 certain events, and 9 probable events) were identified since 1959. Historical archives provided evidence only for nine event years since 1987, and three of them were confirmed dendrogeomorphically. Geomorphic effect of recent snow avalanches identified by the spatial distribution of scarred trees in individual years corresponds with the extent of events visible from the orthophotos. We can confirm higher frequency of snow avalanche events since 1980s (17 out of 19 events) and significant increase during the last ten years. The future expected climatic changes associated with the changes in temperature and precipitation regime could significantly influence on the frequency of snow avalanches. Therefore, our results can become the starting line for more extensive dendrogeomorphic survey in the High Tatras Mountains in order to create a catalogue of all natural hazards for the future prediction and modelling of these phenomena in context of environmental changes.

  2. A High-resolution Precipitation 2-step mapping Procedure (HiP2P) : Development and application to a tropical mountainous area

    NARCIS (Netherlands)

    Hunink, J. E.; Immerzeel, W. W.|info:eu-repo/dai/nl/290472113; Droogers, P.

    Understanding the spatial and temporal variability of precipitation in tropical high mountain areas remains a key challenge. Point measurements are often not sufficient to capture the strong spatial variability particularly in mountain regions. Satellite remote sensing allows capturing the spatial

  3. Health at the Sub-catchment Scale: Typhoid and Its Environmental Determinants in Central Division, Fiji.

    Science.gov (United States)

    Jenkins, Aaron Peter; Jupiter, Stacy; Mueller, Ute; Jenney, Adam; Vosaki, Gandercillar; Rosa, Varanisese; Naucukidi, Alanieta; Mulholland, Kim; Strugnell, Richard; Kama, Mike; Horwitz, Pierre

    2016-12-01

    The impact of environmental change on transmission patterns of waterborne enteric diseases is a major public health concern. This study concerns the burden and spatial nature of enteric fever, attributable to Salmonella Typhi infection in the Central Division, Republic of Fiji at a sub-catchment scale over 30-months (2013-2015). Quantitative spatial analysis suggested relationships between environmental conditions of sub-catchments and incidence and recurrence of typhoid fever. Average incidence per inhabited sub-catchment for the Central Division was high at 205.9/100,000, with cases recurring in each calendar year in 26% of sub-catchments. Although the numbers of cases were highest within dense, urban coastal sub-catchments, the incidence was highest in low-density mountainous rural areas. Significant environmental determinants at this scale suggest increased risk of exposure where sediment yields increase following runoff. The study suggests that populations living on large systems that broaden into meandering mid-reaches and floodplains with alluvial deposition are at a greater risk compared to small populations living near small, erosional, high-energy headwaters and small streams unconnected to large hydrological networks. This study suggests that anthropogenic alteration of land cover and hydrology (particularly via fragmentation of riparian forest and connectivity between road and river networks) facilitates increased transmission of typhoid fever and that environmental transmission of typhoid fever is important in Fiji.

  4. Erosion dynamics modelling in a coupled catchment-fan system with constant external forcing

    OpenAIRE

    Pepin, E.; Carretier, Sébastien; Hérail, Gérard

    2010-01-01

    Recent alluvial fan models have suggested that deep alluvial fan entrenchment could occur without any change in sediment and water influx. Moreover, other studies have shown that the evolution of a fan could strongly depend on feedback between the fan and the mountain catchment. We evaluate if natural entrenchment still occurs in a coupled catchment-fan system, and we evaluate its possible impact on the evolution of mountain erosion. We use a landscape evolution model where the mountain corre...

  5. Application of electrical and electromagnetic methods to study sedimentary covers in high mountain areas

    Science.gov (United States)

    Tomecka-Suchoń, Sylwia; Żogała, Bogdan; Gołębiowski, Tomisław; Dzik, Grażyna; Dzik, Tomasz; Jochymczyk, Krzysztof

    2017-08-01

    The results of geophysical studies conducted with selected electrical and electromagnetic methods in the Kondratowa Valley in the Tatra Mountains (the Carpathian Mountains, Poland) are presented in the article. The surveys were performed with the following methods: electrical resistivity tomography (ERT), georadar (GPR) and conductivity meter (CM). The objective of the noninvasive geophysical measurements was to determine the thickness of the Quaternary postglacial sediments that fill the bottom of the valley and to designate the accumulation of boulders deposited on Quaternary sediments. The results of ERT surveys conducted along the axis of the valley allowed to determine the changeability of the thickness of the postglacial sediments and allowed to designate a few areas of occurrence of boulders. The ERT, GPR and CM surveys conducted across the valley allowed to designate with high accuracy the thickness of the accumulation of boulders sliding down the valley bottom from the couloirs surrounding the valley.

  6. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain)

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Abstract Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988–1990 and 2009–2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:25878552

  7. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain).

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988-1990 and 2009-2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.

  8. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain

    Directory of Open Access Journals (Sweden)

    Antonio Jesús Pérez-Luque

    2015-02-01

    Full Text Available Sierra Nevada mountain range (southern Spain hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988–1990 and 2009–2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV, a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.

  9. Seasonal Patterns of Dry Deposition at a High-Elevation Site in the Colorado Rocky Mountains

    Science.gov (United States)

    Oldani, Kaley M.; Mladenov, Natalie; Williams, Mark W.; Campbell, Cari M.; Lipson, David A.

    2017-10-01

    In the Colorado Rocky Mountains, high-elevation barren soils are deficient in carbon (C) and phosphorus (P) and enriched in nitrogen (N). The seasonal variability of dry deposition and its contributions to alpine elemental budgets is critical to understanding how dry deposition influences biogeochemical cycling in high-elevation environments. In this 2 year study, we evaluated dry and wet deposition inputs to the Niwot Ridge Long Term Ecological Research (NWT LTER) site in the Colorado Rocky Mountains. The total organic C flux in wet + dry (including soluble and particulate C) deposition was >30 kg C ha-1 yr-1 and represents a substantial input for this C-limited environment. Our side-by-side comparison of dry deposition collectors with and without marble insert indicated that the insert improved retention of dry deposition by 28%. Annual average dry deposition fluxes of water-soluble organic carbon (4.25 kg C ha-1 yr-1) and other water-soluble constituents, including ammonium (0.16 kg NH4+ha-1 yr-1), nitrate (1.99 kg NO3- ha-1 yr-1), phosphate (0.08 kg PO43- ha-1 yr-1), and sulfate (1.20 kg SO42- ha-1 yr-1), were comparable to those in wet deposition, with highest values measured in the summer. Backward trajectory analyses implicate air masses passing through the arid west and Four Corners, USA, as dominant source areas for dry deposition, especially in spring months. Synchronous temporal patterns of deposition observed at the NWT LTER site and a distant Rocky Mountain National Park Clean Air Status and Trends Network site indicate that seasonal dry deposition patterns are regional phenomena with important implications for the larger Rocky Mountain region.

  10. Depths to Ice-cemented Soils in High-elevation Quartermain Mountains, Dry Valleys, Antarctica, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set is comprised of four surveyed valleys focusing on the depth to ground ice in the high-elevation Quartermain Mountains in the Beacon Valley area:...

  11. Detailed and Highly Accurate 3d Models of High Mountain Areas by the Macs-Himalaya Aerial Camera Platform

    Science.gov (United States)

    Brauchle, J.; Hein, D.; Berger, R.

    2015-04-01

    Remote sensing in areas with extreme altitude differences is particularly challenging. In high mountain areas specifically, steep slopes result in reduced ground pixel resolution and degraded quality in the DEM. Exceptionally high brightness differences can in part no longer be imaged by the sensors. Nevertheless, detailed information about mountainous regions is highly relevant: time and again glacier lake outburst floods (GLOFs) and debris avalanches claim dozens of victims. Glaciers are sensitive to climate change and must be carefully monitored. Very detailed and accurate 3D maps provide a basic tool for the analysis of natural hazards and the monitoring of glacier surfaces in high mountain areas. There is a gap here, because the desired accuracies are often not achieved. It is for this reason that the DLR Institute of Optical Sensor Systems has developed a new aerial camera, the MACS-Himalaya. The measuring unit comprises four camera modules with an overall aperture angle of 116° perpendicular to the direction of flight. A High Dynamic Range (HDR) mode was introduced so that within a scene, bright areas such as sun-flooded snow and dark areas such as shaded stone can be imaged. In 2014, a measuring survey was performed on the Nepalese side of the Himalayas. The remote sensing system was carried by a Stemme S10 motor glider. Amongst other targets, the Seti Valley, Kali-Gandaki Valley and the Mt. Everest/Khumbu Region were imaged at heights up to 9,200 m. Products such as dense point clouds, DSMs and true orthomosaics with a ground pixel resolution of up to 15 cm were produced. Special challenges and gaps in the investigation of high mountain areas, approaches for resolution of these problems, the camera system and the state of evaluation are presented with examples.

  12. Evaluation of the extent of contamination caused by historical mining in catchments of central Colorado

    Science.gov (United States)

    Church, Stan E.; Fey, David L.; Wanty, Richard B.; Schmidt, Travis S.; Klein, T.L.; Rockwell, Barnaby W.; San Juan, Carma A.

    2010-01-01

    The U.S. Geological Survey conducted an assessment of stream water and sediment quality in central Colorado, an area of about 54,000 km2. The study area is focused on small tributary catchments in the Rocky Mountains. The Colorado Mineral belt, a northeast-trending mineralized zone that experienced base- and precious-metal mining at the beginning of the late 1800s and early 1900s, cuts diagonally across the geologic trend in the study area. The goal of this study was to compare water and sediment quality in background catchments with those which have been mined. Water and sediment data from 200 catchments, and data from macroinvertebrates from more than 100 catchments, provided ample data for evaluation of the effects of mining on water and sediment quality. Focused sampling was conducted during low-flow conditions in the summers of 2004-2007. Samples were collected from catchments that (1) were underlain largely by a single lithologic unit, (2) contained hydrothermally altered rock and had been prospected, and (3) contained historical mines. Geochemical data determined from catchments that did not contain hydrothermal alteration or historical mines met water-quality criteria and recommended sediment-quality guidelines and showed small variations in base-metal concentrations. Hydrothermal alteration and mineralization typically are associated with igneous rocks that have intruded older bedrock. Base-metal concentrations were elevated in sediment from catchments underlain by hydrothermally altered rock. Catchments affected by historical mining contained highly elevated base-metal concentrations. Classification of catchments on the basis of mineral deposit types proved to be an efficient and accurate method for discriminating catchments that had degraded water and sediment quality. Only about 4.5 percent of the study area has been affected by historical mining, whereas a larger portion of the study area is underlain by hydrothermally altered rock. Weathering of QSP

  13. Long-term effects of high nitrogen loads on cation and carbon riverine export in agricultural catchments.

    Science.gov (United States)

    Aquilina, Luc; Poszwa, Anne; Walter, Christian; Vergnaud, Virginie; Pierson-Wickmann, Anne-Catherine; Ruiz, Laurent

    2012-09-04

    The intensification of agriculture in recent decades has resulted in extremely high nitrogen inputs to ecosystems. One effect has been H(+) release through NH(4)(+) oxidation in soils, which increases rock weathering and leads to acidification processes such as base-cation leaching from the soil exchange complex. This study investigated the evolution of cation concentrations over the past 50 years in rivers from the Armorican crystalline shield (Brittany, western France). On a regional scale, acidification has resulted in increased base-cation riverine exports (Ca(2+), Mg(2+), Na(+), K(+)) correlated with the increased NO(3)(-) concentration. The estimated cation increase is 0.7 mmol(+)/L for Ca(2+) + Mg(2+) and 0.85 mmol(+)/L for total cations. According to mass balance, cation loss represents >30% of the base-cation exchange capacity of soils. Long-term acidification thus contributes to a decline in soil productivity. Estimates of the total organic nitrogen annually produced worldwide indicate that acidification may also constitute an additional carbon source in crystalline catchments if compensated by liming practices.

  14. Assessment of vulnerability in karst aquifers using a quantitative integrated numerical model: catchment characterization and high resolution monitoring - Application to semi-arid regions- Lebanon.

    Science.gov (United States)

    Doummar, Joanna; Aoun, Michel; Andari, Fouad

    2016-04-01

    Karst aquifers are highly heterogeneous and characterized by a duality of recharge (concentrated; fast versus diffuse; slow) and a duality of flow which directly influences groundwater flow and spring responses. Given this heterogeneity in flow and infiltration, karst aquifers do not always obey standard hydraulic laws. Therefore the assessment of their vulnerability reveals to be challenging. Studies have shown that vulnerability of aquifers is highly governed by recharge to groundwater. On the other hand specific parameters appear to play a major role in the spatial and temporal distribution of infiltration on a karst system, thus greatly influencing the discharge rates observed at a karst spring, and consequently the vulnerability of a spring. This heterogeneity can only be depicted using an integrated numerical model to quantify recharge spatially and assess the spatial and temporal vulnerability of a catchment for contamination. In the framework of a three-year PEER NSF/USAID funded project, the vulnerability of a karst catchment in Lebanon is assessed quantitatively using a numerical approach. The aim of the project is also to refine actual evapotranspiration rates and spatial recharge distribution in a semi arid environment. For this purpose, a monitoring network was installed since July 2014 on two different pilot karst catchment (drained by Qachqouch Spring and Assal Spring) to collect high resolution data to be used in an integrated catchment numerical model with MIKE SHE, DHI including climate, unsaturated zone, and saturated zone. Catchment characterization essential for the model included geological mapping and karst features (e.g., dolines) survey as they contribute to fast flow. Tracer experiments were performed under different flow conditions (snow melt and low flow) to delineate the catchment area, reveal groundwater velocities and response to snowmelt events. An assessment of spring response after precipitation events allowed the estimation of the

  15. Mountain birch – potentially large source of sesquiterpenes into high latitude atmosphere

    Directory of Open Access Journals (Sweden)

    A. Arneth

    2009-11-01

    Full Text Available Emissions of volatile organic compounds (VOCs from mountain birches were measured in Abisko, northern Sweden. Mountain birches make up the majority of the tree biomass in Scandinavian high latitudes, a region subject to significant climate warming. The measurements were carried out in two growing seasons. The emissions of four branches, each from a different individual tree, were measured in June–August 2006 and one of them again in July 2007. The measurements were conducted using a dynamic flow through chamber covered with Teflon film. The studied mountain birches were found to emit substantial amounts of linalool, monoterpenes and sesquiterpenes. The monoterpene emission was dominated by sabinene. The magnitude and composition of the sesquiterpene emission changed dramatically between the years. For example, the average α-farnesene emission potential in 2006 was almost 2600 ng gdw−1 h−1 (3.5 pmol gdw−1 s−1 while in 2007 α-farnesene was not detected at all. Also the emissions of other sesquiterpenes decreased in 2007 to a fraction of that in 2006. One possible explanation for the change in emissions is the herbivory damage that occurred in the area in 2004. Herbivory is known to enhance the emissions of sesquiterpenes, especially those of α-farnesene, and the effect may last for several years.

  16. Nitrogen cycling responses to mountain pine beetle disturbance in a high elevation whitebark pine ecosystem

    Science.gov (United States)

    Keville, Megan P.; Reed, Sasha C.; Cleveland, Cory C.

    2013-01-01

    Ecological disturbances can significantly affect biogeochemical cycles in terrestrial ecosystems, but the biogeochemical consequences of the extensive mountain pine beetle outbreak in high elevation whitebark pine (WbP) (Pinus albicaulis) ecosystems of western North America have not been previously investigated. Mountain pine beetle attack has driven widespread WbP mortality, which could drive shifts in both the pools and fluxes of nitrogen (N) within these ecosystems. Because N availability can limit forest regrowth, understanding how beetle-induced mortality affects N cycling in WbP stands may be critical to understanding the trajectory of ecosystem recovery. Thus, we measured above- and belowground N pools and fluxes for trees representing three different times since beetle attack, including unattacked trees. Litterfall N inputs were more than ten times higher under recently attacked trees compared to unattacked trees. Soil inorganic N concentrations also increased following beetle attack, potentially driven by a more than two-fold increase in ammonium (NH4+) concentrations in the surface soil organic horizon. However, there were no significant differences in mineral soil inorganic N or soil microbial biomass N concentrations between attacked and unattacked trees, implying that short-term changes in N cycling in response to the initial stages of WbP attack were restricted to the organic horizon. Our results suggest that while mountain pine beetle attack drives a pulse of N from the canopy to the forest floor, changes in litterfall quality and quantity do not have profound effects on soil biogeochemical cycling, at least in the short-term. However, continuous observation of these important ecosystems will be crucial to determining the long-term biogeochemical effects of mountain pine beetle outbreaks.

  17. Contribution of high resolution remote sensing data to the modeling of the snow cover the in Atlas Mountains

    Science.gov (United States)

    Baba, Wassim; Gascoin, Simon; Hanich, Lahoucine; Kinnard, Christophe

    2017-04-01

    Snow melt from the Atlas Mountains watersheds represent an important water resource for the semi-arid, cultivated, lowlands. Due to the high incoming solar radiation and low precipitation, the spatial-temporal variability of the snowpack is expected to be strongly influenced by the topography. We explore this hypothesis using a distributed energy balance snow model (SnowModel) in the experimental watershed of the Rheraya River in Morocco (225 km2). The digital elevation model (DEM) in SnowModel is used for the computation of the gridded meteorological forcing from the automatic weather stations data. We acquired three Pléiades stereo pairs in to produce an accurate, high resolution DEM of the Rheraya watershed at 4 m posting. Then, the DEM was resampled to different spatial resolutions (8 m, 30 m, 90 m, 250 m and 500 m) to simulate the snowpack evolution over 2008-2009 snow season. As validation data we used a time series of 15 maps of the snow cover area (SCA) from Formosat-2 imagery over the same snow season in the upper Rheraya watershed. These maps have a resolution of 8 m, which enables to capture small-scale variability in the snow cover. We found that the simulations at 90 m, 30 m and 8 m yield similar results at the catchment scale, with significant differences in areas of very steep topography only. From February to April, an overall good agreement was observed between the simulated SCA and the Formosat-2 SCA at 8 m and 90 m. Before the melting season, true positive (TP) column of confusion matrix is close to 1, but it drops to 0.6 during the melting season. Heidke Skill Score is higher than 0.7 for the most of the validation dates and averages 0.8. On the contrary, 500 m simulation underestimates the SCA throughout the snow season and the TP score is always inferior to the one obtained at 8 m and 90 m. We further analyzed the effect of topography by comparing the distribution of meteorological and snowpack variables along north-south and east

  18. Value of different precipitation data for flood prediction in an alpine catchment: A Bayesian approach

    Science.gov (United States)

    Sikorska, A. E.; Seibert, J.

    2018-01-01

    Flooding induced by heavy precipitation is one of the most severe natural hazards in alpine catchments. To accurately predict such events, accurate and representative precipitation data are required. Estimating catchment precipitation is, however, difficult due to its high spatial, and, in the mountains, elevation-dependent variability. These inaccuracies, together with runoff model limitations, translate into uncertainty in runoff estimates. Thus, in this study, we investigate the value of three precipitation datasets, commonly used in hydrological studies, i.e., station network precipitation (SNP), interpolated grid precipitation (IGP) and radar-based precipitation (RBP), for flood predictions in an alpine catchment. To quantify their effects on runoff simulations, we perform a Bayesian uncertainty analysis with an improved description of model systematic errors. By using periods of different lengths for model calibration, we explore the information content of these three datasets for runoff predictions. Our results from an alpine catchment showed that using SNP resulted in the largest predictive uncertainty and the lowest model performance evaluated by the Nash-Sutcliffe efficiency. This performance improved from 0.674 to 0.774 with IGP, and to 0.829 with RBP. The latter two datasets were also much more informative than SNP, as half as many calibration data points were required to obtain a good model performance. Thus, our results show that the various types of precipitation data differ in their value for flood predictions in an alpine catchment and indicate RBP as the most useful dataset.

  19. High frequency turbidity as a proxy for total phosphorus: application in a mixed land use catchment in Sweden

    Science.gov (United States)

    Lannergård, Emma; Ledesma, José L. J.; Fölster, Jens; Futter, Martyn N.

    2017-04-01

    Surface water eutrophication resulting from excessive phosphorus (P) input is one of the most challenging water issues of today. Total phosphorus (TP) concentrations have high temporal variability, which makes the parameter hard to monitor adequately. We explored the possibility of using high frequency turbidity as a proxy for TP in Sävjaån, a stream in a mixed land use catchment in Sweden. An in situ sensor (YSI 600OMS VS) monitoring turbidity every 10th minute, was situated close to the outlet of Sävjaån during 2014 and 2015. In situ and grab sample turbidity measurements were highly correlated (linear regression, r2=0.90). The maximum turbidity concentration measured by the sensor was at most 13 times higher than the highest concentration from the grab samples. The average turbidity concentration from the two methods was close to similar, as well as the Ecological Quality Ratios (EQR) calculated from the two data sets. The correlation between TP and high frequency turbidity was very high (r2=0.79) and between TSS and turbidity high (r2=0.67). When comparing load estimations from the high frequency data with monthly grab sampling and linear interpolation, the high frequency load was 7 % smaller in 2014 and 17 % larger in 2015. In 2014 the monthly grab sampling caught peaks in TP concentration, which with linear interpolation affected the nearby months and furthermore the yearly load. However, in 2015 peaks in concentration were overlooked when using grab sampling, which gave a larger yearly load when using the high frequency data. Season and flow intensity may affect the relationship between turbidity and TP, however this could not be statistically proven in this study. The proxy relationship could also result in uncertainties tied to unexplained diurnal variations of turbidity, proportion particulate bound P or hysteresis. Uncertainties arising from the use of sensors (e.g. sensor calibration and spatial representation) must as well be recognized. To

  20. Production of high-resolution digital terrain models in mountain regions to support risk assessment

    Directory of Open Access Journals (Sweden)

    Gianfranco Forlani

    2015-07-01

    Full Text Available Demand for high-accuracy digital terrain models (DTMs in the Alpine region has been steadily increasing in recent years in valleys as well as high mountains. In the former, the determination of the geo-mechanical parameters of rock masses is the main objective; global warming, which causes the retreat of glaciers and the reduction of permafrost, is the main drive of the latter. The consequence is the instability of rock masses in high mountains: new cost-effective monitoring techniques are required to deal with the peculiar characteristics of such environment, delivering results at short notice. After discussing the design and execution of photogrammetric surveys in such areas, with particular reference to block orientation and block control, the paper describes the production of DTMs of rock faces and glacier fronts with light instrumentation and data acquisition techniques, allowing highly automated data processing. To this aim, the PhotoGPS technique and structure from motion algorithms are used to speed up the orientation process, while dense matching area-based correlation techniques are used to generate the DTMs.

  1. Palaeoethnobotanical Data from the High Mountainous Early Bronze Age Settlement of Tsaghkasar-1 (Mt. Aragats, Armenia

    Directory of Open Access Journals (Sweden)

    Roman Hovsepyan

    2011-09-01

    Full Text Available Palaeoethnobotanical investigations suggest that at least part of the Early Bronze Age population of Tsaghkasar was settled and practiced agriculture in the high mountainous zone. People there appear to have cultivated hexa‐ and tetraploid wheats (probably bread wheat and emmer and barley (possibly hulled. Bronze Age agriculture in the Southern Caucasus differs from earlier and later period when cultivation of pulses, oil‐producing plants, and other plants was common. This emphasis on the cultivation and use of certain cereal grains at Early Bronze sites such as Tsaghkasar can tentatively be added to a constellation of practices associated with the Kura‐Araxes culture in the South Caucasus.

  2. Graphical possibilities in determining the vertical deflections in high-mountain regions

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    Sedlák Vladimír

    2000-03-01

    Full Text Available The paper presents a possibility of determining the topographical deflections of the vertical in a high-mountain region by means of using a simple and rapid graphical method. During five minutes it is possible to determine the topographical deflections of the vertical with the accuracy of ±(1½ using the explicit mathematical equations and a simple topographical map. The mathematical correction for very asymmetrical peaks, by-valleys and irregular slopes are given. No astronomical and geodetic observations or digital height models are necessary.

  3. Corneal Opacity in a Participant of a 161-km Mountain Bike Race at High Altitude.

    Science.gov (United States)

    Khodaee, Morteza; Torres, David R

    2016-06-01

    Visual dysfunction is a relatively uncommon complaint among athletes during ultraendurance races. The pathophysiology of most of these cases is unknown. Corneal opacity has been speculated as the etiology for most of reported cases. We are presenting a case of a 56-year-old man with a partial unilateral corneal opacity and edema at kilometer 150 of a 161-km mountain bike race in high altitude. He was not able to finish the race (12-hour cutoff) because of his visual symptoms. He completely recovered in 3 days with no sequelae. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  4. Using high-performance mathematical modelling tools to predict erosion and sediment fluxes in peri-urban catchments

    Science.gov (United States)

    Pereira, André; Conde, Daniel; Ferreira, Carla S. S.; Walsh, Rory; Ferreira, Rui M. L.

    2017-04-01

    the standard observed in available models. The assembled parallel model is expected to achieve faster than real-time simulations for high resolutions (from meters to sub-meter) in large scaled problems (from cities to watersheds), effectively bridging the gap between detailed and timely simulation results. The model was validated in Ribeira dos Covões watershed, a peri-urban catchment (6 km2) in the outskirts of the Coimbra city, in central Portugal. Urban land-use has increased from 6% in 1958 to 40% in 2012. The watershed geology comprises a limestone sandstone areas. The soils are generally deep and hydrophobic for part of the year, particularly in the forested areas. Previous research used a sediment fingerprinting approach to establish the relative importance of sediment inputs from different urban areas (Ferreira et al., submitted). The study showed that most of the current catchment erosion is derived from construction sites in the sandstone areas. This was supported by the higher measured discharges and suspended sediment concentrations in storm events from downslope tributaries. The results of the model are well correlated with field surveys. However, the sever disruption of the channel network by human usage, namely land partition, poses specific modelling challenges, causing the quantitative agreement to be poor. To tackle this problem, it is necessary to introduce as much detail as possible in the specification of the elevation model. Acknowledgements This research was partially supported by Portuguese and European funds, within programs COMPETE2020 and PORL-FEDER, through project PTDC/ECM-HID/6387/2014 granted by the National Foundation for Science and Technology (FCT). References Canelas, R.; Murillo, J. & Ferreira, R.M.L. (2013), Two-dimensional depth-averaged modelling of dam-break flows over mobile beds. Journal of Hydraulic Research, 51(4), 392-407. Conde, D.A.S.; Telhado, M.J.; Viana Baptista, M.A. & Ferreira, R. M. L. (2015) Severity and exposure

  5. Volumes of sediment stored in an Alpine catchment using geological, geomorphological and geophysical expertise: Peynin catchment (Queyras, Southern French Alps)

    Science.gov (United States)

    Carlier, Benoît; Carlier, Gabriel; Lissak, Candide; Gance, Julien; Malet, Jean-Philippe; Graff, Kevin; Viel, Vincent; Arnaud-Fassetta, Gilles; Fort, Monique; Bétard, François; Madelin, Malika

    2017-04-01

    The combination of predisposing factors (schist bedrock supplying abundant debris, high slope gradient and strong hillslope-channel connectivity), makes the Upper Guil catchment particularly prone to torrential hazards such as floods or debris flows. The occurrence of "Lombarde easterlies" episodes may generate intense rainfall over short time periods (320 mm in 8 days in June 1957). During such events, the observed damages are mainly related to the sediment transport (fine sediments and metric boulders) in the torrential streams, as in 1946 and 1957, and more recently in 2000, 2008 and 2010. In order to evaluate mountainous hazards in a Global Change context (i.e. climatic and socio-economic), the French funded ANR project SAMCO put the emphasis on the hydrogeomorphological functioning of the Upper Guil catchment. In this context, a sedimentary budget analysis at the Holocene timescale was elaborated for the active Peynin catchment (≈ 15 km2). The volumes of sediments stored on the slopes and in the channels are evaluated using geophysical and geomorphological investigations in order to establish the amount of material potentially mobilized during low frequency/high magnitude flood events. On the basis of intensive fieldwork and GIS mapping (geology and geomorphology), two models of sediment thickness are proposed. The first one, inspired by the work of Schrott et al. (2003), is based on the modelling of the supposed bedrock roof using polynomial functions and GIS modelling (high estimate). The second model is field based and results from a geological and geomorphological analysis of 46 topographic and geologic cross sections (low estimate). To reduce the error margins in sediment thickness estimates, three seismic refraction profiles made in summer 2014 have been interpreted and integrated to these models. The volumes of sediments stored in the Peynin catchment were respectively estimated to 0.423 km3 (high estimate) and 0.171 km3 (low estimate). This

  6. Spatiotemporal patterns of High Mountain Asia's snowmelt season identified with an automated snowmelt detection algorithm, 1987–2016

    Directory of Open Access Journals (Sweden)

    T. Smith

    2017-10-01

    Full Text Available High Mountain Asia (HMA – encompassing the Tibetan Plateau and surrounding mountain ranges – is the primary water source for much of Asia, serving more than a billion downstream users. Many catchments receive the majority of their yearly water budget in the form of snow, which is poorly monitored by sparse in situ weather networks. Both the timing and volume of snowmelt play critical roles in downstream water provision, as many applications – such as agriculture, drinking-water generation, and hydropower – rely on consistent and predictable snowmelt runoff. Here, we examine passive microwave data across HMA with five sensors (SSMI, SSMIS, AMSR-E, AMSR2, and GPM from 1987 to 2016 to track the timing of the snowmelt season – defined here as the time between maximum passive microwave signal separation and snow clearance. We validated our method against climate model surface temperatures, optical remote-sensing snow-cover data, and a manual control dataset (n = 2100, 3 variables at 25 locations over 28 years; our algorithm is generally accurate within 3–5 days. Using the algorithm-generated snowmelt dates, we examine the spatiotemporal patterns of the snowmelt season across HMA. The climatically short (29-year time series, along with complex interannual snowfall variations, makes determining trends in snowmelt dates at a single point difficult. We instead identify trends in snowmelt timing by using hierarchical clustering of the passive microwave data to determine trends in self-similar regions. We make the following four key observations. (1 The end of the snowmelt season is trending almost universally earlier in HMA (negative trends. Changes in the end of the snowmelt season are generally between 2 and 8 days decade−1 over the 29-year study period (5–25 days total. The length of the snowmelt season is thus shrinking in many, though not all, regions of HMA. Some areas exhibit later peak signal separation (positive

  7. Spatiotemporal patterns of High Mountain Asia's snowmelt season identified with an automated snowmelt detection algorithm, 1987-2016

    Science.gov (United States)

    Smith, Taylor; Bookhagen, Bodo; Rheinwalt, Aljoscha

    2017-10-01

    High Mountain Asia (HMA) - encompassing the Tibetan Plateau and surrounding mountain ranges - is the primary water source for much of Asia, serving more than a billion downstream users. Many catchments receive the majority of their yearly water budget in the form of snow, which is poorly monitored by sparse in situ weather networks. Both the timing and volume of snowmelt play critical roles in downstream water provision, as many applications - such as agriculture, drinking-water generation, and hydropower - rely on consistent and predictable snowmelt runoff. Here, we examine passive microwave data across HMA with five sensors (SSMI, SSMIS, AMSR-E, AMSR2, and GPM) from 1987 to 2016 to track the timing of the snowmelt season - defined here as the time between maximum passive microwave signal separation and snow clearance. We validated our method against climate model surface temperatures, optical remote-sensing snow-cover data, and a manual control dataset (n = 2100, 3 variables at 25 locations over 28 years); our algorithm is generally accurate within 3-5 days. Using the algorithm-generated snowmelt dates, we examine the spatiotemporal patterns of the snowmelt season across HMA. The climatically short (29-year) time series, along with complex interannual snowfall variations, makes determining trends in snowmelt dates at a single point difficult. We instead identify trends in snowmelt timing by using hierarchical clustering of the passive microwave data to determine trends in self-similar regions. We make the following four key observations. (1) The end of the snowmelt season is trending almost universally earlier in HMA (negative trends). Changes in the end of the snowmelt season are generally between 2 and 8 days decade-1 over the 29-year study period (5-25 days total). The length of the snowmelt season is thus shrinking in many, though not all, regions of HMA. Some areas exhibit later peak signal separation (positive trends), but with generally smaller magnitudes

  8. Sediment tracing, mixing and budgets in debris flow catchments: a cosmogenic nuclide perspective

    Science.gov (United States)

    Kober, Florian; Hippe, Kristina; Salcher, Bernhard; Grischott, Reto; Christl, Markus; Hählen, Nils

    2013-04-01

    Mountain catchments are at the start of the source-to-sink cycle in erosional and sedimentary environments. These catchments are sensitive to climate, geomorphic inheritance and human perturbation and are commonly dominated by episodic mass-wasting processes (landslides, debris flows). Quantifying the production and evacuation of sediment from such catchments (i.e. their erosion rates) is difficult and highly dependent on the spatial and temporal scales investigated and the methods/techniques applied. Crucial questions are where and when the sediment is mobilized and discharged, and where and how the quantitative erosion measurement is taken in time and space. We have investigated such issues in the Haslital Aare of Central Switzerland, from a sediment yield and a cosmogenic nuclide perspective. Localized mobilization of sediment as debris flows due to rockfall, heavy rainfall and permafrost thawing has been quantified volumetrically and in terms of cosmogenic nuclide (10Be) concentrations. Sediment sources and reservoirs (talus slope deposits, glacial debris, hillslopes, debris flow fans) are investigated at the source site, at the tributary - trunk stream junction (debris-flow subcatchment scale, ~4 km2) and at the outlet of the catchment (~70 km2). These measurements indicate that the sediment is not as thoroughly mixed at subcatchment and catchment scale as required by the concept of cosmogenic nuclide. However, a balancing effect (potentially back to natural background levels) of localized signals is observed at variable temporal and spatial distances of the episodic event. Detected sediment volumes mobilized during debris-flow events are larger than those calculated from cosmogenic nuclide derived denudation rates. This is largely due to lateral and vertical sediment entrainment in debris flow channels for which the cosmogenic nuclide method is little sensitive. The incorporation of non-steady produced sediment (residing in shielded fan deposits) can yield

  9. Effect of temperature on the progamic phase in high-mountain plants.

    Science.gov (United States)

    Steinacher, G; Wagner, J

    2012-03-01

    Progamic processes are particularly temperature-sensitive and, in lowland plants, are usually drastically reduced below 10 °C and above 30 °C. Little is known about how effectively sexual processes of mountain plants function under the large temperature fluctuations at higher altitudes. The present study examines duration and thermal thresholds for progamic processes in six common plant species (Cerastium uniflorum, Gentianella germanica, Ranunculus alpestris, R. glacialis, Saxifraga bryoides, S. caesia) from different altitudinal zones in the European Alps. Whole plants were collected from natural sites shortly before anthesis and kept in a climate chamber until further processing. Flowers with receptive stigmas were hand-pollinated with allopollen and exposed to controlled temperatures between -2 and 40 °C. Pollen performance (adhesion to the stigma, germination, tube growth, fertilisation) was quantitatively analysed, using the aniline blue fluorescence method. Pollen adhesion was possible from -2 to 40 °C. Pollen germination and tube growth occurred from around 0 to 35 °C in most species. Fertilisation was observed from 5 to 30-32 °C (0-35 °C in G. germanica). The progamic phase was shortest in G. germanica (2 h at 30 °C, 12 h at 5 °C, 24 h at 0 °C), followed by R. glacialis (first fertilisation after 2 h at 30 °C, 18 h at 5 °C). In the remaining species, first fertilisation usually occurred after 4-6 h at 30 °C and after 24-30 h at 5 °C. Thus, mountain plants show remarkably flexible pollen performance over a wide temperature range and a short progamic phase, which may be essential for successful reproduction in the stochastic high-mountain climate. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

  10. A hotspot for cold crenarchaeota in the neuston of high mountain lakes.

    Science.gov (United States)

    Auguet, Jean-Christophe; Casamayor, Emilio O

    2008-04-01

    We have surveyed the first 1 m of 10 oligotrophic high mountain lakes in the Central Pyrenees (Spain) for both abundance and predominant phylotypes richness of the archaeaplankton assemblage, using CARD-FISH and 16S rRNA gene sequencing respectively. Archaea inhabiting the air-water surface microlayer (neuston) ranged between 3% and 37% of total 4,6-diamidino-2-phenylindole (DAPI) counts and were mainly Crenarchaeota of a new freshwater cluster distantly related to the Marine Group 1.1a. Conversely, most of the Archaea from the underlying waters (the remaining first 1 m integrated) were mainly Euryarchaeota of three distantly related branches ranging between 0.4% and 27% of total DAPI counts. Therefore, a consistent qualitative and quantitative spatial segregation was observed for the two main archaeal phyla between neuston and underlying waters at a regional scale. We also observed a consistent pattern along the lakes surveyed between lake area, lake depth and water residence time, and the archaeal enrichment in the neuston: the larger the lake the higher the proportion of archaea in the neuston as compared with abundances from the underlying waters (n = 10 lakes; R(2) > 0.80; P Crenarchaeota can be found naturally enriched. High mountain lakes offer great research opportunities to explore the ecology of one of the most enigmatic and far from being understood group of prokaryotes.

  11. Physical exercise through mountain hiking in high-risk suicide patients. A randomized crossover trial.

    Science.gov (United States)

    Sturm, J; Plöderl, M; Fartacek, C; Kralovec, K; Neunhäuserer, D; Niederseer, D; Hitzl, W; Niebauer, J; Schiepek, G; Fartacek, R

    2012-12-01

    The following crossover pilot study attempts to prove the effects of endurance training through mountain hiking in high-risk suicide patients. Participants (n = 20) having attempted suicide at least once and clinically diagnosed with hopelessness were randomly distributed among two groups. Group 1 (n = 10) began with a 9-week hiking phase followed by a 9-week control phase. Group 2 (n = 10) worked vice versa. Assessments included the Beck Hopelessness Scale (BHS), Beck Depression Inventory (BDI), Beck Scale of Suicide Ideation (BSI), and maximum physical endurance. Ten participants of Group 1 and seven participants of Group 2 completed the study. A comparison between conditions showed that, in the hiking phase, there was a significant decrease in hopelessness (P suicide ideation (P = 0.25, d = -0.29). However, within the hiking phase, there was a significant decrease in suicide ideation (P = 0.005, d = -0.79). The results suggest that a group experience of regular monitored mountain hiking, organized as an add-on therapy to usual care, is associated with an improvement of hopelessness, depression, and suicide ideation in patients suffering from high-level suicide risk. © 2012 John Wiley & Sons A/S.

  12. Satisfaction of mountain guides with high sun protection as a tool to prevent non-melanoma skin cancer.

    Science.gov (United States)

    Tizek, L; Krause, J; Biedermann, T; Zink, A

    2017-11-01

    Non-melanoma skin cancer (NMSC) is an occupational disease for outdoor workers in Germany since 2015. Sustainable prevention is demanded and sunscreen promoted as an effective tool. However, studies on the satisfaction of sunscreen users are rare. To evaluate the satisfaction of mountain guides using a high SPF sunscreen product as an appropriate prevention tool for mountain guides. Motivating mountain and ski guides in Germany to use very high protection sunscreen (SPF50+, Actinica Lotion) during a 4- to 8-h workday followed by the completion of a self-filled paper-based questionnaire about their experience and satisfaction with the product. Of 88 mountain and ski guides (61 men, 27 women) included in the study, 61.4% reported regular sunscreen use with the application of very high protection (SPF50+) in 18.6% of all cases. At the end of the workday, 78.6% found the product convenient and easy to include into their daily work and 79.3% felt sufficiently protected against the sun. Overall satisfaction with the use of high SPF products during work is high in mountain and ski guides and could be an effective tool in prevention campaigns. © 2017 European Academy of Dermatology and Venereology.

  13. Role of antecedent conditions on nitrogen and phosphorus mobilisation observed in a lowland arable catchment in eastern England: insights from high-frequency monitoring

    Science.gov (United States)

    Outram, Faye; Hiscock, Kevin; Dugdale, Stephen; Lovett, Andrew

    2015-04-01

    In order to reduce annual riverine loadings of nutrients which are responsible for degradation of ecosystems downstream and in near coastal areas, it is important to first understand the mobilisation and pathways responsible for transporting them from source to river and how these pathways vary in space and time. The Blackwater tributary of the River Wensum in Norfolk, England, has been equipped with a sensor network as part of the Demonstration Test Catchments project, which has the aim of reducing pollution from agriculture to river systems whilst maintaining food security by the trial of mitigation measures on working farms at the sub-catchment level. The River Wensum is a lowland chalk catchment with intensive arable agriculture and high occurrence of tile drainage on heavier soils. Three hydrological years of high-frequency data have been gathered in the Blackwater since October 2011, including rainfall, half hourly measurements of discharge and groundwater level coupled with hydrochemical parameters including nitrate, total phosphorus (TP) and total reactive phosphorus (TRP). In the three years of data collection, there were distinct departures from long-term rainfall averages as the winter of 2011-12 was extremely dry following a drought from the previous hydrological year, followed by a summer which was unseasonably wet, which continued into the following winter. The relationship between rainfall, storage and discharge was found to be complex, which in turn had an impact on the dominant controls transporting nutrients from the landscape to the river network. Thirty three storms occurred throughout the three year period which have been analysed in the context of the range of hydrometeorological conditions observed throughout the dataset. Discharge-concentration hysteretic responses of nitrogen, TP and TRP have been used alongside statistical analysis of storm characteristics including antecedent hydrological conditions. The nitrate storm response showed

  14. Mountain landscapes offer few opportunities for high-elevation tree species migration

    Science.gov (United States)

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2014-01-01

    Climate change is anticipated to alter plant species distributions. Regional context, notably the spatial complexity of climatic gradients, may influence species migration potential. While high-elevation species may benefit from steep climate gradients in mountain regions, their persistence may be threatened by limited suitable habitat as land area decreases with elevation. To untangle these apparently contradictory predictions for mountainous regions, we evaluated the climatic suitability of four coniferous forest tree species of the western United States based on species distribution modeling (SDM) and examined changes in climatically suitable areas under predicted climate change. We used forest structural information relating to tree species dominance, productivity, and demography from an extensive forest inventory system to assess the strength of inferences made with a SDM approach. We found that tree species dominance, productivity, and recruitment were highest where climatic suitability (i.e., probability of species occurrence under certain climate conditions) was high, supporting the use of predicted climatic suitability in examining species risk to climate change. By predicting changes in climatic suitability over the next century, we found that climatic suitability will likely decline, both in areas currently occupied by each tree species and in nearby unoccupied areas to which species might migrate in the future. These trends were most dramatic for high elevation species. Climatic changes predicted over the next century will dramatically reduce climatically suitable areas for high-elevation tree species while a lower elevation species, Pinus ponderosa, will be well positioned to shift upslope across the region. Reductions in suitable area for high-elevation species imply that even unlimited migration would be insufficient to offset predicted habitat loss, underscoring the vulnerability of these high-elevation species to climatic changes.

  15. Zonation of High Disaster Potential Communities for Remote Mountainous Areas in Southern Taiwan

    Science.gov (United States)

    Chen, Yie-Ruey; Tsai, Kuang-Jung; Chang, Chwen-Ming; Chen, Jing-Wen; Chiang, Jie-Lun; Lu, Yi-Ching; Tsai, Hui-Wen

    2017-04-01

    About three-quarters of Taiwan are covered by hillside areas. Most of the hillside regions in Taiwan are sedimentary and metamorphic rocks which are fragile and highly weathered. In recent years, human development coupled with the global impact of extreme weather, typhoons and heavy rains have caused the landslide disasters and leaded to human causalities and properties loss. The landslides also endanger the major public works and almost make the overall industrial economic development and transport path overshadowed by disasters. Therefore, this research assesses the exploration of landslide potential analysis and zonation of high disaster potential communities for remote mountainous areas in southern Taiwan. In this study, the time series of disaster records and land change of remote mountainous areas in southern Taiwan are collected using techniques of interpretation from satellite images corresponding to multi-year and multi-rainfall events. To quantify the slope hazards, we adopt statistical analysis model to analyze massive data of slope disasters and explore the variance, difference and trend of influence factors of hillside disaster; establish the disaster potential analysis model under the climate change and construct the threshold of disaster. Through analysis results of disaster potential assessment, the settlement distribution with high-risk hazard potential of study area is drawn with geographic information system. Results of image classification show that the values of coefficient of agreement for different time periods are at high level. Compared with the historical disaster records of research areas, the accuracy of predicted landslide potential is in reasonable confidence level. The spatial distribution of landslide depends on the interaction of rainfall patterns, slope and elevation of the research area. The results also show that the number and scale of secondary landslide sites are much larger than those of new landslide sites after rainfall

  16. Geodetic mass balance of key glaciers across High Mountain Asia: a multi-decadal survey

    Science.gov (United States)

    Maurer, J. M.; Schaefer, J. M.; Rupper, S.; Corley, A. D.

    2016-12-01

    Glaciers in High Mountain Asia (HMA) supply seasonal meltwater for large populations, yet field observations are scarce and glacier sensitivities are poorly understood. In order to link complex atmospheric driving factors with heterogeneous glacier responses, detailed remote sensing observations of past changes in ice volume are needed. Here we compile a spatially and temporally extensive satellite-based remote sensing record to quantify multi-decadal geodetic mass balance of large mountain glaciers across key regions in HMA, including the Pamir, Himachal Pradesh, Uttarakhand, Nepal, Sikkim, and Bhutan regions. By utilizing declassified spy satellite imagery from the 1970's, ASTER scenes spanning 2000-present, and the ALOS global digital surface model, a methodologically homogenous assessment of regional and individual glacier responses to climate change over several decades is obtained. Although gaps due to low radiometric contrast result in significant uncertainties, the consistent approach across the HMA provides a useful comparison of relative geodetic changes between climatically diverse regions. Various patterns of ice loss are observed, including dynamic retreat of clean-ice glaciers and downwasting of debris-covered glaciers. In particular, we highlight the pronounced thinning and retreat of glaciers undergoing calving into proglacial lakes, which has important implications regarding ongoing and future ice loss of HMA glaciers.

  17. River-groundwater connectivity and nutrient dynamics in a mesoscale catchment

    Science.gov (United States)

    Fleckenstein, Jan H.; Musolff, Andreas; Gilfedder, Benjamin; Frei, Sven; Wankmüller, Fabian; Trauth, Nico

    2017-04-01

    Diffuse solute exports from catchments are governed by many interrelated factors such as land use, climate, geological-/ hydrogeological setup and morphology. Those factors create spatial variations in solute concentrations and turnover rates in the subsurface as well as in the stream network. River-groundwater connectivity is a crucial control in this context: On the one hand groundwater is a main pathway for nitrate inputs to the stream. On the other hand, groundwater connectivity with the stream affects the magnitude of hyporheic exchange of stream water with the stream bed. We present results of a longitudinal sampling campaign along the Selke river, a 67 km long third-order stream in the Harz mountains in central Germany. Water quality at the catchment outlet is strongly impacted by agriculture with high concentrations of nitrate and a chemostatic nitrate export regime. However, the specific nitrate pathways to the stream are not fully understood as there is arable land distributed throughout the catchment. While the sparsely distributed arable land in the mountainous upper catchment receives much higher amounts of precipitation, the downstream alluvial plains are drier, but more intensively used. The three-day campaign was conducted in June 2016 under constant low flow conditions. Stream water samples were taken every 2 km along the main stem of the river and at its major tributaries. Samples were analyzed for field parameters, major cations and anions, N-O isotopes, nutrients and Radon-222 (Rn) concentrations. Additionally, at each sampling location, river discharge was manually measured using current meters. Groundwater influxes to each sampled river section were quantified from the Rn measurements using the code FINIFLUX, (Frei and Gilfedder 2015). Rn and ion concentrations showed an increase from the spring to the mouth, indicating a growing impact of groundwater flux to the river. However, increases in groundwater gains were not gradual. The strongest

  18. High Concentrations of Ozone Air Pollution on Mount Everest: Health Implications for Sherpa Communities and Mountaineers.

    Science.gov (United States)

    Semple, John L; Moore, G W Kent; Koutrakis, Petros; Wolfson, Jack M; Cristofanelli, Paolo; Bonasoni, Paolo

    2016-12-01

    Semple, John L., G.W. Kent Moore, Petros Koutrakis, Jack M. Wolfson, Paolo Cristofanelli, and Paolo Bonasoni. High concentrations of ozone air pollution on Mount Everest: health implications for Sherpa communities and mountaineers. High Alt Med Biol. 17:365-369, 2016.-Introduction: Populations in remote mountain regions are increasingly vulnerable to multiple climate mechanisms that influence levels of air pollution. Few studies have reported on climate-sensitive health outcomes unique to high altitude ecosystems. In this study, we report on the discovery of high-surface ozone concentrations and the potential impact on health outcomes on Mount Everest and the high Himalaya. Surface ozone measurements were collected during ascending transects in the Mount Everest region of Nepal with passive nitrite-coated Ogawa filter samplers to obtain 8-hour personal exposures (2860-5364 m asl). In addition, the Nepal Climate Observatory-Pyramid, a GAW-WMO Global Station sited in the Khumbu Valley (5079 m asl), collected ozone mixing ratios with photometric gas analyzer. Surface ozone measurements increased with altitude with concentrations that exceed 100 ppb (8-hour exposure). Highest values were during the spring season and the result of diverse contributions: hemispheric background values, the descent of ozone-rich stratospheric air, and the transport of tropospheric pollutants occurring at different spatial scales. Multiple climate factors, including descending stratospheric ozone and imported anthropogenic air masses from the Indo-Gangetic Plain, contribute to ambient ozone exposure levels in the vicinity of Mount Everest that are similar to if not higher than those reported in industrialized cities.

  19. Usefulness of four hydrological models in simulating high-resolution discharge dynamics of a catchment adjacent to a road

    Science.gov (United States)

    Kalantari, Z.; Jansson, P.-E.; Stolte, J.; Folkeson, L.; French, H. K.; Sassner, M.

    2012-04-01

    Four hydrological models (LISEM, MIKE SHE, CoupModel and HBV) were compared with respect to their capability to predict peak flow in a small catchment upstream of a road in SE Norway on an hourly basis. All four models were calibrated using hourly observed streamflow. Simulated and observed discharge generated during three types of hydrological situations characteristic of winter/spring conditions causing overland flow were considered: snowmelt, partially frozen soil and heavy rain events. Using parameter sets optimised for winter/spring conditions, flows simulated by HBV coupled with CoupModel were comparable to measured discharge from the catchment in corresponding periods. However, this combination was best when all the parameters were calibrated in HBV. For ungauged basins with no real-time monitoring of discharge and when the spatial distribution is important, MIKE SHE may be more suitable than the other models, but the lack of detailed input data and the uncertainty in physical parameters should be considered. LISEM is potentially capable of calculating runoff from small catchments during winter/spring but requires better description of snowmelt, infiltration into frozen layers and tile drainage. From a practical road maintenance perspective, the usefulness and accuracy of a model depends on its ability to represent site-specific processes, data availability and calibration requirements.

  20. Characterizing the proposed geologic repository for high-level radioactive waste at Yucca Mountain, Nevada--hydrology and geochemistry

    Science.gov (United States)

    Stuckless, John S.; Levich, Robert A.

    2012-01-01

    This hydrology and geochemistry volume is a companion volume to the 2007 Geological Society of America Memoir 199, The Geology and Climatology of Yucca Mountain and Vicinity, Southern Nevada and California, edited by Stuckless and Levich. The work in both volumes was originally reported in the U.S. Department of Energy regulatory document Yucca Mountain Site Description, for the site characterization study of Yucca Mountain, Nevada, as the proposed U.S. geologic repository for high-level radioactive waste. The selection of Yucca Mountain resulted from a nationwide search and numerous committee studies during a period of more than 40 yr. The waste, largely from commercial nuclear power reactors and the government's nuclear weapons programs, is characterized by intense penetrating radiation and high heat production, and, therefore, it must be isolated from the biosphere for tens of thousands of years. The extensive, unique, and often innovative geoscience investigations conducted at Yucca Mountain for more than 20 yr make it one of the most thoroughly studied geologic features on Earth. The results of these investigations contribute extensive knowledge to the hydrologic and geochemical aspects of radioactive waste disposal in the unsaturated zone. The science, analyses, and interpretations are important not only to Yucca Mountain, but also to the assessment of other sites or alternative processes that may be considered for waste disposal in the future. Groundwater conditions, processes, and geochemistry, especially in combination with the heat from radionuclide decay, are integral to the ability of a repository to isolate waste. Hydrology and geochemistry are discussed here in chapters on unsaturated zone hydrology, saturated zone hydrology, paleohydrology, hydrochemistry, radionuclide transport, and thermally driven coupled processes affecting long-term waste isolation. This introductory chapter reviews some of the reasons for choosing to study Yucca Mountain as a

  1. Characterizing the proposed geologic repository for high-level radioactive waste at Yucca Mountain, Nevada: hydrology and geochemistry

    Science.gov (United States)

    Stuckless, John S.; Levich, Robert A.

    2012-01-01

    This hydrology and geochemistry volume is a companion volume to the 2007 Geological Society of America Memoir 199, The Geology and Climatology of Yucca Mountain and Vicinity, Southern Nevada and California, edited by Stuckless and Levich. The work in both volumes was originally reported in the U.S. Department of Energy regulatory document Yucca Mountain Site Description, for the site characterization study of Yucca Mountain, Nevada, as the proposed U.S. geologic repository for high-level radioactive waste. The selection of Yucca Mountain resulted from a nationwide search and numerous committee studies during a period of more than 40 yr. The waste, largely from commercial nuclear power reactors and the government's nuclear weapons programs, is characterized by intense penetrating radiation and high heat production, and, therefore, it must be isolated from the biosphere for tens of thousands of years. The extensive, unique, and often innovative geoscience investigations conducted at Yucca Mountain for more than 20 yr make it one of the most thoroughly studied geologic features on Earth. The results of these investigations contribute extensive knowledge to the hydrologic and geochemical aspects of radioactive waste disposal in the unsaturated zone. The science, analyses, and interpretations are important not only to Yucca Mountain, but also to the assessment of other sites or alternative processes that may be considered for waste disposal in the future. Groundwater conditions, processes, and geochemistry, especially in combination with the heat from radionuclide decay, are integral to the ability of a repository to isolate waste. Hydrology and geochemistry are discussed here in chapters on unsaturated zone hydrology, saturated zone hydrology, paleohydrology, hydrochemistry, radionuclide transport, and thermally driven coupled processes affecting long-term waste isolation. This introductory chapter reviews some of the reasons for choosing to study Yucca Mountain as a

  2. Study of runoff generation responding to varied catchment morphology

    Science.gov (United States)

    Zhang, Jun; Han, Dawei

    2017-04-01

    Hydrological processes are inevitably related to the catchment morphology, which includes hillslope, area, shape and drainage network, etc. The topic has attracted attentions of numerous studies on it. The previous studies mostly compare runoff generation processes in various catchments to derive empirical equations. However, due to the variability of catchment properties and climate conditions, it is highly possible that other factors would compound the results when one tries to focus on one particular catchment property. In this study, virtual catchments are built based on an actual catchment, the Brue catchment in UK. These catchments are assigned with varied morphology, including hillslope, area, width and length etc., and are simulated using a fully distributed model. When one catchment property is tested, the other properties are assumed as control variables. The whole hydrological processes are compared among all the catchments, in which the time to peak (Tp) and peak volume (Qp) are mainly considered as the assessment indicators. The results show that catchment morphology has significant influence on runoff generation. To illustrate, when the average slope of the catchment increases, the peak volume increases and the time to peak decreases following particular curves. Moreover, when the slope increases to a certain threshold level, the influence of slope on runoff generation is plateaued. An empirical model is built according to the results, which is able to provide a useful guide for runoff generation in varied catchments.

  3. [Hydrologic processes of the different landscape zones in Fenhe River headwater catchment].

    Science.gov (United States)

    Yang, Yong-Gang; Li, Cai-Mei; Qin, Zuo-Dong; Zou, Song-Bing

    2014-06-01

    There are few studies on the hydrologic processes of the landscape zone scales at present. Since the water environment is worsening, there is sharp contradiction between supply and demand of water resources in Shanxi province. The principle of the hydrologic processes of the landscape zones in Fenhe River headwater catchment was revealed by means of isotope tracing, hydrology geological exploration and water chemical signal study. The results showed that the subalpine meadow zone and the medium high mountain forest zone were main runoff formation regions in Fenhe River headwater catchment, while the sparse forest shrub zone and the mountain grassland zone lagged the temporal and spatial collection of the precipitation. Fenhe River water was mainly recharged by precipitation, groundwater, melt water of snow and frozen soil. This study suggested that the whole catchment precipitation hardly directly generated surface runoff, but was mostly transformed into groundwater or interflow, and finally concentrated into river channel, completed the "recharge-runoff-discharge" hydrologic processes. This study can provide scientific basis and reference for the containment of water environment deterioration, and is expected to deliver the comprehensive restoration of clear-water reflowing and the ecological environment in Shanxi province.

  4. Summer Freezing Resistance: A Critical Filter for Plant Community Assemblies in Mediterranean High Mountains.

    Science.gov (United States)

    Pescador, David S; Sierra-Almeida, Ángela; Torres, Pablo J; Escudero, Adrián

    2016-01-01

    Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain) by measuring their ice nucleation temperature, freezing point (FP), and low-temperature damage (LT50), as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance). The community response to freezing was estimated for each plot as community weighted means (CWMs) and functional diversity (FD), and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content (LDMC), and seed mass). There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50 responded negatively to altitude, whereas the FD of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50 varied among growth forms, and only leaf dry matter content was negatively correlated with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower FD of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to be a general prerequisite for plants

  5. Denitrification and Biodiversity of Denitrifiers in a High-Mountain Mediterranean Lake.

    Science.gov (United States)

    Castellano-Hinojosa, Antonio; Correa-Galeote, David; Carrillo, Presentación; Bedmar, Eulogio J; Medina-Sánchez, Juan M

    2017-01-01

    Wet deposition of reactive nitrogen (Nr) species is considered a main factor contributing to N inputs, of which nitrate ([Formula: see text]) is usually the major component in high-mountain lakes. The microbial group of denitrifiers are largely responsible for reduction of nitrate to molecular dinitrogen (N2) in terrestrial and aquatic ecosystems, but the role of denitrification in removal of contaminant nitrates in high-mountain lakes is not well understood. We have used the oligotrophic, high-altitude La Caldera lake in the Sierra Nevada range (Spain) as a model to study the role of denitrification in nitrate removal. Dissolved inorganic Nr concentration in the water column of la Caldera, mainly nitrate, decreased over the ice-free season which was not associated with growth of microbial plankton or variations in the ultraviolet radiation. Denitrification activity, estimated as nitrous oxide (N2O) production, was measured in the water column and in sediments of the lake, and had maximal values in the month of August. Relative abundance of denitrifying bacteria in sediments was studied by quantitative polymerase chain reaction of the 16S rRNA and the two phylogenetically distinct clades nosZI and nosZII genes encoding nitrous oxide reductases. Diversity of denitrifiers in sediments was assessed using a culture-dependent approach and after the construction of clone libraries employing the nosZI gene as a molecular marker. In addition to genera Polymorphum, Paracoccus, Azospirillum, Pseudomonas, Hyphomicrobium, Thauera, and Methylophaga, which were present in the clone libraries, Arthrobacter, Burkholderia, and Rhizobium were also detected in culture media that were not found in the clone libraries. Analysis of biological activities involved in the C, N, P, and S cycles from sediments revealed that nitrate was not a limiting nutrient in the lake, allowed N2O production and determined denitrifiers' community structure. All these results indicate that denitrification

  6. Metabolic processes sustaining the reviviscence of lichen Xanthoria elegans (Link) in high mountain environments.

    Science.gov (United States)

    Aubert, Serge; Juge, Christine; Boisson, Anne-Marie; Gout, Elisabeth; Bligny, Richard

    2007-10-01

    To survive in high mountain environments lichens must adapt themselves to alternating periods of desiccation and hydration. Respiration and photosynthesis of the foliaceous lichen, Xanthoria elegans, in the dehydrated state were below the threshold of CO2-detection by infrared gas analysis. Following hydration, respiration totally recovered within seconds and photosynthesis within minutes. In order to identify metabolic processes that may contribute to the quick and efficient reactivation of lichen physiological processes, we analysed the metabolite profile of lichen thalli step by step during hydration/dehydration cycles, using 31P- and 13C-NMR. It appeared that the recovery of respiration was prepared during dehydration by the accumulation of a reserve of gluconate 6-P (glcn-6-P) and by the preservation of nucleotide pools, whereas glycolytic and photosynthetic intermediates like glucose 6-P and ribulose 1,5-diphosphate were absent. The large pools of polyols present in both X. elegans photo- and mycobiont are likely to contribute to the protection of cell constituents like nucleotides, proteins, and membrane lipids, and to preserve the integrity of intracellular structures during desiccation. Our data indicate that glcn-6-P accumulated due to activation of the oxidative pentose phosphate pathway, in response to a need for reducing power (NADPH) during the dehydration-triggered down-regulation of cell metabolism. On the contrary, glcn-6-P was metabolised immediately after hydration, supplying respiration with substrates during the replenishment of pools of glycolytic and photosynthetic intermediates. Finally, the high net photosynthetic activity of wet X. elegans thalli at low temperature may help this alpine lichen to take advantage of brief hydration opportunities such as ice melting, thus favouring its growth in harsh high mountain climates.

  7. Even between-lap pacing despite high within-lap variation during mountain biking.

    Science.gov (United States)

    Martin, Louise; Lambeth-Mansell, Anneliese; Beretta-Azevedo, Liane; Holmes, Lucy A; Wright, Rachel; St Clair Gibson, Alan

    2012-09-01

    Given the paucity of research on pacing strategies during competitive events, this study examined changes in dynamic high-resolution performance parameters to analyze pacing profiles during a multiple-lap mountain-bike race over variable terrain. A global-positioning-system (GPS) unit (Garmin, Edge 305, USA) recorded velocity (m/s), distance (m), elevation (m), and heart rate at 1 Hz from 6 mountain-bike riders (mean±SD age=27.2±5.0 y, stature=176.8±8.1 cm, mass=76.3±11.7 kg, VO2max=55.1±6.0 mL·kg(-1)·min1) competing in a multilap race. Lap-by-lap (interlap) pacing was analyzed using a 1-way ANOVA for mean time and mean velocity. Velocity data were averaged every 100 m and plotted against race distance and elevation to observe the presence of intralap variation. There was no significant difference in lap times (P=.99) or lap velocity (P=.65) across the 5 laps. Within each lap, a high degree of oscillation in velocity was observed, which broadly reflected changes in terrain, but high-resolution data demonstrated additional nonmonotonic variation not related to terrain. Participants adopted an even pace strategy across the 5 laps despite rapid adjustments in velocity during each lap. While topographical and technical variations of the course accounted for some of the variability in velocity, the additional rapid adjustments in velocity may be associated with dynamic regulation of self-paced exercise.

  8. Spatial distribution and temporal development of high-mountain lakes in western Austria

    Science.gov (United States)

    Merkl, Sarah; Emmer, Adam; Mergili, Martin

    2015-04-01

    Glacierized high-mountain environments are characterized by active morphodynamics, favouring the rapid appearance and disappearance of lakes. On the one hand, such lakes indicate high-mountain environmental changes such as the retreat of glaciers. On the other hand, they are sometimes susceptible to sudden drainage, leading to glacial lake outburst floods (GLOFs) putting the downstream population at risk. Whilst high-mountain lakes have been intensively studied in the Himalayas, the Pamir, the Andes or the Western Alps, this is not the case for the Eastern Alps. A particular research gap, which is attacked with the present work, concerns the western part of Austria. We consider a study area of approx. 6,140 km², covering the central Alps over most of the province of Tyrol and part of the province of Salzburg. All lakes ≥250 m² located higher than 2000 m asl are mapped from high-resolution Google Earth imagery and orthophotos. The lakes are organized into seven classes: (i) ice-dammed; near-glacial (ii) moraine-dammed and (iii) bedrock-dammed; (iv) moraine-dammed and (v) bedrock-dammed distant to the recent glaciers; (vi) landslide-dammed; (vii) anthropogenic. The temporal development of selected lakes is investigated in detail, using aerial photographs dating back to the 1950s. 1045 lakes are identified in the study area. Only eight lakes are ice-dammed (i). One third of all lakes is located in the immediate vicinity of recent glacier tongues, half of them impounded by moraine (ii), half of them by bedrock (iii). Two thirds of all lakes are impounded by features (either moraines or bedrock) shaped by LIA or Pleistocenic glaciers at some distance to the present glacier tongues (iv and v). Only one landslide-dammed lake (vi) is identified in the study area, whilst 21 lakes are of anthropogenic origin (vii). 72% of all lakes are found at 2250-2750 m asl whilst less than 2% are found above 3000 m asl. The ratio of rock-dammed lakes increases with increasing

  9. Topographical and Hydrological Influences on the Spatial Distribution of Mercury at the Catchment Scale

    Science.gov (United States)

    Gunda, T.; Converse, A.; Riscassi, A.; Scanlon, T. M.

    2009-12-01

    Inorganic forms of mercury (Hg) can be converted through natural processes into methylmercury, a highly potent neurotoxin that can bioaccumulate in food chains and pose a risk to human health. Although Hg can enter aquatic environments through direct deposition, the predominant source tends to be mobilized Hg deposited in nearby terrestrial systems. Therefore, understanding the complex intermediate Hg cycling in vegetation and soils is crucial to predicting its presence in water bodies and potential for bioaccumulation. While prior studies have revealed dependence of Hg distribution on forest types and soil characteristics, less attention has been given to the role of aspect and hydrological factors on Hg deposition and consequent spatial distribution within catchments. My research addresses this by conducting a litterfall and soil sampling study to assess Hg spatial distribution within two paired catchments: northwest-facing North Fork Dry Run and southeast-facing Hannah Run. Litterfall and soil samples collected through a random stratified sampling process were analyzed for total Hg concentrations using a Cold Vapor Atomic Fluorescence Spectrometry. An analysis of variance conducted on leaf litter and soil Hg concentrations revealed that: (1) Hg accumulation in soils was significantly greater in the northwest-facing catchment than in the south-east facing catchment, while Hg accumulation in leaves was not found to differ, and (2) within each catchment the likelihood of saturation was not found to play a significant role in governing Hg accumulation in soils. Higher Hg levels in the soils of North Forth Dry Run could be attributable to predominant wind direction from sources of Hg (i.e., coal-burning power plants). Within catchments, lack of appreciable Hg deposition resulted in statistically insignificant variation amongst topographic index classes. The results of this study reveal the potential implications of mountainous terrains in distributing Hg arising from

  10. Contrasting trends in floods for two sub-arctic catchments in northern Sweden – does glacier presence matter?

    Directory of Open Access Journals (Sweden)

    H. E. Dahlke

    2012-07-01

    Full Text Available Our understanding is limited to how transient changes in glacier response to climate warming will influence the catchment hydrology in the Arctic and Sub-Arctic. This understanding is particularly incomplete for flooding extremes because understanding the frequency of such unusual events requires long records of observation not often available for the Arctic and Sub-Arctic. This study presents a statistical analysis of trends in the magnitude and timing of flood extremes and the mean summer discharge in two sub-arctic catchments, Tarfala and Abisko, in northern Sweden. The catchments have different glacier covers (30% and 1%, respectively. Statistically significant trends (at the 5% level were identified for both catchments on an annual and on a seasonal scale (3-months averages using the Mann-Kendall trend test. Stationarity of flood records was tested by analyzing trends in the flood quantiles, using generalized least squares regression. Hydrologic trends were related to observed changes in the precipitation and air temperature, and were correlated with 3-months averaged climate pattern indices (e.g. North Atlantic oscillation. Both catchments showed a statistically significant increase in the annual mean air temperature over the comparison time period of 1985–2009 (Tarfala and Abisko p<0.01, but did not show significant trends in the total precipitation (Tarfala p = 0.91, Abisko p = 0.44. Despite the similar climate evolution over the studied period in the two catchments, data showed contrasting trends in the magnitude and timing of flood peaks and the mean summer discharge. Hydrologic trends indicated an amplification of the streamflow and flood response in the highly glacierized catchment and a dampening of the response in the non-glacierized catchment. The glacierized mountain catchment showed a statistically significant increasing trend in the flood magnitudes (p = 0.04 that is clearly correlated to the

  11. Dataset of Passerine bird communities in a Mediterranean high mountain (Sierra Nevada, Spain)

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Barea-Azcón, José Miguel; Álvarez-Ruiz, Lola; Bonet-García, Francisco Javier; Zamora, Regino

    2016-01-01

    Abstract In this data paper, a dataset of passerine bird communities is described in Sierra Nevada, a Mediterranean high mountain located in southern Spain. The dataset includes occurrence data from bird surveys conducted in four representative ecosystem types of Sierra Nevada from 2008 to 2015. For each visit, bird species numbers as well as distance to the transect line were recorded. A total of 27847 occurrence records were compiled with accompanying measurements on distance to the transect and animal counts. All records are of species in the order Passeriformes. Records of 16 different families and 44 genera were collected. Some of the taxa in the dataset are included in the European Red List. This dataset belongs to the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:26865820

  12. Large-Scale Seasonal Changes in Glacier Thickness Across High Mountain Asia

    Science.gov (United States)

    Wang, Qiuyu; Yi, Shuang; Chang, Le; Sun, Wenke

    2017-10-01

    Recently, increased efforts have been made to estimate the mass budgets of glaciers in High Mountain Asia (HMA). However, seasonal changes in glaciers are poorly understood, despite the fact that seasonal meltwater released from glaciers is a crucial local water resource in HMA. Utilizing satellite altimetry and gravimetry data, we constructed annual changes in glacier elevation and identified two general patterns of the seasonality of glacier elevation changes. Glaciers in the periphery of HMA (except for those in the eastern Himalayas) thicken from approximately December to April-June, thus exhibiting winter and spring accumulation. Glaciers in the inner Tibetan Plateau, especially those in Western Kunlun and Tanggula, accumulate from approximately March to approximately August, thus exhibiting spring and summer accumulation. The amounts of seasonal glacier ablation were obtained using a new approach of direct observations of glacier changes, rather than inferring changes using a climate model.

  13. Role of glaciers in watershed hydrology: a preliminary study of a "Himalayan catchment"

    Directory of Open Access Journals (Sweden)

    R. J. Thayyen

    2010-02-01

    Full Text Available A large number of Himalayan glacier catchments are under the influence of humid climate with snowfall in winter (November–April and south-west monsoon in summer (June–September dominating the regional hydrology. Such catchments are defined as "Himalayan catchment", where the glacier meltwater contributes to the river flow during the period of annual high flows produced by the monsoon. The winter snow dominated Alpine catchments of the Kashmir and Karakoram region and cold-arid regions of the Ladakh mountain range are the other major glacio-hydrological regimes identified in the region. Factors influencing the river flow variations in a "Himalayan catchment" were studied in a micro-scale glacier catchment in the Garhwal Himalaya, covering an area of 77.8 km2. Three hydrometric stations were established at different altitudes along the Din Gad stream and discharge was monitored during the summer ablation period from 1998 to 2004, with an exception in 2002. These data have been analysed along with winter/summer precipitation, temperature and mass balance data of the Dokriani glacier to study the role of glacier and precipitation in determining runoff variations along the stream continuum from the glacier snout to 2360 m a.s.l. The study shows that the inter-annual runoff variation in a "Himalayan catchment" is linked with precipitation rather than mass balance changes of the glacier. This study also indicates that the warming induced an initial increase of glacier runoff and subsequent decline as suggested by the IPCC (2007 is restricted to the glacier degradation-derived component in a precipitation dominant Himalayan catchment and cannot be translated as river flow response. The preliminary assessment suggests that the "Himalayan catchment" could experience higher river flows and positive glacier mass balance regime together in association with strong monsoon. The important role of glaciers in this precipitation dominant system is

  14. Use of Uas in a High Mountain Landscape: the Case of Gran Sommetta Rock Glacier (ao)

    Science.gov (United States)

    Dall'Asta, E.; Delaloye, R.; Diotri, F.; Forlani, G.; Fornari, M.; Morra di Cella, U.; Pogliotti, P.; Roncella, R.; Santise, M.

    2015-08-01

    Photogrammetry has been used since long time to periodically control the evolution of landslides, either from aerial images as well as from ground. Landslides control and monitoring systems face a large variety of cases and situations: in hardly accessible environments, like glacial areas and high mountain locations, it is not simple finding a survey method and a measurement control system, which are capable to reliably assess, with low costs, the expected displacement and its accuracy. For this reason, the behaviour of these events presents the geologists and the surveyor each time with different challenges. The use of UAS (Unmanned Aerial System) represents, in this context, a recent and valid option to perform the data acquisition both in safety and quickly, avoiding hazards and risks for the operators while at the same time containing the costs. The paper presents an innovative monitoring system based on UAS-photogrammetry, GNSS survey and DSM change detection techniques to evaluate the Gran Sommetta rock glacier surface movements over the period 2012-2014. Since 2012, the surface movements of the glacier are monitored by ARPAVdA (a regional environmental protection agency) as a case study for the impact of climate change on high-mountain infrastructures. In such scenarios, in fact, a low-cost monitoring activity can provide important data to improve our knowledge about glacier dynamics connected to climate changes and to prevent risks in anthropic Alps areas. To evaluate the displacements of the rock glacier different techniques were proposed: the most reliable uses the orthophoto of the area and rely on a manual identification of corresponding features performed by a trained operator. To further limit the costs and improve the density of displacement information two automatic procedures were developed as well.

  15. A spatially resolved estimate of High Mountain Asia glacier mass balances from 2000 to 2016

    Science.gov (United States)

    Brun, Fanny; Berthier, Etienne; Wagnon, Patrick; Kääb, Andreas; Treichler, Désirée

    2017-09-01

    High Mountain Asia hosts the largest glacier concentration outside the polar regions. These glaciers are important contributors to streamflow in one of the most populated areas of the world. Past studies have used methods that can provide only regionally averaged glacier mass balances to assess the glacier contribution to rivers and sea level rise. Here we compute the mass balance for about 92% of the glacierized area of High Mountain Asia using time series of digital elevation models derived from satellite stereo-imagery. We calculate a total mass change of -16.3 +/- 3.5 Gt yr-1 (-0.18 +/- 0.04 m w.e. yr-1) between 2000 and 2016, which is less negative than most previous estimates. Region-wide mass balances vary from -4.0 +/- 1.5 Gt yr-1 (-0.62 +/- 0.23 m w.e. yr-1) in Nyainqentanglha to +1.4 +/- 0.8 Gt yr-1 (+0.14 +/- 0.08 m w.e. yr-1) in Kunlun, with large intra-regional variability of individual glacier mass balances (standard deviation within a region ~0.20 m w.e. yr-1). Specifically, our results shed light on the Nyainqentanglha and Pamir glacier mass changes, for which contradictory estimates exist in the literature. They provide crucial information for the calibration of the models used for projecting glacier response to climatic change, as these models do not capture the pattern, magnitude and intra-regional variability of glacier changes at present.

  16. Interpreting landscape change in high mountains of northeastern Oregon from long-term repeat photography.

    Science.gov (United States)

    Jon M. Skovlin; Gerald S. Strickler; Jesse L. Peterson; Arthur W. Sampson

    2001-01-01

    We compared 45 photographs taken before 1925 to photographs taken as late as 1999 and documented landscape changes above 5,000 feet elevation in the Wallowa, Elkhorn, and Greenhorn Mountains of northeastern Oregon. We noted the following major changes from these comparisons: (1) the expansion of subalpine fir into mountain grasslands, (2) the invasion of moist and wet...

  17. High concentrations of regional dust from deserts to plains across the central Rocky Mountains, USA

    Science.gov (United States)

    Reynolds, R. L.; Munson, S. M.; Fernandez, D. P.; Neff, J. C.

    2015-12-01

    Regional mineral dust in the American Southwest affects snow-melt rates, biogeochemical cycling, visibility, and public health. We measured total suspended particulates (TSP) across a 500-km-long sampling network of five remote sites in Utah and Colorado, USA, forming a gradient in distance from major dust emitting areas. The two westernmost sites on the Colorado Plateau desert had similar TSP concentrations (2008-2012, daily average=126 μg m-3; max. daily average over a two-week period=700 μg m-3 at Canyonlands National Park, Utah), while the easternmost High Plains site, close to cropped and grazed areas in northeastern Colorado, had an average concentration of 143 μg m-3 in 2011-2012 (max. daily average=656 μg m-3). Such concentrations rank comparably with those of TSP in several African and Asian cities in the paths of frequent dust storms. Dust loadings at the two intervening montane sites decreased from the western slope of the Rocky Mountains (Telluride, daily average=68 μg m-3) to an eastern site (Niwot Ridge, daily average=58 μg m-3). Back-trajectory analyses and satellite retrievals indicated that the three westernmost sites received most dust from large desert-source regions as far as 300 km to their southwest. These sources also sometimes sent dust to the two easternmost sites, which additionally captured dust from sources north and northwest of the central Rocky Mountains as well as locally at the Plains site. The PM10 fraction accounted for Asia.

  18. Modelling magma-drift interaction at the proposed high-level radioactive waste repository at Yucca Mountain, Nevada, USA

    NARCIS (Netherlands)

    Woods, Andrew W.; Sparks, Steve; Bokhove, Onno; Lejeune, Anne-Marie; Connor, Charles B.; Hill, Britain E.

    2002-01-01

    We examine the possible ascent of alkali basalt magma containing 2 wt percent water through a dike and into a horizontal subsurface drift as part of a risk assessment for the proposed high-level radioactive waste repository beneath Yucca Mountain, Nevada, USA. On intersection of the dike with the

  19. Surviving at high elevations: an inter- and intra-specific analysis in a mountain bird community.

    Science.gov (United States)

    Bastianelli, G; Tavecchia, G; Meléndez, L; Seoane, J; Obeso, J R; Laiolo, P

    2017-06-01

    Elevation represents an important selection agent on self-maintenance traits and correlated life histories in birds, but no study has analysed whether life-history variation along this environmental cline is consistent among and within species. In a sympatric community of passerines, we analysed how the average adult survival of 25 open-habitat species varied with their elevational distribution and how adult survival varied with elevation at the intra-specific level. For such purpose, we estimated intra-specific variation in adult survival in two mountainous species, the Water pipit (Anthus spinoletta) and the Northern wheatear (Oenanthe oenanthe) in NW Spain, by means of capture-recapture analyses. At the inter-specific level, high-elevation species showed higher survival values than low elevation ones, likely because a greater allocation to self-maintenance permits species to persist in alpine environments. At the intra-specific level, the magnitude of survival variation was lower by far. Nevertheless, Water pipit survival slightly decreased at high elevations, while the proportion of transient birds increased. In contrast, no such relationships were found in the Northern wheatear. Intra-specific analyses suggest that living at high elevation may be costly, such as for the Water pipit in our case study. Therefore, it seems that a species can persist with viable populations in uplands, where extrinsic mortality is high, by increasing the investment in self-maintenance and prospecting behaviours.

  20. Environmental constraints on plant transpiration and the hydrological implications in a northern high latitude upland headwater catchment

    Science.gov (United States)

    Wang, H.; Tetzlaff, D.; Soulsby, C.

    2016-12-01

    Vegetation affects water, carbon and energy transfer in the soil-plant-atmosphere system and mediates land-atmosphere interactions by altering surface albedo, roughness and soil macro-porosity, intercepting rainfall and transpiring water from soil layers. Vegetation water use (Ec) is regulated by stomata behaviour which is constrained by environmental variables including radiation, temperature, vapour pressure deficit, and soil water content. The relative influences of these variables on Ec are usually site specific reflecting climate and species differences. At a catchment scale, Ec can account for a large proportion of total evapotranspiration, and hence regulates water storage and fluxes in the soils, groundwater reservoirs and streams. In this study, we estimated transpiration from short vegetation (Calluna vulgaris) using the Maximum Entropy Production model (MEP), and measured sap flow of two forest plantations, together with meteorological variables, soil moisture and streamflow in an upland headwater catchment in northern Scotland. Our objectives were to investigate the environmental constraints on Ec in this wet humid and cool summer climate, and the hydrological responses and regulations of Ec in terms of rainfall and streamflow. Results will assist the assessment of hydrological implications of land management in terms of afforestation/deforestation.

  1. Influence of Large-Scale Circulation on the Dynamics of Extratropical Cyclones and Orographic Precipitation in High Mountain Asia

    Science.gov (United States)

    Cannon, Forest Glen

    Westerly disturbances are the primary climatic influence within High Mountain Asia during winter, producing over half of annual precipitation in 4-6 events per winter season and supplying essential water resources for large populations across Asia. This research examines High Mountain Asia's hydroclimate, focusing on the relationship between westerly disturbance dynamics, the mechanisms that drive orographic precipitation, and their variability on intraseasonal and interannual scales. The first chapter establishes that extreme winter precipitation events in High Mountain Asia are primarily attributable to combined contributions from dynamical forcing and moisture availability during westerly disturbance interaction with regional topography. A novel wave-tracking algorithm was developed to provide an inventory of location, timing, intensity, and duration of westerly disturbance events, allowing for a comprehensive study of the mechanisms that drive orographic precipitation, on an individual event basis and in the aggregate. In the second chapter, westerly disturbances are investigated using extreme event composites to identify significant influence of global atmospheric variability over westerly disturbance dynamics and moisture availability, focusing on tropical forcing by the Madden Julian Oscillation on intraseasonal timescales and the El Nino Southern Oscillation on interannual scales. This work demonstrates that El Nino simultaneously enhances the strength of the storm track and moisture availability to westerly disturbances. Contrastingly, during Madden Julian Oscillation propagation there is a transition in the balance of contributions from moisture availability and dynamical forcing to orographic precipitation. The third chapter of this dissertation employs a mesoscale model to perform a set of modified topography experiments in which extreme precipitation events in High Mountain Asia that were related to westerly disturbances are simulated at 6km resolution

  2. Rockfall hazard in high mountain areas increased by the current atmospheric warming

    Science.gov (United States)

    Ravanel, Ludovic; Deline, Philip

    2013-04-01

    The study of rockfall (volume > 100 m3) in high mountains is essential to understand landscape evolution and to evaluate natural hazard. The number of rockfalls seems actually to rise in the European Alps, while vulnerability is increasing from high elevation areas (e.g. cable cars, huts) to valley floors (e.g. urbanization, transport). Recent rockfalls from high-Alpine steep rockwalls are hypothesized to be a consequence of the climate change through the warming of the permafrost. Given the lack of systematic data on rockfall, this relationship has however remained difficult to assess despite few evidences including laboratory tests and temperature measurements indicating permafrost degradation, while the increase of rockfall frequency and magnitude remained conjectural. Here we analyse several inventories of rockfalls acquired in the Mont Blanc massif (France and Italy) by innovative methods in order to characterize the rockfall triggering conditions and to emphasize the role of permafrost: (i) In two sectors of the massif (Drus and Aiguilles de Chamonix), a comparison of photographs from the end of the Little Ice Age to 2011, combined with field geomorphological data, allowed the identification of more than 50 rockfalls during this period, ranging in volume from 500 to 265,000 m3. (ii) A network of local observers (guides, hut keepers, mountaineers) allowed the documentation of all rockfalls occurred in 2007 (n = 45), 2008 (22), 2009 (72), 2010 (47) and 2011 (65) in the central part of the Mont Blanc massif, ranging in volume from 100 to 43,000 m3. Furthermore, 182 rockfalls were identified at the end of the 2003 Summer heatwave through the analysis of a satellite image of the whole massif. A strong correlation between the rockfall occurrences and the hottest periods at the time scales of the century and the year strengthens the hypothesis of the relationship between permafrost degradation and rockfall at high elevation. Moreover, (i) modelling suggests the

  3. Contrasting response of glacierized catchments in the Central Himalaya and the Central Andes to climate change

    Science.gov (United States)

    Ragettli, Silvan; Pellicciotti, Francesca; Immerzeel, Walter

    2015-04-01

    The Andes of South America and the Himalaya in high-mountain Asia are two regions where advanced simulation models are of vital importance to anticipate the impacts of climate change on water resources. The two mountain systems hold the largest ice masses outside the polar regions. Major rivers originate here and downstream regions are densely populated. In the long run, glacier recession generates concerns about the sustainability of summer runoff. This study benefits from recent efforts of carefully planned short-term field experiments in two headwater catchments in the Central Andes of Chile and in the Central Himalaya in Nepal. The two study catchments contrast in terms of their climate and in the characteristics of their glaciers. A systematic approach is developed, built upon the available local data, to reduce the predictive uncertainty of a state-of-the-art glacio-hydrological model used for the projection of 21st century glacier changes and catchment runoff. The in-situ data are used for model development and step-wise, multivariate parameter calibration. Catchment runoff and remotely sensed MODIS and Landsat snow cover are used for model validation. The glacio-hydrological model simulates the water cycle with a high temporal (hourly time steps) and spatial (100 m grid cells) resolution and accounts for processes typical of both regions like glacier melt under debris cover or mass redistribution through avalanching. Future projections are based on the outputs of twelve stochastically downscaled global climate models for two emission scenarios (RCP 4.5 and RCP 8.5). This is one of the first truly intercomparative modeling studies at the catchment scale across mountain regions of the world to assess and compare future changes in glaciers and snow cover and associated impacts on streamflow production. Both catchments will experience significant glacier mass loss throughout the twenty-first century. However, the trajectories of simulated future runoff and

  4. Hydrological Modeling of the Upper Indus Basin: A Case Study from a High-Altitude Glacierized Catchment Hunza

    Directory of Open Access Journals (Sweden)

    Khan Garee

    2017-01-01

    Full Text Available The Soil andWater Assessment Tool (SWAT model combined with a temperature index and elevation band algorithm was applied to the Hunza watershed, where snow and glacier-melt are the major contributor to river flow. This study’s uniqueness is its use of a snow melt algorithm (temperature index with elevation bands combined with the SWAT, applied to evaluate the performance of the SWAT model in the highly snow and glacier covered watershed of the Upper Indus Basin in response to climate change on future streamflow volume at the outlet of the Hunza watershed, and its contribution to the Indus River System in both space and time, despite its limitation; it is not designed to cover the watershed of heterogeneous mountains. The model was calibrated for the years 1998–2004 and validated for the years 2008–2010. The model performance is evaluated using the four recommended statistical coefficients with uncertainty analysis (p-factor and r-factor. Simulations generated good calibration and validation results for the daily flow gauge. The model efficiency was evaluated, and a strong relationship was observed between the simulated and observed flows. The model results give a coefficient of determination (R2 of 0.82 and a Nash–Sutcliffe Efficiency index (NS of 0.80 for the daily flow with values of p-factor (79% and r-factor (76%. The SWAT model was also used to evaluate climate change impact on hydrological regimes, the target watershed with three GCMs (General Circulation Model of the IPCC fifth report for 2030–2059 and 2070–2099, using 1980–2010 as the control period. Overall, temperature (1.39 C to 6.58 C and precipitation (31% indicated increased variability at the end of the century with increasing river flow (5%–10%; in particular, the analysis showed smaller absolute changes in the hydrology of the study area towards the end of the century. The results revealed that the calibrated model was more sensitive towards temperature and

  5. How no-man’s-land is now everyone’s problem: the renowned Cape flora is everywhere in retreat as runaway pine invasions transform the Outeniqua and Tsitsikamma mountains

    CSIR Research Space (South Africa)

    Cowling, R

    2009-09-01

    Full Text Available as a result of a failure of mountain catchments to deliver ample, clean water as they do today. In this possible future, fires would rage with abnormal intensity, seriously threatening homes, crops, plantations and people. The high-intensity fires would...

  6. Denitrification and Biodiversity of Denitrifiers in a High-Mountain Mediterranean Lake

    Directory of Open Access Journals (Sweden)

    Antonio Castellano-Hinojosa

    2017-10-01

    Full Text Available Wet deposition of reactive nitrogen (Nr species is considered a main factor contributing to N inputs, of which nitrate (NO3− is usually the major component in high-mountain lakes. The microbial group of denitrifiers are largely responsible for reduction of nitrate to molecular dinitrogen (N2 in terrestrial and aquatic ecosystems, but the role of denitrification in removal of contaminant nitrates in high-mountain lakes is not well understood. We have used the oligotrophic, high-altitude La Caldera lake in the Sierra Nevada range (Spain as a model to study the role of denitrification in nitrate removal. Dissolved inorganic Nr concentration in the water column of la Caldera, mainly nitrate, decreased over the ice-free season which was not associated with growth of microbial plankton or variations in the ultraviolet radiation. Denitrification activity, estimated as nitrous oxide (N2O production, was measured in the water column and in sediments of the lake, and had maximal values in the month of August. Relative abundance of denitrifying bacteria in sediments was studied by quantitative polymerase chain reaction of the 16S rRNA and the two phylogenetically distinct clades nosZI and nosZII genes encoding nitrous oxide reductases. Diversity of denitrifiers in sediments was assessed using a culture-dependent approach and after the construction of clone libraries employing the nosZI gene as a molecular marker. In addition to genera Polymorphum, Paracoccus, Azospirillum, Pseudomonas, Hyphomicrobium, Thauera, and Methylophaga, which were present in the clone libraries, Arthrobacter, Burkholderia, and Rhizobium were also detected in culture media that were not found in the clone libraries. Analysis of biological activities involved in the C, N, P, and S cycles from sediments revealed that nitrate was not a limiting nutrient in the lake, allowed N2O production and determined denitrifiers’ community structure. All these results indicate that

  7. Using a morpho-functional approach to assess phytoplankton dynamics in two adjacent high-mountain lakes: a 10-year survey

    Directory of Open Access Journals (Sweden)

    Renata Trevisan

    2014-05-01

    Full Text Available Colbricon Superiore and Inferiore are two small adjacent high-mountain lakes located in the Paneveggio Natural Park (Italy. The lakes differ by size and depth while sharing the same bedrock setting and catchment basin. Changes in the phytoplankton communities were studied over a 10-years period to individuate which environmental variables would determine the main differences in biotic assemblages across time and between the two lakes.The study was conducted with fortnightly samplings, assessing the density and biomass of algal taxa. Relationships of each of the biological variables with water temperature, pH, conductivity, transparency, water level, previous week rainfall, and relative water column stability were analyzed by correlation and regression analyses, cluster analysis, and by canonical correspondence analysis. The most significant variables resulted air temperature, hydrologic water level and pH. The smaller Colbricon Inferiore had about double the amount of phytoplankton density and biomass than did the larger Colbricon Superiore. The same lake had higher diversity and lower evenness in structure of the phytoplankton community. Notwithstanding their proximity each lake appears to follow independent species composition dynamics, however parallel patterns were interestingly revealed when data were analyzed by pooling taxa into morpho-functional groups. Morpho-functional groups (MFGs 1b, 3a, 6b, 7a, 9b were differentially most abundant in warm periods, while 2c, 3b, 11c, 5e, 10a prevailed in cold years. MFGs 1b, 2d, 3a and 3b were more characteristic of Lake Colbricon Superiore, while Colbricon Inferiore preferentially featured MFGs 5a, 5e, 9a, 9b, 10a, 11a and 8a. The role of the meteo-climatic parameters was pointed out in driving the different patterns observed in the two lakes.

  8. Geophysical measures on a grassland of the high plateaus in the Vercors mountain (French Prealps): analysis of the local and regional hydroclimatic variations

    Science.gov (United States)

    Bigot, Sylvain; Rome, Sandra; Biron, Romain; Laurent, Jean-Paul; Lebel, Thierry; Dedieu, Jean-Pierre

    2010-05-01

    Territorial administrators (regional parks and reserves, forestry service, national and regional environnemental services) look for precise scientific elements to understand, prevent or mitigate the consequences of climate change on the ecosystem and on the socioeconomic activities of the French Prealps. They wish for example especially to improve the environmental mapping of ecologically sensitive areas related to agro-pastoral activities and the management of water ressources in the Vercors massif. Geophysical measures at a local scale should allow scientists to validate outputs of regional climate model which are still widely improvable in mountain context. This study present an original network of hydrometeorological measuring equipment installed on a grassland (named ‘Meadow of Darbounouse', 44°58'N - 5°28'E; about 0.8 km²) and located at 1300 m asl elevation on the high plateau of Vercors. This little stony basin (3,8 km of perimeter) surrounded by forested ridge lines and located into the Biological Reserve, represents at the same time a well known grazing land and a place of huge thermal amplitude (i.e. 32°C in summer). Hydropedological variations are there also significant for this karstic catchment area, modulated by summer droughts and possible partial flooding from spring melting snow. Since 2005, an automatic weather Campbell station was installed in the North of the basin, measuring rainfall, temperatures, wind and global radiation. In 2009 several meteorological data loggers (temperature and relative humidity) were installed in suburb of the basin. In complement 24 soil moisture sensors (10HS, Decagon Devices) were buried below the surface of the ground (5 and 15 cm) to measure the dielectric constant (i.e. the volumetric water content) at 6 representative places of the basin. Finally a groundwater data logger (OTT Orpheus Mini) based on a pressure probe and for the storage of water level and temperature was settled in the well situated in the

  9. Contrasting trends in floods for two sub-arctic catchments in northern Sweden - does glacier presence matter?

    Science.gov (United States)

    Dahlke, H. E.; Lyon, S. W.; Stedinger, J. R.; Rosqvist, G.; Jansson, P.

    2012-07-01

    Our understanding is limited to how transient changes in glacier response to climate warming will influence the catchment hydrology in the Arctic and Sub-Arctic. This understanding is particularly incomplete for flooding extremes because understanding the frequency of such unusual events requires long records of observation not often available for the Arctic and Sub-Arctic. This study presents a statistical analysis of trends in the magnitude and timing of flood extremes and the mean summer discharge in two sub-arctic catchments, Tarfala and Abisko, in northern Sweden. The catchments have different glacier covers (30% and 1%, respectively). Statistically significant trends (at the 5% level) were identified for both catchments on an annual and on a seasonal scale (3-months averages) using the Mann-Kendall trend test. Stationarity of flood records was tested by analyzing trends in the flood quantiles, using generalized least squares regression. Hydrologic trends were related to observed changes in the precipitation and air temperature, and were correlated with 3-months averaged climate pattern indices (e.g. North Atlantic oscillation). Both catchments showed a statistically significant increase in the annual mean air temperature over the comparison time period of 1985-2009 (Tarfala and Abisko pflood peaks and the mean summer discharge. Hydrologic trends indicated an amplification of the streamflow and flood response in the highly glacierized catchment and a dampening of the response in the non-glacierized catchment. The glacierized mountain catchment showed a statistically significant increasing trend in the flood magnitudes (p = 0.04) that is clearly correlated to the occurrence of extreme precipitation events. It also showed a significant increase in mean summer discharge (p = 0.0002), which is significantly correlated to the decrease in glacier mass balance and the increase in air temperature (p = 0.08). Conversely, the non-glacierized catchment showed a

  10. Analysis of the Course and Frequency of High Water Stages in Selected Catchments of the Upper Vistula Basin in the South of Poland

    Directory of Open Access Journals (Sweden)

    Andrzej Walega

    2016-09-01

    Full Text Available The paper presents an analysis of the course and frequency of high water stages in selected catchments of the upper Vistula basin in the south of Poland. The following rivers were investigated: the Dunajec–Nowy Targ-Kowaniec cross-section, the Rudawa–Balice cross-section, the Kamienica–Nowy Sącz cross-section, the Wisłok–Tryńcza cross-section and the San–Przemyśl cross-section. Daily flows from the years 1983–2014 were used to determine maximum annual flows and maximum flows per summer and winter half-year. Selected floods were analyzed with reference to the following metrics: POTX (mean size of the flow determined based on high water stages exceeding the assumed threshold value, POT3F (number of high water stages exceeding the threshold value for each hydrological year, WPOT3F (number of high water stages exceeding the threshold value for the winter half-year and, LOPT3F (number of high water stages exceeding the threshold value for the summer half-year. The determined metrics were analyzed for trend (Mann-Kendall test, homogeneity (Kruskal-Wallis test, and heteroscedasticity (Levene test. Additionally, periodograms were used to determine periodicity of time series for maximum annual flows. The resulting computations indicated upward trends in the analyzed flood metrics but they were not significant in any case. Therefore, in the years 1983–2014 no factors were observed that would significantly affect the size and frequency of high water runoff from the investigated catchments.

  11. Fire and high-elevation, five-needle pine (Pinus aristata & P. flexilis) ecosystems in the southern Rocky Mountains: What do we know?

    Science.gov (United States)

    Jonathan D. Coop; Anna W. Schoettle

    2011-01-01

    Rocky Mountain bristlecone pine (Pinus aristata Engelm) and limber pine (P. flexilis James) are high-elevation, fiveneedle pines of the southern Rocky Mountains. The pre-settlement role of fire in bristlecone and limber pine forests remains the subject of considerable uncertainty; both species likely experienced a wide range of fire regimes across gradients of site...

  12. Sediment flux dynamics as fingerprints of catchment rehabilitation: The case of western Rift Valley escarpment of northern Ethiopia

    Science.gov (United States)

    Asfaha, Tesfaalem G.; Frankl, Amaury; Haile, Mitiku; Zenebe, Amanuel; Nyssen, Jan

    2015-12-01

    Variability in supply and entrainment of stream bedload particles during storm events is an important hydrogeomorphologic response of steep mountain streams to land management in their catchments. Because of difficulties in its measurement and absence of accurate measuring equipment, bedload transport in mountain streams is, however, poorly understood. This study focuses on analyzing bedload supply and entrainment in 11 streams of sloping (27-65%) catchments (0.4-25 km2) in northern Ethiopia, which have experienced severe deforestation and degradation processes until the first half of the 1980s and considerable rehabilitation thereafter. Field measurements of the median diameter of the 10 coarsest bedload particles (Max10) moved in each event (n = 332) and stream bed particle sampling were carried out in three rainy seasons (2012-2014). Event peak discharges were calculated from daily measurements by 11 crest stage gauges using Manning's equation. Percentages of land cover classes in the catchments were detected from high resolution (0.6 m) Google Earth imagery (1 February, 2014). Morphometric characteristics of the catchments were computed from an ASTER digital elevation model and topographic maps. Hydraulic competence analysis for entrainment of the average Max10 was carried out using peak discharge, stream power, and critical shear stress approaches. The supply of Max10 was positively related to scar density on the surrounding slopes (R2 = 0.50, p < 0.05) and catchment area (R2 = 0.36, p < 0.05) while negatively related with total forest cover (R2 = 0.63, p < 0.05) or vegetation cover (R2 = 0.58, p < 0.05). A multiple regression analysis showed that 98% of the variability in Max10 is explained by scar density and catchment area. Entrainment of Max10 was positively related to peak discharge (Qp) (R2 = 0.60, p < 0.01), stream power (Ω) (R2 = 0.71, p < 0.01), Strickler's roughness (Sn) (R2 = 0.86, p < 0.01), and critical shear stress (τc) with reference to D50 (r

  13. Glacier evolution in high-mountain Asia under stratospheric sulfate aerosol injection geoengineering

    Directory of Open Access Journals (Sweden)

    L. Zhao

    2017-06-01

    Full Text Available Geoengineering by stratospheric sulfate aerosol injection may help preserve mountain glaciers by reducing summer temperatures. We examine this hypothesis for the glaciers in high-mountain Asia using a glacier mass balance model driven by climate simulations from the Geoengineering Model Intercomparison Project (GeoMIP. The G3 and G4 schemes specify use of stratospheric sulfate aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP 4.5 scenario for the 50 years between 2020 and 2069, and for a further 20 years after termination of geoengineering. We estimate and compare glacier volume loss for every glacier in the region using a glacier model based on surface mass balance parameterization under climate projections from three Earth system models under G3, five models under G4, and six models under RCP4.5 and RCP8.5. The ensemble projections suggest that glacier shrinkage over the period 2010–2069 is equivalent to sea-level rise of 9.0 ± 1.6 mm (G3, 9.8 ± 4.3 mm (G4, 15.5 ± 2.3 mm (RCP4.5, and 18.5 ± 1.7 mm (RCP8.5. Although G3 keeps the average temperature from increasing in the geoengineering period, G3 only slows glacier shrinkage by about 50 % relative to losses from RCP8.5. Approximately 72 % of glaciated area remains at 2069 under G3, as compared with about 30 % for RCP8.5. The widely reported reduction in mean precipitation expected for solar geoengineering is unlikely to be as important as the temperature-driven shift from solid to liquid precipitation for forcing Himalayan glacier change. The termination of geoengineering at 2069 under G3 leads to temperature rise of about 1.3 °C over the period 2070–2089 relative to the period 2050-2069 and corresponding increase in annual mean glacier volume loss rate from 0.17 to 1.1 % yr−1, which is higher than the 0.66 % yr−1 under RCP8.5 during 2070–2089.

  14. Robust Adaptation Research in High Mountains: Integrating the Scientific, Social, and Ecological Dimensions of Glacio-Hydrological Change

    Directory of Open Access Journals (Sweden)

    Graham McDowell

    2017-09-01

    Full Text Available Climate-related changes in glacierized watersheds are widely documented, stimulating adaptive responses among the 370 million people living in glacier-influenced watersheds as well as aquatic and riparian ecosystems. The situation denotes important interdependencies between science, society, and ecosystems, yet integrative approaches to the study of adaptation to such changes remain scarce in both the mountain- and non-mountain-focused adaptation scholarship. Using the example of glacio-hydrological change, it is argued here that this analytical limitation impedes the identification, development, and implementation of “successful” adaptations. In response, the paper introduces three guiding principles for robust adaptation research in glaciated mountain regions. Principle 1: Adaptation research should integrate detailed analyses of watershed-specific glaciological and hydro-meteorological conditions; glacio-hydrological changes are context-specific and therefore cannot be assumed to follow idealized trajectories of “peak water”. Principle 2: Adaptation research should consider the complex interplay between glacio-hydrological changes and socio-economic, cultural, and political conditions; responses to environmental changes are non-deterministic and therefore not deducible from hydrological changes alone. Principle 3: Adaptation research should be attentive to interdependencies, feedbacks, and tradeoffs between human and ecological responses to glacio-hydrological change; research that does not evaluate these socio-ecological dynamics may lead to maladaptive adaptation plans. These principles call attention to the linked scientific, social, and ecological dimensions of adaptation, and offer a point of departure for future climate change adaptation research in high mountains.

  15. Atmospheric deposition and lake chemistry trends at a high mountain site in the eastern Alps

    Directory of Open Access Journals (Sweden)

    Bertha THALER

    2000-02-01

    Full Text Available Records of atmospheric precipitation chemistry starting in 1983 and a series of limnological investigations at two high mountain reference lakes starting in 1988 enable us to describe the response of lake water chemistry to changes in precipitation chemistry and climate. The lakes are located at an altitude well above the timberline in a watershed composed of acidic rocks. Despite the observed reduction in the sulphur atmospheric deposition, the reference lakes showed no corresponding decline in sulphate concentrations, but a marked increase in the acid neutralising capacity was apparent. Changes of the seasonal distribution pattern of the precipitation amounts and a general increase of the air temperature have likely produced an increased weathering which increased the concentration of many inlake solutes and drove the lakes toward more buffered conditions. This phenomenon superimposed to changes like other physical factors (radiation, nutritional conditions and biological factors (enhanced production, competition, predation has produced in the last years greater modifications than merely those to be expected from the decreased acidic input.

  16. SCaMF–RM: A Fused High-Resolution Land Cover Product of the Rocky Mountains

    Directory of Open Access Journals (Sweden)

    Nicolás Rodríguez-Jeangros

    2017-09-01

    Full Text Available Land cover (LC products, derived primarily from satellite spectral imagery, are essential inputs for environmental studies because LC is a critical driver of processes involved in hydrology, ecology, and climatology, among others. However, existing LC products each have different temporal and spatial resolutions and different LC classes that rarely provide the detail required by these studies. Using multiple existing LC products, we implement our Spatiotemporal Categorical Map Fusion (SCaMF methodology over a large region of the Rocky Mountains (RM, encompassing sections of six states, to create a new LC product, SCaMF–RM. To do this, we must adapt SCaMF to address the prediction of LC in large space–time regions that present nonstationarities, and we add more flexibility in the LC classifications of the predicted product. SCaMF–RM is produced at two high spatial resolutions, 30 and 50 m, and a yearly frequency for the 30-year period 1983–2012. When multiple products are available in time, we illustrate how SCaMF–RM captures relevant information from the different LC products and improves upon flaws observed in other products. Future work needed includes an exhaustive validation not only of SCaMF–RM but also of all input LC products.

  17. SCaMF–RM: A Fused High-Resolution Land Cover Product of the Rocky Mountains

    KAUST Repository

    Rodríguez-Jeangros, Nicolás

    2017-10-02

    Land cover (LC) products, derived primarily from satellite spectral imagery, are essential inputs for environmental studies because LC is a critical driver of processes involved in hydrology, ecology, and climatology, among others. However, existing LC products each have different temporal and spatial resolutions and different LC classes that rarely provide the detail required by these studies. Using multiple existing LC products, we implement our Spatiotemporal Categorical Map Fusion (SCaMF) methodology over a large region of the Rocky Mountains (RM), encompassing sections of six states, to create a new LC product, SCaMF–RM. To do this, we must adapt SCaMF to address the prediction of LC in large space–time regions that present nonstationarities, and we add more flexibility in the LC classifications of the predicted product. SCaMF–RM is produced at two high spatial resolutions, 30 and 50 m, and a yearly frequency for the 30-year period 1983–2012. When multiple products are available in time, we illustrate how SCaMF–RM captures relevant information from the different LC products and improves upon flaws observed in other products. Future work needed includes an exhaustive validation not only of SCaMF–RM but also of all input LC products.

  18. Different pioneer plant species select specific rhizosphere bacterial communities in a high mountain environment.

    Science.gov (United States)

    Ciccazzo, Sonia; Esposito, Alfonso; Rolli, Eleonora; Zerbe, Stefan; Daffonchio, Daniele; Brusetti, Lorenzo

    2014-01-01

    The rhizobacterial communities of 29 pioneer plants belonging to 12 species were investigated in an alpine ecosystem to assess if plants from different species could select for specific rhizobacterial communities. Rhizospheres and unvegetated soils were collected from a floristic pioneer stage plot at 2,400 m a.s.l. in the forefield of Weisskugel Glacier (Matsch Valley, South Tyrol, Italy), after 160 years of glacier retreat. To allow for a culture-independent perspective, total environmental DNA was extracted from both rhizosphere and bare soil samples and analyzed by Automated Ribosomal Intergenic Spacer Analysis (ARISA) and Denaturing Gradient Gel Electrophoresis (DGGE). ARISA fingerprinting showed that rhizobacterial genetic structure was extremely different from bare soil bacterial communities while rhizobacterial communities clustered strictly together according to the plant species. Sequencing of DGGE bands showed that rhizobacterial communities were mainly composed of Acidobacteria and Proteobacteria whereas bare soil was colonized by Acidobacteria and Clostridia. UniFrac significance calculated on DGGE results confirmed the rhizosphere effect exerted by the 12 species and showed different bacterial communities (P < 0.05) associated with all the plant species. These results pointed out that specific rhizobacterial communities were selected by pioneer plants of different species in a high mountain ecosystem characterized by oligotrophic and harsh environmental conditions, during an early primary succession.

  19. High resolution stratigraphy of the Devonian-Carboniferous transitional beds in the Rhenish Mountains

    Directory of Open Access Journals (Sweden)

    D. Korn

    2003-01-01

    Full Text Available The Devonian-Carboniferous Boundary sections at Hasselbachtal, Oese, Apricke, and Ober-Rödinghausen, all located at the northern margin of the Rhenish Mountains, were measured in detail. A semi-quantitative evaluation of the carbonate content and resulting carbonate curves permitted a highly exact correlation of these sections. This result is supported by data on ammonoid records and volcanoclastic horizons. Carbonate fluctuations within the Hangenberg Limestone are regarded as showing a 100000 years cyclicity. A new ammonoid genus Hasselbachia n. gen. and the species Paprothites ruzhencevi n. sp. are described. Among the rugose corals, a new species Hillaxon hassel n. sp., is erected. Die Devon/Karbon-Grenzprofile Hasselbachtal, Oese, Apricke und Ober-Rödinghausen, alle auf der Nordflanke des Remscheid-Altenaer Sattels gelegen, wurden detailliert aufgenommen. Die halbquantitative Ermittlung des Karbonatgehaltes und daraus resultierenden Karbonatkurven eignen sich für eine sehr genaue Korrelation dieser Profile, die durch Funde von Ammonoideen sowie durch vulkanoklastische Horizonte unterstützt wird. Wechsel im Karbonatgehalt werden als 100000 Jahres-Zyklizität gedeutet. Die neue Ammonoideen-Gattung Hasselbachia n. gen. sowie die Art Paprothites ruzhencevi n. sp. werden beschrieben. Unter den rugosen Korallen wird die neue Art Hillaxon hassel n. sp. errrichtet. doi:10.1002/mmng.20030060105

  20. Thermoregulation and activity pattern of the high-mountain lizard Phymaturus palluma (Tropiduridae in Chile

    Directory of Open Access Journals (Sweden)

    Marcela A. Vidal

    2010-02-01

    Full Text Available Behavioral and physiological mechanisms of thermoregulation in ectotherms are conditioned by thermal constraints. These mechanisms may be even more restrictive when environmental conditions are unfavorable for individuals, especially when sexual dimorphism segregates the sexes spatially. In order to understand behavioral and physiological regulation mechanisms, we investigated the thermal biology of Phymaturus palluma (Molina, 1782, a sexually size dimorphic, high-mountain lizard that inhabits extreme climatic conditions. P. palluma showed a bimodal activity pattern, a major peak in the morning (11:00-13:30h and in the afternoon (15:30-18:00 h. The lizards were more active when substrate temperatures were between 25 and 28º C. The highest abundance was found around 27º C (between 11:00-12:30. Females showed greater activity than males in the early morning. Sub-adults and juveniles did not show differences in their activity pattern. There was a positive relationship between body temperature and air and substrate temperatures, suggesting typically thigmothermal regulation.

  1. The compositions of minerals within high pressure tectonic blocks from Horse Mountain, Northern California

    Energy Technology Data Exchange (ETDEWEB)

    Gilliam, C.E. (Mount Holyoke College, South Hadley, MA (United States). Geology Dept.)

    1993-03-01

    High pressure metamorphic blocks occur within serpentinite between the South Fork Mountain Schist and the Coast Range Fault, Humboldt Co., Northern California. Samples from three of these blocks were studied by petrographic techniques and quantitatively analyzed using the energy dispersive spectrometer on out scanning electron microscope. The mineral assemblages for three samples are as follows: WC86-7-3 contains omphacite (jd53, di36, hd11), pumpellyite, and relic igneous clinopyroxene. WC86-9-3 contains titanite, epidote chlorite, pumpellyite, and relic clinopyroxene. WC86-18-3 contains garnet, lawsonite, glaucophane, albite, chlorite, pumpellyite, minor quartz, and relic clinopyroxene. All samples contain relic clinopyroxene that, in the case of SC86-7-3, acts as a nucleus for omphacite growth. When present in cross cutting veins, omphacite has both radiating fibrous and blocky textures. Some epidote, titanite, clinopyroxene and pumpellyite were too fine to identify optically as well, but occur in the ground mass. Large grains of euhedral glaucophane, (Na[sub 2.0] Ca[sub .2])(Mg[sub 1.3] Fe[sub 2.0] Al[sub 1.7])Si[sub 8.0] O[sub 22] (OH)[sub 2], and garnet, (alm 33, pyO, sp30, gr37), containing relic ( ) clinopyroxene, glaucophane, and albite inclusions, were present in WC86-18-3. The high SiO[sub 2] and low TiO[sub 2] relative to Al[sub 2]O[sub 3] in relic clinopyroxene indicates a non-alkaline tholeiitic protolith. Omphacite compositions correspond to the type IV blueschist typical of the Franciscan Complex and constrain the pressures of metamorphism to be approximately 9 kb while lawsonite in WC86-18-3 implies a temperature below 450C. These observations indicate that the blocks are derived from subducted material that underwent metamorphism in a low temperature, high pressure setting. The process of their exhumation remains a mystery.

  2. The characteristics of weakly forced mountain-to-plain precipitation systems based on radar observations and high-resolution reanalysis

    Science.gov (United States)

    Xiao, Xian; Sun, Juanzhen; Chen, Mingxuan; Qie, Xiushu; Wang, Yingchun; Ying, Zhuming

    2017-03-01

    The metropolis of Beijing in China is located on a plain adjacent to high mountains to its northwest and the gulf of the Bohai Sea to its southeast. One of the most challenging forecast problems for Beijing is to predict whether thunderstorms initiating over the mountains will propagate to the adjacent plains and intensify. In this study, 18 warm season convective cases between 2008 and 2013 initiating on the mountains and intensifying on the plains under weak synoptic forcing were analyzed to gain an understanding of their characteristics. The statistical analysis was based on mosaic reflectivity data from six operational Doppler radars and reanalysis data produced by the Four-Dimensional Variational Doppler Radar Analysis System (VDRAS). The analysis of the radar reflectivity data shows that convective precipitation strengthened on the plains at certain preferred locations. To investigate the environmental conditions favoring the strengthening of the mountain-to-plain convective systems, statistical diagnoses of the rapid-update (12 min) 3 km reanalyses from VDRAS for the 18 cases were performed by computing the horizontal and temporal means of convective available potential energy, convective inhibition, vertical wind shear, and low-level wind for the plain and mountain regions separately. The results were compared with those from a baseline representing the warm season average and from a set of null cases and found considerable differences in these fields between the three data sets. The mean distributions of VDRAS reanalysis fields were also examined. The results suggest that the convergence between the low-level outflows associated with cold pools and the south-southeasterly environmental flows corresponds well with the preferred locations of convective intensification on the plains.

  3. The use of the linear reservoir concept to quantify the impact of changes in land use on the hydrology of catchments in the Andes

    Directory of Open Access Journals (Sweden)

    W. Buytaert

    2004-01-01

    Full Text Available The high Andes region of South Ecuador (The Páramo is characterised by a cold and wet climate. Most soils of the Páramo region are Andosols and Histosols, with a very high water retention capacity that is affected irreversibly by drying. This key property of Páramo soils buffers catchment outflow, resulting in an almost uniform outflow pattern which, notwithstanding the variability in rainfall, can be very variable in space and time. These soils serve as the most important reservoir of drinking and irrigation water for the densely populated inter-Andean depression region. The Páramo has long served only as an extensive grazing area but recent population pressure and land scarcity have increased cultivation. Two small Páramo catchments (about 2 km2 were monitored intensively for precipitation and discharge for over a year to assess the effect of such land-use changes on the hydrological properties. One catchment is in an undisturbed area and grazed intensively while in the other, local farmers started intensive drainage for cultivation of potatoes about five years ago. The linear reservoir concept has been used to assess the overall retention capacity of the catchments in terms of both peak response and base flow. In this model, every catchment is considered as a series of independent parallel reservoirs, each characterised by mean residence times (T. In every catchment, three major mean residence times can be distinguished. In the undisturbed catchment, an immediate response, characterised by a T of 5.4 hours, is followed by a slower response with a T of 44.3 h. The base flow has a mean T value of 360 h. The response of the cultivated catchment is similar with T values of 3.6 h, 27.2 h and 175 h, respectively. As a result, in the disturbed catchment, water release is about 40% faster than in the undisturbed catchment, so that the base flow falls rapidly to lower levels. The linear reservoir model is a simple way of quantifying the impact of

  4. An approach to predict water quality in data-sparse catchments using hydrological catchment similarity

    Science.gov (United States)

    Pohle, Ina; Glendell, Miriam; Stutter, Marc I.; Helliwell, Rachel C.

    2017-04-01

    An understanding of catchment response to climate and land use change at a regional scale is necessary for the assessment of mitigation and adaptation options addressing diffuse nutrient pollution. It is well documented that the physicochemical properties of a river ecosystem respond to change in a non-linear fashion. This is particularly important when threshold water concentrations, relevant to national and EU legislation, are exceeded. Large scale (regional) model assessments required for regulatory purposes must represent the key processes and mechanisms that are more readily understood in catchments with water quantity and water quality data monitored at high spatial and temporal resolution. While daily discharge data are available for most catchments in Scotland, nitrate and phosphorus are mostly available on a monthly basis only, as typified by regulatory monitoring. However, high resolution (hourly to daily) water quantity and water quality data exist for a limited number of research catchments. To successfully implement adaptation measures across Scotland, an upscaling from data-rich to data-sparse catchments is required. In addition, the widespread availability of spatial datasets affecting hydrological and biogeochemical responses (e.g. soils, topography/geomorphology, land use, vegetation etc.) provide an opportunity to transfer predictions between data-rich and data-sparse areas by linking processes and responses to catchment attributes. Here, we develop a framework of catchment typologies as a prerequisite for transferring information from data-rich to data-sparse catchments by focusing on how hydrological catchment similarity can be used as an indicator of grouped behaviours in water quality response. As indicators of hydrological catchment similarity we use flow indices derived from observed discharge data across Scotland as well as hydrological model parameters. For the latter, we calibrated the lumped rainfall-runoff model TUWModel using multiple

  5. Multi-catchment rainfall-runoff simulation for extreme flood estimation

    Science.gov (United States)

    Paquet, Emmanuel

    2017-04-01

    The SCHADEX method (Paquet et al., 2013) is a reference method in France for the estimation of extreme flood for dam design. The method is based on a semi-continuous rainfall-runoff simulation process: hundreds of different rainy events, randomly drawn up to extreme values, are simulated independently in the hydrological conditions of each day when a rainy event has been actually observed. This allows generating an exhaustive set of crossings between precipitation and soil saturation hazards, and to build a complete distribution of flood discharges up to extreme quantiles. The hydrological model used within SCHADEX, the MORDOR model (Garçon, 1996), is a lumped model, which implies that hydrological processes, e.g. rainfall and soil saturation, are supposed to be homogeneous throughout the catchment. Snow processes are nevertheless represented in relation with altitude. This hypothesis of homogeneity is questionable especially as the size of the catchment increases, or in areas of highly contrasted climatology (like mountainous areas). Conversely, modeling the catchment with a fully distributed approach would cause different problems, in particular distributing the rainfall-runoff model parameters trough space, and within the SCHADEX stochastic framework, generating extreme rain fields with credible spatio-temporal features. An intermediate solution is presented here. It provides a better representation of the hydro-climatic diversity of the studied catchment (especially regarding flood processes) while keeping the SCHADEX simulation framework. It consists in dividing the catchment in several, more homogeneous sub-catchments. Rainfall-runoff models are parameterized individually for each of them, using local discharge data if available. A first SCHADEX simulation is done at the global scale, which allows assigning a probability to each simulated event, mainly based on the global areal rainfall drawn for the event (see Paquet el al., 2013 for details). Then the

  6. Flushing of distal hillslopes as an alternative source of stream dissolved organic carbon in a headwater catchment

    Science.gov (United States)

    Gannon, John P; Bailey, Scott W.; McGuire, Kevin J.; Shanley, James B.

    2015-01-01

    We investigated potential source areas of dissolved organic carbon (DOC) in headwater streams by examining DOC concentrations in lysimeter, shallow well, and stream water samples from a reference catchment at the Hubbard Brook Experimental Forest. These observations were then compared to high-frequency temporal variations in fluorescent dissolved organic matter (FDOM) at the catchment outlet and the predicted spatial extent of shallow groundwater in soils throughout the catchment. While near-stream soils are generally considered a DOC source in forested catchments, DOC concentrations in near-stream groundwater were low (mean = 2.4 mg/L, standard error = 0.6 mg/L), less than hillslope groundwater farther from the channel (mean = 5.7 mg/L, standard error = 0.4 mg/L). Furthermore, water tables in near-stream soils did not rise into the carbon-rich upper B or O horizons even during events. In contrast, soils below bedrock outcrops near channel heads where lateral soil formation processes dominate had much higher DOC concentrations. Soils immediately downslope of bedrock areas had thick eluvial horizons indicative of leaching of organic materials, Fe, and Al and had similarly high DOC concentrations in groundwater (mean = 14.5 mg/L, standard error = 0.8 mg/L). Flow from bedrock outcrops partially covered by organic soil horizons produced the highest groundwater DOC concentrations (mean = 20.0 mg/L, standard error = 4.6 mg/L) measured in the catchment. Correspondingly, stream water in channel heads sourced in part by shallow soils and bedrock outcrops had the highest stream DOC concentrations measured in the catchment. Variation in FDOM concentrations at the catchment outlet followed water table fluctuations in shallow to bedrock soils near channel heads. We show that shallow hillslope soils receiving runoff from organic matter-covered bedrock outcrops may be a major source of DOC in headwater catchments in forested mountainous regions

  7. Combined investigations on long-term hydrochemical monitoring and high frequency measurements in the Critical Zone from the Auradé catchment (SW, France)

    Science.gov (United States)

    Ponnou-Delaffon, Vivien; Probst, Anne; Payre-Suc, Virginie; Ferrant, Sylvain; Probst, Jean-Luc

    2017-04-01

    The Critical Zone (CZ) is now well identified as the land-atmosphere interface under the influence of many human pressures rendering up vulnerable for future generations. Although many investigations have been undergone over the last 30 years in the different compartments of the CZ, it remains important to understand the overall functioning of this area in a context of global change. A long-term hydrological and chemical monitoring was performed since 30 years for nitrates and discharge, and for 10 years for major elements at the stream outlet of a small agricultural carbonated catchment (Auradé site). This catchment is part of the observatories network OZCAR infrastructure and since 1992 it was a pilot for improving agricultural practices. Two time scales were investigated based on a discrete sampling during low water flow and hydrological events, and since 2006 on high frequency datas (every 10mn) for pH, conductivity, nitrate, temperature…using a multiparameter probe. The long-term trends indicated mostly a decreasing in nitrate, Ca and Mg concentrations namely and an increase in DOC, which can be related to the influence of the environmental practices (fertilizers inputs, vegetative filter strip etc..), but more recently to the changes in temperature and hydrological patterns (decreasing discharge and occurrence of rare but intensive events). The high frequency measurements on short-term events allowed: (i) to highlight the mechanisms involved in flux exportations (nycthemeral cycle for nitrates as ex.), (ii) to reconstruct the chemical patterns by correlating the parameters to major elements, and finally (iii) to have a better and more precise approach of the contribution of weathering and land use on the hydrochemical functioning of the CZ, particularly on the disturbance of carbon cycle by anthropogenic fingerprints.

  8. Estimation of different flow components in a high-altitude glaciated catchment (Dudh Koshi, Nepalese Himalaya) using a distributed glacio-hydrological model

    Science.gov (United States)

    Mimeau, Louise; Esteves, Michel; Wagnon, Patrick; Brun, Fanny; Condom, Thomas; Jacobi, Hans-Werner; Zin, Isabella

    2017-04-01

    In a context of climate change and of water demand growth, understanding the origin of water flows in the Upper Himalayas is a key issue to estimate the future water resource availability and to plan the future uses of water in downstream regions. One of the main issues in high elevated and glaciated catchments hydrology is the insufficient representation of the cryospheric processes that control the dynamics of ice and snow covered surfaces in distributed hydrological models. Model shortcomings and the lack of meteorological data associated to extreme topography can lead to large uncertainties that need to be quantified. Here we focus on an Upper Dudh Koshi sub-catchment in Nepal with an area of 150 km2 of which 26% was glaciated in 2015. The hydrological regime of this catchment is essentially driven by precipitation and glacier melt during the monsoon season from June to September. This study aims at estimating the contribution of rainfall, glacial and snow melt to the Khumbu River runoff, as well as their seasonal variability during the period [2012-2015]. The physically based glacio-hydrological model DHSVM-GDM (Distributed Hydrology Soil Vegetation Model - Glacier Dynamics Model) was forced with in-situ meteorological data to run simulations for a period of three years. To simulate snow and glacier processes, DHSVM-GDM uses an energy balance model with one ice and two snow layers. For the needs of the study, some parametrizations were adapted in order to take into account cryospheric processes that are not or only partially described in the standard version of DHSVM-GDM, such as snow aging and liquid water transfer through glaciers. The snow albedo representation has been modified to have a more accurate description of the snow pack dynamics. Daily MODIS satellite images were used to validate the simulation of snow albedo and snow cover area. Mass balances from local measurement on the Pokhalde and Changri Nup glaciers, as well as regional geodetic mass

  9. Radiative forcing by dust and black carbon in snow of High Mountain Asia: Implications for glaciers and water resources

    Science.gov (United States)

    Painter, Thomas; Qian, Yun

    2017-04-01

    Snow and ice of High Mountain Asia provide critical freshwater supply to over a billion people and provide climate influence through higher albedo and lower thermal conductivity. High Mountain Asia holds the greatest amount of ice outside of Earth's polar region and as such has great potential to contribute to sea level rise. Snow cover and glaciers have been in general negative trend across the Anthropocene, yet there are large uncertainties in the scale of that retreat, the magnitude of the resulting contribution to sea-level rise, and in particular the causes. Our overarching science goal is to better understand the physical processes that are driving changes in High Mountain Asia snow and ice. Here, we present analysis of our NASA remote sensing retrievals of radiative forcing by dust and black carbon in snow and ice from MODIS, VIIRS, and Landsat 8 in the study domain of the NASA High Mountain Asia program. We also evaluate the simulations of radiative forcing by impurities in snow from the Weather Research and Forecasting (WRF) model coupled with its chemistry component (Chem), the land surface scheme of the Community Land Model (CLM), and the snow, ice, and aerosol radiative transfer model SNICAR. The unique suite of remote sensing products are (1) the MODIS Snow Covered Area and Grain size (MODSCAG) from which we calculate fractional snow covered area and the spatial bulk surface snow grain size of that fractional cover, and (2) the MODIS Dust Radiative Forcing in Snow (MODDRFS) from which we calculate clear-sky radiative forcing by impurities in snow. The analysis will be cast in context of our understanding of at-surface radiative forcing by anomalies in greenhouse gases and give us insight into the controls on snow and glacier retreat.

  10. Morphology and biology of Cyclops scutifer Sars, 1863 in high mountain lakes of East Siberia (including Lake Amut)

    Science.gov (United States)

    Sheveleva, Natalya G.; Itigilova, Mydygma Ts.; Chananbaator, Ayushcuren

    2017-03-01

    Data on zooplankton from 13 high-mountain lakes of East Siberia have shown that the Holarctic copepod Cyclops scutifer Sars, 1863 dominates among crustaceans. In July, its abundance comprised 64%-98% of the total plankton fauna in the pelagial of these lakes, approximately 30% in the littoral zone and 10% in small northern thermokarst lakes. Biometric measurements and morphological descriptions based on scanning microscope images are supplemented by the data on its geographic distribution and phenology.

  11. Integrating Unmanned Aerial Vehicles and Terrestrial Structure from Motion Photogrammetry for Assessing High Mountain Glacier Change, Huaytapallana, Peru

    Science.gov (United States)

    Wigmore, O.; Mark, B. G.; Lagos, P.; Somers, L. D.; McKenzie, J. M.; Huh, K. I.; Hopkinson, C.; Baraer, M.; Crumley, R. L.

    2016-12-01

    Terrestrial photogrammetry has a long and successful history of application to glaciological research. However, traditional methods rely upon large and expensive metric cameras and detailed triangulation of in-scene points for derivation of terrain models and analysis of glacier change. Recent developments in computer vision, including the advent of Structure from Motion (SfM) algorithms and associated software packages have made it possible to use consumer grade digital cameras to produce highly precise digital elevation models. This has facilitated the rapid expansion of unmanned aerial vehicles (UAVs) for mapping purposes. However, without onboard RTK GNSS positions of the UAV, within scene survey-grade ground targets are required for accurate georectification. Gaining access to mountain glaciers for the installation and survey of ground targets is often labour intensive, hazardous and sometimes impossible. Compounding this are limitations of UAV flight within these confined and high elevation locations and reduced flight times that limit the total survey area. Luckily, these environments also present a highly suitable location for the application of terrestrial SfM photogrammetry; because; high moraines, cliffs and ridgelines provide excellent 'semi-nadir' viewing of the glacier surface; while steep mountain walls present a close to nadir view from an oblique angle. In this study we present a workflow and results from an integrated UAV and terrestrial SfM photogrammetry campaign at Huaytapallana glacier, Huancayo Peru. We combined terrestrial images taken from GNSS surveyed positions with oblique UAV imagery of the mountain face. From this data a centimetre resolution orthomosaic and a decimetre resolution DEM of the snow and ice covered mountain face and proglacial lake were generated, covering over 6km2. Accuracy of the surface was determined from comparison over ice free areas to 1m aerial LiDAR data collected in 2009. Changes in glacier volume were then

  12. Mountain medicin

    DEFF Research Database (Denmark)

    Bay, Bjørn; Hjuler, Kasper Fjellhaugen

    2016-01-01

    Travelling to high altitudes is an increasingly popular form of recreational holiday. Individual medical advice may be essential for certain groups of individuals such as patients with chronic disorders, pregnant women or children. This is the second part in a series of two articles on mountain...... medicine. The first part covered high-altitude physiology and medical aspects of objective alpine dangers and the increased exposure to ultraviolet radiation. This part covers altitude sickness, fluid balance, nutrition, and precautions for patients with pre-existing medical conditions, pregnant women...

  13. Examination of catchment areas for public transport

    DEFF Research Database (Denmark)

    Landex, Alex; Hansen, Stephen; Andersen, Jonas Lohmann Elkjær

    2006-01-01

    The paper presents a method to examine the catchment areas for stops in high quality public transport systems based on the street network in the examined area. This is achieved by implementing the Service Area functions from the ArcGIS extension Network Analyst. The method is compared to a more...... simple method using only the Euclidean distance from the examined stop and the paper describes the differences in detail-level of the results. Furthermore, the paper describes how the Service Area method can be used to examine increments in the catchment areas by adding extra entrances to stations...... or by making changes in the street network around the station. The paper also discusses the degree of realism in the used GIS networks and how it can affect the size of the catchment areas. It is concluded that the Service Area method improves the detail-level and accuracy in catchment area analyses...

  14. Hydrogeological studies in high mountains karst environment: the example of Picos de Europa (Spain)

    Science.gov (United States)

    Meléndez, Mónica; Ballesteros, Daniel; Jiménez-Sanchez, Montserrat; García-Sansegundo, Joaquín

    2015-04-01

    Karst aquifers are very vulnerable to contamination due their high infiltration coefficient, elevated hydraulic conductivity, high speed of circulation, and very low self-purification capacities. The functioning of that type of aquifer is quite complicated by the high heterogeneity and anisotropy of the karst and the presence of three different types of porosity. It is necessary to understand the functioning of a karst aquifer in order to protect and manage them properly. Therefore, it is necessary to develop working methods to establish the aquifer hydrodynamics, especially in high mountain areas with many methodological constrains (e. g. difficulty to access). The Picos de Europa karst aquifer, located in theNational Park of Picos de Europa (North Spain), presents a high environmental, geomorphological and hydrogeological value; it is included in the "Spanish geological contexts with global relevance" by the Law of Natural Heritage and Biodiversity of Spain, being considered as a Global Geosite by the Geological and Mining Institute of Spain. In addition, the karst massif is included in several figures of environmental protection, both at global and national levels. Hydrogeological and geomorphological research is developed together in this area under the GEOCAVE project (MAGRAMA-580/12 OAPN) and the "Investigación hidrogeológica en las masas de agua subterránea 012.014 Picos de Europa-Panes y 012.018 Alto Deva-Alto Cares. (IGME-73.3.00.41.00/2013)". The aim of this study is to characterize the hydrodynamics of the karst aquifer, considering the snow as an important component of the aquifer recharge. The proposed methodology includes the installation of an integrated pressure sensor and data logger for level and temperature measurement in two karst spring related to two groundwater bodies (GWB) with 86 and 14 km2 extension. The store of data to regular intervals with punctual values of discharge measures has provided, at least, an annual series of data in

  15. Formation of minor moraines in high-mountain environments independent of a primary climatic driver

    Science.gov (United States)

    Wyshnytzky, Cianna; Lukas, Sven

    2016-04-01

    Closely-spaced minor moraines allow observations of moraine formation and ice-marginal fluctuations on short timescales, helping to better understand glacier retreat and predict its geomorphological effects (e.g. Sharp, 1984; Boulton, 1986; Bradwell, 2004; Lukas, 2012). Some minor moraines can be classified as annual moraines given sufficient chronological control, which implies a seasonal climatic driver of minor ice-front fluctuations. This leads to annual moraines being utilised as very specific and short-term records of glacier fluctuations and climate change. However, such research is sparse in high-mountain settings (Hewitt, 1967; Ono, 1985; Beedle et al., 2009; Lukas, 2012). This study presents the detailed sedimentological results of minor moraines at two high-mountain settings in the Alps. Minor moraines at Schwarzensteinkees, Austria, formed as push moraines in two groups, separated by a flat area and sloping zone with scattered boulders and flutings. The existence of a former proglacial lake, evident from ground-penetrating radar surveys and geomorphological relationships, appears to have exerted the primary control on minor moraine formation. Minor moraines at Silvrettagletscher, Switzerland, exist primarily on reverse bedrock slopes. The presence of these bedrock slopes, and in some areas medial moraines emerging beyond the ice front, appear to exert the primary controls on minor moraine formation. These findings show that climate may only play a small role in minor moraine formation at these study sites, echoing similar findings from another glacier in the Alps (Lukas, 2012). These two glaciers and valleys are differentiated primarily by geometry, sedimentation, and mechanisms of minor moraine formation. Despite these crucial differences, valley geometry and pre-existing geomorphology play a large, if not dominant, role in minor moraine formation and are at odds with a primarily-climatic control of minor moraine formation in lowland settings. This

  16. [Biogeochemical cycles in natural forest and conifer plantations in the high mountains of Colombia].

    Science.gov (United States)

    León, Juan Diego; González, María Isabel; Gallardo, Juan Fernando

    2011-12-01

    Plant litter production and decomposition are two important processes in forest ecosystems, since they provide the main organic matter input to soil and regulate nutrient cycling. With the aim to study these processes, litterfall, standing litter and nutrient return were studied for three years in an oak forest (Quercus humboldtii), pine (Pinus patula) and cypress (Cupressus lusitanica) plantations, located in highlands of the Central Cordillera of Colombia. Evaluation methods included: fine litter collection at fortnightly intervals using litter traps; the litter layer samples at the end of each sampling year and chemical analyses of both litterfall and standing litter. Fine litter fall observed was similar in oak forest (7.5 Mg ha/y) and in pine (7.8 Mg ha/y), but very low in cypress (3.5 Mg ha/y). Litter standing was 1.76, 1.73 and 1.3 Mg ha/y in oak, pine and cypress, respectively. The mean residence time of the standing litter was of 3.3 years for cypress, 2.1 years for pine and 1.8 years for oak forests. In contrast, the total amount of retained elements (N, P, S, Ca, Mg, K, Cu, Fe, Mn and Zn) in the standing litter was higher in pine (115 kg/ha), followed by oak (78 kg/ha) and cypress (24 kg/ha). Oak forests showed the lowest mean residence time of nutrients and the highest nutrients return to the soil as a consequence of a faster decomposition. Thus, a higher nutrient supply to soils from oaks than from tree plantations, seems to be an ecological advantage for recovering and maintaining the main ecosystem functioning features, which needs to be taken into account in restoration programs in this highly degraded Andean mountains.

  17. Effects of Autumn and Spring Heat Waves on Seed Germination of High Mountain Plants.

    Directory of Open Access Journals (Sweden)

    Simone Orsenigo

    Full Text Available Alpine plants are considered to be particularly vulnerable to climate change and related extreme episodes, such as heat waves. Despite growing interest in the impact of heat waves on alpine plants, knowledge about their effects on regeneration is still fragmentary. Recruitment from seeds will be crucial for the successful migration and survival of these species and will play a key role in their future adaptation to climate change. In this study, we assessed the impacts of heat waves on the seed germination of 53 high mountain plants from the Northern Apennines (Italy. The seeds were exposed to laboratory simulations of three seasonal temperature treatments, derived from real data recorded at a meteorological station near the species growing site, which included two heat wave episodes that occurred both in spring 2003 and in autumn 2011. Moreover, to consider the effect of increasing drought conditions related to heat waves, seed germination was also investigated under four different water potentials. In the absence of heat waves, seed germination mainly occurred in spring, after seeds had experienced autumn and winter seasons. However, heat waves resulted in a significant increase of spring germination in c. 30% of the species and elicited autumn germination in 50%. When heat waves were coupled with drought, seed germination decreased in all species, but did not stop completely. Our results suggest that in the future, heat waves will affect the germination phenology of alpine plants, especially conditionally dormant and strictly cold-adapted chorotypes, by shifting the emergence time from spring to autumn and by increasing the proportion of emerged seedlings. The detrimental effects of heat waves on recruitment success is less likely to be due to the inhibition of seed germination per se, but rather due to seedling survival in seasons, and temperature and water conditions that they are not used to experiencing. Changes in the proportion and

  18. Climate change and socio-ecological transformation in high mountains: an empirical study of Garhwal Himalaya

    Directory of Open Access Journals (Sweden)

    Sati Vishwambhar Prasad

    2015-01-01

    Full Text Available Mountain regions are highly vulnerable to climate change, as they are ecologically fragile, tectonically and seismically active, and geologically sensitive. The main objectives of this study are to examine socio-ecological transformations and to illustrate the major driving forces - climate change, education and waves of modern civilization - in the Garhwal Himalaya. Data on socio-ecological systems and their patterns of change were accumulated from primary and secondary sources and through participatory rural appraisal. We present a case study where household level surveys were conducted in two villages. A total of 37 households were surveyed. Additionally, marginal farmers and extension workers were interviewed. Questions on population, migration, cropping pattern and livestock were answered by the head of the surveyed households. Population size was decreasing due to out-migration. The whole Garhwal region experienced 15.3% out-migration, while migration from the two villages was observed at 50% during the period 1990-2014. Similarly, changes in land use and cropping patterns and in the livestock population were observed. There was a decrease in the extent of land under cereals (24% and fruits (79%, a decrease in fruit production (75%, and a decrease in the number of livestock (76%. Climate change was observed as a major driver of the decrease in production and productivity of cereals and fruits, leading to land abandonment. Education, on the other hand, was a major driver of out-migration. Further, extreme events through climate change happened more frequently and changed the landscape. This study reveals that an increase in infrastructural facilities to create jobs and sustainable land management can control out-migration and can enhance land capability.

  19. Sediment transport and erosional processes of a mountain bedrock channel using high-resolution topographic surveys

    Science.gov (United States)

    Yin, Yu-Hsuan; Shyu, J. Bruce H.

    2017-04-01

    In recent years, spatial information with high resolution and accuracy have become widely available, thanks to the rapid technological developments. Such data have been applied in a variety of topics, including the digitization and monitoring of outcrops and the construction of digital elevation models (DEMs) of landscapes. In fluvial geomorphology, it is critical to understand the sediment transport and erosional processes of bedrock channels, but previously this is generally done using computer numerical simulations or minimized experiments. Therefore, this study intends to observe in situ fluvial sediment transport and erosional processes using terrestrial laser scanning (also called "ground LiDAR") and structure-from-motion (SfM) photogrammetry in a mountain bedrock channel in eastern Taiwan. Along the Swallow Grotto (Yanzikou) section of the Liwu River, there are many large boulders with different sizes that are up to more than ten meters. Most of these boulders came from rock fall events of a nearby tributary, and are gneiss in composition, distinctively different from the bedrock of the river channel (marble). Thus in this study, we chose these boulders as our survey targets. We applied ground LiDAR survey to observe the movement of the boulders, and to understand the transportation threshold of sediments under different flow conditions. For those giant boulders that do not seem to be moveable under regular fluvial conditions, we suspect that bedrock erosional processes apply to them. We then used SfM photogrammetry to monitor the erosion of particular boulders. By constructing 3D models of the boulders before and after flooding events, we will be able to analyze the amount and location of erosion occurred on the boulders. Combining these different datasets and results, we hope to further understand the sediment transport and erosional processes of bedrock channels.

  20. Effects of Autumn and Spring Heat Waves on Seed Germination of High Mountain Plants.

    Science.gov (United States)

    Orsenigo, Simone; Abeli, Thomas; Rossi, Graziano; Bonasoni, Paolo; Pasquaretta, Cristian; Gandini, Maurizia; Mondoni, Andrea

    2015-01-01

    Alpine plants are considered to be particularly vulnerable to climate change and related extreme episodes, such as heat waves. Despite growing interest in the impact of heat waves on alpine plants, knowledge about their effects on regeneration is still fragmentary. Recruitment from seeds will be crucial for the successful migration and survival of these species and will play a key role in their future adaptation to climate change. In this study, we assessed the impacts of heat waves on the seed germination of 53 high mountain plants from the Northern Apennines (Italy). The seeds were exposed to laboratory simulations of three seasonal temperature treatments, derived from real data recorded at a meteorological station near the species growing site, which included two heat wave episodes that occurred both in spring 2003 and in autumn 2011. Moreover, to consider the effect of increasing drought conditions related to heat waves, seed germination was also investigated under four different water potentials. In the absence of heat waves, seed germination mainly occurred in spring, after seeds had experienced autumn and winter seasons. However, heat waves resulted in a significant increase of spring germination in c. 30% of the species and elicited autumn germination in 50%. When heat waves were coupled with drought, seed germination decreased in all species, but did not stop completely. Our results suggest that in the future, heat waves will affect the germination phenology of alpine plants, especially conditionally dormant and strictly cold-adapted chorotypes, by shifting the emergence time from spring to autumn and by increasing the proportion of emerged seedlings. The detrimental effects of heat waves on recruitment success is less likely to be due to the inhibition of seed germination per se, but rather due to seedling survival in seasons, and temperature and water conditions that they are not used to experiencing. Changes in the proportion and timing of emergence

  1. Effects of Autumn and Spring Heat Waves on Seed Germination of High Mountain Plants

    Science.gov (United States)

    Orsenigo, Simone; Abeli, Thomas; Rossi, Graziano; Bonasoni, Paolo; Pasquaretta, Cristian; Gandini, Maurizia; Mondoni, Andrea

    2015-01-01

    Alpine plants are considered to be particularly vulnerable to climate change and related extreme episodes, such as heat waves. Despite growing interest in the impact of heat waves on alpine plants, knowledge about their effects on regeneration is still fragmentary. Recruitment from seeds will be crucial for the successful migration and survival of these species and will play a key role in their future adaptation to climate change. In this study, we assessed the impacts of heat waves on the seed germination of 53 high mountain plants from the Northern Apennines (Italy). The seeds were exposed to laboratory simulations of three seasonal temperature treatments, derived from real data recorded at a meteorological station near the species growing site, which included two heat wave episodes that occurred both in spring 2003 and in autumn 2011. Moreover, to consider the effect of increasing drought conditions related to heat waves, seed germination was also investigated under four different water potentials. In the absence of heat waves, seed germination mainly occurred in spring, after seeds had experienced autumn and winter seasons. However, heat waves resulted in a significant increase of spring germination in c. 30% of the species and elicited autumn germination in 50%. When heat waves were coupled with drought, seed germination decreased in all species, but did not stop completely. Our results suggest that in the future, heat waves will affect the germination phenology of alpine plants, especially conditionally dormant and strictly cold-adapted chorotypes, by shifting the emergence time from spring to autumn and by increasing the proportion of emerged seedlings. The detrimental effects of heat waves on recruitment success is less likely to be due to the inhibition of seed germination per se, but rather due to seedling survival in seasons, and temperature and water conditions that they are not used to experiencing. Changes in the proportion and timing of emergence

  2. Adaptation of iron transport and metabolism to acute high-altitude hypoxia in mountaineers

    NARCIS (Netherlands)

    Goetze, O.; Schmitt, J.; Spliethoff, K.; Theurl, I.; Weiss, G.; Swinkels, D.W.; Tjalsma, H.; Maggiorini, M.; Krayenbuhl, P.; Rau, M.; Fruehauf, H.; Wojtal, K.A.; Mullhaupt, B.; Fried, M.; Gassmann, M.; Lutz, T.; Geier, A.

    2013-01-01

    Human iron homeostasis is regulated by intestinal iron transport, hepatic hepcidin release, and signals from pathways that consume or supply iron. The aim of this study was to characterize the adaptation of iron homeostasis under hypoxia in mountaineers at the levels of (1) hepatic hepcidin release,

  3. Cascading effect of exotic fish fry on plankton community in a tropical Andean high mountain lake: a mesocosm experiment

    Directory of Open Access Journals (Sweden)

    Yimy Herrera-Martínez

    2017-01-01

    Full Text Available Fishless Andean high mountain lakes may be vulnerable to fish invasion because they tend to be small, oligotrophic and contain low zooplankton diversity. During the first decades of the twentieth century, rainbow trout, Oncorhynchus mikiss, was introduced in South America, and stocking of juvenile stages (fry in lakes continues today. However, their effect on plankton in these lakes has been little studied. We performed a mesocosms experiment to assess effects of trout of different ontogenetic stages on zooplankton and phytoplankton in a tropical-Andean high mountain lake. The presence of trout fry resulted in declines in several large zooplankton taxa, increases in chlorophyll a and dissolved inorganic nitrogen (DIN. Our results showed that small fry consume large copepods (Colombodiaptomus brandorffi at a faster rate than larger fry, and also consumed medium sized copepods (Tropocyclops prasinus that are not affected by the larger trout fry. Fish of both sizes consumed Ceriodaphnia quadrangula, a midsize cladoceran. Fish predation had weak effect on the phytoplankton biomass, but we found a correlation between zooplankton biomass and phytoplankton richness, and significantly larger cell of the alga Peridinium in the presence of fish. Our results indicate that trout introduction produces cascading ecological and phenotypic effects on the plankton communities of tropical mountain lakes, similar to those observed in temperate latitudes.

  4. High rates of energy expenditure and water flux in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea

    Science.gov (United States)

    Crocker, D.E.; Kofahl, N.; Fellers, G.D.; Gates, N.B.; Houser, D.S.

    2007-01-01

    We measured water flux and energy expenditure in free-ranging Point Reyes mountain beavers Aplodontia rufa phaea by using the doubly labeled water method. Previous laboratory investigations have suggested weak urinary concentrating ability, high rates of water flux, and low basal metabolic rates in this species. However, free-ranging measurements from hygric mammals are rare, and it is not known how these features interact in the environment. Rates of water flux (210 ?? 32 mL d-1) and field metabolic rates (1,488 ?? 486 kJ d-1) were 159% and 265%, respectively, of values predicted by allometric equations for similar-sized herbivores. Mountain beavers can likely meet their water needs through metabolic water production and preformed water in food and thus remain in water balance without access to free water. Arginine-vasopressin levels were strongly correlated with rates of water flux and plasma urea : creatinine ratios, suggesting an important role for this hormone in regulating urinary water loss in mountain beavers. High field metabolic rates may result from cool burrow temperatures that are well below lower critical temperatures measured in previous laboratory studies and suggest that thermoregulation costs may strongly influence field energetics and water flux in semifossorial mammals. ?? 2007 by The University of Chicago. All rights reserved.

  5. Response of native and exotic bark beetles to high-energy wind event in the Tian Shan Mountains, Kazakhstan

    Science.gov (United States)

    Mukhamadiev, N.; Lynch, A.; O'Connor, C.; Sagitov, A.; Panyushkina, I. P.

    2012-12-01

    On May 17, 2011, the spruce forest of Yile-Alatausky and Medeo National Parks in southeast Kazakhstan was surged by a high-energy cyclonic storm. Severe blowdown damaged several thousand hectare of Tian Shan spruce forest (Picea schrenkiana), with over 90% of trees killed in extensive areas. Bark beetle populations are increasing rapidly, particularly Ips hauseri, I. typographis, I. sexdentatus, and Pityogenes perfossus (all Coleoptera: Curculionidae). Little is known about the frequency or extent of either large storm events or bark beetle outbreaks in the Tian Shan Mountains, nor about associations between outbreaks of these species and temperature and precipitation regimes. Local managers are concerned that triggering bark beetle outbreaks during current unusually warm, dry conditions will have devastating consequences for the residual forest and forest outside of the blowdown. We characterize the bark beetle population response to the 2011 event to date, and reconstruct the temporal and spatial dynamics of historical disturbance events in the area using dendrochronology. Additionally temperature and precipitation-sensitive tree-ring width chronologies from the Tian Shan Mountains are analyzed to determine high- and low-frequency variability of climate for the past 200 years. Catastrophic windstorm disturbances may play a crucial role in determining forest structure across the mountains. We hypothesize that the Tian Shan spruce forest could be prone to severe storm winds and subsequent bark beetle outbreaks and never reach an old-growth phase between events.

  6. Molybdenum, vanadium, and uranium weathering in small mountainous rivers and rivers draining high-standing islands

    Science.gov (United States)

    Gardner, Christopher B.; Carey, Anne E.; Lyons, W. Berry; Goldsmith, Steven T.; McAdams, Brandon C.; Trierweiler, Annette M.

    2017-12-01

    Rivers draining high standing islands (HSIs) and small mountainous rivers (SMRs) are known to have extremely high sediment fluxes, and can also have high chemical weathering yields, which makes them potentially important contributors to the global riverine elemental flux to the ocean. This work reports on the riverine concentrations, ocean flux, and weathering yields of Molybdenum (Mo), Vanadium (V), and Uranium (U) in a large number of small but geochemically important rivers using 338 river samples from ten lithologically-diverse regions. These redox-sensitive elements are used extensively to infer paleo-redox conditions in the ocean, and Mo and V are also important rock-derived micronutrients used by microorganisms in nitrogen fixation. Unlike in large river systems, in which dissolved Mo has been attributed predominately to pyrite dissolution, Mo concentrations in these rivers did not correlate with sulfate concentrations. V was found to correlate strongly with Si in terrains dominated by silicate rocks, but this trend was not observed in primarily sedimentary regions. Many rivers exhibited much higher V/Si ratios than larger rivers, and rivers draining young Quaternary volcanic rocks in Nicaragua had much higher dissolved V concentrations (mean = 1306 nM) than previously-studied rivers. U concentrations were generally well below the global average with the exception of rivers draining primarily sedimentary lithologies containing carbonates and shales. Fluxes of U and Mo from igneous terrains of intermediate composition are lower than the global average, while fluxes of V from these regions are higher, and up to two orders of magnitude higher in the Nicaragua rivers. Weathering yields of Mo and V in most regions are above the global mean, despite lower than average concentrations measured in some of those systems, indicating that the chemical weathering of these elements are higher in these SMR watersheds than larger drainages. In regions of active boundaries

  7. ^{10}Be cosmogenic nuclide chronology of the latest Pleistocene glacial stages in the High Tatra Mountains

    Science.gov (United States)

    Opyrchał, Ewelina; Zasadni, Jerzy; Kłapyta, Piotr; Christl, Marcus; Ivy-Ochs, Susan

    2017-04-01

    During the Pleistocene glaciers readvanced several times, shaping the mountains and building the variety of landforms which can be used to reconstruct paleo-glaciers and better understand their response to climate changes as well as the influences from the local topography. The aim of this project is to investigate the timing and geometry of glacier advances during the final stages of the last glaciation in the Tatra Mountains. This study comprises detailed geomorphological mapping of landforms, absolute and relative dating, which were applied in the the Veľká Studená Valley, selected as a case study for the Tatra Mountains. The 10Be cosmogenic nuclide dating method was used to investigate the deglaciation history by dating the absolute time since the rock surface has been exposed by glacier. Surfaces selected for dating were also tested using the Schmidt-hammer tool to establish a relative chronology of landforms in the valley. In the highest parts of the mountains two well-developed systems of moraines and relict rock glaciers are present. The younger system can be attributed to glaciers activity during the Younger Dryas whereas the older one represents most likely pre-Bolling-Allerod glacier activity. Both systems are limited to the glacial cirque but are significantly different in their geometry, reconstructed direction of glacier advance and observed landform freshness. In addition, an analysis of snow persistence using Landsat imagery and a Normalized Differential Snow Index (NDSI) has been performed. Patterns obtained from NDSI reveal recent late-spring and early-summer snow patches and indicate sites prone to glacier inception, growth and readvance in accordance with the spatial extent of glaciers during their last activity in the investigated mountain range. This research was funded by the Polish National Science Centre (NCN) grant No. 2015/17/B/ST10/03127.

  8. Explaining the mechanisms through which regional atmospheric circulation variability drives summer temperatures and glacial melt in western High Mountain Asia (HMA)

    Science.gov (United States)

    Forsythe, Nathan; Fowler, Hayley; Blenkinsop, Stephen; Li, Xiaofeng; Pritchard, David

    2017-04-01

    Comprehension of mechanisms by which atmospheric circulation influences sub-regional temperature and water resources variability in high-elevation mountainous catchments is of great scientific urgency due to the dependency of large downstream populations on the river flows these basins provide. In this work we quantify a regional atmospheric pattern, the Karakoram Zonal Shear (KZS), with a very pronounced annual cycle which we standardise into a dimensionless (seasonal) circulation metric the Karakoram Zonal Index (KZI). Going beyond previous regional circulation metrics such as the "middle-upper tropospheric temperature index" (MUTTI) or the Webster and Yang Monsoonal Index (WYMI) which have focused solely on the South Asian Summer Monsoon (June to September) season, the KZS/KZI provides an indicator which captures the influence and interactions of the westerly jet throughout the entire annual cycle. Use of the KZS and KZI have led us to identify a further regional atmospheric system, the Karakoram Vortex, which propagates "warm high" (anticyclonic postitive temperature anomaly) and "cold low" (cyclonic negative temperature anomaly) patterns across a very broad swath of Central and South Asia in winter but over a much more constrained area of western HMA in summer. The KV exerts this temperature influence through a combination of adiabatic effects and large-scale advection. Quantify KV influence, the KZI shows strong and statistically significantly near surface (2m) air temperatures both across western HMA both as observed through local meteorological stations and as estimated by an ensemble of global meteorological reanalyses. We show that this strong influence on temperature translates to important consequences for meltwater generation from highly glaciated Indus river tributaries which is logical given that previous studies have established the role of air temperature in modulating glacially-derived river flows in western HMA. By improving the understanding of

  9. Characterisation of acid mine drainage in a high rainfall mountain environment, New Zealand.

    Science.gov (United States)

    Davies, Hugh; Weber, Paul; Lindsay, Phil; Craw, Dave; Pope, James

    2011-07-01

    The Stockton coal mine lies at 700-1100 m above sea level in a mountainous orographic precipitation zone on the West Coast of the South Island of New Zealand. Rainfall exceeds 6000 mm/year and arrives with frequent flood events that can deliver > 200 mm/day. Streams vary in discharges by up to two orders of magnitude over a time scale of hours. Pyritic waste rock at the mine interacts chemically with even the most intense rainfall, and almost all runoff is acidic to some degree. In the most intense rain event recorded in this study (> 10 mm/hour), dilution of acid mine drainage (AMD) occurred and pH rose from 3 to >5 over several hours, with stream discharge at a monitoring point rising from 100 cumecs. However, most rain events of similar magnitude are less intense, longer duration, and only raise AMD pH to ~4 with similar high discharges. Results presented here for Stockton confirm that it is the intensity of rain events on the hourly scale, rather than the total amount of rainwater delivered to the site, that governs the amount and composition of AMD generated during flood events. Stream discharge loads of dissolved iron and aluminium range from ~20 to 1000 kg/hour. Dissolved sulfate and acidity loads are typically ~500 kg/hour but can exceed 20 tonnes/hour in rain events. First flush effects observable elsewhere around the world involving peak metal loads following dry periods or seasonal changes are not obvious at Stockton due to the high and variable rainfall environment. Dissolved Fe concentrations may be limited in runoff waters by precipitation of jarosite and schwertmannite, especially when rainfall is sufficiently intense to raise pH to 4 or higher. These minerals are widespread in the exposed waste rock on site. Likewise, precipitation of alunite may occur as pH rises in rain events, but no field evidence for this has been observed. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. A vegetation description and floristic analyses of the springs on the Kammanassie Mountain, Western Cape

    Directory of Open Access Journals (Sweden)

    G. Cleaver

    2004-12-01

    Full Text Available The Kammanassie Mountain is a declared mountain catchment area and a Cape mountain zebra Equus zebra zebra population is preserved on the mountain. The high number of springs on the mountain not only provides water for the animal species but also contributes to overall ecosystem functioning. Long-term conservation of viable ecosystems requires a broader understanding of the ecological processes involved. It was therefore decided that a classification, description and mapping of the spring vegetation of the Kammanassie Mountain be undertaken. A TWINSPAN classification, refined by Braun-Blanquet procedures, revealed 11 major plant communities that could be related to geological origin. Habitat factors associated with differences in vegetation include topography, soil type and grazing. Descriptions of the plant communities include diagnostic species as well as prominent and less conspicuous species of the tree, shrub and herbaceous layers. The results also indicate a high species richness compared to similar regions and the difference between plant communities of wet and dry springs. This data is important for long-term monitoring of the spring ecosystems as well as for the compilation of management plans.

  11. Ozone causes needle injury and tree decline in Pinus hartwegii at high altitudes in the mountains around Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    de la l. Bauere, M.deL.; Tejeda, T.H.; Manning, W.J.

    1985-08-01

    Needles of P. hartwegii were examined for a two-year period at 22 plots at Ajusco, D.F., south of Mexico City, at 3000 m. Ozone injury symptoms, consisting of extensive yellow banding and mottling, were observed on mature needles. These also became evident on new needles as they matured. This resulted in premature needle loss, reduction in cone and seed production, loss of tree vigor, bark beetle infestations, and tree decline and death. P. montezumae var. lindleyi and a few P. hartwegii trees in the same area were less susceptible. The most severe ozone injury to P. hartwegii occurs west to southwest of Mexico City in the mountain forest reserve of Desierto de los Leones, at 3500 m. Based on observations, the authors feel that needle injury and decline of P. hartwegii at high elevations in the mountains around Mexico City is caused primarily by ozone and not acid rain. It resembles the ozone-caused decline of ponderosa pine in the San Bernardino Mountains in California.

  12. Joint interpretation of seismic tomography and new magnetotelluric results provide evidence for support of high topography in the Southern Rocky Mountains and High Plains of eastern Colorado, USA

    Science.gov (United States)

    Feucht, D. W.; Sheehan, A. F.; Bedrosian, P.

    2015-12-01

    A recent magnetotelluric (MT) survey in central Colorado, USA, when interpreted alongside existing seismic tomography, reveals potential mechanisms of support for high topography both regionally and locally. Broadband and long period magnetotelluric data were collected at twenty-three sites along a 330 km E-W profile across the Southern Rocky Mountains and High Plains of central North America as part of the Deep RIFT Electrical Resistivity (DRIFTER) experiment. Remote-reference data processing yielded high quality MT data over a period range of 100 Hz to 10,000 seconds. A prominent feature of the regional geo-electric structure is the Denver Basin, which contains a thick package of highly conductive shales and porous sandstone aquifers. One-dimensional forward modeling was performed on stations within the Denver Basin to estimate depth to the base of this shallow conductor. Those estimates were then used to place a horizontal penalty cut in the model mesh of a regularized two-dimensional inversion. Two-dimensional modeling of the resistivity structure reveals two major anomalous regions in the lithosphere: 1) a high conductivity region in the crust under the tallest peaks of the Rocky Mountains and 2) a lateral step increase in lithospheric resistivity beneath the plains. The Rocky Mountain crustal anomaly coincides with low seismic wave speeds and enhanced heat flow and is thus interpreted as evidence of partial melt and/or high temperature fluids emplaced in the crust by tectonic activity along the Rio Grande Rift. The lateral variation in the mantle lithosphere, while co-located with a pronounced step increase in seismic velocity, appears to be a gradational boundary in resistivity across eastern Colorado and could indicate a small degree of compositional modification at the edge of the North American craton. These inferred conductivity mechanisms, namely crustal melt and modification of mantle lithosphere, likely contribute to high topography locally in the

  13. Non-free ionic transport of sodium, magnesium, and calcium in streams of two adjacent headwater catchments with different vegetation types in Japan

    Science.gov (United States)

    Terajima, Tomomi; Moriizumi, Mihoko; Nakamura, Tomohiro

    2017-01-01

    Sodium (Na), magnesium (Mg), calcium (Ca) are usually believed to occur mostly as free ions in the fresh water and consequently little is known about their chemical species. To understand the importance of non-free ionic fractions (NIF) of major metals in freshwater streams, Na, Mg, Ca, silicon (Si), and fulvic acid-like materials (FAM) were measured in streams of mountainous adjacent headwater catchments dominated by different vegetation types (planted evergreen coniferous forest and natural deciduous broadleaf forest). During both no rainfall periods and rainstorms, the proportion of NIF relative to total elements was lower in the coniferous catchment than in the deciduous catchment, although it sometimes accounted for half or more of the total concentrations of Na, Mg, and Ca in both catchments. The solubility of metal compounds was higher than the measured maximum concentrations of Na+, Mg2+, and Ca2+ to the extent that inorganic bonding was hardly possible. During no rainfall periods when FAM was slightly produced into the streams, the fluxes of NIF and Si were highly correlated (r > 0.92, p NIF correlated weakly with that of Si but did not correlate with that of FAM in both catchments. In contrast, during a heavy rainstorm, the flux of NIF correlated strongly (r ⩾ 0.83, p NIF originated in the quick-flow component (i.e., surface or near-surface water) in stream water (ΔNIF) correlated strongly (r ⩾ 0.81, p < 0.0001, n = 22) with that of FAM. These findings imply that heavy rainstorms may enhance the bonding of the major metals with humic substances mainly in the deciduous catchment; and also exhibit that, in the headwater catchments, both water flow pathways resulted from the different vegetation types play a very important role to promote the bonding of major metals with humic substances in stream water.

  14. Comparison of different DTM resolutions for surface change calculations in a high mountain environment

    Science.gov (United States)

    Rieg, L.; Sailer, R.; Sproß, M.; Rutzinger, M.; Wichmann, V.

    2012-04-01

    Working with high-resolution digital terrain models (DTMs) has become common practice for many geomorphologic and geomorphometric applications. Nowadays, with the up-come of Airborne Laser Scanning (ALS) and high resolution aerial photography, high resolution (1 m cell size or smaller) DTMs are available even for relatively large areas. With those high-resolution DTMs, the terrain is represented in a high level of detail, which means that small objects can be recognized. But while an adequate description of the terrain is positive at first glance, a high-resolution DTM may result in a representation of the terrain surface which offers more detail than relevant for a specific research application. Therefore, the objective of this work is to identify an appropriate cell size, which allows to retrieve enough information while using a minimum of data, i.e. a cell size as large as possible. The optimal cell size mainly depends on source point density, terrain complexity, and the scale of the intended application. An extensive set of ALS data (19 flight campaigns) covering the Hintereisferner Region in the Ötztal Alps (Tyrol, Austria) is used to calculate differences in surface elevation for several geomorphological processes of different frequencies and magnitudes such as fluvial erosion, melting of dead ice or a rock fall. These calculations were done using DTMs with different cell sizes (from 0.25 m to 2.00 m with a step size of 0.25 m and from 2.00 m to 10.00 m with a step size of 1.00 m) and a point to point calculation as reference data set. The point to point differences are assumed to represent the actual changes of the terrain caused by the geomorphologic processes in the most accurate way. However, access to point data is not obligatory and if available, point data computing is not trivial and time consuming. In this study, a standard point to raster conversion method is used for the calculation of the DTM with different cell-sizes, which show the smallest

  15. Excess erosion and deposition in the catchments of Kamenichka and Radanjska river, Republic of Macedonia

    Directory of Open Access Journals (Sweden)

    Milevski Ivica

    2009-01-01

    Full Text Available One of the greatest environmental problems in the Republic of Macedonia is accelerated soil erosion caused by high human impact during last centuries on to the susceptible landscape. Natural factors itself are very suitable for development of such erosion: from mostly erodible rocks and soils on the mountainous slopes around the depressions, to the generally continental, semi-arid climate and slight vegetation cover. Because of that, there are sites with severe erosion and deposition like those in the catchments of Kamenichka River and Radanjska River, two torrential tributaries of Bregalnica. In these catchments there are varieties of erosion-related landforms: rills, gullies, badlands, landslides, as well as valley-type alluvial fans and huge alluvial plains. Such devastating accelerated erosion and deposition largely transformed original landscape, and represent significant environmental, social, and economic problem in local areas. Because of that, some measures of protection and conservation were taken from 1950-ties in both catchments. But it is obvious that the final effect of these measures is far of enough, so new efforts must be implemented to revitalizing these abandoned lands.

  16. Modelling of snow processes in catchment hydrology by means of downscaled WRF meteorological data fields

    Science.gov (United States)

    Förster, K.; Meon, G.; Strasser, U.

    2014-04-01

    Detailed physically based snowmelt models require a complete set of meteorological forcing data at the model's scale. Besides precipitation and temperature, time series of humidity, wind speed, and radiation have to be provided. The availability of these time series is in many cases restricted to a few meteorological stations and consequently, snowmelt modelling is often highly uncertain. To overcome this dilemma, the suitability of downscaled atmospheric analysis data for physically based snowmelt simulations in hydrological modelling is studied. We used the Weather Research and Forecast model (WRF) to derive spatial and temporal fields of meteorological surface variables as boundary conditions for four different snowmelt models. The simulations were carried out at the point scale and at the catchment scale for the Sieber catchment (44.4 km2), Harz Mountains, Germany. For the latter, all snowmelt models were integrated into the hydrological modelling system PANTA RHEI. All models performed well at both scales. In conclusion, the presented approach is suitable to derive reliable estimates of snowpack and snowmelt processes as part of water balance and flood simulations for catchments exposed to snow.

  17. Catchment features controlling nitrogen dynamics in running waters above the tree line (central Italian Alps

    Directory of Open Access Journals (Sweden)

    R. Balestrini

    2013-03-01

    Full Text Available The study of nitrogen cycling in mountain areas has a long tradition, as it was applied to better understand and describe ecosystem functioning, as well as to quantify long-distance effects of human activities on remote environments. Nonetheless, very few studies, especially in Europe, have considered catchment features controlling nitrogen dynamics above the tree line with focus on running waters. In this study, relationships between some water chemistry descriptors – including nitrogen species and dissolved organic carbon (DOC – and catchment characteristics were evaluated for a range of sites located above the tree line (1950–2650 m a.s.l. at Val Masino, in the central Italian Alps. Land cover categories as well as elevation and slope were assessed at each site. Water samples were collected during the 2007 and 2008 snow free periods, with a nearly monthly frequency. In contrast to dissolved organic nitrogen, nitrate concentrations in running waters showed a spatial pattern strictly connected to the fractional extension of tundra and talus in each basin. Exponential models significantly described the relationships between maximum NO3 and the fraction of vegetated soil cover (negative relation and talus (positive relation, explaining almost 90% of nitrate variation in running waters. Similarly to nitrate but with an opposite behavior, DOC was positively correlated with vegetated soil cover and negatively correlated with talus. Therefore, land cover can be considered one of the most important factors affecting water quality in high-elevation catchments with contrasting effects on N and C pools.

  18. Between the high mountains and the deserts: reconstructing palaeoenvironments in the Arid Central Asian loess

    Science.gov (United States)

    Fitzsimmons, Kathryn; Sprafke, Tobias; Deom, Jean-Marc; Sala, Renato; Nigmatova, Saida

    2017-04-01

    Central Asia lies at the arid core of the largest and most populous continent on Earth - Eurasia - and at the intersection between the major climatic drivers of the North Atlantic westerlies, the polar front and the Asian monsoon. It furthermore represents a global "hotspot" for future desertification, facing a potent combination of sensitive climate dynamics and intensive land use. However, we know little about the role of Central Asia in global climate dynamics past and present. This is largely because we have yet to realise the full potential of the widespread loess archives which extend across the semi-arid piedmonts to the north of the Asian high mountains, at the southern margins of the Silk Road deserts. These records have been largely overlooked by scientific investigation, despite correlations between the well-studied loess archives of Europe and China. In spite of its key position in the northern hemisphere climate circulation systems, the climatic history - and trajectory - of arid Central Asia remains largely unknown. Here we reconstruct palaeoenvironmental change over the last 40 ky from three sites in the loess foothills of the northern Tien Shan. Our emerging sedimentological, palaeopedological, geochemical and geochronological datasets suggest that aeolian deposition in this semi-arid region responds in a more complex way to climate than the classical sequences of the Chinese Loess Plateau and Danube basin. In arid Central Asia, landscapes appear to have responded not only to the cooler and warmer conditions of the glacial and interglacial periods respectively, but also to the availability of moisture. Variations in precipitation patterns may have been out of phase with the ice ages, and the impact of precipitation regime change may have been intensified by an extreme continental climate. Emerging data from the Central Asian loess suggest that past climates may not only have been subject to spatial migration, expansion and contraction of the major

  19. Possible paths towards sustainable tourism development in a high-mountain resort

    Directory of Open Access Journals (Sweden)

    Laurent Arcuset

    2009-12-01

    Full Text Available This text starts from the teachings stemming from an evaluation of the tourist practices in the light of sustainable tourism principles, realized in 2004 within the framework of a national network piloted by the French Agency of Touristic Engineering (today ODIT France, for the ski resort of Valloire, first-generation resort in the Maurienne, which development and modernization in the 2000s kept pace with a vast real estate program. The article investigates the stakes and difficulties of the implementation of sustainable development in Valloire, asks the question of the "cultural revolution" which the actors should achieve to change the model of economic development, and suggest some tracks to reach there. The local approach of "sustainable tourism", indeed, seems for the moment rather to aim - as in many other high mountain ski resorts - towards a more environmental management of the basic urban functions than a real questioning of a tourist model based upon the triptych development of the ski slopes, securizing of the snow resource and touristic real estate programs.Ce texte part des enseignements issus d’une évaluation des pratiques touristiques à l’aune des principes du tourisme durable, réalisée en 2004 dans le cadre d’un réseau national piloté par l’Agence Française d’Ingénierie Touristique (aujourd’hui ODIT France, pour la station de Valloire, station de première génération de Maurienne dont le développement et la modernisation dans les années 2000 sont allés de pair avec un vaste programme immobilier. L’article explore les enjeux et les difficultés de la mise en œuvre du développement durable à Valloire, pose la question de la « révolution culturelle » que les acteurs devraient accomplir pour changer de modèle de développement économique, et suggère quelques pistes pour y parvenir. L’approche locale du « tourisme durable », en effet, semble pour l’heure plutôt tendre – comme dans bien

  20. Zooplankton abundance, species composition and ecology of tropical high-mountain crater lake Wonchi, Ethiopia

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    Fasil Degefu

    2014-11-01

    Full Text Available The highlands of Ethiopia represent some of the remnants of undisturbed aquatic ecosystems; they are however highly threatened by significant socio–economic developments and associated anthropogenic impacts. Lake Wonchi is one of the few remaining fairly pristine high–mountain crater lakes in the central highlands and has never been investigated in detail. We present a first study on zooplankton taxa composition, abundance and biomass conducted over more than one year including the underlying environmental drivers. The lake is basic (pH 7.9-8.9, dilute (specific conductivity 185-245 µS cm-1 and oligotrophic with mean trophic status index of 36. The zooplankton community composition showed low species richness comprising a total of fourteen taxa with six cladocerans, one copepod and seven rotifers. Simpson´s index of diversity with values between 0.6 and 0.8 pointed towards a homogenous taxa occurrence within the single sample units. The overall mean (±SD standing biomass of zooplankton was 62.02±25.76 mg dry mass m-3,which is low compared to other highland and rift valley lakes in Ethiopia. Cyclopoid copepods, in particular Thermocyclops ethiopiensis were the most abundant group and contributed 50% to the total zooplankton abundance followed by cladocerans (38% and rotifers (12%. Non-metric multi-dimensional scaling resulted in a 3-dimensional model, which revealed similar community composition on successive sampling dates except in December/January and May. Temperature, alkalinity, conductivity and nitrate-N had significant influence on this seasonal pattern. A weak, but significant positive correlation (r=0.482, N=20, P=0.037 between Chlorophyll a and zooplankton biomass mirrors a bottom-up effect of phytoplankton biomass on zooplankton dynamics. The zooplankton of Lake Wonchi displayed some degree of segregation along the epi– and metalimnion during this study, but diel vertical migration was not observed. The results show that fish

  1. Monitoring of High Mountain Glaciers in the Vicinity of Everest (Himalaya) using Remote Sensing Capability

    Science.gov (United States)

    Thakuri, S.; Salerno, F.; Bolch, T.; Smiraglia, C.; Tartari, G.

    2014-12-01

    studies in the high mountain Asia and conclude that the shrinkage of these glaciers are less than that of western and eastern Himalaya, and southern and eastern Tibetan Plateau. The location in higher elevations have likely reduced the impact of warming on these glaciers, but have not been excluded from a relentlessly continuous and slow recession process over the past 50 yrs.

  2. On the arsenic source mobilisation and its natural enrichment in the sediments of a high mountain cirque in the Pyrenees.

    Science.gov (United States)

    Zaharescu, Dragos George; Hooda, Peter S; Fernandez, Javier; Soler, Antonio Palanca; Burghelea, Carmen Ionela

    2009-11-01

    Recently arsenic contamination and its environmental and human health problems have been raising concerns worldwide. The occurrence of natural high levels of arsenic contamination has generally been reported for low altitude environments. Here we report a study conducted to assess the extent of arsenic mobilisation/transportation from previously identified arsenic source areas in a high altitude cirque of the Pyrenees as well as the potential contribution of As by snow. The concentration of arsenic in sediments of several tributaries was enriched up to about ten folds due to mobilisation of arsenic from the source areas within the catchment. The highest arsenic enrichments were found in an area dominated by quartzite and slate formation in the southern side of the basin, and it generally diminished towards the major lake downstream, possible due to mixing with sediments from non-source areas. At these sites arsenic exceeded the hazard quotient (HQ) limits for the protection of aquatic life. The potential hazard of the As-enriched sediments may be further enhanced outside the catchment as samples collected downstream the cirque have also shown arsenic concentration exceeding HQ unity. The arsenic concentrations in the water collected at a number of sites exceeded its guide value for the protection of aquatic life. The potential As contribution by snow in the area was low and was largely of lithospheric origin. The PCA analysis showed strong association of arsenic in sediments with the sediment mineralogical composition (Fe2O3, TiO2 and Mn). Arsenic in water was positively correlated with its concentration in the sediments and could potentially increase if the environmental/climate conditions change.

  3. Localized bedrock aquifer distribution explains discharge from a headwater catchment

    Science.gov (United States)

    Kosugi, Ken'ichirou; Fujimoto, Masamitsu; Katsura, Shin'ya; Kato, Hiroyuki; Sando, Yoshiki; Mizuyama, Takahisa

    2011-07-01

    Understanding a discharge hydrograph is one of the leading interests in catchment hydrology. Recent research has provided credible information on the importance of bedrock groundwater on discharge hydrographs from headwater catchments. However, intensive monitoring of bedrock groundwater is rare in mountains with steep topography. Hence, how bedrock groundwater controls discharge from a steep headwater catchment is in dispute. In this study, we conducted long-term hydrological observations using densely located bedrock wells in a headwater catchment underlain by granitic bedrock. The catchment has steep topography affected by diastrophic activities. Results showed a fairly regionalized distribution of bedrock aquifers within a scale of tens of meters, consisting of upper, middle, and lower aquifers, instead of a gradual and continuous decline in water level from ridge to valley bottom. This was presumably attributable to the unique bedrock structure; fault lines developed in the watershed worked to form divides between the bedrock aquifers. Spatial expanse of each aquifer and the interaction among aquifers were key factors to explain gentle and considerable variations in the base flow discharge and triple-peak discharge responses of the observed hydrograph. A simple model was developed to simulate the discharge hydrograph, which computed each of the contributions from the soil mantle groundwater, from the lower aquifer, and from the middle aquifer to the discharge. The modeling results generally succeeded in reproducing the observed hydrograph. Thus, this study demonstrated that understanding regionalized bedrock aquifer distribution is pivotal for explaining discharge hydrograph from headwater catchments that have been affected by diastrophic activities.

  4. From Mountains to Plains: The Hydrogeochemistry of the Boulder Creek Watershed, Colorado during High- and Low-Flow Conditions 2000

    Science.gov (United States)

    Verplanck, P. L.; Murphy, S. F.; McCleskey, R. B.; Barber, L. B.; Roth, D. A.

    2002-05-01

    A hydrogeochemical study of the Boulder Creek watershed was undertaken to evaluate natural and anthropogenic sources of solutes and the geochemical processes that affect stream chemistry. The Boulder Creek watershed, 1160 km{2}, is in the Front Range of the Rocky Mountains in Colorado and can be delineated into five physiographic/land use regions: the headwater region (elev. 4100 to 2600 m, tundra to pine/fir forest, Precambrian and Tertiary gneisses and plutons, sparse habitation), the mountain corridor (elev. 2600 to 1750 m, ponderosa pine, Precambrian and Tertiary gneisses and plutons, small mountain communities), the urban region (elev. 1750 to 1560 m, grassland, Mesozoic sedimentary units, City of Boulder), the wastewater-dominated reach (elev. 1560 to 1540 m, grassland, Mesozoic sedimentary units, sewage treatment plant effluent), and the agriculture region (elev. 1540 to 1480 m, grassland, Mesozoic sedimentary units, mixed urban and agricultural). Potential anthropogenic sources of solutes include: mining (hardrock and aggregate), septic systems, highway runoff, urban wastewater, and agricultural practices. A 70 km reach of Boulder Creek (16 sites) and its major inflows (13 sites) were sampled during high- and low-flow conditions in 2000. At all sites, discharge was measured or estimated, and water samples were analyzed for major and trace elements and organic carbon. At selected sites, analyses also included a suite of pesticides, pharmaceuticals, and wastewater-derived organic compounds and the strontium isotopic composition. Stream water in the headwater region is a dilute Ca-Mg-HCO3-SO4- water, and in the mountain corridor a slight increase in solutes was observed. Within the urban reach solute concentrations increased, with the most dramatic increase below the sewage treatment plant. Many constituents continue to increase in concentration through the urban/agriculture region. Similar trends were observed during high- and low-flow conditions with

  5. Importance of Field Work in Natural Disaster Risk Assessments in High Mountains

    Science.gov (United States)

    Mckinney, D. C.; Somos-valenzuela, M. A.; Byers, A. C.

    2012-12-01

    Increase in glacier melting leads to the formation of new glacier lakes at the snout of glaciers in high elevations. It is common to find moraine-dammed lakes and glacier lake outburst floods (GLOFs) in different glacierized regions. GLOFs can affect fragile mountain ecosystems as well as economic activities due to the large magnitude of the flow. The complexity of this problem is increased by the remoteness of the areas and the lack of data, and the majority of risk assessments are based on remote observations such as satellite imaginary and aerial photography. The Dudh Koshi basin contains twelve of the twenty potentially dangerous glacial lakes of Nepal. In May 2012 ground penetrating radar surveys were completed at three glacier lakes in Nepal to measure the moraine thickness and detect the presence of ice in the moraines. The lakes were: Dudh Pokhari, considered to be high risk due to its volume; Tama Pokhari, considered to be low risk after a 1998 GLOF; and Imja Lake, considered to be high risk due to its large volume. Due to expansion in the direction of the Imja glacier instead of the moraine during the last decade and the extensive terminal moraine complex there has been a belief that Imja lake will not have a GLOF in the near future. This work highlights the idea that to have an accurate risk assessment, fieldwork needs to be one of the main sources of information, which could be mixed with remote sensing and numerical modeling. For these lakes we found: Dudh Pokhari does not show evident risk since it does not have evident triggers such as overhanging ice. Tama Pokhari was drained considerably in the 1998 GLOF; however, some risk remains since there are many hanging glaciers and the volume of the lake is not well known. Community members mentioned that twice some ice has fallen into the lake producing waves, which overtopped the moraine and generated floods downstream. At Imja Lake, extensive GPR surveys were run at the terminal moraine and indicated the

  6. Simulating wind-affected snow accumulations at catchment to basin scales

    Science.gov (United States)

    Winstral, Adam; Marks, Danny; Gurney, Robert

    2013-05-01

    In non-forested mountain regions, wind plays a dominant role in determining snow accumulation and melt patterns. A new, computationally efficient algorithm for distributing the complex and heterogeneous effects of wind on snow distributions was developed. The distribution algorithm uses terrain structure, vegetation, and wind data to adjust commonly available precipitation data to simulate wind-affected accumulations. This research describes model development and application in three research catchments in the Reynolds Creek Experimental Watershed in southwest Idaho, USA. All three catchments feature highly variable snow distributions driven by wind. The algorithm was used to derive model forcings for Isnobal, a mass and energy balance distributed snow model. Development and initial testing took place in the Reynolds Mountain East catchment (0.36 km2) where R2 values for the wind-affected snow distributions ranged from 0.50 to 0.67 for four observation periods spanning two years. At the Upper Sheep Creek catchment (0.26 km2) R2 values for the wind-affected model were 0.66 and 0.70. These R2 values matched or exceeded previously published cross-validation results from regression-based statistical analyses of snow distributions in similar environments. In both catchments the wind-affected model accurately located large drift zones, snow-scoured slopes, and produced melt patterns consistent with observed streamflow. Models that did not account for wind effects produced relatively homogenous SWE distributions, R2 values approaching 0.0, and melt patterns inconsistent with observed streamflow. The Dobson Creek (14.0 km2) application incorporated elevation effects into the distribution routine and was conducted over a two-dimensional grid of 6.67 × 105 pixels. Comparisons with satellite-derived snow-covered-area again demonstrated that the model did an excellent job locating regions with wind-affected snow accumulations. This final application demonstrated that the

  7. Microbial water quality in the upper Olifants River catchment: implications for health

    CSIR Research Space (South Africa)

    Le Rouw, Wouter J

    2012-10-01

    Full Text Available A quantitative microbial risk assessment of water in the upper Olifants River catchment showed that sections of the catchment are highly contaminated with faecal indicator bacteria and pathogenic micro-organisms and that the polluted waters pose...

  8. Rates and causes of accidents for general aviation aircraft operating in a mountainous and high elevation terrain environment.

    Science.gov (United States)

    Aguiar, Marisa; Stolzer, Alan; Boyd, Douglas D

    2017-10-01

    Flying over mountainous and/or high elevation terrain is challenging due to rapidly changeable visibility, gusty/rotor winds and downdrafts and the necessity of terrain avoidance. Herein, general aviation accident rates and mishap cause/factors were determined (2001-2014) for a geographical region characterized by such terrain. Accidents in single piston engine-powered aircraft for states west of the US continental divide characterized by mountainous terrain and/or high elevation (MEHET) were identified from the NTSB database. MEHET-related-mishaps were defined as satisfying any one, or more, criteria (controlled flight into terrain/obstacles (CFIT), downdrafts, mountain obscuration, wind-shear, gusting winds, whiteout, instrument meteorological conditions; density altitude, dust-devil) cited as factors/causal in the NTSB report. Statistics employed Poisson distribution and contingency tables. Although the MEHET-related accident rate declined (p<0.001) 57% across the study period, the high proportion of fatal accidents showed little (40-43%) diminution (χ 2 =0.935). CFIT and wind gusts/shear were the most frequent accident cause/factor categories. For CFIT accidents, half occurred in degraded visibility with only 9% operating under instrument flight rules (IFR) and the majority (85%) involving non-turbo-charged engine-powered aircraft. For wind-gust/shear-related accidents, 44% occurred with a cross-wind exceeding the maximum demonstrated aircraft component. Accidents which should have been survivable but which nevertheless resulted in a fatal outcome were characterized by poor accessibility (60%) and shoulder harness under-utilization (41%). Despite a declining MEHET-related accident rate, these mishaps still carry an elevated risk of a fatal outcome. Airmen should be encouraged to operate in this environment utilizing turbo-charged-powered airplanes and flying under IFR to assure terrain clearance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Population demography of alpine butterflies: Boloria pales and Boloria napaea (Lepidoptera: Nymphalidae) and their specific adaptations to high mountain environments

    Science.gov (United States)

    Ehl, Stefan; Ebertshäuser, Marlene; Gros, Patrick; Schmitt, Thomas

    2017-11-01

    High mountain ecosystems are extreme habitats, and adaptation strategies to this ecosystem are still poorly understood in most groups. To unravel such strategies, we performed a MRR study in the Hohe Tauern National Park (Salzburg, Austria) with two nymphalid butterfly species, Boloria pales and B. napaea. We analysed their population structure over one flight period by studying the development of population size and wing wear. B. pales had more individuals and a higher survival probability than B. napaea; the sensitivity to extreme weather conditions or other external influences was higher in B. napaea. We only observed proterandry in B. pales. Imagines of both species survived under snow for at least some days. Additionally, we observed a kind of risk-spreading, in that individuals of both species, and especially B. pales, have regularly emerged throughout the flight period. This emergence pattern divided the population's age structure into three phases: an initial phase with decreasing wing quality (emergence > mortality), followed by an equilibrium phase with mostly constant average wing condition (emergence = mortality) and a final ageing phase with strongly deteriorating wing condition (mortality » emergence). Consequently, neither species would likely become extinct because of particularly unsuitable weather conditions during a single flight period. The observed differences between the two species suggest a better regional adaptation of B. pales, which is restricted to high mountain systems of Europe. In contrast, the arctic-alpine B. napaea might be best adapted to conditions in the Arctic and not the more southern high mountain systems. However, this needs to be examined during future research in the Arctic.

  10. Genotype and year variability of the chemical composition of walnut oil of Moroccan seedlings from the high Atlas Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Kodad, O.; EstopaNan, G.; Juan, T.; Socias i Company, R.; Sindic, M.

    2016-07-01

    Protein and oil content, fatty acid composition and tocopherol concentration were determined for two years in the kernel of ten candidate walnut selections from the high Atlas Mountains in Morocco. Considerable variation between genotypes was found for all parameters. The ranges of protein content (11.58–14.5% of kernel dry weight, DW), oil content (54.4–67.48% of kernel DW), oleic (12.47–22.01% of total oil), linoleic (55.03–60.01%), linolenic (9.3–15.87%), palmitic (6.84–9.12%), and stearic (1.7–2.92%) acid percentages, ?-tocopherol (188.1–230.7 mg·kg-1 of oil), d-tocopherol (23.3–43.4 mg·kg-1), and a-tocopherol (8.9–16.57 mg·kg-1) contents agreed with previous results obtained from other commercial walnut cultivars. The effect of year was significant for all the chemical components, except for oil content and palmitic acid percentage. Some genotypes showed high oil contents and consistently high values of ?-tocopherol in both years of study. The introduction of these genotypes as new cultivars by vegetative propagation may result in a an increase in quality of the walnuts from the high Atlas Mountains of Morocco, and as a seed source for forest walnut propagation in the same region. (Author)

  11. Spatial Patterns of Atmospherically Deposited Organic Contaminants at High Elevation in the Southern Sierra Nevada Mountains, California

    Science.gov (United States)

    Atmospherically deposited contaminants in the Sierra Nevada mountains of California have been implicated as a factor adversely affecting biological resources such as amphibians and fish, yet the distributions of contaminants within the mountains are poorly known, particularly at...

  12. Trends in dynamics of forest upper boundary in high mountains of northern Baikal area

    Directory of Open Access Journals (Sweden)

    V. I. Voronin

    2016-08-01

    Full Text Available Studies of spatial-temporal variability of the upper boundary of the forest on the north-western coast of Lake Baikal (Baikal and Upper Angara Ridges are performed on the base of the analysis of forests renewal processes and of the dynamics of larch radial increment in the ecotone of the forest upper boundary and out of it. The presence of a large amount of well-developed uplands and circuses with considerable heights drops in the structure of mountain system favours formation of interrupted boundary between forest and subgoltsy belt. The timber stand of the upper forest boundary in the studied area is represented by Daurian larch. Three tree-ring chronologies of larch are obtained. The longest chronology is obtained for mountain taiga belt of Baikal Ridge and is as long as 460 years. Since 1980ies, a sustainable trend of increase of radial trees growth is observed. It is observed the most distinctly in trees of the upper forest boundary on the Baikal Ridge. There is advancing of trees species into subgoltsy belt and into mountain tundra, which depends, respectively, on slopes heights, exposition and tilting, on sites of growth of concrete cenoses. Modern peculiarity of the vegetation of the studied area is presence of abundant viable larch undergrowth (from 2–3 to 25 y.o. and fir in the ecotone of upper forest boundary and in subgoltsy belt, as well as appearing of single specimens of spruce. Main undergrowth mass (2/3 is presented by trees aged in average 15–25 y.o., i.e., they appeared in late 1980ies. Due to increase of snow cover thickness in winter, the trees young growth obtained great protection from freezing resulting in the increase of ability of young growth to live up to elder age.

  13. Mountain Rivers and Climate Change: Analysis of hazardous events in torrents of small alpine watersheds

    Science.gov (United States)

    Lutzmann, Silke; Sass, Oliver

    2016-04-01

    Torrential processes like flooding, heavy bedload transport or debris flows in steep mountain channels emerge during intense, highly localized rainfall events. They pose a serious risk on the densely populated Alpine region. Hydrogeomorphic hazards are profoundly nonlinear, threshold mediated phenomena frequently causing costly damage to infrastructure and people. Thus, in the context of climate change, there is an ever rising interest in whether sediment cascades of small alpine catchments react to changing precipitation patterns and how the climate signal is propagated through the fluvial system. We intend to answer the following research questions: (i) What are critical meteorological characteristics triggering torrential events in the Eastern Alps of Austria? (ii) The effect of external triggers is strongly mediated by the internal disposition of catchments to respond. Which factors control the internal susceptibility? (iii) Do torrential processes show an increase in magnitude and frequency or a shift in seasonality in the recent past? (iv) Which future changes can be expected under different climate scenarios? Quantifications of bedload transport in small alpine catchments are rare and often associated with high uncertainties. Detailed knowledge though exists for the Schöttlbach catchment, a 71 km2 study area in Styria in the Eastern Alps. The torrent is monitored since a heavy precipitation event resulted in a disastrous flood in July 2011. Sediment mobilisation from slopes as well as within-channel storage and fluxes are regularly measured by photogrammetric methods and sediment impact sensors (SIS). The associated hydro-meteorological conditions are known from a dense station network. Changing states of connectivity can thus be related to precipitation and internal dynamics (sediment availability, cut-and-fill cycles). The site-specific insights are then conceptualized for application to a broader scale. Therefore, a Styria wide database of torrential

  14. Process chains in high mountain areas and multi-hazards of different scales - the Barsem disaster, Tajikistan

    Science.gov (United States)

    Zimmermann, Markus; Fuchs, Sven; Keiler, Margreth

    2016-04-01

    Changes in high-mountain environments are responsible for new and challenging multi-hazard conditions and materialize in particular through cases such as the Barsem disaster (Pamir, Tajikistan) in July 2015. At least 14 major debris flows occurred in the Barsem Valley within four days during a period of exceptional meteorological conditions. The flows transported large volumes of debris on the fan where the village Barsem with about 1,500 inhabitants is located. As a result, 80 homes were completely destroyed, and one person went lost. Moreover, the debris dammed the Gunt River, forming a lake of two kilometers length and endangering the local power supply. The lake interrupted the Pamir Highway and the potential lake outburst threatened the downstream communities along the valley as well as Khorog, the capital of the Gorno Badakhshan Autonomous Oblast. The damage was caused directly by the debris flows deposits and by subsequent flooding as a consequence of dammed Gunt River. This contribution will provide a first analysis of the conditions in the debris flow starting zone and the triggering of the event, the sediment connectivity during the event and further consequences downstream related to the accumulated debris dam at the Gunt River. Furthermore, the analysis will be supported by a comparison between different events in the Pamir region and the European Alps focusing on geomorphological features in the starting zone, processes sequences, process-process interactions but also on emerging multi-hazard situation in this context. Increasing challenges due to changes in the high-mountain environment will be discusses for the Pamir region as well as the comparability between different mountain regions.

  15. Some Materials Degradation Issues in the U.S. High-Level Nuclear Waste Repository Study (The Yucca Mountain Project)

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; P. Pasupathi; N. Brown; K. Mon

    2005-09-19

    The safe disposal of radioactive waste requires that the waste be isolated from the environment until radioactive decay has reduced its toxicity to innocuous levels for plants, animals, and humans. All of the countries currently studying the options for disposing of high-level nuclear waste (HLW) have selected deep geologic formations to be the primary barrier for accomplishing this isolation. In U.S.A., the Nuclear Waste Policy Act of 1982 (as amended in 1987) designated Yucca Mountain in Nevada as the potential site to be characterized for high-level nuclear waste (HLW) disposal. Long-term containment of waste and subsequent slow release of radionuclides into the geosphere will rely on a system of natural and engineered barriers including a robust waste containment design. The waste package design consists of a highly corrosion resistant Ni-based Alloy 22 cylindrical barrier surrounding a Type 316 stainless steel inner structural vessel. The waste package is covered by a mailbox-shaped drip shield composed primarily of Ti Grade 7 with Ti Grade 24 structural support members. The U.S. Yucca Mountain Project has been studying and modeling the degradation issues of the relevant materials for some 20 years. This paper reviews the state-of-the-art understanding of the degradation processes based on the past 20 years studies on Yucca Mountain Project (YMP) materials degradation issues with focus on interaction between the in-drift environmental conditions and long-term materials degradation of waste packages and drip shields within the repository system during the 10,000 years regulatory period. This paper provides an overview of the current understanding of the likely degradation behavior of the waste package and drip shield in the repository after the permanent closure of the facility. The degradation scenario discussed in this paper include aging and phase instability, dry oxidation, general and localized corrosion, stress corrosion cracking and hydrogen induced

  16. Seasonal contribution of terrestrial organic matter and biological oxygen demand to the Baltic Sea from three contrasting river catchments

    DEFF Research Database (Denmark)

    Reader, H. E.; Stedmon, C. A.; Kritzberg, E. S.

    2014-01-01

    To examine the potential influence of terrestrially derived DOM on the Baltic Sea, a year-long study of dissolved organic matter (DOM) was performed in three river catchments in Sweden. One catchment drains into the Bothnian Sea, while two southern catchments drain into the Baltic proper. Dissolved...... times higher than in the southern two catchments. Total annual BOD loading to the Baltic Sea was twice as high in the northern catchment than in the two southern catchments. Lower winter temperatures and preservation of organic matter in the northern catchment combined with an intense spring flood help...

  17. Trends in annual minimum exposed snow and ice cover in High Mountain Asia from MODIS

    Science.gov (United States)

    Rittger, Karl; Brodzik, Mary J.; Painter, Thomas H.; Racoviteanu, Adina; Armstrong, Richard; Dozier, Jeff

    2016-04-01

    Though a relatively short record on climatological scales, data from the Moderate Resolution Imaging Spectroradiometer (MODIS) from 2000-2014 can be used to evaluate changes in the cryosphere and provide a robust baseline for future observations from space. We use the MODIS Snow Covered Area and Grain size (MODSCAG) algorithm, based on spectral mixture analysis, to estimate daily fractional snow and ice cover and the MODICE Persistent Ice (MODICE) algorithm to estimate the annual minimum snow and ice fraction (fSCA) for each year from 2000 to 2014 in High Mountain Asia. We have found that MODSCAG performs better than other algorithms, such as the Normalized Difference Index (NDSI), at detecting snow. We use MODICE because it minimizes false positives (compared to maximum extents), for example, when bright soils or clouds are incorrectly classified as snow, a common problem with optical satellite snow mapping. We analyze changes in area using the annual MODICE maps of minimum snow and ice cover for over 15,000 individual glaciers as defined by the Randolph Glacier Inventory (RGI) Version 5, focusing on the Amu Darya, Syr Darya, Upper Indus, Ganges, and Brahmaputra River basins. For each glacier with an area of at least 1 km2 as defined by RGI, we sum the total minimum snow and ice covered area for each year from 2000 to 2014 and estimate the trends in area loss or gain. We find the largest loss in annual minimum snow and ice extent for 2000-2014 in the Brahmaputra and Ganges with 57% and 40%, respectively, of analyzed glaciers with significant losses (p-value<0.05). In the Upper Indus River basin, we see both gains and losses in minimum snow and ice extent, but more glaciers with losses than gains. Our analysis shows that a smaller proportion of glaciers in the Amu Darya and Syr Darya are experiencing significant changes in minimum snow and ice extent (3.5% and 12.2%), possibly because more of the glaciers in this region are smaller than 1 km2 than in the Indus

  18. Contribution of atmospheric dry deposition to stormwater loads for PAHs and trace metals in a small and highly trafficked urban road catchment.

    Science.gov (United States)

    Al Ali, Saja; Debade, Xavier; Chebbo, Ghassan; Béchet, Béatrice; Bonhomme, Céline

    2017-12-01

    A deep understanding of pollutant buildup and wash-off is essential for accurate urban stormwater quality modeling and for the development of stormwater management practices, knowing the potential adverse impacts of runoff pollution on receiving waters. In the context of quantifying the contribution of airborne pollutants to the contamination of stormwater runoff and assessing the need of developing an integrated AIR-WATER modeling chain, loads of polycyclic aromatic hydrocarbons (PAHs) and metal trace elements (MTEs) are calculated in atmospheric dry deposits, stormwater runoff, and surface dust stock within a small yet highly trafficked urban road catchment (~ 30,000 vehicles per day) near Paris. Despite the important traffic load and according to the current definition of "atmospheric" source, atmospheric deposition did not account for more than 10% of the PAHs and trace metal loads in stormwater samples for the majority of the events, based on the ratio of deposition to stormwater. This result shows that atmospheric deposition is not a major source of pollutants in stormwater, and thus, linking the air and water compartment in a modeling chain to have more accurate estimates of pollutant loads in stormwater runoff might not be relevant. Comparison of road dust with water samples demonstrates that only the fine fraction of the available stock is eroded during a rainfall event. Even if the atmosphere mostly generates fine particles, the existence of other sources of fine particles to stormwater runoff is highlighted.

  19. Regional nitrogen dynamics in the TERENO Bode River catchment, Germany, as constrained by stable isotope patterns.

    Science.gov (United States)

    Mueller, Christin; Krieg, Ronald; Merz, Ralf; Knöller, Kay

    2016-01-01

    Interactions between hydrological characteristics and microbial activities affect the isotopic composition of dissolved nitrate in surface water. Nitrogen and oxygen isotopic signatures of riverine nitrate in 133 sampling locations distributed over the Bode River catchment in the Harz Mountains, Germany, were used to identify nitrate sources and transformation processes. An annual monitoring programme consisting of seasonal sampling campaigns in spring, summer and autumn was conducted. δ(15)N and δ(18)O of nitrate and corresponding concentrations were measured as well as δ(2)H and δ(18)O of water to determine the deuterium excess. In addition, precipitation on 25 sampling stations was sampled and considered as a potential input factor. The Bode River catchment is strongly influenced by agricultural land use which is about 70 % of the overall size of the catchment. Different nitrogen sources such as ammonia (NH4) fertilizer, soil nitrogen, organic fertilizer or nitrate in precipitation show partly clear nitrate isotopic differences. Processes such as microbial denitrification result in fractionation and lead to an increase in δ(15)N of nitrate. We observed an evident regional and partly temporal variation of nitrate isotope signatures which are clearly different between main landscape types. Spring water sections within the high mountains contain nitrate in low concentrations with low δ(15)NNO3 values of -3 ‰ and high δ(18)ONO3 values up to 13 ‰. High mountain stream water sub-catchments dominated by nearly undisturbed forest and grassland contribute nitrate with δ(15)NNO3 and δ(18)ONO3 values of -1 and -3.5 ‰, respectively. In the further flow path, which is affected by an increasing agricultural land use and urban sewage, we recognized an increase in δ(15)NNO3 and δ(18)ONO3 up to 22 and 18 ‰, respectively, with high variations during the year. A correlation seems to exist between the percentage of agricultural land use area and the

  20. Project solution for water use from the catchment area on Kozuf, Republic of Macedonia

    OpenAIRE

    Spasovski, Orce; Spasovski, Daniel

    2013-01-01

    In this paper will be show possible use of mineral waters from the catchment area on the mountain Kozuf. Project solution for using the mineral waters of this area, despite the general part gives way to the exploitation of mineral waters, technical - economic assessment of exploitation and environmental protection. Exploitation of mineral waters will be carried out from the catchment facilities - capturing the springs Bukata, Stenata and Studena Voda - Rimjanka and the captured...

  1. Changing trends of rainfall and sediment fluxes in the Kinta River catchment, Malaysia

    Directory of Open Access Journals (Sweden)

    W. R. Ismail

    2015-03-01

    Full Text Available The Kinta River, draining an area of 2566 km2, originates in the Korbu Mountain in Perak, Malaysia, and flows through heterogeneous, mixed land uses ranging from extensive forests to mining, rubber and oil palm plantations, and urban development. A land use change analysis of the Kinta River catchment was carried out together with assessment of the long-term trend in rainfall and sediment fluxes. The Mann-Kendall test was used to examine and assess the long-term trends in rainfall and its relationship with the sediment discharge trend. The land use analysis shows that forests, water bodies and mining land declined whilst built and agricultural land use increased significantly. This has influenced the sediment flux of the catchment. However, most of the rainfall stations and river gauging stations are experiencing an increasing trends, except at Kinta river at Tg. Rambutan. Sediment flux shows a net erosion for the period from 1961 to 1969. The total annual sediment discharge in the Kinta River catchment was low with an average rate of 1,757 t/km2/year. From 1970 to 1985, the annual sediment yield rose to an average rate of 4062 t/km2/year. Afterwards, from 1986 to 1993, the total annual sediment discharge decreased to an average rate of 1,306 t/km2/year and increased back during the period 1994 to 2000 to 2109 t/km2/year. From 2001 to 2006 the average sediment flux rate declined to 865 t/km2/year. The decline was almost 80% from the 1970s. High sediment flux in the early 1970s is partly associated with reduced tin mining activities in the area. This decreasing trend in sediment delivery leaving the Kinta River catchment is expected to continue dropping in the future.

  2. Sediment transport dynamics in steep, tropical volcanic catchments

    Science.gov (United States)

    Birkel, Christian; Solano Rivera, Vanessa; Granados Bolaños, Sebastian; Brenes Cambronero, Liz; Sánchez Murillo, Ricardo; Geris, Josie

    2017-04-01

    How volcanic landforms in tropical mountainous regions are eroded, and how eroded materials move through these mostly steep landscapes from the headwaters to affect sediment fluxes are critical to water resources management in their downstream rivers. Volcanic landscapes are of particular importance because of the short timescales (natural runoff, erosion and sediment fluxes. Sediment transport is also directly linked to carbon and solute export. However, knowledge on the sediment sources and transport dynamics in the humid tropics remains limited and their fluxes largely unquantified. In order to increase our understanding of the dominant erosion and sediment transport dynamics in humid tropical volcanic landscapes, we conducted an extensive monitoring effort in a pristine and protected (biological reserve Alberto Manuel Brenes, ReBAMB) tropical forest catchment (3.2 km2), located in the Central Volcanic Cordillera of Costa Rica (Figure 1A). Typical for tropical volcanic and montane regions, deeply incised V-form headwaters (Figure 1B) deliver the majority of water (>70%) and sediments to downstream rivers. At the catchment outlet (Figure 1C) of the San Lorencito stream, we established high temporal resolution (5min) water quantity and sediment monitoring (turbidity). We also surveyed the river network on various occasions to characterize fluvial geomorphology including material properties. We could show that the rainfall-runoff-sediment relationships and their characteristic hysteresis patterns are directly linked to variations in the climatic input (storm intensity and duration) and the size, form and mineralogy of the transported material. Such a relationship allowed us to gain the following insights: (i) periodic landslides contribute significant volumes of material (> 100m3 per year) to the stream network, (ii) rainfall events that exceed a threshold of around 30mm/h rain intensity activate superficial flow pathways with associated mobilization of sediments

  3. Estimating density of a rare and cryptic high-mountain Galliform species, the Buff-throated Partridge Tetraophasis szechenyii

    Directory of Open Access Journals (Sweden)

    Yu Xu

    2016-06-01

    Full Text Available Estimates of abundance or density are essential for wildlife management and conservation. There are few effective density estimates for the Buff-throated Partridge Tetraophasis szechenyii, a rare and elusive high-mountain Galliform species endemic to western China. In this study, we used the temporary emigration N-mixture model to estimate density of this species, with data acquired from playback point count surveys around a sacred area based on indigenous Tibetan culture of protection of wildlife, in Yajiang County, Sichuan, China, during April-June 2009. Within 84 125-m radius points, we recorded 53 partridge groups during three repeats. The best model indicated that detection probability was described by covariates of vegetation cover type, week of visit, time of day, and weather with weak effects, and a partridge group was present during a sampling period with a constant probability. The abundance component was accounted for by vegetation association. Abundance was substantially higher in rhododendron shrubs, fir-larch forests, mixed spruce-larch-birch forests, and especially oak thickets than in pine forests. The model predicted a density of 5.14 groups/km², which is similar to an estimate of 4.7 - 5.3 groups/km² quantified via an intensive spot-mapping effort. The post-hoc estimate of individual density was 14.44 individuals/km², based on the estimated mean group size of 2.81. We suggest that the method we employed is applicable to estimate densities of Buff-throated Partridges in large areas. Given importance of a mosaic habitat for this species, local logging should be regulated. Despite no effect of the conservation area (sacred on the abundance of Buff-throated Partridges, we suggest regulations linking the sacred mountain conservation area with the official conservation system because of strong local participation facilitated by sacred mountains in land conservation.

  4. Incorporating wind availability into land use regression modelling of air quality in mountainous high-density urban environment.

    Science.gov (United States)

    Shi, Yuan; Lau, Kevin Ka-Lun; Ng, Edward

    2017-08-01

    Urban air quality serves as an important function of the quality of urban life. Land use regression (LUR) modelling of air quality is essential for conducting health impacts assessment but more challenging in mountainous high-density urban scenario due to the complexities of the urban environment. In this study, a total of 21 LUR models are developed for seven kinds of air pollutants (gaseous air pollutants CO, NO 2 , NO x , O 3 , SO 2 and particulate air pollutants PM 2.5 , PM 10 ) with reference to three different time periods (summertime, wintertime and annual average of 5-year long-term hourly monitoring data from local air quality monitoring network) in Hong Kong. Under the mountainous high-density urban scenario, we improved the traditional LUR modelling method by incorporating wind availability information into LUR modelling based on surface geomorphometrical analysis. As a result, 269 independent variables were examined to develop the LUR models by using the "ADDRESS" independent variable selection method and stepwise multiple linear regression (MLR). Cross validation has been performed for each resultant model. The results show that wind-related variables are included in most of the resultant models as statistically significant independent variables. Compared with the traditional method, a maximum increase of 20% was achieved in the prediction performance of annual averaged NO 2 concentration level by incorporating wind-related variables into LUR model development. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Phylogeny and diversification of mountain vipers (Montivipera, Nilson et al., 2001) triggered by multiple Plio-Pleistocene refugia and high-mountain topography in the Near and Middle East.

    Science.gov (United States)

    Stümpel, Nikolaus; Rajabizadeh, Mehdi; Avcı, Aziz; Wüster, Wolfgang; Joger, Ulrich

    2016-08-01

    The Near and Middle East is a hotspot of biodiversity, but the region remains underexplored at the level of genetic biodiversity. Here, we present an extensive molecular phylogeny of the viperid snake genus Montivipera, including all known taxa. Based on nuclear and mitochondrial data, we present novel insights into the phylogeny of the genus and review the status of its constituent species. Maximum likelihood methods revealed a montane origin of Montivipera at 12.3Mya. We then analyzed factors of mountain viper diversity. Our data support substantial changes in effective population size through Plio-Pleistocene periods. We conclude that climatic oscillations were drivers of allopatric speciation, and that mountain systems of the Near and Middle East have strongly influenced the evolution and survival of taxa, because climatic and topographical heterogeneities induced by mountains have played a crucial role as filters for dispersal and as multiple refugia. The wide diversity of montane microhabitats enabled mountain vipers to retain their ecological niche during climatic pessima. In consequence the varied geological and topographical conditions between refugia favoured genetic isolation and created patterns of species richness resulting in the formation of neoendemic taxa. Our data support high concordance between geographic distributions of Montivipera haplotypes with putative plant refugia. Copyright © 2016. Published by Elsevier Inc.

  6. Phosphorus sources and losses in two arable catchments and implications for catchment management

    Science.gov (United States)

    Murphy, P. N. C.; Melland, A. R.; Mellander, P.-E.; Shortle, G.; Wall, D.; Jordan, P.

    2012-04-01

    Multi-scale catchment experiments allow assessment of the impact of policy measures on nutrient losses from agriculture and water quality and testing of conceptual models of nutrient loss. The potential for catchment-specific responses to be extrapolated to similar catchments country-wide can then help guide future policy measures to achieve water quality targets, such as those in the EU Water Framework Directive (WFD). This paper presents results from the Agricultural Catchments Programme; an integrated advisory/research programme working with stakeholders to assess the efficacy of Ireland's National Action Programme (NAP) of measures in meeting the targets of the Nitrates Directive and WFD. Results are presented for P sources and losses over two water years in two catchments (9.5 and 11.2 km2) with intensive arable agriculture but contrasting soil drainage and geology and resultant hydrologic and nutrient transfer pathways. Phosphorus source pressures were characterised in terms of field-scale soil P status and P balances. Phosphorus loss was characterised in terms of P concentration and loads monitored with high-resolution bank-side analysers. Despite having similar P soil status (18-19 % in excess of agronomic optimum), P losses were much greater from the catchment with more poorly drained soils (0.7 kg ha-1 yr-1) than from the catchment with more freely drained soils (0.2 kg ha-1 yr-1). This paper considers the factors controlling P loss in the two catchments (farm nutrient management, soils, topography and hydrology) to explain the differences between the two catchments and the spatio-temporal variability observed. Agricultural and non-agricultural point sources, in addition to diffuse agricultural sources, are considered. Although both catchments are subject to the same NAP measures, the outcomes, in terms of both P loads and concentrations, showed that inter-annual hydrological patterns and inter-catchment hydrological properties are critical. This

  7. Trends in stream nitrogen concentrations for forested reference catchments across the USA

    Science.gov (United States)

    A. Argerich; S.L. Johnson; S.D. Sebestyen; C.C. Rhoades; E. Greathouse; J.D. Knoepp; M.B. Adams; G.E. Likens; J.L. Campbell; W.H. McDowell; F.N. Scatena; G.G. Ice

    2013-01-01

    To examine whether stream nitrogen concentrations in forested reference catchments have changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr of data collected from 22 catchments at seven USDA Forest Service Experimental Forests. Trends in stream nitrogen presented high spatial variability both among catchments at a site and among...

  8. Monitoring the Dynamics of Water Flow at a High-Mountain Permafrost Site Using Electrical Self-Potential Measurements

    Science.gov (United States)

    Kemna, A.; Weigand, M.; Wagner, F.; Hilbich, C.; Hauck, C.

    2016-12-01

    Flow of (liquid) water plays a crucial role in the dynamics of coupled thermo-hydro-mechanical processes in terrestrial permafrost systems. To better understand these processes in the active layer of permafrost regions, with the ultimate goal of adequately incorporating them in numerical models for improved scenario prediction, monitoring approaches offering high spatial and temporal resolution, areal coverage, and especially sensitivity to subsurface water flow, are highly desired. This particularly holds for high-mountain slopes, where strong variability in topography, precipitation, and snow cover, along with significant subsurface soil/rock heterogeneity, gives rise to complex spatio-temporal patterns of water flow during seasonal thawing and freezing periods. The electrical self-potential (SP) method is well known to, in theory, meeting the above monitoring demands by measuring the electrical streaming potential which is generated at the microscopic scale when water flows along electrically non-neutral interfaces. Despite its inherent sensitivity to subsurface water flow, the SP method has not yet been used for the monitoring of high-mountain permafrost sites. We here present first results from an SP monitoring survey conducted at the Schilthorn (2970 m asl) in the Bernese Alps, Switzerland, where SP data have been collected since September 2013 at a sampling rate of 10 min on a permanently installed array of 12 non-polarizing electrodes covering an area of 35 m by 15 m. While the SP time series exhibit systematic daily variations, with part of the signal clearly correlated with temperature, in particular in the snow-free periods, the largest temporal changes in the SP signal occur in spring, when the snow cover melts and thawing sets on in the active layer. The period of higher temporal SP variations continues until autumn, when the signal gradually returns to relatively low variations, coinciding with the freezing of the ground. Our results suggest that the

  9. Climate Change and Soil Erosion- Results of Comparative Model Simulations with high resoluted precipitation data for a catchment in Saxony/Germany

    Science.gov (United States)

    Michael, Anne; Schmidt, Juergen; Deutschlaender, Thomas; Enke, Wolfgang; Malitz, Gabriele

    2010-05-01

    Most available climate models produce at best mean hourly or daily precipitation data, whereas erosion is always the result of extreme but short time events, lasting normally not longer than a few hours. The frequency and intensity of these extreme events are expected to increase in some regions in Saxony/Germany which could lead to increased erosion rates. To explore these processes, the impact of expected increase in precipitation intensities as well as expected changes in land use (e.g. fruit rotation, change of phenology) on soil loss are to be considered. The use of a new method for the projection of meteorological time series and their extremes using global climate simulations (ENKE 2003, 2005) permits for the first time an approximation of future soil loss. This research is based on simulated, high resolution data (5min sums) for extreme rainfall events in the period of 2031-2050, which reproduces the mean frequency, intensity and duration of future events with high precipitation intensities relevant to erosion within the investigated seasonal period from June to August. The simulations are performed for one exemplary catchment area in Saxony, based on the EROSION 3D model (SCHMIDT et al., 1997), which is a process-based soil erosion model for simulating soil erosion and deposition by water. Simulated precipitation for the 2031-2050 time period is used to model soil loss, and results are compared to soil loss based on 20 year of measured precipitation from 1981 to 2000. The simulation results allow the impacts of climate change on erosion rates to be quantified by comparing current climate with predicted, future climate. Expected changes in land use due to influences of shifted harvest are taken into account as exemplary scenarios.

  10. Spatial Patterns of Atmospherically Deposited Organic Contaminants at High-Elevation in the Southern Sierra Nevada Mountains, California, USA

    Science.gov (United States)

    Bradford, David F.; Stanley, Kerri; McConnell, Laura L.; Tallent-Halsell, Nita G.; Nash, Maliha S.; Simonich, Staci M.

    2011-01-01

    Atmospherically deposited contaminants in the Sierra Nevada mountains of California, USA have been implicated as adversely affecting amphibians and fish, yet little is known about the distributions of contaminants within the mountains, particularly at high elevation. We tested the hypothesis that contaminant concentrations in a high-elevation portion of the Sierra Nevada decrease with distance from the adjacent San Joaquin Valley. We sampled air, sediment, and tadpoles twice at 28 water bodies in 14 dispersed areas in Sequoia and Kings Canyon National Parks (2785 – 3375 m elevation; 43 – 82 km from Valley edge). We detected up to 15 chemicals frequently in sediment and tadpoles, including current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Only β-endosulfan was found frequently in air. Concentrations of all chemicals detected were very low, averaging in the parts-per-billion range or less in sediment and tadpoles, and on the order of 10 pg/m3 for β-endosulfan in air. Principal components analysis indicated that chemical compositions were generally similar among sites, suggesting that chemical transport patterns were likewise similar among sites. In contrast, transport processes did not appear to strongly influence concentration differences among sites because variation in concentrations among nearby sites was high relative to sites far from each other. Moreover, a general relationship for concentrations as a function of distance from the valley was not evident across chemical, medium, and time. Nevertheless, concentrations for some chemical/medium/time combinations showed significant negative relationships with metrics for distance from the Valley. However, the magnitude of these distance effects among high-elevation sites was small relative to differences found in other studies between the valley edge and the nearest high-elevation sites. PMID:20821540

  11. Spatial patterns of atmospherically deposited organic contaminants at high elevation in the southern Sierra Nevada mountains, California, USA.

    Science.gov (United States)

    Bradford, David F; Stanley, Kerri; McConnell, Laura L; Tallent-Halsell, Nita G; Nash, Maliha S; Simonich, Staci M

    2010-05-01

    Atmospherically deposited contaminants in the Sierra Nevada mountains of California, USA have been implicated as adversely affecting amphibians and fish, yet little is known about the distributions of contaminants within the mountains, particularly at high elevation. The hypothesis that contaminant concentrations in a high-elevation portion of the Sierra Nevada decrease with distance from the adjacent San Joaquin Valley was tested. Air, sediment, and tadpoles were sampled twice at 28 water bodies in 14 dispersed areas in Sequoia and Kings Canyon National Parks (2,785-3,375 m elevation; 43-82 km from Valley edge). Up to 15 chemicals were detected frequently in sediment and tadpoles, including current- and historic-use pesticides, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons. Only beta-endosulfan was found frequently in air. Concentrations of all chemicals detected were very low, averaging in the parts-per-billion range or less in sediment and tadpoles, and on the order of 10 pg/m3 for beta-endosulfan in air. Principal components analysis indicated that chemical compositions were generally similar among sites, suggesting that chemical transport patterns were likewise similar among sites. In contrast, transport processes did not appear to strongly influence concentration differences among sites, because variation in concentrations among nearby sites was high relative to sites far from each other. Moreover, a general relationship for concentrations as a function of distance from the valley was not evident across chemical, medium, and time. Nevertheless, concentrations for some chemical/medium/time combinations showed significant negative relationships with metrics for distance from the Valley. However, the magnitude of these distance effects among high-elevation sites was small relative to differences found in other studies between the valley edge and the nearest high-elevation sites. Copyright (c) 2010 SETAC.

  12. Discernibility of Burial Mounds in High-Resolution X-Band SAR Images for Archaeological Prospections in the Altai Mountains

    Directory of Open Access Journals (Sweden)

    Timo Balz

    2016-09-01

    Full Text Available The Altai Mountains are a heritage-rich archaeological landscape with monuments in almost every valley. Modern nation state borders dissect the region and limit archaeological landscape analysis to intra-national areas of interest. Remote sensing can help to overcome these limitations. Due to its high precision, Synthetic Aperture Radar (SAR data can be a very useful tool for supporting archaeological prospections, but compared to optical imagery, the detectability of sites of archaeological interest is limited. We analyzed the limitations of SAR using TerraSAR-X images in different modes. Based on ground truth, the discernibility of burial mounds was analyzed in different SAR acquisition modes. We show that very-high-resolution TerraSAR-X staring spotlight images are very well suited for the task, with >75% of the larger mounds being discernible, while in images with a lower spatial resolution only a few large sites can be detected, at rates below 50%.

  13. Thermal regime of soils in the atlantic high mountain. The central massiff of Picos de Europa (Spain)

    Science.gov (United States)

    Pisabarro, Alfonso; Serrano, Enrique; José González Trueba, Juan; Pellitero, Ramón

    2015-04-01

    The study of ground thermal regime has got large interest because determine significant geomorphological processes, particularly in the high mountain where do not exist vegetal cover on the ground. Picos de Europa massifs is located in the North of the Iberian Peninsula (43°18'to 43°7'N and 5°7' to 4°36'W, Spain). It is a wet and temperate high mountain environment characterized by the presence of calcareous rock, featured by karst processes and Pleistocene glaciers. The aim of this work is analyse the thermal behavior of ground along the year at different altitudes and know limits of ice presence on the ground to differentiate stages without ice, with seasonal ice or potential permafrost. Temperature data were obtained by 12 thermal micro sensors I-Bottom and UTL-Geotest AG data-logger with centesimal accuracy undertaken to 5-10 cm depth. Micro sensors distribution vary between 1110 and 2535 m a.s.l. exploiting the sites with best topoclimatic terms in order to obtain the coldest records like ancient glaciers. The period of recordings was 2003-2007. It was enough to obtain parameters like annual ground medium temperatures, freeze and thaw cycles, freeze index or number of months with temperatures below zero. Thermal phases on the ground have been obtained. The thermal regime varies according topoclimatic conditions in the sites above cryonival stage (above 1800 m a.s.l.). It was possible to determinate four phases; highest temperatures, autumn change, winter isotherm and melt. The winter isotherm is the longest phase (6-10 months) due to the intense snowfall. During this period do not exist thermal daily amplitude and the minimum and maximum temperatures are similar; always into the interval (-0.1°C to 0°C). However there are sites where the cold is enough to break the wintry isotherm during several days with records around -6°C. The days with freeze and thaw cycles are scarce and concentrated in autumn during periods without snow cover. Results show that

  14. High-resolution observations of the near-surface wind field over an isolated mountain and in a steep river canyon

    Science.gov (United States)

    B. W. Butler; N. S. Wagenbrenner; J. M. Forthofer; B. K. Lamb; K. S. Shannon; D. Finn; R. M. Eckman; K. Clawson; L. Bradshaw; P. Sopko; S. Beard; D. Jimenez; C. Wold; M. Vosburgh

    2015-01-01

    A number of numerical wind flow models have been developed for simulating wind flow at relatively fine spatial resolutions (e.g., 100 m); however, there are very limited observational data available for evaluating these high-resolution models. This study presents high-resolution surface wind data sets collected from an isolated mountain and a steep river canyon. The...

  15. Modelling metaldehyde in catchments: a River Thames case-study.

    Science.gov (United States)

    Lu, Q; Whitehead, P G; Bussi, G; Futter, M N; Nizzetto, L

    2017-04-19

    The application of metaldehyde to agricultural catchment areas to control slugs and snails has caused severe problems for drinking water supply in recent years. In the River Thames catchment, metaldehyde has been detected at levels well above the EU and UK drinking water standards of 0.1 μg l-1 at many sites across the catchment between 2008 and 2015. Metaldehyde is applied in autumn and winter, leading to its increased concentrations in surface waters. It is shown that a process-based hydro-biogeochemical transport model (INCA-contaminants) can be used to simulate metaldehyde transport in catchments from areas of application to the aquatic environment. Simulations indicate that high concentrations in the river system are a direct consequence of excessive application rates. A simple application control strategy for metaldehyde in the Thames catchment based on model results is presented.

  16. Riverine dissolved carbon concentration and yield in subtropical catchments, Taiwan

    Science.gov (United States)

    Chen, Pei-Hao; Shih, Yu-ting; Huang, -Chuan, Jr.

    2017-04-01

    Dissolved carbon is not highly correlated to carbon cycle, but also a critical water quality indicator and affected by interaction of terrestrial and aquatic environment at catchment scale. However, the rates and extent of the dissolved carbon export are still poorly understood and scarcely quantified especially for typhoon events. In this study, regular and events' data of riverine dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) were monitored to estimate the export. Meanwhile, the hydrological model and mixing model were used for determination of DOC and DIC flow pathways at 3 sites of Tsengwen reservoir in southern Taiwan in 2014-2015. Results showed that the mean DOC concentration was 1.5 - 2.2 mg l-1 (flow weighted) without seasonal variation. The average DOC yield was 3.1 ton-C km-2 yr-1. On the other hand, DIC concentration ranged from 15 to 25.8 mg l-1, but DIC concentration in dry season was higher than wet season. Mean annual DIC yield was 51 ton-C km-2 yr-1. The export-ratio of DOC:DIC was 1:16.5, which was extremely lower than that of worldwide large rivers (DOC:DIC=1:4.5 in average) and other mountainous rivers (DOC:DIC=1:4.6 in average). Both DOC and DIC concentration showed the dramatically discrepant change in typhoon events. The DOC concentration increased to 4-8 folds rapidly before the flood peak. However, DIC concentration was diluted to one third with discharge simultaneously and returned slowly to base concentration in more than a week. According to the hydrological model, events contributed 14.6% of the annual discharge and 21.9% and 11.1% of DOC and DIC annual flux, respectively. Furthermore, 68.9% of events' discharge derived from surface runoff which carried out 91.3% of DOC flux and 51.1% of DIC flux. It implied that increases of surface runoff transported DOC form near soil surface, but diluted DIC concentration likely implied the contribution of groundwater. Our study characterized the specialty of dissolved carbon

  17. How old is upland catchment water?

    Science.gov (United States)

    Hofmann, Harald; Cartwright, Ian; Morgenstern, Uwe; Gilfedder, Benjamin

    2014-05-01

    Understanding the dynamics of water supply catchments is an essential part of water management. Upland catchments provide a continuous, reliable source of high quality water not only for some of the world's biggest cities, but also for agriculture and industry. Headwater streams control river flow in lowland agricultural basins as the majority of river discharge emerges from upland catchments. Many rivers are perennial and flow throughout the year, even during droughts. However, it is still unclear how reliable and continuous upland catchment water resources really are. Despite many efforts in upland catchment research, there is still little known about where the water is stored and how long it takes to travel through upper catchments. Resolving these questions is crucial to ensure that this resource is protected from changing land use and to estimate potential impacts from a changing climate. Previous research in this important area has been limited by existing measurement techniques. Knowledge to date has relied heavily on the use of variation in stable isotope signals to estimate the age and origin of water from upland catchments. The problem with relying on these measures is that as the water residence time increases, the variation in the stable isotope signal decreases. After a maximum period of four years, no variation can be detected This means that to date, the residence time in upland catchments is likely to have been vastly underestimated. Consequently, the proportion of water flow out of upland river catchments to the total river flow is also underestimated. Tritium (3H) combines directly with water molecules and enters the flow paths with the infiltrating water. Its half-life (12.32 years) makes it ideal to describe residence times in upper catchment reservoirs as it can theoretically measure water up to about 150 years old. The bomb pulse peak in the southern hemisphere was several orders of magnitude lower than in the northern hemisphere. Hence the

  18. Relationships among environmental variables and distribution of tree species at high elevation in the Olympic Mountains

    Science.gov (United States)

    Woodward, Andrea

    1998-01-01

    Relationships among environmental variables and occurrence of tree species were investigated at Hurricane Ridge in Olympic National Park, Washington, USA. A transect consisting of three plots was established down one north-and one south-facing slope in stands representing the typical elevational sequence of tree species. Tree species included subalpine fir (Abies lasiocarpa), Douglas-fir (Pseudotsuga menziesii), mountain hemlock (Tsuga mertensiana), and Pacific silver fir (Abies amabilis). Air and soil temperature, precipitation, and soil moisture were measured during three growing seasons. Snowmelt patterns, soil carbon and moisture release curves were also determined. The plots represented a wide range in soil water potential, a major determinant of tree species distribution (range of minimum values = -1.1 to -8.0 MPa for Pacific silver fir and Douglas-fir plots, respectively). Precipitation intercepted at plots depended on topographic location, storm direction and storm type. Differences in soil moisture among plots was related to soil properties, while annual differences at each plot were most often related to early season precipitation. Changes in climate due to a doubling of atmospheric CO2 will likely shift tree species distributions within, but not among aspects. Change will be buffered by innate tolerance of adult trees and the inertia of soil properties.

  19. High-levels of microplastic pollution in a large, remote, mountain lake.

    Science.gov (United States)

    Free, Christopher M; Jensen, Olaf P; Mason, Sherri A; Eriksen, Marcus; Williamson, Nicholas J; Boldgiv, Bazartseren

    2014-08-15

    Despite the large and growing literature on microplastics in the ocean, little information exists on microplastics in freshwater systems. This study is the first to evaluate the abundance, distribution, and composition of pelagic microplastic pollution in a large, remote, mountain lake. We quantified pelagic microplastics and shoreline anthropogenic debris in Lake Hovsgol, Mongolia. With an average microplastic density of 20,264 particles km(-2), Lake Hovsgol is more heavily polluted with microplastics than the more developed Lakes Huron and Superior in the Laurentian Great Lakes. Fragments and films were the most abundant microplastic types; no plastic microbeads and few pellets were observed. Household plastics dominated the shoreline debris and were comprised largely of plastic bottles, fishing gear, and bags. Microplastic density decreased with distance from the southwestern shore, the most populated and accessible section of the park, and was distributed by the prevailing winds. These results demonstrate that without proper waste management, low-density populations can heavily pollute freshwater systems with consumer plastics. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. EFFECTS OF FOG PRECIPITATION ON WATER RESOURCES AND DRINKING WATER TREATMENT IN THE JIZERA MOUNTAINS, THE CZECH REPUBLIC

    Directory of Open Access Journals (Sweden)

    Josef Křeček

    2015-07-01

    Full Text Available Water yield from catchments with a high evidence of fog or low clouds could be increased by the canopy fog drip. However, in areas with the acid atmospheric deposition, this process can lead to the decline of water quality. The aim of this study is to analyze fog related processes in headwater catchments of the Jizera Mountains (the Czech Republic with special attention to water quality and the drinking water treatment. In two years (2011-2012, the fog drip was observed by twelve passive fog collectors at transect of the Jizerka experimental catchment. Methods of space interpolation and extrapolation (ArcGis 10.2 were applied to approximate the areal atmospheric deposition of fog water, sulphur and nitrogen, in catchments of the drinking water reservoirs Josefův Důl and Souš. The mean annual fog drip from vegetation canopy was found between 88 and 106 mm (i.e. 7 to 9 percent of precipitation, and 11 to 13 percent of water yield, estimated by standard rain gauge monitoring. But, the mean annual load of sulphur and nitrogen by the fog drip was 1,975 and 1,080, kilograms per square kilometre, respectively (i.e. 55 and 48 percent of total deposition of sulphur and nitrogen, registered in the bulk. The acidification of surface waters leads to rising operational costs in the water treatment plants (liming, reduce of heavy metals, more frequent control of sand filters etc.. In a catchment scale, the additional precipitation, caused by the canopy fog drip, could be controlled by the effective watershed management (support of forests stands near the native composition with presence of deciduous trees: beech, mountain ash, or birch.

  1. Understanding hydrologic variability across Europe through catchment classification

    Directory of Open Access Journals (Sweden)

    A. Kuentz

    2017-06-01

    Full Text Available This study contributes to better understanding the physical controls on spatial patterns of pan-European flow signatures – taking advantage of large open datasets for catchment classification and comparative hydrology. Similarities in 16 flow signatures and 35 catchment descriptors were explored for 35 215 catchments and 1366 river gauges across Europe. Correlation analyses and stepwise regressions were used to identify the best explanatory variables for each signature. Catchments were clustered and analyzed for similarities in flow signature values, physiography and the combination of the two. We found the following. (i A 15 to 33 % (depending on the classification used improvement in regression model skills when combined with catchment classification versus simply using all catchments at once. (ii Twelve out of 16 flow signatures were mainly controlled by climatic characteristics, especially those related to average and high flows. For the baseflow index, geology was more important and topography was the main control for the flashiness of flow. For most of the flow signatures, the second most important descriptor is generally land cover (mean flow, high flows, runoff coefficient, ET, variability of reversals. (iii Using a classification and regression tree (CART, we further show that Europe can be divided into 10 classes with both similar flow signatures and physiography. The most dominant separation found was between energy-limited and moisture-limited catchments. The CART analyses also separated different explanatory variables for the same class of catchments. For example, the damped peak response for one class was explained by the presence of large water bodies for some catchments, while large flatland areas explained it for other catchments in the same class. In conclusion, we find that this type of comparative hydrology is a helpful tool for understanding hydrological variability, but is constrained by unknown human impacts on

  2. Understanding hydrologic variability across Europe through catchment classification

    Science.gov (United States)

    Kuentz, Anna; Arheimer, Berit; Hundecha, Yeshewatesfa; Wagener, Thorsten

    2017-06-01

    This study contributes to better understanding the physical controls on spatial patterns of pan-European flow signatures - taking advantage of large open datasets for catchment classification and comparative hydrology. Similarities in 16 flow signatures and 35 catchment descriptors were explored for 35 215 catchments and 1366 river gauges across Europe. Correlation analyses and stepwise regressions were used to identify the best explanatory variables for each signature. Catchments were clustered and analyzed for similarities in flow signature values, physiography and the combination of the two. We found the following. (i) A 15 to 33 % (depending on the classification used) improvement in regression model skills when combined with catchment classification versus simply using all catchments at once. (ii) Twelve out of 16 flow signatures were mainly controlled by climatic characteristics, especially those related to average and high flows. For the baseflow index, geology was more important and topography was the main control for the flashiness of flow. For most of the flow signatures, the second most important descriptor is generally land cover (mean flow, high flows, runoff coefficient, ET, variability of reversals). (iii) Using a classification and regression tree (CART), we further show that Europe can be divided into 10 classes with both similar flow signatures and physiography. The most dominant separation found was between energy-limited and moisture-limited catchments. The CART analyses also separated different explanatory variables for the same class of catchments. For example, the damped peak response for one class was explained by the presence of large water bodies for some catchments, while large flatland areas explained it for other catchments in the same class. In conclusion, we find that this type of comparative hydrology is a helpful tool for understanding hydrological variability, but is constrained by unknown human impacts on the water cycle and by

  3. Rates and drivers of erosion in the Southern Pyrenees: a 10Be-supported model for the Valle de la Fueva catchments

    Science.gov (United States)

    Stange, Kurt Martin; Midtkandal, Ivar; Petter Nystuen, Johan; Sohbati, Reza; Murray, Andrew Sean; Spiegel, Cornelia; Kuss, Jochen

    2017-04-01

    Intramontane basins are typical features of every mountain chain. These topographic depressions function as sediment traps during the syn- and postorogenic evolution of a range. Hence, studying their sedimentary archives and morphogenetic development may deliver important insights into the dynamics and magnitudes of erosion-sedimentation processes in mountain catchments and their susceptibility towards changing environmental conditions. Aiming at quantifying Quaternary catchment erosion rates in the Southern Pyrenees and determining the timing and driving parameters of basin excavation stages, this research project focusses on a number of adjacent watersheds in the Valle de la Fueva in Aragon, Spain. Besides providing a comprehensive OSL and 10Be-supported catchment erosion model, potential relationships of intense late stage erosion phases with watershed capture, base level changes and climatic controls are addressed. The Valle de la Fueva comprises a number of sub-catchments of the Ainsa depression - an Eocene sedimentary basin situated in the southern Pyrenean fold and thrust belt (SPFZ) which is recognized as a prime analogue for reservoir geometries and turbidite systems. The Valle de la Fueva is a highly erodible catchment, typical for the SPFZ with its shallow and deep marine strata, conglomerates and synorogenic debris. Preliminary observations revealed systems of "cut-in-fill" alluvial terraces and residual erosion surfaces - i.e. pediments and glacis that are strongly dissected by gullies and barrancos. Basin outlet canyons are deeply entrenched into the Los Molinos thrust front and represent dramatic landscape features that are relevant to the base level and opening history of the Valle de la Fueva catchments. Combining digital terrain analysis with field surveys and exposure/burial dating, first results revealed differences in stream profile gradation and incision magnitudes among several sub-catchments. Since they share a common base level, the main

  4. Essential oil composition, phytotoxic and antifungal activities of Ruta chalepensis L. leaves from High Atlas Mountains (Morocco).

    Science.gov (United States)

    Bouajaj, Sana; Romane, Abderrahmane; Benyamna, Abdennaji; Amri, Ismail; Hanana, Mohsen; Hamrouni, Lamia; Romdhane, Mehrez

    2014-01-01

    This study aimed at the determination of chemical composition of essential oil obtained by hydrodistillation, and to evaluate their phytotoxic and antifungal activities. Leaves of Ruta chalepensis L. were collected from the region of Tensift Al Haouz (High Atlas Mountains) Marrakech, Morocco. The essential oil (oil yield is 0.56%) was analysed by GC-FID and GC/MS. Twenty-two compounds were identified and accounted for 92.4% of the total oil composition. The major components were undecan-2-one (49.08%), nonan-2-one (33.15%), limonene (4.19%) and decanone (2.71%). Antifungal ability of essential oils was tested by disc agar diffusion against five plant pathogenic fungi: Fusarium proliferatum, Fusarium pseudograminearum, Fusarium culmorum, Fusarium graminearum and Fusarium polyphialidicum. The oils were also tested in vitro for herbicidal activity by determining their influence on the germination and the shoot and root growth of two weed species, Triticum durum and Phalaris canariensis L.

  5. Preliminary total-system analysis of a potential high-level nuclear waste repository at Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    Eslinger, P.W.; Doremus, L.A.; Engel, D.W.; Miley, T.B.; Murphy, M.T.; Nichols, W.E.; White, M.D. [Pacific Northwest Lab., Richland, WA (United States); Langford, D.W.; Ouderkirk, S.J. [Westinghouse Hanford Co., Richland, WA (United States)

    1993-01-01

    The placement of high-level radioactive wastes in mined repositories deep underground is considered a disposal method that would effectively isolate these wastes from the environment for long periods of time. This report describes modeling performed at PNL for Yucca Mountain between May and November 1991 addressing the performance of the entire repository system related to regulatory criteria established by the EPA in 40 CFR Part 191. The geologic stratigraphy and material properties used in this study were chosen in cooperation with performance assessment modelers at Sandia National Laboratories (SNL). Sandia modeled a similar problem using different computer codes and a different modeling philosophy. Pacific Northwest Laboratory performed a few model runs with very complex models, and SNL performed many runs with much simpler (abstracted) models.

  6. A Treatment Train Approach To Catchment Management

    Science.gov (United States)

    Barber, Nick; Quinn, Paul; Org, EdenDTC

    2017-04-01

    The treatment train approach has been attempted in a 1.6km2 catchment in the River Eden as part of the UK Demonstration Test Catchment Project. The catchment is one of three detailed study catchments of 10km2 that are investigating diffuse pollution losses from an intense grassland farming system. The catchment is very susceptible to saturation and high losses of fine sediment and phosphorus in storm events. The poster will show how a sequence of mitigation features that target nutrient sources and flow pathways can reduce nutrient losses. 5 features have been installed from farmyard runoff control, along polluting tracks and sediment traps in the farm ditch network. Together the features can slow, store and trap sediment and pollutants. The potential to have further impacts on flood generation and drought mitigation are also being studied. Although the features are currently small in size the ability to directly reduce pollution can be demonstrated. Hence, the potential to scale up these features to a broader catchment scale can be explored and the likely costs and benefits can be simulated. This work builds upon similar work addressing flood control features, sediment trapping on farms and methods for the direct mitigation of fast polluting pathways often referred to as Nature Based Solutions. The designs and construction of the completed features will be shown in the poster. Early results show that the combined effect of the 5 features can significantly impact on sediment and pollution during storm events. The specific yield of the impact was 42 kg of suspended sediment/ha 0.06 kg P/ha of P trapped and 0.16 kg of N/ha. This mitigation impact is derived from an area of only 0.02% of the catchment. The potential to increase the mitigated area is thus large. Payment schemes for farmers could encourage the take up the of these methods and future maintenance regimes for managing the features would also have to be created. However, the potential to mitigate fast

  7. Assessing intraspecific variation in effective dispersal along an altitudinal gradient: a test in two Mediterranean high-mountain plants.

    Directory of Open Access Journals (Sweden)

    Carlos Lara-Romero

    Full Text Available BACKGROUND: Plant recruitment depends among other factors on environmental conditions and their variation at different spatial scales. Characterizing dispersal in contrasting environments may thus be necessary to understand natural intraspecific variation in the processes underlying recruitment. Silene ciliata and Armeria caespitosa are two representative species of cryophilic pastures above the tree line in Mediterranean high mountains. No explicit estimations of dispersal kernels have been made so far for these or other high-mountain plants. Such data could help to predict their dispersal and recruitment patterns in a context of changing environments under ongoing global warming. METHODS: We used an inverse modelling approach to analyse effective seed dispersal patterns in five populations of both Silene ciliata and Armeria caespitosa along an altitudinal gradient in Sierra de Guadarrama (Madrid, Spain. We considered four commonly employed two-dimensional seedling dispersal kernels exponential-power, 2Dt, WALD and log-normal. KEY RESULTS: No single kernel function provided the best fit across all populations, although estimated mean dispersal distances were short (<1 m in all cases. S. ciliata did not exhibit significant among-population variation in mean dispersal distance, whereas significant differences in mean dispersal distance were found in A. caespitosa. Both S. ciliata and A. caespitosa exhibited among-population variation in the fecundity parameter and lacked significant variation in kernel shape. CONCLUSIONS: This study illustrates the complexity of intraspecific variation in the processes underlying recruitment, showing that effective dispersal kernels can remain relatively invariant across populations within particular species, even if there are strong variations in demographic structure and/or physical environment among populations, while the invariant dispersal assumption may not hold for other species in the same environment

  8. Analogues to features and processes of a high-level radioactive waste repository proposed for Yucca Mountain, Nevada

    Science.gov (United States)

    Simmons, Ardyth M.; Stuckless, John S.; with a Foreword by Abraham Van Luik, U.S. Department of Energy

    2010-01-01

    Natural analogues are defined for this report as naturally occurring or anthropogenic systems in which processes similar to those expected to occur in a nuclear waste repository are thought to have taken place over time periods of decades to millennia and on spatial scales as much as tens of kilometers. Analogues provide an important temporal and spatial dimension that cannot be tested by laboratory or field-scale experiments. Analogues provide one of the multiple lines of evidence intended to increase confidence in the safe geologic disposal of high-level radioactive waste. Although the work in this report was completed specifically for Yucca Mountain, Nevada, as the proposed geologic repository for high-level radioactive waste under the U.S. Nuclear Waste Policy Act, the applicability of the science, analyses, and interpretations is not limited to a specific site. Natural and anthropogenic analogues have provided and can continue to provide value in understanding features and processes of importance across a wide variety of topics in addressing the challenges of geologic isolation of radioactive waste and also as a contribution to scientific investigations unrelated to waste disposal. Isolation of radioactive waste at a mined geologic repository would be through a combination of natural features and engineered barriers. In this report we examine analogues to many of the various components of the Yucca Mountain system, including the preservation of materials in unsaturated environments, flow of water through unsaturated volcanic tuff, seepage into repository drifts, repository drift stability, stability and alteration of waste forms and components of the engineered barrier system, and transport of radionuclides through unsaturated and saturated rock zones.

  9. Insights in nutrient sources and transport from high-frequency monitoring at the outlet pumping station of an agricultural lowland polder catchment

    Science.gov (United States)

    Rozemeijer, J.; Van der Grift, B.; Broers, H. P.; Berendrecht, W.; Oste, L.; Griffioen, J.

    2015-12-01

    In this study, we present new insights in nutrient sources and transport processes in an agricultural-dominated lowland water system based on high-frequency monitoring technology. Starting in October 2014, we have collected semi-continuous measurements of the TP and NO3 concentrations, conductivity and water temperature at a large scale pumping station at the outlet of a 576 km2 polder catchment. The semi-continuous measurements complement a water quality monitoring program at six locations within the drainage area based on conventional monthly or biweekly grab sampling. The NO3 and TP concentrations at the pumping station varied between 0.5 and 10 mgN/L and 0.1 and 0.5 mgP/L. The seasonal trends and short scale concentration dynamics clearly indicated that most of the NO3 loads at the pumping station originated from subsurface drain tubes that were active after intensive rainfall events during the winter months. A transfer function-noise model of hourly NO3 concentrations reveals that a large part of the dynamics in NO3 concentrations during the winter months can be predicted using rainfall data. In February however, NO3 concentrations were higher than predicted due to direct losses after the first manure application. The TP concentration almost doubled during operation of the pumping station. This highlights resuspension of particulate P from channel bed sediments induced by the higher flow velocities during pumping. Rainfall events that caused peaks in NO3 concentrations did not result in TP concentration peaks. Direct effects of run-off, with an association increase in the TP concentration and decrease of the NO3concentration, was only observed during rainfall event at the end of a freeze-thaw cycle. The high-frequency monitoring at the outlet of an agricultural-dominated lowland water system in combination with low-frequency monitoring within the area provided insight in nutrient sources and transport processes that are highly relevant for water quality

  10. Catchment areas for public transport

    DEFF Research Database (Denmark)

    Andersen, Jonas Lohmann Elkjær; Landex, Alex

    2008-01-01

    In the planning of public transport catchment areas of stops are often included to estimate potential number of travellers. There are different approaches to GIS-based catchment area analyses depending on the desired level of detail. The Circular Buffer approach is the fundamental, but also....../from stations. The article also shows how the refinement of the Service Area approach with additional time resistance results in smaller catchment areas when the feeder routes cross stairs. It is concluded that GIS-based catchment area analyses are a multiple decision support tool for planning of public...

  11. Modelling soil erosion in a head catchment of Jemma Basin on the Ethiopian highlands

    Science.gov (United States)

    Cama, Mariaelena; Schillaci, Calogero; Kropáček, Jan; Hochschild, Volker; Maerker, Michael

    2017-04-01

    Soil erosion represents one of the most important global issues with serious effects on agriculture and water quality especially in developing countries such as Ethiopia where rapid population growth and climatic changes affect wide mountainous areas. The catchment of Andit-Tid is a head catchment of Jemma Basin draining to the Blue Nile (Central Ethiopia). It is located in an extremely variable topographical environment and it is exposed to high degradation dynamics especially in the lower part of the catchment. The increasing agricultural activity and grazing, lead to an intense use of the steep slopes which altered the soil structure. As a consequence, water erosion processes accelerated leading to the evolution of sheet erosion, gullies and badlands. This study is aimed at a geomorphological assessment of soil erosion susceptibility. First, a geomorphological map is generated using high resolution digital elevation model (DEM) derived from high resolution stereoscopic satellite data, multispectral imagery from Rapid Eye satellite system . The map was then validated by a detailed field survey. The final maps contains three inventories of landforms: i) sheet, ii) gully erosion and iii) badlands. The water erosion susceptibility is calculated with a Maximum Entropy approach. In particular, three different models are built using the three inventories as dependent variables and a set of spatial attributes describing the lithology, terrain, vegetation and land cover from remote sensing data and DEMs as independent variables. The single susceptibility maps for sheet, gully erosion as well as badlands showed good to excellent predictive performances. Moreover, we reveal and discuss the importance of different sets of variables among the three models. In order to explore the mutual overlap of the three susceptibility maps we generated a combined map as color composite whereas each color represents one component of water erosion. The latter map yield a useful information

  12. Pre-construction geologic section along the cross drift through the potential high-level radioactive waste repository, Yucca Mountain, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Potter, C.J.; Day, W.C.; Sweetkind, D.S. [Geological Survey, Denver, CO (United States); Juan, C.S.; Drake, R.M. II [Pacific Western Technologies, Ltd., Denver, CO (United States)

    1998-12-31

    As part of the Site Characterization effort for the US Department of Energy`s Yucca Mountain Project, tunnels excavated by tunnel boring machines provide access to the volume of rock that is under consideration for possible underground storage of high-level nuclear waste beneath Yucca Mountain, Nevada. The Exploratory Studies Facility, a 7.8-km-long, 7.6-m-diameter tunnel, has been excavated, and a 2.8-km-long, 5-m-diameter Cross Drift will be excavated in 1998 as part of the geologic, hydrologic and geotechnical evaluation of the potential repository. The southwest-trending Cross Drift branches off of the north ramp of the horseshoe-shaped Exploratory Studies Facility. This report summarizes an interpretive geologic section that was prepared for the Yucca Mountain Project as a tool for use in the design and construction of the Cross Drift.

  13. Monitoring of vegetation impact due to trampling on Cadillac Mountain summit using high spatial resolution remote sensing data sets.

    Science.gov (United States)

    Kim, Min-Kook; Daigle, John J

    2012-11-01

    Cadillac Mountain--the highest peak along the eastern seaboard of the United States--is a major tourist destination in Acadia National Park, Maine. Managing vegetation impact due to trampling on the Cadillac Mountain summit is extremely challenging because of the large number of visitors and the general open nature of landscape in this fragile subalpine environmental setting. Since 2000, more intensive management strategies--based on placing physical barriers and educational messages for visitors--have been employed to protect threatened vegetation, decrease vegetation impact, and enhance vegetation recovery in the vicinity of the summit loop trail. The primary purpose of this study was to evaluate the effect of the management strategies employed. For this purpose, vegetation cover changes between 2001 and 2007 were detected using multispectral high spatial resolution remote sensing data sets. A normalized difference vegetation index was employed to identify the rates of increase and decrease in the vegetation areas. Three buffering distances (30, 60, and 90 m) from the edges of the trail were used to define multiple spatial extents of the site, and the same spatial extents were employed at a nearby control site that had no visitors. No significant differences were detected between the mean rates of vegetation increase and decrease at the experimental site compared with a nearby control site in the case of a small spatial scale (≤30 m) comparison (in all cases P > 0.05). However, in the medium (≤60 m) and large (≤90 m) spatial scales, the rates of increased vegetation were significantly greater and rates of decreased vegetation significantly lower at the experimental site compared with the control site (in all cases P vegetation at the site level. Management implications are explored in terms of the spatial strategies used to decrease the impact of trampling on vegetation.

  14. Experimental measurements for improved understanding and simulation of snowmelt events in the Western Tatra Mountains

    Directory of Open Access Journals (Sweden)

    Krajčí Pavel

    2016-12-01

    Full Text Available Snow accumulation and melt are highly variable. Therefore, correct modeling of spatial variability of the snowmelt, timing and magnitude of catchment runoff still represents a challenge in mountain catchments for flood forecasting. The article presents the setup and results of detailed field measurements of snow related characteristics in a mountain microcatchment (area 59 000 m2, mean altitude 1509 m a. s. l. in the Western Tatra Mountains, Slovakia obtained in winter 2015. Snow water equivalent (SWE measurements at 27 points documented a very large spatial variability through the entire winter. For instance, range of the SWE values exceeded 500 mm at the end of the accumulation period (March 2015. Simple snow lysimeters indicated that variability of snowmelt and discharge measured at the catchment outlet corresponded well with the rise of air temperature above 0°C. Temperature measurements at soil surface were used to identify the snow cover duration at particular points. Snow melt duration was related to spatial distribution of snow cover and spatial patterns of snow radiation. Obtained data together with standard climatic data (precipitation and air temperature were used to calibrate and validate the spatially distributed hydrological model MIKE-SHE. The spatial redistribution of input precipitation seems to be important for modeling even on such a small scale. Acceptable simulation of snow water equivalents and snow duration does not guarantee correct simulation of peakflow at short-time (hourly scale required for example in flood forecasting. Temporal variability of the stream discharge during the snowmelt period was simulated correctly, but the simulated discharge was overestimated.

  15. YUCCA MOUNTAIN SITE DESCRIPTION

    Energy Technology Data Exchange (ETDEWEB)

    A.M. Simmons

    2004-04-16

    The ''Yucca Mountain Site Description'' summarizes, in a single document, the current state of knowledge and understanding of the natural system at Yucca Mountain. It describes the geology; geochemistry; past, present, and projected future climate; regional hydrologic system; and flow and transport within the unsaturated and saturated zones at the site. In addition, it discusses factors affecting radionuclide transport, the effect of thermal loading on the natural system, and tectonic hazards. The ''Yucca Mountain Site Description'' is broad in nature. It summarizes investigations carried out as part of the Yucca Mountain Project since 1988, but it also includes work done at the site in earlier years, as well as studies performed by others. The document has been prepared under the Office of Civilian Radioactive Waste Management quality assurance program for the Yucca Mountain Project. Yucca Mountain is located in Nye County in southern Nevada. The site lies in the north-central part of the Basin and Range physiographic province, within the northernmost subprovince commonly referred to as the Great Basin. The basin and range physiography reflects the extensional tectonic regime that has affected the region during the middle and late Cenozoic Era. Yucca Mountain was initially selected for characterization, in part, because of its thick unsaturated zone, its arid to semiarid climate, and the existence of a rock type that would support excavation of stable openings. In 1987, the United States Congress directed that Yucca Mountain be the only site characterized to evaluate its suitability for development of a geologic repository for high-level radioactive waste and spent nuclear fuel.

  16. Comparison of hydrochemistry and organic compound transport in two non-glaciated high Arctic catchments with a permafrost regime (Bellsund Fjord, Spitsbergen).

    Science.gov (United States)

    Lehmann-Konera, Sara; Franczak, Łukasz; Kociuba, Waldemar; Szumińska, Danuta; Chmiel, Stanisław; Polkowska, Żaneta

    2018-02-01

    An increase in air temperature related to climate change results in the retreat of glaciers, the degradation of permafrost, and the expansion of glacier-free areas in the polar regions. All these processes lead to changes in the Arctic landscape. They influence the hydrochemistry of streams and rivers fed by glaciers and thawing permafrost. In this study, we examine eighty two water samples from two non-glaciated catchments with snow-permafrost regime: the Tyvjobekken Creek and the Reindeer Creek (NW Wedel-Jarlsberg Land, Spitsbergen). We cover hydrometeorological measurements, fluctuations of physicochemical parameters (pH, specific electrolytic conductivity (SEC)), and the presence of selected organic compounds (dissolved organic carbon (DOC), formaldehyde (HCHO), ∑phenols). The obtained levels of DOC (0.061-0.569mgCL-1) and HCHO (melting permafrost as a rich source of terrestrial organic carbon and organic pollutants, as well as the impact of rainfall on surface water chemistry. It was found that fluctuations of physicochemical indices (pH, SEC, DOC) were related to changes in mean daily discharge of Reindeer Creek (0.012-0.034m3s-1) and Tyvjobekken Creek (0.011-0.015m3s-1) (r>0.40). The Tyvjobekken Creek catchment, in contrast to Reindeer Creek catchment, turned out to be resistant to rapid changes in meteorological conditions (rpermafrost thawing, calcium carbonate dissolution, and biogeochemical "breathing" of soils proved to be crucial for the development of water chemistry. In conclusion, the surface water chemistry of the Reindeer Creek was found to result from the mutual influence of hydrometeorological indices and the biogeochemical environment of the catchment. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Integration of rainfall/runoff and geomorphological analyses flood hazard in small catchments: case studies from the southern Apennines (Italy)

    Science.gov (United States)

    Palumbo, Manuela; Ascione, Alessandra; Santangelo, Nicoletta; Santo, Antonio

    2017-04-01

    We present the first results of an analysis of flood hazard in ungauged mountain catchments that are associated with intensely urbanized alluvial fans. Assessment of hydrological hazard has been based on the integration of rainfall/runoff modelling of drainage basins with geomorphological analysis and mapping. Some small and steep, ungauged mountain catchments located in various areas of the southern Apennines, in southern Italy, have been chosen as test sites. In the last centuries, the selected basins have been subject to heavy and intense precipitation events, which have caused flash floods with serious damages in the correlated alluvial fan areas. Available spatial information (regional technical maps, DEMs, land use maps, geological/lithological maps, orthophotos) and an automated GIS-based procedure (ArcGis tools and ArcHydro tools) have been used to extract morphological, hydrological and hydraulic parameters. Such parameters have been used to run the HEC (Hydrologic Engineering Center of the US Army Corps of Engineers) software (GeoHMS, GeoRAS, HMS and RAS) based on rainfall-runoff models, which have allowed the hydrological and hydraulic simulations. As the floods occurred in the studied catchments have been debris flows dominated, the solid load simulation has been also performed. In order to validate the simulations, we have compared results of the modelling with the effects produced by past floods. Such effects have been quantified through estimations of both the sediment volumes within each catchment that have the potential to be mobilised (pre-event) during a sediment transfer event, and the volume of sediments delivered by the debris flows at basins' outlets (post-event). The post-event sediment volume has been quantified through post-event surveys and Lidar data. Evaluation of the pre-event sediment volumes in single catchments has been based on mapping of sediment storages that may constitute source zones of bed load transport and debris flows. For

  18. Quantification of optic disc edema during exposure to high altitude shows no correlation to acute mountain sickness.

    Directory of Open Access Journals (Sweden)

    Gabriel Willmann

    Full Text Available BACKGROUND: The study aimed to quantify changes of the optic nerve head (ONH during exposure to high altitude and to assess a correlation with acute mountain sickness (AMS. This work is related to the Tuebingen High Altitude Ophthalmology (THAO study. METHODOLOGY/PRINCIPAL FINDINGS: A confocal scanning laser ophthalmoscope (cSLO, Heidelberg Retina Tomograph, HRT3® was used to quantify changes at the ONH in 18 healthy participants before, during and after rapid ascent to high altitude (4559 m. Slitlamp biomicroscopy was used for clinical optic disc evaluation; AMS was assessed with Lake Louise (LL and AMS-cerebral (AMS-c scores; oxygen saturation (SpO₂ and heart rate (HR were monitored. These parameters were used to correlate with changes at the ONH. After the first night spent at high altitude, incidence of AMS was 55% and presence of clinical optic disc edema (ODE 79%. Key stereometric parameters of the HRT3® used to describe ODE (mean retinal nerve fiber layer [RNFL] thickness, RNFL cross sectional area, optic disc rim volume and maximum contour elevation changed significantly at high altitude compared to baseline (p<0.05 and were consistent with clinically described ODE. All changes were reversible in all participants after descent. There was no significant correlation between parameters of ODE and AMS, SpO₂ or HR. CONCLUSIONS/SIGNIFICANCE: Exposure to high altitude leads to reversible ODE in the majority of healthy subjects. However, these changes did not correlate with AMS or basic physiologic parameters such as SpO₂ and HR. For the first time, a quantitative approach has been used to assess these changes during acute, non-acclimatized high altitude exposure. In conclusion, ODE presents a reaction of the body to high altitude exposure unrelated to AMS.

  19. Assessing transhumance corridors on high mountain environments by least cost path analysis: the case of yak herds in Gilgit-Baltistan, Pakistan.

    Science.gov (United States)

    Hashmi, Maaz Maqsood; Frate, Ludovico; Nizami, Syed Moazzam; Carranza, Maria Laura

    2017-09-07

    Mountain environments in the world host highly specialized flora and fauna which are vulnerable because of land use and climate change. Transhumance and other land use traditional practices are present in most of the mountains of the world, and management tools able to cope with new socioeconomic settings and environmental changes are urgently needed. During past centuries, yak (Bos grunniens) herding in Northern Pakistan involved the migration of herds to high mountain international rangelands, but the recent establishment of international borders breaks the traditional transhumance paths, promoting several ecological problems. In this paper, we propose the use of least cost path (LCP) algorithm to identify the most efficient corridors of transhumance for yak herds on northern high altitudes of Pakistan. Specifically, LCP was implemented to identify the critical grazing areas and the connecting zones to be accounted in a new management plan for the yaks in the region. The LCP analysis showed that some grazing areas are connected with several paths, whereas other areas are connected to a lesser extent. The analyses identified a set of best minimum cost paths able to guarantee local connectivity. We also delineated several medium and low efficient paths that could play a crucial role for maintaining regional connectivity which is essential for reducing the isolation of herds and the consequent inbreeding problems. The analytical framework implemented in this study allowed to (1) provide valuable information concerning the movement of yak herds in Gilgit-Baltistan, (2) identify potential corridors that are able to promote herd movement between villages and high mountain rangelands, and (3) identify critical areas for the connectivity of yaks by ranking of the potential corridors according to their length and permeability. The analysis would be extended to other transhumant herds and high mountain areas that are facing sociopolitical transformations and environmental

  20. Assessment of catchment scale connectivity in different catchments using measured suspended sediment output

    Science.gov (United States)

    Masselink, Rens; Keesstra, Saskia; Seeger, Manuel

    2014-05-01

    Recent developments in hydrology and geomorphology include the connectivity principle, which describes how different elements in a landscape are connected and how water and matter moves between these elements. So far, studies on connectivity have been mainly of a conceptual nature and have been done on a small scale, while studies that map, quantitatively establish relations, and model water and sediment transport in connectivity are rare. In this study we established a relation between change in connectivity within four catchments and the time of year by using suspended sediment data. The data were collected for four catchments in Navarra, Spain of which two catchments are dominated by forest and pasture, while the other two catchments are dominated by agriculture and have no forest. Data were collected during a 13 year period; 4 samples were taken a day at 6 hour intervals which were mixed to obtain a daily average suspended sediment concentration. This was then converted into daily suspended sediment output using the measured total daily discharge. The effect of precipitation on the sediment output data was minimized by using an antecedent precipitation index (API), which consists of the precipitation of the current day added by the precipitation of the previous 14 days, where the influence of the previous days decays exponentially with time. The daily total suspended sediment output was divided by the API, to obtain a measure for sediment output independent of precipitation. This sediment output then serves as a measure for the connectivity within the catchment. The connectivity of the four catchments throughout the years will be compared to each other and we hypothesise that the two catchments dominated by forests and pastures will change only slightly throughout the year, whereas we expect to see large differences in connectivity in the two agricultural catchments. The agricultural catchments are likely to display a highly varying connectivity throughout the

  1. On the influence of topographic, geological and cryospheric factors on rock avalanches and rockfalls in high-mountain areas

    Directory of Open Access Journals (Sweden)

    L. Fischer

    2012-01-01

    Full Text Available The ongoing debate about the effects of changes in the high-mountain cryosphere on rockfalls and rock avalanches suggests a need for more knowledge about characteristics and distribution of recent rock-slope instabilities. This paper investigates 56 sites with slope failures between 1900 and 2007 in the central European Alps with respect to their geological and topographical settings and zones of possible permafrost degradation and glacial recession. Analyses of the temporal distribution show an increase in frequency within the last decades. A large proportion of the slope failures (60% originated from a relatively small area above 3000 m a.s.l. (i.e. 10% of the entire investigation area. This increased proportion of detachment zones above 3000 m a.s.l. is postulated to be a result of a combination of factors, namely a larger proportion of high slope angles, high periglacial weathering due to recent glacier retreat (almost half of the slope failures having occurred in areas with recent deglaciation, and widespread permafrost occurrence. The lithological setting appears to influence volume rather than frequency of a slope failure. However, our analyses show that not only the changes in cryosphere, but also other factors which remain constant over long periods play an important role in slope failures.

  2. Development of an object-based classification model for mapping mountainous forest cover at high elevation using aerial photography

    Science.gov (United States)

    Lateb, Mustapha; Kalaitzidis, Chariton; Tompoulidou, Maria; Gitas, Ioannis

    2016-08-01

    Climate change and overall temperature increase results in changes in forest cover in high elevations. Due to the long life cycle of trees, these changes are very gradual and can be observed over long periods of time. In order to use remote sensing imagery for this purpose it needs to have very high spatial resolution and to have been acquired at least 50 years ago. At the moment, the only type of remote sensing imagery with these characteristics is historical black and white aerial photographs. This study used an aerial photograph from 1945 in order to map the forest cover at the Olympus National Park, at that date. An object-based classification (OBC) model was developed in order to classify forest and discriminate it from other types of vegetation. Due to the lack of near-infrared information, the model had to rely solely on the tone of the objects, as well as their geometric characteristics. The model functioned on three segmentation levels, using sub-/super-objects relationships and utilising vegetation density to discriminate forest and non-forest vegetation. The accuracy of the classification was assessed using 503 visually interpreted and randomly distributed points, resulting in a 92% overall accuracy. The model is using unbiased parameters that are important for differentiating between forest and non-forest vegetation and should be transferrable to other study areas of mountainous forests at high elevations.

  3. Long-term forest paired catchment studies: What do they tell us that landscape-level monitoring does not?

    Science.gov (United States)

    Dan Neary

    2016-01-01

    Forested catchments throughout the world are known for producing high quality water for human use. In the 20th Century, experimental forest catchment studies played a key role in studying the processes contributing to high water quality. The hydrologic processes investigated on these paired catchments have provided the science base for examining water quality...

  4. Ain't no mountain high enough: plant invasions reaching new elevations

    Science.gov (United States)

    An& iacute Pauchard; bal; Christoph Kueffer; Hansj& ouml Dietz; rg; Curtis C. Daehler; Jake Alexander; Peter J. Edwards; Ar& eacute; Jos& eacute valo; Ram& oacute; n; Lohengrin A. Cavieres; Antoine Guisan; Sylvia Haider; Gabi Jakobs; Keith McDougall; Constance I. Millar; Bridgett J. Naylor; Catherine G. Parks; Lisa J. Rew; Tim Seipel

    2009-01-01

    Most studies of invasive species have been in highly modified, lowland environments, with comparatively little attention directed to less disturbed, high-elevation environments. However, increasing evidence indicates that plant invasions do occur in these environments, which often have high conservation value and provide important ecosystem services. Over a thousand...

  5. Is diatom richness responding to catchment glaciation? A case study from Cana+9dian headwater streams

    Directory of Open Access Journals (Sweden)

    Eugen Rott

    2012-01-01

    Full Text Available Due to global change affecting glaciers worldwide, glacial streams are seen as threatened environments deserving specific scientific interest. Glacial streams from the Coast Range and Rocky Mountains in British Columbia and at the border to Alberta were investigated. In particular glacial streams and downstream sites in the Joffré Lakes Provincial Park, a near by mountain river and two large glacial streams in the Rocky Mountains (Kootenay Range, Jasper National Park were studied. Regardless of a high variability of catchment glaciation (1 to 99% thin organic biofilms with firmly attached diatom frustules of the genera Achnanthidium, Psammothidium, Encyonema, Gomphonema and fragilaroid taxa were found in all cases. In spite of fundamentally different geological conditions between the Coast Range sites and the Rocky Mountain sites, the pioneer taxon Achnanthidium minutissimum (with a slimy long ecomorph was dominating quantitatively in most of the glacier stream samples together with the rheobiontic Hannaea arcus. Individual glacier stream samples were characterized by the dominance of Achnanthidium petersenii and Gomphonema calcifugum/Encyonema latens. The diatom community analysis (cluster analysis revealed the expected separation of glacier stream sites and sites of the lower segments of the river continuum (e.g., dominance of Diatoma ehrenbergii in the mountain river. In the Joffré area, the total species richness of turbid glacial streams close to the glacier mouth was significantly lower than in the more distant sites. The two largest glacial streams in the Rocky Mountains showed divergent results with a remarkable high species richness (43 taxa at the Athabasca River origin (Columbia Icefield and low diversity in Illecillewaet river (9 km downstream the glacier mouth. From the biogeographical point of view the dominant taxa comprised mainly widespread pioneer species coping best with the unstable conditions, while the subdominant taxa

  6. Sediment tracing and use of terrestrial laser scanning (TLS) for monitoring and modelling hydrological and sedimentary processes in the Upper Guil Catchment (Queyras, French Alps)

    Science.gov (United States)

    Lissak, Candide; Fort, Monique; Fassetta, Gilles Arnaud; Malet, Jean-Philippe; Carlier, Benoit; Viel, Vincent

    2015-04-01

    In the frame of SAMCO (ANR 12 SENV-0004) project designed for mountain hazard mitigation in a context of Climate Change, one of our purposes is to understand the hydro-geomorphological specificities of French Alpine catchments. Part of our study deals with a better assessment of the sediment transfers, and adjacent sediment supply (i.e. from hillslope to channel, and from tributaries to the trunk river) during seasonal meteorological events, and major event inducing floods and/or avalanches. Our research focuses on the Guil River catchment (Queyras, Southern French Alps), prone to catastrophic floods (June 1957 (> R.I. 100 yr), June 2000 (R.I. 30 yr)...) with serious damages to infrastructure and buildings located in the valley bottoms. Such floods are characterized by considerable sediment transport from debris flow prone tributaries to downvalley, together with strong hillslope-channel connectivity. The "schistes lustrés" bedrock is an aggravating factor that explains the mobilization of huge volumes during floods (≈12,000 m3 aggraded during the June 2000 flood event). Confluences with debris flow prone tributaries are particularly sensitive areas.. For monitoring and modelling hydrological and sedimentary processes our approach is twofold: (i)> assessment of slopes contribution to sediment supply using terrestrial laser scanning (TLS), (ii) assessment of two sub-catchment contribution to the global sediment budget of the Guil river catchment using passive integrated transponder (PIT) technique. To assess coarse sediment fluxes and delivery into the main channel network, we implemented 560 tracers in 4 selected sub-catchments. To assess small sediment delivery, 1 Airborne LiDAR and 2 TLS campaigns have been performed using Optech station over 3 specific hotspots highly affected by slope erosion and largely contributing to the Guil river sediment budget. The first location corresponds to a gorge section with direct connection of hillslope to the main channel

  7. Glacier melt buffering sustains river flow in the Pamir Mountains

    Science.gov (United States)

    Pohl, Eric; Andermann, Christoff; Gloaguen, Richard

    2017-04-01

    Central Asia's water resources and agricultural practices depend on snow and glacier melts in the high mountains. The Amu Darya, the main river draining the Pamir Mountains, exemplifies the resulting seasonality in stream flow. In winter, comparably low amounts of groundwater discharge feed the streams, while the bulk of precipitation is provided and stored as snow. Successive melting of snow cover and glaciers during summer releases these stored waters to the swelling rivers. Despite a strong variability in precipitation and temperatures over the entire Pamir Mountain region, river flow shows severely less variability. We investigate what processes lead to this apparent discrepancy by using a simple but robust hydrological model that we thoroughly validate with remote sensing snow cover observations, Gravity Recovery and Climate Experiment (GRACE) data, highlighting changes in total water storage, and hydrograph comparison. We find that glaciers play a paramount role by buffering extreme meteorological conditions to sustain stream flow. In a simplified scheme, low precipitation amounts in winter result in small snow stocks, compensated for by more intensive glacier melt, and vice versa. By carrying out analyses over the extensive catchment area of the Amu Darya in the high mountain domain, we highlight regional differences in the effectiveness of this mechanism. Regional influences of wind systems and associated moisture transport as well as glaciated area emerge as ma