Hydrological and seasonal export mechanisms for nitrate transport from a forested catchment

International Nuclear Information System (INIS)

Rusjan, S; Mikos, M; Brilly, M

2008-01-01

Understanding of interactions between hydrological and biogeochemical responses of catchments on rainfall events is usually unclear from periodic measurements and requires tracing of the temporal dynamics of the processes. Smaller streams reflect strong connections between hydrological processes of the rainfall runoff formation and biogeochemical processes in the catchment; consequently, the responsiveness of the streamwater chemistry to changed hydrological states is very high. The study was carried out in 2007, within the 42 km 2 forested Padez catchment in the southwestern part of Slovenia, which is characterized by distinctive flushing, an almost torrential hydrological regime influenced by impermeable flysch geological settings. Recorded hydrographs which, in the hydrological and biogeochemical sense, differed substantially, disclosed a highly variable, but at the same time a strong linkage between hydrological, biogeochemical and particular topographic controls of nitrate exports from the spatial perspective of a studied catchment. The role of specific hydrological events on the nitrate mobilization proved to be important as the size of the accumulated nitrate pool available for mobilization was large throughout the observed hydrographs. The biogeochemical environment of the forest soils presumably significantly affects the size of the available nitrate pool in the studied catchment.

Behaviour of arsenic in forested catchments following a high-pollution period

International Nuclear Information System (INIS)

Novak, Martin; Erbanova, Lucie; Fottova, Daniela; Cudlin, Pavel; Kubena, Ales

2011-01-01

Due to high availability of adsorption sites, forested catchments could be net sinks for pollutant arsenic both during the period of increasing and decreasing pollution. We tested this hypothesis along a north-south pollution gradient in spruce die-back affected areas of Central Europe. For two water years (2007-2008), we monitored As fluxes via spruce-canopy throughfall, open-area precipitation, and runoff in four headwater catchments (Czech Republic). Since 1980, atmospheric As inputs decreased 26 times in the north, and 13 times in the south. Arsenic export by runoff was similar to atmospheric inputs at three sites, resulting in a near-zero As mass balance. One site exhibited a net export of As (2.2 g ha -1 yr -1 ). In contrast, the preceding period (1995-2006) showed much higher As fluxes, and higher As export. Czech catchments do not serve as net sinks of atmospheric As. A considerable proportion of old industrial arsenic is flushed out of the soil. - Following a period of high atmospheric As deposition, a considerable proportion of old industrial arsenic is flushed out of soil and exported from forested catchments.

Seasonal snow accumulation in the mid-latitude forested catchment

Czech Academy of Sciences Publication Activity Database

Šípek, Václav; Tesař, Miroslav

2014-01-01

Roč. 69, č. 11 (2014), s. 1562-1569 ISSN 0006-3088 R&D Projects: GA TA ČR TA02021451 Institutional support: RVO:67985874 Keywords : snow depth * snow water equivalent * forested catchment Subject RIV: DA - Hydrology ; Limnology Impact factor: 0.827, year: 2014

N fluxes in two nitrogen saturated forested catchments in Germany: dynamics and modelling with INCA

Directory of Open Access Journals (Sweden)

J.-J. Langusch

2002-01-01

Full Text Available The N cycle in forests of the temperate zone in Europe has been changed substantially by the impact of atmospheric N deposition. Here, the fluxes and concentrations of mineral N in throughfall, soil solution and runoff in two German catchments, receiving high N inputs are investigated to test the applicability of an Integrated Nitrogen Model for European Catchments (INCA to small forested catchments. The Lehstenbach catchment (419 ha is located in the German Fichtelgebirge (NO Bavaria, 690-871 m asl. and is stocked with Norway spruce (Picea abies (L. Karst. of different ages. The Steinkreuz catchment (55 ha with European beech (Fagus sylvatica L. as the dominant tree species is located in the Steigerwald (NW Bavaria, 400-460 m asl.. The mean annual N fluxes with throughfall were slightly higher at the Lehstenbach (24.6 kg N ha-1 than at the Steinkreuz (20.4 kg N ha-1. In both catchments the N fluxes in the soil are dominated by NO3. At Lehstenbach, the N output with seepage at 90 cm soil depth was similar to the N flux with throughfall. At Steinkreuz more than 50 % of the N deposited was retained in the upper soil horizons. In both catchments, the NO3 fluxes with runoff were lower than those with seepage. The average annual NO3 concentrations in runoff in both catchments were between 0.7 to 1.4 mg NO3-N L-1 and no temporal trend was observed. The N budgets at the catchment scale indicated similar amounts of N retention (Lehstenbach: 19 kg N ha-1yr-1 ; Steinkreuz: 17 kg N ha-1yr-1. The parameter settings of the INCA model were simplified to reduce the model complexity. In both catchments, the NO3 concentrations and fluxes in runoff were matched well by the model. The seasonal patterns with lower NO3 runoff concentrations in summer at the Lehstenbach catchment were replicated. INCA underestimated the increased N3 concentrations during short periods of rewetting in late autumn at the Steinkreuz catchment. The model will be a helpful tool for the

Peak Flow Responses and Recession Flow Characteristics After Thinning of Japanese Cypress Forest in a Headwater Catchment

Science.gov (United States)

We evaluated the effects of forest thinning on peak flow and recession characteristics of storm runoff in headwater catchments at Mie Prefecture, Japan. In catchment M5, 58.3% of stems were removed, whereas catchment M4 remained untreated as a control catchment. Storm precipitati...

Water and salt balance modelling to predict the effects of land-use changes in forested catchments. 1. Small catchment water balance model

Science.gov (United States)

Sivapalan, Murugesu; Ruprecht, John K.; Viney, Neil R.

1996-03-01

A long-term water balance model has been developed to predict the hydrological effects of land-use change (especially forest clearing) in small experimental catchments in the south-west of Western Australia. This small catchment model has been used as the building block for the development of a large catchment-scale model, and has also formed the basis for a coupled water and salt balance model, developed to predict the changes in stream salinity resulting from land-use and climate change. The application of the coupled salt and water balance model to predict stream salinities in two small experimental catchments, and the application of the large catchment-scale model to predict changes in water yield in a medium-sized catchment that is being mined for bauxite, are presented in Parts 2 and 3, respectively, of this series of papers.The small catchment model has been designed as a simple, robust, conceptually based model of the basic daily water balance fluxes in forested catchments. The responses of the catchment to rainfall and pan evaporation are conceptualized in terms of three interdependent subsurface stores A, B and F. Store A depicts a near-stream perched aquifer system; B represents a deeper, permanent groundwater system; and F is an intermediate, unsaturated infiltration store. The responses of these stores are characterized by a set of constitutive relations which involves a number of conceptual parameters. These parameters are estimated by calibration by comparing observed and predicted runoff. The model has performed very well in simulations carried out on Salmon and Wights, two small experimental catchments in the Collie River basin in south-west Western Australia. The results from the application of the model to these small catchments are presented in this paper.

Predicting forested catchment evapotranspiration and streamflow from stand sapwood area and Aridity Index

Science.gov (United States)

Lane, Patrick

2016-04-01

Estimating the water balance of ungauged catchments has been the subject of decades of research. An extension of the fundamental problem of estimating the hydrology is then understanding how do changes in catchment attributes affect the water balance component? This is a particular issue in forest hydrology where vegetation exerts such a strong influence on evapotranspiration (ET), and consequent streamflow (Q). Given the primacy of trees in the water balance, and the potential for change to species and density through logging, fire, pests and diseases and drought, methods that directly relate ET/Q to vegetation structure, species, and stand density are very powerful. Plot studies on tree water use routinely use sapwood area (SA) to calculate transpiration and upscale to the stand/catchment scale. Recent work in south eastern Australian forests have found stand-wide SA to be linearly correlated (R2 = 0.89) with long term mean annual loss (P-Q), and hence, long term mean annual catchment streamflow. Robust relationships can be built between basal area (BA), tree density and stand SA. BA and density are common forest inventory measurements. Until now, no research has related the fundamental stand attribute of SA to streamflow. The data sets include catchments that have been thinned and with varying age classes. Thus far these analyses have been for energy limited systems in wetter forest types. SA has proven to be a more robust biometric than leaf area index which varies seasonally. That long term ET/Q is correlated with vegetation conforms to the Budyko framework. Use of a downscaled (20 m) Aridity Index (AI) has shown distinct correlations with stand SA, and therefore T. Structural patterns at a the hillslope scale not only correlate with SA and T, but also with interception (I) and forest floor evaporation (Es). These correlations between AI and I and Es have given R2 > 0.8. The result of these studies suggest an ability to estimate mean annual ET fluxes at sub

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

Science.gov (United States)

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

Soil water storage, rainfall and runoff relationships in a tropical dry forest catchment

Science.gov (United States)

Farrick, Kegan K.; Branfireun, Brian A.

2014-12-01

In forested catchments, the exceedance of rainfall and antecedent water storage thresholds is often required for runoff generation, yet to our knowledge these threshold relationships remain undescribed in tropical dry forest catchments. We, therefore, identified the controls of streamflow activation and the timing and magnitude of runoff in a tropical dry forest catchment near the Pacific coast of central Mexico. During a 52 day transition phase from the dry to wet season, soil water movement was dominated by vertical flow which continued until a threshold soil moisture content of 26% was reached at 100 cm below the surface. This satisfied a 162 mm storage deficit and activated streamflow, likely through lateral subsurface flow pathways. High antecedent soil water conditions were maintained during the wet phase but had a weak influence on stormflow. We identified a threshold value of 289 mm of summed rainfall and antecedent soil water needed to generate >4 mm of stormflow per event. Above this threshold, stormflow response and magnitude was almost entirely governed by rainfall event characteristics and not antecedent soil moisture conditions. Our results show that over the course of the wet season in tropical dry forests the dominant controls on runoff generation changed from antecedent soil water and storage to the depth of rainfall.

Effects of harvest on carbon and nitrogen dynamics in a Pacific Northwest forest catchment

Science.gov (United States)

We used a new ecohydrological model, Visualizing Ecosystems for Land Management Assessments (VELMA), to analyze the effects of forest harvest on catchment carbon and nitrogen dynamics. We applied the model to a 10 ha headwater catchment in the western Oregon Cascade Range where t...

Forest fire impact on the hydrological response in small catchment of NW Spain

Directory of Open Access Journals (Sweden)

J. Canceio-González

2013-05-01

Full Text Available Hydrological studies were carried out in two catchments (burnt and unburned, to determine the processes related to the streamflow changes and the possible effects on the runoff coefficients produced by a forest fire in the summer of 2007, which affected 50% of the area of one of the catchments. Comparative analysis of the changes in the monthly streamflow values revealed that during the wettest months, the runoff was higher in the burnt catchment during the first two years, and was very similar in both catchments during the third year. Calculation of the annual runoff coefficient confirmed these findings and showed that the differences between the coefficients in the catchments were negligible in the final year. In both cases, this can be explained by regeneration of the vegetation after fire.

Acid deposition and water use efficiency in Appalachian forests

Science.gov (United States)

Malcomb, J.

2017-12-01

Multiple studies have reported increases in forest water use efficiency in recent decades, but the drivers of these trends remain uncertain. While acid deposition has profoundly altered the biogeochemistry of Appalachian forests in the past century, its impacts on forest water use efficiency have been largely overlooked. Plant ecophysiology literature suggests that plants up-regulate transpiration in response to soil nutrient limitation in order to maintain sufficient mass flow of nutrients. To test the impacts of acid deposition on forest eco-hydrology in central Appalachia, we integrated dendrochronological techniques, including tree ring δ13C analysis, with catchment water balance data from the Fernow Experimental Forest in West Virginia. Tree cores from four species were collected in Fernow Watershed 3, which has received experimental ammonium sulfate additions since 1989, and Watershed 7, an adjacent control catchment. Initial results suggest that acidification treatments have not significantly influenced tree productivity compared to a control watershed, but the effect varies by species, with tulip poplar showing greatest sensitivity to acidification. Climatic water balance, defined as the difference between growing season precipitation and evapotranspiration, is significantly related to annual tree ring growth, suggesting that climate may be driving tree growth trends in chronically acidified Appalachian forests. Tree ring 13C analysis from Fernow cores is underway and these data will be integrated with catchment hydrology data from five other sites in central Appalachia and the U.S. Northeast, representing a range of forest types, soil base saturations, and acid deposition histories. This work will advance understanding of how climate and acid deposition interact to influence forest productivity and water use efficiency, and improve our ability to model carbon and water cycling in forested ecosystems impacted by acid deposition.

Forests in catchment areas with special reference to the MUDA and Ahning dams: their roles in biodiversity conservation

International Nuclear Information System (INIS)

Mashhor Mansor

2002-01-01

During the field surveys conducted at the Muda and Ahning catchment areas, several rare and endemic plant species were recorded. The presence of relatively high population of Lagerstroemia speciosa in Muda is one of the conspicuous features of the forest in this catchment area. Unlike the Muda lake, a blue green algal bloom Oscillatoria kawamurde was observed at some parts of the Ahning lake particularly at the water surface. These catchment areas not only act as a buffer zone in the overall forest hydrological cycle but also play important roles in protecting and harbouring various species of plants and animals. (Author)

Modelling the impact of forest loss on shallow landslide sediment yield, Ijuez river catchment, Spanish Pyrenees

Directory of Open Access Journals (Sweden)

2007-01-01

Full Text Available The SHETRAN model for simulating the sediment yield arising from shallow landslides at the scale of a river catchment was applied to the 45-km2 Ijuez catchment in the central Spanish Pyrenees, to investigate the effect of loss of forest cover on landslide and debris flow incidence and on catchment sediment yield. The application demonstrated how such a model, with a large number of parameters to be evaluated, can be used even when directly measured data are not available: rainfall and discharge time series were generated by reference to other local records and data providing the basis for a soil map were obtained by a short field campaign. Uncertainty bounds for the outputs were determined as a function of the uncertainty in the values of key model parameters. For a four-year period and for the existing forested state of the catchment, a good ability to simulate the observed long term spatial distribution of debris flows (represented by a 45-year inventory and to determine catchment sediment yield within the range of regional observations was demonstrated. The lower uncertainty bound on simulated landslide occurrence approximated the observed annual rate of landsliding and suggests that landslides provide a relatively minor proportion of the total sediment yield, at least in drier years. A scenario simulation in which the forest cover was replaced by grassland indicated an increase in landsliding but a decrease in the number of landslides which evolve into debris flows and, at least for drier years, a reduction in sediment delivery to the channel network.

EVALUATION OF WATER RETENTION CAPABILITY IN WETLANDS AT SMALL FOREST CATCHMENT

Directory of Open Access Journals (Sweden)

Daniel Liberacki

2015-07-01

Full Text Available The paper presents the results of researches carried out in the middle part of Pizza Zielonka forest complex. The aim was the evaluation of retention changes at wetlands and mid-forest ponds. The object of the study was the catchment of the Trojanka watercourse, considering from the origin to the cross-section of Zielonka Lake. The catchment is located in in the central part of the Wielkopolska region, approximatelly 20 km on the North-East of Poznań. The area of this forestall catchment is about 223 ha. In the paper an analysis of the results from three hydrological years was presented. The results of the years 1987 (wet year, 2003 (dry year and 2009 (medium year were analysed against meteorological conditions. Retention capacity in each wetlands, as well as the possibility of water retention in the Trojanka watercourse was calculated. The researches confirmed significant meteorological conditions influence the amount of retentioned water. The calculated capacity of retentioned water was 15 852 m3 considering the total area of wetland and swamp (8,58 ha and precipitation sum of 555 mm. 18% increase of water capacity was observed in wet year (1987 In this year the sum of precipitation was 100 mm higher than multiyear average sum. Meanwhile 62% decrease of water capacity was observed in dry year (2003, when the precipitation sum was 208 mm lower than multiyear average one.

Nitrous oxide and methane exchange in two small temperate forest catchments - effects of hydrological gradients and implications for global warming potentials of forest soils

DEFF Research Database (Denmark)

Christiansen, Jesper Riis; Vesterdal, Lars; Gundersen, Per

2012-01-01

half the catchment area at both sites, the global warming potential (GWP) derived from N2O and CH4 was more than doubled when accounting for these wet areas in the catchments. The results stress the importance of wet soils in assessments of forest soil global warming potentials, as even small...

Impact of wildfire on stream nutrient chemistry and ecosystem metabolism in boreal forest catchments of interior Alaska

Science.gov (United States)

Emma F. Betts; Jeremy B. Jones

2009-01-01

With climatic warming, wildfire occurrence is increasing in the boreal forest of interior Alaska. Loss of catchment vegetation during fire can impact streams directly through altered solute and debris inputs and changed light and temperature regimes. Over longer time scales, fire can accelerate permafrost degradation, altering catchment hydrology and stream nutrient...

First use of a compound-specific stable isotope (CSSI) technique to trace sediment transport in upland forest catchments of Chile.

Science.gov (United States)

Bravo-Linares, Claudio; Schuller, Paulina; Castillo, Alejandra; Ovando-Fuentealba, Luis; Muñoz-Arcos, Enrique; Alarcón, Oscar; de Los Santos-Villalobos, Sergio; Cardoso, Renan; Muniz, Marcelo; Meigikos Dos Anjos, Roberto; Bustamante-Ortega, Ramón; Dercon, Gerd

2018-03-15

Land degradation is a problem affecting the sustainability of commercial forest plantations. The identification of critical areas prone to erosion can assist this activity to better target soil conservation efforts. Here we present the first use of the carbon-13 signatures of fatty acids (C14 to C24) in soil samples for spatial and temporal tracing of sediment transport in river bodies of upland commercial forest catchments in Chile. This compound-specific stable isotope (CSSI) technique was tested as a fingerprinting approach to determine the degree of soil erosion in pre-harvested forest catchments with surface areas ranging from 12 to 40ha. For soil apportionment a mixing model based on a Bayesian inference framework was used (CSSIAR v.2.0). Approximately four potential sediment sources were used for the calculations of all of the selected catchments. Unpaved forestry roads were shown to be the main source of sediment deposited at the outlet of the catchments (30-75%). Furthermore, sampling along the stream channel demonstrated that sediments were mainly comprised of sediment coming from the unpaved roads in the upper part of the catchments (74-98%). From this it was possible to identify the location and type of primary land use contributing to the sediment delivered at the outlet of the catchments. The derived information will allow management to focus efforts to control or mitigate soil erosion by improving the runoff features of the forest roads. The use of this CSSI technique has a high potential to help forestry managers and decision makers to evaluate and mitigate sources of soil erosion in upland forest catchments. It is important to highlight that this technique can also be a good complement to other soil erosion assessment and geological fingerprinting techniques, especially when attempting to quantify (sediment loads) and differentiate which type of land use most contributes to sediment accumulation. Copyright © 2017 Elsevier B.V. All rights reserved.

Element budgets of two contrasting catchments in the Black Forest (Federal Republic of Germany)

Science.gov (United States)

Feger, K. H.; Brahmer, G.; Zöttl, H. W.

1990-08-01

Rainfall and throughfall inputs of all major cations and anions, via open-field bulk precipitation and canopy throughfall, are compared with streamwater outputs in two forested catchments at higher altitudes of the Black Forest. The sites differ considerably in terms of bedrock geology, soil type, soilwater characteristics, topography, and forest management history. Deposition at both sites is almost equal and, in contrast to other forest areas in Central Europe, of a low-to-moderate level. Dry deposition does not seem to play an important role. Distinct differences in the elemental output emerge owing to the differing site conditions. At Villingen, deposited nitrogen is almost totally retained, whereas at Schluchsee, nitrogen output and input are of the same order of magnitude. This is consistent with the different nitrogen nutrition level of the stands, microbial turnover in the soil, and former management practices (change of tree species, excessive nutrient export). Sulphur is not retained in either of the catchments. At Schluchsee, sulphur export exceeds input from canopy throughfall by a factor of 2.5. The higher output rates, both of nitrogen and sulphur at Schluchsee, are due to the much higher microbial mineralization of organic matter as shown by previous incubation tests. Differences in cation and proton export are mainly caused by a different drainage pattern. In contrast to the Schluchsee catchment, where vertical water pathways prevail, the streamwater solute output at Villingen is dominated by a shallow subsurface runoff. Atmospheric deposition is a contributing, but not the dominant, factor in the biogeochemical cycling at these sites. Hence, a generally applicable quantitative definition of 'critical loads', especially for nitrogen, is illusory and the use of such numbers will be misleading.

Soil Erosion Analysis in a Small Forested Catchment Supported by ArcGIS Model Builder

Directory of Open Access Journals (Sweden)

CSÁFORDI, Péter

2012-01-01

Full Text Available To implement the analysis of soil erosion with the USLE in a GIS environment, a new workflow has been developed with the ArcGIS Model Builder. The aim of this four-part framework is to accelerate data processing and to ensure comparability of soil erosion risk maps. The first submodel generates the stream network with connected catchments, computes slope conditions and the LS factor in USLE based on the DEM. The second submodel integrates stream lines, roads, catchment boundaries, land cover, land use, and soil maps. This combined dataset is the basis for the preparation of other USLE-factors. The third submodel estimates soil loss, and creates zonal statistics of soil erosion. The fourth submodel classifies soil loss into categories enabling the comparison of modelled and observed soil erosion. The framework was applied in a small forested catchment in Hungary. Although there is significant deviation between the erosion of different land covers, the predicted specific soil loss does not increase above the tolerance limit in any area unit. The predicted surface soil erosion in forest subcompartments mostly depends on the slope conditions.

Effects of forest harvesting on summer stream temperatures in New Brunswick, Canada: an inter-catchment, multiple-year comparison

Directory of Open Access Journals (Sweden)

C. P.-A. Bourque

2001-01-01

Full Text Available This paper presents a pre- and post-harvest comparison of stream temperatures collected in five neighbouring streams (sub-catchments over a period of five years (1994-1998. The aim of the study was to determine whether land cover changes from clear cutting in areas outside forest buffer zones (applied to streams >0.5 m wide might contribute to an increase in summer mean stream temperatures in buffered streams downslope by infusion of warmed surface and sub-surface water into the streams. Specific relationships were observed in all five forest streams investigated. To assist in the analysis, several spatially-relevant variables, such as land cover change, mid-summer potential solar radiation, flow accumulation, stream location and slope of the land were determined, in part, from existing aerial photographs, GIS-archived forest inventory data and a digital terrain model of the study area. Spatial calculations of insolation levels for July 15th were used as an index of mid-summer solar heating across sub-catchments. Analysis indicated that prior to the 1995 harvest, differences in stream temperature could be attributed to (i topographic position and catchment-to-sun orientation, (ii the level of cutting that occurred in the upper catchment prior to the start of the study, and (iii the average slope within harvested areas. Compared to the pre-harvest mean stream temperatures in 1994, mean temperatures in the three streams downslope from the 1995 harvest areas increased by 0.3 to 0.7°C (representing a 4-8% increase; p-value of normalised temperatures Keywords: terrain attributes, solar radiation, land cover, forest buffers, New Brunswick regulations, spatial modelling, DEM, forest covertypes

Soil and water acidification of forest soils in the low-polluted area of Schoenbuch forest reservation

International Nuclear Information System (INIS)

Flegr, M.; Monn, L.

1990-01-01

At a comparatively low atmospheric pollution load of two wood-covered catchment areas the coniferous forest stand is characterized by increased material depositons and large element concentrations in the main root space. This leads to accumulation of acidifying agents and heavy metals in the seepage water. The heavy metals which pass into the recipients with the displaced soil solution determine most of the dispersion of dissolved heavy metals in the plateau landscape. On the other hand, the fraction of heavy metals bound to airborne particulates predominates in the valley landscape because of the stronger relief and the resulting sediment transport. In the shallow groundwaters, the sulfates and nitrate concentrations are much higher than in the deeper ground waters. (orig.) [de

Stable water isotopes suggest sub-canopy water recycling in a northern forested catchment

Science.gov (United States)

Mark B. Green; Bethany K. Laursen; John L. Campbell; Kevin J. McGuire; Eric P. Kelsey

2015-01-01

Stable water isotopes provide a means of tracing many hydrologic processes, including poorly understood dynamics like soil water interactions with the atmosphere. We present a four-year dataset of biweekly water isotope samples from eight fluxes and stores in a headwater catchment at the Hubbard Brook Experimental Forest, New Hampshire, USA. We use Dansgaard's...

Estimating Catchment-Scale Snowpack Variability in Complex Forested Terrain, Valles Caldera National Preserve, NM

Science.gov (United States)

Harpold, A. A.; Brooks, P. D.; Biederman, J. A.; Swetnam, T.

2011-12-01

Difficulty estimating snowpack variability across complex forested terrain currently hinders the prediction of water resources in the semi-arid Southwestern U.S. Catchment-scale estimates of snowpack variability are necessary for addressing ecological, hydrological, and water resources issues, but are often interpolated from a small number of point-scale observations. In this study, we used LiDAR-derived distributed datasets to investigate how elevation, aspect, topography, and vegetation interact to control catchment-scale snowpack variability. The study area is the Redondo massif in the Valles Caldera National Preserve, NM, a resurgent dome that varies from 2500 to 3430 m and drains from all aspects. Mean LiDAR-derived snow depths from four catchments (2.2 to 3.4 km^2) draining different aspects of the Redondo massif varied by 30%, despite similar mean elevations and mixed conifer forest cover. To better quantify this variability in snow depths we performed a multiple linear regression (MLR) at a 7.3 by 7.3 km study area (5 x 106 snow depth measurements) comprising the four catchments. The MLR showed that elevation explained 45% of the variability in snow depths across the study area, aspect explained 18% (dominated by N-S aspect), and vegetation 2% (canopy density and height). This linear relationship was not transferable to the catchment-scale however, where additional MLR analyses showed the influence of aspect and elevation differed between the catchments. The strong influence of North-South aspect in most catchments indicated that the solar radiation is an important control on snow depth variability. To explore the role of solar radiation, a model was used to generate winter solar forcing index (SFI) values based on the local and remote topography. The SFI was able to explain a large amount of snow depth variability in areas with similar elevation and aspect. Finally, the SFI was modified to include the effects of shading from vegetation (in and out of

Managing salinity in Upper Colorado River Basin streams: Selecting catchments for sediment control efforts using watershed characteristics and random forests models

Science.gov (United States)

Tillman, Fred; Anning, David W.; Heilman, Julian A.; Buto, Susan G.; Miller, Matthew P.

2018-01-01

Elevated concentrations of dissolved-solids (salinity) including calcium, sodium, sulfate, and chloride, among others, in the Colorado River cause substantial problems for its water users. Previous efforts to reduce dissolved solids in upper Colorado River basin (UCRB) streams often focused on reducing suspended-sediment transport to streams, but few studies have investigated the relationship between suspended sediment and salinity, or evaluated which watershed characteristics might be associated with this relationship. Are there catchment properties that may help in identifying areas where control of suspended sediment will also reduce salinity transport to streams? A random forests classification analysis was performed on topographic, climate, land cover, geology, rock chemistry, soil, and hydrologic information in 163 UCRB catchments. Two random forests models were developed in this study: one for exploring stream and catchment characteristics associated with stream sites where dissolved solids increase with increasing suspended-sediment concentration, and the other for predicting where these sites are located in unmonitored reaches. Results of variable importance from the exploratory random forests models indicate that no simple source, geochemical process, or transport mechanism can easily explain the relationship between dissolved solids and suspended sediment concentrations at UCRB monitoring sites. Among the most important watershed characteristics in both models were measures of soil hydraulic conductivity, soil erodibility, minimum catchment elevation, catchment area, and the silt component of soil in the catchment. Predictions at key locations in the basin were combined with observations from selected monitoring sites, and presented in map-form to give a complete understanding of where catchment sediment control practices would also benefit control of dissolved solids in streams.

Using 137Cs and 210Pbex and other sediment source fingerprints to document suspended sediment sources in small forested catchments in south-central Chile

International Nuclear Information System (INIS)

Schuller, P.; Walling, D.E.; Iroumé, A.; Quilodrán, C.; Castillo, A.; Navas, A.

2013-01-01

A study of the impact of forest harvesting operations on sediment mobilization from forested catchments has been undertaken in south-central Chile. The study focused on two sets of small paired catchments (treatment and control), with similar soil type, but contrasting mean annual rainfall, located about 400 km apart at Nacimiento (1200 mm yr −1 ) and Los Ulmos (2500 mm yr −1 ). The objective was to study the changes in the relative contribution of the primary sources of fine sediment caused by forestry operations. Attention focused on the pre-harvest and post-harvest periods and the post-replanting period was included for the Nacimiento treatment catchment. The sediment source fingerprinting technique was used to document the contributions of the potential sources. Emphasis was placed on discriminating between the forest slopes, forest roads and channel erosion as potential sources of fine sediment and on assessing the relative contributions of these three sources to the sediment yield from the catchments. The fallout radionuclides (FRNs) 137 Cs and excess lead-210, the environmental radionuclides 226 Ra and 40 K and soil organic matter (SOM) were tested as possible fingerprints for discriminating between potential sediment sources. The Kruskal–Wallis test and discriminant function analysis were used to guide the selection of the optimum fingerprint set for each catchment and observation period. Either one or both of the FRNs were selected for inclusion in the optimum fingerprint for all datasets. The relative contribution of each sediment source to the target sediment load was estimated using the selected fingerprint properties, and a mixing model coupled with a Monte Carlo simulation technique that takes account of uncertainty in characterizing sediment source properties. The goodness of fit of the mixing model was tested by comparing the measured and simulated fingerprint properties for the target sediment samples. In the Nacimiento treatment catchment

Modelling the fate of hydrophobic organic contaminants in a boreal forest catchment: A cross disciplinary approach to assessing diffuse pollution to surface waters

International Nuclear Information System (INIS)

Bergknut, Magnus; Meijer, Sandra; Halsall, Crispin; Agren, Anneli; Laudon, Hjalmar; Koehler, Stephan; Jones, Kevin C.; Tysklind, Mats; Wiberg, Karin

2010-01-01

The fate of hydrophobic organic compounds (HOCs) in soils and waters in a northern boreal catchment was explored through the development of a chemical fate model in a well-characterised catchment system dominated by two land types: forest and mire. Input was based solely on atmospheric deposition, dominated by accumulation in the winter snowpack. Release from soils was governed by the HOC concentration in soil, the soil organic carbon fraction and soil-water DOC content. The modelled export of selected HOCs in surface waters ranged between 11 and 250 ng day -1 during the snow covered period, compared to 200 and 9600 ng/d during snow-melt; highlighting the importance of the snow pack as a source of these chemicals. The predicted levels of HOCs in surface water were in reasonable agreement to a limited set of measured values, although the model tended to over predict concentrations of HOCs for the forested sub-catchment, by over an order of magnitude in the case of hexachlorobenzene and PCB 180. This possibly reflects both the heterogeneity of the forest soils and the complicated and changing hydrology experienced between the different seasons. - The fate of hydrophobic organic contaminants in a boreal forest catchment is connected to the flux of dissolved organic carbon and seasonal deposition.

Quantifying the variability of snowpack properties and processes in a small-forested catchment representative of the boreal zone

Science.gov (United States)

Parajuli, A.; Nadeau, D.; Anctil, F.; Parent, A. C.; Bouchard, B.; Jutras, S.

2017-12-01

In snow-fed catchments, it is crucial to monitor and to model snow water equivalent (SWE), particularly to simulate the melt water runoff. However, the distribution of SWE can be highly heterogeneous, particularly within forested environments, mainly because of the large variability in snow depths. Although the boreal forest is the dominant land cover in Canada and in a few other northern countries, very few studies have quantified the spatiotemporal variability of snow depths and snowpack dynamics within this biome. The objective of this paper is to fill this research gap, through a detailed monitoring of snowpack dynamics at nine locations within a 3.57 km2 experimental forested catchment in southern Quebec, Canada (47°N, 71°W). The catchment receives 6 m of snow annually on average and is predominantly covered with balsam fir stand with some traces of spruce and white birch. In this study, we used a network of nine so-called `snow profiling stations', providing automated snow depth and snowpack temperature profile measurements, as well as three contrasting sites (juvenile, sapling and open areas) where sublimation rates were directly measured with flux towers. In addition, a total of 1401 manual snow samples supported by 20 snow pits measurements were collected throughout the winter of 2017. This paper presents some preliminary analyses of this unique dataset. Simple empirical relations relying SWE with easy-to-determine proxies, such as snow depths and snow temperature, are tested. Then, binary regression trees and multiple regression analysis are used to model SWE using topographic characteristics (slope, aspect, elevation), forest features (tree height, tree diameter, forest density and gap fraction) and meteorological forcing (solar radiation, wind speed, snow-pack temperature profile, air temperature, humidity). An analysis of sublimation rates comparing open area, saplings and juvenile forest is also presented in this paper.

Land use planning for forest catchment of Arasbaran

International Nuclear Information System (INIS)

Dehdar Dargahi, M.; Makhdoum, M.F.

2001-01-01

In this study, land use planning for six hydrological units (296690 ha) of Arasbaran forest catchment (N W of Iran in Azerbaijan) has been conducted. The main objectives of the plan were to promote sustainable use, to increase living conditions, and enhance environmental conservation in the region. First, ecological and socio-economic resources were surveyed and mapped (scale 1:50000). Then data analysis and integration with system analysis approach were performed. As a result, 3556 micro-ecosystems were mapped. Ecological capability of mapping unit (MU) was evaluated for: agriculture, range management, forestry, eco tourism and conservation with the aid of specified ecological models. Finally with coordination of socioeconomic data and ecological capability of MU, priority of land uses with qualitative-analogous method was established. At the end, map of land use planning for six hydrological units was depicted for management purposes. The results show that %5.38 of allocated land use is suitable for irrigation farming, %1.32 for dry farming, %17.43 for range management, %15.17 for protected forestry, %2.13 for forest plantation, %28.47 for extensive eco tourism, %0.01 for intensive eco tourism and finally %30.09 for conservation

Long-term modelling of nitrogen turnover and critical loads in a forested catchment using the INCA model

Directory of Open Access Journals (Sweden)

J.-J. Langusch

2002-01-01

Full Text Available Many forest ecosystems in Central Europe have reached the status of N saturation due to chronically high N deposition. In consequence, the NO3 leaching into ground- and surface waters is often substantial. Critical loads have been defined to abate the negative consequences of the NO3 leaching such as soil acidification and nutrient losses. The steady state mass balance method is normally used to calculate critical loads for N deposition in forest ecosystems. However, the steady state mass balance approach is limited because it does not take into account hydrology and the time until the steady state is reached. The aim of this study was to test the suitability of another approach: the dynamic model INCA (Integrated Nitrogen Model for European Catchments. Long-term effects of changing N deposition and critical loads for N were simulated using INCA for the Lehstenbach spruce catchment (Fichtelgebirge, NE Bavaria, Germany under different hydrological conditions. Long-term scenarios of either increasing or decreasing N deposition indicated that, in this catchment, the response of nitrate concentrations in runoff to changing N deposition is buffered by a large groundwater reservoir. The critical load simulated by the INCA model with respect to a nitrate concentration of 0.4 mg N l–1 as threshold value in runoff was 9.7 kg N ha–1yr–1 compared to 10 kg ha–1yr–1 for the steady state model. Under conditions of lower precipitation (520 mm the resulting critical load was 7.7 kg N ha–1yr–1 , suggesting the necessity to account for different hydrological conditions when calculating critical loads. The INCA model seems to be suitable to calculate critical loads for N in forested catchments under varying hydrological conditions e.g. as a consequence of climate change. Keywords: forest ecosystem, N saturation, critical load, modelling, long-term scenario, nitrate leaching, critical loads reduction, INCA

Operational validation of a multi-period and multi-criteria model conditioning approach for the prediction of rainfall-runoff processes in small forest catchments

Science.gov (United States)

Choi, H.; Kim, S.

2012-12-01

Most of hydrologic models have generally been used to describe and represent the spatio-temporal variability of hydrological processes in the watershed scale. Though it is an obvious fact that hydrological responses have the time varying nature, optimal values of model parameters were normally considered as time invariants or constants in most cases. The recent paper of Choi and Beven (2007) presents a multi-period and multi-criteria model conditioning approach. The approach is based on the equifinality thesis within the Generalised Likelihood Uncertainty Estimation (GLUE) framework. In their application, the behavioural TOPMODEL parameter sets are determined by several performance measures for global (annual) and short (30-days) periods, clustered using a Fuzzy C-means algorithm, into 15 types representing different hydrological conditions. Their study shows a good performance on the calibration of a rainfall-runoff model in a forest catchment, and also gives strong indications that it is uncommon to find model realizations that were behavioural over all multi-periods and all performance measures, and multi-period model conditioning approach may become new effective tool for predictions of hydrological processes in ungauged catchments. This study is a follow-up study on the Choi and Beven's (2007) model conditioning approach to test how the approach is effective for the prediction of rainfall-runoff responses in ungauged catchments. To achieve this purpose, 6 small forest catchments are selected among the several hydrological experimental catchments operated by Korea Forest Research Institute. In each catchment, long-term hydrological time series data varying from 10 to 30 years were available. The areas of the selected catchments range from 13.6 to 37.8 ha, and all areas are covered by coniferous or broad-leaves forests. The selected catchments locate in the southern coastal area to the northern part of South Korea. The bed rocks are Granite gneiss, Granite or

Stream discharge of metals and rare earth elements in rainfall events in a forested catchment

International Nuclear Information System (INIS)

Matsunaga, Takeshi; Tsuduki, Katsunori; Yanase, Nobuyuki; Hanzawa, Yukiko; Naganawa, Hirochika; Inoue, Takanobu; Yamada, Toshiro; Miyata, Akifumi

2007-01-01

In a forested catchment rainfall event, the accelerated stream discharge of dissolved Cr, Cu, and Sb was attributed mainly to the first flush from the ground surface and/or instantaneous resuspension of stream sediment, while REE discharge was linked to that of dissolved organic matter from the soil layer. (author)

A Dataset for Three-Dimensional Distribution of 39 Elements Including Plant Nutrients and Other Metals and Metalloids in the Soils of a Forested Headwater Catchment.

Science.gov (United States)

Wu, B; Wiekenkamp, I; Sun, Y; Fisher, A S; Clough, R; Gottselig, N; Bogena, H; Pütz, T; Brüggemann, N; Vereecken, H; Bol, R

2017-11-01

Quantification and evaluation of elemental distribution in forested ecosystems are key requirements to understand element fluxes and their relationship with hydrological and biogeochemical processes in the system. However, datasets supporting such a study on the catchment scale are still limited. Here we provide a dataset comprising spatially highly resolved distributions of 39 elements in soil profiles of a small forested headwater catchment in western Germany () to gain a holistic picture of the state and fluxes of elements in the catchment. The elements include both plant nutrients and other metals and metalloids that were predominately derived from lithospheric or anthropogenic inputs, thereby allowing us to not only capture the nutrient status of the catchment but to also estimate the functional development of the ecosystem. Soil samples were collected at high lateral resolution (≤60 m), and element concentrations were determined vertically for four soil horizons (L/Of, Oh, A, B). From this, a three-dimensional view of the distribution of these elements could be established with high spatial resolution on the catchment scale in a temperate natural forested ecosystem. The dataset can be combined with other datasets and studies of the TERENO (Terrestrial Environmental Observatories) Data Discovery Portal () to reveal elemental fluxes, establish relations between elements and other soil properties, and/or as input for modeling elemental cycling in temperate forested ecosystems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The role of forest in runoff generation in a suburban catchment

Science.gov (United States)

Ferreira, C. S. S.; Soares, D.; Soares, A. J. D.; Coelho, C. O. A.; Steenhuis, T. S.; Keizer, J. J.; Walsh, R. P. D.

2012-04-01

Forests play an important role in the water cycle, particularly through their influence on infiltration and evapotranspiration processes. Removing forest for urban growth will affect the hydrological cycle, but to what degree is not known. To improve the knowledge about the role of forest areas in the catchment surface runoff, a total of nine runoff plots (16m2) was installed in the three predominant woodland types found in the small Ribeira dos Covões catchment (620ha), located in a rapid urbanizing area in central Portugal. The three representative study sites comprised: (i) a dense eucalyptus stand on a sandy-loam soil overlying sandstone; (ii) a open eucalyptus stand dominated by dense shrub vegetation, also on a sandy-loam soil overlying sandstone; (iii) a Mediterranean oak stand on a loamy soil overlying limestone. The three plots at each site were bounded by metal sheets and their outlets were connected to a modified Gerlach through for sediments retention and, subsequently, a tipping-bucket device and a tank for recording and collecting the runoff. The overland flow generated by the plots was monitored for almost one year. In addition, soil moisture content was measured automatically at 0-2, 5-10 and 15-20cm soil depth using 5 sensors per plot. Furthermore, soil water repellency was repeatedly measured on the field, through ethanol percentage method. In the dense eucalyptus forest the soil is hydrophobic during most of the year, just vanished after severe rainfall events. This reflects on low soil moisture content that reached 37% during wet periods. In this area, with an average slope of 20°±5°, the runoff coefficient ranged between 0.0% (for a 3mm rainfall event) and 2.2% (for a 23mm rainfall during hydrophobic conditions). In general, the runoff was higher when the soil was extremely repellent, but it also increased with soil moisture rise when the repellence was absent (reaching 0.6%). In the open eucalyptus forest, hydrophobicity is also presented

Nitrogen Deposition and Leaching from Two Forested Catchments in Southwest China — Preliminary Data and Research Needs

Directory of Open Access Journals (Sweden)

T. Larssen

2001-01-01

Full Text Available Increased nitrogen deposition has resulted in increased nitrogen pools and nitrogen leaching in European and North American forest soils. The development in Asia in general, and China in particular, suggests increased deposition of reduced nitrogen from changes in agricultural practices and of oxidized nitrogen from rapid growth of the transportation sector. Decreased nitrogen retention in forested areas in the future may cause increased NO3– leaching and, thus, acidification and eutrophication in surface waters. The differences in climate, ecosystems, land use, and deposition history make direct application of knowledge from studies in Europe and North America difficult. In Southwest China the potential for nitrogen mobilization from forest soils may be high because of the warm and humid climate, resulting in high decomposition rates of soil organic matter. However, there are very few data available for quantifying the suspected potential for increased nitrogen leaching in forest ecosystems. Here we present data from two forested catchments, dominated by Masson pine (Pinus massoniana, near Guiyang and Chongqing, respectively, in Southwest China. The present nitrogen deposition is moderate, estimated in the range from 10 to 40 kg N ha–1 year–1. The C/N ratios of the soils are generally below 15. Nitrate concentrations in soil water are rather variable in space, with highest values of several hundred microequivalents per liter. The turnover rate of nitrogen in the forest ecosystem is quite high compared to the atmospheric deposition rate. At present, nitrate runoff from the catchments is low and intermediate in Guiyang and Chongqing, respectively. More research is needed to improve our ability to predict future nitrogen leaching from subtropical Asian coniferous forests.

Ecological studies in the Ratanica catchment (Carpathian foothills, southern Poland) - an overview

International Nuclear Information System (INIS)

Grodzinska, K.; Szarek, G.

1995-01-01

This paper includes an overview of ecological studies conducted since 1986 in the Ratanica pine-beech forested catchment located in the polluted, high populated southern part of Poland. General characteristics of the catchment (including soil and vegetation, air pollution, input/output of nutrients and pollutants, element budget data and forest health assessment) are presented. Based on biogeochemical and bioindication results, the Ratanica catchment has been classified as a moderately to heavily deteriorated area. Predictions for this forested catchment for various deposition of anthropogenic pollutants, are also discussed. 22 refs., 1 fig

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.

Forest fuel and sulphur

International Nuclear Information System (INIS)

Lundborg, A.

1994-10-01

This report illustrates the sulphur cycle in forest fuel and in the forest ecosystem. The hypothesis is that sulphur dioxide from combustion of forest fuel is not more acidifying than sulphur that is mineralized from tree biomass if it is left in the forest instead of being burnt. The report gives an overview of the sulphur cycle in general together with the acidifying effect of sulphur. The sulphur content in wood biomass is about 1 mg/g in the needles and 0.2-0.3 mg/g in wood. Chipped forest fuel contains 0.2-0.5 mg S/g. A removal of 40 tonnes of felling residues per hectare may contain about 8-30 kg S. The sulphur occurs both in organic, often reduced, form and as sulphate. In situations of high availability to sulphur there will be an increased proportion of sulphate. After combustion some, perhaps half, of the sulphur is left in the ashes, most of which appears to be sulphate. In mineralisation of reduced organic sulphur, of type R-SH, the sulphur is released in the form of sulphide. Hydrogen sulphide, H2S, can be oxidised by microbes to sulphate, which should be acidifying (2 H+ will remain). A very rough estimate suggests that emissions of sulphur dioxide from forest fuel, spread over the period the trees are growing, and on the area from which the trees are taken, corresponds to 0.5% of the sulphur deposition in southern Sweden. Sulphur emissions from biofuel combustion are much lower than Sweden's and the EU's most stringent emission limits for coal. Whole-tree removal with return of ashes will theoretically give a considerable reduction in soil acidity since large quantities of nitrogen are removed and thus the acidifying effect of nitrogen will not occur. This should be of greater importance for forest acidification than the effect of biomass sulphur. 80 refs, numerous tabs

Ecosystem monitoring of radiocesium redistribution dynamics in a forested catchment in Fukushima after the nuclear power station accident in March 2011

Science.gov (United States)

Ohte, N.; Endo, I.; Ohashi, M.; Murakami, M.; Oda, T.; Hotta, N.; Yamanishi, R.; Sugiyama, Y.; Tanoi, K.; Kobayashi, N. I.; Ishii, N.

2016-12-01

The accident at the Fukushima Daiichi Nuclear Power Station (F1NPS) in March 2011 emitted 1.2 × 1016 Bq of cesium-137 (137Cs) into the surrounding environment. Radioactive substances, including 137Cs, were deposited onto forested areas in the northeastern region of Japan. To clarify the mechanisms of dispersion and export of 137Cs, within and from a forest ecosystem, we have conducted intensive field observations on hydrological processes and the 137Cs movement and storage in a forested headwater catchment in an area 50 km from F1NNS. Two major pathways of 137Cs transport were focused: 1) through the hydrological processes with dissolved and particulate or colloidal forms, and 2) by dispersion through the food web in the forest-stream ecological continuum. The 137Cs concentrations of stream waters were monitored. Various aquatic and terrestrial organisms were periodically sampled to measure their 137Cs concentrations. The results indicate that the major form of exported 137Cs is via suspended solid in the streamflow. Thus, high flows generated by a storm event accelerated strongly the transportation of 137Cs from the forested catchments. Estimation of 137Cs export from the forested catchments requires precise evaluation of the high water flow during storm events. On the other hand, dissolved form, especially mineral ion form of 137Cs were dominant in througfall and stemflow. Because the biggest pool of 137Cs in the forested ecosystem was the accumulated litters and detritus on the forest floor, 137Cs dispersion through food web was quicker through the detritus food chain than through the grazing food chain. 137Cs concentration of leaves (1.1k Bq/kg), barks (4.4-22.5 kBq/kg) woods (0.1-0.6 kBq/kg) and litters (1.3 kBq/kg) of a dominant deciduous tree (Quercus serrata) suggested that internal cyccling of 137Cs have aready occurred between surface soils including litter layer and plants.

Modelling long-term hydrochemical responce at ENCORE catchments in the UK and Norway

Energy Technology Data Exchange (ETDEWEB)

Jenkins, A; Wright, R F; Cosby, B J

1994-11-01

ENCORE is an interdisciplinary project focusing on biological and chemical response to environmental change and the links between terrestrial and aquatic ecosystems. This report applies the MAGIC model, which is a catchment-scale model of soil and water acidification, to ten ENCORE catchments in the UK and Norway and uses it to examine the dynamic response to several scenarios of future land-use. MAGIC is an acronym for Model for Acidification of Groundwater In Catchments. The model is evaluated against catchment manipulation studies involving acid addition, acid exclusion, terrestrial liming and upland afforestation. Critical loads for sulphur are calculated. At all sites MAGIC successfully simulates present-day observed stream and soil chemistry. The predicted response of soils and surface waters to the two standard future deposition scenarios is similar at all catchments. All catchments continue to acidify under the worst-case scenario and all catchments recover under the best-case scenario. Exceptions are related to situations with concurrent land-use change, or in the case of nitrogen saturation. The success of MAGIC illustrates its robustness and indicates that the major processes included in the model are correctly identified as the major mechanisms controlling catchment chemical response to acid input. 39 refs., 10 figs., 4 tabs.

Radioactive Cs-137 discharge from Headwater Forested Catchment in Fukushima after Fukushima Dai-ichi Nuclear Power Plant Accident

Science.gov (United States)

Iwagami, S.; Onda, Y.; Tsujimura, M.; Sakakibara, K.; Konuma, R.

2015-12-01

Radiocesium migration from headwater forested catchment is important perception as output from the forest which is also input to the subsequent various land use and downstream rivers after Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. In this study, Cs-137 concentration of dissolved water, suspended sediment and coarse organic matter such as leaf and branch were monitored. Discharge amount of stream water, suspended sediment and coarse organic matter were measured to investigate the discharge amount of radiocesium and composition of radiocesium discharge form through the headwater stream. Observation were conducted at stream site in four headwater catchments in Yamakiya district, located ~35 km north west of FDNPP from June 2011 (suspended sediment and coarse organic matter: August 2012) to December 2014.The Cs-137 concentration of dissolved water was around 1Bq/l at June 2011. Then declined to 0.1 Bq/l at December 2011. And in December 2014, it declined to 0.01 Bq/l order. Declining trend of Cs-137 concentration in dissolved water was expressed in double exponential model. Also temporary increase was observed in dissolved Cs-137 during the rainfall event. The Cs-137 concentration of suspended sediment and coarse organic matter were 170-49000 Bq/kg and 350-14000 Bq/kg respectably. The Cs-137 concentration of suspended sediment showed good correlation with average deposition density of catchment. The effect of decontamination works appeared in declining of Cs-137 concentration in suspended sediment. Contribution rate of Cs-137 discharge by suspended sediment was 96-99% during a year. Total annual Cs-137 discharge from the catchment were 0.02-0.3% of the deposition.

Analysing the Effects of Forest Cover and Irrigation Farm Dams on Streamflows of Water-Scarce Catchments in South Australia through the SWAT Model

Directory of Open Access Journals (Sweden)

Hong Hanh Nguyen

2017-01-01

Full Text Available To assist water resource managers with future land use planning efforts, the eco-hydrological model Soil and Water Assessment Tool (SWAT was applied to three catchments in South Australia that experience extreme low flow conditions. Particular land uses and management issues of interest included forest covers, known to affect water yields, and farm dams, known to intercept and change the hydrological dynamics in a catchment. The study achieved a satisfactory daily calibration when irrigation farm dams were incorporated in the model. For the catchment dominated by extreme low flows, a better daily simulation across a range of qualitative and quantitative metrics was gained using the base-flow static threshold optimization technique. Scenario analysis on effects of forest cover indicated an increase of surface flow and a reduction of base-flow when native eucalyptus lands were replaced by pastures and vice versa. A decreasing trend was observed for the overall water yield of catchments with more forest plantation due to the higher evapotranspiration (ET rate and the decline in surface flow. With regards to effects of irrigation farm dams, assessment on a daily time step suggested that a significant volume of water is stored in these systems with the water loss rate highest in June and July. On an annual basis, the model indicated that approximately 13.1% to 22.0% of water has been captured by farm dams for irrigation. However, the scenario analysis revealed that the purposes of use of farm dams rather than their volumetric capacities in the catchment determined the magnitude of effects on streamflows. Water extracted from farm dams for irrigation of orchards and vineyards are more likely to diminish streamflows than other land uses. Outputs from this study suggest that the water use restrictions from farm dams during recent drought periods were an effective tool to minimize impacts on streamflows.

Thinner eggshells of dipper (Cinclus cinclus) eggs from an acidified area compared to a non-acidified area in Norway

Energy Technology Data Exchange (ETDEWEB)

Nyboe, S.; Staurnes, M.; Jerstad, K. [Norwegian University of Science and Technology, Dragvoll (Norway). Dept. of Zoology

1997-01-01

Eggs of dippers Cinclus cinclus from a chronically acidified area in Southern Norway were compared with eggs from a non-acidified area in Central Norway. There were no differences in egg size, as measured by volume, weight, length and calculated surface area, between the two areas. Eggshells were 7.0% lighter and 6.1% thinner, as measured by the Ratcliffe index and 7.0% as measured by the eggshell index (shell weight/surface area) in Southern Norway than in Central Norway. The Ratcliffe and eggshell indices were highly correlated. Scanning electron micrography showed that the palisade layer of eggshells of eggs from the acidified area was 10.7% thinner than that of eggshells of eggs from the non-acidified area. Eggshell vapour permeability was not significantly influenced by area. Since the moderately lower thickness in Southern Norway was not accompanied by higher vapour permeability, this indicates that the reduced eggshell thickness did not cause desiccation of dipper eggs in the acidified area. The possibility of underestimating the environmental effects of acidification on dippers is discussed. 42 refs.,2 figs., 4 tabs.

Catchment conceptualisation for examining applicability of chloride mass balance method in an area with historical forest clearance

Directory of Open Access Journals (Sweden)

H. Guan

2010-07-01

Full Text Available Of the various approaches for estimating groundwater recharge, the chloride mass balance (CMB method is one of the most frequently used, especially for arid and semiarid regions. Widespread native vegetation clearance, common in many areas globally, has changed the land surface boundary condition, posing the question as to whether the current system has reached new chloride equilibrium, required for a CMB application. Although a one-dimensional CMB can be applied at a point where the water and chloride fluxes are locally in steady state, the CMB method is usually applied at a catchment scale owing to significant lateral flows in mountains. The applicability of the CMB method to several conceptual catchment types of various chloride equilibrium conditions is examined. The conceptualisation, combined with some local climate conditions, is shown to be useful in assessing whether or not a catchment has reached new chloride equilibrium. The six conceptual catchment types are tested with eleven selected catchments in the Mount Lofty Ranges (MLR, a coastal hilly area in South Australia having experienced widespread historical forest clearance. The results show that six of the eleven catchments match a type VI chloride balance condition (chloride non-equilibrium with a gaining stream, with the ratios of stream chloride output (O over atmospheric chloride input (I, or catchment chloride O/I ratios, ranging from 2 to 4. Two catchments match a type V chloride balance condition (chloride non-equilibrium with a losing stream, with catchment chloride O/I ratios about 0.5. For these type V and type VI catchments, the CMB method is not applicable. The results also suggest that neither a chloride O/I ratio less than one nor a low seasonal fluctuation of streamflow chloride concentration (a factor below 4 guarantees a chloride equilibrium condition in the study area. A large chloride O/I value (above one and a large fluctuation of streamflow chloride

Landscape Controls of CH4 Fluxes in a Catchment of the Forest Tundra in Northern Siberia

Science.gov (United States)

Flessa, H.; Rodionov, A.; Guggenberger, G.; Fuchs, H.; Magdon, P.; Shibistova, O.; Zrazhevskaya, G.; Kasansky, O.; Blodau, C.

2007-12-01

Soils have the capacity to both produce and consume atmospheric methane. The direction and the size of net- CH4 exchange between soils and atmosphere is mainly controlled by the soil aeration, temperature and the amount of bioavailable organic matter. All these factors are strongly influenced by distribution and seasonal dynamics of permafrost. Thus, distribution of permafrost and the thickness of the active layer can exert strong influence on CH4 dynamics in artic and northern boreal ecosystems. We analyzed the spatial and temporal variability of net-CH4 exchange within a catchment located in the Siberian forest tundra at the eastern shore of the lower Yenissej River to constrain the current function of this region as a sink or source of atmospheric CH4 and to gain insight into the potential for climatic change to alter the rate and form of carbon cycling and CH4 fluxes in this region. Net-fluxes of CH4 were measured from July to November 2003 and from August 2006 to July 2007 on representative soils of the catchment (mineral soils with different thawing depth, soils of bog plateaux) and on a thermokarst pond. In addition, dissolved CH4 in the stream draining the catchment was determined. Field observations, classification of landscape structures from satellite images and flux measurements were combined to estimate total catchment CH4 exchange. Nearly all soils of the catchment were net-sinks of atmospheric CH4 with annual CH4-C uptake rates ranging between 1.2 and 0.2 kg ha-1 yr-1. The active layer depth was the main factor determining the size of CH4 uptake. Total net-exchange of CH4 from the catchment was dominated by ponds that covered only about 2% of the catchment area. Due to high CH4 emission from these aquatic systems, the catchment was a net source of atmospheric CH4 with a mean annual emission of approximately 170 kg CH4-C ha-1. CH4 concentration in streams draining the catchment can help to identify areas with high CH4 production. The results suggest

Simulating Catchment Scale Afforestation for Mitigating Flooding

Science.gov (United States)

Barnes, M. S.; Bathurst, J. C.; Quinn, P. F.; Birkinshaw, S.

2016-12-01

After the 2013-14, and the more recent 2015-16, winter floods in the UK there were calls to 'forest the uplands' as a solution to reducing flood risk across the nation. However, the role of forests as a natural flood management practice remains highly controversial, due to a distinct lack of robust evidence into its effectiveness in reducing flood risk during extreme events. This project aims to improve the understanding of the impacts of upland afforestation on flood risk at the sub-catchment and full catchment scales. This will be achieved through an integrated fieldwork and modelling approach, with the use of a series of process based hydrological models to scale up and examine the effects forestry can have on flooding. Furthermore, there is a need to analyse the extent to which land management practices, catchment system engineering and the installation of runoff attenuation features (RAFs), such as engineered log jams, in headwater catchments can attenuate flood-wave movement, and potentially reduce downstream flood risk. Additionally, the proportion of a catchment or riparian reach that would need to be forested in order to achieve a significant impact on reducing downstream flooding will be defined. The consequential impacts of a corresponding reduction in agriculturally productive farmland and the potential decline of water resource availability will also be considered in order to safeguard the UK's food security and satisfy the global demand on water resources.

Fluvial sediment inputs to upland gravel bed rivers draining forested catchments: potential ecological impacts

Directory of Open Access Journals (Sweden)

S. D. Marks

1997-01-01

Full Text Available As identified by the detailed long-term monitoring networks at Plynlimon, increased sediment supply to upland fluvial systems is often associated with forestry land-use and practice. Literature is reviewed, in the light of recent results from Plynlimon sediment studies, to enable identification of the potential ecological impacts of fluvial particulate inputs to upland gravel bed rivers draining forested catchments similar to the headwaters of the River Severn. Both sediment transport and deposition can have significant impacts upon aquatic vertebrates, invertebrates and plants.

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.

Long-term monitored catchments in Norway - a hydrologic and chemical evaluation -

Energy Technology Data Exchange (ETDEWEB)

Lydersen, E

1994-10-20

About 20 years ago, long-term monitoring of small Norwegian catchments were initiated, because of increasing concern regarding acidification of surface water and damage to fish populations. Long range transported air pollutants were considered to be the major acidification factor and so both precipitation and runoff chemistry were included in the monitoring programme. This report contains a thorough hydrologic and chemical evaluation of precipitation and runoff water separately as well as relationships between precipitation chemistry and runoff chemistry. The data comes from four catchments: Birkenes, Storgama, Langtjern and Kaarvatn. The chapters are (1) Sampling and analysis, (2) Description of the catchments, (3) Hydrology, (4) Chemistry, with subsections on wet deposition, dry deposition, concentration of marine compounds with distance from the sea, acid precipitation, runoff chemistry, sulphuric acid and other acidifying compounds, acid neutralizing capacity, and aluminium, (5) Time trends in precipitation and runoff chemistry. The time trends are evaluated in relation to the declining emissions of sulphur compounds in Europe since the late seventies. 134 refs., 213 figs., 54 tabs.

Evaluating hillslope and riparian contributions to dissolved nitrogen (N) export from a boreal forest catchment

Science.gov (United States)

Blackburn, M.; Ledesma, José L. J.; Näsholm, Torgny; Laudon, Hjalmar; Sponseller, Ryan A.

2017-02-01

Catchment science has long held that the chemistry of small streams reflects the landscapes they drain. However, understanding the contribution of different landscape units to stream chemistry remains a challenge which frequently limits our understanding of export dynamics. For limiting nutrients such as nitrogen (N), an implicit assumption is that the most spatially extensive landscape units (e.g., uplands) act as the primary sources to surface waters, while near-stream zones function more often as sinks. These assumptions, based largely on studies in high-gradient systems or in regions with elevated inputs of anthropogenic N, may not apply to low-gradient, nutrient-poor, and peat-rich catchments characteristic of many northern ecosystems. We quantified patterns of N mobilization along a hillslope transect in a northern boreal catchment to assess the extent to which organic matter-rich riparian soils regulate the flux of N to streams. Contrary to the prevailing view of riparian functioning, we found that near-stream, organic soils supported concentrations and fluxes of ammonium (NH4+) and dissolved organic nitrogen that were much higher than the contributing upslope forest soils. These results suggest that stream N chemistry is connected to N mobilization and mineralization within the riparian zone rather than the wider landscape. Results further suggest that water table fluctuation in near-surface riparian soils may promote elevated rates of net N mineralization in these landscapes.

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

Streamflow response of a small forested catchment on different timescales

Directory of Open Access Journals (Sweden)

A. Zabaleta

2013-01-01

Full Text Available The hydrological response of a catchment to rainfall on different timescales is result of a complex system involving a range of physical processes which may operate simultaneously and have different spatial and temporal influences. This paper presents the analysis of streamflow response of a small humid-temperate catchment (Aixola, 4.8 km² in the Basque Country on different timescales and discusses the role of the controlling factors. Firstly, daily time series analysis was used to establish a hypothesis on the general functioning of the catchment through the relationship between precipitation and discharge on an annual and multiannual scale (2003–2008. Second, rainfall-runoff relationships and relationships among several hydrological variables, including catchment antecedent conditions, were explored at the event scale (222 events to check and improve the hypothesis. Finally, the evolution of electrical conductivity (EC during some of the monitored storm events (28 events was examined to identify the time origin of waters. Quick response of the catchment to almost all the rainfall events as well as a considerable regulation capacity was deduced from the correlation and spectral analyses. These results agree with runoff event scale data analysis; however, the event analysis revealed the non-linearity of the system, as antecedent conditions play a significant role in this catchment. Further, analysis at the event scale made possible to clarify factors controlling (precipitation, precipitation intensity and initial discharge the different aspects of the runoff response (runoff coefficient and discharge increase for this catchment. Finally, the evolution of EC of the waters enabled the time origin (event or pre-event waters of the quickflow to be established; specifically, the conductivity showed that pre-event waters usually represent a high percentage of the total discharge during runoff peaks. The importance of soil waters in the

Effect of tree thinning and skidding trails on hydrological connectivity in two Japanese forest catchments

Science.gov (United States)

López-Vicente, Manuel; Sun, Xinchao; Onda, Yuichi; Kato, Hiroaki; Gomi, Takashi; Hiraoka, Marino

2017-09-01

Land use composition and patterns influence the hydrological response in mountainous and forest catchments. In plantation forest, management operations (FMO) modify the spatial and temporal dynamics of overland flow processes. However, we found a gap in the literature focussed on modelling hydrological connectivity (HC) in plantation forest under different FMO. In this study, we simulated HC in two steep paired forest subcatchments (K2 and K3, 33.2 ha), composed of Japanese cypress (Chamaecyparis obtusa Endl.) and Japanese cedar (Cryptomeria japonica D. Don) plantations (59% of the total area) against a tree thinning intensity of 50% at different time. Additionally, construction of new skidding trails and vegetation recovery was simulated on five thinning-based scenarios that covered a 40-month test period (July 2010 - October 2013). As a future scenario, six check-dams located in the main streams were proposed to reduce sediment and radionuclide delivery. An updated version of Borselli's index of runoff and sediment connectivity was run, using the D-infinity flow accumulation algorithm and exploiting three 0.5-m resolution digital elevation models. On the basis of the pre-FMO scenario, HC increased at catchment scale owing to tree thinning and the new skidding trails. This change was more noticeable within the area affected by the FMO, where HC increased by 11.4% and 10.5% in the cypress and cedar plantations in K2 respectively and by 8.8% in the cedar plantation in K3. At hillslope plot and stream scales, the evolution in the values of HC was less evident, except the increment (by 5.4%) observed in the streams at K2 after the FMO. Progressive vegetation recovery after the FMO triggered a slight reduction of connectivity in all compartments of both subcatchments. Forest roads and especially skidding trails presented the highest values of HC, appearing as the most efficient features connecting the different vegetation patches with the stream network. The spatial

Modelling mean transit time of stream base flow during tropical cyclone rainstorm in a steep relief forested catchment

Science.gov (United States)

Lee, Jun-Yi; Huang, -Chuan, Jr.

2017-04-01

Mean transit time (MTT) is one of the of fundamental catchment descriptors to advance understanding on hydrological, ecological, and biogeochemical processes and improve water resources management. However, there were few documented the base flow partitioning (BFP) and mean transit time within a mountainous catchment in typhoon alley. We used a unique data set of 18O isotope and conductivity composition of rainfall (136 mm to 778 mm) and streamflow water samples collected for 14 tropical cyclone events (during 2011 to 2015) in a steep relief forested catchment (Pinglin, in northern Taiwan). A lumped hydrological model, HBV, considering dispersion model transit time distribution was used to estimate total flow, base flow, and MTT of stream base flow. Linear regression between MTT and hydrometric (precipitation intensity and antecedent precipitation index) variables were used to explore controls on MTT variation. Results revealed that both the simulation performance of total flow and base flow were satisfactory, and the Nash-Sutcliffe model efficiency coefficient of total flow and base flow was 0.848 and 0.732, respectively. The event magnitude increased with the decrease of estimated MTTs. Meanwhile, the estimated MTTs varied 4-21 days with the increase of BFP between 63-92%. The negative correlation between event magnitude and MTT and BFP showed the forcing controls the MTT and BFP. Besides, a negative relationship between MTT and the antecedent precipitation index was also found. In other words, wetter antecedent moisture content more rapidly active the fast flow paths. This approach is well suited for constraining process-based modeling in a range of high precipitation intensity and steep relief forested environments.

Differences in N loading affect DOM dynamics during typhoon events in a forested mountainous catchment.

Science.gov (United States)

Yeh, Tz-Ching; Liao, Chien-Sen; Chen, Ting-Chien; Shih, Yu-Ting; Huang, Jr-Chuan; Zehetner, Franz; Hein, Thomas

2018-03-21

The dissolved organic matter (DOM) and nutrient dynamics in small mountainous rivers (SMRs) strongly depend on hydrologic conditions, and especially on extreme events. Here, we investigated the quantity and quality of DOM and inorganic nutrients during base-flow and typhoon events, in a chronically N-saturated mainstream and low N-loaded tributaries of a forested small mountainous reservoir catchment in Taiwan. Our results suggest that divergent transport mechanisms were triggered in the mainstream vs. tributaries during typhoons. The mainstream DON increased from 3.4 to 34.7% of the TDN pool with a static DOC:NO 3 -N ratio and enhanced DOM freshness, signalling a N-enriched DOM transport. Conversely, DON decreased from 46 to 6% of the TDN pool in the tributaries and was coupled with a rapid increase of the DOC:NO 3 -N ratio and humified DOM signals, suggesting the DON and DOC were passively and simultaneously transported. This study confirmed hydrology and spatial dimensions being the main drivers shaping the composition and concentration of DOM and inorganic nutrients in small mountainous catchments subject to hydrologic extremes. We highlighted that the dominant flow paths largely controlled the N-saturation status and DOM composition within each sub-catchment, the effect of land-use could therefore be obscured. Furthermore, N-saturation status and DOM composition are not only a result of hydrologic dynamics, but potential agents modifying the transport mechanism of solutes export from fluvial systems. We emphasize the importance of viewing elemental dynamics from the perspective of a terrestrial-aquatic continuum; and of taking hydrologic phases and individual catchment characteristics into account in water quality management. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Use of a forest sapwood area index to explain long-term variability in mean annual evapotranspiration and streamflow in moist eucalypt forests

Science.gov (United States)

Benyon, Richard G.; Lane, Patrick N. J.; Jaskierniak, Dominik; Kuczera, George; Haydon, Shane R.

2015-07-01

Mean sapwood thickness, measured in fifteen 73 year old Eucalyptus regnans and E. delegatensis stands, correlated strongly with forest overstorey stocking density (R2 0.72). This curvilinear relationship was used with routine forest stocking density and basal area measurements to estimate sapwood area of the forest overstorey at various times in 15 research catchments in undisturbed and disturbed forests located in the Great Dividing Range, Victoria, Australia. Up to 45 years of annual precipitation and streamflow data available from the 15 catchments were used to examine relationships between mean annual loss (evapotranspiration estimated as mean annual precipitation minus mean annual streamflow), and sapwood area. Catchment mean sapwood area correlated strongly (R2 0.88) with catchment mean annual loss. Variation in sapwood area accounted for 68% more variation in mean annual streamflow than precipitation alone (R2 0.90 compared with R2 0.22). Changes in sapwood area accounted for 96% of the changes in mean annual loss observed after forest thinning or clear-cutting and regeneration. We conclude that forest inventory data can be used reliably to predict spatial and temporal variation in catchment annual losses and streamflow in response to natural and imposed disturbances in even-aged forests. Consequently, recent advances in mapping of sapwood area using airborne light detection and ranging will enable high resolution spatial and temporal mapping of mean annual loss and mean annual streamflow over large areas of forested catchment. This will be particularly beneficial in management of water resources from forested catchments subject to disturbance but lacking reliable long-term (years to decades) streamflow records.

The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: Forest Loss By Year 2001 to 2013

Data.gov (United States)

U.S. Environmental Protection Agency — This dataset represents the characterization of global forest extent and change by year from 2001 through 2013 within individual local NHDPlusV2 catchments and...

Interpretation of concentration‐discharge patterns in acid‐neutralizing capacity during storm flow in three small, forested catchments in Shenandoah National Park, Virginia

Science.gov (United States)

Rice, Karen C.; Chanat, Jeffrey G.; Hornberger, George M.; Webb, James R.

2004-01-01

Episodic concentration‐discharge (c‐Q) plots are a popular tool for interpreting the hydrochemical response of small, forested catchments. Application of the method involves assuming an underlying conceptual model of runoff processes and comparing observed c‐Q looping patterns with those predicted by the model. We analyzed and interpreted c‐Q plots of acid‐neutralizing capacity (ANC) for 133 storms collected over a 7‐year period from three catchments in Shenandoah National Park, Virginia. Because of their underlying lithologies the catchments represent a gradient in both hydrologic and geochemical behavior, ranging from a flashy, acidic, poorly buffered catchment to a moderate, neutral, well‐buffered catchment. The relative frequency of observed anticlockwise c‐Q loops in each catchment decreased along this gradient. Discriminant function analysis indicated that prestorm base flow ANC was an important predictor of loop rotation direction; however, the strength of the predictive relationship decreased along the same gradient. The trends were consistent with several equally plausible three‐component mixing models. Uncertainty regarding end‐member timing and relative volume and possible time variation in end‐member concentrations were key factors precluding identification of a unique model. The inconclusive results obtained on this large data set suggest that identification of underlying runoff mechanisms on the basis of a small number of c‐Q plots without additional supporting evidence is likely to be misleading.

Merging perspectives in the catchment sciences: the US-Japan Joint Seminar on catchment hydrology and forest biogeochemistry

Science.gov (United States)

Kevin J. McGuire; Stephen D. Sebestyen; Nobuhito Ohte; Emily M. Elliott; Takashi Gomi; Mark B. Green; Brian L. McGlynn; Naoko. Tokuchi

2014-01-01

Japan has strong research programmes in the catchment sciences that overlap with interests in the US catchment science community, particularly in experimental and field-based research. Historically, however, there has been limited interaction between these two hydrologic science communities because of differences in language, culture, and research approaches. These...

Lowland forest butterflies of the Sankosh River catchment, Bhutan

Directory of Open Access Journals (Sweden)

A.P. Singh

2012-10-01

Full Text Available This paper provides information on butterflies of the lowland forests of Bhutan for the first time. As a part of the biodiversity impact assessment for the proposed Sankosh hydroelectric power project, a survey was carried out along the Sankosh River catchment to study the butterfly diversity. The aim of the study was to identify species of conservation priority, their seasonality and to know the butterfly diversity potential of the area. Surveys were carried out during five different seasons (winter, spring, pre-monsoon, monsoon, post-monsoon lasting 18 days from January 2009 to March 2010. Pollard walk method was used to assess the diversity on four-line transects within 10-12 km radius of the proposed dam site. Two hundred and thirteen species, including 22 papilionids, were thus sampled. Eleven species amongst these are listed in Schedules I and II of the Indian Wildlife (Protection Act, 1972, of which 10 taxa (Pareronia avatar avatar, Nacaduba pactolus continentalis, Porostas aluta coelestis, Elymnias vasudeva vasudeva, Mycalesis mestra retus, Melanitis zitenius zitenius, Charaxes marmax, Athyma ranga ranga, Neptis manasa manasa and Neptis soma soma are of conservation priority as they are ‘rare’ in occurrence across their distribution range in the region. The maximum number of species (128 were recorded during the spring season (March and lowest (66 during July (monsoon. The seasonal pattern of variation in diversity was very typical of the pattern found in other areas of the lower foothills and adjoining plains of the Himalaya. Relative abundances of butterflies during spring varied significantly (p<0.05 as compared to winter, pre-monsoon and post-monsoon seasons. However, species composition changed with every season as Sorensen’s similarity index varied between 0.3076 to 0.5656. All these findings suggest that the lowland forests of Bhutan hold a rich and unique diversity of butterflies during every season of the year thus having

Assessing colloid-bound metal export in response to short term changes in runoff from a forested catchment

Science.gov (United States)

Neubauer, E.; Kammer, F. v. d.; Knorr, K.-H.; Pfeiffer, S.; Reichert, M.; Hofmann, T.

2012-04-01

Soils can act as a source of metals and natural organic matter (NOM) in runoff from catchments. Amounts and intensity of rainfall may influence NOM export from catchments. The presence of NOM and other colloids in water may not only enhance metal export, but also significantly change metal speciation. In this study, we investigated the response of metal-colloid associations to short-term discharge variations in the runoff from a small forested catchment (Lehstenbach, Bavaria, Germany). Here, the discharge from the catchment outlet responds within hours to rain events. Near-surface flow in organic-rich layers and peat soils has been identified to increase dissolved organic carbon (DOC) concentrations during stormwater runoff. Flow Field-Flow Fractionation coupled to ICP-MS (FlowFFF-ICPMS) is a high-resolution size separation technique which was used for the detection and quantification of colloids and associated metals. Colloid-associated metals, dissolved metals and metals associated with low-molecular weight organic ligands were also separated by filtration (0.2 µm) and ultrafiltration (1000 g/mol MWCO). During baseflow DOC concentration was pH ranged between 4.6 and 5.0. The DOC concentration exported at a given discharge was subject to strong seasonal variation and depended on the water level before the discharge event. DOC concentrations were up to 8 fold higher during stormwater runoff compared to baseflow. The export of aluminum, arsenic, rare earth elements (REE) and uranium from the catchment increased during stormwater runoff showing a strong correlation with NOM concentrations. This result was supported by FlowFFF-ICPMS data revealing that NOM was the only colloid type available for metal complexation during all hydrological conditions. A clear temporal pattern in the association with the NOM was observed for most of the metals under study: During baseflow, 70-100% (Fe), 90% (Al), 60-100% (REE) and 80-85% (U) were associated with the NOM. During

Water yield issues in the jarrah forest of south-western Australia

Science.gov (United States)

Ruprecht, J. K.; Stoneman, G. L.

1993-10-01

The jarrah forest of south-western Australia produces little streamflow from moderate rainfall. Water yield from water supply catchments for Perth, Western Australia, are low, averaging 71 mm (7% of annual rainfall). The low water yields are attributed to the large soil water storage available for continuous use by the forest vegetation. A number of water yield studies in south-western Australia have examined the impact on water yield of land use practices including clearing for agricultural development, forest harvesting and regeneration, forest thinning and bauxite mining. A permanent reduction in forest cover by clearing for agriculture led to permanent increases of water yield of approximately 28% of annual rainfall in a high rainfall catchment. Thinning of a high rainfall catchment led to an increase in water yield of 20% of annual rainfall. However, it is not clear for how long the increased water yield will persist. Forest harvesting and regeneration have led to water yield increases of 16% of annual rainfall. The subsequent recovery of vegetation cover has led to water yields returning to pre-disturbance levels after an estimated 12-15 years. Bauxite mining of a high rainfall catchment led to a water yield increase of 8% of annual rainfall, followed by a return to pre-disturbance water yield after 12 years. The magnitude of specific streamflow generation mechanisms in small catchments subject to forest disturbance vary considerably, typically in a number of distinct stages. The presence of a permanent groundwater discharge area was shown to be instrumental in determining the magnitude of the streamflow response after forest disturbance. The long-term prognosis for water yield from areas subject to forest thinning, harvesting and regeneration, and bauxite mining are uncertain, owing to the complex interrelationship between vegetation cover, tree height and age, and catchment evapotranspiration. Management of the forest for water yield needs to acknowledge

The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) Riparian Buffer for the Conterminous United States: Forest Loss By Year 2001 to 2013

Data.gov (United States)

U.S. Environmental Protection Agency — This dataset represents the characterization of global forest extent and change by year from 2001 through 2013 within individual local NHDPlusV2 catchments and...

Analysis and Model Based Assessment of Water Quality in European Mesoscale Forest Catchments with Different Management Strategies (a Climatic Gradient Approach)

Science.gov (United States)

Tavares, Filipa; Schwaerzel, Kai; Nunes, João. Pedro; Feger, Karl-Heinz

2010-05-01

Forestry activities affect the environmental conditions of river basins by modifying soil properties and vegetation cover, leading to changes in e.g. runoff generation and routing, water yield or the trophic status of water bodies. Climate change is directly linked to forestry, since site-adapted sustainable forest management can buffer negative climate change impacts in river basins, while practices leading to over-harvesting or increasing wildfires can exacerbate these impacts. While studies relating hydrological processes with forestry practices or climate change have already been conducted, the combined impacts of both are rarely discussed. The main objective of the proposed work is to study the interactions between forest management and climate change and the effects of these upon water fluxes and water quality at the catchment scale, over medium to long-term periods and following an East-West climate gradient. Additional objectives are to increase knowledge about the relations between forest, water quality and soil conservation/degradation; and to improve the modelling of hydrological and matter transport processes in managed forests. The present poster shows a conceptual approach to understand this combined interaction by analysing an East-West climatic gradient (Ukraine-Germany-Portugal), with contrasting forestry practices and climate vulnerabilities. The activities within this workplan, to take place during the period 2010 - 2014, will be developed in close collaboration with several ongoing research projects in the host institution at the Dresden University of Technology (TUD) and in the University of Aveiro (UA). The Institute of Soil Science and Site-Ecology (ISSE) at TUD has an internationally renowned research tradition in forest hydrological topics using methods and findings from various (sub)disciplines in a multidisplinary approach. The measurement and simulation of forest catchments has also been a point of research at the Centre for

Temporal change of SF6 age in spring during rainstorms in a forested headwater catchment, Fukushima, Japan

Science.gov (United States)

Sakakibara, Koichi; Tsujimura, Maki; Onda, Yuichi; Iwagami, Sho; Sato, Yutaro; Nagano, Kosuke

2017-04-01

Time variant water age in catchments can fundamentally describe catchment function, controlling rainfall-runoff generation, groundwater flow pathway, and water storage. We observed sulfur hexafluoride concentration in the stream and groundwater with 1 - 2 hours interval during rainstorm events in order to reveal temporal variations of rainfall-runoff water age. Target's spring is perennial in a forested headwater catchment with an area of 0.045 square km, Fukushima, Japan. The observed hydrological data and tracer data of water in the catchment (stable isotopic compositions, inorganic solute concentrations) were used for clarifying rainfall-runoff processes related to water age variances. The storm hydrograph and groundwater table clearly responded to rainfall especially with more than 30 mm per day throughout the monitoring period (May 2015 - October 2016). Large variations of SF6 age in spring ranging from zero to 14 years were found in the short period during rainstorms. In particular, the SF6 age in spring was evidently old when the runoff was over 2 mm per day. At the high runoff condition, the SF6 age in spring positively correlated with discharge rate: the spring age became older as the discharge rate increased. With regard to spatial distributions of SF6 age in groundwater, the old groundwater age (9 - 13 years) in the shallow subsurface area along the valley was confirmed after heavy rainfall. This groundwater age was similar age to the deep groundwater at no-rainfall conditions. In addition, inorganic solute concentrations such as chloride ion, sodium ion, and silica in spring water showed dominant levels in the deep and ridge groundwater. All facts suggest that the old groundwater, stored in the ridge or deeper subsurface area, replaced the shallow groundwater in the vicinity of the spring due to heavy rainfall, then it contributed to the spring discharge. Therefore, rainstorm events play important roles as triggers for discharging older water stored in

Effects of acidified drinking water on the teeth of laboratory mice

OpenAIRE

Kostov, Marko

2013-01-01

The aim of this investigation was to determine the effects of hydrochloric acid used as hygienic measure in drinking water (pH2) on teeth of conventional and germfree laboratory mice. Four groups of 10 animals each were used. Group 1 : Conventional animals (tap water) Group 2 : Conventional animals (tap water, acidified ) Group 3 : Germfree animals (tap water, sterilized ) Group 4 : Germfree animals (tap water , acidified, sterilized ) The application of acidified drinking ...

Granulated wood ash to forest soil - Ecological effects

International Nuclear Information System (INIS)

Rosen, K.; Eriksson, H.; Clarholm, M.; Lundkvist, H.; Rudebeck, A.

1993-01-01

This report describes research concerning ecological effects of wood ash recycling to forest soils. The main part of the minerals in the wood fuels are retained in the ashes after combustion. By returning the ashes back to the cleared forest areas, the mineral losses can be reduced. Adding ashes and limestone is a method to vitalize acidified forest soils and restore the production capacity. 48 refs, 26 figs, 8 tabs

Water quality improvements from afforestation in an agricultural catchment in Denmark illustrated with the INCA model

DEFF Research Database (Denmark)

Bastrup-Birk, A.; Gundersen, P.

2004-01-01

Intensive agricultural land use across Europe has altered nitrogen (N) budget of catchments substantially, causing widespread N pollution of freshwater. Although the N cycle in forests has changed due to increased N deposition, most forest soil waters in Europe have low nitrate concentrations...... was then used to simulate the effect of afforestation of a catchment dominated by agriculture on N fluxes with seepage and runoff. Scenarios of whole catchment conversion to forest were run, based on observations of evapotranspiration and N deposition from other Danish sites. The simulated conversion to mature...... forest reduced runoff by 30–45% and reduced the nitrate concentrations in the soil water by 50–70%. The simulated effect of afforestation on N leaching was an almost direct reflection of the change in the N input: substantial changes in the plant demand and soil N dynamics over the afforestation period...

Determining hillslope-channel connectivity in an agricultural catchment using rare-earth oxide tracers and random forests.

Science.gov (United States)

Masselink, Rens; Temme, Arnaud; Giménez, Rafael; Casalí, Javier; Keesstra, Saskia

2017-04-01

Soil erosion from agricultural areas is a large problem, because of off-site effects like the rapid filling of reservoirs. To mitigate the problem of sediments from agricultural areas reaching the channel, reservoirs and other surface waters, it is important to understand hillslope-channel connectivity and catchment connectivity. To determine the functioning of hillslope-channel connectivity and the continuation of transport of these sediments in the channel, it is necessary to obtain data on sediment transport from the hillslopes to the channels. Simultaneously, the factors that influence sediment export out of the catchment need to be studied. For measuring hillslope-channel sediment connectivity, Rare-Earth Oxide (REO) tracers were applied to a hillslope in an agricultural catchment in Navarre, Spain, preceding the winter of 2014-2015. The results showed that during the winter there was no sediment transport from the hillslope to the channel. Analysis of precipitation data showed that total precipitation quantities did not differ much from the mean. However, precipitation intensities were low, causing little sediment mobilisation. To test the implication of the REO results at the catchment scale, two conceptual models for sediment connectivity were assessed using a Random Forest (RF) machine learning method. One model proposes that small events provide sediment for large events, while the other proposes that only large events cause sediment detachment and small events subsequently remove these sediments from near and in the channel. The RF method was applied to a daily dataset of sediment yield from the catchment (N=2451 days), and two subsets of the whole dataset: small events (N=2319) and large events (N=132). For sediment yield prediction of small events, variables related to large preceding events were the most important. The model for large events underperformed and, therefore, we could not draw any immediate conclusions whether small events influence the

Sediment budgets of mountain catchments: Scale dependence and the influence of land-use

Science.gov (United States)

Förster, Helga; Dotterweich, Markus; Wunderlich, Jürgen

2010-05-01

Long-term sediment budgets of forested mountain catchments are scarcely investigated today. This is because they are traditionally expected to show few erosion features and low sediment delivery. This opinion originates from process-based hydrological studies proving the runoff preventing properties of trees and forest soils. In addition mountain areas have been colonized later and only sporadically compared to the fruitful loess-covered lowlands. On the other hand steep hillslopes, narrow valleys and the availability of regolith cause a high erosion potential. And there is evidence that historical floods and yearly occurring storms initiate intensive but local and sporadic erosion events. Sediment budgets from zero-order catchments of the Palatinate Forest in the south-western sandstone escarpment in Rhineland-Palatinate show spatially varying intensities of land use impact and relief conditions. The budgets are based on field data and a soilscape model of an upper periglacial cover bed with a homogenous thickness. OSL- and 14C-dates of colluvial deposits allow relating erosion events to land-use changes derived from historical maps and written archives. The presented case studies from the Palatinate Forest are of special interest as the high proximity to the loess-covered and intensively cultivated Rhine Graben effected settlement and land-use intensity in the mountain catchments. Clear cuts for settlements were joined by deforestation for agriculture and stretched mainly along the Haardtrand and high order valleys. Off these areas the strength of interference in the forest ecosystem depended on transport possibilities and distance to the Rhine Graben. In the vicinity strong devastation and clear cutting occurred. With increasing distance the felling intensity decreased and some parts seem to be nearly undisturbed until the 18th century. The needs for wood were controlled by the economical development as well as political decisions on local to European scale. The

Do agricultural terraces and forest fires recurrence in Mediterranean afforested micro-catchments alter soil quality and soil nutrient content?

Science.gov (United States)

E Lucas-Borja, Manuel; Calsamiglia, Aleix; Fortesa, Josep; García-Comendador, Julián; Gago, Jorge; Estrany, Joan

2017-04-01

Bioclimatic characteristics and intense human pressure promote Mediterranean ecosystems to be fire-prone. Afforestation processes resulting from the progressive land abandonment during the last decades led to greater biomass availability increasing the risk of large forest fires. Likewise, the abandonment and lack of maintenance in the terraced lands constitute a risk of land degradation in terms of soil quantity and quality. Despite the effects of fire and the abandonment of terraced lands on soil loss and physico-chemical properties are identified, it is not clearly understood how wildfires and abandonment of terraces affect soil quality and nutrients content. Microbiological soil parameters and soil enzymes activities are biomarkers of the soil microbial communitýs functional ability, which potentially enables them as indicators of change, disturbance or stress within the soil community. The objective of this study was to investigate the effects of terracing (abandoned and non-abandoned) on the soil enzyme activities, microbiological soil parameters and soil nutrients dynamics in three Mediterranean afforested micro-catchments (i.e., fire recurrence in the last 20 years; i.e., unburned areas, burned once and burned twice. The combination of the presence of terraces and the recurrence of forest fire, thirty-six plots of 25 m2 were sampled along the these three micro-catchments collecting four replicas at the corners of each plot. The results elucidated how non-terraced and unburned plots presented the highest values of soil respiration rate and extracellular soil enzymes. Differences between experimental plots with different forest fire recurrence or comparing terraced and unburned plots with burned plots were weaker in relation to biochemical and microbiological parameters. Soil nutrient content showed an opposite trend with higher values in terraced plots, although differences were weaker. We conclude that terraced landscapes present poorer soil quality

Techniques for assessing the effects of afforestation on catchment hydrology: the South African experience

CSIR Research Space (South Africa)

Dye, PJ

2006-08-01

Full Text Available research into the effects of forest plantations on catchment hydrology. This paper provides a brief overview of some of the techniques employed by South African hydrological researchers to understand the link between afforestation and catchment water yields....

The role of land use and soils in regulating water flow in small headwater catchments of the Andes

Science.gov (United States)

Roa-GarcíA, M. C.; Brown, S.; Schreier, H.; Lavkulich, L. M.

2011-05-01

Land use changes can have a significant impact on the terrestrial component of the water cycle. This study provides a comparison of three small headwater catchments in the Andean mountains of Colombia with different composition of land use. Several methods were used to quantify differences in the hydrological behavior of these catchments such as flow duration curves, stormflow analysis, and the linear reservoir concept. They were combined with an analysis of the characteristics of soils that contribute to understanding the aggregate catchment hydrological behavior. Andisols, which are soils formed in volcanic areas and with a large capacity to hold water, amplify differences in land use and limit the potential impact of land use management activities (conservation or restoration) on the water regulation function of catchments. Of the three studied catchments, less variability of flows was observed from the catchment with a larger percentage of area in forest, and a slower decrease of flows in the dry season was observed for the catchment with a relatively higher percentage of area in wetlands. Evidence is provided for the infiltration trade-off hypothesis for tropical environments, which states that after forest removal, soil infiltration rates are smaller and the water losses through quick flow are larger than the gains by reduced evapotranspiration; this is compatible with the results of the application of the linear reservoir concept showing a faster release of water for the least forested catchment.

Water quality improvements from afforestation in an agricultural catchment in Denmark illustrated with the INCA model

Directory of Open Access Journals (Sweden)

A. Bastrup-Birk

2004-01-01

Full Text Available Intensive agricultural land use across Europe has altered nitrogen (N budget of catchments substantially, causing widespread N pollution of freshwater. Although the N cycle in forests has changed due to increased N deposition, most forest soil waters in Europe have low nitrate concentrations. The protective function of forests on water quality has led to increasing interest in the planting of new forests on arable land as a measure to protect valuable or sensitive freshwater resources. The paper illustrates the effects of afforestation on water and N cycling using the Integrated Nitrogen Catchment (INCA model. The model was calibrated on the Horndrup catchment in the eastern part of Jutland, Denmark, which is dominated by agricultural land use but also covered by 18% of forest land. The dynamics of nitrate concentrations in the stream water were simulated successfully by INCA over a three-year period. The simulation of the dynamics of nitrate concentrations in the soil water is closely linked to the simulation of the hydrological dynamics and especially to the rainfall. The best fit was achieved for both arable and forest land during the wettest year of the study period. The model was then used to simulate the effect of afforestation of a catchment dominated by agriculture on N fluxes with seepage and runoff. Scenarios of whole catchment conversion to forest were run, based on observations of evapotranspiration and N deposition from other Danish sites. The simulated conversion to mature forest reduced runoff by 30–45% and reduced the nitrate concentrations in the soil water by 50–70%. The simulated effect of afforestation on N leaching was an almost direct reflection of the change in the N input: substantial changes in the plant demand and soil N dynamics over the afforestation period were not simulated. To simulate the N dynamics over longer time-scales, appropriate for the study of afforestation, it is suggested that the INCA model be run

Use of 15N-labelled nitrogen deposition to quantify the source of nitrogen in runoff at a coniferous-forested catchment at Gardsjoen, Sweden

International Nuclear Information System (INIS)

Kjonaas, O. Janne; Wright, Richard F.

2007-01-01

To determine the source of dissolved inorganic nitrogen (N) in runoff, approx. 35 kg N enriched with the stable isotope 15 N (2110 per mille δ 15 N) was added to a mature coniferous forested catchment for one whole year. The total N input was approx. 50 kg ha -1 year -1 . The enrichment study was part of a long-term whole-catchment ammonium nitrate addition experiment at Gardsjoen, Sweden. The 15 N concentrations in precipitation, throughfall, runoff and upper forest floor were measured prior to, during, and 3-9 years following the 15 N addition. During the year of the 15 N addition the δ 15 N level in runoff largely reflected the level in incoming N, indicating that the leached NO 3 - came predominantly from precipitation. Only 1.1% of the incoming N was lost during the year of the tracer addition. The cumulative loss of tracer N over a 10-year period was only 3.9% as DIN and 1.1% as DON. - 15 N tracer addition showed that initially the main source of NO 3 - in runoff was N from atmospheric deposition

Quantifying the contributions of sediment, sediment-P and fertiliser-P from forested, cultivated and pasture areas at the landuse and catchment scale using fallout radionuclides and geochemistry

International Nuclear Information System (INIS)

Wallbrink, P.J.; Martin, C.E.; Wilson, C.J.

2003-01-01

In this paper we use a combination of fallout nuclides and geochemistry to determine the contributions of sediment and sediment bound phosphorus (sed-P) from the major diffuse sources in the Bundella Creek catchment (8700 ha), NSW, Australia. Sources include surface erosion from cultivated, pasture and steep forested land as well as subsoil erosion from channels and gullies. We determine these contributions to the <10 μm fraction of deposited sediments. Concentrations of P were higher in the surface soils of each landuse than the underlying subsoils, and erosion from these contributed more to offsite sediment-P (∼60%) than did subsoil erosion at the individual landuse scale. At the catchment outlet, the amount of surface sediment eroded from cultivated lands was a factor of ∼84 higher than from pastures; the steep forested lands contributed ∼9 times more than pastures. Sed-P eroded from cultivated land was ∼42 times higher than from pasturelands; the forests were ∼8 times greater than from pastures. At the catchment outlet the largest contribution of sediment (∼70%) and sed-P (∼62%) was from subsoil erosion of gullies and channels within and between the different landuse areas. There was little contribution of sediment or sed-P at the catchment scale from surface erosion of pastures. Concentrations of P were highest in 'storm event' suspended sediment samples taken from the pasture and cultivated areas without gullies. In a suite of samples selected for their high P contents, fertiliser P was detected in two storm event suspended sediment samples and one deposited sediment sample, using the ratio of Nd/P. This suggests fertiliser P may be transported-off land surfaces with sediments and contribute to offsite sediment-P concentrations in some situations. However, the fertiliser contributions were episodic and variable; and probably influenced by particle size selectivity as well as timing of fertiliser application with respect to size and occurrence

Soils, water and nutrients in a forest ecosystem in Suriname

NARCIS (Netherlands)

Poels, R.L.H.

1987-01-01

Water and nutrient flows were measured in catchments on strongly weathered loamy sediments of the Zanderij formation in Suriname under undisturbed forest and forest silviculturally treated whereby 40 % of the biomass was killed. The topography of the two catchment areas studied (each of

Assessing catchment connectivity using hysteretic loops

Science.gov (United States)

Davis, Jason; Masselink, Rens; Goni, Mikel; Gimenez, Rafael; Casali, Javier; Seeger, Manuel; Keesstra, Saskia

2017-04-01

texture topsoil), climate (humid sub Mediterranean) and land use (80-90% cultivated with winter grain crops). Ozkotz principal (ca.1,700 ha) is covered with forest and pasture (cattle-breeding); while Oskotz woodland (ca. 500 ha), a sub-watershed of the Oskotz principal, is almost completely covered with forest. The predominant climate in the Oskotz catchments sub-Atlantic. Furthermore, antecedent conditions and event characteristics were analysed. The loops were compared quantitatively and qualitatively between catchments for similar events and within the catchments for events with different characteristics. In this study, several measures to objectively classify hysteresis loops in an automated way were developed. These were consecutively used to classify several hundreds of loops from several agricultural catchments in Northern Spain. These loop characteristics were compared to event specific characteristics such as antecedent precipitation, time of year, and precipitation intensity, duration and total. The combination of hysteresis loops and variables influencing connectivity can then tell something about the sources of sediments for different events and catchments. References Baartman, J.E.M., Masselink, R.H., Keesstra, S.D., Temme, A.J.A.M., 2013. Linking landscape morphological complexity and sediment connectivity. Earth Surface Processes and Landforms 38: 1457-1471. Masselink RJH, Heckmann T, Temme AJAM, Anders NS, Gooren HPA, Keesstra SD. 2016. A network theory approach for a better understanding of overland flow connectivity. Hydrological Processes. DOI: 10.1002/hyp.10993 Masselink, R.J.H., Keesstra, S.D., Temme, A.J.A.M., Seeger, M., Giménez, R., Casalí, J., 2016. Modelling Discharge and Sediment Yield at Catchment Scale Using Connectivity Components. Land Degradation and Development 27: 933-945, DOI: 10.1002/ldr.2512 Mekonnen, M., Keesstra, S.D., Baartman, J.E.M., Stroosnijder, L., Maroulis, J., Reducing sediment connectivity through man-made and natural

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

organic carbon (DOC) concentrations were positively correlated with discharge from forested catchments over the year. While the overall concentrations of DOC were several times higher in the southern two catchments, higher discharge in the northern catchment resulted in the annual loadings of DOC being...

Application of lime (CaCO3) to promote forest recovery from severe acidification increases potential for earthworm invasion

Science.gov (United States)

Homan, Caitlin; Beirer, Colin M; McCay, Timothy S; Lawrence, Gregory B.

2016-01-01

The application of lime (calcium carbonate) may be a cost-effective strategy to promote forest ecosystem recovery from acid impairment, under contemporary low levels of acidic deposition. However, liming acidified soils may create more suitable habitat for invasive earthworms that cause significant damage to forest floor communities and may disrupt ecosystem processes. We investigated the potential effects of liming in acidified soils where earthworms are rare in conjunction with a whole-ecosystem liming experiment in the chronically acidified forests of the western Adirondacks (USA). Using a microcosm experiment that replicated the whole-ecosystem treatment, we evaluated effects of soil liming on Lumbricus terrestris survivorship and biomass growth. We found that a moderate lime application (raising pH from 3.1 to 3.7) dramatically increased survival and biomass of L. terrestris, likely via increases in soil pH and associated reductions in inorganic aluminum, a known toxin. Very few L. terrestris individuals survived in unlimed soils, whereas earthworms in limed soils survived, grew, and rapidly consumed leaf litter. We supplemented this experiment with field surveys of extant earthworm communities along a gradient of soil pH in Adirondack hardwood forests, ranging from severely acidified (pH 5). In the field, no earthworms were observed where soil pH 4.4 and human dispersal vectors, including proximity to roads and public fishing access, were most prevalent. Overall our results suggest that moderate lime additions can be sufficient to increase earthworm invasion risk where dispersal vectors are present.

Prediction of Baseflow Index of Catchments using Machine Learning Algorithms

Science.gov (United States)

Yadav, B.; Hatfield, K.

2017-12-01

We present the results of eight machine learning techniques for predicting the baseflow index (BFI) of ungauged basins using a surrogate of catchment scale climate and physiographic data. The tested algorithms include ordinary least squares, ridge regression, least absolute shrinkage and selection operator (lasso), elasticnet, support vector machine, gradient boosted regression trees, random forests, and extremely randomized trees. Our work seeks to identify the dominant controls of BFI that can be readily obtained from ancillary geospatial databases and remote sensing measurements, such that the developed techniques can be extended to ungauged catchments. More than 800 gauged catchments spanning the continental United States were selected to develop the general methodology. The BFI calculation was based on the baseflow separated from daily streamflow hydrograph using HYSEP filter. The surrogate catchment attributes were compiled from multiple sources including digital elevation model, soil, landuse, climate data, other publicly available ancillary and geospatial data. 80% catchments were used to train the ML algorithms, and the remaining 20% of the catchments were used as an independent test set to measure the generalization performance of fitted models. A k-fold cross-validation using exhaustive grid search was used to fit the hyperparameters of each model. Initial model development was based on 19 independent variables, but after variable selection and feature ranking, we generated revised sparse models of BFI prediction that are based on only six catchment attributes. These key predictive variables selected after the careful evaluation of bias-variance tradeoff include average catchment elevation, slope, fraction of sand, permeability, temperature, and precipitation. The most promising algorithms exceeding an accuracy score (r-square) of 0.7 on test data include support vector machine, gradient boosted regression trees, random forests, and extremely randomized

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.

Landscape-Scale Disturbance: Insights into the Complexity of Catchment Hydrology in the Mountaintop Removal Mining Region of the Eastern United States

Directory of Open Access Journals (Sweden)

Andrew J. Miller

2016-07-01

Full Text Available Few land disturbances impact watersheds at the scale and extent of mountaintop removal mining (MTM. This practice removes forests, soils and bedrock to gain access to underground coal that results in likely permanent and wholesale changes that impact catchment hydrology, geochemistry and ecosystem health. MTM is the dominant driver of land cover changes in the central Appalachian Mountains region of the United States, converting forests to mine lands and burying headwater streams. Despite its dominance on the landscape, determining the hydrological impacts of MTM is complicated by underground coal mines that significantly alter groundwater hydrology. To provide insight into how coal mining impacts headwater catchments, we compared the hydrologic responses of an MTM and forested catchment using event rainfall-runoff analysis, modeling and isotopic approaches. Despite similar rainfall characteristics, hydrology in the two catchments differed in significant ways, but both catchments demonstrated threshold-mediated hydrologic behavior that was attributed to transient storage and the release of runoff from underground mines. Results suggest that underground mines are important controls for runoff generation in both obviously disturbed and seemingly undisturbed catchments and interact in uncertain ways with disturbance from MTM. This paper summarizes our results and demonstrates the complexity of catchment hydrology in the MTM region.

Jonkershoek research catchments: history and impacts on commercial forestry in South Africa.

CSIR Research Space (South Africa)

Chapman, A

2007-09-01

Full Text Available conservation and allied problems” was endorsed by the 1935 Fourth Empire Forestry Conference held in Cape Town. By 1936 construction was underway on weirs in the Jonkershoek State Forest and a programme of research was developed, with Dr CL Wicht as Founder... collected within these research catchments. Other national impacts include: • Regulation of the R22 billion/a forest industry. The commercial forest industry today derives benefit in export markets from the Sustainable Forest Certification (FSC...

Forests growing under dry conditions have higher hydrological resilience to drought than do more humid forests.

Science.gov (United States)

Helman, David; Lensky, Itamar M; Yakir, Dan; Osem, Yagil

2017-07-01

More frequent and intense droughts are projected during the next century, potentially changing the hydrological balances in many forested catchments. Although the impacts of droughts on forest functionality have been vastly studied, little attention has been given to studying the effect of droughts on forest hydrology. Here, we use the Budyko framework and two recently introduced Budyko metrics (deviation and elasticity) to study the changes in the water yields (rainfall minus evapotranspiration) of forested catchments following a climatic drought (2006-2010) in pine forests distributed along a rainfall gradient (P = 280-820 mm yr -1 ) in the Eastern Mediterranean (aridity factor = 0.17-0.56). We use a satellite-based model and meteorological information to calculate the Budyko metrics. The relative water yield ranged from 48% to 8% (from the rainfall) in humid to dry forests and was mainly associated with rainfall amount (increasing with increased rainfall amount) and bedrock type (higher on hard bedrocks). Forest elasticity was larger in forests growing under drier conditions, implying that drier forests have more predictable responses to drought, according to the Budyko framework, compared to forests growing under more humid conditions. In this context, younger forests were shown more elastic than older forests. Dynamic deviation, which is defined as the water yield departure from the Budyko curve, was positive in all forests (i.e., less-than-expected water yields according to Budyko's curve), increasing with drought severity, suggesting lower hydrological resistance to drought in forests suffering from larger rainfall reductions. However, the dynamic deviation significantly decreased in forests that experienced relatively cooler conditions during the drought period. Our results suggest that forests growing under permanent dry conditions might develop a range of hydrological and eco-physiological adjustments to drought leading to higher hydrological

Estimating sedimentation rates and sources in a partially urbanized catchment using caesium-137

Science.gov (United States)

Ormerod, L. M.

1998-06-01

While there has been increased interest in determining sedimentation rates and sources in agricultural and forested catchments in recent years, there have been few studies dealing with urbanized catchments. A study of sedimentation rates and sources within channel and floodplain deposits of a partially urbanized catchment has been undertaken using the 137Cs technique. Results for sedimentation rates showed no particular downstream pattern. This may be partially explained by underestimation of sedimentation rates at some sites by failure to sample the full 137Cs profile, floodplain erosion and deliberate removal of sediment. Evidence of lateral increases in net sedimentation rates with distance from the channel may be explained by increased floodplain erosion at sites closer to the channel and floodplain formation by lateral deposition. Potential sediment sources for the catchment were considered to be forest topsoil, subsurface material and sediments derived from urban areas, which were found to be predominantly subsurface material. Tracing techniques showed an increase in subsurface material for downstream sites, confirming expectations that subsurface material would increase in the downstream direction in response to the direct and indirect effects of urbanization.

Changes in stream nitrate concentrations due to land management practices, ecological succession, and climate: Developing a system approach to integrated catchment response

Science.gov (United States)

F. Worrall; Wayne T. Swank; T. P. Burt

2003-01-01

This study uses time series analysis to examine long-term stream water nitrate concentration records from a pair of forested catchments at the Coweeta Hydrologic Laboratory, North Carolina, USA. Monthly average concentrations were available from 1970 through 1997 for two forested catchments, one of which was clear-felled in 1977 and the other maintained as a control....

stream nutrient uptake, forest succession, and biogeochemical theory

OpenAIRE

Valett, H. M.; Crenshaw, C. L.; Wagner, P. F.

2002-01-01

Theories of forest succession predict a close relationship between net biomass increment and catchment nutrient retention. Retention, therefore, is expected to be greatest during aggrading phases of forest succession. In general, studies of this type have compared watershed retention efficiency by monitoring stream nutrient export at the base of the catchment. As such, streams are viewed only as transport systems. Contrary to this view, the nutrient spiraling concept emphasizes transformation...

Manganese Biogeochemistry in a Central Czech Republic Catchment

Czech Academy of Sciences Publication Activity Database

Navrátil, Tomáš; Shanley, J. B.; Krám, P.; Mihaljevič, M.; Drahota, Petr

2007-01-01

Roč. 186, 1-4 (2007), s. 149-165 ISSN 0049-6979 R&D Projects: GA ČR GA205/04/0060 Institutional research plan: CEZ:AV0Z30130516 Keywords : manganese * catchment * weathering * biogeochemistry * biotite weathering * forest ecosystem * mass balance Subject RIV: DD - Geochemistry Impact factor: 1.224, year: 2007

Statistical modeling/optimization and process intensification of microwave-assisted acidified oil esterification

International Nuclear Information System (INIS)

Ma, Lingling; Lv, Enmin; Du, Lixiong; Lu, Jie; Ding, Jincheng

2016-01-01

Highlights: • Microwave irradiation was employed for the esterification of acidified oil. • Optimization and modeling of the process was performed by RSM and ANN. • Both models have reliable prediction abilities but the ANN was superior over the RSM. • Membrane vapor permeation and in-situ dehydration were used to shift the equilibrium. • Two dehydration approaches improved the FFAs conversion rate by 20.0% approximately. - Abstract: The esterification of acidified oil with ethanol under microwave radiation was modeled and optimized using response surface methodology (RSM) and artificial neural network (ANN). The impacts of mass ratio of ethanol to acidified oil, catalyst loading, microwave power and reaction time are evaluated by Box-Behnken design (BBD) of RSM and multi-layer perceptron (MLP) of ANN. RSM combined with BBD shows the optimal conditions as catalyst loading of 5.85 g, mass ratio of ethanol to acidified oil of 0.35 (20.0 g acidified oil), microwave power of 328 W and reaction time of 98.0 min with the free fatty acids (FFAs) conversion of 78.57%. Both of the models are fitted well with the experimental data, however, ANN exhibits better prediction accuracy than RSM based on the statistical analyses. Furthermore, membrane vapor permeation and in-situ molecular sieve dehydration were investigated to enhance the esterification under the optimized conditions.

Export of nutrients and major ionic solutes from a rain forest catchment in the Central Amazon Basin

Science.gov (United States)

Lesack, Lance F. W.

1993-03-01

The relative roles of base flow runoff versus storm flow runoff versus subsurface outflow in controlling total export of solutes from a 23.4-ha catchment of undisturbed rain forest in the central Amazon Basin were evaluated from water and solute flux measurements performed over a 1 year period. Solutes exported via 173 storms during the study were estimated from stream water samples collected during base flow conditions and during eight storms, and by utilizing a hydrograph separation technique in combination with a mixing model to partition storm flow from base flow fluxes. Solutes exported by subsurface outflow were estimated from groundwater samples from three nests of piezometers installed into the streambed, and concurrent measurements of hydraulic conductivity and hydraulic head gradients. Base flow discharge represented 92% of water outflow from the basin and was the dominant pathway of solute export. Although storm flow discharge represented only 5% of total water outflow, storm flow solute fluxes represented up to 25% of the total annual export flux, though for many solutes the portion was less. Subsurface outflow represented only 2.5% of total water outflow, and subsurface solute fluxes never represented more than 5% of the total annual export flux. Measurement errors were relatively high for storm flow and subsurface outflow fluxes, but cumulative measurement errors associated with the total solute fluxes exported from the catchment, in most cases, ranged from only ±7% to 14% because base flow fluxes were measured relatively well. The export fluxes of most solutes are substantially less than previously reported for comparable small catchments in the Amazon basin, and these differences cannot be reconciled by the fact that storm flow and subsurface outflows were not appropriately measured in previous studies.

The Value of Long-Term Research at the Five USGS WEBB Catchments

Science.gov (United States)

Shanley, J. B.; Murphy, S. F.; Scholl, M. A.; Wickland, K.; Aulenbach, B. T.; Hunt, R.; Clow, D. W.

2017-12-01

Long-term catchment studies are sentinel sites for detecting, documenting, and understanding ecosystem processes and environmental change. The small catchment approach fosters in-depth site-based hydrological, biogeochemical, and ecological process understanding, while a collective network of catchment observatories offers a broader context to synthesize understanding across a range of climates and geologies. The USGS Water, Energy, and Biogeochemical Budgets (WEBB) program is a network of five sites established in 1991 to assess the impact of climate and environmental change on hydrology and biogeochemistry. Like other networks, such as the USDA - Forest Service Experimental Forests and the Czech Geomon network, WEBB exploits gradients of climate, geology, and topography to understand controls on biogeochemical processes. We present examples from each site and some cross-site syntheses to demonstrate how WEBB has advanced catchment science and informed resource management and policy. WEBB has relied on strong academic partnerships, providing long-term continuity for shorter-term academic grants, which have offered rich graduate educational opportunities. Like other sites and networks, the long-term datasets and process understanding of WEBB provide context to detect and interpret change. Without this backdrop, we have no baseline to quantify effects of droughts, floods, and extreme events, and no test sites to validate process-based models. In an era of lean budgets for science funding, the long-term continuity of WEBB and other catchment networks is in jeopardy, as is the critical scientific value and societal benefits they embody.

Impacts of forest age on water use in Mountain ash forests

Science.gov (United States)

Wood, Stephen A.; Beringer, Jason; Hutley, Lindsay B.; McGuire, A. David; Van Dijk, Albert; Kilinc, Musa

2008-01-01

Runoff from mountain ash (Eucalyptus regnans F.Muell.) forested catchments has been shown to decline significantly in the few decades following fire returning to pre-fire levels in the following centuries owing to changes in ecosystem water use with stand age in a relationship known as Kuczera's model. We examined this relationship between catchment runoff and stand age by measuring whole-ecosystem exchanges of water using an eddy covariance system measuring forest evapotranspiration (ET) combined with sap-flow measurements of tree water use, with measurements made across a chronosequence of three sites (24, 80 and 296 years since fire). At the 296-year old site eddy covariance systems were installed above the E. regnans overstorey and above the distinct rainforest understorey. Contrary to predictions from the Kuczera curve, we found that measurements of whole-forest ET decreased by far less across stand age between 24 and 296 years. Although the overstorey tree water use declined by 1.8mmday-1 with increasing forest age (an annual decrease of 657mm) the understorey ET contributed between 1.2 and 1.5mmday-1, 45% of the total ET (3mmday-1) at the old growth forest.

21 CFR 108.25 - Acidified foods.

Science.gov (United States)

2010-04-01

... Administration on Form FDA 2541 (food canning establishment registration) information including, but not limited... continuous inspection of the meat and poultry inspection program of the Food Safety and Inspection Service of... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Acidified foods. 108.25 Section 108.25 Food and...

Climatic and Catchment-Scale Predictors of Chinese Stream Insect Richness Differ between Taxonomic Groups.

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Jonathan D Tonkin

Full Text Available Little work has been done on large-scale patterns of stream insect richness in China. We explored the influence of climatic and catchment-scale factors on stream insect (Ephemeroptera, Plecoptera, Trichoptera; EPT richness across mid-latitude China. We assessed the predictive ability of climatic, catchment land cover and physical structure variables on genus richness of EPT, both individually and combined, in 80 mid-latitude Chinese streams, spanning a 3899-m altitudinal gradient. We performed analyses using boosted regression trees and explored the nature of their influence on richness patterns. The relative importance of climate, land cover, and physical factors on stream insect richness varied considerably between the three orders, and while important for Ephemeroptera and Plecoptera, latitude did not improve model fit for any of the groups. EPT richness was linked with areas comprising high forest cover, elevation and slope, large catchments and low temperatures. Ephemeroptera favoured areas with high forest cover, medium-to-large catchment sizes, high temperature seasonality, and low potential evapotranspiration. Plecoptera richness was linked with low temperature seasonality and annual mean, and high slope, elevation and warm-season rainfall. Finally, Trichoptera favoured high elevation areas, with high forest cover, and low mean annual temperature, seasonality and aridity. Our findings highlight the variable role that catchment land cover, physical properties and climatic influences have on stream insect richness. This is one of the first studies of its kind in Chinese streams, thus we set the scene for more in-depth assessments of stream insect richness across broader spatial scales in China, but stress the importance of improving data availability and consistency through time.

Climatic and Catchment-Scale Predictors of Chinese Stream Insect Richness Differ between Taxonomic Groups

Science.gov (United States)

Tonkin, Jonathan D.; Shah, Deep Narayan; Kuemmerlen, Mathias; Li, Fengqing; Cai, Qinghua; Haase, Peter; Jähnig, Sonja C.

2015-01-01

Little work has been done on large-scale patterns of stream insect richness in China. We explored the influence of climatic and catchment-scale factors on stream insect (Ephemeroptera, Plecoptera, Trichoptera; EPT) richness across mid-latitude China. We assessed the predictive ability of climatic, catchment land cover and physical structure variables on genus richness of EPT, both individually and combined, in 80 mid-latitude Chinese streams, spanning a 3899-m altitudinal gradient. We performed analyses using boosted regression trees and explored the nature of their influence on richness patterns. The relative importance of climate, land cover, and physical factors on stream insect richness varied considerably between the three orders, and while important for Ephemeroptera and Plecoptera, latitude did not improve model fit for any of the groups. EPT richness was linked with areas comprising high forest cover, elevation and slope, large catchments and low temperatures. Ephemeroptera favoured areas with high forest cover, medium-to-large catchment sizes, high temperature seasonality, and low potential evapotranspiration. Plecoptera richness was linked with low temperature seasonality and annual mean, and high slope, elevation and warm-season rainfall. Finally, Trichoptera favoured high elevation areas, with high forest cover, and low mean annual temperature, seasonality and aridity. Our findings highlight the variable role that catchment land cover, physical properties and climatic influences have on stream insect richness. This is one of the first studies of its kind in Chinese streams, thus we set the scene for more in-depth assessments of stream insect richness across broader spatial scales in China, but stress the importance of improving data availability and consistency through time. PMID:25909190

Carbon redistribution by erosion processes in an intensively disturbed catchment

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Boix-Fayos, Carolina; Martínez-Mena, María; Pérez Cutillas, Pedro; de Vente, Joris; Barberá, Gonzalo G.; Mosch, Wouter; Navarro Cano, Jose Antonio; Gaspar, Leticia; Navas, Ana

2016-04-01

Understanding how organic carbon moves with sediments along the fluvial system is crucial to close catchment scale carbon budgets. Especially challenging is the analysis of organic carbon dynamics during fluvial transport in heterogeneous, fragile and disturbed environments with ephemeral and intense hydrological pulses, typical of Mediterranean conditions. This paper explores the catchment scale organic carbon redistribution by lateral flows in extreme Mediterranean environmental conditions from a geomorphological perspective. The study area is a catchment (Cárcavo) in SE Spain with a semiarid climate, erodible lithologies, shallow soils, and highly disturbed by agricultural terraces, land levelling, reforestations and construction of check-dams. To increase understanding of erosion induced catchment scale organic carbon redistribution, we studied the subcatchments of 8 check-dams distributed along the catchment main channel in detail. We determined 137Cs, physicochemical characteristics and organic carbon pools of soils and sediments deposited behind each check-dam, performed spatial analysis of properties of the catchment and buffer areas around check-dams, and carried out geomorphological analysis of the slope-channel connections. Soils showed very low Total Organic Carbon (TOC) values oscillating between 15.2 and 4.4 g Kg-1 for forest and agricultural soils, respectively. Sediments mobilized by erosion were poor in TOC compared to the eroded (forest) soils (6.6±0.7 g Kg-1), and the redistribution of organic carbon through the catchment, especially of the Mineral Associated Organic Carbon (MAC) pool, showed the same pattern as clay particles and 137Cs. The TOC erosion rates (0.031±0.03 Mg ha-1 y-1) were comparable to others reported for subhumid Mediterranean catchments and to those modelled worldwide for pasture land. Those lateral fluxes were equivalent to 10.4 % of the TOC stock from the topsoil at the moment of the check-dam construction and

Land use change impacts on floods at the catchment scale

NARCIS (Netherlands)

Rogger, M.; Agnoletti, M.; Alaoui, A.; Bathurst, J.C.; Bodner, G.; Borga, M.; Chaplot, Vincent; Gallart, F.; Glatzel, G.; Hall, J.; Holden, J.; Holko, L.; Horn, R.; Kiss, A.; Kohnová, S.; Leitinger, G.; Lennartz, B.; Parajka, J.; Perdigão, R.; Peth, S.; Plavcová, L.; Quinton, John N.; Robinson, Matthew R.; Salinas, J.L.; Santoro, A.; Szolgay, J.; Tron, S.; Akker, van den J.J.H.; Viglione, A.; Blöschl, G.

2017-01-01

Research gaps in understanding flood changes at the catchment scale caused by changes in forest management, agricultural practices, artificial drainage, and terracing are identified. Potential strategies in addressing these gaps are proposed, such as complex systems approaches to link processes

Stability of endoglucanases from mesophilic fungus and thermophilic bacterium in acidified polyols.

Science.gov (United States)

Chong, Barrie Fong; Harrison, Mark D; O'Hara, Ian M

2014-01-01

Recent developments in chemical pretreatments of lignocellulosic biomass using polyols as co-solvents (e.g., glycerol and ethylene glycol) at temperatures less than 100°C may allow the effective use of thermostable and non-thermostable cellulases in situ during the saccharification process. The potential of biomass saccharifying enzymes, endoglucanases (EG) from a thermophilic bacterium (Thermotoga maritima) and a mesophilic fungus (Trichoderma longibrachiatum), to retain their activity in aqueous buffer, acidified glycerol, and acidified ethylene glycol used as co-solvents at pretreatment temperatures at or below 100°C were examined. The results show that despite its origin, T. longibrachiatum EG (Tl-EG) retained 75% of its activity after exposure to 100°C for 5 min in aqueous buffer while T. maritima EG (Tm-EG) retained only 5% activity. However, at 90°C both enzymes retained over 87% of their activity. In acidified (0.1% (w/w) H2SO4) glycerol, Tl-EG retained similar activity (80%) to that obtained in glycerol alone, while Tm-EG retained only 35%. With acidified ethylene glycol under these conditions, both Tl-EG and Tm-EG retained 36% of their activity. The results therefore show that Tl-EG is more stable in both acidified glycerol and ethylene glycol than Tm-EG. A preliminary kinetic study showed that pure glycerol improved the thermal stability of Tl-EG but destabilized Tm-EG, relative to the buffer solution. The half-lives of both Tl-EG and Tm-EG are 4.5 min in acidified glycerol, indicating that the effectiveness of these enzymes under typical pretreatment times of greater than 15 min will be considerably diminished. Attempts have been made to explain the differences in the results obtained between the two enzymes. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of distributed and centralized stormwater best management practices and land cover on urban stream hydrology at the catchment scale

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Loperfido, J. V.; Noe, Gregory B.; Jarnagin, S. Taylor; Hogan, Dianna M.

2014-11-01

Urban stormwater runoff remains an important issue that causes local and regional-scale water quantity and quality issues. Stormwater best management practices (BMPs) have been widely used to mitigate runoff issues, traditionally in a centralized manner; however, problems associated with urban hydrology have remained. An emerging trend is implementation of BMPs in a distributed manner (multi-BMP treatment trains located on the landscape and integrated with urban design), but little catchment-scale performance of these systems have been reported to date. Here, stream hydrologic data (March, 2011-September, 2012) are evaluated in four catchments located in the Chesapeake Bay watershed: one utilizing distributed stormwater BMPs, two utilizing centralized stormwater BMPs, and a forested catchment serving as a reference. Among urban catchments with similar land cover, geology and BMP design standards (i.e. 100-year event), but contrasting placement of stormwater BMPs, distributed BMPs resulted in: significantly greater estimated baseflow, a higher minimum precipitation threshold for stream response and maximum discharge increases, better maximum discharge control for small precipitation events, and reduced runoff volume during an extreme (1000-year) precipitation event compared to centralized BMPs. For all catchments, greater forest land cover and less impervious cover appeared to be more important drivers than stormwater BMP spatial pattern, and caused lower total, stormflow, and baseflow runoff volume; lower maximum discharge during typical precipitation events; and lower runoff volume during an extreme precipitation event. Analysis of hydrologic field data in this study suggests that both the spatial distribution of stormwater BMPs and land cover are important for management of urban stormwater runoff. In particular, catchment-wide application of distributed BMPs improved stream hydrology compared to centralized BMPs, but not enough to fully replicate forested

Effects of distributed and centralized stormwater best management practices and land cover on urban stream hydrology at the catchment scale

Science.gov (United States)

Loperfido, John V.; Noe, Gregory B.; Jarnagin, S. Taylor; Hogan, Dianna M.

2014-01-01

Urban stormwater runoff remains an important issue that causes local and regional-scale water quantity and quality issues. Stormwater best management practices (BMPs) have been widely used to mitigate runoff issues, traditionally in a centralized manner; however, problems associated with urban hydrology have remained. An emerging trend is implementation of BMPs in a distributed manner (multi-BMP treatment trains located on the landscape and integrated with urban design), but little catchment-scale performance of these systems have been reported to date. Here, stream hydrologic data (March, 2011–September, 2012) are evaluated in four catchments located in the Chesapeake Bay watershed: one utilizing distributed stormwater BMPs, two utilizing centralized stormwater BMPs, and a forested catchment serving as a reference. Among urban catchments with similar land cover, geology and BMP design standards (i.e. 100-year event), but contrasting placement of stormwater BMPs, distributed BMPs resulted in: significantly greater estimated baseflow, a higher minimum precipitation threshold for stream response and maximum discharge increases, better maximum discharge control for small precipitation events, and reduced runoff volume during an extreme (1000-year) precipitation event compared to centralized BMPs. For all catchments, greater forest land cover and less impervious cover appeared to be more important drivers than stormwater BMP spatial pattern, and caused lower total, stormflow, and baseflow runoff volume; lower maximum discharge during typical precipitation events; and lower runoff volume during an extreme precipitation event. Analysis of hydrologic field data in this study suggests that both the spatial distribution of stormwater BMPs and land cover are important for management of urban stormwater runoff. In particular, catchment-wide application of distributed BMPs improved stream hydrology compared to centralized BMPs, but not enough to fully replicate forested

Acid-base status and changes in Swedish forest soils

International Nuclear Information System (INIS)

Karltun, Erik; Stendahl, Johan; Lundin, Lars

2003-01-01

In this paper we use data from the Swedish National Survey of Forest Soils and Vegetation (NSFSV) to evaluate the present acid-base status of forest soils to try to answer the following questions. Which role do anthropogenic and biological acidification play for the present acid-base status of the soil profile? What is the present acid-base status of Swedish forest soils and how large areas may be considered as severely acidified? Do the current tendencies in soil acid-base status correspond with the positive development in surface waters?

The Serum Metabolite Response to Diet Intervention with Probiotic Acidified Milk in Irritable Bowel Syndrome Patients Is Indistinguishable from that of Non-Probiotic Acidified Milk by 1H NMR-Based Metabonomic Analysis

Directory of Open Access Journals (Sweden)

Ulla Svensson

2010-11-01

Full Text Available The effects of a probiotic acidified milk product on the blood serum metabolite profile of patients suffering from Irritable Bowel Syndrome (IBS compared to a non-probiotic acidified milk product was investigated using 1H NMR metabonomics. For eight weeks, IBS patients consumed 0.4 L per day of a probiotic fermented milk product or non-probiotic acidified milk. Both diets resulted in elevated levels of blood serum l-lactate and 3-hydroxybutyrate. Our results showed identical effects of acidified milk consumption independent of probiotic addition. A similar result was previously obtained in a questionnaire-based evaluation of symptom relief. A specific probiotic effect is thus absent both in the patient subjective symptom evaluations and at the blood serum metabolite level. However, there was no correspondence between symptom relief and metabolite response on the patient level.

Permafrost conditions in peatlands regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export.

Science.gov (United States)

Olefeldt, David; Roulet, Nigel T

2014-10-01

Permafrost thaw in peatlands has the potential to alter catchment export of dissolved organic carbon (DOC) and thus influence downstream aquatic C cycling. Subarctic peatlands are often mosaics of different peatland types, where permafrost conditions regulate the hydrological setting of each type. We show that hydrological setting is key to observed differences in magnitude, timing, and chemical composition of DOC export between permafrost and nonpermafrost peatland types, and that these differences influence the export of DOC of larger catchments even when peatlands are minor catchment components. In many aspects, DOC export from a studied peatland permafrost plateau was similar to that of a forested upland catchment. Similarities included low annual export (2-3 g C m(-2) ) dominated by the snow melt period (~70%), and how substantial DOC export following storms required wet antecedent conditions. Conversely, nonpermafrost fens had higher DOC export (7 g C m(-2) ), resulting from sustained hydrological connectivity during summer. Chemical composition of catchment DOC export arose from the mixing of highly aromatic DOC from organic soils from permafrost plateau soil water and upland forest surface horizons with nonaromatic DOC from mineral soil groundwater, but was further modulated by fens. Increasing aromaticity from fen inflow to outlet was substantial and depended on both water residence time and water temperature. The role of fens as catchment biogeochemical hotspots was further emphasized by their capacity for sulfate retention. As a result of fen characteristics, a 4% fen cover in a mixed catchment was responsible for 34% higher DOC export, 50% higher DOC concentrations and ~10% higher DOC aromaticity at the catchment outlet during summer compared to a nonpeatland upland catchment. Expansion of fens due to thaw thus has potential to influence landscape C cycling by increasing fen capacity to act as biogeochemical hotspots, amplifying aquatic C cycling, and

Hydrologic connectivity between landscapes and streams: Transferring reach‐ and plot‐scale understanding to the catchment scale

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Jencso, Kelsey G.; McGlynn, Brian L.; Gooseff, Michael N.; Wondzell, Steven M.; Bencala, Kenneth E.; Marshall, Lucy 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.

Fifty years of watershed research on the Fernow Experimental Forest, WV: effects of forest management and air pollution on hardwood forests

Science.gov (United States)

M.B. Adams; P.J. Edwards; J.N. Kochenderfer; F. Wood

2004-01-01

In 1951, stream gaging was begun on five small headwater catchments on the Fernow Experimental Forest in West Virginia, to study the effects of forest management activities, particularly timber harvesting, on water yield and quality. Results from these watersheds, and others gaged more recently, have shown that annual water yields increase in proportion to the basal...

Post-Exercise Muscle Protein Synthesis in Rats after Ingestion of Acidified Bovine Milk Compared with Skim Milk.

Science.gov (United States)

Nakayama, Kyosuke; Kanda, Atsushi; Tagawa, Ryoichi; Sanbongi, Chiaki; Ikegami, Shuji; Itoh, Hiroyuki

2017-09-27

Bovine milk proteins have a low absorption rate due to gastric acid-induced coagulation. Acidified milk remains liquid under acidic conditions; therefore, the absorption rate of its protein may differ from that of untreated milk. To investigate how this would affect muscle protein synthesis (MPS), we compared MPS after ingestion of acidified versus skim milk in rats. Male Sprague-Dawley rats swam for 2 h and were immediately administered acidified or skim milk, then euthanized at 30, 60, 90, and 120 min afterwards. Triceps muscle samples were excised for assessing fractional synthetic rate (FSR), plasma components, intramuscular free amino acids and mTOR signaling. The FSR in the acidified milk group was significantly higher than in the skim milk group throughout the post-ingestive period. Plasma essential amino acids, leucine, and insulin levels were significantly increased in the acidified milk group at 30 min after administration compared to the skim milk group. In addition, acidified milk ingestion was associated with greater phosphorylation of protein kinase B (Akt) and ribosomal protein S6 kinase (S6K1), and sustained phosphorylation of 4E-binding protein 1 (4E-BP1). These results indicate that compared with untreated milk, acidified milk ingestion is associated with greater stimulation of post-exercise MPS.

Post-Exercise Muscle Protein Synthesis in Rats after Ingestion of Acidified Bovine Milk Compared with Skim Milk

Directory of Open Access Journals (Sweden)

Kyosuke Nakayama

2017-09-01

Full Text Available Bovine milk proteins have a low absorption rate due to gastric acid-induced coagulation. Acidified milk remains liquid under acidic conditions; therefore, the absorption rate of its protein may differ from that of untreated milk. To investigate how this would affect muscle protein synthesis (MPS, we compared MPS after ingestion of acidified versus skim milk in rats. Male Sprague-Dawley rats swam for 2 h and were immediately administered acidified or skim milk, then euthanized at 30, 60, 90, and 120 min afterwards. Triceps muscle samples were excised for assessing fractional synthetic rate (FSR, plasma components, intramuscular free amino acids and mTOR signaling. The FSR in the acidified milk group was significantly higher than in the skim milk group throughout the post-ingestive period. Plasma essential amino acids, leucine, and insulin levels were significantly increased in the acidified milk group at 30 min after administration compared to the skim milk group. In addition, acidified milk ingestion was associated with greater phosphorylation of protein kinase B (Akt and ribosomal protein S6 kinase (S6K1, and sustained phosphorylation of 4E-binding protein 1 (4E-BP1. These results indicate that compared with untreated milk, acidified milk ingestion is associated with greater stimulation of post-exercise MPS.

Influence of acidified drinking water on growth performance and gastrointestinal function of broilers.

Science.gov (United States)

Hamid, H; Shi, H Q; Ma, G Y; Fan, Y; Li, W X; Zhao, L H; Zhang, J Y; Ji, C; Ma, Q G

2018-06-01

The ban on the use of antibiotic feed additives as growth promoters compelled the researchers for exploring the future utility of other alternatives. This experiment was designed to evaluate the effect of acidified drinking water on growth performance, gastrointestinal pH, digestive enzymes, intestinal histomorphology, and cecum microbial counting of the broiler chicken. A total of 540 one-day-old male broilers (Arbor Acre) were randomly assigned to 5 treatments, with 6 replicates of 18 chicks per replicate. Broilers received diets and water as follows: NC (negative control, basal diet, normal water), PC (positive control, basal diet + 8 ppm colistin sulfate + 8 ppm enduracidin, normal water), A1 (basal diet, continuous supply of acidified water during whole experiment period), A2 (basal diet, intermittent acidification of water during 0 to 14 d, 22 to 28 d, and 36 to 42 d), and A3 [basal diet, intermittent acidification of water (24 h/d from 0 to 14 d and from 10:00 am to 4:00 pm on d 15 to 42)]. During the entire period, the acidified groups (A1, A2, and A3) and PC group showed improve on weight gain, average daily gain and feed conversion ratio compared to NC group (P < 0.05). The pH in crop, proventriculus and ileum at 43 d declined by 0.04, 1.03, 1.23; 0.55, 0.69, 0.70; and 0.63, 0.74, 1.21 in A1, A2, and A3 group, respectively. There was a significant decline of lipase activity in the PC and acidified groups compared to NC group. The A2 group had higher villus height in jejunum than NC group. The PC and acidified groups reduced (P < 0.05) the total aerobic bacteria count of cecum when contrasted to NC group. Therefore, we conclude that acidified drinking water can improve growth performance, compensate for gastric acidity, and control pathogenic bacteria in broilers and may be considered as a potential alternative to improve production parameters. Discontinuous supply of acidified water had the same or even better influence on broilers compared to

[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.

Runoff changes have a land cover specific effect on the seasonal fluxes of terminal electron acceptors in the boreal catchments.

Science.gov (United States)

Mattsson, Tuija; Lehtoranta, Jouni; Ekholm, Petri; Palviainen, Marjo; Kortelainen, Pirkko

2017-12-01

Climate change influences the volume and seasonal distribution of runoff in the northern regions. Here, we study how the seasonal variation in the runoff affects the concentrations and export of terminal electron acceptors (i.e. TEAs: NO 3 , Mn, Fe and SO 4 ) in different boreal land-cover classes. Also, we make a prediction how the anticipated climate change induced increase in runoff will alter the export of TEAs in boreal catchments. Our results show that there is a strong positive relationship between runoff and the concentration of NO 3 -N, Mn and Fe in agricultural catchments. In peaty catchments, the relationship is poorer and the concentrations of TEAs tend to decrease with increasing runoff. In forested catchments, the correlation between runoff and TEA concentrations was weak. In most catchments, the concentrations of SO 4 decrease with an increase in runoff regardless of the land cover or season. The wet years export much higher amounts of TEAs than the dry years. In southern agricultural catchments, the wet years increased the TEA export for both spring (January-May) and autumn (September-December) periods, while in the peaty and forested catchments in eastern and northern Finland the export only increased in the autumn. Our predictions for the year 2099 indicate that the export of TEAs will increase especially from agricultural but also from forested catchments. Additionally, the predictions show an increase in the export of Fe and SO 4 for all the catchments for the autumn. Thus, the climate induced change in the runoff regime is likely to alter the exported amount of TEAs and the timing of the export downstream. The changes in the amounts and timing in the export of TEAs have a potential to modify the mineralization pathways in the receiving water bodies, with feedbacks in the cycling of C, nutrients and metals in aquatic ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

Use of multivitamin, acidifier and Azolla in the diet of broiler chickens.

Science.gov (United States)

Islam, M A; Nishibori, M

2017-05-01

The experiments were carried out to measure the effect of multivitamin, acidifier and Azolla on growth performance, profitability and lipid profiles of blood of broiler chickens to produce safe and cost effective broilers. In experiment 1, 240 day-old Cobb-500 broiler chicks were fed diets; D 1 (control), D 2 (D 1 with 1 mL multivitamin/liter water), D 3 (D 1 with 1 mL acidifier/liter water), D 4 (D 1 with 1 mL multivitamin and 2 mL acidifier/liter water) having 3 replications in each, and 20 chicks/replication. In experiment 2, 150 day-old Cobb-500 broiler chicks were fed diets; T 1 (control), T 2 (5% Azolla in the diet), T 3 (7% Azolla in the diet) and T 4 (T 1 with 1 mL multivitamin and 1 mL acidifier/liter water) having 3 replications in each, and 20 chicks/replication in control, and 10 chicks/replication in the remaining dietary treatment groups for 35 days. In experiment 1, the highest live weight was observed in D 4 (p0.05). The lowest feed conversion ratio (FCR) (p0.05). However, evidently but not significantly, the highest net profit was obtained in D 2 followed by D 4 , D 1 , and D 3 , respectively. In experiment 2, the highest live weight (p0.05). In conclusion, Azolla and acidifier reduced lipid profiles of broiler chickens. Considering net profit and lipid profiles, 5% Azolla may be the suitable dietary group for producing safe and profitable broilers. However, more studies are needed to confirm this study prior to suggesting using Azolla in the poultry industry.

Impacts of the Conversion of Forest to Arable Land and Long Term Agriculture Practices on the Water Pathways in Southern Brazil

Science.gov (United States)

Robinet, J.; Minella, J. P. G.; Schlesner, A.; Lücke, A.; Ameijeiras-Marino, Y.; Opfergelt, S.; Vanderborght, J.; Gerard, G.

2017-12-01

Changes in runoff pathways affect many environmental processes. Land use change (LUC), and more specifically forest conversion to arable land, is one of the controls of water fluxes at the hillslope or catchment scale. Still, the long term effects of forest conversion and agricultural activities in (sub-) tropical environments have been relatively understudied. Our objective was therefore to study the impact of deforestation and land degradation through agriculture on runoff pathways. We selected two small catchments with contrasting land use (agriculture vs. natural forest) in a subtropical region in the south of Brazil. Stream-, pore-, subsurface- and rainwater were monitored, sampled and analyzed for Dissolve Silicon concentration (DSi) and δ18O isotopic signature. Both forested and agricultural catchments were highly responsive to rainfall event and only 2 runoff components contributed to the stream discharge were identified: baseflow and peak flow components. The δ18O peak flow signal in the agricultural catchment was closely related to the δ18O rainfall signal. In the forested catchment, the δ18O peak flow signal was similar to a seasonally averaged signal. This suggested that most peak flow was derived from current rainfall events in the agricultural catchment, while being derived from a mixed reservoir in the forested one. The DSi of the peak flow was low in both catchments. Hence, the mixing in the forested catchment cannot have taken place in the soil matrix as the soil pore water contained high DSi concentrations. Instead, the mixing must have taken place in a reservoir with a relatively short residence time and isolated, to some extent, from the soil matrix. The dense channel network left by decayed roots in the forest soil above a clay-rich water-impeding B horizon is the most likely candidate and this was confirmed by visual observations. Contributions of other, deeper reservoirs are unlikely given the quick response time of the catchment

Impacts of fire on forest age and runoff in mountain ash forests

Science.gov (United States)

Wood, S.A.; Beringer, J.; Hutley, L.B.; McGuire, A.D.; Van Dijk, A.; Kilinc, M.

2008-01-01

Runoff from mountain ash (Eucalyptus regnans F.Muell.) forested catchments has been shown to decline significantly in the few decades following fire - returning to pre-fire levels in the following centuries - owing to changes in ecosystem water use with stand age in a relationship known as Kuczera's model. We examined this relationship between catchment runoff and stand age by measuring whole-ecosystem exchanges of water using an eddy covariance system measuring forest evapotranspiration (ET) combined with sap-flow measurements of tree water use, with measurements made across a chronosequence of three sites (24, 80 and 296 years since fire). At the 296-year old site eddy covariance systems were installed above the E. regnans overstorey and above the distinct rainforest understorey. Contrary to predictions from the Kuczera curve, we found that measurements of whole-forest ET decreased by far less across stand age between 24 and 296 years. Although the overstorey tree water use declined by 1.8 mm day-1 with increasing forest age (an annual decrease of 657 mm) the understorey ET contributed between 1.2 and 1.5 mm day-1, 45% of the total ET (3 mm day-1) at the old growth forest. ?? CSIRO 2008.

Changing forest water yields in response to climate warming: results from long-term experimental watershed sites across North America

Science.gov (United States)

Creed, Irena F; Spargo, Adam T; Jones, Julia A; Buttle, Jim M; Adams, Mary B; Beall, Fred D; Booth, Eric G; Campbell, John L; Clow, Dave; Elder, Kelly; Green, Mark B; Grimm, Nancy B; Miniat, Chelcy; Ramlal, Patricia; Saha, Amartya; Sebestyen, Stephen; Spittlehouse, Dave; Sterling, Shannon; Williams, Mark W; Winkler, Rita; Yao, Huaxia

2014-01-01

Climate warming is projected to affect forest water yields but the effects are expected to vary. We investigated how forest type and age affect water yield resilience to climate warming. To answer this question, we examined the variability in historical water yields at long-term experimental catchments across Canada and the United States over 5-year cool and warm periods. Using the theoretical framework of the Budyko curve, we calculated the effects of climate warming on the annual partitioning of precipitation (P) into evapotranspiration (ET) and water yield. Deviation (d) was defined as a catchment's change in actual ET divided by P [AET/P; evaporative index (EI)] coincident with a shift from a cool to a warm period – a positive d indicates an upward shift in EI and smaller than expected water yields, and a negative d indicates a downward shift in EI and larger than expected water yields. Elasticity was defined as the ratio of interannual variation in potential ET divided by P (PET/P; dryness index) to interannual variation in the EI – high elasticity indicates low d despite large range in drying index (i.e., resilient water yields), low elasticity indicates high d despite small range in drying index (i.e., nonresilient water yields). Although the data needed to fully evaluate ecosystems based on these metrics are limited, we were able to identify some characteristics of response among forest types. Alpine sites showed the greatest sensitivity to climate warming with any warming leading to increased water yields. Conifer forests included catchments with lowest elasticity and stable to larger water yields. Deciduous forests included catchments with intermediate elasticity and stable to smaller water yields. Mixed coniferous/deciduous forests included catchments with highest elasticity and stable water yields. Forest type appeared to influence the resilience of catchment water yields to climate warming, with conifer and deciduous catchments more susceptible to

Accounting for Ecohydrologic Separation Alters Interpreted Catchment Hydrology

Science.gov (United States)

Cain, M. R.; Ward, A. S.; Hrachowitz, M.

2017-12-01

Recent studies have demonstrated that in in some catchments, compartmentalized pools of water supply either plant transpiration (poorly mobile water) or streamflow and groundwater (highly mobile water), a phenomenon referred to as ecohydrologic separation. Although the literature has acknowledged that omission of ecohydrologic separation in hydrological models may influence estimates of residence times of water and solutes, no study has investigated how and when this compartmentalization might alter interpretations of fluxes and storages within a catchment. In this study, we develop two hydrochemical lumped rainfall-runoff models, one which incorporates ecohydrologic separation and one which does not for a watershed at the H.J. Andrews Experimental Forest (Oregon, USA), the study site where ecohydrologic separation was first observed. The models are calibrated against stream discharge, as well as stream chloride concentration. The objectives of this study are (1) to compare calibrated parameters and identifiability across models, (2) to determine how and when compartmentalization of water in the vadose zone might alter interpretations of fluxes and stores within the catchment, and (3) to identify how and when these changes alter residence times. Preliminary results suggest that compartmentalization of the vadose zone alters interpretations of fluxes and storages in the catchment and improves our ability to simulate solute transport.

Reconstructing pre-acidification pH for an acidified Scottish loch: A comparison of palaeolimnological and modelling approaches

International Nuclear Information System (INIS)

Battarbee, R.W.; Monteith, D.T.; Juggins, S.; Evans, C.D.; Jenkins, A.; Simpson, G.L.

2005-01-01

We reconstruct the pre-acidification pH of the Round Loch of Glenhead for 1800 AD using three diatom-pH transfer functions and a diatom-cladocera modern analogue technique (MAT), and compare these palaeo-data with hindcast data for the loch using the dynamic catchment acidification model MAGIC. We assess the accuracy of the transfer functions by comparing pH inferences from contemporary sediment and sediment trap diatom samples from the lake with measured pH from the UK Acid Waters Monitoring Network. The results from the transfer functions estimate the pH in 1800 to have been between 5.5. and 5.7, the MAT approach estimates pH at 5.8 and the MAGIC hindcast (for 1850) is pH 6.1. Whilst we have no independent method of assessing which of these values is most accurate, the disagreement between the two approaches indicates that further work is needed to resolve the discrepancies. - Methods of reconstructing pre-acidification pH for an acidified Scottish loch compared

The Serum Metabolite Response to Diet Intervention with Probiotic Acidified Milk in Irritable Bowel Syndrome Patients is Indistinguishable from that of Non-Probiotic Acidified Milk by ¹H NMR-Based Metabonomic Analysis

DEFF Research Database (Denmark)

Pedersen, Simon M M; Nielsen, Niels Chr; Andersen, Henrik J

2010-01-01

of a probiotic fermented milk product or non-probiotic acidified milk. Both diets resulted in elevated levels of blood serum L-lactate and 3-hydroxybutyrate. Our results showed identical effects of acidified milk consumption independent of probiotic addition. A similar result was previously obtained...

Administration of acidified drinking water to finishing pigs in order to prevent Salmonella infections

NARCIS (Netherlands)

Wolf, van der P.J.; Schie, van F.W.; Elbers, A.R.W.; Engel, B.; Heijden, van der H.; Hunneman, W.A.; Tielen, M.J.M.

2001-01-01

The aim of the study was to test whether acidified drinking water, with two millilitres of an acid mixture per litre, was able to reduce the number of Salmonella infections in finishing pig herds. In each compartment, half of the pens were supplied with acidified water and the other pens served as

Use of multivitamin, acidifier and Azolla in the diet of broiler chickens

Directory of Open Access Journals (Sweden)

M. A. Islam

2017-05-01

Full Text Available Objective The experiments were carried out to measure the effect of multivitamin, acidifier and Azolla on growth performance, profitability and lipid profiles of blood of broiler chickens to produce safe and cost effective broilers. Methods In experiment 1, 240 day-old Cobb-500 broiler chicks were fed diets; D1 (control, D2 (D1 with 1 mL multivitamin/liter water, D3 (D1 with 1 mL acidifier/liter water, D4 (D1 with 1 mL multivitamin and 2 mL acidifier/liter water having 3 replications in each, and 20 chicks/replication. In experiment 2, 150 day-old Cobb-500 broiler chicks were fed diets; T1 (control, T2 (5% Azolla in the diet, T3 (7% Azolla in the diet and T4 (T1 with 1 mL multivitamin and 1 mL acidifier/liter water having 3 replications in each, and 20 chicks/replication in control, and 10 chicks/replication in the remaining dietary treatment groups for 35 days. Results In experiment 1, the highest live weight was observed in D4 (p0.05. The lowest feed conversion ratio (FCR (p0.05. However, evidently but not significantly, the highest net profit was obtained in D2 followed by D4, D1, and D3, respectively. In experiment 2, the highest live weight (p0.05. Conclusion In conclusion, Azolla and acidifier reduced lipid profiles of broiler chickens. Considering net profit and lipid profiles, 5% Azolla may be the suitable dietary group for producing safe and profitable broilers. However, more studies are needed to confirm this study prior to suggesting using Azolla in the poultry industry.

Nebulization of the acidified sodium nitrite formulation attenuates acute hypoxic pulmonary vasoconstriction

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Surber Mark W

2010-06-01

Full Text Available Abstract Background Generalized hypoxic pulmonary vasoconstriction (HPV occurring during exposure to hypoxia is a detrimental process resulting in an increase in lung vascular resistance. Nebulization of sodium nitrite has been shown to inhibit HPV. The aim of this project was to investigate and compare the effects of nebulization of nitrite and different formulations of acidified sodium nitrite on acute HPV. Methods Ex vivo isolated rabbit lungs perfused with erythrocytes in Krebs-Henseleit buffer (adjusted to 10% hematocrit and in vivo anesthetized catheterized rabbits were challenged with periods of hypoxic ventilation alternating with periods of normoxic ventilation. After baseline hypoxic challenges, vehicle, sodium nitrite or acidified sodium nitrite was delivered via nebulization. In the ex vivo model, pulmonary arterial pressure and nitric oxide concentrations in exhaled gas were monitored. Nitrite and nitrite/nitrate were measured in samples of perfusion buffer. Pulmonary arterial pressure, systemic arterial pressure, cardiac output and blood gases were monitored in the in vivo model. Results In the ex vivo model, nitrite nebulization attenuated HPV and increased nitric oxide concentrations in exhaled gas and nitrite concentrations in the perfusate. The acidified forms of sodium nitrite induced higher levels of nitric oxide in exhaled gas and had longer vasodilating effects compared to nitrite alone. All nitrite formulations increased concentrations of circulating nitrite to the same degree. In the in vivo model, inhaled nitrite inhibited HPV, while pulmonary arterial pressure, cardiac output and blood gases were not affected. All nitrite formulations had similar potency to inhibit HPV. The tested concentration of appeared tolerable. Conclusion Nitrite alone and in acidified forms effectively and similarly attenuates HPV. However, acidified nitrite formulations induce a more pronounced increase in nitric oxide exhalation.

Use of a 137Cs re-sampling technique to investigate temporal changes in soil erosion and sediment mobilisation for a small forested catchment in southern Italy

International Nuclear Information System (INIS)

Porto, Paolo; Walling, Des E.; Alewell, Christine; Callegari, Giovanni; Mabit, Lionel; Mallimo, Nicola; Meusburger, Katrin; Zehringer, Markus

2014-01-01

Soil erosion and both its on-site and off-site impacts are increasingly seen as a serious environmental problem across the world. The need for an improved evidence base on soil loss and soil redistribution rates has directed attention to the use of fallout radionuclides, and particularly 137 Cs, for documenting soil redistribution rates. This approach possesses important advantages over more traditional means of documenting soil erosion and soil redistribution. However, one key limitation of the approach is the time-averaged or lumped nature of the estimated erosion rates. In nearly all cases, these will relate to the period extending from the main period of bomb fallout to the time of sampling. Increasing concern for the impact of global change, particularly that related to changing land use and climate change, has frequently directed attention to the need to document changes in soil redistribution rates within this period. Re-sampling techniques, which should be distinguished from repeat-sampling techniques, have the potential to meet this requirement. As an example, the use of a re-sampling technique to derive estimates of the mean annual net soil loss from a small (1.38 ha) forested catchment in southern Italy is reported. The catchment was originally sampled in 1998 and samples were collected from points very close to the original sampling points again in 2013. This made it possible to compare the estimate of mean annual erosion for the period 1954–1998 with that for the period 1999–2013. The availability of measurements of sediment yield from the catchment for parts of the overall period made it possible to compare the results provided by the 137 Cs re-sampling study with the estimates of sediment yield for the same periods. In order to compare the estimates of soil loss and sediment yield for the two different periods, it was necessary to establish the uncertainty associated with the individual estimates. In the absence of a generally accepted procedure

Defining reference conditions for acidified waters using a modern analogue approach

International Nuclear Information System (INIS)

Simpson, Gavin L.; Shilland, Ewan M.; Winterbottom, Julie M.; Keay, Janey

2005-01-01

Analogue matching is a palaeolimnological technique that aims to find matches for fossil sediment samples from a set of modern surface sediment samples. Modern analogues were identified that closely matched the pre-disturbance conditions of eight of the UK Acid Waters Monitoring Network (AWMN) lakes using diatom- and cladoceran-based analogue matching. These analogue sites were assessed in terms of hydrochemistry, aquatic macrophytes and macro-invertebrates as to their suitability for defining wider hydrochemical and biological reference conditions for acidified sites within the AWMN. The analogues identified for individual AWMN sites show a close degree of similarity in terms of their hydrochemical characteristics, aquatic macrophytes and, to a lesser extent, macro-invertebrate fauna. The reference conditions of acidified AWMN sites are inferred to be less acidic than today and to support a wider range of acid-sensitive aquatic macrophyte and macro-invertebrate taxa than that recorded in the AWMN lakes over the period of monitoring since 1988. - The use of a palaeolimnological technique to identify modern ecological reference analogues for acidified lakes is demonstrated

Source Areas of Water and Nitrate in a Peatland Catchment, Minnesota, USA

Science.gov (United States)

Sebestyen, S. D.

2017-12-01

In nitrogen polluted forests, stream nitrate concentrations increase and some unprocessed atmospheric nitrate may be transported to streams during stormflow events. This understanding has emerged from forests with upland mineral soils. In contrast, catchments with northern peatlands may have both upland soils and lowlands with deep organic soils, each with unique effects on nitrate transport and processing. While annual budgets show nitrate yields to be relatively lower from peatland than upland-dominated catchments, little is known about particular runoff events when stream nitrate concentrations have been higher (despite long periods with little or no nitrate in outlet streams) or the reasons why. I used site knowledge and expansive/extensive monitoring at the Marcell Experimental Forest in Minnesota, along with a targeted 2-year study to determine landscape areas, water sources, and nitrate sources that affected stream nitrate variation in a peatland catchment. I combined streamflow, upland runoff, snow amount, and frost depth data from long-term monitoring with nitrate concentration, yield, and isotopic data to show that up to 65% of stream nitrate during snowmelt of 2009 and 2010 was unprocessed atmospheric nitrate. Up to 46% of subsurface runoff from upland soils during 2009 was unprocessed atmospheric nitrate, which shows the uplands to be a stream nitrate source during 2009, but not during 2010 when upland runoff concentrations were below the detection limit. Differences are attributable to variations in water and nitrate sources. Little snow (a nitrate source), less upland runoff relative to peatland runoff, and deeper soil frost in the peatland caused a relatively larger input of nitrate from the uplands to the stream during 2009 and the peatland to the stream during 2010. Despite the near-absence of stream nitrate during much of rest of the year, these findings show an important time when nitrate transport affected downstream aquatic ecosystems, reasons

Effectiveness of hydrological forest restoration projects on soil erosion control in Mediterranean catchment

International Nuclear Information System (INIS)

Castillo, V. M.; Boix Fayos, C.; Vente, J. de; Martinez-Mena, M.; Barbera, G. G.

2009-01-01

Extensive land use changes have occurred in many Mediterranean catchments as a result of reforestation and the abandonment of agricultural activities. Besides this, the establishment of check-dams has been promoted to reduce soil erosion and sediment transport. In this study a combination of field work, mapping and modelling was used to test influence of land use scenarios with and without sediment control structures on sediment yield at catchment scale. Model simulation shows that in a scenario without check-dams, the land used changes between 1956 and 1997 caused a progressive decrease in sediment yield of 54%. In a scenario without land use changes but with check-dams, about 77% of the sediment yield was retained behind the dams. Both land use changes and check-dams are effective measures decreasing sediment yield in catchment, however they act at very different temporal scales. (Author) 5 refs.

Effects of silicate weathering on water chemistry in forested, upland, felsic terrane of the USA

International Nuclear Information System (INIS)

Stauffer, R.E.; Wittchen, B.D.

1991-01-01

The authors use data from the US EPA National Surface Water Survey (NSWS), the USGS Bench-Mark Station monitoring program, and the National Acid Deposition Program (NADP) to evaluate the role of weathering in supplying base cations to surface waters in forested, upland, felsic terrane of the northeastern, northcentral, and northwestern (Idaho batholith) US. Multivariate regression reveals differential effects of discharge on individual base cations and silica, but no secular trend in the Ca/Na denudation rate over 24 yr (1965-1988) for the Wild River catchment in the White Mountains. Because the turn-over time for Na in the soil-exchange complex is only ca. 1.5 yr, the long-term behavior of the ratios Ca/Na and Si/Na in waters leaving this catchment indicates that weathering is compensating for base cation export. In every subregion, Ca and Mg concentrations in lakes are statistically linked to nonmarine Na, but the median Ca/Na ratio is greater than the ratio in local plagioclase. The authors attribute this inequality to nonstoichiometric weathering of calcium in juvenile (formerly glaciated) terrane, not to leaching of exchangeable cations by So 4 because intraregional and cross-regional statistical analysis reveals no effect of atmospherically derived sulfate ion. The median base cation denudation rates (meq m -2 yr -1 ) for these American lake regions are: Maine granites (108); western Adirondack felsic gneiss (85); Vermilion batholith (42); Idaho batholith (52). The regional rates are high enough to compensate for present wet deposition of acidifying anions except in some vulnerable lake watersheds in the western Adirondacks

Flash Flood Type Identification within Catchments in Beijing Mountainous Area

Science.gov (United States)

Nan, W.

2017-12-01

Flash flood is a common type of disaster in mountainous area, Flash flood with the feature of large flow rate, strong flushing force, destructive power, has periodically caused loss to life and destruction to infrastructure in mountainous area. Beijing as China's political, economic and cultural center, the disaster prevention and control work in Beijing mountainous area has always been concerned widely. According to the transport mechanism, sediment concentration and density, the flash flood type identification within catchment can provide basis for making the hazards prevention and mitigation policy. Taking Beijing as the study area, this paper extracted parameters related to catchment morphological and topography features respectively. By using Bayes discriminant, Logistic regression and Random forest, the catchments in Beijing mountainous area were divided into water floods process, fluvial sediment transport process and debris flows process. The results found that Logistic regression analysis showed the highest accuracy, with the overall accuracy of 88.2%. Bayes discriminant and Random forest had poor prediction effects. This study confirmed the ability of morphological and topography features to identify flash flood process. The circularity ratio, elongation ratio and roughness index can be used to explain the flash flood types effectively, and the Melton ratio and elevation relief ratio also did a good job during the identification, whereas the drainage density seemed not to be an issue at this level of detail. Based on the analysis of spatial patterns of flash flood types, fluvial sediment transport process and debris flow process were the dominant hazards, while the pure water flood process was much less. The catchments dominated by fluvial sediment transport process were mainly distributed in the Yan Mountain region, where the fault belts were relatively dense. The debris flow process prone to occur in the Taihang Mountain region thanks to the abundant

Soil Loss Vulnerability in an Agricultural Catchment in the Atlantic Forest Biome in Southern Brazil

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Rafael Gotardo

2016-11-01

Full Text Available This study estimates soil loss vulnerability using field samples and spatial data in a 30 km² area in the Atlantic forest biome in southern Brazil. The anthropogenic part of the landscape consists mainly of small agricultural properties. Soil loss vulnerability was calculated using adaptations of the universal soil loss equation. The results were compared to sediment data collected during field surveys. Spatial analysis was performed using a geographical information system (GIS and fine resolution data (1 m. Both field and spatial analyses produced similar results, 5.390 tons of soil loss per year using field data and 5.691 tons per year using GIS. Using soil loss and sediment data related to the Concordia River, we estimate that of all the exported sediment 25% of the lost soil reaches the river. These data are an effective source of information for municipal administrators of the region, which consists of small agricultural catchments (dominated by small properties that comprise the regional economy. A thematic map was used to determine sub-drainage priority as information for public managers.

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.

Contribution of atmospheric nitrogen deposition to diffuse pollution in a typical hilly red soil catchment in southern China.

Science.gov (United States)

Shen, Jianlin; Liu, Jieyun; Li, Yong; Li, Yuyuan; Wang, Yi; Liu, Xuejun; Wu, Jinshui

2014-09-01

Atmospheric nitrogen (N) deposition is currently high and meanwhile diffuse N pollution is also serious in China. The correlation between N deposition and riverine N export and the contribution of N deposition to riverine N export were investigated in a typical hilly red soil catchment in southern China over a two-year period. N deposition was as high as 26.1 to 55.8kgN/(ha·yr) across different land uses in the studied catchment, while the riverine N exports ranged from 7.2 to 9.6kgN/(ha·yr) in the forest sub-catchment and 27.4 to 30.3kgN/(ha·yr) in the agricultural sub-catchment. The correlations between both wet N deposition and riverine N export and precipitation were highly positive, and so were the correlations between NH4(+)-N or NO3(-)-N wet deposition and riverine NH4(+)-N or NO3(-)-N exports except for NH4(+)-N in the agricultural sub-catchment, indicating that N deposition contributed to riverine N export. The monthly export coefficients of atmospheric deposited N from land to river in the forest sub-catchment (with a mean of 14%) presented a significant positive correlation with precipitation, while the monthly contributions of atmospheric deposition to riverine N export (with a mean of 18.7% in the agricultural sub-catchment and a mean of 21.0% in the whole catchment) were significantly and negatively correlated with precipitation. The relatively high contribution of N deposition to diffuse N pollution in the catchment suggests that efforts should be done to control anthropogenic reactive N emissions to the atmosphere in hilly red soil regions in southern China. Copyright © 2014. Published by Elsevier B.V.

Quantifying sediment source contributions in coastal catchments impacted by the Fukushima nuclear accident with carbon and nitrogen elemental concentrations and stable isotope ratios

Science.gov (United States)

Laceby, J. Patrick; Huon Huon, Sylvain; Onda, Yuichi; Evrard, Olivier

2016-04-01

The Fukushima Dai-ichi Nuclear Power Plant accidental release of radioactive contaminants resulted in the significant fallout of radiocesium over several coastal catchments in the Fukushima Prefecture. Radiocesium, considered to be the greatest risk to the short and long term health of the local community, is rapidly bound to fine soil particles and thus is mobilized and transported during soil erosion and runoff processes. As there has been a broad-scale decontamination of rice paddy fields and rural residential areas in the contaminated region, one important long term question is whether there is, or may be, a downstream transfer of radiocesium from forests that covered over 65% of the most contaminated region. Accordingly, carbon and nitrogen elemental concentrations and stable isotope ratios are used to determine the relative contributions of forests and rice paddies to transported sediment in three contaminated coastal catchments. Samples were taken from the three main identified sources: cultivated soils (rice paddies and fields, n=30), forest soils (n=45), and subsoils (channel bank and decontaminated soils, n = 25). Lag deposit sediment samples were obtained from five sampling campaigns that targeted the main hydrological events from October 2011 to October 2014. In total, 86 samples of deposited sediment were analyzed for particulate organic matter elemental concentrations and isotope ratios, 24 from the Mano catchment, 44 from the Niida catchment, and 18 from the Ota catchment. Mann-Whitney U-tests were used to examine the source discrimination potential of this tracing suite and select the appropriate tracers for modelling. The discriminant tracers were modelled with a concentration-dependent distribution mixing model. Preliminary results indicate that cultivated sources (predominantly rice paddies) contribute disproportionately more sediment per unit area than forested regions in these contaminated catchments. Future research will examine if there are

Sediment dynamics during the rainy season in tropical highland catchments of central Mexico using fallout radionuclides

International Nuclear Information System (INIS)

Evrard, Olivier; Ayrault, Sophie; Lefevre, Irene; Bonte, Philippe; Nemery, Julien; Gratiot, Nicolas; Duvert, Clement; Prat, Christian; Esteves, Michel; Poulenard, Jerome

2010-01-01

Tropical regions are affected by intense soil erosion associated with deforestation, overgrazing, and cropping intensification. This land degradation leads to important on-site (e.g., decrease in soil fertility) and off-site (e.g., reservoir siltation and water pollution) impacts. This study determined the mean soil particle and sediment residence times in soils and rivers of three sub-catchments (3-12 km 2 ) with contrasted land uses (i.e., cropland, forests, and rangelands) draining to a reservoir located in highlands of the trans-volcanic Mexican belt. Calculations were based on rainfall amount and river discharges as well as on fallout radionuclide measurements (Be-7, Cs-137, and Pb-210) conducted on rainfall precipitated samples, soil sampled in the catchments, and suspended sediment collected by automatic samplers in the river during most storms recorded throughout the 2009 rainy season. Calculations using a radionuclide two-box balance model showed that the mean residence time of particles in soils ranged between 5000 ± 1500 and 23, 300 ± 7000 years. In contrast, sediment residence time in rivers was much shorter, fluctuating between 50 ± 30 and 200 ± 70 days. The shortest mean residence times were measured in a hilly catchment dominated by cropland and rangelands, whereas they were the longest in an undulating catchment dominated by forests and cropland. Calculation of the Be-7/excess-Pb-210 in both rainfall and sediment allowed gaining insight on sediment dynamics throughout the rainy season. The first heavy storms of the year exported the bulk of the sediment stock accumulated in the river channel during the previous year. Then, during the rainy season, the two steeper catchments dominated by cropland and rangelands reacted strongly to rainfall. Sediment was indeed eroded and exported from both catchments during single heavy storms on several occasions in 2009. In contrast, the agro-forested catchment with gentler slopes exported sediment at a

Can the eastern red-backed salamander (Plethodon cinereus) persist in an acidified landscape?

Science.gov (United States)

Bondi, Cheryl A; Beier, Colin M.; Ducey, Peter K; Lawrence, Gregory B.; Bailey, Scott W.

2016-01-01

Hardwood forests of eastern North America have experienced decades of acidic deposition, leading to soil acidification where base cation supply was insufficient to neutralize acid inputs. Negative impacts of soil acidity on amphibians include disrupted embryonic development, lower growth rates, and habitat loss. However, some amphibians exhibit intraspecific variation in acid tolerance, suggesting the potential for local adaptation in areas where soils are naturally acidic. The eastern red-backed salamander (Plethodon cinereus) is a highly abundant top predator of the northern hardwood forest floor. Early research found that P. cinereus was sensitive to acidic soils, avoiding substrates with pH habitats. However, recent studies have documented P. cinereus populations in lower pH conditions than previously observed, suggesting some populations may persist in acidic conditions. Here, we evaluated relationships between organic horizon soil pH and P. cinereus abundance, adult health (body size and condition), and microhabitat selection, based on surveys of 34 hardwood forests in northeastern United States that encompass a regional soil pH gradient. We found no associations between soil pH and P. cinereus abundance or health, and observed that this salamander used substrates with pH similar to that available, suggesting that pH does not mediate their fine-scale distributions. The strongest negative predictor of P. cinereus abundance was the presence of dusky salamanders (Desmognathus spp.), which were most abundant in the western Adirondacks. Our results indicate that P. cinereus occupies a wider range of soil pH than has been previously thought, which has implications for their functional role in forest food webs and nutrient cycles in acid-impaired ecosystems. Tolerance of P. cinereus for more acidic habitats, including anthropogenically acidified forests, may be due to local adaptation in reproductively isolated populations and/or generalist

Mapping of hydropedologic spatial patterns in a steep headwater catchment

Science.gov (United States)

Cody P. Gillin; Scott W. Bailey; Kevin J. McGuire; John P. Gannon

2015-01-01

A hydropedologic approach can be used to describe soil units affected by distinct hydrologic regimes. We used field observations of soil morphology and geospatial information technology to map the distribution of five hydropedologic soil units across a 42-ha forested headwater catchment. Soils were described and characterized at 172 locations within Watershed 3, the...

Fresh and preserved green fodder modify effects of urinary acidifiers on urine pH of horses.

Science.gov (United States)

Goren, G; Fritz, J; Dillitzer, N; Hipp, B; Kienzle, E

2014-04-01

Hay stabilises urine pH in horses. It is unknown whether this is an effect of structure or of chemical composition. In this study, four ponies (230-384 kg body weight [BW]) were fed six different diets with either a structure or a composition similar to hay with and without acidifiers in a cross-over experimental design in amounts to maintain body weight with the following main compounds: Fresh grass (GRASS), alfalfa hay (ALF), grass cobs (COBS), grass silage (SIL), straw (STR) or extruded straw (STRe) for 2 to 10 days. Urine pH was measured in all trials, blood pH, blood base excess and bicarbonate as well as mineral balance were determined in GRASS, ALF, STR and STRe. In the trials with straw and extruded straw, urine pH decreased significantly (STR control: 7.8 ± 0.23, acidifier: 5.2 ± 0.38) when acidifiers were added, whereas in all other diets that were based on fresh or preserved green fodder, pH did not decrease below 7. Blood pH was similarly affected by diet and acidifiers. Acidifiers had little effect on the pre-prandial blood pH, only in diet STR there was a significant reduction in relation to control. Post-prandial blood pH was significantly reduced by acidifiers in all diets. Blood bicarbonate and base excess showed corresponding effects. Faecal and renal mineral excretion and apparent mineral digestibility were not systematically affected by diet or acidifiers except for chloride. Chloride added as inorganic chloride salt had an even better apparent digestibility than chloride originating from feed. Because only green plant material stabilised acid base balance, chlorophyll and its metabolites are discussed as potential mediators of the effect of green fodder on acid base balance. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

Drought propagation and its relation with catchment biophysical characteristics

Science.gov (United States)

Alvarez-Garreton, C. D.; Lara, A.; Garreaud, R. D.

2016-12-01

Droughts propagate in the hydrological cycle from meteorological to soil moisture to hydrological droughts. To understand the drivers of this process is of paramount importance since the economic and societal impacts in water resources are directly related with hydrological droughts (and not with meteorological droughts, which have been most studied). This research analyses drought characteristics over a large region and identify its main exogenous (climate forcing) and endogenous (biophysical characteristics such as land cover type and topography) explanatory factors. The study region is Chile, which covers seven major climatic subtypes according to Köppen system, it has unique geographic characteristics, very sharp topography and a wide range of landscapes and vegetation conditions. Meteorological and hydrological droughts (deficit in precipitation and streamflow, respectively) are characterized by their durations and standardized deficit volumes using a variable threshold method, over 300 representative catchments (located between 27°S and 50°S). To quantify the propagation from meteorological to hydrological drought, we propose a novel drought attenuation index (DAI), calculated as the ratio between the meteorological drought severity slope and the hydrological drought severity slope. DAI varies from zero (catchment that attenuates completely a meteorological drought) to one (the meteorological drought is fully propagated through the hydrological cycle). This novel index provides key (and comparable) information about drought propagation over a wide range of different catchments, which has been highlighted as a major research gap. Similar drought indicators across the wide range of catchments are then linked with catchment biophysical characteristics. A thorough compilation of land cover information (including the percentage of native forests, grass land, urban and industrial areas, glaciers, water bodies and no vegetated areas), catchment physical

Catchment-scale Validation of a Physically-based, Post-fire Runoff and Erosion Model

Science.gov (United States)

Quinn, D.; Brooks, E. S.; Robichaud, P. R.; Dobre, M.; Brown, R. E.; Wagenbrenner, J.

2017-12-01

The cascading consequences of fire-induced ecological changes have profound impacts on both natural and managed forest ecosystems. Forest managers tasked with implementing post-fire mitigation strategies need robust tools to evaluate the effectiveness of their decisions, particularly those affecting hydrological recovery. Various hillslope-scale interfaces of the physically-based Water Erosion Prediction Project (WEPP) model have been successfully validated for this purpose using fire-effected plot experiments, however these interfaces are explicitly designed to simulate single hillslopes. Spatially-distributed, catchment-scale WEPP interfaces have been developed over the past decade, however none have been validated for post-fire simulations, posing a barrier to adoption for forest managers. In this validation study, we compare WEPP simulations with pre- and post-fire hydrological records for three forested catchments (W. Willow, N. Thomas, and S. Thomas) that burned in the 2011 Wallow Fire in Northeastern Arizona, USA. Simulations were conducted using two approaches; the first using automatically created inputs from an online, spatial, post-fire WEPP interface, and the second using manually created inputs which incorporate the spatial variability of fire effects observed in the field. Both approaches were compared to five years of observed post-fire sediment and flow data to assess goodness of fit.

Transboundary air pollution in Europe. Part 2: Numerical addendum to emissions, dispersion and trends of acidifying and eutrophying agents

Energy Technology Data Exchange (ETDEWEB)

Berge, Erik [ed.

1997-12-31

This report was prepared for the twenty first session of the Steering Body of EMEP (Co-operative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air Pollutants in Europe). It presents the numerical fields and budgets of the acidifying and eutrophying air pollution in the form of three appendices: annual average air concentrations of acidifying and eutrophying species, 1996; country-to-country deposition budgets for acidifying/eutrophying air pollutants, 1985-95; and grid square deposition of acidifying/eutrophying components allocated to emitting countries, mean 1985-95. 19 figs.

Behaviour of arsenic in forested catchments following a high-pollution period

Czech Academy of Sciences Publication Activity Database

Novák, M.; Erbanová, L.; Fottová, D.; Cudlín, Pavel; Kubena, A.

2011-01-01

Roč. 159, č. 1 (2011), s. 204-211 ISSN 0269-7491 Institutional research plan: CEZ:AV0Z60870520 Keywords : Arsenic * Catchment * Soil * Flux * Mass balance * Biomass Subject RIV: DD - Geochemistry Impact factor: 3.746, year: 2011

Sources of 137Cs fluvial export from a forest catchment evaluated by stable carbon and nitrogen isotopic characterization of organic matter

International Nuclear Information System (INIS)

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

2017-01-01

Fluvial export of particulate and dissolved 137 Cs was investigated to reveal its sources and transfer mechanisms in a broadleaved forest catchment using a continuous collection system. The finest size fraction (<75 µm), consisting of decomposed litter and surface mineral soil, was the dominant fraction in the particulate 137 Cs load, although the contribution of coarser size fractions increased during high water discharge in 2014. The dissolved 137 Cs originated from the decomposition of 137 Cs-contaminated litter. Temporal changes in 137 Cs distribution in the litter-mineral soil system indicated that the dissolved 137 Cs load will be moderated in several years, while particulate 137 Cs load has the potential to continue for a long time. (author)

Hydrological consequences of land-use change from forest to pasture in the Atlantic rain forest region

Directory of Open Access Journals (Sweden)

Luiz Antonio Martinelli

2012-12-01

Full Text Available The Atlantic rain forest is the most endangered ecosystem in Brazil. Its degradation has started since 1500 when the European settlers arrived. Despite of all land use changes that have occurred, hydrological studies carried out in this biome have been limited to hydrological functioning of rain forests only. In order to understand the hydrological consequences of land-use change from forest to pasture, we described the hydrological functioning of a pasture catchment that was previously covered by tropical rain forest. To reach this goal we measured the precipitation, soil matric potential, discharge, surface runoff and water table levels during one year. The results indicated that there is a decrease in surface soil saturated hydraulic conductivity. However, as low intensity rainfall prevails, the lower water conductivity does not necessarily leads to a substantially higher surface runoff generation. Regarding soil water matric potential, the pasture presented higher moisture levels than forest during the dry season. This increase in soil moisture implies in higher water table recharge that, in turn, explain the higher runoff ratio. This way, land-use change conversion from forest to pasture implies a higher annual streamflow in pasture catchments. Nonetheless, this increase in runoff due to forest conversion to pasture implies in losses of biological diversity as well as lower soil protection.

impacts of rainfall and forest cover change on runoff in small ...

African Journals Online (AJOL)

the relationship between rainfall and runoff in the two catchments has changed. Furthermore .... The monthly rainfall data for Namadzi catchment that was used in this .... land cover change with a big jump of forest planted after the 1990s. Fig.

Impacts of the post-fire erosion processes compared with the agricultural erosion rates for a mountain catchment in NW Iberia

Science.gov (United States)

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

2014-05-01

Mediterranean ecosystems are very vulnerable to soil erosion by water due to particular characteristics of climate, lithology and land use history. Moreover, the foreseen climate changes might worsen land degradation and desertification, in which soil erosion has been classified as one of the most important driving forces. In this context, the frequent forest fires seen in some Mediterranean regions can case disturbances to vegetation cover and enhance soil erosion processes. This work addresses this issue for the Caramulo mountain range, NW Iberia. In the past century, large land use changes occurred due to massive afforestation. Changes from mixed natural forest cover and shrublands to Pine, the introduction of Eucalyptus plantations and, more recently, a trend for the substitution of pines by eucalypts, are the evidence of a large and rapid land use change in the last decades. Forest fires started to occur as afforestation proceeded, as a consequence of the disappearance of pasturage and accumulation of highly inflammable material; they became more frequent after the 1960's and became a determinant factor for land use changes in this region. Data collection focused on the Macieira de Alcoba catchment, a headwater agro-forested catchment (94 ha) located in this region. It has a wet Mediterranean climate, with an average annual rainfall of about 1300 mm (2002-2012), concentrated in autumn and winter, while spring and summer are dryer seasons. The mean annual temperature is 14°C and in summer it can reach 35°C. The land use is mixed, with forest and agriculture lands covering respectively 60 and 35% of the catchment area, 5% being built-up areas in the village of Macieira de Alcoba. In the last decades, this catchment suffered several forest fires (in 1969, 1986, 1991, and 2011). Erosion processes are related with periods of low vegetation cover in autumn in fields with a pasture-corn rotation, but also with forest plantations after clear-cutting and especially

The impact of urbanization on subsurface flow paths - A paired-catchment isotopic study

Science.gov (United States)

Bonneau, Jeremie; Burns, Matthew J.; Fletcher, Tim D.; Witt, Roman; Drysdale, Russell N.; Costelloe, Justin F.

2018-06-01

Urbanization disturbs groundwater flow through the sealing of native soils with impervious surfaces and through modifications to the subsoil by constructed drainage and other infrastructure (trenches and excavations, e.g. water supply). The impact of these disturbances on groundwater contributions to urban streams (i.e. baseflow) is poorly understood. While high flows caused by impervious runoff to streams are a common focus of urban studies, the route taken by groundwater to become streamflow in urban landscapes is not generally considered. To assess the impact of urbanization on groundwater sources to streams, both rainfall and baseflow were sampled weekly for stable isotopes of water in two nearby streams-one draining a peri-urban catchment and the other draining a forested, natural catchment. In addition, to study the rate of groundwater discharge to the stream, monthly baseflow recession behavior was investigated. We found that baseflow in the forested catchment was constant in stable isotope values (δ18O = -5.73‰ ± 0.14‰) throughout the year. Monthly baseflow recession constants were close to 1 and had little variation (ranging 0.951-0.992), indicating a well-mixed groundwater store and long residence times. In contrast, the urban baseflow isotopic composition featured distinct seasonal variations (δ18O = -3.35‰ ± 1.20‰ from October to March and δ18O = -4.54‰ ± 0.43‰ from April to September) and high week-to-week variability in summer, reflecting a contribution of recent rainfall to baseflow. Recession constants were lower (ranging 0.727-0.955) with pronounced seasonal variations, suggesting shorter residence times and the likely presence of a variety of stores and pathways. These results provide evidence that the urban catchment has diversified groundwater pathways, and its groundwater storage is drained faster than that of the forested catchment. It highlights some of the subsurface hydrological consequences of urbanization. Restoring low

Forest condition and chemical characteristics of atmospheric depositions: research and monitoring network in Lombardy

Directory of Open Access Journals (Sweden)

Flaminio DI GIROLAMO

2002-09-01

acidifying element and as a nutrient. To estimate the input-output budget of the catchment, monitoring was extended to stream water and soil solution.

Hydrochemistry in the Tropical Forested River: A Case Study in Nee Soon Catchment Streams

Science.gov (United States)

Nguyen, T. C. T.; WIN, S. H.; Lim, M. H.; Pai, K.; Khairun Nisha, B. M. R.; Ziegler, A. D.; Wasson, R.; Cantarero, S. I.

2016-12-01

A total of 779 water samples from the Nee Soon Nature Reserve, a 5km2 catchment in humid tropical Singapore, were collected in low-flow (May 2014 to Nov 2015) and high-flow (May 2014 to June 2015) conditions for determination of spatial and temporal distributions of major ions (Na+, Ca2+, K+, Mg2+, Cl-, HCO3-, NO3-, SO42- and F-) in the streams. In low-flow conditions all cations and Cl-, HCO3-, SO42- showed significant enrichment in the lower compared to the upper catchment, whereas, NO3- and F- had the opposite pattern. In high-flow conditions, the spatial distribution patterns of the ions was largely unchanged across the catchment except that F- was enriched in the lower compared to the upper catchment. Except for Cl-, HCO3- and NO3-, all other ions were higher in storm periods. Among possible sources (atmospheric input, anthropogenic impact and rock weathering), rainfall played an important role in controlling river Cl- and Na+; silicate rock weathering was possibly the source for Ca2+,Mg2+, HCO3- and some of the Na+; all of the SO42- probably comes from pollution by anthropogenic activities. This study provides new data and insights for the understudied South East Asia region.

Spatial and temporal variability of N2O emissions in a subtropical forest catchment in China

Directory of Open Access Journals (Sweden)

J. Zhu

2013-03-01

Full Text Available Subtropical forests in southern China have received chronically large amounts of atmogenic nitrogen (N, causing N saturation. Recent studies suggest that a significant proportion of the N input is returned to the atmosphere, in part as nitrous oxide (N2O. We measured N2O emission fluxes by closed chamber technique throughout two years in a Masson pine-dominated headwater catchment with acrisols (pH ~ 4 at Tieshanping (Chongqing, SW China and assessed the spatial and temporal variability in two landscape elements typical for this region: a mesic forested hillslope (HS and a hydrologically connected, terraced groundwater discharge zone (GDZ in the valley bottom. High emission rates of up to 1800 μg N2O-N m−2 h−1 were recorded on the HS shortly after rain storms during monsoonal summer, whereas emission fluxes during the dry winter season were generally low. Overall, N2O emission was lower in GDZ than on HS, rendering the mesic HS the dominant source of N2O in this landscape. Temporal variability of N2O emissions on HS was largely explained by soil temperature (ST and moisture, pointing at denitrification as a major process for N removal and N2O production. The concentration of nitrate (NO3− in pore water on HS was high even in the rainy season, apparently never limiting denitrification and N2O production. The concentration of NO3− decreased along the terraced GDZ, indicating efficient N removal, but with moderate N2O-N loss. The extrapolated annual N2O fluxes from soils on HS (0.54 and 0.43 g N2O-N m−2 yr−1 for a year with a wet and a dry summer, respectively are among the highest N2O fluxes reported from subtropical forests so far. Annual N2O-N emissions amounted to 8–10% of the annual atmogenic N deposition, suggesting that forests on acid soils in southern China are an important, hitherto overlooked component of the anthropogenic N2O budget.

Response of floodplain sedimentation to catchment disturbances in different environments

Science.gov (United States)

Notebaert, B.; Houbrechts, G.; Verstraeten, G.; Petit, F.

2009-04-01

factor. In the Lienne floodplain, around 80% of the sediments present in the main valley were deposited before 1350AD, thus before the main period of forest clearance. On the other hand, about 50% of the Holocene sediment present in a main tributary (Chavanne) was deposited after 1537 (local start of iron industry). This difference with the main valley can be explained by a difference in physical settings of the river (valley slope, stream power). These results show that the physical settings of river valleys determine how sensible the river systems are to catchment disturbances. Floodplain deposition is determined by an interplay of hill slope sediment delivery (hill slope erosion and connectivity) and physical settings of the valley itself (valley slope, discharge). As a result, quantification of floodplain deposition alone, cannot be used as a measure for historic soil erosion within a catchment or to determine intensity of human impact on the catchment.

The fate of sulfate in acidified pig slurry during storage and following application to cropped soil

DEFF Research Database (Denmark)

Eriksen, Jørgen; Sørensen, Peter; Elsgaard, Lars

2008-01-01

-available sulfate form. Microbial sulfate reduction during storage of acidified pig slurry was limited, presumably due to initial pH effects and a limitation in the availability of easily degradable organic matter. Sulfide accumulation was observed during storage but the sulfide levels in acidified slurry did...

Catchment Morphing (CM): A Novel Approach for Runoff Modeling in Ungauged Catchments

Science.gov (United States)

Zhang, Jun; Han, Dawei

2017-12-01

Runoff prediction in ungauged catchments has been one of the major challenges in the past decades. However, due to the tremendous heterogeneity of the catchments, obstacles exist in deducing model parameters for ungauged catchments from gauged ones. We propose a novel approach to predict ungauged runoff with Catchment Morphing (CM) using a fully distributed model. CM is defined as by changing the catchment characteristics (area and slope here) from the baseline model built with a gauged catchment to model the ungauged ones. As a proof of concept, a case study on seven catchments in the UK has been used to demonstrate the proposed scheme. Comparing the predicted with measured runoff, the Nash-Sutcliffe efficiency (NSE) varies from 0.03 to 0.69 in six catchments. Moreover, NSEs are significantly improved (up to 0.81) when considering the discrepancy of percentage runoff between the target and baseline catchments. A distinct advantage has been experienced by comparing the CM with a traditional method for ungauged catchments. The advantages are: (a) less demand of the similarity between the baseline catchment and the ungauged catchment, (b) less demand of available data, and (c) potentially widely applicable in varied catchments. This study demonstrates the feasibility of the proposed scheme as a potentially powerful alternative to the conventional methods in runoff predictions of ungauged catchments. Clearly, more work beyond this pilot study is needed to explore and develop this new approach further to maturity by the hydrological community.

Effects of wildfire on catchment runoff response: a modeling approach to detect changes in snow-dominated forested catchments

Science.gov (United States)

Jan Seibert; Jeffrey J. McDonnell; Richard D. Woodsmith

2010-01-01

Wildfire is an important disturbance affecting hydrological processes through alteration of vegetation cover and soil characteristics. The effects of fire on hydrological systems at the catchment scale are not well known, largely because site specific data from both before and after wildfire are rare. In this study a modelling approach was employed for change detection...

Quantifying Hydrological Ecosystem Services of Various Land Covers and Uses on Small Experimental Catchments within the Panama Canal Watershed: The Agua Salud Project

Science.gov (United States)

Crouch, T. D.; Ogden, F. L.; Agua Salud Project

2011-12-01

As a part of the Agua Salud Project, a baseline characterization of hydrologic processes on the small catchment scale (~0.24 to 2.0 km2) is assessed across different land uses and covers typical to rural Panama. The land covers being monitored include a mature secondary forest, a disturbed catchment with a mosaic of various aged secondary growth and agricultural use, an active pasture and a monoculture invasive grass site as experimental controls, and two treated catchments that were recently abandoned pastures converted to teak and native species timber plantations. The catchments are found within Panama's protected Soberania National Park and the adjacent headwaters of the Agua Salud and Mendoza Rivers, all part of the greater Panama Canal Watershed. Using hydrological data from the first two and a half years of the project, three main ecosystem services are observed. The forested area exhibited lower storm event peaks, decreased flashiness, and greater stream flow during the dry season compared to the disturbed mosaic site. Lower hydrograph peaks and flashiness mitigate the risk of substantial flood damage during the major flood events generally seen in Panama between October and December. The mature forest (1.35 km2) catchment has shown lower average flood peaks in comparison to the disturbed site. For storm peaks less than 6 mm/hr, flood peaks are on average 51% lower. For storm peaks greater than 6 mm/hr, flood peaks are approximately 40% lower. In 1998, draft restrictions were imposed in the Panama Canal because of a deficit of dry season water after an El Niño-Southern Oscillation resulted in decreased wet season rainfall. The water that is available during the end of the dry season has the potential to insure the full operation of the Canal during El Niño drought years. Toward the end of the dry season (March through May) our data shows that roughly 34% more water was available during a relatively dry year with respect to antecedent wet season rainfall

Anomaly in the rainfall-runoff behaviour of the Meuse catchment. Climate, land-use, or land-use management?

Directory of Open Access Journals (Sweden)

F. Fenicia

2009-09-01

Full Text Available The objective of this paper is to investigate the time variability of catchment characteristics in the Meuse basin through its effect on catchment response. The approach uses a conceptual model to represent rainfall-runoff behaviour of this catchment, and evaluates possible time-dependence of model parameters. The main hypothesis is that conceptual model parameters, although not measurable quantities, are representative of specific catchment attributes (e.g. geology, land-use, land management, topography. Hence, we assume that eventual trends in model parameters are representative of catchment attributes that may have changed over time. The available hydrological record involves ninety years of data, starting in 1911. During this period the Meuse catchment has undergone significant modifications. The catchment structural modifications, although documented, are not available as "hard-data". Hence, our results should be considered as "plausible hypotheses". The main motivation of this work is the "anomaly" found in the rainfall runoff behaviour of the Meuse basin, where ninety years of rainfall-runoff simulations show a consistent overestimation of the runoff in the period between 1930 and 1965. Different authors have debated possible causes for the "anomaly", including climatic variability, land-use change and data errors. None of the authors considered the way in which the land is used by for instance agricultural and forestry practises. This aspect influenced the model design, which has been configured to account for different evaporation demand of growing forest. As a result of our analysis, we conclude that the lag time of the catchment has decreased significantly over time, which we attribute to more intensive drainage and river training works. Furthermore, we hypothesise that forest rotation has had a significant impact on the evaporation of the catchment. These results contrast with previous studies, where the effect of land-use change on

The catchment based approach using catchment system engineering

Science.gov (United States)

Jonczyk, Jennine; Quinn, Paul; Barber, Nicholas; Wilkinson, Mark

2015-04-01

The catchment based approach (CaBa) has been championed as a potential mechanism for delivery of environmental directives such as the Water Framework Directive in the UK. However, since its launch in 2013, there has been only limited progress towards achieving sustainable, holistic management, with only a few of examples of good practice ( e.g. from the Tyne Rivers trust). Common issues with developing catchment plans over a national scale include limited data and resources to identify issues and source of those issues, how to systematically identify suitable locations for measures or suites of measures that will have the biggest downstream impact and how to overcome barriers for implementing solutions. Catchment System Engineering (CSE) is an interventionist approach to altering the catchment scale runoff regime through the manipulation of hydrological flow pathways throughout the catchment. A significant component of the runoff generation can be managed by targeting hydrological flow pathways at source, such as overland flow, field drain and ditch function, greatly reducing erosive soil losses. Coupled with management of farm nutrients at source, many runoff attenuation features or measures can be co-located to achieve benefits for water quality and biodiversity. A catchment, community-led mitigation measures plan using the CSE approach will be presented from a catchment in Northumberland, Northern England that demonstrate a generic framework for identification of multi-purpose features that slow, store and filter runoff at strategic locations in the landscape. Measures include within-field barriers, edge of field traps and within-ditch measures. Progress on the implementation of measures will be reported alongside potential impacts on the runoff regime at both local and catchment scale and costs.

An Evaluation of the Role of Ozone, Acid Deposition, and other Airborne Pollutants in the Forests of Eastern North America

Science.gov (United States)

J.H.B. Garner; Terry Pagano; Ellis B. Cowling

1989-01-01

Existing knowledge on air pollutants that occur in the forests of eastern North America is summarized and interpreted.Resolution is sought to the conflict between the prevailing scientific judgment that ozone and other oxidants are most likely to be damaging eastern forests and the prevailing public perception that acidic and acidifying substances are the most likely...

The subcatchment- and catchment-scale hydrology of a boreal headwater peatland complex with sporadic permafrost.

Science.gov (United States)

Sonnentag, O.; Helbig, M.; Connon, R.; Hould Gosselin, G.; Ryu, Y.; Karoline, W.; Hanisch, J.; Moore, T. R.; Quinton, W. L.

2017-12-01

The permafrost region of the Northern Hemisphere has been experiencing twice the rate of climate warming compared to the rest of the Earth, resulting in the degradation of the cryosphere. A large portion of the high-latitude boreal forests of northwestern Canada grows on low-lying organic-rich lands with relative warm and thin isolated, sporadic and discontinuous permafrost. Along this southern limit of permafrost, increasingly warmer temperatures have caused widespread permafrost thaw leading to land cover changes at unprecedented rates. A prominent change includes wetland expansion at the expense of Picea mariana (black spruce)-dominated forest due to ground surface subsidence caused by the thawing of ice-rich permafrost leading to collapsing peat plateaus. Recent conceptual advances have provided important new insights into high-latitude boreal forest hydrology. However, refined quantitative understanding of the mechanisms behind water storage and movement at subcatchment and catchment scales is needed from a water resources management perspective. Here we combine multi-year daily runoff measurements with spatially explicit estimates of evapotranspiration, modelled with the Breathing Earth System Simulator, to characterize the monthly growing season catchment scale ( 150 km2) hydrological response of a boreal headwater peatland complex with sporadic permafrost in the southern Northwest Territories. The corresponding water budget components at subcatchment scale ( 0.1 km2) were obtained from concurrent cutthroat flume runoff and eddy covariance evapotranspiration measurements. The highly significant linear relationships for runoff (r2=0.64) and evapotranspiration (r2=0.75) between subcatchment and catchment scales suggest that the mineral upland-dominated downstream portion of the catchment acts hydrologically similar to the headwater portion dominated by boreal peatland complexes. Breakpoint analysis in combination with moving window statistics on multi

Linking sediment fingerprinting and modeling outputs for a Spanish Pyrenean river catchment.

Science.gov (United States)

Palazón, Leticia; Latorre, Borja; Gaspar, Leticia; Blake, Williams H.; Smith, Hugh G.; Navas, Ana

2015-04-01

Indirect techniques to study fine sediment redistribution in river catchments could provide unique and diverse information, which, when combined become a powerful tool to address catchment management problems. Such combinations could solve limitations of individual techniques and provide different lines of information to address a particular problem. The Barasona reservoir has suffered from siltation since its construction, with the loss of over one third of its storage volume in around 30 study years (period 1972-1996). Information on sediment production from tributary catchments for the reservoir is required to develop management plans for maintaining reservoir sustainability. Large spatial variability in sediment delivery was found in previous studies in the Barasona catchment and the major sediment sources identified included badlands developed in the middle part of the catchment and the agricultural fields in its lower part. From the diverse range of indirect techniques, fingerprinting sediment sources and computer models could be linked to obtain a more holistic view of the processes related to sediment redistribution in the Barasona river catchment (1509 km2, Central Spanish Pyrenees), which comprises agricultural and forest land uses. In the present study, the results from a fingerprinting procedure and the SWAT model were compared and combined to improve the knowledge of land use sediment source contributions to the reservoir. Samples from the study catchment were used to define soil parameters for the model and for fingerprinting the land use sources. The fingerprinting approach provided information about relative contributions from land use sources to the superficial sediment samples taken from the reservoir infill. The calibration and validation of the model provided valuable information, for example on the timescale of sediment production from the different land uses within the catchment. Linking results from both techniques enabled us to achieve a

Implications for Forest Resource Degradation and Deforestation ...

African Journals Online (AJOL)

Effects of Socio-Economic Status and Food Consumption Pattern on Household Energy uses: Implications for Forest Resource Degradation and Deforestation around Wondo Genet Catchments, South-Central Ethiopia.

Predicting long-term streamflow variability in moist eucalypt forests using forest growth models and a sapwood area index

Science.gov (United States)

Jaskierniak, D.; Kuczera, G.; Benyon, R.

2016-04-01

A major challenge in surface hydrology involves predicting streamflow in ungauged catchments with heterogeneous vegetation and spatiotemporally varying evapotranspiration (ET) rates. We present a top-down approach for quantifying the influence of broad-scale changes in forest structure on ET and hence streamflow. Across three catchments between 18 and 100 km2 in size and with regenerating Eucalyptus regnans and E. delegatensis forest, we demonstrate how variation in ET can be mapped in space and over time using LiDAR data and commonly available forest inventory data. The model scales plot-level sapwood area (SA) to the catchment-level using basal area (BA) and tree stocking density (N) estimates in forest growth models. The SA estimates over a 69 year regeneration period are used in a relationship between SA and vegetation induced streamflow loss (L) to predict annual streamflow (Q) with annual rainfall (P) estimates. Without calibrating P, BA, N, SA, and L to Q data, we predict annual Q with R2 between 0.68 and 0.75 and Nash Sutcliffe efficiency (NSE) between 0.44 and 0.48. To remove bias, the model was extended to allow for runoff carry-over into the following year as well as minor correction to rainfall bias, which produced R2 values between 0.72 and 0.79, and NSE between 0.70 and 0.79. The model under-predicts streamflow during drought periods as it lacks representation of ecohydrological processes that reduce L with either reduced growth rates or rainfall interception during drought. Refining the relationship between sapwood thickness and forest inventory variables is likely to further improve results.

Catchment-Wide Atmospheric Greenhouse Gas Exchange as Influenced by Land Use Diversity

DEFF Research Database (Denmark)

Herbst, Mathias; Friborg, Thomas; Ringgaard, Rasmus

2011-01-01

The turbulent fl uxes of carbon dioxide between the land surface and the atmosphere were measured with the eddy covariance technique above three contrasO ng land use types in the Skjern River catchment in western Denmark, namely an agricultural area, a forest plantation, and a wet grassland...... of the site by one-third. At the agricultural site this sink strength was reduced by 9% through the N2O emissions. Scaled up to the catchment, the observed net uptake of CO2 by the land surface was reduced by roughly one-tenth, in terms of CO2 equivalents, due to the emission of CH4 and N2O....

A novel approach for runoff modelling in ungauged catchments by Catchment Morphing

Science.gov (United States)

Zhang, J.; Han, D.

2017-12-01

Runoff prediction in ungauged catchments has been one of the major challenges in the past decades. However, due to the tremendous heterogeneity of hydrological catchments, obstacles exist in deducing model parameters for ungauged catchments from gauged ones. We propose a novel approach to predict ungauged runoff with Catchment Morphing (CM) using a fully distributed model. CM is defined as by changing the catchment characteristics (area and slope here) from the baseline model built with a gauged catchment to model the ungauged ones. The advantages of CM are: (a) less demand of the similarity between the baseline catchment and the ungauged catchment, (b) less demand of available data, and (c) potentially applicable in varied catchments. A case study on seven catchments in the UK has been used to demonstrate the proposed scheme. To comprehensively examine the CM approach, distributed rainfall inputs are utilised in the model, and fractal landscapes are used to morph the land surface from the baseline model to the target model. The preliminary results demonstrate the feasibility of the approach, which is promising in runoff simulation for ungauged catchments. Clearly, more work beyond this pilot study is needed to explore and develop this new approach further to maturity by the hydrological community.

Does road salting confound the recovery of the microcrustacean community in an acidified lake?

Science.gov (United States)

Jensen, Thomas Correll; Meland, Sondre; Schartau, Ann Kristin; Walseng, Bjørn

2014-04-15

Numerous boreal lakes across the Northern Hemisphere recovering from acidification are experiencing a simultaneous increase in chloride (Cl) concentrations from road salting. Increasing Cl may have profound effects on the lake ecosystem. We examine if an increase in Cl from road salting has modified the recovery of the microcrustacean community in an acidified boreal lake undergoing chemical recovery (study lake). Results from the study lake were compared with an acidified "reference lake". The community changed during the study period in the study lake mainly driven by the reduction in acidification pressure. Despite the community changes and an increase in species richness, the absence of several acid sensitive species, previously occurring in the lake, indicates a delayed biological recovery relative to the chemical recovery. Moreover, changes in occurrence of acid sensitive and acid tolerant species indicated that the biological recovery was slower in the study lake compared to the "reference". Although recurrent episodes of high aluminum and low pH and decreasing Ca are likely important factors for the delay, these do not explain, for instance, the shift from Cyclops scutifer to Bosmina longispina in the study lake. Although the contribution of Cl was not significant, the correlation between Cl and the variation in microcrustacean community was twice as high in the study lake compared to the "reference". We argue that small, sheltered forest lakes may be especially sensitive to increased Cl levels, through changes in pattern of stratification, thus providing a mechanism for the shift from C. scutifer to B. longispina. The reduction of the acidification pressure seems to override the Cl effects on microcrustaceans at low Cl levels in salt-affected lakes recovering from acidification. However, prognoses for growing traffic and increasing road salting raise concern for many recovering lakes located in proximity to roads and urbanized areas. Copyright © 2014

Relating land use patterns to stream nutrient levels in red soil agricultural catchments in subtropical central China.

Science.gov (United States)

Wang, Yi; Li, Yong; Liu, Xinliang; Liu, Feng; Li, Yuyuan; Song, Lifang; Li, Hang; Ma, Qiumei; Wu, Jinshui

2014-09-01

Land use has obvious influence on surface water quality; thus, it is important to understand the effects of land use patterns on surface water quality. This study explored the relationships between land use patterns and stream nutrient levels, including ammonium-N (NH4 (+)-N), nitrate-N (NO3 (-)-N), total N (TN), dissolved P (DP), and total P (TP) concentrations, in one forest and 12 agricultural catchments in subtropical central China. The results indicated that the TN concentrations ranged between 0.90 and 6.50 mg L(-1) and the TP concentrations ranged between 0.08 and 0.53 mg L(-1), showing that moderate nutrient pollution occurred in the catchments. The proportional areal coverages of forests, paddy fields, tea fields, residential areas, and water had distinct effects on stream nutrient levels. Except for the forest, all studied land use types had a potential to increase stream nutrient levels in the catchments. The land use pattern indices at the landscape level were significantly correlated to N nutrients but rarely correlated to P nutrients in stream water, whereas the influence of the land use pattern indices at the class level on stream water quality differentiated among the land use types and nutrient species. Multiple regression analysis suggested that land use pattern indices at the class level, including patch density (PD), largest patch index (LPI), mean shape index (SHMN), and mean Euclidian nearest neighbor distance (ENNMN), played an intrinsic role in influencing stream nutrient quality, and these four indices explained 35.08 % of the variability of stream nutrient levels in the catchments (pstream nutrient pollution in subtropical central China.

Bibliography of publications and manuscripts relating to the Bohemian/Bavarian Forest lakes

Czech Academy of Sciences Publication Activity Database

Vrba, Jaroslav (ed.)

2000-01-01

Roč. 4, č. 4 (2000), s. 259-278 ISSN 1211-7420. [Acidified Lakes in the Bohemian/Bavarian Forest - History, Present and Future. Č. Budějovice, 21.03.2000-23.03.2000] R&D Projects: GA ČR GA206/97/0072; GA ČR GA206/98/0727 Subject RIV: DA - Hydrology ; Limnology

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

A probabilistic multidimensional approach to quantify large wood recruitment from hillslopes in mountainous-forested catchments

Science.gov (United States)

Cislaghi, Alessio; Rigon, Emanuel; Lenzi, Mario Aristide; Bischetti, Gian Battista

2018-04-01

Large wood (LW) plays a key role in physical, chemical, environmental, and biological processes in most natural and seminatural streams. However, it is also a source of hydraulic hazard in anthropised territories. Recruitment from fluvial processes has been the subject of many studies, whereas less attention has been given to hillslope recruitment, which is linked to episodic and spatially distributed events and requires a reliable and accurate slope stability model and a hillslope-channel transfer model. The purpose of this study is to develop an innovative LW hillslope-recruitment estimation approach that combines forest stand characteristics in a spatially distributed form, a probabilistic multidimensional slope stability model able to include the reinforcement exerted by roots, and a hillslope-channel transfer procedure. The approach was tested on a small mountain headwater catchment in the eastern Italian Alps that is prone to shallow landslide and debris flow phenomena. The slope stability model (that had not been calibrated) provided accurate performances, in terms of unstable areas identification according to the landslide inventory (AUC = 0.832) and of LW volume estimation in comparison with LW volume produced by inventoried landslides (7702 m3 corresponding to a recurrence time of about 30 years in the susceptibility curve). The results showed that most LW potentially mobilised by landslides does not reach the channel network (only about 16%), in agreement with the few data reported by other studies, as well as the data normalized for unit length of channel and unit length of channel per year (0-116 m3/km and 0-4 m3/km y-1). This study represents an important contribution to LW research. A rigorous and site-specific estimation of LW hillslope recruitment should, in fact, be an integral part of more general studies on LW dynamics, for forest planning and management, and positioning in-channel wood retention structures.

Impact of Catchment Area Activities on Water Quality in Small Retention Reservoirs

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Oszczapińska Katarzyna

2018-01-01

Full Text Available The aim of the study was to evaluate catchment area impact on small water reservoirs condition in Podlasie. The researches were conducted in two different catchment areas. Topiło reservoir, located in Podlasie area in the south-east of Białowieża Forest, has typical sylvan catchment. Second reservoir, Dojlidy, is located also in Podlasie, in the south-east of Białystok as a part of Dojlidy Ponds. In contrast to Topiło, Dojlidy has agricultural catchment. Water samples collected from five sites along each reservoir were analysed for the presence of total nitrogen and phosphorus, chlorophyll “a”, reaction, turbidity and conductivity. Researches took place in spring, summer and autumn 2013 (Topiło Lake and 2014/2015 (Dojlidy. The lowest trophic state was observed in autumn and the highest in summer. Because of the high loads of phosphorus received by the reservoirs, this element did not limit primary production. Calculated TSI values based on total phosphorus were always markedly higher than calculated on chlorophyll-a and total nitrogen. Both reservoirs demonstrated TSI indexes specific to hypertrophic lakes due to large amount of total phosphorus.

Impact of Catchment Area Activities on Water Quality in Small Retention Reservoirs

Science.gov (United States)

Oszczapińska, Katarzyna; Skoczko, Iwona; Szczykowska, Joanna

2018-02-01

The aim of the study was to evaluate catchment area impact on small water reservoirs condition in Podlasie. The researches were conducted in two different catchment areas. Topiło reservoir, located in Podlasie area in the south-east of Białowieża Forest, has typical sylvan catchment. Second reservoir, Dojlidy, is located also in Podlasie, in the south-east of Białystok as a part of Dojlidy Ponds. In contrast to Topiło, Dojlidy has agricultural catchment. Water samples collected from five sites along each reservoir were analysed for the presence of total nitrogen and phosphorus, chlorophyll "a", reaction, turbidity and conductivity. Researches took place in spring, summer and autumn 2013 (Topiło Lake) and 2014/2015 (Dojlidy). The lowest trophic state was observed in autumn and the highest in summer. Because of the high loads of phosphorus received by the reservoirs, this element did not limit primary production. Calculated TSI values based on total phosphorus were always markedly higher than calculated on chlorophyll-a and total nitrogen. Both reservoirs demonstrated TSI indexes specific to hypertrophic lakes due to large amount of total phosphorus.

The Impacts of Pine Tree Die-Off on Snow Accumulation and Distribution at Plot to Catchment Scales

Science.gov (United States)

Biederman, J. A.; Harpold, A. A.; Gutmann, E. D.; Reed, D. E.; Gochis, D. J.; Brooks, P. D.

2011-12-01

Seasonal snow cover is a primary water source throughout much of Western North America, where insect-induced tree die-off is changing the montane landscape. Widespread mortality from insects or drought differs from well-studied cases of fire and logging in that tree mortality is not accompanied by other immediate biophysical changes. Much of the impacted landscape is a mosaic of stands of varying species, structure, management history and health overlain on complex terrain. To address the challenge of predicting the effects of forest die-off on snow water input, we quantified snow accumulation and ablation at scales ranging from individual trees, through forest stands, to nested small catchments. Our study sites in Northern Colorado and Southern Wyoming are dominated by lodgepole pine, but they include forest stands that are naturally developed, managed and clear-cut with varying mortality from Mountain Pine Beetle (MPB). Our record for winters 2010 and 2011 includes continuous meteorological data and snow depth in plots with varying MPB impact as well as stand- to catchment-scale snow surveys mid-winter and near maximal accumulation. At the plot scale, snow depth sensors in healthy stands recorded greater inputs during storms (21-42% of depth) and greater seasonal accumulation (15-40%) in canopy gaps than under trees, whereas no spatial effects of canopy geometry were observed in stands with heavy mortality. Similar patterns were observed in snow surveys near peak accumulation. At both impacted and thinned sites, spatial variability in snow depth was more closely associated with larger scale topography and changes in stand structure than with canopy cover. The role of aspect in ablation was observed to increase in impacted stands as both shading and wind attenuation decreased. Evidence of wind-controlled snow distribution was found 80-100 meters from exposed stand edges in impacted forest as compared to 10-15 meters in healthy forest. Integrating from the scale of

Land use change impacts on floods at the catchment scale: Challenges and opportunities for future research

Science.gov (United States)

Rogger, M.; Agnoletti, M.; Alaoui, A.; Bathurst, J. C.; Bodner, G.; Borga, M.; Chaplot, V.; Gallart, F.; Glatzel, G.; Hall, J.; Holden, J.; Holko, L.; Horn, R.; Kiss, A.; Kohnová, S.; Leitinger, G.; Lennartz, B.; Parajka, J.; Perdigão, R.; Peth, S.; Plavcová, L.; Quinton, J. N.; Robinson, M.; Salinas, J. L.; Santoro, A.; Szolgay, J.; Tron, S.; van den Akker, J. J. H.; Viglione, A.; Blöschl, G.

2017-07-01

Research gaps in understanding flood changes at the catchment scale caused by changes in forest management, agricultural practices, artificial drainage, and terracing are identified. Potential strategies in addressing these gaps are proposed, such as complex systems approaches to link processes across time scales, long-term experiments on physical-chemical-biological process interactions, and a focus on connectivity and patterns across spatial scales. It is suggested that these strategies will stimulate new research that coherently addresses the issues across hydrology, soil and agricultural sciences, forest engineering, forest ecology, and geomorphology.

Classifying Your Food as Acid, Low-Acid, or Acidified

OpenAIRE

Bacon, Karleigh

2012-01-01

As a food entrepreneur, you should be aware of how ingredients in your product make the food look, feel, and taste; as well as how the ingredients create environments for microorganisms like bacteria, yeast, and molds to survive and grow. This guide will help you classifying your food as acid, low-acid, or acidified.

Effect to groundwater recharge caused by land use change, comparative filed observation in forest and grassland watersheds, Southwestern Japan

Science.gov (United States)

Kudo, K.; Shimada, J.; Tanaka, N.

2011-12-01

City of Kumamoto and their surrounding area are totally supported by the local groundwater as their tap water source, which is quite unique as comparing to the other large cities in Japan because Japanese large cities are mostly supplied by the surface water which is relatively easy to access for their tap water. Because of this, prefecture government of the Kumamoto City has much concern about the sustainable use of groundwater resources for their future generations. In Japan, for the sustainable use of groundwater resources, the forestation in the groundwater recharge area believed to increase the groundwater recharge to the local groundwater aquifer. It is true that the forestation surely works to reduce the direct runoff rate during the flooding period and also works to maintain a bit higher base flow rate during the low flow period than without forestation. However, the effect to the groundwater recharge rate by the forestation is not well understood because of the increase of evapo-transpiration by the tree itself. In order to understand the change of the groundwater recharge rate by the forestation, a paired catchments field observation has been conducted in two adjacent forest (0.088km2) and grassland (0.14km2) watersheds at the western foot of Mt. Aso known as recharge area of major local aquifer of Kumamoto region. The study sites are located at 32°53'N, 130°57'E with elevation ranging from 500 to 800m. The forest watershed consists mainly of around 30 year aged Japanese cypress plantations surrounded by Japanese cedar and mixture forest. The grassland watershed consists mainly of pasture and Japanese silver grass. Both catchments develop on the mountain foot slope consists of the Aso-2 pyroclastic sediments. As for the hydrometric observation system for each catchments, parshall flume runoff weir for the river discharge, meteoric tower for the evapo-transpiration monitoring purpose, and precipitation gage are installed to calculate groundwater recharge

Assessing the drivers of dissolved organic matter export from two contrasting lowland catchments, U.K.

Science.gov (United States)

Yates, Christopher A; Johnes, Penny J; Spencer, Robert G M

2016-11-01

Two lowland catchments in the U.K. were sampled throughout 2010-11 to investigate the dominant controls on dissolved organic matter quantity and composition. The catchments had marked differences in terms of nutrient status, land cover and contrasting lithologies resulting in differences in the dominant flow pathways (groundwater vs. surface water dominated). The Upper Wylye is a chalk stream with a baseflow index of 0.98, draining a catchment dominated by intensive agricultural production. Millersford Brook is a lowland peat catchment with a baseflow index of 0.43, draining a semi-natural catchment with heather moorland and coniferous forest. Samples were collected weekly between October 2010 and September 2011 from eleven sampling locations. Samples were analysed to determine dissolved organic carbon, nitrogen and phosphorus fractions with DOM composition evaluated via the DOC:DON ratio, DOC:DOP ratio, specific UV absorption at 254nm, absorbance ratio (a250:a365) and the spectral slope parameter between 350 and 400nm (S350-400). Significant differences were observed in all determinands between the catchments, over time, and spatially along nutrient enrichment and geoclimatic gradients. Seasonal variation in preferential flow pathways mobilising groundwater-derived DOM were identified as likely controls on the delivery of DOM in the permeable chalk dominated catchment. Steeper S350-400 values and elevated a250:a365 ratios in this catchment suggest material of a lower bulk aromatic C content and molecular weight delivered during the winter months when compared to the summer. DOC:DON ratios were markedly lower in the chalk catchment than the peatland catchment, reflecting the paucity of organic matter within the mineral soils of the chalk landscape, and higher fertiliser application rates. This manuscript highlights that DOM composition varies according to catchment landscape character and hydrological function. Copyright © 2016 The Authors. Published by Elsevier B

Environmental care in agricultural catchments: Toward the communicative catchment

Science.gov (United States)

Martin, Peter

1991-11-01

Substantial land degradation of agricultural catchments in Australia has resulted from the importation of European farming methods and the large-scale clearing of land. Rural communities are now being encouraged by government to take responsibility for environmental care. The importance of community involvement is supported by the view that environmental problems are a function of interactions between people and their environment. It is suggested that the commonly held view that community groups cannot care for their resources is due to inappropriate social institutions rather that any inherent disability in people. The communicative catchment is developed as a vision for environmental care into the future. This concept emerges from a critique of resource management through the catchment metaphors of the reduced, mechanical, and the complex, evolving catchment, which reflect the development of systemic and people-centered approaches to environmental care. The communicative catchment is one where both community and resource managers participate collaboratively in environmental care. A methodology based on action research and systemic thinking (systemic action research) is proposed as a way of moving towards the communicative catchment of the future. Action research is a way of taking action in organizations and communities that is participative and informed by theory, while systemic thinking takes into account the interconnections and relationships between social and natural worlds. The proposed vision, methodology, and practical operating principles stem from involvement in an action research project looking at extension strategies for the implementation of total catchment management in the Hunter Valley, New South Wales.

Validation of a mesoscale hydrological model in a small-scale forested catchment

Czech Academy of Sciences Publication Activity Database

Šípek, Václav; Tesař, Miroslav

2016-01-01

Roč. 47, č. 1 (2016), s. 27-41 ISSN 1998-9563 R&D Projects: GA TA ČR TA02021451 Institutional support: RVO:67985874 Keywords : hydrological modelling * small catchment * soil moisture * subsurface lateral flow * SWIM Subject RIV: DA - Hydrology ; Limnology Impact factor: 1.754, year: 2016

Climate and Landuse Change Impacts on hydrological processes and soil erosion in a dry Mediterranean agro-forested catchment, southern Portugal

Science.gov (United States)

Santos, Juliana; Nunes, João Pedro; Sampaio, Elsa; Moreira, Madalena; Lima, Júlio; Jacinto, Rita; Corte-Real, João

2014-05-01

Climate change is expected to increase aridity in the Mediterranean rim of Europe, due to decreasing rainfall and increasing temperatures. This could lead to impacts on soil erosion, since the lower rainfall could nevertheless become concentrated in higher intensity events during the wet season, while the more arid conditions could reduce vegetation cover, also due to climate-induced land-use changes. In consequence, there is an interest in understanding how climate change will affect the interaction between the timing of extreme rainfall events, hydrological processes, vegetation growth, soil cover and soil erosion. To study this issue, the SWAT eco-hydrological model was applied to Guadalupe, an agro-forested catchment (446 ha) located close to the city of Évora, with a Mediterranean inland climate. The landcover is a mix of dispersed cork oak forests ("montado"), annual crops, and agroforesty regions where the cork oaks are associated with crops or pasture; this land cover is representative of the dry regions of southern Portugal and Spain. The catchment has been instrumented since 2011 with a hydrometric station (water discharge and suspended sediment concentration data) and a soil moisture measurement station. There is also observed data of actual evapotranspiration, LAI and biomass production (in pasture; from 1999 and 2008) and runoff data and sediment yield measured in six 16m2 plots. Water balance, vegetation growth, soil erosion and sediment yield in SWAT was calibrated with this dataset. This work will present the dataset, modeling process, results for impacts of climate and land-use change scenarios for vegetation growth, soil erosion and sediment export, considering the climate and socio-economic scenarios A1b and B1 (based on SRES storylines). Climate scenarios were created by statistical downscaling from Global Circulation Models (GCMs) for the period 2071-2100 (30 years). The reference period was 1971-2000 (30 years). The SWAT model was used to

Acidification policy - control of acidifying emissions in Germany

International Nuclear Information System (INIS)

Schaerer, B.

1992-01-01

Since the mid-eighties total annual acidifying emissions have started to decline in West Germany. There was considerable impact on this positive trend in air pollution by the control of SO 2 and NO x emissions from large boilers, which were reduced by more than 80%. Corresponding control programmes have been established for other groups of sources as well as other pollutants and - with unification - for East Germany. The driving force behind this development was and still is first of all the legal principle of anticipatory action or precaution which means in practical terms 'emission minimization'. This cornerstone of German clean air legislation is the most powerful components of Germany's 'acidification policy', as it requires policy-makers to draw up new or review existing regulations for emission reduction based on requirements according to the state of the art and forces operators to apply the most modern ways and means of operation. This paper describes the system used in Germany to deal with air pollution, the emission minimization strategy, and the actions against acidifying emissions based thereon. In addition, an outlook on what might be necessary to cope with the challenges of a sustainable development concerning acidification is given. 1 ref., 1 fig., 2 tabs

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.

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.

Changing trends of rainfall and sediment fluxes in the Kinta River catchment, Malaysia

Science.gov (United States)

Ismail, W. R.; Hashim, M.

2015-03-01

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.

Influence of landscape heterogeneity on water available to tropical forests in an Amazonian catchment and implications for modeling drought response

Science.gov (United States)

Fang, Yilin; Leung, L. Ruby; Duan, Zhuoran; Wigmosta, Mark S.; Maxwell, Reed M.; Chambers, Jeffrey Q.; Tomasella, Javier

2017-08-01

The Amazon basin has experienced periodic droughts in the past, and intense and frequent droughts are predicted in the future. Landscape heterogeneity could play an important role in how tropical forests respond to drought by influencing water available to plants. Using the one-dimensional ACME Land Model and the three-dimensional ParFlow variably saturated flow model, numerical experiments were performed for a catchment in central Amazon to elucidate processes that influence water available for plant use and provide insights for improving Earth system models. Results from ParFlow show that topography has a dominant influence on groundwater table and runoff through lateral flow. Without any representations of lateral processes, ALM simulates very different seasonal variations in groundwater table and runoff compared to ParFlow even if it is able to reproduce the long-term spatial average groundwater table of ParFlow through simple parameter calibration. In the ParFlow simulations, even in the plateau with much deeper water table depth during the dry season in the drought year of 2005, plant transpiration is not water stressed as the soil saturation is still sufficient for the stomata to be fully open based on the empirical wilting formulation in the models. This finding is insensitive to uncertainty in atmospheric forcing and soil parameters, but the empirical wilting formulation is an important factor that should be addressed using observations and modeling of coupled plant hydraulics-soil hydrology processes in future studies. The results could be applicable to other catchments in the Amazon basin with similar seasonal variability and hydrologic regimes.

Modelling the impacts of European emission and climate change scenarios on acid-sensitive catchments in Finland

Directory of Open Access Journals (Sweden)

M. Posch

2008-03-01

Full Text Available The dynamic hydro-chemical Model of Acidification of Groundwater in Catchments (MAGIC was used to predict the response of 163 Finnish lake catchments to future acidic deposition and climatic change scenarios. Future deposition was assumed to follow current European emission reduction policies and a scenario based on maximum (technologically feasible reductions (MFR. Future climate (temperature and precipitation was derived from the HadAM3 and ECHAM4/OPYC3 general circulation models under two global scenarios of the Intergovernmental Panel on Climate Change (IPCC: A2 and B2. The combinations resulting in the widest range of future changes were used for simulations, i.e., the A2 scenario results from ECHAM4/OPYC3 (highest predicted change and B2 results from HadAM3 (lowest predicted change. Future scenarios for catchment runoff were obtained from the Finnish watershed simulation and forecasting system. The potential influence of future changes in surface water organic carbon concentrations was also explored using simple empirical relationships based on temperature and sulphate deposition. Surprisingly, current emission reduction policies hardly show any future recovery; however, significant chemical recovery of soil and surface water from acidification was predicted under the MFR emission scenario. The direct influence of climate change (temperate and precipitation on recovery was negligible, as runoff hardly changed; greater precipitation is offset by increased evapotranspiration due to higher temperatures. However, two exploratory empirical DOC models indicated that changes in sulphur deposition or temperature could have a confounding influence on the recovery of surface waters from acidification, and that the corresponding increases in DOC concentrations may offset the recovery in pH due to reductions in acidifying depositions.

Effect of an acidifier as replacement for antibiotics on the ...

African Journals Online (AJOL)

An experiment was conducted to determine the influence of an acidifier as an alternative to antibiotics on the performance and gut morphology of broiler chickens. One hundred and eighty (180) 7-day old broiler chicks were randomly assigned to 3 dietary treatments of 4 replicates each. Each replicate had 15 birds.

75 FR 59268 - Draft Guidance for Industry: Acidified Foods; Availability

Science.gov (United States)

2010-09-27

... fermented dairy products, such as yogurt, belong to a separate category that is not relevant to the... the draft guidance, processors of non-acidified foods (e.g., some acid foods or fermented foods) who... regulations. Under the draft guidance, processors of acid foods and fermented foods who conclude that such...

Deposition of acidifying compounds

International Nuclear Information System (INIS)

Fowler, D.; Cape, J.N.; Sutton, M.A.; Mourne, R.; Hargreaves, K.J.; Duyzer, J.H.; Gallagher, M.W.

1992-01-01

Inputs of acidifying compounds to terrestrial ecosystems include deposition of the gases NO 2 , NO, HNO 2 , HNO 3 , NH 3 and SO 2 and the ions NO 3- , NH 4+ , SO 4 2- and H + in precipitation, cloud droplets and particles. Recent research has identified particular ecosystems and regions in which terrestrial effects are closely linked with specific deposition processes. This review paper identifies areas in which important developments have occurred during the last five years and attempts to show which aspects of the subject are most important for policy makers. Amongst the conclusions drawn, the authors advise that current uncertainties in estimates of S and N inputs by dry deposition should be incorporated in critical load calculations, and that, in regions dominated by wet deposition, spatial resolution of total inputs should be improved to match the current scales of information on landscape sensitivity to acidic inputs. 44 refs., 9 figs

Sphagnum mosses as a microhabitat for invertebrates in acidified lakes and the colour adaptation and substrate preference in Leucorrhinia dubia (Odonata, Anisoptera)

Energy Technology Data Exchange (ETDEWEB)

Henrikson, B.-I. (Dept. of Zoology, Sect. of Animal Ecology, Univ. of Goeteborg, Goeteborg (Sweden))

1993-01-01

The increase of peat mosses, Sphagnum spp., in acidified lakes leads to a changed microhabitat structure for benthic invertebrates. The importance of this change was investigated for some benthic invertebrates. Comparisons between quantitative samples of Sphagnum and debris within the acidified Lake Stora Haestevatten, in the Lake Gaardsjoen catchment of SW Sweden, showed significantly higher abundances of Chironomidae, Ceratopogonidae, Odonata, Trichoptera, Cladocera and Argyroneta aquatica (Araneae) in Sphagnum. For chironomidae and Cladocera the differences were tenfold. Special reference was made to the libellulid Leucorrhinia dubia which is common in acid lakes. In a laboratory test, late instar larvae of L. dubia were shown to change colour to correspond to the brown and green colour of Sphagnum. This result was completed with a field test where larvae of L. dubia were significantly more common in Sphagnum of the same colour as the larvae. The ability to change colour may have an adaptive value when coexisting with visual predators. Small larvae were more prevalent in Sphagnum and they also showed a preference for this substrate in the laboratory test. Laboratory tests showed mediumsized larvae preferred Sphagnum. Larvae of L. dubia were more successful as predators on Asellus aquaticus in Sphagnum substrate than in debris in the laboratory test. Laboratory predation tests with notonecta glauca, Corixa dentipes, Acilius sulcatus, Hyphydrus ovatus and L. dubia showed that they could all feed on larvae of L. dubia. The complex habitat structure of Sphagnum is probably the reason for the high abundance of invertebrates since it may serve as both shelter against predation and as foraging sites. it is probably important as a key habitat for young instars of, for example, L. dubia. In lakes with large Sphagnum mats, L. dubia can coexist with fish. The expansion of Sphagnum due to acidification will probably benefit many acid-tolerant invertebrate species. (au)

Hydrological Modeling in Data-Scarce Catchments: The Kilombero Floodplain in Tanzania

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Kristian Näschen

2018-05-01

Full Text Available Deterioration of upland soils, demographic growth, and climate change all lead to an increased utilization of wetlands in East Africa. This considerable pressure on wetland resources results in trade-offs between those resources and their related ecosystem services. Furthermore, relationships between catchment attributes and available wetland water resources are one of the key drivers that might lead to wetland degradation. To investigate the impacts of these developments on catchment-wetland water resources, the Soil and Water Assessment Tool (SWAT was applied to the Kilombero Catchment in Tanzania, which is like many other East African catchments, as it is characterized by overall data scarcity. Due to the lack of recent discharge data, the model was calibrated for the period from 1958–1965 (R2 = 0.86, NSE = 0.85, KGE = 0.93 and validated from 1966–1970 (R2 = 0.80, NSE = 0.80, KGE = 0.89 with the sequential uncertainty fitting algorithm (SUFI-2 on a daily resolution. Results show the dependency of the wetland on baseflow contribution from the enclosing catchment, especially in dry season. Main contributions with regard to overall water yield arise from the northern mountains and the southeastern highlands, which are characterized by steep slopes and a high share of forest and savanna vegetation, respectively. Simulations of land use change effects, generated with Landsat images from the 1970s up to 2014, show severe shifts in the water balance components on the subcatchment scale due to anthropogenic activities. Sustainable management of the investigated catchment should therefore account for the catchment–wetland interaction concerning water resources, with a special emphasis on groundwater fluxes to ensure future food production as well as the preservation of the wetland ecosystem.

Stormflow influence on nutrient dynamics in micro-catchments under contrasting land use in the Cerrado and Amazon Biomes, Brazil

Science.gov (United States)

Edelmann, Katharina; Nóbrega, Rodolfo L. B.; Gerold, Gerhard

2017-04-01

The Amazon and Cerrado biomes in Brazil have been under intense land-use change during the past few decades. The conversion of native vegetation to pastures and croplands has caused impacts on hydrological processes in these biomes, resulting in increased streamflow and nutrient fluxes. Our aim was to compare the nutrient dynamics during stormflow events in two pairs of adjacent micro-catchments with similar physical characteristics under contrasting land use, i.e. native vegetation (rainforest or cerrado) and pasture. One pair of catchments was located in the Amazon and the other in the Cerrado, both on the Amazon Agricultural Frontier in the Brazilian states of Mato Grosso and Pará. We collected hydrological and hydrochemical data on 50 stormflow events on a sub-hourly resolution during the wet seasons of 2013 and 2014. We compared the dynamics of total inorganic carbon (TIC), total organic carbon (TOC), dissolved organic carbon (DOC), nitrate (NO3), calcium (Ca), potassium (K), and magnesium (Mg) in different hydrograph parts, i.e. rising limb, peak and recession limb, between the catchments within the same biome. For the Cerrado biome, our findings show that the nutrient concentrations in the stormflows were higher in the pasture catchment than in the cerrado catchment. In the Amazon biome, we found an inverse relationship with higher concentrations in the forest catchment than in the pasture catchment, except for TIC and K. Most nutrients in the cerrado catchment had the highest concentrations in the rising limb. Mg, however, reached highest concentrations during peak discharge, and lowest in the recession limb. In the adjacent pasture catchment, in contrast, the highest nutrient concentrations were observed during the peak discharge (TIC, TOC, Ca) or the recession limb (DOC, NO3, K, Mg) with lowest in the rising limb, except for NO3, which showed the lowest concentrations during peak discharge. In the Amazon forest catchment, the peak discharge showed the

Avoiding Implementation Failure in Catchment Landscapes: A Case Study in Governance of the Great Barrier Reef.

Science.gov (United States)

Dale, Allan P; Vella, Karen; Gooch, Margaret; Potts, Ruth; Pressey, Robert L; Brodie, Jon; Eberhard, Rachel

2017-10-04

Water quality outcomes affecting Australia's Great Barrier Reef (GBR) are governed by multi-level and multi-party decision-making that influences forested and agricultural landscapes. With international concern about the GBR's declining ecological health, this paper identifies and focuses on implementation failure (primarily at catchment scale) as a systemic risk within the overall GBR governance system. There has been limited integrated analysis of the full suite of governance subdomains that often envelop defined policies, programs and delivery activities that influence water quality in the GBR. We consider how the implementation of separate purpose-specific policies and programs at catchment scale operate against well-known, robust design concepts for integrated catchment governance. We find design concerns within ten important governance subdomains that operate within GBR catchments. At a whole-of-GBR scale, we find a weak policy focus on strengthening these delivery-oriented subdomains and on effort integration across these subdomains within catchments. These governance problems when combined may contribute to failure in the implementation of major national, state and local government policies focused on improving water quality in the GBR, a lesson relevant to landscapes globally.

Intracellular pH homeostasis plays a role in the tolerance ofDebaryomyces hansenii and Candida zeylanoides to acidified nitrite

DEFF Research Database (Denmark)

Mortensen, Henrik Dam; Jacobsen, Thomas; Koch, Anette Granly

2008-01-01

. hansenii at an external pH (pHex) value of 4.5 butdid not at pHex 5.5. These results indicate that nitrous acid as such plays an important role in the antifungal effect of acidified nitrite. Furthermore, both yeast species experienced severe growth inhibition and a pHi decrease at pHex 4.5, suggesting...... that at least some of the antifungal effects of acidified nitrite may be due to intracellular acidification. For C. zeylanoides, this phenomenon could be explained in part by the uncoupling effect of energy generation from growth. Debaryomyces hansenii was more tolerant to acidified nitrite at pHex 5.5 than C....... zeylanoides, as determined by the rate of growth initiation. In combination with the fact that D. hansenii was able to maintain pHi homeostasis at pHex 5.5 but C. zeylanoides was not, our results suggest that the ability to maintain pHi homeostasis plays a role in the acidified-nitrite tolerance of D...

Water migration of macroelements in coniferous-broad-leaved forests of Sikhote-Alin

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N. K. Kozhevnikova

2017-06-01

Full Text Available In the paper, the natural water chemical composition spatial variability studies results in the mountain forest catchment are presented. It’s shown that the catchment biotic components’ impact upon water chemical composition is detected even at input as atmospheric precipitation. The input fluxes are acid, sulfate ones with high ratio of hydrogen, potassium and dissolved organic matter. Diversity of ecotopic conditions determines the further transformation of natural water chemical composition. The role of tree crowns in the transformation increases while the crown closure and stands’ age increase. According to macrocomponents transformation and rain acidity neutralization, forest associations form the sequence: mixed > coniferous > young deciduous ones. Dissolved organic carbon (DOC, potassium and calcium become the main components of water chemical composition, while sulfates dominate among anions. For vegetation period, 9–11 kg/ha of sulfates come below tree crown. Biogenic elements transport is gradually limited in soil profile at the migration stage. Sulfate-potassium composition throughfall in spruce-fir and secondary forests community transforms into sulfate-sodium-calcium. Hydrocarbonates predominate in soil water in broad-leaved-pine type of forest, and potassium output decreases 10 times. Geochemical type of river water keeps features of chemical composition of soil drained by river section. Negligible output of sulfates, hydrocarbonates and calcium from ecosystem is established for the headwaters. Negative balance of hydrocarbonates and calcium is compensated by significant input of these components with throughfall at catchments with predominantly pine-broad-leaved forest types.

A catchment-scale carbon and greenhouse gas budget of a subarctic landscape

DEFF Research Database (Denmark)

Christensen, Torben R; Johansson, Torbjörn; Olsrud, Maria

2007-01-01

forest, and mires, lakes and alpine ecosystems. The magnitudes of atmospheric exchange of carbon in the form of the GHGs, CO2 and CH4 in these various ecosystems differ significantly, ranging from little or no flux in barren ecosystems over a small CO2 sink function and low rates of CH4 exchange...... in the heaths to significant CO2 uptake in the forests and also large emissions of CH4 from the mires and small lakes. The overall catchment budget, given the size distribution of the individual ecosystem types and a first approximation of run-off as dissolved organic carbon, reveals a landscape currently...

Hydroeconomic DSS for optimal hydrology-oriented forest management in semiarid areas

Science.gov (United States)

Garcia-Prats, A.; del Campo, A.; Pulido-Velazquez, M.

2016-12-01

In semiarid regions like the Mediterranean, managing the upper-catchment forests for water provision goals (hydrology-oriented silviculture) offers a strategy to increase the resilience of catchments to droughts and lower precipitation and higher evapotranspiration due to climate change. Understanding the effects of forest management on vegetation water use and groundwater recharge is particularly important in those regions. Despite the essential role that forests play in the water cycle on the provision of water resources, this contribution is often neither quantified nor explicitly valued. The aim of this work is to develop a novel decision support system (DSS) based on hydro-economic modelling, for assessing and designing the optimal integrated forest and water management for forested catchments. Hydro-economic modelling may support the design of economically efficient strategies integrating the hydrologic, engineering, environmental and economic aspects of water resources systems within a coherent framework. The optimization model explicitly integrates changes in water yield (increase n groundwater recharge) induced by the management of forest density, and the value of the additional water provided to the system. This latter component could serve as an indicator for the design of a "payment for environmental services" scheme in which groundwater beneficiaries could contribute towards funding and promoting efficient forest management operations. Besides, revenues from timber logging are also articulated in the modelling. The case study was an Aleppo pine forest in south-western Valencia province (Spain), using a typical 100-year rotation horizon. The model determines the optimal schedule of thinning interventions in the stands in order to maximize the total net benefits in the system (timber and water). Canopy cover and biomass evolution over time were simulated using growth and yield allometric equations specific for the species in Mediterranean conditions

A soil-landscape framework for understanding spatial and temporal variability in biogeochemical processes in catchments

Science.gov (United States)

McGuire, K. J.; Bailey, S. W.; Ross, D. S.

2017-12-01

Heterogeneity in biophysical properties within catchments challenges how we quantify and characterize biogeochemical processes and interpret catchment outputs. Interactions between the spatiotemporal variability of hydrological states and fluxes and soil development can spatially structure catchments, leading to a framework for understanding patterns in biogeochemical processes. In an upland, glaciated landscape at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, USA, we are embracing the structure and organization of soils to understand the spatial relations between runoff production zones, distinct soil-biogeochemical environments, and solute retention and release. This presentation will use observations from the HBEF to demonstrate that a soil-landscape framework is essential in understanding the spatial and temporal variability of biogeochemical processes in this catchment. Specific examples will include how laterally developed soils reveal the location of active runoff production zones and lead to gradients in primary mineral dissolution and the distribution of weathering products along hillslopes. Soil development patterns also highlight potential carbon and nitrogen cycling hotspots, differentiate acidic conditions, and affect the regulation of surface water quality. Overall, this work demonstrates the importance of understanding the landscape-level structural organization of soils in characterizing the variation and extent of biogeochemical processes that occur in catchments.

Export of nitrogen from catchments: A worldwide analysis

International Nuclear Information System (INIS)

Alvarez-Cobelas, M.; Angeler, D.G.; Sanchez-Carrillo, S.

2008-01-01

This study reviews nitrogen export rates from 946 rivers of the world to determine the influence of quantitative (runoff, rainfall, inhabitant density, catchment area, percentage of land use cover, airborne deposition, fertilizer input) and qualitative (dominant type of forest, occurrence of stagnant waterbodies, dominant land use, occurrence of point sources, runoff type) environmental factors on nitrogen fluxes. All fractions (total, nitrate, ammonia, dissolved organic and particulate organic) of nitrogen export showed a left-skewed distribution, which suggests a relatively pristine condition for most systems. Total nitrogen export showed the highest variability whereas total organic nitrogen export comprised the dominant fraction of export. Nitrogen export rates were only weakly explained by our qualitative and quantitative environmental variables. Our study suggests that the consideration of spatial and temporal scales is important for predicting nitrogen export rates using simple and easy-to-get environmental variables. Regionally based modelling approaches prove more useful than global-scale analyses. - Spatial and temporal scales are important determinants for nitrogen export from catchments and emphasis should be put on regional approaches

Characteristics of Sediment Transportation in Two Contrasting Oak Forested Watersheds in the Lesser Central Himalaya, India

Science.gov (United States)

Qazi, N. U. Q.; Bruijnzeel, S., Sr.; Rai, S. P., Sr.

2015-12-01

Sediment transfer from mountainous areas to lowland areas is one of the most important geomorphological processes globally with the bulk of the sediment yield from such areas typically deriving from mass wastage processes. This study presents monthly, seasonal and annual variations in sediment transport (both suspended load and bedload) as well as dissolved loads over three consecutive water years (2008-2011) for two small forested watersheds with contrasting levels of forest disturbance in the Lesser Himalaya of Northwest India. Seasonal and annual suspended sediment yields were strongly influenced by amounts of rainfall and streamflow and showed a 10-63 fold range between wet and dry years. Of the annual load, some 93% was produced on average during the monsoon season (June-September). Sediment production by the disturbed forest catchment was 1.9-fold (suspended sediment) to 5.9-fold (bedload) higher than that for the well-stocked forest catchment. By contrast, dissolved loads varied much less between years, seasons (although minimal during the dry summer season), and degree of forest disturbance. Total mechanical denudation rates were 1.6 times and 4.6 times larger than chemical denudation rates for the little disturbed and the heavily disturbed forest catchment, respectively whereas overall denudation rates were estimated at 0.69 and 1.04 mm per 1000 years, respectively.

A new perspective on catchment storage gained from a nested catchment experiment in Luxembourg (Europe)

Science.gov (United States)

Pfister, Laurent; Klaus, Julian; Hissler, Christophe; François Iffly, Jean; Gourdol, Laurent; Martinez-Carreras, Nuria; McDonnell, Jeffrey J.

2014-05-01

Recent hydrological process research focussed on how much water a catchment can store and how these catchments store and release water. Storage can be a valuable metric for catchment description, inter-comparison, and classification. Further storage controls catchment mixing, non-linearities in rainfall-runoff transformation and eco-hydrological processes. Various methods exist to determine catchment storage (e.g. natural tracer, soil moisture and groundwater data, hydrological models). Today it remains unclear what parts of the catchment storage are measured with the different models. Here we present a new hydrometric approach to answer the question how much water a catchment can store. We tested our approach in a dense hydro-climatological monitoring network that encompasses 16 recording streamgauges and 21 pluviographs in the Alzette River basin in Luxembourg (Europe). Catchment scales are ranging from 0.47 to 285 km2 and they have clean- and mixed combinations of distinct geologies ranging from schists to marls, sandstone, dolomite and limestone. Previous investigations in the area of interest have shown that geology largely controls winter runoff coefficients. Here, we focus at how catchment geology is ultimately affecting catchment storage. We used the approach of Sayama et al. (2011) to compute catchment dynamic storage changes for each winter season over the period 2002-2012 (based on precipitation as input; discharge and evapotranspiration as output). We determined dynamic storage changes for each winter semester (October to March) in all 16 catchments over the period 2002-2012. At the beginning of each hydrological winter season, all catchments showed similar trends in storage change. A few weeks into the winter season, catchments with lowest permeability (e.g. marls) started to plateau. The highest storage values were reached several months later in the season in catchments dominated by permeable substrate (e.g. sandstone). For most catchments, we found

Susceptibility of Shallow Landslide in Fraser Hill Catchment, Pahang Malaysia

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Wan Nor Azmin Sulaiman

2010-01-01

Full Text Available In tropical areas especially during monsoon seasons intense precipitation is the main caused that trigger the natural shallow landslide phenomena. This phenomenon can be disastrous and widespread in occurrence even in undisturbed forested catchment. In this paper, an attempt has been made to evaluate the susceptibility of natural hill slopes to failure for a popular hill resort area, the Fraser Hill Catchment under different rainfall regimes and soil thickness. A Digital Elevation Model (DEM was prepared for the 8.2 km2 catchment. A GIS based deterministic model was then applied to predict the spatial landslide occurrence within catchment. Model input parameters include bulk density, friction angle, cohesion and hydraulic conductivity were gathered through in situ and lab analysis as well as from previous soil analysis records. Landslides locations were recorded using GPS as well as previous air photos and satellite imagery to establish landslide source areas inventory. The landslide susceptibility map was produced under different precipitation event’s simulation to see the effects of precipitation to stability of the hill slopes of the catchment. The results were categorized into naturally unstable (Defended, Upper Threshold, Lower Threshold, marginal instability (Quasi Stable and stable area (Moderately Stable and Stable. Results of the simulation indicated notable change in precipitation effect on Defended area is between 10mm to 40mm range in a single storm event. However, when storm event is exceeded 120mm, the result on Defended area produced by the model tends to be constant further on. For area categorized as naturally unstable (Factor of Safety, SF<1, with 110 mm of precipitation in a single storm event and soil depth at 2 meters and 4 meters could affect 69.51% and 69.88% respectively of the catchment area fall under that class. In addition, the model was able to detect 4% more of the landslide inventory under shallower soil depth of

Influence of acidified acidity to uranium bioleaching

International Nuclear Information System (INIS)

Li Jiang; Liu Yajie; Zheng Zhihong; Yuan Baohua; Shen Chuan; Shi Weijun

2012-01-01

The relationship between the acidified acidity and the acid consumption and uranium leaching rate in the process of uranium bioleaching is investigated. Results indicate that higher uranium leaching rate is obtained when the relatively high acidity was applied at beginning. For different minerals, although the original acidity should be different, lower original acidity was not better for shortening leaching period and improving uranium leaching rate. It confirms 30-40 g/L sulfuric acid as the original acidity was more suitable and more than 30 g/ L should be applied if the mineral particle sizes were larger. (authors)

Administration of acidified drinking water to finishing pigs in order to prevent Salmonella infections.

Science.gov (United States)

van der Wolf, P J; van Schie, F W; Elbers, A R; Engel, B; van der Heijden, H M; Hunneman, W A; Tielen, M J

2001-07-01

The aim of the study was to test whether acidified drinking water, with two millilitres of an acid mixture per litre, was able to reduce the number of Salmonella infections in finishing pig herds. In each compartment, half of the pens were supplied with acidified water and the other pens served as negative control. In three herds the required dose was not applied to the pigs as a result of various practical problems. In another herd, all pigs remained seronegative throughout the study. Analysis of the remaining three herds showed a large and significant treatment effect in one herd (Pdrinking nipples as a result of fungal growth in the pipelines.

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?

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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.

Canopy structure and topography effects on snow distribution at a catchment scale: Application of multivariate approaches

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Jenicek Michal

2018-03-01

Full Text Available The knowledge of snowpack distribution at a catchment scale is important to predict the snowmelt runoff. The objective of this study is to select and quantify the most important factors governing the snowpack distribution, with special interest in the role of different canopy structure. We applied a simple distributed sampling design with measurement of snow depth and snow water equivalent (SWE at a catchment scale. We selected eleven predictors related to character of specific localities (such as elevation, slope orientation and leaf area index and to winter meteorological conditions (such as irradiance, sum of positive air temperature and sum of new snow depth. The forest canopy structure was described using parameters calculated from hemispherical photographs. A degree-day approach was used to calculate melt factors. Principal component analysis, cluster analysis and Spearman rank correlation were applied to reduce the number of predictors and to analyze measured data. The SWE in forest sites was by 40% lower than in open areas, but this value depended on the canopy structure. The snow ablation in large openings was on average almost two times faster compared to forest sites. The snow ablation in the forest was by 18% faster after forest defoliation (due to the bark beetle. The results from multivariate analyses showed that the leaf area index was a better predictor to explain the SWE distribution during accumulation period, while irradiance was better predictor during snowmelt period. Despite some uncertainty, parameters derived from hemispherical photographs may replace measured incoming solar radiation if this meteorological variable is not available.

Community structures and activity of denitrifying microbes in a forested catchment in central Japan: survey using nitrite reductase genes

Science.gov (United States)

Ohte, N.; Aoki, M.; Katsuyama, C.; Suwa, Y.; Tange, T.

2012-12-01

To elucidate the mechanisms of denitrification processes in the forested catchment, microbial ecological approaches have been applied in an experimental watershed that has previously investigated its hydrological processes. The study catchment is located in the Chiba prefecture in central Japan under the temperate Asian monsoon climate. Potential activities of denitrification of soil samples were measured by incubation experiments under anoxic condition associated with Na15NO3 addition. Existence and variety of microbes having nitrite reductase genes were investigated by PCR amplification, cloning and sequencings of nirK and nirS fragments after DNA extraction. Contrary to our early expectation that the potential denitrification activity was higher at deeper soil horizon with consistent groundwater residence than that in the surface soil, denitrification potential was higher in shallower soil horizons than deeper soils. This suggested that the deficiency of NO3- as a respiratory substrate for denitrifier occurred in deeper soils especially in the summer. However, high denitrification activity and presence of microbes having nirK and nirS in surface soils usually under aerobic condition was explainable by the fact that the majority of denitrifying bacteria have been recognized as a facultative anaerobic bacterium. This also suggests the possibility of that denitrification occurs even in the surface soils if the wet condition is provided by rainwater during and after a storm event. Community structures of microbes having nirK were different between near surface and deeper soil horizons, and ones having nirS was different between saturated zone (under groundwater table) and unsaturated soil horizons. These imply that microbial communities with nisK are sensitive to the concentration of soil organic matters and ones with nirS is sensitive to soil moisture contents.

Sediment sources in the Upper Severn catchment: a fingerprinting approach

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A. L. Collins

1997-01-01

Full Text Available Suspended sediment sources in the Upper Severn catchment are quantified using a composite fingerprinting technique combining statistically-verified signatures with a multivariate mixing model. Composite fingerprints are developed from a suite of diagnostic properties comprising trace metal (Fe, Mn, AI, heavy metal (Cu, Zn, Pb, Cr, Co, Ni, base cation (Na, Mg, Ca, K, organic (C, N, radiometric (137Cs, 210Pb, and other (total P determinands. A numerical mixing model, to compare the fingerprints of contemporary catchment source materials with those of fluvial suspended sediment in transit and those of recent overbank floodplain deposits, provides a means of quantifying present and past sediment sources respectively. Sources are classified in terms of eroding surface soils under different land uses and channel banks. Eroding surface soils are the most important source of the contemporary suspended sediment loads sampled at the Institute of Hydrology flow gauging stations at Plynlimon and at Abermule. The erosion of forest soils, associated with the autumn and winter commercial activities of the Forestry Commission, is particularly evident. Reconstruction of sediment provenance over the recent past using a sediment core from the active river floodpiain at Abermule, in conjunction with a 137Cs chronology, demonstrates the significance of recent phases of afforestation and deforestation for accelerated catchment soil erosion.

How runoff begins (and ends): characterizing hydrologic response at the catchment scale

Science.gov (United States)

Mirus, Benjamin B.; Loague, Keith

2013-01-01

Improved understanding of the complex dynamics associated with spatially and temporally variable runoff response is needed to better understand the hydrology component of interdisciplinary problems. The objective of this study was to quantitatively characterize the environmental controls on runoff generation for the range of different streamflow-generation mechanisms illustrated in the classic Dunne diagram. The comprehensive physics-based model of coupled surface-subsurface flow, InHM, is employed in a heuristic mode. InHM has been employed previously to successfully simulate the observed hydrologic response at four diverse, well-characterized catchments, which provides the foundation for this study. The C3 and CB catchments are located within steep, forested terrain; the TW and R5 catchments are located in gently sloping rangeland. The InHM boundary-value problems for these four catchments provide the corner-stones for alternative simulation scenarios designed to address the question of how runoff begins (and ends). Simulated rainfall-runoff events are used to systematically explore the impact of soil-hydraulic properties and rainfall characteristics. This approach facilitates quantitative analysis of both integrated and distributed hydrologic responses at high-spatial and temporal resolution over the wide range of environmental conditions represented by the four catchments. The results from 140 unique simulation scenarios illustrate how rainfall intensity/depth, subsurface permeability contrasts, characteristic curve shapes, and topography provide important controls on the hydrologic-response dynamics. The processes by which runoff begins (and ends) are shown, in large part, to be defined by the relative rates of rainfall, infiltration, lateral flow convergence, and storage dynamics within the variably saturated soil layers.

Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

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Sarah E Pabian

Full Text Available Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

Impacts of elevated carbon dioxide and temperature on a boreal forest ecosystem (CLIMEX project)

DEFF Research Database (Denmark)

Breemen, N. van; Jenkins, A.; Wright, R.F.

1998-01-01

To evaluate the effects of climate change on boreal forest ecosystems, both atmospheric CO2 (to 560 ppmv) and air temperature (by 3 degrees-5 degrees C above ambient) were increased at a forested headwater catchment in southern Norway. The entire catchment (860 m(2)) is enclosed within...... and the growing season has been prolonged relative to the control area. This has helped to sustain an increase in plant growth relative to the control and has also promoted increased N export in stream water. Photosynthetic capacity and carbon-nitrogen ratio of new leaves of most plant species did not change...

Runoff Trends Analysis and Future Projections of Hydrological Patterns in Small Forested Catchments

Czech Academy of Sciences Publication Activity Database

Lamačová, Anna; Hruška, Jakub; Krám, Pavel; Stuchlik, E.; Farda, Aleš; Chuman, T.; Fottová, Daniela

2014-01-01

Roč. 9, č. 4 (2014), s. 169-181 ISSN 1801-5395 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : climate change * flow pattern * headwater catchments * hydrological modelling Subject RIV: EH - Ecology, Behaviour Impact factor: 0.659, year: 2014

Storylines of combined land use and climatic drivers and their hydrological impacts in an alpine catchment (Brixental/Austria)

Science.gov (United States)

Strasser, Ulrich; Förster, Kristian; Meissl, Gertraud; Marke, Thomas; Schermer, Markus; Stotten, Rike; Formayer, Herbert; Themessl, Matthias

2017-04-01

We present a numerical modelling experiment with storylines of coupled land use and climate evolution as input in the physically-based, distributed water balance model WaSiM. The aim is to quantify the effects of these two framing components on the future water cycle. The test site for the simulations is the catchment of the Brixentaler Ache in Tyrol/Austria (47.5°N, 322 km2). The climatic background is defined by simulations for the A1B and RCP 8.5 emission scenarios until 2050. These two climate projections were combined with three future land use developments for forest management, developed in an inter- and transdisciplinary assessment with local actors using plausible and consisent projections for forest management, policy, social cooperation, tourism and economy: (i) Ecological adaptation: The forest management consequently applies the political guidelines, and the forest cover is dominated by an ecological, place-adapted mixed cultivation with a harmonious age structure. (ii) Economical overexploitation and wildness: The increase in efficiency, cost reduction and short term results are in focus of the forest management. (iii) Withdrawal and wildness: Cultivation in general is decreasing, and the forest becomes vulnerable against natural hazards. A new module for snow-canopy interaction simulation, providing explicit rates of intercepted and sublimated snow from the trees and stems of the different forest stands, has been implemented in WaSiM. The new version of the model is used to model the coupled future climate/land use storylines for the Brixental. Results show the effects of climate change and land use on the water balance and streamflow in the catchment.

Hydrologic response to and recovery from differing silvicultural systems in a deciduous forest landscape with seasonal snow cover

Science.gov (United States)

Buttle, J. M.; Beall, F. D.; Webster, K. L.; Hazlett, P. W.; Creed, I. F.; Semkin, R. G.; Jeffries, D. S.

2018-02-01

Hydrological consequences of alternative harvesting strategies in deciduous forest landscapes with seasonal snow cover have received relatively little attention. Most forest harvesting experiments in landscapes with seasonal snow cover have focused on clearcutting in coniferous forests. Few have examined alternative strategies such as selection or shelterwood cutting in deciduous stands whose hydrologic responses to harvesting may differ from those of conifers. This study presents results from a 31-year examination of hydrological response to and recovery from alternative harvesting strategies in a deciduous forest landscape with seasonal snow cover in central Ontario, Canada. A quantitative means of assessing hydrologic recovery to harvesting is also developed. Clearcutting resulted in increased water year (WY) runoff. This was accompanied by increased runoff in all seasons, with greatest relative increases in Summer. Direct runoff and baseflow from treatment catchments generally increased following harvesting, although annual peak streamflow did not. Largest increases in WY runoff and seasonal runoff as well as direct runoff and baseflow generally occurred in the selection harvest catchment, likely as a result of interception of hillslope runoff by a forest access road and redirection to the stream channel. Hydrologic recovery appeared to begin towards the end of the experimental period for several streamflow metrics but was incomplete for all harvesting strategies 15 years after harvesting. Geochemical tracing indicated that harvesting enhanced the relative importance of surface and near-surface water pathways on catchment slopes for all treatments, with the clearcut catchment showing the most pronounced and prolonged response. Such insights into water partitioning between flow pathways may assist assessments of the ecological and biogeochemical consequences of forest disturbance.

Predicting long-term recovery of a strongly acidified stream using MAGIC and climate models (Litavka, Czech Republic

Directory of Open Access Journals (Sweden)

D. W. Hardekopf

2008-03-01

Full Text Available Two branches forming the headwaters of a stream in the Czech Republic were studied. Both streams have similar catchment characteristics and historical deposition; however one is rain-fed and strongly affected by acid atmospheric deposition, the other spring-fed and only moderately acidified. The MAGIC model was used to reconstruct past stream water and soil chemistry of the rain-fed branch, and predict future recovery up to 2050 under current proposed emissions levels. A future increase in air temperature calculated by a regional climate model was then used to derive climate-related scenarios to test possible factors affecting chemical recovery up to 2100. Macroinvertebrates were sampled from both branches, and differences in stream chemistry were reflected in the community structures. According to modelled forecasts, recovery of the rain-fed branch will be gradual and limited, and continued high levels of sulphate release from the soils will continue to dominate stream water chemistry, while scenarios related to a predicted increase in temperature will have little impact. The likelihood of colonization of species from the spring-fed branch was evaluated considering the predicted extent of chemical recovery. The results suggest that the possibility of colonization of species from the spring-fed branch to the rain-fed will be limited to only the acid-tolerant stonefly, caddisfly and dipteran taxa in the modelled period.

Forest blowdown and lake acidification

International Nuclear Information System (INIS)

Dobson, J.E.; Rush, R.M.; Peplies, R.W.

1990-01-01

The authors examine the role of forest blowdown in lake acidification. The approach combines geographic information systems (GIS) and digital remote sensing with traditional field methods. The methods of analysis consist of direct observation, interpretation of satellite imagery and aerial photographs, and statistical comparison of two geographical distributions-one representing forest blow-down and another representing lake chemistry. Spatial and temporal associations between surface water pH and landscape disturbance are strong and consistent in the Adirondack Mountains of New York. In 43 Adirondack Mountain watersheds, lake pH is associated with the percentage of the watershed area blown down and with hydrogen ion deposition (Spearman rank correlation coefficients of -0.67 and -0.73, respectively). Evidence of a temporal association is found at Big Moose Lake and Jerseyfield Lake in New York and the Lygners Vider Plateau of Sweden. They conclude that forest blowdown facilities the acidification of some lakes by altering hydrologic pathways so that waters (previously acidified by acid deposition and/or other sources) do not experience the neutralization normally available through contact with subsurface soils and bedrock. Increased pipeflow is suggested as a mechanism that may link the biogeochemical impacts of forest blowdown to lake chemistry

Simulating the effect of vegetation cover on the sediment yield of mediterranean catchments using SHETRAN

Science.gov (United States)

Lukey, B. T.; Sheffield, J.; Bathurst, J. C.; Lavabre, J.; Mathys, N.; Martin, C.

1995-08-01

The sediment yield of two catchments in southern France was modelled using the newly developed sediment code of SHETRAN. A fire in August 1990 denuded the Rimbaud catchment, providing an opportunity to study the effect of vegetation cover on sediment yield by running the model for both pre-and post-fire cases. Model output is in the form of upper and lower bounds on sediment discharge, reflecting the uncertainty in the erodibility of the soil. The results are encouraging since measured sediment discharge falls largely between the predicted bounds, and simulated sediment yield is dramatically lower for the catchment before the fire which matches observation. SHETRAN is also applied to the Laval catchment, which is subject to Badlands gulley erosion. Again using the principle of generating upper and lower bounds on sediment discharge, the model is shown to be capable of predicting the bulk sediment discharge over periods of months. To simulate the effect of reforestation, the model is run with vegetation cover equivalent to a neighbouring fully forested basin. The results obtained indicate that SHETRAN provides a powerful tool for predicting the impact of environmental change and land management on sediment yield.

Controls on inorganic nitrogen leaching from Finnish catchments assessed using a sensitivity and uncertainty analysis of the INCA-N model

Energy Technology Data Exchange (ETDEWEB)

Rankinen, K.; Granlund, K. [Finnish Environmental Inst., Helsinki (Finland); Futter, M. N. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden)

2013-11-01

The semi-distributed, dynamic INCA-N model was used to simulate the behaviour of dissolved inorganic nitrogen (DIN) in two Finnish research catchments. Parameter sensitivity and model structural uncertainty were analysed using generalized sensitivity analysis. The Mustajoki catchment is a forested upstream catchment, while the Savijoki catchment represents intensively cultivated lowlands. In general, there were more influential parameters in Savijoki than Mustajoki. Model results were sensitive to N-transformation rates, vegetation dynamics, and soil and river hydrology. Values of the sensitive parameters were based on long-term measurements covering both warm and cold years. The highest measured DIN concentrations fell between minimum and maximum values estimated during the uncertainty analysis. The lowest measured concentrations fell outside these bounds, suggesting that some retention processes may be missing from the current model structure. The lowest concentrations occurred mainly during low flow periods; so effects on total loads were small. (orig.)

Effects of land use change on streamflow and stream water quality of a coastal catchment

CSIR Research Space (South Africa)

Petersen, Chantel R

2017-01-01

Full Text Available Main stream length (km) 28.4 19.46 Main stream slope (%) 3.4 2.6 Drainage density (km/km2) 2.51 3.59 Length of overland flow (km) 0.19 0.139   Figure 1    Figure 1 Catchments of the Touws and Duiwe Rivers 141 http://dx.doi.org/10.4314/wsa.v43i1... catchment throughout the period examined (Fig. 2a, Table 3), as the natural forest areas were formally protected from the 142 http://dx.doi.org/10.4314/wsa.v43i1.16 Available on website http://www.wrc.org.za ISSN 1816-7950 (Online) = Water SA Vol. 43 No. 1...

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.

Diatoms as a fingerprint of sub-catchment contributions to meso-scale catchment runoff

Science.gov (United States)

Klaus, Julian; Wetzel, Carlos E.; Martinez-Carreras, Nuria; Ector, Luc; Pfister, Laurent

2014-05-01

In recent years, calls were made for new eco-hydrological approaches to improve understanding of hydrological processes. Recently diatoms, one of the most common and diverse algal groups that can be easily transported by flowing water due to their small size (~10-200 µm), were used to detect the onset and cessation of surface runoff to small headwater streams and constrain isotopic and hydro-chemical hydrograph separation methods. While the method showed its potential in the hillslope-riparian zone-stream continuum of headwater catchments, the behavior of diatoms and their use for hydrological process research in meso-scale catchments remains uncertain. Diatoms can be a valuable support for isotope and hydro-chemical tracer methods when these become ambiguous with increasing scale. Distribution and abundance of diatom species is controlled by various environmental factors (pH, soil type, moisture conditions, exposition to sunlight, etc.). We therefore hypothesize that species abundance and composition can be used as a proxy for source areas. This presentation evaluates the potential for diatoms to trace source-areas in the nested meso-scale Attert River basin (250 km2, Luxembourg, Europe). We sampled diatom populations in streamwater during one flood event in Fall 2011 in 6 sub-catchments and the basin outlet - 17 to 28 samples/catchment for the different sampling locations. Diatoms were classified and counted in every individual sample. In total more than 400 diatom species were detected. Ordination analysis revealed a clear distinction between communities sampled in different sub-catchments. The species composition at the catchment outlet reflects a mixing of the diatom composition originating from different sub-catchments. This data suggests that diatoms indeed can reflect the geographic origin of stream water at the catchment outlet. The centroids of the ordination analysis might be linked to the physiographic characteristics (geology and land use) of the

Acid atmospheric deposition in a forested mountain catchment

Czech Academy of Sciences Publication Activity Database

Křeček, J.; Palán, L.; Stuchlík, Evžen

2017-01-01

Roč. 10, č. 4 (2017), s. 680-686 ISSN 1971-7458 Institutional support: RVO:60077344 Keywords : mountain water shed * spruce forests * acid atmospheric deposition * water resources recharge Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 1.623, year: 2016

Energy Fluxes above Three Disparate Surfaces in a Temperate Mesoscale Coastal Catchment

DEFF Research Database (Denmark)

Ringgaard, Rasmus; Herbst, Mathias; Friborg, Thomas

2011-01-01

This study is part of the long-term catchment-scale hydrological observatory, HOBE, situated in the Skjern River catchment covering 2500 km2 on the western coast of Denmark. To gain a more detailed knowledge of how evapotranspiration is controlled by the local surface and atmospheric processes......, eddy-covariance systems have been installed over an agricultural field, over a spruce [Picea abies (L.) H. Karst.] plantation, and on wet grassland. Measurements started in fall 2008, and the first annual series showed large differences in evaporative response among the surfaces. The annual sum...... was about 500 mm for the wet grassland and spruce plantation, while it was about 300 mm for the irrigated agricultural site. In winter, the actual evapotranspiration rate of the grassland and the forest were much larger than the available energy evaluated from the radiation balance, while at the same time...

Optimization of acidified oil esterification catalyzed by sulfonated cation exchange resin using response surface methodology

International Nuclear Information System (INIS)

Ma, Lingling; Han, Ying; Sun, Kaian; Lu, Jie; Ding, Jincheng

2015-01-01

Highlights: • As lipid source, acidified oil are from industrial wastes for renewable energy. • The predicted conversion rate of FFAs was 75.24% under the RSM optimized conditions. • The adsorption system was employed to remove the water produced to shift the equilibrium toward ethyl ester production. • Maximum conversion rate of 98.32% was obtained using adsorption system at optimum process parameters. • Compared with tradition methods, molecular sieve dehydration method improved the conversion rate by 23.08%. - Abstract: The esterification of acidified oil with ethanol catalyzed by sulfonated cation exchange resins (SCER) was optimized using the response surface methodology (RSM). The effects of the molar ratio of ethanol to acidified oil, reaction time and catalyst loading on the conversion rate of free fatty acids (FFAs) were investigated at the temperature of the boiling point of ethanol. Results showed that the highest conversion rate of 75.24% was obtained at the molar ratio of ethanol to acidified oil of 23.2, reaction time of 8.0 h and catalyst loading of 35.0 wt.%. Moreover, the conversion rate of FFAs was increased to 98.32% by using a water adsorption apparatus under the RSM optimized conditions. Scanning electronic microscopic–energy dispersive spectrometric (SEM–EDS), X-ray diffractometric (XRD) and thermogravimetric–derivative thermogravimetric (TG–DTG) analyses confirmed that the morphology of catalysts did not change much and the mechanical and thermal stabilities were still good after the reaction. Furthermore, SCER exhibited a high catalytic activity and stability after being reused for five successive times. The fuel properties of the biodiesel were comparable to that of ASTM, EN and GB biodiesel standard

Effects on watershed hydrology after rain forest conversion to shifting cultivation and agroforestry in Sabah, Malaysia

Energy Technology Data Exchange (ETDEWEB)

Fagerberg, Nils

1998-12-31

A paired catchment study was conducted in Mendolong, Sabah, Malaysia, to monitor the hydrological effects from conversion of secondary rain forest to shifting cultivation and agroforestry land-uses. Four different treatments were investigated: (1.) Agroforestry with initial burning and planting of fast-growing trees (Acacia mangium) and one rotation of hill rice, (2.) Agroforestry treatment as in no. 1, but without burning, (3.) Shifting cultivation with burning and one rotation of hill rice and (4.) No burning and one rotation of hill rice. A fifth catchment was used as untreated control. Waterflow was continuously measured in the streams during 41 months, between May 1994 to November 1997. 11 months were used as a calibration period before clear-felling and treatments. The data were used to determine water budgets (precipitation, runoff and evapotranspiration), runoff increases after clear-felling and changes in streamflow regimes. Regression analyses on runoff from each catchment versus the control catchment during the calibration period were used to determine the increase in runoff after clear-felling. Some unexpected losses and gains of water across the borders of the divided catchments were detected in three of the five catchments. The estimated transferred water volumes under forest cover range between 10 % and 22 % of total runoff. After clear-felling the losses and gains of water across the borders increased. The water transfer did mainly occur as sub-surface flow, probably in more permeable parts in the lower soil profile like cracks in the bedrock. Generally, the risk of deep leakage seams to increase with distance from the ridge. Hydrological effects could still be calculated through amalgamation of two of the catchments, and since the third catchment had a stable level of water gain due to unchanged conditions in the surrounding catchments. The mean areal rainfall during the period was higher than earlier measurements in the area, 4061 mm. The mean

Long-term limnological research of the Bohemian Forest lakes and their recent status

Czech Academy of Sciences Publication Activity Database

Vrba, Jaroslav (ed.); Kopáček, Jiří; Fott, J.

2000-01-01

Roč. 4, č. 4 (2000), s. 7-28 ISSN 1211-7420. [Acidified Lakes in the Bohemian/Bavarian Forest - History, Present and Future. Č. Budějovice, 21.03.2000-23.03.2000] R&D Projects: GA ČR GA206/97/0072; GA ČR GA206/98/0727; GA ČR GA206/00/0063; GA AV ČR KSK2005601 Subject RIV: DA - Hydrology ; Limnology

On the impact of the development of the Verkhnyaya Sukhona river catchment area (the Vologda Region on the chemical composition of the waters in its tributaries.

Directory of Open Access Journals (Sweden)

Ivicheva Ksenya

2017-09-01

Full Text Available The aim of the investigation was to study the influence of anthropogenic burden on the catchment areas of the rivers in Vologda Region and to establish the dependence of the chemical composition of water on pollution sources in the rivers of the Verkhnyaya Sukhona basin. In the catchment areas hydro chemical samples were taken, population density was calculated as well as the automated and visual interpretation of the main elements of the landscape was carried out. At that, forests, populated areas, farmlands and other territories changed by economic activities were identified. An increase in the pollutants concentration in the catchment areas on drawing near the regional center was detected. The development of the catchment areas varies depending on the landscape pattern and on the proximity to the city of Vologda. The population density and the relative area of settlements and farmlands increase while approaching to the city, at the same time the ratio of forests decreases. The positive correlation dependence between the phosphate content and the relative size of farmlands was shown. The main source of pollutants in the catchment areas of the Verkhnyaya Sukhona basin is the presence of settlements and high population density. Under such conditions, high concentration of sodium, chlorine, nitrogen-containing compounds as well as permanganate oxidizability are observed in water.

Nitrogen leaching and acidification during 19 years of NH4NO3 additions to a coniferous-forested catchment at Gardsjoen, Sweden (NITREX)

International Nuclear Information System (INIS)

Moldan, Filip; Wright, Richard F.

2011-01-01

The role of nitrogen (N) in acidification of soil and water has become relatively more important as the deposition of sulphur has decreased. Starting in 1991, we have conducted a whole-catchment experiment with N addition at Gardsjoen, Sweden, to investigate the risk of N saturation. We have added 41 kg N ha -1 yr -1 as NH 4 NO 3 to the ambient 9 kg N ha -1 yr -1 in fortnightly doses by means of sprinkling system. The fraction of input N lost to runoff has increased from 0% to 10%. Increased concentrations of NO 3 in runoff partially offset the decreasing concentrations of SO 4 and slowed ecosystem recovery from acid deposition. From 1990-2002, about 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. The soil N pool increased by 5%. N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g -1 . - Research highlights: → The fraction of input N lost to runoff has increased from 0% to 10%. → Increased concentrations of NO 3 in runoff slowed ecosystem recovery from acid deposition. → About 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. → N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g -1 . - N addition has led to increased flux of N and increased C sequestration at a forested catchment in Sweden; the NO 3 released has partially offset recovery from acidification.

Microbial N immobilization is of great importance in acidified mountain spruce forest soils

Czech Academy of Sciences Publication Activity Database

Tahovská, K.; Kaňa, Jiří; Bárta, J.; Oulehle, F.; Richter, A.; Šantrůčková, H.

2013-01-01

Roč. 59, April (2013), s. 58-71 ISSN 0038-0717 R&D Projects: GA AV ČR(CZ) KJB600960907; GA ČR(CZ) GAP504/12/1218 Institutional support: RVO:60077344 Keywords : N immobilization * microbial biomass * 15 N * N saturation * DOC * nitrate leaching * nitrification * C limitation * fungi/bacteria ratio * forest floor Subject RIV: CE - Biochemistry Impact factor: 4.410, year: 2013

Quality evaluation of packaged acidified vegetables subjected to continuous microwave pasteurization

Science.gov (United States)

The study evaluated the use of 915 MHz continuous microwave processing with a rotation apparatus for pasteurization of acidified vegetable packages. Broccoli florets, and 1.2 cm cubes of broccoli stems, red bell pepper, and sweetpotato were pre-equilibrated to 1 g/100 g NaCl and 0.38 g/100 mL citric...

GIS-Based KW-GIUH hydrological model of semiarid catchments: The case of Faria Catchment, Palestine

International Nuclear Information System (INIS)

Shadeed, S.; Shaheen, H.; Jayyousi, A.

2007-01-01

Among the most basic challenges of hydrology are the quantitative understanding of the processes of runoff generation and prediction of flow hydrographs. Traditional techniques have been widely applied for the estimation of runoff hydrographs of gauged catchments using historical rainfall-runoff data and unit hydrographs. Such procedures are questioned as to their reliability and their application to ungauged, arid and semiarid catchments. To overcome such difficulties, the use of physically based rainfall-runoff process of Faria Catchment using the lately developed KW-GIUH. Faria catchment, located in the northeastern part of the West Bank, Palestine, is characterized as a semiarid region with annual rainfall depths ranging on average from 150 to 640 mm at both ends of the catchment. The Geographical Information System (GIS) techniques were used to shape the geomorphological features of the catchment. A GIS based KW-GIUH hydrological model was used to stimulate the rainfall-runoff process in the three sub-catchments of Faria, namely: Al-Badan, Al-Faria and Al-Malaqi. The simulated runoff hydrographs proved that the GIS-based KW-GIUH model is applicable to semiarid regions and can be used to estimate the unit hydrographs in the West Bank catchments. (author)

Water migration of macroelements in coniferous-broad-leaved forests of Sikhote-Alin

OpenAIRE

N. K. Kozhevnikova; T. N. Lutsenko; A. G. Boldeskul; S. Yu. Lupakov; V. V. Shamov

2017-01-01

In the paper, the natural water chemical composition spatial variability studies results in the mountain forest catchment are presented. It’s shown that the catchment biotic components’ impact upon water chemical composition is detected even at input as atmospheric precipitation. The input fluxes are acid, sulfate ones with high ratio of hydrogen, potassium and dissolved organic matter. Diversity of ecotopic conditions determines the further transformation of natural water chemical composit...

Dynamics of river sediments in forested headwater streams: Plynlimon

Directory of Open Access Journals (Sweden)

G. J. L. Leeks

1997-01-01

Full Text Available Long term studies of fluvial sediment processes in the Plynlimon catchments have contributed to the assessment and quantification of plantation forestry impacts in British upland catchments, at all stages of the forest cycle. The results from the Plynlimon studies are placed in the context of the observed impacts of particular forest practices and studies of forestry effects on sediment transport elsewhere in the world. The effects associated with drain excavation, ploughing, track construction, ground and channel disruption are outlined for both bedload and, particularly, for suspended load. Finally, recent data on sediment yields from 1995 to 1997 at Plynlimon are reported and discussed in the light of longer-term sediment yield estimates. This paper also provides background information relevant to other sediment process studies which use data from the main Plynlimon sediment monitoring network.

HORTALIÇAS ACIDIFICADAS ACIDIFY VEGETABLES

Directory of Open Access Journals (Sweden)

Clícia Maria de Jesus BENEVIDES

1998-08-01

Full Text Available Objetivou-se no presente trabalho, elaborar um produto à base de hortaliças acidificadas, avaliando suas características. Foram realizadas análises físico-químicas, microbiológicas e o teste de preferência. Pelos resultados apresentados, verificou-se uma variação na acidez total e pH, ausência de contaminação microbiológica e uma aceitabilidade de 78,6% no teste de aceitação após o período de 120 dias à temp. ambiente.The objective in the present work was the preparation of a product " acidify vegetables" evaluating its characteristics. It was made physical-chemical, microbiological analyses and test of preference. From results, it was noticed a variation in the total acidity and pH , absence of microbiological contamination, and an approval of 78,6% in the test of acceptability after the period of 120 days at room temperature.

Using High-Resolution Data to Assess Land Use Impact on Nitrate Dynamics in East African Tropical Montane Catchments

Science.gov (United States)

Jacobs, Suzanne R.; Weeser, Björn; Guzha, Alphonce C.; Rufino, Mariana C.; Butterbach-Bahl, Klaus; Windhorst, David; Breuer, Lutz

2018-03-01

Land use change alters nitrate (NO3-N) dynamics in stream water by changing nitrogen cycling, nutrient inputs, uptake and hydrological flow paths. There is little empirical evidence of these processes for East Africa. We collected a unique 2 year high-resolution data set to assess the effects of land use (i.e., natural forest, smallholder agriculture and commercial tea plantations) on NO3-N dynamics in three subcatchments within a headwater catchment in the Mau Forest Complex, Kenya's largest tropical montane forest. The natural forest subcatchment had the lowest NO3-N concentrations (0.44 ± 0.043 mg N L-1) with no seasonal variation. NO3-N concentrations in the smallholder agriculture (1.09 ± 0.11 mg N L-1) and tea plantation (2.13 ± 0.19 mg N L-1) subcatchments closely followed discharge patterns, indicating mobilization of NO3-N during the rainy seasons. Hysteresis patterns of rainfall events indicate a shift from subsurface flow in the natural forest to surface runoff in agricultural subcatchments. Distinct peaks in NO3-N concentrations were observed during rainfall events after a longer dry period in the forest and tea subcatchments. The high-resolution data set enabled us to identify differences in NO3-N transport of catchments under different land use, such as enhanced NO3-N inputs to the stream during the rainy season and higher annual export in agricultural subcatchments (4.9 ± 0.3 to 12.0 ± 0.8 kg N ha-1 yr-1) than in natural forest (2.6 ± 0.2 kg N ha-1 yr-1). This emphasizes the usefulness of our monitoring approach to improve the understanding of land use effects on riverine N exports in tropical landscapes, but also the need to apply such methods in other regions.

The impact of the growth of new plantation forestry on evaporation and streamflow in the Llanbrynmair catchments

Directory of Open Access Journals (Sweden)

J. A. Hudson

1997-01-01

Full Text Available Annual water balances (1983-1995 for the Cwm and Delyn catchments at Llanbrynmair Moor in mid-Wales have been used to quantify the hydrological effects of the land use change in the Cwm from moorland to forestry. Initially, the actual evaporation (precipitation minus streamflow of the Cwm catchment declined rapidly relative to the Delyn, due to the disruption of the vegetation by ploughing the ground in preparation for planting the trees. It then increased, more quickly than expected, to greater levels than for the original moorland since in the early stages of forest growth a dense understorey of dwarf shrubs contributed to both interception and transpiration.

Diverse coral communities in naturally acidified waters of a Western Pacific reef

Science.gov (United States)

Shamberger, Kathryn E. F.; Cohen, Anne L.; Golbuu, Yimnang; McCorkle, Daniel C.; Lentz, Steven J.; Barkley, Hannah C.

2014-01-01

Anthropogenic carbon dioxide emissions are acidifying the oceans, reducing the concentration of carbonate ions ([CO32-]) that calcifying organisms need to build and cement coral reefs. To date, studies of a handful of naturally acidified reef systems reveal depauperate communities, sometimes with reduced coral cover and calcification rates, consistent with results of laboratory-based studies. Here we report the existence of highly diverse, coral-dominated reef communities under chronically low pH and aragonite saturation state (Ωar). Biological and hydrographic processes change the chemistry of the seawater moving across the barrier reefs and into Palau's Rock Island bays, where levels of acidification approach those projected for the western tropical Pacific open ocean by 2100. Nevertheless, coral diversity, cover, and calcification rates are maintained across this natural acidification gradient. Identifying the combination of biological and environmental factors that enable these communities to persist could provide important insights into the future of coral reefs under anthropogenic acidification.

The chemical behavior of acidified chromium (3) solutions. B.S. Thesis

Science.gov (United States)

Terman, D. K.

1981-01-01

A unique energy-storage system has been developed at NASA's Lewis Research Center called REDOX. This NASA-REDOX system is an electrochemical storage device that utilized the oxidation and reduction of two fully soluble redox couples for charging and discharging. The redox couples now being investigated are acidified chloride solutions of chromium (Cr(+2)/Cr(+3)) and iron (Fe(+2)/Fe(+3)).

Spatially explicit characterization of acidifying and eutrophying air pollution in life-cycle assessment

NARCIS (Netherlands)

Huijbregts, Mark A J; Schöpp, Wolfgang; Verkuijlen, Evert; Heijungs, Reinout; Reijnders, Lucas

2001-01-01

Simple models are often used to assess the potential impact of acidifying and eutrophying substances released during the life cycle of products. As fate, background depositions, and ecosystem sensitivity are not included in these models, environmental life-cycle assessment of products (LCA) may

Hydrologic and forest management controls on DOC dynamics in the small watersheds of the H.J. Andrews Experimental Forest, OR

Science.gov (United States)

Lajtha, K.; Jones, J. A.

2016-12-01

Dissolved organic carbon (DOC) export from hillslopes to streams is an important component of the carbon cycle of a catchment and may be a critical source of energy for the aquatic food web in receiving waters. Using a long-term record of DOC and other dissolved nutrients and elements from paired watersheds from the H.J. Andrews Experimental Forest in Oregon, we explored hydrologic, climatic, and land-use controls on seasonal and inter-annual patterns of DOC flux in a seasonally dry ecosystem. Seasonal patterns of DOC flux demonstrated source limitations to DOC export, with DOC concentrations highest immediately following the first rains after a dry summer, and lowest after winter rains. In contrast, more geochemically-controlled elements showed simple dilution-concentration patterns with no seasonal hysteresis. Inter-annual patterns of DOC flux, however, did not provide evidence of source limitation, with DOC flux within a watershed tightly correlated to total discharge but not temperature. Among watersheds, forest harvest, even over 50 years ago, significantly reduced DOC flux but not fluxes of other elements including N; this response was linked to the loading of coarse woody debris to the forest floor. Chemical fingerprinting of DOC revealed that old-growth watersheds had higher fluxes of DOC characteristic of forest floor organic materials, likely delivered to streams through more surficial preferential flow pathways not subject to microbial alteration, respiration, or sorption losses. Taken together these results suggest that the biogeochemical composition of forested streams reflects both current hydrologic patterns and also processes that occurred many decades ago within the catchment.

Long term effects of ash recycling on soil and water chemistry in forests

International Nuclear Information System (INIS)

Westling, Olle; Kronnaes, Veronika

2006-02-01

IVL Swedish Environmental Research Institute has studied the long-term need of compensatory fertilisation (e.g. wood ash recycling) after whole tree harvest in coniferous forests in Sweden. The study is based on dynamic model calculations with scenarios including reduced atmospheric deposition of air pollutants and different intensity of forest management. The possibilities to counteract acidification in soil and water with application of stabilised wood ash are discussed. The reduction in deposition of acidifying air pollutants in Sweden up to 2010 is expected to contribute to a significant recovery from acidification in soil- and runoff water in forests. The recovery of the forest soil (e.g. base saturation ) will, however, be slow according to the model calculations, especially if compensatory fertilisation is not carried out in managed areas. The model calculations indicate that the harvest of stemwood will have limited impact on the future acidity of soil and run off water from well drained forest soils. This conclusion is based on a comparison with a scenario where no harvest is assumed. More important for recovery from acidification is further reduction of acidifying air pollutants, even after 2010. Harvest of stemwood in combination with extraction of harvest residues has the potential to cause significant and long term acidification of soils in the future, especially in areas with high forest production and slow weathering rate. The results of the study indicate a need of compensatory fertilisation in these areas if whole tree harvest is applied, especially if the deposition of air pollutants have been high in the past. Field studies have shown that acidification effects of whole tree harvest can be counteracted by wood ash recycling to forest soils, due to the high content of calcium- and magnesium-rich minerals in the ashes. However, the dose should be adjusted to the need of increasing the acid neutralising capacity in the soil and runoff and the actual

Hydrological response to bauxite mining and rehabilitation in the jarrah forest in south west Australia

OpenAIRE

Andrew H. Grigg

2017-01-01

Study region: Jarrah forest in south west Australia. Study focus: The hydrological response to bauxite mining in the jarrah forest could differ from other land uses such as timber harvesting or clearing for agriculture, since mining involves excavation of the upper regolith in addition to changes in forest cover due to clearing and subsequent rehabilitation. Three catchments, one subject to mining, a second subject to an intensive forest thinning treatment and an untreated control were mon...

Organizing groundwater regimes and response thresholds by soils: A framework for understanding runoff generation in a headwater catchment

Science.gov (United States)

John P. Gannon; Scott W. Bailey; Kevin J. McGuire

2014-01-01

A network of shallow groundwater wells in a headwater catchment at the Hubbard Brook Experimental Forest in New Hampshire, U.S. was used to investigate the hydrologic behavior of five distinct soil morphological units. The soil morphological units were hypothesized to be indicative of distinct water table regimes. Water table fluctuations in the wells were...

Effects of lakes and reservoirs on annual river nitrogen, phosphorus, and sediment export in agricultural and forested landscapes

Science.gov (United States)

Powers, Stephen M.; Robertson, Dale M.; Stanley, Emily H.

2014-01-01

Recently, effects of lakes and reservoirs on river nutrient export have been incorporated into landscape biogeochemical models. Because annual export varies with precipitation, there is a need to examine the biogeochemical role of lakes and reservoirs over time frames that incorporate interannual variability in precipitation. We examined long-term (~20 years) time series of river export (annual mass yield, Y, and flow-weighted mean annual concentration, C) for total nitrogen (TN), total phosphorus (TP), and total suspended sediment (TSS) from 54 catchments in Wisconsin, USA. Catchments were classified as small agricultural, large agricultural, and forested by use of a cluster analysis, and these varied in lentic coverage (percentage of catchment lake or reservoir water that was connected to river network). Mean annual export and interannual variability (CV) of export (for both Y and C) were higher in agricultural catchments relative to forested catchments for TP, TN, and TSS. In both agricultural and forested settings, mean and maximum annual TN yields were lower in the presence of lakes and reservoirs, suggesting lentic denitrification or N burial. There was also evidence of long-term lentic TP and TSS retention, especially when viewed in terms of maximum annual yield, suggesting sedimentation during high loading years. Lentic catchments had lower interannual variability in export. For TP and TSS, interannual variability in mass yield was often >50% higher than interannual variability in water yield, whereas TN variability more closely followed water (discharge) variability. Our results indicate that long-term mass export through rivers depends on interacting terrestrial, aquatic, and meteorological factors in which the presence of lakes and reservoirs can reduce the magnitude of export, stabilize interannual variability in export, as well as introduce export time lags.

Analyzing catchment behavior through catchment modeling in the Gilgel Abay, Upper Blue Nile River Basin, Ethiopia

Directory of Open Access Journals (Sweden)

S. Uhlenbrook

2010-10-01

Full Text Available Understanding catchment hydrological processes is essential for water resources management, in particular in data scarce regions. The Gilgel Abay catchment (a major tributary into Lake Tana, source of the Blue Nile is undergoing intensive plans for water management, which is part of larger development plans in the Blue Nile basin in Ethiopia. To obtain a better understanding of the water balance dynamics and runoff generation mechanisms and to evaluate model transferability, catchment modeling has been conducted using the conceptual hydrological model HBV. Accordingly, the catchment of the Gilgel Abay has been divided into two gauged sub-catchments (Upper Gilgel Abay and Koga and the un-gauged part of the catchment. All available data sets were tested for stationarity, consistency and homogeneity and the data limitations (quality and quantity are discussed. Manual calibration of the daily models for three different catchment representations, i.e. (i lumped, (ii lumped with multiple vegetation zones, and (iii semi-distributed with multiple vegetation and elevation zones, showed good to satisfactory model performances with Nash-Sutcliffe efficiencies R_eff > 0.75 and > 0.6 for the Upper Gilgel Abay and Koga sub-catchments, respectively. Better model results could not be obtained with manual calibration, very likely due to the limited data quality and model insufficiencies. Increasing the computation time step to 15 and 30 days improved the model performance in both sub-catchments to R_eff > 0.8. Model parameter transferability tests have been conducted by interchanging parameters sets between the two gauged sub-catchments. Results showed poor performances for the daily models (0.30 < R_eff < 0.67, but better performances for the 15 and 30 days models, R_eff > 0.80. The transferability tests together with a sensitivity analysis using Monte Carlo simulations (more than 1 million

Estimation of Above Ground Biomass in a Tropical Mountain Forest in Southern Ecuador Using Airborne LiDAR Data

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Víctor González-Jaramillo

2018-04-01

Full Text Available A reliable estimation of Above Ground Biomass (AGB in Tropical Mountain Forest (TMF is still complicated, due to fast-changing climate and topographic conditions, which modifies the forest structure within fine scales. The variations in vertical and horizontal forest structure are hardly detectable by small field plots, especially in natural TMF due to the high tree diversity and the inaccessibility of remote areas. Therefore, the present approach used remotely sensed data from a Light Detection and Ranging (LiDAR sensor in combination with field measurements to estimate AGB accurately for a catchment in the Andes of south-eastern Ecuador. From the LiDAR data, information about horizontal and vertical structure of the TMF could be derived and the vegetation at tree level classified, differentiated between the prevailing forest types (ravine forest, ridge forest and Elfin Forest. Furthermore, topographical variables (Topographic Position Index, TPI; Morphometric Protection Index, MPI were calculated by means of the high-resolution LiDAR data to analyse the AGB distribution within the catchment. The field measurements included different tree parameters of the species present in the plots, which were used to determine the local mean Wood Density (WD as well as the specific height-diameter relationship to calculate AGB, applying regional scale modelling at tree level. The results confirmed that field plot measurements alone cannot capture completely the forest structure in TMF but in combination with high resolution LiDAR data, applying a classification at tree level, the AGB amount (Mg ha−1 and its distribution in the entire catchment could be estimated adequately (model accuracy at tree level: R2 > 0.91. It was found that the AGB distribution is strongly related to ridges and depressions (TPI and to the protection of the site (MPI, because high AGB was also detected at higher elevations (up to 196.6 Mg ha−1, above 2700 m, if the site is

Anthropogenic disturbance in tropical forests can double biodiversity loss from deforestation.

Science.gov (United States)

Barlow, Jos; Lennox, Gareth D; Ferreira, Joice; Berenguer, Erika; Lees, Alexander C; Mac Nally, Ralph; Thomson, James R; Ferraz, Silvio Frosini de Barros; Louzada, Julio; Oliveira, Victor Hugo Fonseca; Parry, Luke; Solar, Ricardo Ribeiro de Castro; Vieira, Ima C G; Aragão, Luiz E O C; Begotti, Rodrigo Anzolin; Braga, Rodrigo F; Cardoso, Thiago Moreira; de Oliveira, Raimundo Cosme; Souza, Carlos M; Moura, Nárgila G; Nunes, Sâmia Serra; Siqueira, João Victor; Pardini, Renata; Silveira, Juliana M; Vaz-de-Mello, Fernando Z; Veiga, Ruan Carlo Stulpen; Venturieri, Adriano; Gardner, Toby A

2016-07-07

Concerted political attention has focused on reducing deforestation, and this remains the cornerstone of most biodiversity conservation strategies. However, maintaining forest cover may not reduce anthropogenic forest disturbances, which are rarely considered in conservation programmes. These disturbances occur both within forests, including selective logging and wildfires, and at the landscape level, through edge, area and isolation effects. Until now, the combined effect of anthropogenic disturbance on the conservation value of remnant primary forests has remained unknown, making it impossible to assess the relative importance of forest disturbance and forest loss. Here we address these knowledge gaps using a large data set of plants, birds and dung beetles (1,538, 460 and 156 species, respectively) sampled in 36 catchments in the Brazilian state of Pará. Catchments retaining more than 69–80% forest cover lost more conservation value from disturbance than from forest loss. For example, a 20% loss of primary forest, the maximum level of deforestation allowed on Amazonian properties under Brazil’s Forest Code, resulted in a 39–54% loss of conservation value: 96–171% more than expected without considering disturbance effects. We extrapolated the disturbance-mediated loss of conservation value throughout Pará, which covers 25% of the Brazilian Amazon. Although disturbed forests retained considerable conservation value compared with deforested areas, the toll of disturbance outside Pará’s strictly protected areas is equivalent to the loss of 92,000–139,000 km2 of primary forest. Even this lowest estimate is greater than the area deforested across the entire Brazilian Amazon between 2006 and 2015 (ref. 10). Species distribution models showed that both landscape and within-forest disturbances contributed to biodiversity loss, with the greatest negative effects on species of high conservation and functional value. These results demonstrate an urgent need

Modeling radiocesium transport from a river catchment based on a physically-based distributed hydrological and sediment erosion model.

Science.gov (United States)

Kinouchi, Tsuyoshi; Yoshimura, Kazuya; Omata, Teppei

2015-01-01

The accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March 2011 resulted in the deposition of large quantities of radionuclides, such as (134)Cs and (137)Cs, over parts of eastern Japan. Since then high levels of radioactive contamination have been detected in large areas, including forests, agricultural land, and residential areas. Due to the strong adsorption capability of radiocesium to soil particles, radiocesium migrates with eroded sediments, follows the surface flow paths, and is delivered to more populated downstream regions and eventually to the Pacific Ocean. It is therefore important to understand the transport of contaminated sediments in the hydrological system and to predict changes in the spatial distribution of radiocesium concentrations by taking the land-surface processes related to sediment migration into consideration. In this study, we developed a distributed model to simulate the transport of water and contaminated sediment in a watershed hydrological system, and applied this model to a partially forested mountain catchment located in an area highly contaminated by the radioactive fallout. Observed discharge, sediment concentration, and cesium concentration measured from June 2011 until December 2012 were used for calibration of model parameters. The simulated discharge and sediment concentration both agreed well with observed values, while the cesium concentration was underestimated in the initial period following the accident. This result suggests that the leaching of radiocesium from the forest canopy, which was not considered in the model, played a significant role in its transport from the catchment. Based on the simulation results, we quantified the long-term fate of radiocesium over the study area and estimated that the effective half-life of (137)Cs deposited in the study area will be approximately 22 y due to the export of contaminated sediment by land-surface processes, and the amount of (137)Cs remaining in the

Does Evapotranspiration Increase When Forests are converted to Grasslands?

Science.gov (United States)

Varcoe, Robert; Sterling, Shannon

2017-04-01

The conversion of forests to grasslands (FGC) is a widespread land cover change (LCC) and is also among the most commonly studied changes with respect to its impact on ET; such research employs a variety of experimental approaches, including, paired catchment (PC), Budyko and land surface models (LSM), and measurement methods, including the catchment water balance (CWB), eddy covariance (EC) and remote sensing (RS). Until recently, there has been consensus in the scientific literature that rates of ET decrease when a forest is converted to grassland; however, this consensus has recently come into question. Williams (2012) applied the Budyko framework to a global network of eddy covariance measurements with the results that grasslands have a 9% greater evaporative index than forests. In addition, HadGEM2, a recent Hadley Centre LSM, produced increased ET in the northern Amazon Basin after simulating global scale tropical deforestation (Brovkin et al., 2015). Here we present an analysis of available estimates of how ET rates change with FGC to increase our understanding of the forest - grassland-ET paradigm. We used two datasets to investigate the impacts land cover change on ET. I compiled a dataset of change in ET with land cover change (ΔETLCC) using published experiments that compare forest and grassland ET under conditions controlled for meteorological and landscape influences. Using the ΔETLCC dataset, we show that, in all cases, forest ET is higher than grassland under controlled conditions. Results suggest that the eddy covariance method measures smaller changes in ET when forests are converted to grasslands, though more data are needed for this result to be statistically significant. Finally, GETA2.0, a new global dataset of annual ET, projects that forest ET is greater than grassland, except at high latitudes and areas where orography influences precipitation (P). The data included in this study represent the data available on forest and grassland ET

Changes in land cover, rainfall and stream flow in Upper Gilgel Abbay catchment, Blue Nile basin – Ethiopia

Directory of Open Access Journals (Sweden)

T. H. M. Rientjes

2011-06-01

Full Text Available In this study we evaluated changes in land cover and rainfall in the Upper Gilgel Abbay catchment in the Upper Blue Nile basin and how changes affected stream flow in terms of annual flow, high flows and low flows. Land cover change assessment was through classification analysis of remote sensing based land cover data while assessments on rainfall and stream flow data are by statistical analysis. Results of the supervised land cover classification analysis indicated that 50.9 % and 16.7 % of the catchment area was covered by forest in 1973 and 2001, respectively. This significant decrease in forest cover is mainly due to expansion of agricultural land.

By use of a change detection procedure, three periods were identified for which changes in rainfall and stream flow were analyzed. Rainfall was analyzed at monthly base by use of the Mann-Kendall test statistic and results indicated a statistically significant, decreasing trend for most months of the year. However, for the wet season months of June, July and August rainfall has increased. In the period 1973–2005, the annual flow of the catchment decreased by 12.1 %. Low flow and high flow at daily base were analyzed by a low flow and a high flow index that is based on a 95 % and 5 % exceedance probability. Results of the low flow index indicated decreases of 18.1 % and 66.6 % for the periods 1982–2000 and 2001–2005 respectively. Results of high flows indicated an increase of 7.6 % and 46.6 % for the same periods. In this study it is concluded that over the period 1973–2005 stream flow has changed in the Gilgel Abbay catchment by changes in land cover and changes in rainfall.

Elevated Annual Runoff Ratios in Pacific Northwest Catchments Impacted by Epidemic Foliage Disease of Douglas-fir

Science.gov (United States)

Bladon, K. D.; Bywater-Reyes, S.; LeBoldus, J. M.; Segura, C.; Ritokova, G.; Shaw, D. C.

2017-12-01

Catchments in the Western United States are undergoing unprecedented levels of tree die-off and/or reduced vigor due to increased severity of wildfire, drought, insect outbreaks, and disease. In the U.S. Pacific Northwest, Swiss needle cast (SNC) is the most damaging foliar disease of Douglas-fir (Pseudotsuga menziesii), physically obstructing stomata and preventing CO2 uptake and transpiration. A recent analysis in coastal Oregon indicated a substantial increase in area affected by the disease, from 530.5 km2 in 1996 to 2,387.1 km2 in 2015. Deforestation or reduced tree vigor can have profound impacts on catchment hydrology, in theory, producing increased streamflow due to reduced interception and transpiration. However, these increases have not always been detectable as impacts also depend on factors such as climate and vegetation composition. Moreover, press disturbances, such as insect outbreaks or disease, often do not result in complete removal of understorey or canopy vegetation. We analyzed trends in annual runoff ratios (quotient of discharge divided by precipitation) from 1990-2015 in 12 catchments (183-1,744 km2) in western Oregon. In general, runoff ratios increased by 10-27% in catchments with a total area of SNC >10%, with the most substantial runoff increases in catchments with SNC impacting >25% of the area. Interestingly, the most severely impacted catchment ( 90.5% SNC) showed a decrease in runoff. This is consistent with a potential compensatory response from understory western hemlock (Tsuga heterophylla) trees, a phenomenon observed in the most severely impacted sites. Findings from this study are important for assessing the impacts of biotic forest disturbances on water supply and aquatic ecosystem health.

Identifying dominant controls on hydrologic parameter transfer from gauged to ungauged catchments: a comparative hydrology approach

Science.gov (United States)

Singh, R.; Archfield, S.A.; Wagener, T.

2014-01-01

Daily streamflow information is critical for solving various hydrologic problems, though observations of continuous streamflow for model calibration are available at only a small fraction of the world’s rivers. One approach to estimate daily streamflow at an ungauged location is to transfer rainfall–runoff model parameters calibrated at a gauged (donor) catchment to an ungauged (receiver) catchment of interest. Central to this approach is the selection of a hydrologically similar donor. No single metric or set of metrics of hydrologic similarity have been demonstrated to consistently select a suitable donor catchment. We design an experiment to diagnose the dominant controls on successful hydrologic model parameter transfer. We calibrate a lumped rainfall–runoff model to 83 stream gauges across the United States. All locations are USGS reference gauges with minimal human influence. Parameter sets from the calibrated models are then transferred to each of the other catchments and the performance of the transferred parameters is assessed. This transfer experiment is carried out both at the scale of the entire US and then for six geographic regions. We use classification and regression tree (CART) analysis to determine the relationship between catchment similarity and performance of transferred parameters. Similarity is defined using physical/climatic catchment characteristics, as well as streamflow response characteristics (signatures such as baseflow index and runoff ratio). Across the entire US, successful parameter transfer is governed by similarity in elevation and climate, and high similarity in streamflow signatures. Controls vary for different geographic regions though. Geology followed by drainage, topography and climate constitute the dominant similarity metrics in forested eastern mountains and plateaus, whereas agricultural land use relates most strongly with successful parameter transfer in the humid plains.

Catchment-scale evaluation of pollution potential of urban snow at two residential catchments in southern Finland.

Science.gov (United States)

Sillanpää, Nora; Koivusalo, Harri

2013-01-01

Despite the crucial role of snow in the hydrological cycle in cold climate conditions, monitoring studies of urban snow quality often lack discussions about the relevance of snow in the catchment-scale runoff management. In this study, measurements of snow quality were conducted at two residential catchments in Espoo, Finland, simultaneously with continuous runoff measurements. The results of the snow quality were used to produce catchment-scale estimates of areal snow mass loads (SML). Based on the results, urbanization reduced areal snow water equivalent but increased pollutant accumulation in snow: SMLs in a medium-density residential catchment were two- to four-fold higher in comparison with a low-density residential catchment. The main sources of pollutants were related to vehicular traffic and road maintenance, but also pet excrement increased concentrations to a high level. Ploughed snow can contain 50% of the areal pollutant mass stored in snow despite its small surface area within a catchment.

Importance of vegetation, topography and flow paths for water transit times of base flow in alpine headwater catchments

Directory of Open Access Journals (Sweden)

M. H. Mueller

2013-04-01

Full Text Available The mean transit time (MTT of water in a catchment gives information about storage, flow paths, sources of water and thus also about retention and release of solutes in a catchment. To our knowledge there are only a few catchment studies on the influence of vegetation cover changes on base flow MTTs. The main changes in vegetation cover in the Swiss Alps are massive shrub encroachment and forest expansion into formerly open habitats. Four small and relatively steep headwater catchments in the Swiss Alps (Ursern Valley were investigated to relate different vegetation cover to water transit times. Time series of water stable isotopes were used to calculate MTTs. The high temporal variation of the stable isotope signals in precipitation was strongly dampened in stream base flow samples. MTTs of the four catchments were 70 to 102 weeks. The strong dampening of the stable isotope input signal as well as stream water geochemistry points to deeper flow paths and mixing of waters of different ages at the catchments' outlets. MTTs were neither related to topographic indices nor vegetation cover. The major part of the quickly infiltrating precipitation likely percolates through fractured and partially karstified deeper rock zones, which increases the control of bedrock flow paths on MTT. Snow accumulation and the timing of its melt play an important role for stable isotope dynamics during spring and early summer. We conclude that, in mountainous headwater catchments with relatively shallow soil layers, the hydrogeological and geochemical patterns (i.e. geochemistry, porosity and hydraulic conductivity of rocks and snow dynamics influence storage, mixing and release of water in a stronger way than vegetation cover or topography do.

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...... transport where the level of detail can be suited to the purpose....

Effects of Forest Cover Change on Flood Characteristics in the Upper Citarum Watershed

Directory of Open Access Journals (Sweden)

Bambang Dwi Dasanto

2014-12-01

Full Text Available Information on the effect of forest cover changes on streamflow (river discharge in large-scale catchment is important to be studied. The rate of forest cover change in the Upper Citarum Watershed as a large-scale catchment is high enough to drive streamflow change, such as increase of discharge level, or flood volume. Within the research area, flood would occur when the volume of streamflow exceeded the canal capacity and inundated areas that were normally dry. Therefore, this research focused on identifying the effects of forest cover change on flood events and its distribution. The research consisted of 2 main stages; firstly, building geometric data of river and performing frequency analysis of historical and scenario discharges using an approach of probability distribution; and, secondly, flood inundation mapping using HEC-RAS model. The results showed that forest reduction have affected water yield in the downstream of Upper Citarum Watershed. In each return period, this reduction have increased river discharge level and affected the spread of flooded areas. In 2-year return period, the extent of flood as an impact of forest reduction was estimated to decrease slowly. However, in the return period of more than 2 years, the spread of flooded areas increased sharply. These proved that forest cover reduction would always increase the discharge value, but it did not always expand the inundated area.

Planning Method of Eco-environment Restoration Based on Enlarging Terrace and De-farming in Loess Hilly Region——A Case Study of Yangou Catchment

Institute of Scientific and Technical Information of China (English)

Lijuan; DANG; Yong; XU

2013-01-01

After expatiating the guiding ideology,contents,standards and principles of eco-environment restoration based on enlarging terrace and de-farming,this paper discussed the planning method and technical flow of enlarging terrace and garden plot in a small catchment of loess hilly region by means of GIS spatial analysis technology,and then the planning method was applied in Yangou catchment.The result showed that it is practicabl,and the areas of newly-built terrace and garden plot in Yangou catchment are at least 295.06 and 4.61 hm2,so that the areas of basic farmland and garden plot reach 359.23 and 622.69 hm2.After the land use structure is regulated,the forest coverage is 48.87%,and the permanent vegetation coverage is about 75% in Yangou catchment,while sediment reduction benefit is above 80% in slope land.In agricultural development,Yangou catchment can yield 1 645.13 tons of food supplies,above 9 340 tons of apples,and can feed 7 500 sheep every year.

Quantifying spatial distribution of snow depth errors from LiDAR using Random Forests

Science.gov (United States)

Tinkham, W.; Smith, A. M.; Marshall, H.; Link, T. E.; Falkowski, M. J.; Winstral, A. H.

2013-12-01

There is increasing need to characterize the distribution of snow in complex terrain using remote sensing approaches, especially in isolated mountainous regions that are often water-limited, the principal source of terrestrial freshwater, and sensitive to climatic shifts and variations. We apply intensive topographic surveys, multi-temporal LiDAR, and Random Forest modeling to quantify snow volume and characterize associated errors across seven land cover types in a semi-arid mountainous catchment at a 1 and 4 m spatial resolution. The LiDAR-based estimates of both snow-off surface topology and snow depths were validated against ground-based measurements across the catchment. Comparison of LiDAR-derived snow depths to manual snow depth surveys revealed that LiDAR based estimates were more accurate in areas of low lying vegetation such as shrubs (RMSE = 0.14 m) as compared to areas consisting of tree cover (RMSE = 0.20-0.35 m). The highest errors were found along the edge of conifer forests (RMSE = 0.35 m), however a second conifer transect outside the catchment had much lower errors (RMSE = 0.21 m). This difference is attributed to the wind exposure of the first site that led to highly variable snow depths at short spatial distances. The Random Forest modeled errors deviated from the field measured errors with a RMSE of 0.09-0.34 m across the different cover types. Results show that snow drifts, which are important for maintaining spring and summer stream flows and establishing and sustaining water-limited plant species, contained 30 × 5-6% of the snow volume while only occupying 10% of the catchment area similar to findings by prior physically-based modeling approaches. This study demonstrates the potential utility of combining multi-temporal LiDAR with Random Forest modeling to quantify the distribution of snow depth with a reasonable degree of accuracy. Future work could explore the utility of Terrestrial LiDAR Scanners to produce validation of snow-on surface

Effects of Forest Cover Change on Flood Characteristics in the Upper Citarum Watershed

Directory of Open Access Journals (Sweden)

Bambang Dwi Dasanto

2015-02-01

Full Text Available Information on the effect of forest cover changes on streamflow (river discharge in large-scale catchment is important to be studied. The rate of forest cover change in the Upper Citarum Watershed as a large-scale catchment is high enough to drive streamflow change, such as increase of discharge level, or flood volume. Within the research area, flood would occur when the volume of streamflow exceeded the canal capacity and inundated areas that were normally dry. Therefore, this research focused on identifying the effects of forest cover change on flood events and its distribution. The research consisted of 2 main stages; firstly, building geometric data of river and performing frequency analysis of historical and scenario discharges using an approach of probability distribution; and, secondly, flood inundation mapping using HEC-RAS model. The results showed that forest reduction have affected water yield in the downstream of Upper Citarum Watershed. In each return period, this reduction have increased river discharge level and affected the spread of flooded areas. In 2-year return period, the extent of flood as an impact of forest reduction was estimated to decrease slowly. However, in the return period of more than 2 years, the spread of flooded areas increased sharply. These proved that forest cover reduction would always increase the discharge value, but it did not always expand the inundated area.Keywords: geometric data, forest cover, water yield, return period

Ecosystem processes at the watershed scale: hydrologic vegetation gradient as an indicator for lateral hydrologic connectivity of headwater catchments

Science.gov (United States)

Taehee Hwang; James M. Vose; Christina. Tague

2012-01-01

Lateral water flow in catchments can produce important patterns in water and nutrient fluxes and stores and also influences the long-term spatial development of forest ecosystems. Specifically, patterns of vegetation type and density along hydrologic flow paths can represent a signal of the redistribution of water and nitrogen mediated by lateral hydrologic flow. This...

Complex responses of intertidal molluscan embryos to a warming and acidifying ocean in the presence of UV radiation.

Directory of Open Access Journals (Sweden)

Andrew R Davis

Full Text Available Climate change and ocean acidification will expose marine organisms to synchronous multiple stressors, with early life stages being potentially most vulnerable to changing environmental conditions. We simultaneously exposed encapsulated molluscan embryos to three abiotic stressors-acidified conditions, elevated temperate, and solar UV radiation in large outdoor water tables in a multifactorial design. Solar UV radiation was modified with plastic filters, while levels of the other factors reflected IPCC predictions for near-future change. We quantified mortality and the rate of embryonic development for a mid-shore littorinid, Bembicium nanum, and low-shore opisthobranch, Dolabrifera brazieri. Outcomes were consistent for these model species with embryos faring significantly better at 26°C than 22°C. Mortality sharply increased at the lowest temperature (22°C and lowest pH (7.6 examined, producing a significant interaction. Under these conditions mortality approached 100% for each species, representing a 2- to 4-fold increase in mortality relative to warm (26°C non-acidified conditions. Predictably, development was more rapid at the highest temperature but this again interacted with acidified conditions. Development was slowed under acidified conditions at the lowest temperature. The presence of UV radiation had minimal impact on the outcomes, only slowing development for the littorinid and not interacting with the other factors. Our findings suggest that a warming ocean, at least to a threshold, may compensate for the effects of decreasing pH for some species. It also appears that stressors will interact in complex and unpredictable ways in a changing climate.

Complex Responses of Intertidal Molluscan Embryos to a Warming and Acidifying Ocean in the Presence of UV Radiation

Science.gov (United States)

Davis, Andrew R.; Coleman, Daniel; Broad, Allison; Byrne, Maria; Dworjanyn, Symon A.; Przeslawski, Rachel

2013-01-01

Climate change and ocean acidification will expose marine organisms to synchronous multiple stressors, with early life stages being potentially most vulnerable to changing environmental conditions. We simultaneously exposed encapsulated molluscan embryos to three abiotic stressors—acidified conditions, elevated temperate, and solar UV radiation in large outdoor water tables in a multifactorial design. Solar UV radiation was modified with plastic filters, while levels of the other factors reflected IPCC predictions for near-future change. We quantified mortality and the rate of embryonic development for a mid-shore littorinid, Bembicium nanum, and low-shore opisthobranch, Dolabrifera brazieri. Outcomes were consistent for these model species with embryos faring significantly better at 26°C than 22°C. Mortality sharply increased at the lowest temperature (22°C) and lowest pH (7.6) examined, producing a significant interaction. Under these conditions mortality approached 100% for each species, representing a 2- to 4-fold increase in mortality relative to warm (26°C) non-acidified conditions. Predictably, development was more rapid at the highest temperature but this again interacted with acidified conditions. Development was slowed under acidified conditions at the lowest temperature. The presence of UV radiation had minimal impact on the outcomes, only slowing development for the littorinid and not interacting with the other factors. Our findings suggest that a warming ocean, at least to a threshold, may compensate for the effects of decreasing pH for some species. It also appears that stressors will interact in complex and unpredictable ways in a changing climate. PMID:23405238

The role of bedrock groundwater in rainfall-runoff response at hillslope and catchment scales

Science.gov (United States)

Gabrielli, C. P.; McDonnell, J. J.; Jarvis, W. T.

2012-07-01

SummaryBedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Direct hydrometric measurements have been limited due to the logistical challenges associated with drilling through hard rock in steep, remote and often roadless terrain. We used a new portable bedrock drilling system to explore bedrock groundwater dynamics aimed at quantifying bedrock groundwater contributions to hillslope flow and catchment runoff. We present results from the Maimai M8 research catchment in New Zealand and Watershed 10 (WS10) at the H.J. Andrews Experimental Forest in Oregon, USA. Analysis of bedrock groundwater at Maimai, through a range of flow conditions, revealed that the bedrock water table remained below the soil-bedrock interface, indicating that the bedrock aquifer has minimal direct contributions to event-based hillslope runoff. However, the bedrock water table did respond significantly to storm events indicating that there is a direct connection between hillslope processes and the underlying bedrock aquifer. WS10 groundwater dynamics were dominated by fracture flow. A highly fractured and transmissive zone within the upper one meter of bedrock conducted rapid lateral subsurface stormflow and lateral discharge. The interaction of subsurface stormflow with bedrock storage directly influenced the measured hillslope response, solute transport and computed mean residence time. This research reveals bedrock groundwater to be an extremely dynamic component of the hillslope hydrological system and our comparative analysis illustrates the potential range of hydrological and geological controls on runoff generation in headwater catchments.

Diffusion and export dynamics of 137Cs deposited on the forested area in Fukushima after the nuclear power plant accident in March 2011. Preliminary results

International Nuclear Information System (INIS)

Ohte, Nobuhito; Iseda, Kohei; Tanoi, Keitaro; Murakami, Masashi; Suzuki, Takahiro; Ishii, Nobuyoshi

2012-01-01

A massive amount of radioactive substances, including cesium-137 ( 137 Cs), emitted from the disabled nuclear power plant, has been deposited on the forested areas in the northeastern region of Honshu Island, Japan after the Fukushima Daiichi nuclear power plant accident. Forests in these regions are particularly important, not only for the forest products industry but also for source areas of drinking water and for residential environments. To clarify the mechanisms of diffusion and export of 137 Cs deposited on the forested ecosystem, we initiated intensive field observations in a small catchment that included forest and farmlands. Specifically, we were interested in the Kami-Oguni River catchment that is located in the northern part of Fukushima Prefecture. The following expected major pathways of 137 Cs export and diffusion were investigated: 1) transportation of dissolved and particulate or colloidal forms via hydrological processes within a forested catchment and export dynamics through the stream, and 2) diffusion through the food web in terrestrial and aquatic ecosystems of forests. Preliminary findings indicated the following: 1) Most of the 137 Cs was discharged as suspended matter. High water flow generated by storm acted to accelerate the transportation of 137 Cs from the forested catchments. Thus, the estimation of 137 Cs export requires precise evaluation of the high flow acceleration during storm events; 2) Because litter and its detritus may form the biggest pool of 137 Cs in the forested ecosystem, 137 Cs diffusion occurs more rapidly through the detritus food chain than the grazing food chain. Most predators have already ingested 137 Cs, particularly in aquatic environments. An urgent question that needs to be addressed is when and how 137 Cs diffuses through grazing food chains and how rapidly this process occurs. To elucidate or to be able to predict these phenomena, the mechanisms of 137 Cs release from litter and soil's organic matter

Climate change impact on the discharge in meso-scale catchments and consequences for the hydropower-production in Switzerland

Science.gov (United States)

Rössler, Ole; Hänggi, Pascal; Köplin, Nina; Meyer, Rapahel; Schädler, Bruno; Weingartner, Rolf

2013-04-01

The potential effect of climate change on hydrology is the acceleration of the hydrological cycle that in turn will likely cause changes in the discharge regime. As a result, socio-economic systems (e.g., tourism, hydropower industry) may be drastically affected. In this study, we comprehensively analyzed the effect of climate change on different hydrological components like mean and low-flow levels, and drought stress in mesoscale catchments of Switzerland. In terms of mean flows approx. 200 catchments in Switzerland were simulated for the reference period 1984-2005 using the hydrological model PREVAH and projection for near (2025-2046) and far future (2074-2095) are based on delta-change values of 10 ENSEMBLES regional climate models assuming A1B emission scenario (CH2011 climate scenario data sets). We found seven distinct response types of catchments, each exhibiting a characteristic annual cycle of hydrologic change. A general pattern observed for all catchments, is the clearly decreasing summer runoff. Hence, within a second analysis of future discharge a special focus was set on summer low flow in a selection of 29 catchments in the Swiss Midlands. Low flows are critical as they have great implications on water usage and biodiversity. We re-calibrated the hydrological model PREVAH with a focus on base-flow and gauged discharge and used the aforementioned climate data sets and simulation time periods. We found low flow situations to be very likely to increase in both, magnitude and duration, especially in central and western Switzerland plateau. At third, the drought stress potential was analyzed by simulating the soil moisture level under climate change conditions in a high mountain catchment. We used the distributed hydrological model WaSiM-ETH for this aspect as soil characteristics are much better represented in this model. Soil moisture in forests below 2000 m a.s.l. were found to be affected at most, which might have implication to their function as

Probiotic yogurt and acidified milk similarly reduce postprandial inflammation and both alter the gut microbiota of healthy, young men.

Science.gov (United States)

Burton, Kathryn J; Rosikiewicz, Marta; Pimentel, Grégory; Bütikofer, Ueli; von Ah, Ueli; Voirol, Marie-Jeanne; Croxatto, Antony; Aeby, Sébastien; Drai, Jocelyne; McTernan, Philip G; Greub, Gilbert; Pralong, François P; Vergères, Guy; Vionnet, Nathalie

2017-05-01

Probiotic yogurt and milk supplemented with probiotics have been investigated for their role in 'low-grade' inflammation but evidence for their efficacy is inconclusive. This study explores the impact of probiotic yogurt on metabolic and inflammatory biomarkers, with a parallel study of gut microbiota dynamics. The randomised cross-over study was conducted in fourteen healthy, young men to test probiotic yogurt compared with milk acidified with 2 % d-(+)-glucono-δ-lactone during a 2-week intervention (400 g/d). Fasting assessments, a high-fat meal test (HFM) and microbiota analyses were used to assess the intervention effects. Baseline assessments for the HFM were carried out after a run-in during which normal milk was provided. No significant differences in the inflammatory response to the HFM were observed after probiotic yogurt compared with acidified milk intake; however, both products were associated with significant reductions in the inflammatory response to the HFM compared with the baseline tests (assessed by IL6, TNFα and chemokine ligand 5) (Pyogurt intake (FC=-1·3, P adj=0·03), increased abundance of Bifidobacterium species after acidified milk intake (FC=1·4, P adj=0·04) and detection of Lactobacillus delbrueckii spp. bulgaricus (FC=7·0, P adjyogurt intake. Probiotic yogurt and acidified milk similarly reduce postprandial inflammation that is associated with a HFM while inducing distinct changes in the gut microbiota of healthy men. These observations could be relevant for dietary treatments that target 'low-grade' inflammation.

Abandoned Smolník mine (Slovakia – a catchment area affected by mining activities

Directory of Open Access Journals (Sweden)

Lintnerová, Otília

2008-06-01

Full Text Available Smolník is a historical Cu-mining area that was exploited from the 14th century to 1990. The Smolník mine was definitively closed and flooded in 1990–1994. Acid mine drainage discharging from the flooded mine (pH = 3.83, Fe = 542 mg/l, SO42– = 3642 mg/l, Cu = 1880 µg/l, Zn = 9599 µg/l, As = 108 mg/l acidified and contaminated the Smolník Creek water, which transported pollution into the Hnilec River catchment. The Smolník mine waste area has been used as a model area to document pollution of waters, stream sediments, and soils by metals and other toxic elements. Major goals of this complex study were to document creek water transport of the main pollutants (Fe, sulphates, Cu, Al, As, etc. in the form of suspended solids, to investigate elements mobility in common mine waste (rock and processing waste heaps and tailing impoundment and in the soil on the basis of neutralization and leach experiments. Different methodologies and techniques for sampling and chemical and mineralogical characterization of samples were used and checked to evaluate environmental risk of this abandoned mine area.

A hydroeconomic modeling framework for optimal integrated management of forest and water

Science.gov (United States)

Garcia-Prats, Alberto; del Campo, Antonio D.; Pulido-Velazquez, Manuel

2016-10-01

Forests play a determinant role in the hydrologic cycle, with water being the most important ecosystem service they provide in semiarid regions. However, this contribution is usually neither quantified nor explicitly valued. The aim of this study is to develop a novel hydroeconomic modeling framework for assessing and designing the optimal integrated forest and water management for forested catchments. The optimization model explicitly integrates changes in water yield in the stands (increase in groundwater recharge) induced by forest management and the value of the additional water provided to the system. The model determines the optimal schedule of silvicultural interventions in the stands of the catchment in order to maximize the total net benefit in the system. Canopy cover and biomass evolution over time were simulated using growth and yield allometric equations specific for the species in Mediterranean conditions. Silvicultural operation costs according to stand density and canopy cover were modeled using local cost databases. Groundwater recharge was simulated using HYDRUS, calibrated and validated with data from the experimental plots. In order to illustrate the presented modeling framework, a case study was carried out in a planted pine forest (Pinus halepensis Mill.) located in south-western Valencia province (Spain). The optimized scenario increased groundwater recharge. This novel modeling framework can be used in the design of a "payment for environmental services" scheme in which water beneficiaries could contribute to fund and promote efficient forest management operations.

Contribution of radioactive 137Cs discharge by suspended sediment, coarse organic matter, and dissolved fraction from a headwater catchment in Fukushima after the Fukushima Dai-ichi Nuclear Power Plant accident.

Science.gov (United States)

Iwagami, Sho; Onda, Yuichi; Tsujimura, Maki; Abe, Yutaka

2017-01-01

Radiocesium ( 137 Cs) migration from headwaters in forested areas provides important information, as the output from forest streams subsequently enters various land-use areas and downstream rivers. Thus, it is important to determine the composition of 137 Cs fluxes (dissolved fraction, suspended sediment, or coarse organic matter) that migrate through a headwater stream. In this study, the 137 Cs discharge by suspended sediment and coarse organic matter from a forest headwater catchment was monitored. The 137 Cs concentrations in suspended sediment and coarse organic matter, such as leaves and branches, and the amounts of suspended sediment and coarse organic matter were measured at stream sites in three headwater catchments in Yamakiya District, located ∼35 km northwest of Fukushima Dai-ichi Nuclear Power Plant (FDNPP) from August 2012 to September 2013, following the earthquake and tsunami disaster. Suspended sediment and coarse organic matter were sampled at intervals of approximately 1-2 months. The 137 Cs concentrations of suspended sediment and coarse organic matter were 2.4-49 kBq/kg and 0.85-14 kBq/kg, respectively. The 137 Cs concentrations of the suspended sediment were closely correlated with the average deposition density of the catchment. The annual proportions of contribution of 137 Cs discharge by suspended sediment, coarse organic matter, and dissolved fraction were 96-99%, 0.0092-0.069%, and 0.73-3.7%, respectively. The total annual 137 Cs discharge from the catchment was 0.02-0.3% of the deposition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Temporal variation of transit time of rainfall-runoff water and groundwater flow dynamics inferred by noble gasses concentration (SF6, CFCs) in a forested small catchment (Fukushima, Japan)

Science.gov (United States)

Sakakibara, Koichi; Tsujimura, Maki; Onda, Yuichi; Iwagami, Sho; Konuma, Ryohei; Sato, Yutaro

2016-04-01

Time variant transit time of water in catchments can fundamentally describe catchment function, controlling rainfall-runoff generation, groundwater flow pathway and water storage. Though rainstorm event has been recognized as active phase on catchment hydrology, accurate and precise time variance of water transit time and related water dynamics during rainstorm have not been well clarified yet. Here, in order to reveal temporal variation of mean transit time of groundwater and related hydrological processes in a forested small catchment during rainstorm event, periodic and intensive field observations (15 - 17th July 2015, rainfall of 100.8 mm in total) were conducted in Yamakiya district (Fukushima, Japan) from September 2014 to December 2015. Discharge volume, groundwater table and precipitation amount were measured in 10 minutes interval. Water samples were taken from groundwater, discharge water, soil water and precipitation for determination of stable isotopic compositions (δ18O, δ2H), inorganic solutes concentration and dissolved noble gasses concentration (CFC11, CFC12, CFC113, SF6) in water. Storm hydrograph and groundwater table clearly responded to rainfall event especially with more than 30 mm per day throughout monitoring period. According to SF6 concentration in water, the mean transit time of discharge water (perennial spring) showed 3 - 6.5 years in the no-rainfall period (steady state), but fluctuated from zero to 12.5 years in the rainstorm event with totally 100.8 mm (unsteady state). The mean transit time of discharge water dramatically altered from zero to 12.5 years from before to after the tentative hydrograph peak in the rising limb, indicating new water components were dominant before tentative hydrograph peak, whereas deep groundwater component with longer residence time contributed much to discharge after the tentative hydrograph peak. On the other hand, mean residence time of groundwater (water in 5 m well) ranged from 0.5 to 11.5 years

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

Implementing integrated catchment management in the Limpopo River Basin Phase 1: Situational assessment

CSIR Research Space (South Africa)

Mwenge Kahinda, Jean-Marc

2012-10-01

Full Text Available reaches of the main stem of the Limpopo River. Much of the surface water exploitation in the basin states relies on storage reservoirs built on tributary rivers. Surface water use is directed primarily to irrigated agriculture, afforestation... and the pool storages located in the A63E and A71L catchments. The riverine gallery forest (Figure 6) is an aquifer-dependent ecosystem situated on the same aquifer used by the Venetia Mine and recharged by the Limpopo River main stem. The isolated...

Community structure, life histories and secondary production of stoneflies in two small mountain streams with different degree of forest cover

Directory of Open Access Journals (Sweden)

Pavel Beracko

2015-10-01

Full Text Available Our study examines community structure and nymphal biology (life cycles and secondary production of stoneflies in two adjacent mountain streams with different degree of forest cover in the Prosiečanka River Basin (Chočské Vrchy Mts., West Carpathians. One of the streams has non-forested catchment, converted to meadows and pastures, while the other one has catchment with 60% covered by spruce forest. Differences in forest cover and in thermal regime of the streams were reflected by the difference of stonefly communities at their structural and functional level. Species Nemoura cinerea and Leuctra aurita created stonefly assemblage in non-forested stream, whereas Nemoura cinerea also occurred in naturally forested stream together with species Leuctra armata, Leuctra nigra, Leuctra prima, Siphonoperla neglecta and Arcynopteryx dichroa. All examined species had maximally annual life cycle and in eudominant species Nemoura cinerea one month shift was found in nymphal hatching and adult emergence between streams. Total secondary production of stoneflies in undisturbed stream (126.46 mg DW m-2 y-1 was more than two times higher than the production in non-forested stream (47.39 mg DW m-2 y-1. 

Analyzing the hydrological impact of afforestation and tree species in two catchments with contrasting soil properties using the spatially distributed model MIKE SHE SWET

DEFF Research Database (Denmark)

Sonnenborg, Torben Obel; Christiansen, Jesper Riis; Pang, Bo

2017-01-01

afforestation or forest conversion impacts the water resource at the catchment scale. We hypothesize that the groundwater formation and streamflow is increased when water consuming conifers are replaced with the less consumptive broadleaf tree species. To test this a distributed hydrological model...

Chalk Catchment Transit Time: Unresolved Issues

Energy Technology Data Exchange (ETDEWEB)

Darling, W. G.; Gooddy, D. C. [British Geological Survey, Crowmarsh Gifford, Wallingford, Oxfordshire (United Kingdom); Barker, J. A. [School of Civil Engineering and the Environment, University of Southampton, Southampton (United Kingdom); Robinson, M. [Centre for Ecology and Hydrology, Crowmarsh Gifford, Wallingford, Oxfordshire (United Kingdom)

2013-07-15

The mean transit time (MTT) of a catchment is the average residence time of water from rainfall to river outflow at the foot of the catchment. As such, MTT has important water quality as well as resource implications. Many catchments worldwide have been measured for MTT using environmental isotopes, yet the Chalk, an important aquifer in NW Europe, has received little attention in this regard. The catchment of the River Lambourn in southern England has been intermittently studied since the 1960s using isotopic methods. A tritium peak measured in the river during the 1970s indicates an apparent MTT of {approx}15 years, but the thick unsaturated zone (average {approx}50 m) of the catchment suggests that the MTT should be much greater because of the average downward movement through the Chalk of {approx}1 m/a consistently indicated by tritium and other tracers. Recent work in the catchment using SF{sub 6} as a residence time indicator has given groundwater ages in the narrow range 11-18 yrs, apparently supporting the river tritium data but in conflict with the unsaturated zone data even allowing for a moderate proportion of rapid bypass flow. The MTT of the catchment remains unresolved for the time being. (author)

Diffusion and export dynamics of "1"3"7Cs deposited on the forested area in Fukushima after the nuclear power plant accident in March 2011. Preliminary results

International Nuclear Information System (INIS)

Ohte, Nobuhito; Iseda, Kohei; Tanoi, Keitaro; Murakami, Masashi; Suzuki, Takahiro; Ishii, Nobuyoshi

2013-01-01

A massive amount of radioactive substances, including cesium-137 ("1"3"7Cs), emitted from the disabled nuclear power plant, has been deposited on the forested areas in the northeastern region of Honshu Island, Japan after the Fukushima Daiichi nuclear power plant accident. Forests in these regions are particularly important, not only for the forest products industry but also for source areas of drinking water and for residential environments. To clarify the mechanisms of diffusion and export of "1"3"7Cs deposited on the forested ecosystem, we initiated intensive field observations in a small catchment that included forest and farmlands. Specifically, we were interested in the Kami-Oguni River catchment that is located in the northern part of Fukushima Prefecture. The following expected major pathways of "1"3"7Cs export and diffusion were investigated: 1) transportation of dissolved and particulate or colloidal forms via hydrological processes within a forested catchment and export dynamics through the stream, and 2) diffusion through the food web in terrestrial and aquatic ecosystems of forests. Preliminary findings indicated the following: 1) Most of the "1"3"7Cs was discharged as suspended matter. High water flow generated by storm acted to accelerate the transportation of "1"3"7Cs from the forested catchments. Thus, the estimation of "1"3"7Cs export requires precise evaluation of the high flow acceleration during storm events; 2) Because litter and its detritus may form the biggest pool of "1"3"7Cs in the forested ecosystem, "1"3"7Cs diffusion occurs more rapidly through the detritus food chain than the grazing food chain. Most predators have already ingested "1"3"7Cs, particularly in aquatic environments. An urgent question that needs to be addressed is when and how "1"3"7Cs diffuses through grazing food chains and how rapidly this process occurs. To elucidate or to be able to predict these phenomena, the mechanisms of "1"3"7Cs release from litter and soil

Overland flow connectivity in a forest plantation before and after tree thinning (Tochigi Prefecture, central Japan)

Science.gov (United States)

López-Vicente, Manuel; Onda, Yuichi; Sun, Xinchao; Kato, Hiroaki; Gomi, Takashi; Hiraoka, Marino

2016-04-01

Overland flow connectivity is a key factor to understand the redistribution dynamics of sediments, nutrients, radiotracers, etc., in the different compartments at channel, hillslope and catchment scales. Human organization of landscape elements has a significant control on runoff and soil redistribution processes. Construction of trails, forest roads and firewalls influence runoff connectivity (RC) in forested catchments. In this study we simulated RC in two forested catchments, called K2 (19.3 ha) and K3 (13.6 ha), located on the Mount Karasawa, in the Tochigi Prefecture in central Japan. Forest plantation includes Japanese cypress and cedar and covers 59% of the total area. Native broad-leaved trees (28%) and mixed forest occupy the rest of the study area. We selected the Index of runoff and sediment Connectivity (IC) of Borselli et al. (2008) to simulate three temporal scenarios: i) Sc-2011, before tree thinning (TT); ii) Sc-2012 after TT in most part of the forest plantation in K2 (32% of the total area); and iii) Sc-2013 after TT in some areas of the K3 catchment, affecting 38% of the total area. The study areas were defined from the coalescence point (139⁰ 36' 04" E, 36⁰ 22' 03" N) of both catchments upslope. Elevation ranges from 75 to 287 m a.s.l. and the mean slope steepness is of 67 and 65% in K2 and K3. Three different high resolution DEM-LiDAR maps at 0.5 x 0.5 m of cell size were used to run the IC model in each scenario. The permanent streams in the study area have a total length of 2123 m. The mean C-RUSLE factor was of 0.0225 in Sc-2011 and 21% and 25% higher in Sc-2012 and Sc-2013. The total length of the landscape linear elements incremented from 2482 m in Sc-2011 to 3151 m in Sc-2012 and Sc-2013 due to the construction of new skid trails in K2. The mean RC in the study area was of -4.536 in Sc-2011 and increased 7.4% and 8.9% in the Sc-2012 and Sc-2013, respectively, due to the tree thinning operations and the construction of new skid trails

An Eco-hydrologic Assessment of Small Experimental Catchments with Various Land Uses within the Panama Canal Watershed: Agua Salud Project

Science.gov (United States)

Crouch, T. D.; Ogden, F. L.; Stallard, R. F.; Smithsonian Tropical Research Institute, Panama Canal Watershed Experiment, Agua Salud Project

2010-12-01

Hydrological processes in the humid tropics are poorly understood and an important topic when it comes to water management in the seasonal tropics. The Smithsonian Tropical Research Institute, Panama Canal Watershed Experiment, Agua Salud Project, seeks to understand these processes and quantify the long-term effects of different land cover and uses across the Panama Canal Watershed. One of the project’s main objectives is to understand how reforestation effects seasonal stream flows. To meet this objective, a baseline characterization of hydrology on the small catchment scale is being assessed across different land uses typical in rural Panama. The small experimental catchments are found within Panama’s protected Soberania National Park and the adjacent headwaters of the Agua Salud and Mendoza Rivers, all of which are part of the greater Panama Canal Watershed. The land uses being monitored include a variety of control catchments as well as treated pasture sites. The catchments used for this study include a mature old regrowth forest, a 50% deforested or mosaic regrowth site, an active pasture and a monoculture invasive grass site (saccharum spontaneum) as experimental controls and two treated catchments that were recently abandoned pastures converted to teak and native species timber plantations. Installed instrumentation includes a network of rain gauges, v-notched weirs, atmometers, an eddy covariance system and an assortment of meteorological and automated geochemical sampling systems. Spatial, rainfall, runoff and ET data across these six geologically and topographically similar catchments are available from 2009 and 2010. Classic water balance and paired catchment techniques were used to compare the catchments on an annual, seasonal, and event basis. This study sets the stage for hydrologic modeling and for better understanding the effects of vegetation and land-use history on rainfall-runoff processes for the Agua Salud Project and Panama Canal

The Impact of Forest Density on Forest Height Inversion Modeling from Polarimetric InSAR Data

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Changcheng Wang

2016-03-01

Full Text Available Forest height is of great significance in analyzing the carbon cycle on a global or a local scale and in reconstructing the accurate forest underlying terrain. Major algorithms for estimating forest height, such as the three-stage inversion process, are depending on the random-volume-over-ground (RVoG model. However, the RVoG model is characterized by a lot of parameters, which influence its applicability in forest height retrieval. Forest density, as an important biophysical parameter, is one of those main influencing factors. However, its influence to the RVoG model has been ignored in relating researches. For this paper, we study the applicability of the RVoG model in forest height retrieval with different forest densities, using the simulated and real Polarimetric Interferometric SAR data. P-band ESAR datasets of the European Space Agency (ESA BioSAR 2008 campaign were selected for experiments. The test site was located in Krycklan River catchment in Northern Sweden. The experimental results show that the forest density clearly affects the inversion accuracy of forest height and ground phase. For the four selected forest stands, with the density increasing from 633 to 1827 stems/Ha, the RMSEs of inversion decrease from 4.6 m to 3.1 m. The RVoG model is not quite applicable for forest height retrieval especially in sparsely vegetated areas. We conclude that the forest stand density is positively related to the estimation accuracy of the ground phase, but negatively correlates to the ground-to-volume scattering ratio.

Reliance on shallow soil water in a mixed-hardwood forest in central Pennsylvania.

Science.gov (United States)

Gaines, Katie P; Stanley, Jane W; Meinzer, Frederick C; McCulloh, Katherine A; Woodruff, David R; Chen, Weile; Adams, Thomas S; Lin, Henry; Eissenstat, David M

2016-04-01

We investigated depth of water uptake of trees on shale-derived soils in order to assess the importance of roots over a meter deep as a driver of water use in a central Pennsylvania catchment. This information is not only needed to improve basic understanding of water use in these forests but also to improve descriptions of root function at depth in hydrologic process models. The study took place at the Susquehanna Shale Hills Critical Zone Observatory in central Pennsylvania. We asked two main questions: (i) Do trees in a mixed-hardwood, humid temperate forest in a central Pennsylvania catchment rely on deep roots for water during dry portions of the growing season? (ii) What is the role of tree genus, size, soil depth and hillslope position on the depth of water extraction by trees? Based on multiple lines of evidence, including stable isotope natural abundance, sap flux and soil moisture depletion patterns with depth, the majority of water uptake during the dry part of the growing season occurred, on average, at less than ∼60 cm soil depth throughout the catchment. While there were some trends in depth of water uptake related to genus, tree size and soil depth, water uptake was more uniformly shallow than we expected. Our results suggest that these types of forests may rely considerably on water sources that are quite shallow, even in the drier parts of the growing season. © The Author 2015. Published by Oxford University Press.

Chemical composition and phosphorus fractionation of sediments in the Bohemian Forest lakes

Czech Academy of Sciences Publication Activity Database

Borovec, Jakub

2000-01-01

Roč. 4, č. 4 (2000), s. 179-184 ISSN 1211-7420. [Acidified Lakes in the Bohemian/Bavarian Forest - History, Present and Future. Č. Budějovice, 21.03.2000-23.03.2000] R&D Projects: GA ČR GA206/97/0072; GA ČR GA206/98/0727; GA ČR GA206/00/0063 Grant - others:EU(XE) MOLAR:ENV4-CT95-0007; EU(XE) EMERGE:EVK1-CT-1999-00032 Institutional research plan: CEZ:AV0Z6017912; CEZ:MSM123100004 Subject RIV: CB - Analytical Chemistry, Separation

Preliminary estimating the contemporary sedimentation trend in dry valley bottoms of first-order catchments of different landscape zones of the Russian Plain using the 137Cs as a chronomarker

Science.gov (United States)

Sharifullin, A.; Gusarov, A.; Gafurov, A.; Essuman-Quainoo, B.

2018-01-01

A general trend of erosion processes over the last 50-60 years can be estimated by dating sediments washed off from arable lands and accumulated in the first-order dry valleys bottoms. Three small (first-order) catchments were chosen as objects of the study. They are located, respectively, in the southern part of the taiga zone, the zone of temperate broad-leaf forests and the forest-steppe zone of the Russian Plain. To date the sediments accumulated in the bottoms the radioactive caesium-137 (137Cs) of global (since 1954) and Chernobyl origin (1986) had been used as a chronomarker. The average (for all the catchments) sedimentation rates during the global 137Cs fallout period (1963(1954)-1986) are at least 0.88-2.71 cm per year.For the period that has passed since the Chernobyl accident (1986-2015(2016)) the average rates were 0.15-1.07 cm per year. The greatest reduction in the sedimentation rates is observed in the subzone of the southern taiga, the lowest one is in the forest-steppe zone of the Russian Plain. The main reason for such significant reduction in the rates of sedimentation of the soil erosion products in the dry valley bottoms was a reduction of surface runoff within the catchments during a snowmelt period, as well as crop-rotation changes there.

Snowmelt in a High Latitude Mountain Catchment: Effect of Vegetation Cover and Elevation

Science.gov (United States)

Pomeroy, J. W.; Essery, R. L.; Ellis, C. R.; Hedstrom, N. R.; Janowicz, R.; Granger, R. J.

2004-12-01

The energetics and mass balance of snowpacks in the premelt and melt period were compared from three elevation bands in a high latitude mountain catchment, Wolf Creek Research Basin, Yukon. Elevation is strongly correlated with vegetation cover and in this case the three elevation bands (low, middle, high) correspond to mature spruce forest, dense shrub tundra and sparse tundra (alpine). Measurements of radiation, ground heat flux, snow depth, snowfall, air temperature, wind speed were made on a half-hourly basis at the three elevations for a 10 year period. Sondes provided vertical gradients of air temperature, humidity, wind speed and air pressure. Snow depth and density surveys were conducted monthly. Comparisons of wind speed, air temperature and humidity at three elevations show that the expected elevational gradients in the free atmosphere were slightly enhanced just above the surface canopies, but that the climate at the snow surface was further influenced by complex canopy effects. Premelt snow accumulation was strongly affected by intercepted snow in the forest and blowing snow sublimation in the sparse tundra but not by the small elevational gradients in snowfall. As a result the maximum premelt SWE was found in the mid-elevation shrub tundra and was roughly double that of the sparse tundra or forest. Minimum variability of SWE was observed in the forest and shrub tundra (CV=0.25) while in the sparse tundra variability doubled (CV=0.5). Snowmelt was influenced by differences in premelt accumulation as well as differences in the net energy fluxes to snow. Elevation had a strong effect on the initiation of melt with the forest melt starting on average 16 days before the shrub tundra and 19 days before the sparse tundra. Mean melt rates showed a maximum in middle elevations and increased from 860 kJ/day in the forest to 1460 kJ/day in the sparse tundra and 2730 kJ/day in the shrub tundra. The forest canopy reduced melt while the shrub canopy enhanced it

Dissolved and particulate nutrient export from rural catchments: a case study from Luxembourg.

Science.gov (United States)

Salvia-Castellví, Mercè; Iffly, Jean François; Borght, Paul Vander; Hoffmann, Lucien

2005-05-15

Nutrient enrichment of freshwaters continues to be one of the most serious problems facing the management of surface waters. Effective remediation/conservation measures require accurate qualitative and quantitative knowledge of nutrient sources, transport mechanisms, transformations and annual dynamics of different nitrogen (N) and phosphorus (P) forms. In this paper, nitrate (NO3-N), soluble reactive phosphorus (SRP) and total phosphorus (TP) concentrations and loads are presented for two adjacent rural basins of 306 km2 and 424 km2, and for five sub-basins differing in size (between 1 km2 and 33 km2), land use (extent of forest cover between 20% and 93%) and household pressure (from 0 to 40 people/km2) with the aim of studying the influence of land use and catchment size on nutrient exports. The studied catchments are all situated on Devonian schistous substrates in the Ardennes region (Belgium-Luxembourg), and therefore have similar hydrological regimes. As the study period could not be the same for all basins, annual export coefficients were corrected with the 25 years normalized discharge of the Sure River: two regression analyses (for dry and humid periods) relating monthly nutrient loads to monthly runoff were used to determine correction factors to be applied to each parameter and each basin. This procedure allows for the comparing annual export coefficients from basins sampled in different years. Results show a marked seasonal response and a large variability of NO3-N export loads between forested (4 kg N ha-1 year-1), agricultural (27-33 kg N ha-1 year-1) and mixed catchments (17-22 kg N ha-1 year-1). For SRP and TP, no significant agricultural impact was found. Land and bank erosion control the total P massflow in the studied catchments (0.4-1.3 kg P ha-1 year-1), which is mostly in a particulate form, detached and transported during storm events. Soluble reactive P fluxes ranged between 10% and 30% of the TP mass, depending on the importance of point

Lateral water flux in the unsaturated zone: A mechanism for the formation of spatial soil heterogeneity in a headwater catchment

Science.gov (United States)

John P. Gannon; Kevin J. McGuire; Scott W. Bailey; Rebecca R. Bourgault; Donald S. Ross

2017-01-01

Measurements of soil water potential and water table fluctuations suggest that morphologically distinct soils in a headwater catchment at the Hubbard Brook Experimental Forest in New Hampshire formed as a result of variations in saturated and unsaturated hydrologic fluxes in the mineral soil. Previous work showed that each group of these soils had distinct water table...

Gastro-oesophageal reflux disease and dental erosions in adults: influence of acidified food intake and impact on quality of life.

Science.gov (United States)

Milani, Daiane C; Venturini, Ana Paula C; Callegari-Jacques, Sidia M; Fornari, Fernando

2016-07-01

Gastro-oesophageal reflux disease (GORD) and dental erosions (DE) have an established association. We assessed whether GORD is associated with DE controlling for acidified food intake and their relationships with quality of life (QOL). In this cross-sectional study, 419 adult patients who sought dentistry consultation were considered eligible. Patients responded to questionnaires for GORD symptoms, acidified food ingestion and World Health Organization quality of life (WHOQOL Bref), followed by an oral examination, in which DE were characterized according to the Smith & Knight criteria. A total of 417 patients were included (43.8±13.7 years; 68.8% women). There were 143 patients with GORD (34.3%) and 274 controls without GORD. The prevalence of DE was higher in GORD patients compared with the controls (25.9 vs. 17.2%; P=0.041). GORD was associated with DE after adjusting for acidified food intake (P=0.035), with a prevalence ratio of 1.52 (0.95 confidence interval 1.03-2.22). The WHOQOL Bref score was significantly lower in the presence of GORD [median 17.2 (GORD-DE-) vs. 15.4 (GORD+DE+); P<0.01], irrespective of DE. In adults examined in a referential dentistry centre in South America, DE were prevalent and significantly associated with GORD. This association was independent of the intake of acidified food in our study. Impairment in QOL was observed in GORD patients irrespective of the presence of DE.

Effects of simulated rain acidified with sulfuric acid on host-parasite interactions

Science.gov (United States)

D. S. Shriner

1976-01-01

Wind-blown rain, rain splash, and films of free moisture play important roles in the epidemiology of many plant diseases. The effects of simulated rain acidified with sulfuric acid were studied on several host-parasite systems. Plants were exposed, in greenhouse or field, to simulated rain of pH 3.2 ? 0.1 or pH 6.0 ? 0.2. Simulated "rain" of pH 3.2 resulted...

Effects of runoff sensitivity and catchment characteristics on regional actual evapotranspiration trends in the conterminous US

International Nuclear Information System (INIS)

Jung, Il Won; Chang, Heejun; Risley, John

2013-01-01

An understanding of the role of hydro-climatic and geographic regimes on regional actual evapotranspiration (AET) change is essential to improving our knowledge on predicting water availability in a changing climate. This study investigates the relationship between AET change for a 60 year period (1951–2010) and the runoff sensitivity in 255 undisturbed catchments over the US. The runoff sensitivity to climate change is simply defined as the relative magnitude between runoff and precipitation changes with time. Runoff sensitivity can readily explain the conflicting directions of AET changes under similar precipitation change. Under increasing precipitation, AET decreases when runoff is increasing more rapidly than precipitation based on the water balance. Conversely, AET increases when runoff is decreasing more rapidly than precipitation. This result indicates that runoff sensitivity to climate change is a key factor for understanding regional water availability change at the catchment scale. In addition, a stepwise multiple regression analysis and a geographically weighted regression analysis show that the portion of evergreen forest and the mean elevation of a catchment may play a secondary role in the spatial pattern of the AET change, and the relative importance of such explanatory variables may change over space. (letter)

Coupling Evapotranspiration and Watershed Storage to Assess the Impact of Forest Disturbance on Low Flows

Science.gov (United States)

Brena Naranjo, J.; Stahl, K.; Weiler, M.

2009-05-01

Low flows are important for water-supply planning and design, and maintenance of quantity and quality of water for irrigation, recreation, and fish and wildlife conservation. There have been concerns recently that climate warming and land cover changes due to an unprecedented pine beetle epidemic in British Columbia, Canada, may cause a deterioration of water quantity during low flow periods and at certain times may become a hazard to ecosystem and to water management schemes. A study to characterize the sensitivity of the low flow regimes was performed for several mainly forested catchments located within the Fraser River basin. Here, summer low flows are maintained through the release of water from groundwater and riparian storage, lakes and wetlands, but are reduced by high evapotranspiration rates in the catchments. Since evapotranspiration in British Columbia accounts around 40% of the precipitation, the first part of this work was focused on the assessment of the relationship between the potential evapotranspiration (PET) and the actual evapotranspiration (AET) for undisturbed and disturbed landscapes which is expected to influence the hydrological behavior during the low-flow season. Through its influence on evapotranspiration, forest age appears to play an important role in the water balance. The second part of the study implemented a forest age dependent calculation of AET into a parsimonious water balance model, which was applied to simulate the sensitivity of the flow regimes of 15 non regulated watersheds to changes after the beginning of the pine beetle epidemic at a large scale. The model input was derived from disaggregated gridded 30-year climate normals. Since the geologic and topographic properties are first order controls on water storage and release of the examined catchments a framework for regionalization of these properties into ungauged catchments was developed. Furthermore, the interaction between forest disturbance and evapotranspiration

Influence of landscape mosaic on streamflow of a peri-urban catchment under Mediterranean climate

Science.gov (United States)

Ferreira, Carla; Walsh, Rory; Ferreira, António

2017-04-01

Peri-urban areas tend to be characterized by patchy landscape mosaics of different land-uses. Although the impact of land-use changes on catchment hydrology have been widely investigated, the impact of mixed land-use patterns on the streamflow of peri-urban areas is still poorly understood. This study aims to (i) explore and quantify streamflow delivery from sub-catchments characterized by distinct landscape mosaics; (ii) assess the impact of different urbanization styles on hydrograph properties; and (iii) explore the influence of urbanization type on flow connectivity and stream discharge. The study was carried out in Ribeira dos Covões, a small (6.2km2) peri-urban catchment in central Portugal. The climate is Mediterranean, with a mean annual rainfall of 892mm. Catchment geology comprises sandstone (56%), limestone (41%) and alluvial deposits (3%). Soils developed on sandstone are generally deep (>3m) Fluvisols and Podsols, whereas on limestone the Leptic Cambisols are typically shallow (blocks and of high population density (9900 inhabitants km-2). The study uses hydrological data recorded over three hydrological years, starting in November 2010, in a monitoring network comprising eight streamflow gauging stations (instrumented with water level recorders) and five rainfall gauges. The gauging stations provide information on the discharge response to rainstorms of the catchment outlet and upstream sub-catchments of different size, urban pattern (in terms of percentage urban land-use and impervious area, distance to the stream network, and storm water management), and lithology (either sandstone or limestone). Annual storm runoff coefficients were lowest (13.7%) in catchments dominated by forest (>80%) and greatest (17.3-17.6%) in the most urbanized sub-catchments (49-53% urban). Impervious area seems to control streamflow particularly during dry periods. Winter runoff (streamflow per unit area) was 2-4 times higher than summer runoff in highly urbanized areas

A comparative analysis of forest cover and catchment water yield relationships in northern China

Science.gov (United States)

Shuai Wang; Bo-Jie Fu; Chan-Sheng He; Ge Sun; Guang-Yao Gao

2011-01-01

During the past few decades, China has implemented several large-scale forestation programs that have increased forest cover from 16.0% in the 1980s to 20.4% in 2009. In northern China, water is the most sensitive and limiting ecological factor. Understanding the dynamic interactions between forest ecosystems and water in different regions is essential for maximizing...

Development of catchment research, with particular attention to Plynlimon and its forerunner, the East African catchments

Science.gov (United States)

Blackie, J. R.; Robinson, M.

2007-01-01

Dr J.S.G. McCulloch was deeply involved in the establishment of research catchments in East Africa and subsequently in the UK to investigate the hydrological consequences of changes in land use. Comparison of these studies provides an insight into how influential his inputs and direction have been in the progressive development of the philosophy, the instrumentation and the analytical techniques now employed in catchment research. There were great contrasts in the environments: tropical highland (high radiation, intense rainfall) vs. temperate maritime (low radiation and frontal storms), contrasting soils and vegetation types, as well as the differing social and economic pressures in developing and developed nations. Nevertheless, the underlying scientific philosophy was common to both, although techniques had to be modified according to local conditions. As specialised instrumentation and analytical techniques were developed for the UK catchments many were also integrated into the East African studies. Many lessons were learned in the course of these studies and from the experiences of other studies around the world. Overall, a rigorous scientific approach was developed with widespread applicability. Beyond the basics of catchment selection and the quantification of the main components of the catchment water balance, this involved initiating parallel process studies to provide information on specific aspects of catchment behaviour. This information could then form the basis for models capable of extrapolation from the observed time series to other periods/hydrological events and, ultimately, the capability of predicting the consequences of changes in catchment land management to other areas in a range of climates.

Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

Science.gov (United States)

Moset, Veronica; Ottosen, Lars Ditlev Mørck; Xavier, Cristiane de Almeida Neves; Møller, Henrik Bjarne

2016-05-15

Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM. Important enhancement of methane (CH4) yield and solid reductions were observed in the thermophilic one-step CSTR working with 10% AcCM. However, a higher inclusion level of AcCM (20%) caused volatile fatty acid accumulation in the reactor and a more than 30% reduction in CH4 production. In terms of CH4 production, when 10% of AcCM was co-digested with 90% of CM, the two-step anaerobic co-digestion yielded less than the single step. During the first step of the two-step CSTR process, acidogenesis and a partial sulfate reduction were achieved. However, sulfide stripping between the first and the second step must be promoted in order to advance this technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Scale dependence of the episodic hydrochemical response of nested catchments at Plynlimon

Directory of Open Access Journals (Sweden)

H. J. Foster

1997-01-01

Full Text Available Previous monitoring of the surface water chemistry of the forested catchments at Plynlimon has concentrated on weekly measurements. Hence, peak values and details of the rapid changes in chemistry occurring during events tend to be missed, particularly for smaller catchments. Knowledge of the detailed hydrochemical response is necessary to predict effects on stream ecology and to quantify processes occurring within the catchment. This information is vital if the likely impacts of changes in landuse and pollutant input on episodic hydrochemical variations are to be modelled. A summary of daily and three-hourly chemistry for the River Severn headwaters at Plynlimon, central Wales is presented. Data are from the summer and autumn of 1995 and the winter and summer of 1996. The effects of antecedent conditions, soiltype, landuse and groundwater and tributary inflow on stream episodic hydrochemical response are discussed for a range of spatial scales, including first, second and third order streams. Detailed information on the chemical changes due to a discrete groundwater inflow into the bed of one stream shows that, during episodes, its influence on stream chemistry is overridden by that of event water. A comparison of drainage ditch chemistry with main stream chemistry during storm events is used to consider the importance of tributary inflow at these times. The contrast in results between sites is assessed, to evaluate the effects of clearfelling and soil type on stream event chemistry.

SOILS VULNERABILITY OF CATCHMENT ALMAŞ AT GEOMORPHOLOGIC CONTEMPORARY PROCESSES

Directory of Open Access Journals (Sweden)

MĂDĂLINA-IOANA RUS

2015-03-01

Full Text Available Soils vulnerability of the Catchment Almas geomorphologic processes. Almas Basin, signed lower lithologic Miocene soils deposits, shows six classes: Cernisols, Cambisols, Luvisols, Hydrosols, Pelisols, Protosols (after SRTS, 2003. The largest share is attributed to Luvisols class (60%, followed by undeveloped soil represented by Protosols and Antrisols (15%, followed by the remaining classes with lower weights: Cambisols (13%, Cernisols (7%, Pelisols (4%, Hydrosols (1%. Contemporary geomorphological processes (surface and deep erosion, mass movements change agricultural areas and forest ratio or flow out of economic network tens of hectares annually. Soil vulnerability to the manifestation of these processes is expressed by disturbing soil horizons, coastal springs appearance and growth of the adjoining excess moisture, soil sealing productive by dropping or by alienation.

Establishment of experimental catchments to quantify water use by different vegetation types / Estabelecimento de microbacias experimentais para quantificar uso de água por diferentes tipos de vegetação

Directory of Open Access Journals (Sweden)

Almeida Auro Campi

2010-10-01

Full Text Available AbstractThis paper describes the procedure developed to select representative experimental catchments to quantify water use and water use efficiency of different vegetation types. We combined freely available information such as LANDSAT satellite images, digital elevation model, Google Earth images, streamflow and rainfall historical data, and soils and vegetation data to select the experimental catchments. Once these catchments were indentified, sub-catchments with different vegetation were delineated, which were used to define the distribution and installation of the instrumentation. Forty eight catchments and respective sub-catchments of Tasmania in Australia were analyzed and only two catchments were identified as ideal for the purposes of quantifying and comparing the historic and current water use by Eucalyptus plantation, native forest and pasture. We choose one catchment and created four experimental and instrumented sub-catchments with the following predominant land use: Eucalyptus nitens, native forest and pasture. ResumoO presente artigo descreve o procedimento desenvolvido para selecionar microbacias representativas para quantificar o uso de água e a eficiência do uso de água de diferentes tipos de vegetação. Foram combinadas informações disponíveis sem custo tais como: imagens de satélite LANDSAT, modelo digital do terreno, imagens de Google Earth, escoamento superficial e dados históricos de precipitação pluviométrica, tipos de solos e cobertura vegetal para a seleção de microbacias experimentais. Uma vez identificadas as microbacias, sub-microbacias com diferente tipos de vegetação foram delineadas, as quais foram usadas para definir a distribuição e instalação de instrumentação. Foram analisadas quarenta e oito microbacias e respectivas sub-microbacias na Tasmânia na Austrália e somente duas microbacias foram identificadas como ideais para o propósito de quantificar e comparar o histórico e atual uso de

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

Using Tree Detection Algorithms to Predict Stand Sapwood Area, Basal Area and Stocking Density in Eucalyptus regnans Forest

Directory of Open Access Journals (Sweden)

Dominik Jaskierniak

2015-06-01

Full Text Available Managers of forested water supply catchments require efficient and accurate methods to quantify changes in forest water use due to changes in forest structure and density after disturbance. Using Light Detection and Ranging (LiDAR data with as few as 0.9 pulses m−2, we applied a local maximum filtering (LMF method and normalised cut (NCut algorithm to predict stocking density (SDen of a 69-year-old Eucalyptus regnans forest comprising 251 plots with resolution of the order of 0.04 ha. Using the NCut method we predicted basal area (BAHa per hectare and sapwood area (SAHa per hectare, a well-established proxy for transpiration. Sapwood area was also indirectly estimated with allometric relationships dependent on LiDAR derived SDen and BAHa using a computationally efficient procedure. The individual tree detection (ITD rates for the LMF and NCut methods respectively had 72% and 68% of stems correctly identified, 25% and 20% of stems missed, and 2% and 12% of stems over-segmented. The significantly higher computational requirement of the NCut algorithm makes the LMF method more suitable for predicting SDen across large forested areas. Using NCut derived ITD segments, observed versus predicted stand BAHa had R2 ranging from 0.70 to 0.98 across six catchments, whereas a generalised parsimonious model applied to all sites used the portion of hits greater than 37 m in height (PH37 to explain 68% of BAHa. For extrapolating one ha resolution SAHa estimates across large forested catchments, we found that directly relating SAHa to NCut derived LiDAR indices (R2 = 0.56 was slightly more accurate but computationally more demanding than indirect estimates of SAHa using allometric relationships consisting of BAHa (R2 = 0.50 or a sapwood perimeter index, defined as (BAHaSDen½ (R2 = 0.48.

A spatially distributed isotope sampling network in a snow-dominated catchment for the quantification of snow meltwater

Science.gov (United States)

Rücker, Andrea; Boss, Stefan; Von Freyberg, Jana; Zappa, Massimiliano; Kirchner, James

2017-04-01

In mountainous catchments with seasonal snowpacks, river discharge in downstream valleys is largely sustained by snowmelt in spring and summer. Future climate warming will likely reduce snow volumes and lead to earlier and faster snowmelt in such catchments. This, in turn, may increase the risk of summer low flows and hydrological droughts. Improved runoff predictions are thus required in order to adapt water management to future climatic conditions and to assure the availability of fresh water throughout the year. However, a detailed understanding of the hydrological processes is crucial to obtain robust predictions of river streamflow. This in turn requires fingerprinting source areas of streamflow, tracing water flow pathways, and measuring timescales of catchment storage, using tracers such as stable water isotopes (18O, 2H). For this reason, we have established an isotope sampling network in the Alptal, a snowmelt-dominated catchment (46.4 km2) in Central-Switzerland, as part of the SREP-Drought project (Snow Resources and the Early Prediction of hydrological DROUGHT in mountainous streams). Precipitation and snow cores are analyzed for their isotopic signature at daily or weekly intervals. Three-week bulk samples of precipitation are also collected on a transect along the Alptal valley bottom, and along an elevational transect perpendicular to the Alptal valley axis. Streamwater samples are taken at the catchment outlet as well as in two small nested sub-catchments (automatic snow lysimeter system was developed, which also facilitates real-time monitoring of snowmelt events, system status and environmental conditions (air and soil temperature). Three lysimeter systems were installed within the catchment, in one forested site and two open field sites at different elevations, and have been operational since November 2016. We will present the isotope time series from our regular sampling network, as well as initial results from our snowmelt lysimeter sites. Our

Hydrolysis-precipitation studies of aluminum (III) solutions. I. Titration of acidified aluminum nitrate solutions

NARCIS (Netherlands)

Vermeulen, A.C.; Geus, John W.; Stol, R.J.; Bruyn, P.L. de

Acidified aluminum nitrate solutions were titrated with alkali (NaOH or KOH) over a temperature range of 24°C to 90°C. A homogeneous distribution of added base was achieved by: (i) in situ decomposition of urea (90°C); and (ii) a novel method involving injection through a capillary submerged in the

Effects of exogenous salinity (NaCl) gradient on Cd release in acidified contaminated brown soil

Science.gov (United States)

Zhang, Lina; Rong, Yong; Mao, Li; Gao, Zhiyuan; Liu, Xiaoyu; Dong, Zhicheng

2018-02-01

Taking acidified Cd contaminated brown soil in Yantai as the research object, based on different exogenous salinity (NaCl) gradient (0%, 0.3%, 0.6%, 0.9%, 1.5%, 2% and 5%), indoor simulation experiments of Cd release were carried out after field investigation. Results showed that there was a significantly positive relation (r>0.90) between Cd release concentration/amount/ratio and exogenous salt (NaCl). Besides, the more exogenous salt (NaCl) was added; maximum release concentration/amount of Cd appeared the earlier. It was found that exogenous salt (NaCl) addition could obviously promote Cd release from acidified Cd contaminated brown soil. It was believed that this could be mainly due to the cation exchange between Cd2+ and Na+, together with the dissociation and/or complexation between Cl- and Cd2+. In addition, available adsorption sites reduction by exchange base in soil causing Cd changed from solid state to soil solution was also a probable reason.

Effects of land use and land cover changes on water quality in the uMngeni river catchment, South Africa

Science.gov (United States)

Namugize, Jean Nepomuscene; Jewitt, Graham; Graham, Mark

2018-06-01

Land use and land cover change are major drivers of water quality deterioration in watercourses and impoundments. However, understanding of the spatial and temporal variability of land use change characteristics and their link to water quality parameters in catchments is limited. As a contribution to address this limitation, the objective of this study is to assess the linkages between biophysico-chemical water quality parameters and land use and land cover (LULC) classes in the upper reaches of the uMngeni Catchment, a rapidly developing catchment in South Africa. These were assessed using Geographic Information Systems tools and statistical analyses for the years 1994, 2000, 2008 and 2011 based on changes over time of eight LULC classes and available water quality information. Natural vegetation, forest plantations and cultivated areas occupy 85% of the catchment. Cultivated, urban/built-up and degraded areas increased by 6%, 4.5% and 3%, respectively coinciding with a decrease in natural vegetation by 17%. Variability in the concentration of water quality parameters from 1994 to 2011 and an overall decline in water quality were observed. Escherichia coli (E. coli) levels exceeding the recommended guidelines for recreation and public health protection was noted as a major issue at seven of the nine sampling points. Overall, water supply reservoirs in the catchment retained over 20% of nutrients and over 85% of E. coli entering them. A relationship between land use types and water quality variables was found. However, the degree and magnitude of the associations varies between sub-catchments and is difficult to quantify. This highlights the complexity and the site-specific nature of relationships between land use types and water quality parameters in the catchment. Thus, this study provides useful findings on the general relationship between land use and land cover and water quality degradation, but highlights the risks of applying simple relationships or adding

Impact of catchment geophysical characteristics and climate on the regional variability of dissolved organic carbon (DOC) in surface water.

Science.gov (United States)

Cool, Geneviève; Lebel, Alexandre; Sadiq, Rehan; Rodriguez, Manuel J

2014-08-15

Dissolved organic carbon (DOC) is a recognized indicator of natural organic matter (NOM) in surface waters. The aim of this paper is twofold: to evaluate the impact of geophysical characteristics, climate and ecological zones on DOC concentrations in surface waters and, to develop a statistical model to estimate the regional variability of these concentrations. In this study, multilevel statistical analysis was used to achieve three specific objectives: (1) evaluate the influence of climate and geophysical characteristics on DOC concentrations in surface waters; (2) compare the influence of geophysical characteristics and ecological zones on DOC concentrations in surface waters; and (3) develop a model to estimate the most accurate DOC concentrations in surface waters. The case study involved 115 catchments from surface waters in the Province of Quebec, Canada. Results showed that mean temperatures recorded 60 days prior to sampling, total precipitation 10 days prior to sampling and percentages of wetlands, coniferous forests and mixed forests have a significant positive influence on DOC concentrations in surface waters. The catchment mean slope had a significant negative influence on DOC concentrations in surface waters. Water type (lake or river) and deciduous forest variables were not significant. The ecological zones had a significant influence on DOC concentrations. However, geophysical characteristics (wetlands, forests and slope) estimated DOC concentrations more accurately. A model describing the variability of DOC concentrations was developed and can be used, in future research, for estimating DBPs in drinking water as well evaluating the impact of climate change on the quality of surface waters and drinking water. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of landscape heterogeneity on water available to tropical forests in an Amazonian catchment and implications for modeling drought response: Water Available to Tropical Forest

Energy Technology Data Exchange (ETDEWEB)

Fang, Yilin; Leung, Lai-Yung; Duan, Zhuoran; Wigmosta, Mark S.; Maxwell, Reed M.; Chambers, Jeffrey Q.; Tomasella, Javier

2017-08-18

The Amazon basin experienced periodic droughts in the past, and climate models projected more intense and frequent droughts in the future. How tropical forests respond to drought may depend on water availability, which is modulated by landscape heterogeneity. Using the one-dimensional ACME Land Model (ALM) and the three-dimensional ParFlow variably saturated flow model, a series of numerical experiments were performed for the Asu catchment in central Amazon to elucidate processes that influence water available for plant use and provide insights for improving Earth system models. Results from ParFlow show that topography has a dominant influence on groundwater table and runoff through lateral flow. Without any representations of lateral processes, ALM simulates very different seasonal variations in groundwater table and runoff compared to ParFlow even if it is able to reproduce the long-term spatial average groundwater table of ParFlow through simple parameter calibration. In the ParFlow simulations, the groundwater table is evidently deeper and the soil saturation is lower in the plateau compared to the valley. However, even in the plateau during the dry season in the drought year of 2005, plant transpiration is not water stressed in the ParFlow simulations as the soil saturation is still sufficient to maintain a soil matric potential for the stomata to be fully open. This finding is insensitive to uncertainty in atmospheric forcing and soil parameters, but the empirical wilting formulation used in the models is an important factor that should be addressed using observations and modeling of coupled plant hydraulics-soil hydrology processes in future studies.

Flash flood modelling for ungauged catchments

Science.gov (United States)

Garambois, P.-A.; Roux, H.; Larnier, K.; Dartus, D.

2012-04-01

Flash flood is a very intense and quick hydrologic response of a catchment to rainfall. This phenomenon has a high spatial-temporal variability as its generating storm, often hitting small catchments (few km2). Data collected by (Gaume et al. 2009) about 500 flash floods over the last 50 years showed that they could occur everywhere in Europe and more often in the Mediterranean regions, Alpine regions and continental Europe. Given the small spatial-temporal scales and high variability of flash floods, their prediction remains a hard exercise as the necessary data are often scarce. Flash flood prediction on ungauged catchments is one of the challenges of hydrological modelling as defined by (Sivapalan et al. 2003). Several studies have been headed up with the MARINE model (Modélisation de l'Anticipation du Ruissellement et des Inondations pour des évèNements Extrêmes) for the Gard region (France), (Roux et al. 2011), (Castaings et al. 2009). This physically based spatially distributed rainfall runoff model is dedicated to flash flood prediction. The study aims at finding a methodology for flash flood prediction at ungauged locations in the Cévennes-Vivarais region in particular. The regionalization method is based on multiple calibrations on gauged catchments in order to extract model structures (model + parameter values) for each catchment. Several mathematical methods (multiple regressions, transfer functions, krigging…) will then be tested to calculate a regional parameter set. The study also investigates the usability of additional hydrologic indices at different time scales to constrain model predictions from parameters obtained using these indices, and this independently of the model considered. These hydrologic indices gather information on hydrograph shape or catchment dynamic for instance. Results explaining global catchments behaviour are expected that way. The spatial-temporal variability of storms is also described through indices and linked with

Evaluation of hydrologic equilibrium in a mountainous watershed: incorporating forest canopy spatial adjustment to soil biogeochemical processes

Science.gov (United States)

Mackay, D. Scott

Hydrologic equilibrium theory has been used to describe both short-term regulation of gas exchange and long-term adjustment of forest canopy density. However, by focusing on water and atmospheric conditions alone a hydrologic equilibrium may impose an oversimplification of the growth of forests adjusted to hydrology. In this study nitrogen is incorporated as a third regulation of catchment level forest dynamics and gas exchange. This was examined with an integrated distributed hydrology and forest growth model in a central Sierra Nevada watershed covered primarily by old-growth coniferous forest. Water and atmospheric conditions reasonably reproduced daily latent heat flux, and predicted the expected catenary trend of leaf area index (LAI). However, it was not until the model was provided a spatially detailed description of initial soil carbon and nitrogen pools that spatial patterns of LAI were generated. This latter problem was attributed to a lack of soil history or memory in the initialization of the simulations. Finally, by reducing stomatal sensitivity to vapor pressure deficit (VPD) the canopy density increased when water and nitrogen limitations were not present. The results support a three-control hydrologic equilibrium in the Sierra Nevada watershed. This has implications for modeling catchment level soil-vegetation-atmospheric interactions over interannual, decade, and century time-scales.

Conifer density within lake catchments predicts fish mercury concentrations in remote subalpine lakes

Science.gov (United States)

Eagles-Smith, Collin A.; Herring, Garth; Johnson, Branden L.; Graw, Rick

2016-01-01

Remote high-elevation lakes represent unique environments for evaluating the bioaccumulation of atmospherically deposited mercury through freshwater food webs, as well as for evaluating the relative importance of mercury loading versus landscape influences on mercury bioaccumulation. The increase in mercury deposition to these systems over the past century, coupled with their limited exposure to direct anthropogenic disturbance make them useful indicators for estimating how changes in mercury emissions may propagate to changes in Hg bioaccumulation and ecological risk. We evaluated mercury concentrations in resident fish from 28 high-elevation, sub-alpine lakes in the Pacific Northwest region of the United States. Fish total mercury (THg) concentrations ranged from 4 to 438 ng/g wet weight, with a geometric mean concentration (±standard error) of 43 ± 2 ng/g ww. Fish THg concentrations were negatively correlated with relative condition factor, indicating that faster growing fish that are in better condition have lower THg concentrations. Across the 28 study lakes, mean THg concentrations of resident salmonid fishes varied as much as 18-fold among lakes. We used a hierarchal statistical approach to evaluate the relative importance of physiological, limnological, and catchment drivers of fish Hg concentrations. Our top statistical model explained 87% of the variability in fish THg concentrations among lakes with four key landscape and limnological variables: catchment conifer density (basal area of conifers within a lake's catchment), lake surface area, aqueous dissolved sulfate, and dissolved organic carbon. Conifer density within a lake's catchment was the most important variable explaining fish THg concentrations across lakes, with THg concentrations differing by more than 400 percent across the forest density spectrum. These results illustrate the importance of landscape characteristics in controlling mercury bioaccumulation in fish.

Hydrological response to bauxite mining and rehabilitation in the jarrah forest in south west Australia

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Andrew H. Grigg

2017-08-01

New hydrological insights for the region: Mining caused a peak streamflow response of 225 mm or 18% of rainfall, before returning to pre-disturbance levels 11 years after mining commenced. Streamflow changes were closely associated with changes in a groundwater discharge area in the valley floor. Changes in groundwater level, in turn, were related to rainfall and leaf area index, and these effects did not differ between mine rehabilitation and unmined catchment areas. The streamflow response to mining could not be distinguished from the intensive thinning treatment in this study, or from clearfelling or clearing for agriculture reported elsewhere in the jarrah forest. The results indicate that shallow subsurface flow processes, considered to dominate streamflow generation in jarrah forest catchments, do not extend beyond the valley floor and immediately adjacent slopes which were not disturbed by mining.

Simulating stream response to floodplain connectivity, reforestation and wetland restoration from reach to catchment scales

Science.gov (United States)

Singh, N.; Bomblies, A.; Wemple, B. C.; Ricketts, T.

2017-12-01

Natural infrastructure (e.g., floodplains, forests) can offer multiple ecosystem services (ES), including flood resilience and water quality improvement. In order to maintain these ES, state, federal and non-profit organizations may consider various interventions, such as increased floodplain connectivity, reforestation, and wetland restoration to minimize flood peaks and erosion during events. However, the effect of these interventions on hydro-geomorphic responses of streams from reach to catchment scales (>100 km2) are rarely quantified. We used stream geomorphic assessment datasets with a hydraulic model to investigate the influence of above mentioned interventions on stream power (SP), water depth (WD) and channel velocity (VEL) during floods of 2yr and 100yr return periods for three catchments in the Lake Champlain basin, Vermont. To simulate the effect of forests and wetlands, we changed the Manning's coefficient in the model, and to simulate the increased connectivity of the floodplain, we edited the LIDAR data to lower bank elevations. We find that the wetland scenario resulted in the greatest decline in WD and SP, whereas forested scenario exhibited maximum reduction in VEL. The connectivity scenario showed a decline in almost all stream responses, but the magnitude of change was relatively smaller. On average, 35% (2yr) and 50% (100yr) of altered reaches demonstrated improvement over baseline, and 39% (2yr) and 31% (100yr) of altered reaches showed degradation over baseline, across all interventions. We also noted changes in stream response along unaltered reaches (>30%), where we did not make interventions. Overall, these results point to the complexity related to stream interventions and suggest careful evaluation of spatially explicit tradeoffs of these interventions on river-floodplain ecosystem. The proposed approach of simulating and understanding stream's response to interventions, prior to the implementation of restoration activities, may lead to

Changing forest water yields in response to climate warming: results from long-term experimental watershed sites across North America

Science.gov (United States)

Irena F. Creed; Adam T. Spargo; Julia A. Jones; Jim M. Buttle; Mary B. Adams; Fred D. Beall; Eric G. Booth; John L. Campbell; Dave Clow; Kelly Elder; Mark B. Green; Nancy B. Grimm; Chelcy Miniat; Patricia Ramlal; Amartya Saha; Stephen Sebestyen; Dave Spittlehouse; Shannon Sterling; Mark W. Williams; Rita Winkler; Huaxia. Yao

2014-01-01

Climate warming is projected to affect forest water yields but the effects are expected to vary.We investigated how forest type and age affect water yield resilience to climate warming. To answer this question, we examined the variability in historical water yields at long-term experimental catchments across Canada and the United States over 5-year cool and warm...

INTEGRATED SUSTAINABLE MANGROVE FOREST MANAGEMENT

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Cecep Kusmana

2015-07-01

Full Text Available Mangrove forest as a renewable resource must be managed based on sustainable basis in which the benefits of ecological, economic and social from the forest have to equity concern in achieving the optimum forest products and services in fulfill the needs of recent generation without destruction of future generation needs and that does not undesirable effects on the physical and social environment. This Sustainable Forest Management (SFM practices needs the supporting of sustainability in the development of social, economic and environment (ecological sounds simultaneously, it should be run by the proper institutional and regulations. In operational scale, SFM need integration in terms of knowledge, technical, consultative of stakeholders, coordination among sectors and other stakeholders, and considerations of ecological inter-relationship in which mangroves as an integral part of both a coastal ecosystem and a watershed (catchment area. Some tools have been developed to measure the performent of SFM, such as initiated by ITTO at 1992 and followed by Ministry of Forestry of Indonesia (1993, CIFOR (1995, LEI (1999, FSC (1999, etc., however, the true nuance of SFM’s performance is not easy to be measured. 

Framework for measuring sustainable development in catchment systems.

Science.gov (United States)

Walmsley, Jay J

2002-02-01

Integrated catchment management represents an approach to managing the resources of a catchment by integrating environmental, economic, and social issues. It is aimed at deriving sustainable benefits for future generations, while protecting natural resources, particularly water, and minimizing possible adverse social, economic, and environmental consequences. Indicators of sustainable development, which summarize information for use in decision-making, are invaluable when trying to assess the diverse, interacting components of catchment processes and resource management actions. The Driving-Forces--Pressure--State--Impact--Response (DPSIR) indicator framework is useful for identifying and developing indicators of sustainable development for catchment management. Driving forces have been identified as the natural conditions occurring in a catchment and the level of development and economic activity. Pressures include the natural and anthropogenic supply of water, water demand, and water pollution. State indicators can be split into those of quantity and those of quality. Impacts include those that affect the ecosystems directly and those that impact the use value of the resource. It core indicators are identified within each of the categories given in the framework, most major catchment-based management issues can be evaluated. This framework is applied to identify key issues in catchment management in South Africa, and develop a set of indicators for evaluating catchments throughout the country.

Typecasting catchments: Classification, directionality, and the pursuit of universality

Science.gov (United States)

Smith, Tyler; Marshall, Lucy; McGlynn, Brian

2018-02-01

Catchment classification poses a significant challenge to hydrology and hydrologic modeling, restricting widespread transfer of knowledge from well-studied sites. The identification of important physical, climatological, or hydrologic attributes (to varying degrees depending on application/data availability) has traditionally been the focus for catchment classification. Classification approaches are regularly assessed with regard to their ability to provide suitable hydrologic predictions - commonly by transferring fitted hydrologic parameters at a data-rich catchment to a data-poor catchment deemed similar by the classification. While such approaches to hydrology's grand challenges are intuitive, they often ignore the most uncertain aspect of the process - the model itself. We explore catchment classification and parameter transferability and the concept of universal donor/acceptor catchments. We identify the implications of the assumption that the transfer of parameters between "similar" catchments is reciprocal (i.e., non-directional). These concepts are considered through three case studies situated across multiple gradients that include model complexity, process description, and site characteristics. Case study results highlight that some catchments are more successfully used as donor catchments and others are better suited as acceptor catchments. These results were observed for both black-box and process consistent hydrologic models, as well as for differing levels of catchment similarity. Therefore, we suggest that similarity does not adequately satisfy the underlying assumptions being made in parameter regionalization approaches regardless of model appropriateness. Furthermore, we suggest that the directionality of parameter transfer is an important factor in determining the success of parameter regionalization approaches.

Hydrologic comparison between a lowland catchment (Kielstau, Germany and a mountainous catchment (XitaoXi, China using KIDS model in PCRaster

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N. Fohrer

2009-08-01

Full Text Available The KIDS model (Kielstau Discharge Simulation model is a simple rainfall-runoff model developed originally for the Kielstau catchment. To extend its range of application we applied it to a completely different catchment, the XitaoXi catchment in China. Kielstau is a small (51 km² lowland basin in Northern Germany, with large proportion of wetland area. And XitaoXi is a mesoscale (2271 km² mountainous basin in the south of China. Both catchments differ greatly in size, topography, landuse, soil properties, and weather conditions. We compared two catchments in these features and stress on the analysis how the specific catchment characteristics could guide the adaptation of KIDS model and the parameter estimation for streamflow simulation. The Nash and Sutcliffe coefficient was 0.73 for Kielstau and 0.65 for XitaoXi. The results suggest that the application of KIDS model may require adjustments according to the specific physical background of the study basin.

Modelling impacts of temperature, and acidifying and eutrophying deposition on DOC trends

Science.gov (United States)

Sawicka, Kasia; Rowe, Ed; Evans, Chris; Monteith, Don; Vanguelova, Elena; Wade, Andrew; Clark, Joanna

2017-04-01

Surface water dissolved organic carbon (DOC) concentrations in large parts of the northern hemisphere have risen over the past three decades, raising concern about enhanced contributions of carbon to the atmosphere and seas and oceans. The effect of declining acid deposition has been identified as a key control on DOC trends in soil and surface waters, since pH and ionic strength affect sorption and desorption of DOC. However, since DOC is derived mainly from recently-fixed carbon, and organic matter decomposition rates are considered sensitive to temperature, uncertainty persists regarding the extent to the relative importance of different drivers that affect these upward trends. We ran the dynamic model MADOC (Model of Acidity and Soil Organic Carbon) for a range of UK soils (podzols, gleysols and peatland), for which the time-series were available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20 years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to elevate the DOC recovery trajectory significantly. The second most influential cause of rising DOC in the model simulations was N deposition in ecosystems that are N-limited and respond with stimulated plant growth. Although non-marine chloride deposition made some contribution to acidification and recovery, it was not amongst the main drivers of DOC change. Warming had almost no effect on modelled historic DOC trends, but may prove to be a significant driver of DOC in future via its influence

Relationship of a Special Acidified Milk Protein Drink with Cognitive Performance: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Young Adults

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Yoshie Saito

2018-05-01

Full Text Available A previous in vivo study with rats suggested that a special milk protein drink manufactured using an acidification procedure to suppress the aggregation of milk proteins was absorbed quickly after feeding. We performed a randomized, double-blind, placebo-controlled, repeated-measure crossover study to investigate the short-term effects on cognitive performance in 29 healthy young adult men after they consumed this drink in the morning. After an overnight fast, subjects were tested for performance in the Uchida–Kraepelin serial arithmetic test and the Stroop test as well as for subjective feeling, body temperature, and heart rate variability before and after consumption of either the acidified milk protein drink or an isoenergetic placebo drink. Subjects showed a significant improvement in performance in the Uchida–Kraepelin test, the primary outcome measured, when they consumed the acidified milk protein drink compared with the placebo control condition. In addition, consumption of the acidified milk protein drink, compared with the placebo control, was associated with increases in vagally-mediated heart rate variability indices which, from recent theoretical perspectives, may reflect a higher ability to modulate cognitive and behavioral processes. There was no significant difference in subjective feelings and body temperature between the test drink conditions. These data suggest that consumption of the acidified milk protein drink may improve cognitive performance, with possible involvement of physiological systems that regulate cognition and behavior.

Extraction of steviol glycosides from fresh Stevia using acidified water; clarification followed by ultrafiltration and nanofiltration

NARCIS (Netherlands)

Kootstra, A.M.J.; Elissen, H.J.H.; Huurman, Sander

2016-01-01

As part of the PPS Kleinschalige bioraffinage project (WP1b), fresh Stevia material was used in the extraction of steviol glycosides using water acidified through conversion of sugar by microorganisms naturally present on the plant. Two successive harvests from the same plot were used. Previous

One Year of Monthly N and O Isotope Measurements in Nitrate from 18 Streamwater Monitoring Stations Within the Predominantly Pastoral Upper Manawatu Catchment, New Zealand

Science.gov (United States)

Baisden, W. T.; Douence, C.

2010-12-01

New Zealand's intensive pastoral agricultural systems have a significant impact on water quality due to nitrogen loading in rivers. A research programme has been designed to develop indicators of the sources and denitrification losses of nitrate in streamwater. This work describes the results of one year of monthly measurements at ~18 monitoring locations in the 1260 square km upper Manawatu River catchment. The catchment was chosen for study because it is among the most pastoral catchments in New Zealand, with little non-pastoral agriculture and limited forest area outside of the Tararua mountain range on the west side of the catchment. The use of N and O isotope ratios in nitrate has considerable potential to elucidate the sources and fate of nitrate with greater precision than in most other nations due to the lack of nitrate in atmospheric deposition and the lack of nitrates used as fertilizer. We measured N and O isotope ratios in nitrate plus nitrite using cadmium and azide chemical denitrification method, and refer to the results as nitrate for brevity due to low nitrite concentrations. When examined as annual averages at each monitoring site, we found the lowest N and O isotope ratios in our only site draining native forest. All agricultural monitoring sites sit approximately on a 1:1 line, enriched in N-15 and O-18 by 2-6 per mil relative to the native forest subcatchment. The three main effluent point sources in the catchment demonstrated unexpected variability in isotope ratios. Two modern sewage treatment ponds had N and O isotope ratios close to those found in agricultural catchments, while a closed meat freezing factory effluent pond had isotope ratios strongly enriched in N-15 and O-18. The lack of summer low flows during monitoring period, combined with the variability in isotope ratios from point source, appeared to be responsible for our inability to clearly detect the effect of point sources in the isotope data from stations upstream and

Characterising groundwater-dominated lowland catchments: the UK Lowland Catchment Research Programme (LOCAR

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2007-01-01

Full Text Available This paper reports on a major UK initiative to address deficiencies in understanding the hydro-ecological response of groundwater-dominated lowland catchments. The scope and objectives of this national programme are introduced and focus on one of three sets of research basins – the Pang/Lambourn Chalk catchments, tributaries of the river Thames in southern England. The motivation for the research is the need to support integrated management of river systems that have high ecological value and are subject to pressures that include groundwater abstraction for water supply, diffuse pollution, and land use and climate change. An overview of the research programme is provided together with highlights of some current research findings concerning the hydrological functioning of these catchments. Despite the importance of the Chalk as a major UK aquifer, knowledge of the subsurface movement of water and solutes is poor. Solute transport in the dual porosity unsaturated zone depends on fracture/matrix interactions that are difficult to observe; current experimental and modelling research supports the predominance of matrix flow and suggests that slow migration of a time-history of decades of nutrient loading is occurring. Groundwater flows are complex; catchments vary seasonally and are ill-defined and karst features are locally important. Groundwater flow pathways are being investigated using natural and artificial geochemical tracers based on experimental borehole arrays; stream-aquifer interaction research is using a combination of geophysics, borehole array geochemistry and longitudinal profiles of stream flow and solutes. A complex picture of localised subsurface inflows, linked to geological controls and karst features, and significant longitudinal groundwater flow below the river channel is emerging. Management implications are discussed. Strategies to control surface application of nutrients are expected to have little effect on groundwater

Nested Tracer Studies In Catchment Hydrology: Towards A Multiscale Understanding of Runoff Generation and Catchment Funtioning

Science.gov (United States)

Soulsby, C.; Rodgers, P.; Malcolm, I. A.; Dunn, S.

Geochemical and isotopic tracers have been shown to have widespread utility in catch- ment hydrology in terms of identifying hydrological source areas and characterising residence time distributions. In many cases application of tracer techniques has pro- vided insights into catchment functioning that could not be obtained from hydromet- ric and/or modelling studies alone. This paper will show how the use of tracers has contributed to an evolving perceptual model of hydrological pathways and runoff gen- eration processes in catchments in the Scottish highlands. In particular the paper will focus on the different insights that are gained at three different scales of analysis; (a) nested sub-catchments within a mesoscale (ca. 200 square kilometers) experimen- tal catchment; (b) hillslope-riparian interactions and (c) stream bed fluxes. Nested hydrometric and hydrochemical monitoring within the mesoscale Feugh catchment identified three main hydrological response units: (i) plateau peatlands which gener- ated saturation overland flow in the catchment headwaters, (ii) steep valley hillslopes which drain from the plateaux into (iii) alluvial and drift aquifers in the valley bottoms. End Member Mixing Analysis (EMMA) in 8 nested sub-catchments indicated that that stream water tracer concentrations can be modelled in terms of 2 dominant runoff pro- cesses; overland flow from the peat and groundwater from the drift aquifers. Ground- water contributions generally increased with catchment size, though this was moder- ated by the characteristics of individual sub-basins, with drift cover being particularly important. Hillslope riparian interactions were also examined using tracers, hydromet- ric data and a semi-distributed hydrological model. This revealed that in the glaciated, drift covered terrain of the Scottish highlands, extensive valley bottom aquifers effec- tively de-couple hillslope waters from the river channel. Thus, riparian groundwater appears to significantly

Compensatory vapor loss and biogeochemical attenuation along flowpaths mute the water resources impacts of insect-induced forest mortality

Science.gov (United States)

Biederman, J. A.; Brooks, P. D.; Harpold, A. A.; Gochis, D. J.; Ewers, B. E.; Reed, D. E.; Gutmann, E. D.

2013-12-01

Forested montane catchments are critical to the amount and quality of downstream water resources. In western North America more than 60 million people rely on mountain precipitation, and water managers face uncertain response to an unprecedented forest die-off from mountain pine beetle (MPB) infestation. Reduced snow interception and transpiration are expected to increase streamflow, while increased organic matter decay is expected to increase biogeochemical stream fluxes. Tree- to plot-scale observations have documented some of the expected changes, but there has been little significant change to streamflow or water quality at the larger scales relevant to water resources. A critical gap exists in our understanding of why tree-scale process changes have not led to the expected, large-scale increases in streamflow and biogeochemical fluxes. We address this knowledge gap with observations of water and biogeochemical fluxes at nested spatial scales including tree, hillslope, and catchments from 3 to 700 ha with more than 75% mortality. Catchment discharge showed reduced water yield consistent with co-located eddy covariance observations showing increased vapor losses following MPB. Stable water isotopes showed progressive kinetic fractionation (i.e. unsaturated transition layer above the evaporating surface) in snowpack, soil water and streams indicating greater abiotic evaporation from multiple water sources offsetting decreased interception and transpiration. In the 3rd to 5th years following MPB forest mortality, soil water DOC and DON were similar beneath killed and healthy trees, but concentrations were elevated 2-10 times in groundwater of MPB-impacted sites as compared to unimpacted. Stream water DOC and DON were about 3 times as large during snowmelt runoff in ephemeral zero-order channels of MPB-impacted sites compared to unimpacted. Processing in the headwater streams of MPB-impacted forests rapidly attenuated dissolved organic matter. From the MPB

Bioavailability of riverine dissolved organic matter in three Baltic Sea estuaries and the effect of catchment land use

DEFF Research Database (Denmark)

Asmala, E.; Autio, R.; Kaartokallio, H.

2013-01-01

The microbial degradation of dissolved organic carbon and nitrogen (DOC, DON) was studied in three Finnish boreal estuaries with contrasting land use patterns (Kiiminkijoki - natural forest and peatland; Kyrönjoki - agricultural; Karjaanjoki - mixed/urban). Bioassays of 12-18 d long durations were...... the estuaries, from 7.9 to 10.6% and from 5.5 to 21.9%, respectively. DOM originating from the catchment dominated by natural forests and peatlands (Kiiminkijoki) had the lowest DOC and DON degradation rates, as well as the lowest proportions of biodegradable DOC and DON. A greater proportion of agricultural...... in the Kyrönjoki estuary. Lower DOC:DON ratios, smaller molecular weight and higher CDOM absorption spectral slope values of DOM resulted in higher proportion of the initial DOC and DON being transferred to microbial growth and therefore to the pelagic food web. The pristine, peatland and forest...

Tree species traits cause divergence in soil acidification during four decades of postagricultural forest development

DEFF Research Database (Denmark)

Schrijver, An de; Frenne, Pieter de; Staelens, Jeroen

2012-01-01

-depth understanding of tree species-specific effects on soil acidification is therefore crucial, particularly in view of the predicted global increases in acidifying nitrogen (N) deposition. Here, we report soil acidification rates in a chronosequence of broadleaved deciduous forests planted on former arable land...... and unequivocally drives postagricultural forests towards more acidic conditions, but the rate of soil acidification is also determined by the tree species-specific leaf litter quality and litter decomposition rates. We propose that the intrinsic differences in leaf litter quality among tree species create...... fundamentally different nutrient cycles within the ecosystem, both directly through the chemical composition of the litter and indirectly through its effects on the size and composition of earthworm communities. Poor leaf litter quality contributes to the absence of a burrowing earthworm community, which...

Assessment of surface water resources availability using catchment modelling and the results of tracer studies in the mesoscale Migina Catchment, Rwanda

Science.gov (United States)

Munyaneza, O.; Mukubwa, A.; Maskey, S.; Uhlenbrook, S.; Wenninger, J.

2014-12-01

In the present study, we developed a catchment hydrological model which can be used to inform water resources planning and decision making for better management of the Migina Catchment (257.4 km2). The semi-distributed hydrological model HEC-HMS (Hydrologic Engineering Center - the Hydrologic Modelling System) (version 3.5) was used with its soil moisture accounting, unit hydrograph, liner reservoir (for baseflow) and Muskingum-Cunge (river routing) methods. We used rainfall data from 12 stations and streamflow data from 5 stations, which were collected as part of this study over a period of 2 years (May 2009 and June 2011). The catchment was divided into five sub-catchments. The model parameters were calibrated separately for each sub-catchment using the observed streamflow data. Calibration results obtained were found acceptable at four stations with a Nash-Sutcliffe model efficiency index (NS) of 0.65 on daily runoff at the catchment outlet. Due to the lack of sufficient and reliable data for longer periods, a model validation was not undertaken. However, we used results from tracer-based hydrograph separation from a previous study to compare our model results in terms of the runoff components. The model performed reasonably well in simulating the total flow volume, peak flow and timing as well as the portion of direct runoff and baseflow. We observed considerable disparities in the parameters (e.g. groundwater storage) and runoff components across the five sub-catchments, which provided insights into the different hydrological processes on a sub-catchment scale. We conclude that such disparities justify the need to consider catchment subdivisions if such parameters and components of the water cycle are to form the base for decision making in water resources planning in the catchment.

Catchment scale multi-objective flood management

Science.gov (United States)

Rose, Steve; Worrall, Peter; Rosolova, Zdenka; Hammond, Gene

2010-05-01

Rural land management is known to affect both the generation and propagation of flooding at the local scale, but there is still a general lack of good evidence that this impact is still significant at the larger catchment scale given the complexity of physical interactions and climatic variability taking place at this level. The National Trust, in partnership with the Environment Agency, are managing an innovative project on the Holnicote Estate in south west England to demonstrate the benefits of using good rural land management practices to reduce flood risk at the both the catchment and sub-catchment scales. The Holnicote Estate is owned by the National Trust and comprises about 5,000 hectares of land, from the uplands of Exmoor to the sea, incorporating most of the catchments of the river Horner and Aller Water. There are nearly 100 houses across three villages that are at risk from flooding which could potentially benefit from changes in land management practices in the surrounding catchment providing a more sustainable flood attenuation function. In addition to the contribution being made to flood risk management there are a range of other ecosystems services that will be enhanced through these targeted land management changes. Alterations in land management will create new opportunities for wildlife and habitats and help to improve the local surface water quality. Such improvements will not only create additional wildlife resources locally but also serve the landscape response to climate change effects by creating and enhancing wildlife networks within the region. Land management changes will also restore and sustain landscape heritage resources and provide opportunities for amenity, recreation and tourism. The project delivery team is working with the National Trust from source to sea across the entire Holnicote Estate, to identify and subsequently implement suitable land management techniques to manage local flood risk within the catchments. These

The Analysis of Land Use Based on CORINE Land Cover in the Romanian Part of the Tisa Catchment Area

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CIPRIAN MOLDOVAN

2010-01-01

Full Text Available The analysis of the land use structure of the 13 counties of the Romanian part of Tisa catchment area has been made according to the 2000 edition of CORINE Land Cover, while the 1990 edition has been used for comparative purposes. Out of the total area of 8,269,229.48 hectares, the forests cover 37.92%, the arable lands 35.02% and the grasslands 17.97%. The other types of land use have lower weights, such as the continuous and discontinuous urban fabric 4.81%, the orchards 1.10% and the vineyards 0.98%. In the category of forests, the following types of land use are included: broad-leaved forests, which form the majority (24.72%, coniferous forests (6.22%, mixed forests (3.46% and transitional woodland-shrub areas (3.52%. The forests are mainly located in the Carpathians and the hills. The non-irrigated arable lands (23.50% are predominant within the arable lands. They lie mostly in the Western Plain and in the basins and corridors of the Transylvanian Depression and the Western Hills. The analysis of the dynamics of the land use structure between 1990 and 2000 indicates a relative stability in the case of forests, a decrease of arable lands and an increase of grasslands.

Forests and water - Friends or foes?. Hydrological implications of deforestation and land degradation in semi-arid Tanzania

International Nuclear Information System (INIS)

Sandstroem, K.

1995-01-01

In the study area in Babati District in Tanzania a multi-component research approach was attempted. Two catchments, one forested and one deforested-degraded, were studied regarding soil properties, runoff and groundwater recharge. This was done both in the field and with the use of two computer models: one simulating groundwater recharge as a function of rainfall variability, and one simulating hydrological implications of massive land cover conversion on the flooding of nearby Lake Babati. Three major findings came out of the study. The first is that most forested catchments (in various hydroclimates and landscapes) will increase the runoff following deforestation (due to less evapotranspiration). This is well-established knowledge, but it also depends on the actual conditions at hand. These conditions are defined as hydroclimate, soil texture and slope. In humid-temperate climates with coarse soils on flat land, the conditions strongly favor increased runoff following deforestation. However, in dry regions with fine textured soils on hilly ground, and where deforestation also implies land degradation, less dry season flow is likely to develop after a considerable adjustment period has been allowed. Secondly, the prevalence of preferential flow in a forest soil, as compared to a compacted and eroded soil, must be a key component in an explanation of why more dry season flow can emerge from a forested as compared to a deforested catchment in the dry tropics. Thirdly, there are several aspects of semi-arid and arid tropical hydrology which make comparisons with humid-temperate regions difficult and require special attention in the management of water resources in the dry tropics. 14 refs, 18 figs, 1 tab

Large catchment area recharges Titan's Ontario Lacus

Science.gov (United States)

Dhingra, Rajani D.; Barnes, Jason W.; Yanites, Brian J.; Kirk, Randolph L.

2018-01-01

We seek to address the question of what processes are at work to fill Ontario Lacus while other, deeper south polar basins remain empty. Our hydrological analysis indicates that Ontario Lacus has a catchment area spanning 5.5% of Titan's surface and a large catchment area to lake surface area ratio. This large catchment area translates into large volumes of liquid making their way to Ontario Lacus after rainfall. The areal extent of the catchment extends to at least southern mid-latitudes (40°S). Mass conservation calculations indicate that runoff alone might completely fill Ontario Lacus within less than half a Titan year (1 Titan year = 29.5 Earth years) assuming no infiltration. Cassini Visual and Infrared Mapping Spectrometer (VIMS) observations of clouds over the southern mid and high-latitudes are consistent with precipitation feeding Ontario's large catchment area. This far-flung rain may be keeping Ontario Lacus filled, making it a liquid hydrocarbon oasis in the relatively dry south polar region.

Transport and Breakdown of Organic Matter in Urban and Forested Streams: The Effects of Altered Hydrology and Landscape Position

Science.gov (United States)

Belt, K. T.; Swan, C. M.; Pouyat, R. V.; Kaushal, S.; Groffman, P. M.; Stack, W. P.; Fisher, G. T.

2006-05-01

A better understanding of how urbanization and trees interact to alter organic matter transport and cycling is needed to assess retention in catchments and streams, as well as to estimate the magnitude of carbon fluxes to the atmosphere and to downstream aquatic ecosystems. The influx of particulate and dissolved organic matter (POM/DOC) to headwater streams normally originates within or near riparian areas, and is important to aquatic food webs in stream ecosystems. Urban catchments, however, have huge effective drainage densities (due to storm drainage infrastructure), which facilitate a POM/DOC "gutter subsidy" to streams that dwarfs riparian inputs and alters benthic litter quality (and represents a major short-circuit in the carbon vegetation-soil cycle.) We measured in-situ leaf litter breakdown rates, flows, DOC, BOD and nutrients in forested, suburban and urban streams of the BES LTER and Baltimore City DPW sampling networks, which encompassed a variety of urban and rural landscapes. Sycamore and Planetree leaf litter in-situ experiments revealed faster breakdown rates for suburban and urban landscape litter than for riparian litter, with rates being much faster than literature values for forested catchments. DOC, BOD and nutrient data (storm and dry weather) from BES/DPW stream sites showed much higher concentrations and loads in the more urbanized catchments and indicate the streams are likely heterotrophic and experience transient but high dissolved oxygen demands. High nutrient concentrations, faster litter breakdown rates, and substantially higher upland urban fluxes of organic matter (particulate and dissolved) in urban streams suggest that export rates are likely substantially higher than in forested systems and that carbon loads to both downstream aquatic systems and to the atmosphere (as CO2) are substantial.

Evaluation of sediment and 137Cs redistribution in the Oginosawa River catchment near the Fukushima Dai-ichi Nuclear Power Plant using integrated watershed modeling.

Science.gov (United States)

Sakuma, Kazuyuki; Malins, Alex; Funaki, Hironori; Kurikami, Hiroshi; Niizato, Tadafumi; Nakanishi, Takahiro; Mori, Koji; Tada, Kazuhiro; Kobayashi, Takamaru; Kitamura, Akihiro; Hosomi, Masaaki

2018-02-01

The Oginosawa River catchment lies 15 km south-west of the Fukushima Dai-ichi nuclear plant and covers 7.7 km 2 . Parts of the catchment were decontaminated between fall 2012 and March 2014 in preparation for the return of the evacuated population. The General-purpose Terrestrial Fluid-flow Simulator (GETFLOWS) code was used to study sediment and 137 Cs redistribution within the catchment, including the effect of decontamination on redistribution. Fine resolution grid cells were used to model local features of the catchment, such as paddy fields adjacent to the Oginosawa River. The simulation was verified using monitoring data for river water discharge rates (r = 0.92), suspended sediment concentrations, and particulate 137 Cs concentrations (r = 0.40). Cesium-137 input to watercourses came predominantly from land adjacent to river channels and forest gullies, e.g. the paddy fields in the Ogi and Kainosaka districts, as the ground in these areas saturates during heavy rain and is easily eroded. A discrepancy between the simulation and monitoring results on the sediment discharge rate following decontamination may be explained by fast erosion occurring after decontamination. Forested areas far from the channels only made a minor contribution to 137 Cs input to watercourses, total erosion of between 0.001 and 0.1 mm from May 2011 to December 2015, as ground saturation is infrequent in these areas. The 2.3-6.9% y -1 decrease in the amount of 137 Cs in forest topsoil over the study period can be explained by radioactive decay (approximately 2.3% y -1 ), along with a migration downwards into subsoil and a small amount of export. The amount of 137 Cs available for release from land adjacent to rivers is expected to be lower in future than compared to this study period, as the simulations indicate a high depletion of inventory from these areas by the end of 2015. However continued monitoring of 137 Cs concentrations in river water over future years is advised, as

Biodiesel Production from Acidified Oils via Supercritical Methanol

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Jianxin Li

2011-12-01

Full Text Available In biodiesel production, the vegetable oil used as raw material for transesterification should be free of water and free fatty acids (FFAs, which may consume catalyst and reduce catalyst efficiency. In this work biodiesel was prepared from acidified oils (AO through a supercritical methanol route, in which the esterification of FFAs and transesterification of glyceride with methanol occurred simultaneously. The effects of the mass ratio of methanol to AO, the operation temperature as well as the water content on the FFAs conversion and glycerol yield were investigated. The results indicated that the FFAs conversion for esterification under the condition of 1:1 methanol/oil ratio, 310 °C and 15 min reaction time reached 98.7%, and the glycerol yield for transesterification under 0.25:1 methanol/oil ratio, 290 °C and 20 min reaction time reached 63.5% respectively.

Can spatial statistical river temperature models be transferred between catchments?

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Jackson, Faye L.; Fryer, Robert J.; Hannah, David M.; Malcolm, Iain A.

2017-09-01

There has been increasing use of spatial statistical models to understand and predict river temperature (Tw) from landscape covariates. However, it is not financially or logistically feasible to monitor all rivers and the transferability of such models has not been explored. This paper uses Tw data from four river catchments collected in August 2015 to assess how well spatial regression models predict the maximum 7-day rolling mean of daily maximum Tw (Twmax) within and between catchments. Models were fitted for each catchment separately using (1) landscape covariates only (LS models) and (2) landscape covariates and an air temperature (Ta) metric (LS_Ta models). All the LS models included upstream catchment area and three included a river network smoother (RNS) that accounted for unexplained spatial structure. The LS models transferred reasonably to other catchments, at least when predicting relative levels of Twmax. However, the predictions were biased when mean Twmax differed between catchments. The RNS was needed to characterise and predict finer-scale spatially correlated variation. Because the RNS was unique to each catchment and thus non-transferable, predictions were better within catchments than between catchments. A single model fitted to all catchments found no interactions between the landscape covariates and catchment, suggesting that the landscape relationships were transferable. The LS_Ta models transferred less well, with particularly poor performance when the relationship with the Ta metric was physically implausible or required extrapolation outside the range of the data. A single model fitted to all catchments found catchment-specific relationships between Twmax and the Ta metric, indicating that the Ta metric was not transferable. These findings improve our understanding of the transferability of spatial statistical river temperature models and provide a foundation for developing new approaches for predicting Tw at unmonitored locations across

Distributed modelling of hydrologic regime at three subcatchments of Kopaninský tok catchment

Science.gov (United States)

Žlábek, Pavel; Tachecí, Pavel; Kaplická, Markéta; Bystřický, Václav

2010-05-01

(runoff components - either volumes of each runoff component or occurence of baseflow) with another data set (catchment parameters - proportion of arable land, proportion of forest, proportion of vulnerable zones with high infiltration capacity, average slope, topographic index and runoff coefficient). The influence was analysed both for long-term runoff balance and selected rainfall-runoff events. Keywords: small catchment, water balance modelling, rainfall-runoff modelling, distributed deterministic model, runoff separation, sensitivity analysis

Land cover changes in catchment areas of lakes situated in headwaters of the Tyśmienica River

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Grzywna Antoni

2017-06-01

Full Text Available The paper presents the history of land cover changes in the catchment area of lakes situated in the headwaters of the Tyśmienica River. The basis of the study were topographic maps in scale 1:50 000, from 1936 and 2014. We analyzed the quantitative aspect of these changes. The study was conducted in three natural lakes (Rogóźno, Krasne, Łukcze, and in one lake transformed into a storage reservoir (Krzczeń. The technical issues of georeferencing maps in the Geographic Information System (GIS software are addressed first. In the landscape of Łęczna and Włodawa Lake District, to the end of the 19th century wetlands and bushes dominated. The first type of human pressure on this area was agriculture. Another type of pressure was recreation. In the catchment areas of studied lakes increased mainly the area of buildings and forests. Significantly increased also the length of roads and watercourses. Almost completely disappeared bushes and wastelands. In most of the analyzed basins, the area of wetlands and arable lands decreased. The probable cause of the changes in catchment use was decline in the water table, and thus overgrowing of meadows and wetlands.

Trends in concentrations and export of nitrogen in boreal forest streams

Energy Technology Data Exchange (ETDEWEB)

Sarkkola, S.; Nieminen, M. [Finnish Forest Research Inst., Vantaa (Finland); Koivusalo, H. [Aalto University School of Science and Technology, Espoo (Finland), Dept. of Civil and Environmental Engineering] [and others

2012-11-01

Temporal trends in inorganic and organic nitrogen (N) export in the stream water between 1979 and 2006 were studied in eight forested headwater catchments in eastern Finland, where an increasing air-temperature trend and a decreasing N-deposition trend has been observed since the 1980s. The Seasonal Kendall test was conducted to study if the stream water N concentrations have changed concurrently and a mixed model regression analysis was used to study which catchment characteristics and hydrometeorological variables were related to the variation in stream water N. The annual concentrations of total organic N (TON) increased at two catchments and the concentrations of nitrate (NO{sub 3}-N) and ammonium (NH{sub 4}-N) decreased at three and four catchments, respectively. The main factor explaining variation in concentrations and export of N was percentage of peatlands in a catchment. The NH{sub 4}-N concentrations were also related to the N deposition, and the exports of NO{sub 3}, NH{sub 4}, and TON to precipitation. Quantitative changes in both the N concentrations and exports were small. The results suggested relatively small changes in the N concentrations and exports between 1979 and 2006, most probably because the effects of increased air and stream water temperatures largely have been concealed behind the concurrent decrease in N deposition. (orig.)

The effects of different fertilizers on the ciliate communities of forests

International Nuclear Information System (INIS)

Lehle, E.; Funke, W.

1993-01-01

The influence of lime, mineral fertilizers and different composts on the ciliate communities (Protozoa: Ciliophora) of very acidified spruce forests were tested. In succession culture experiments species range, total numbers, abundance and dominance structure of the ciliate communities showed continued changes over a 90 day period. This method offers the opportunity not only to diagnose, but also to quantify effects of soil treatments. Investigations at the ARINUS-site Schluchsee (Black Forest) showed the following results: Liming led to a greater change in the ciliate communities than fertilization with magnesium-sulphate and ammonia-sulphate. Liming and treatment with compost, made from household garbage, and compost, made from chopped wood on the Beimerstetten site (Swabian Alb) led also to remarkably changes in the ciliate communities. The total ciliate numbers of the household garbage area were very low. In contrast, the ciliate community of the chopped wood compost areas were characterized by a great species number and high abundances of spirotrichuous ciliates, especially Halteria grandinella. (orig./UWA) [de

Measurement of dissolved Cs-137 in stream water, soil water and groundwater at Headwater Forested Catchment in Fukushima after Fukushima Dai-ichi Nuclear Power Plant Accident

Science.gov (United States)

Iwagami, Sho; Tsujimura, Maki; Onda, Yuichi; Sakakibara, Koichi; Konuma, Ryohei; Sato, Yutaro

2016-04-01

Radiocesium migration from headwater forested catchment is important perception as output from the forest which is also input to the subsequent various land use and downstream rivers after Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. In this study, dissolved Cs-137 concentration of stream water, soil water and groundwater were measured. Observations were conducted at headwater catchment in Yamakiya district, located 35 km northwest of FDNPP from April 2014 to November 2015. Stream water discharge was monitored and stream water samples were taken at main channel and sub channel. Stream water discharge was monitored by combination of parshallflume and v-notch weir. Stream water was sampled manually at steady state condition in 3-4 month interval and also intense few hours interval sampling were conducted during rainfall events using automated water sampler. Around the sub channel, it is found that there is a regularly saturated area at the bottom of the slope, temporary saturated area which saturate during the rainy season in summer and regularly dry area. 6 interval cameras were installed to monitor the changing situation of saturated area. Suction lysimeters were installed at three areas (regularly saturated area, temporary saturated area and dry area) for sampling soil water in depth of 0.1 m and 0.3 m. Boreholes were installed at three points along the sub channel. Three boreholes with depth of 3 m, 5 m and 10 m were installed at temporary saturated area, 20 m upstream of sub channel weir. Another three boreholes with depth of 3 m, 5 m and 10 m were installed at dry area, 40 m upstream of sub channel weir. And a borehole with depth of 20 m was installed at ridge of sub catchment, 52 m upstream of sub channel weir. Groundwater was sampled by electrically powered pump and groundwater level was monitored. Also suction-free lysimeter was installed at temporary saturated area for sampling the near surface subsurface water. Soil water samples were collected

Extraction of steviol glycosides from fresh Stevia using acidified water; comparison to hot water extraction, including purification

NARCIS (Netherlands)

Kootstra, A.M.J.; Huurman, Sander

2017-01-01

This report describes a practical comparison of an acidified water extraction of freshly harvested Stevia
plants (the NewFoss method) to the hot water extraction of dried Stevia plants, the industry standard. Both
extracts are subsequently purified using lab-/bench scale standard industrial

Trends in Surface Water Chemistry in Acidified Areas in Europe and North America from 1990 to 2008

Science.gov (United States)

Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analyzed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (...

Aquifers Characterization and Productivity in Ellala Catchment ...

African Journals Online (AJOL)

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Aquifers Characterization and Productivity in Ellala Catchment, Tigray, ... using geological and hydrogeological methods in Ellala catchment (296.5km. 2. ) ... Current estimates put the available groundwater ... Aquifer characterization takes into.

Assessment of surface water resources availability using catchment modeling and the results of tracer studies in the meso-scale Migina Catchment, Rwanda

Science.gov (United States)

Munyaneza, O.; Mukubwa, A.; Maskey, S.; Wenninger, J.; Uhlenbrook, S.

2013-12-01

In the last couple of years, different hydrological research projects were undertaken in the Migina catchment (243.2 km2), a tributary of the Kagera river in Southern Rwanda. These projects were aimed to understand hydrological processes of the catchment using analytical and experimental approaches and to build a pilot case whose experience can be extended to other catchments in Rwanda. In the present study, we developed a hydrological model of the catchment, which can be used to inform water resources planning and decision making. The semi-distributed hydrological model HEC-HMS (version 3.5) was used with its soil moisture accounting, unit hydrograph, liner reservoir (for base flow) and Muskingum-Cunge (river routing) methods. We used rainfall data from 12 stations and streamflow data from 5 stations, which were collected as part of this study over a period of two years (May 2009 and June 2011). The catchment was divided into five sub-catchments each represented by one of the five observed streamflow gauges. The model parameters were calibrated separately for each sub-catchment using the observed streamflow data. Calibration results obtained were found acceptable at four stations with a Nash-Sutcliffe Model Efficiency of 0.65 on daily runoff at the catchment outlet. Due to the lack of sufficient and reliable data for longer periods, a model validation (split sample test) was not undertaken. However, we used results from tracer based hydrograph separation from a previous study to compare our model results in terms of the runoff components. It was shown that the model performed well in simulating the total flow volume, peak flow and timing as well as the portion of direct runoff and base flow. We observed considerable disparities in the parameters (e.g. groundwater storage) and runoff components across the five sub-catchments, that provided insights into the different hydrological processes at sub-catchment scale. We conclude that such disparities justify the need

Pushing Boreal Headwaters: Responses of Dissolved Organic Carbon to Increased Hydro-Meteorological Forcing by Forest Harvesting

Science.gov (United States)

Schelker, J.; Grabs, T. J.; Bishop, K. H.; Laudon, H.

2012-12-01

Concentrations of dissolved organic carbon (DOC) in stream water show large variations as a response to disturbances such as forestry operations. We used a paired catchment experiment in northern Sweden which shows well quantified increases of DOC concentrations and C-exports as a result of forest harvesting. To identify the drivers of these increases, a physically-based process model (Riparian Flow Integration Model, RIM) was used to inversely simulate the DOC availability in the peat-rich riparian soils of the catchments. DOC availability in soils followed a seasonal signal paralleling the seasonality of soil-temperatures (min: February; max: August) during 2005-2011. Further, high-frequency event sampling of DOC during spring and summer seasons of 2007, 2008 and 2009, respectively, revealed that event size acted as a secondary control of DOC in streams: Spring snowmelt events (as well as one major event in 2009) showed clockwise hysteresis, whereas minor runoff episodes during summer (when DOC availability in soils was highest) were characterized by a counterclockwise behavior. The higher hydro-meteorological forcing consisting of increases of soil temperature and soil moisture after the forest removal governed additional increases in DOC availability in soils. The higher DOC concentrations observed in streams after forest harvesting can therefore be ascribed to i) the increased climatic forcing comprising higher water flows through riparian soils, ii) increased soil temperatures and soil moisture, respectively, favoring an increased production of DOC, and iii) additional variation by event size. Overall these results underline the large impact of forestry operations on stream water quality as well as DOC exports leaving managed boreal forests. Simulated and measured soil water TOC concentration profiles within the three Balsjö catchments (CC-4 = clear-cut with 67% harvest; NO-5 = 35% harvest; NR-7 = northern reference). The simulated curves represent the

Nutrient fluxes from coastal California catchments with suburban development

Science.gov (United States)

Melack, J. M.; Leydecker, A.; Beighley, E.; Robinson, T.; Coombs, S.

2005-12-01

Numerous streams originate in the mountains fringing California's coast and transport nutrients into coastal waters. In central California, these streams traverse catchments with land covers including chaparral, grazed grasslands, orchards, industrial agriculture and suburban and urban development. Fluvial nutrient concentrations and fluxes vary as a function of these land covers and as a function of considerable fluctuations in rainfall. As part of a long-term investigation of mobilization and fluvial transport of nutrients in catchments bordering the Santa Barbara Channel we have intensively sampled nutrient concentrations and measured discharge during storm and base flows in multiple catchments and subcatchments. Volume-weighted mean concentrations of nitrate generally ranged from 5 to 25 micromolar in undeveloped areas, increased to about 100 micromolar for suburban and most agricultural catchments, and were in excess of 1000 micromolar in catchments with greenhouse-based agriculture. Phosphate concentrations ranged from 2 to 20 micromolar among the catchments. These data are used to examine the premise that the suburbanized portion of the catchments is the primary source of nutrients to the streams.

Catchment Classification: Connecting Climate, Structure and Function

Science.gov (United States)

Sawicz, K. A.; Wagener, T.; Sivapalan, M.; Troch, P. A.; Carrillo, G. A.

2010-12-01

Hydrology does not yet possess a generally accepted catchment classification framework. Such a classification framework needs to: [1] give names to things, i.e. the main classification step, [2] permit transfer of information, i.e. regionalization of information, [3] permit development of generalizations, i.e. to develop new theory, and [4] provide a first order environmental change impact assessment, i.e., the hydrologic implications of climate, land use and land cover change. One strategy is to create a catchment classification framework based on the notion of catchment functions (partitioning, storage, and release). Results of an empirical study presented here connects climate and structure to catchment function (in the form of select hydrologic signatures), based on analyzing over 300 US catchments. Initial results indicate a wide assortment of signature relationships with properties of climate, geology, and vegetation. The uncertainty in the different regionalized signatures varies widely, and therefore there is variability in the robustness of classifying ungauged basins. This research provides insight into the controls of hydrologic behavior of a catchment, and enables a classification framework applicable to gauged and ungauged across the study domain. This study sheds light on what we can expect to achieve in mapping climate, structure and function in a top-down manner. Results of this study complement work done using a bottom-up physically-based modeling framework to generalize this approach (Carrillo et al., this session).

Predicting Surface Runoff from Catchment to Large Region

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Hongxia Li

2015-01-01

Full Text Available Predicting surface runoff from catchment to large region is a fundamental and challenging task in hydrology. This paper presents a comprehensive review for various studies conducted for improving runoff predictions from catchment to large region in the last several decades. This review summarizes the well-established methods and discusses some promising approaches from the following four research fields: (1 modeling catchment, regional and global runoff using lumped conceptual rainfall-runoff models, distributed hydrological models, and land surface models, (2 parameterizing hydrological models in ungauged catchments, (3 improving hydrological model structure, and (4 using new remote sensing precipitation data.

Nutrient losses in forest plantations in Sabah, Malaysia

International Nuclear Information System (INIS)

Nykvist, N.; Grip, A.; Malmer, A.

1994-01-01

Inorganic nutrients are lost from terrestrial ecosystems through the harvesting of plant products, leaching, soil erosion and volatilization of nitrogen and sulfur compounds. In this study, carried out in a tropical rain forest ecosystem in Sabah, Malaysia, losses of inorganic nutrients through log removal and runoff/leaching to stream water were compared in clear-fellings, harvested and prepared for planting in two different ways: (i) tractor logging/burning; (ii) and manual logging/no burning. The major findings of the study were that nutrient losses in stream water were reduced by 50% and growth of the planted forest was twice as fast on the catchment where soil disturbance was minimized and burning not used. Weeds were more abundant after burning, and the extra weeding needed increased costs for plantation establishment. Ways of decreasing the loss of inorganic nutrients when clear-felling tropical rain forests are discussed. 32 refs, 4 figs, 3 tabs

Predicting recovery of acidified freshwaters in Europe and Canada: an introduction

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R. C. Ferrier

2003-01-01

Full Text Available Abstract: The RECOVER: 2010 project was designed to assess the current and future anthropogenic pressures on sensitive European freshwater ecosystems. This pan–European assessment utilised a standardised predictive modelling approach to evaluate the degree of compliance with respect to the restoration of acidified waters by 2016, as specified under the EU Water Framework Directive (WFD, and evaluated the environmental benefits of proposed UN-ECE protocols on emissions control. Between 1970 and 2000, observations and model simulations show a significant decline in acidic surface water in all regions of Europe. This demonstrated the success of policies aimed at reducing emission of acidifying compounds. The nature and extent of future regional recovery from acidification is, however, dependent upon the historical pattern of deposition, regional ecosystem characteristics and the role of confounding factors, which may delay the onset of recovery or the magnitude of response. Model predictions to 2010 and beyond emphasise the continued benefit of currently proposed reductions, as reflected by the degree of recovery of freshwater ecosystems. A key component was to link such hydrochemical recovery with ecological response, and the project aimed to evaluate this against current WFD criteria of “good status' and “reference conditions'. The RECOVER: 2010 project research has also played a major role in defining the dynamic modelling outputs which will be required to support the review of the Gothenburg Protocol within the work of the UN-ECE CLRTAP Working Group on Effects (WGE, and model outputs have been made available to a range of national agencies throughout Europe. Keyword: recovery, acidification, modelling, policy, good status, reference conditions

High resolution climate scenarios for snowmelt modelling in small alpine catchments

Science.gov (United States)

Schirmer, M.; Peleg, N.; Burlando, P.; Jonas, T.

2017-12-01

Snow in the Alps is affected by climate change with regard to duration, timing and amount. This has implications with respect to important societal issues as drinking water supply or hydropower generation. In Switzerland, the latter received a lot of attention following the political decision to phase out of nuclear electricity production. An increasing number of authorization requests for small hydropower plants located in small alpine catchments was observed in the recent years. This situation generates ecological conflicts, while the expected climate change poses a threat to water availability thus putting at risk investments in such hydropower plants. Reliable high-resolution climate scenarios are thus required, which account for small-scale processes to achieve realistic predictions of snowmelt runoff and its variability in small alpine catchments. We therefore used a novel model chain by coupling a stochastic 2-dimensional weather generator (AWE-GEN-2d) with a state-of-the-art energy balance snow cover model (FSM). AWE-GEN-2d was applied to generate ensembles of climate variables at very fine temporal and spatial resolution, thus providing all climatic input variables required for the energy balance modelling. The land-surface model FSM was used to describe spatially variable snow cover accumulation and melt processes. The FSM was refined to allow applications at very high spatial resolution by specifically accounting for small-scale processes, such as a subgrid-parametrization of snow covered area or an improved representation of forest-snow processes. For the present study, the model chain was tested for current climate conditions using extensive observational dataset of different spatial and temporal coverage. Small-scale spatial processes such as elevation gradients or aspect differences in the snow distribution were evaluated using airborne LiDAR data. 40-year of monitoring data for snow water equivalent, snowmelt and snow-covered area for entire

Soil solution and extractable soil nitrogen response to climate change in two boreal forest ecosystems

NARCIS (Netherlands)

Verburg, P.H.

2005-01-01

Several studies show that increases in soil temperature result in higher N mineralization rates in soils. It is, however, unclear if additional N is taken up by the vegetation or accumulates in the soil. To address this question two small, forested catchments in southern Norway were experimentally

Debris flows on forested cones – reconstruction and comparison of frequencies in two catchments in Val Ferret, Switzerland

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M. Bollschweiler

2007-01-01

Full Text Available Debris flows represent a major threat to infrastructure in many regions of the Alps. Since systematic acquisition of data on debris-flow events in Switzerland only started after the events of 1987, there is a lack of historical knowledge on earlier debris-flow events for most torrents. It is therefore the aim of this study to reconstruct the debris-flow activity for the Reuse de Saleinaz and the La Fouly torrents in Val Ferret (Valais, Switzerland. In total, 556 increment cores from 278 heavily affected Larix decidua Mill., Picea abies (L. Karst. and Pinus sylvestris L. trees were sampled. Trees on the cone of Reuse de Saleinaz show an average age of 123 years at sampling height, with the oldest tree aged 325 years. Two periods of intense colonization (the 1850s–1880s and the 1930s–1950s are observed, probably following high-magnitude events that would have eliminated the former forest stand. Trees on the cone of Torrent de la Fouly indicate an average age of 119 years. As a whole, tree-ring analyses allowed assessment of 333 growth disturbances belonging to 69 debris-flow events. While the frequency for the Reuse de Saleinaz study site comprises 39 events between AD 1743 and 2003, 30 events could be reconstructed at the Torrent de la Fouly for the period 1862–2003. Even though the two study sites evince considerably different characteristics in geology, debris-flow material and catchment morphology, they apparently produce debris flows at similar recurrence intervals. We suppose that, in the study region, the triggering and occurrence of events is transport-limited rather than weathering-limited.

The Influence of temporal sampling regime on the WFD classification of catchments within the Eden Demonstration Test Catchment Project

Science.gov (United States)

Jonczyk, Jennine; Haygarth, Phil; Quinn, Paul; Reaney, Sim

2014-05-01

A high temporal resolution data set from the Eden Demonstration Test Catchment (DTC) project is used to investigate the processes causing pollution and the influence of temporal sampling regime on the WFD classification of three catchments. This data highlights WFD standards may not be fit for purpose. The Eden DTC project is part of a UK government-funded project designed to provide robust evidence regarding how diffuse pollution can be cost-effectively controlled 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 approximately 10 km2 each, 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 sensors providing continuous real time data. The data set, which includes Total Phosphorus and Total Reactive Phosphorus, Nitrate, Ammonium, pH, Conductivity, Turbidity and Chlorophyll a reveals the frequency and duration of nutrient concentration target exceedance which arises from the prevalence of storm events of increasing magnitude. This data set is sub-sampled at different time intervals to explore how different sampling regimes affects our understanding of nutrient dynamics and the ramification of the different regimes to WFD chemical status. This presentation seeks to identify an optimum temporal resolution of data for effective catchment management and to question the usefulness of the WFD status metric for determining health of a system. Criteria based on high frequency short duration events needs to be accounted for.

Input-output balances of acids, heavy metals and nutrients, and compartments of accumulation and depletion in forest ecosystems

International Nuclear Information System (INIS)

Mayer, R.

1989-01-01

Forest damage and decline are the consequence of several stress factors acting upon forest ecosystems in various combinations and degrees. Impact of atmospheric pollutants is certainly one of the most prominent of these factors. Regional comparion is facilitated by considering groups of atmospheric substances. We distinguish: 1. Acids and acidifying substances, 2. Heavy metals and 3. Nutrients: N, P, K, Ca, Mg, S. Forest decline has to be recognized as an expression of changes within the forest ecosystem, changes which must be accompanied by a non-steady state of the material balance. The best way to investigate changes in the material balance is to look at input and output of matter to the ecosystems. A positive balance (input > output) over a period of more than one year means accumulation, negative balance (input < output) means depletion of a substance. Based upon several case studies (Subjects I, K), we come to a typification of the material balance at any individual site which is defined by the immission/deposition situation on the one hand, by the geological-pedological site characteristics on the other hand. (orig.VT)

Changes in faunal and vegetation communities along a soil calcium gradient in northern hardwood forests

Science.gov (United States)

Beier, Colin M.; Woods, Anne M.; Hotopp, Kenneth P.; Gibbs, James P.; Mitchell, Myron J.; Dovciak, Martin; Leopold, Donald J.; Lawrence, Gregory B.; Page, Blair D.

2012-01-01

Depletion of Ca from forest soils due to acidic deposition has had potentially pervasive effects on forest communities, but these impacts remain largely unknown. Because snails, salamanders, and plants play essential roles in the Ca cycle of northern hardwood forests, we hypothesized that their community diversity, abundance, and structure would vary with differences in biotic Ca availability. To test this hypothesis, we sampled 12 upland hardwood forests representing a soil Ca gradient in the Adirondack Mountains, New York (USA), where chronic deposition has resulted in acidified soils but where areas of well-buffered soils remain Ca rich due to parent materials. Along the gradient of increasing soil [Ca2+], we observed increasing trends in snail community richness and abundance, live biomass of redback salamanders (Plethodon cinereus (Green, 1818)), and canopy tree basal area. Salamander communities were dominated by mountain dusky salamanders (Desmognathus ochrophaeus Cope, 1859) at Ca-poor sites and changed continuously along the Ca gradient to become dominated by redback salamanders at the Ca-rich sites. Several known calciphilic species of snails and plants were found only at the highest-Ca sites. Our results indicated that Ca availability, which is shaped by geology and acidic deposition inputs, influences northern hardwood forest ecosystems at multiple trophic levels, although the underlying mechanisms require further study.

Uncertainty in hydrological signatures for gauged and ungauged catchments

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Westerberg, Ida K.; Wagener, Thorsten; Coxon, Gemma; McMillan, Hilary K.; Castellarin, Attilio; Montanari, Alberto; Freer, Jim

2016-03-01

Reliable information about hydrological behavior is needed for water-resource management and scientific investigations. Hydrological signatures quantify catchment behavior as index values, and can be predicted for ungauged catchments using a regionalization procedure. The prediction reliability is affected by data uncertainties for the gauged catchments used in prediction and by uncertainties in the regionalization procedure. We quantified signature uncertainty stemming from discharge data uncertainty for 43 UK catchments and propagated these uncertainties in signature regionalization, while accounting for regionalization uncertainty with a weighted-pooling-group approach. Discharge uncertainty was estimated using Monte Carlo sampling of multiple feasible rating curves. For each sampled rating curve, a discharge time series was calculated and used in deriving the gauged signature uncertainty distribution. We found that the gauged uncertainty varied with signature type, local measurement conditions and catchment behavior, with the highest uncertainties (median relative uncertainty ±30-40% across all catchments) for signatures measuring high- and low-flow magnitude and dynamics. Our regionalization method allowed assessing the role and relative magnitudes of the gauged and regionalized uncertainty sources in shaping the signature uncertainty distributions predicted for catchments treated as ungauged. We found that (1) if the gauged uncertainties were neglected there was a clear risk of overconditioning the regionalization inference, e.g., by attributing catchment differences resulting from gauged uncertainty to differences in catchment behavior, and (2) uncertainty in the regionalization results was lower for signatures measuring flow distribution (e.g., mean flow) than flow dynamics (e.g., autocorrelation), and for average flows (and then high flows) compared to low flows.

Conditional flood frequency and catchment state: a simulation approach

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Brettschneider, Marco; Bourgin, François; Merz, Bruno; Andreassian, Vazken; Blaquiere, Simon

2017-04-01

Catchments have memory and the conditional flood frequency distribution for a time period ahead can be seen as non-stationary: it varies with the catchment state and climatic factors. From a risk management perspective, understanding the link of conditional flood frequency to catchment state is a key to anticipate potential periods of higher flood risk. Here, we adopt a simulation approach to explore the link between flood frequency obtained by continuous rainfall-runoff simulation and the initial state of the catchment. The simulation chain is based on i) a three state rainfall generator applied at the catchment scale, whose parameters are estimated for each month, and ii) the GR4J lumped rainfall-runoff model, whose parameters are calibrated with all available data. For each month, a large number of stochastic realizations of the continuous rainfall generator for the next 12 months are used as inputs for the GR4J model in order to obtain a large number of stochastic realizations for the next 12 months. This process is then repeated for 50 different initial states of the soil moisture reservoir of the GR4J model and for all the catchments. Thus, 50 different conditional flood frequency curves are obtained for the 50 different initial catchment states. We will present an analysis of the link between the catchment states, the period of the year and the strength of the conditioning of the flood frequency compared to the unconditional flood frequency. A large sample of diverse catchments in France will be used.

Application of LiDAR to hydrologic flux estimation in Australian eucalypt forests (Invited)

Science.gov (United States)

Lane, P. N.; Mitchell, P. J.; Jaskierniak, D.; Hawthorne, S. N.; Griebel, A.

2013-12-01

The potential of LiDAR in ecohydrology is significant as characterising catchment vegetation is crucial to accurate estimation of evapotranspiration (ET). While this may be done at large scales for model parameterisation, stand-scale applications are equally appropriate where traditional methods of measurement of LAI or sapwood areas are time consuming and reliant on assumptions of representative sampling. This is particularly challenging in mountain forests where aspect, soil properties and energy budgets can vary significantly, reflected in the vegetation or where there are changes in the spatial distribution of structural attributes following disturbance. Recent research has investigated the spatial distribution of ET in a eucalypt forest in SE Australia using plot-scale sapflow, interception and forest floor ET measurements. LiDAR was used scale up these measurements. LiDAR (0.16 m scanner footprint) canopy indices were correlated via stepwise regression with 4 water use scalars: basal area (BA), sapwood area (SA), leaf area index (LAI) and canopy coverage (C), with Hmed, Hmean, H80, H95 the best predictors. Combining these indices with empirical relationships between SA and BA, and SA and transpiration (T), and inventory plot 'ground truthing' transpiration was estimated across the 1.3 km2 catchment. Interception was scaled via the Gash model with LiDAR derived inputs. The up-scaling showed a significant variability in the spatial distribution of ET, related to the distribution of SA. The use of LiDAR meant scaling could be achieved at an appropriate spatial scale (20 x 20 m) to the measurements. The second example is the use of airborne LiDAR in developing growth forest models for hydrologic modeling. LiDAR indices were used to stratify multilayered forests using mixed-effect models with a wide range of theoretical distribution functions. When combined with historical plot-scale inventory data we show demonstrated improved growth modeling over traditional

Catchments' hedging strategy on evapotranspiration for climatic variability

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Ding, W.; Zhang, C.; Li, Y.; Tang, Y.; Wang, D.; Xu, B.

2017-12-01

Hydrologic responses to climate variability and change are important for human society. Here we test the hypothesis that natural catchments utilize hedging strategies for evapotranspiration and water storage carryover with uncertain future precipitation. The hedging strategy for evapotranspiration in catchments under different levels of water availability is analytically derived from the economic perspective. It is found that there exists hedging between evapotranspiration for current and future only with a portion of water availability. Observation data sets of 160 catchments in the United States covering the period from 1983 to 2003 demonstrate the existence of hedging in catchment hydrology and validate the proposed hedging strategies. We also find that more water is allocated to carryover storage for hedging against the future evapotranspiration risk in the catchments with larger aridity indexes or with larger uncertainty in future precipitation, i.e., long-term climate and precipitation variability control the degree of hedging.

Effects of acidifying pig diets on emissions of ammonia, methane and sulfur from slurry during storage

DEFF Research Database (Denmark)

Eriksen, Jørgen; Nørgaard, Jan Værum; Poulsen, Hanne Damgaard

2014-01-01

and feces were collected separately from twenty-four pigs fed one of four diets (Control, +BA, +CaCl2, +BA+CaCl2) in metabolic cages, and mixed as slurry. During 103 days of storage, all acidifying diets consistently reduced pH in the slurry by 0.4 - 0.6 units. There was a strong relationship between slurry...

Catchment Dispersion Mechanisms in an Urban Context

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Gironas, J. A.; Mejia, A.; Rossel, F.; Rinaldo, A.; Rodriguez, F.

2014-12-01

Dispersion mechanisms have been examined in-depth in natural catchments in previous studies. However, these dispersion mechanisms have been studied little in urban catchments, where artificial transport elements and morphological arrangements are expected to modify travel times and mobilize excess rainfall from spatially distributed impervious sites. Thus, these features can modify the variance of the catchment's travel times and hence the total dispersion. This work quantifies the dispersion mechanisms in an urban catchment using the theory of transport by travel times as represented by the Urban Morpho-climatic Instantaneous Unit Hydrograph (U-McIUH) model. This model computes travel times based on kinematic wave theory and accounts explicitly for the path heterogeneities and altered connectivity patterns characteristic of an urban drainage network. The analysis is illustrated using the Aubinière urban catchment (France) as a case study. We found that kinematic dispersion is dominant for small rainfall intensities, whereas geomorphologic dispersion becomes more dominant for larger intensities. The total dispersion scales with the drainage area in a power law fashion. The kinematic dispersion is dominant across spatial scales up to a threshold of approximately 2-3 km2, after which the geomorphologic dispersion becomes more dominant. Overall, overland flow is responsible for most of the dispersion, while conduits tend to counteract the increase of the geomorphologic dispersion with a negative kinematic dispersion. Further studies with other catchments are needed to assess whether the latter is a general feature of urban drainage networks.

Runoff generating processes in adjacent tussock grassland and pine plantation catchments as indicated by mean transit time estimation using tritium

Directory of Open Access Journals (Sweden)

M. K. Stewart

2010-06-01

Full Text Available The east Otago uplands of New Zealand's South Island have long been studied because of the environmental consequences of converting native tussock grasslands to other land covers, notably forestry and pasture for stock grazing. Early studies showed that afforestation substantially reduced annual water yield, stream peak flows, and 7-day low flows, mainly as a consequence of increased interception. Tritium measurements have indicated that surprisingly old water is present in catchments GH1 and GH2, and the small headwater wetland and catchment (GH5, and contributes strongly to baseflow. The data have been simulated assuming the presence of two types of water in the baseflow, young water from shallow aquifers connecting hillside regolith with the stream, and old water from deep bedrock aquifers, respectively. The mean transit time of the young water is approximately one month, while that of the old water is 25–26 years as revealed by the presence of tritium originating from the bomb-peak in NZ rainfall in late 1960s and early 1970s. Such a long transit time indicates slow release from groundwater reservoirs within the bedrock, which constitute by far the larger of the water stores. Comparison of the results from catchments GH1 (tussock and GH2 (pine forest suggests that about equal quantities of water (85 mm/a are contributed from the deep aquifers in the two catchments, although runoff from the shallow aquifers has been strongly reduced by afforestation in GH2. This study has revealed the presence of a long transit time component of water in runoff in a catchment with crystalline metamorphic bedrock.

Runoff generating processes in adjacent tussock grassland and pine plantation catchments as indicated by mean transit time estimation using tritium

Science.gov (United States)

Stewart, M. K.; Fahey, B. D.

2010-06-01

The east Otago uplands of New Zealand's South Island have long been studied because of the environmental consequences of converting native tussock grasslands to other land covers, notably forestry and pasture for stock grazing. Early studies showed that afforestation substantially reduced annual water yield, stream peak flows, and 7-day low flows, mainly as a consequence of increased interception. Tritium measurements have indicated that surprisingly old water is present in catchments GH1 and GH2, and the small headwater wetland and catchment (GH5), and contributes strongly to baseflow. The data have been simulated assuming the presence of two types of water in the baseflow, young water from shallow aquifers connecting hillside regolith with the stream, and old water from deep bedrock aquifers, respectively. The mean transit time of the young water is approximately one month, while that of the old water is 25-26 years as revealed by the presence of tritium originating from the bomb-peak in NZ rainfall in late 1960s and early 1970s. Such a long transit time indicates slow release from groundwater reservoirs within the bedrock, which constitute by far the larger of the water stores. Comparison of the results from catchments GH1 (tussock) and GH2 (pine forest) suggests that about equal quantities of water (85 mm/a) are contributed from the deep aquifers in the two catchments, although runoff from the shallow aquifers has been strongly reduced by afforestation in GH2. This study has revealed the presence of a long transit time component of water in runoff in a catchment with crystalline metamorphic bedrock.

Distribution, Fraction, and Ecological Assessment of Heavy Metals in Sediment-Plant System in Mangrove Forest, South China Sea

Science.gov (United States)

Li, Ruili; Chai, Minwei; Qiu, Guo Yu

2016-01-01

Overlying water, sediment, rhizosphere sediment and mangrove seedlings in the Futian mangrove forest were analyzed for heavy metals. The results showed that mangrove plant acidified sediment and increased organic matter contents. Except for chromium (Cr), nickel (Ni) and copper (Cu) in Aegiceras corniculatum sediment, heavy metals in all sediments were higher than in overlying water, rhizosphere sediment and mangrove root. Heavy metals in Avicennia marina sediments were higher than other sediments. The lower heavy metal biological concentration factors (BCFs) and translocation factors (TFs) indicated that mangrove plant adopted exclusion strategy. The geo-accumulation index, potential ecological risk index and risk assessment code (RAC) demonstrated that heavy metals have posed a considerable ecological risk, especially for cadmium (Cd). Heavy metals (Cr, Ni, Cu and Cd) mainly existed in the reducible fractions. These findings provide actual heavy metal accumulations in sediment-plant ecosystems in mangrove forest, being important in designing the long-term management and conservation policies for managers of mangrove forest. PMID:26800267

Water and forests in the Mediterranean hot climate zone: a review based on a hydraulic interpretation of tree functioning

Energy Technology Data Exchange (ETDEWEB)

Soares David, T.; Assunção Pinto, C.; Nadezhdina, N.; Soares David, J.

2016-07-01

Aim of the study: Water scarcity is the main limitation to forest growth and tree survival in the Mediterranean hot climate zone. This paper reviews literature on the relations between water and forests in the region, and their implications on forest and water resources management. The analysis is based on a hydraulic interpretation of tree functioning. Area of the study: The review covers research carried out in the Mediterranean hot climate zone, put into perspective of wider/global research on the subject. The scales of analysis range from the tree to catchment levels. Material and Methods: For literature review we used Sc opus, Web of Science and Go ogle Scholar as bibliographic databases. Data from two Quercus suber sites in Portugal were used for illustrative purposes. Main results: We identify knowledge gaps and discuss options to better adapt forest management to climate change under a tree water use/availability perspective. Forest management is also discussed within the wider context of catchment water balance: water is a constraint for biomass production, but also for other human activities such as urban supply, industry and irrigated agriculture. Research highlights: Given the scarce and variable (in space and in time) water availability in the region, further research is needed on: mapping the spatial heterogeneity of water availability to trees; adjustment of tree density to local conditions; silviculture practices that do not damage soil properties or roots; irrigation of forest plantations in some specific areas; tree breeding. Also, a closer cooperation between forest and water managers is needed. (Author)

Sediment transport dynamics in steep, tropical volcanic catchments

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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 (transform. Owing to volcanism and seismic activity, landslides and other mass movements frequently occur. These processes are amplified by high intensity precipitation inputs resulting in significant, but 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

Picturing and modelling catchments by representative hillslopes

Science.gov (United States)

Loritz, Ralf; Hassler, Sibylle; Jackisch, Conrad; Zehe, Erwin

2016-04-01

Hydrological modelling studies often start with a qualitative sketch of the hydrological processes of a catchment. These so-called perceptual models are often pictured as hillslopes and are generalizations displaying only the dominant and relevant processes of a catchment or hillslope. The problem with these models is that they are prone to become too much predetermined by the designer's background and experience. Moreover it is difficult to know if that picture is correct and contains enough complexity to represent the system under study. Nevertheless, because of their qualitative form, perceptual models are easy to understand and can be an excellent tool for multidisciplinary exchange between researchers with different backgrounds, helping to identify the dominant structures and processes in a catchment. In our study we explore whether a perceptual model built upon an intensive field campaign may serve as a blueprint for setting up representative hillslopes in a hydrological model to reproduce the functioning of two distinctly different catchments. We use a physically-based 2D hillslope model which has proven capable to be driven by measured soil-hydrological parameters. A key asset of our approach is that the model structure itself remains a picture of the perceptual model, which is benchmarked against a) geo-physical images of the subsurface and b) observed dynamics of discharge, distributed state variables and fluxes (soil moisture, matric potential and sap flow). Within this approach we are able to set up two behavioral model structures which allow the simulation of the most important hydrological fluxes and state variables in good accordance with available observations within the 19.4 km2 large Colpach catchment and the 4.5 km2 large Wollefsbach catchment in Luxembourg without the necessity of calibration. This corroborates, contrary to the widespread opinion, that a) lower mesoscale catchments may be modelled by representative hillslopes and b) physically

Advancing Land-Sea Conservation Planning: Integrating Modelling of Catchments, Land-Use Change, and River Plumes to Prioritise Catchment Management and Protection.

Science.gov (United States)

Álvarez-Romero, Jorge G; Pressey, Robert L; Ban, Natalie C; Brodie, Jon

2015-01-01

Human-induced changes to river loads of nutrients and sediments pose a significant threat to marine ecosystems. Ongoing land-use change can further increase these loads, and amplify the impacts of land-based threats on vulnerable marine ecosystems. Consequently, there is a need to assess these threats and prioritise actions to mitigate their impacts. A key question regarding prioritisation is whether actions in catchments to maintain coastal-marine water quality can be spatially congruent with actions for other management objectives, such as conserving terrestrial biodiversity. In selected catchments draining into the Gulf of California, Mexico, we employed Land Change Modeller to assess the vulnerability of areas with native vegetation to conversion into crops, pasture, and urban areas. We then used SedNet, a catchment modelling tool, to map the sources and estimate pollutant loads delivered to the Gulf by these catchments. Following these analyses, we used modelled river plumes to identify marine areas likely influenced by land-based pollutants. Finally, we prioritised areas for catchment management based on objectives for conservation of terrestrial biodiversity and objectives for water quality that recognised links between pollutant sources and affected marine areas. Our objectives for coastal-marine water quality were to reduce sediment and nutrient discharges from anthropic areas, and minimise future increases in coastal sedimentation and eutrophication. Our objectives for protection of terrestrial biodiversity covered species of vertebrates. We used Marxan, a conservation planning tool, to prioritise interventions and explore spatial differences in priorities for both objectives. Notable differences in the distributions of land values for terrestrial biodiversity and coastal-marine water quality indicated the likely need for trade-offs between catchment management objectives. However, there were priority areas that contributed to both sets of objectives. Our

Adaptation of chemical methods of analysis to the matrix of pyrite-acidified mining lakes

International Nuclear Information System (INIS)

Herzsprung, P.; Friese, K.

2000-01-01

Owing to the unusual matrix of pyrite-acidified mining lakes, the analysis of chemical parameters may be difficult. A number of methodological improvements have been developed so far, and a comprehensive validation of methods is envisaged. The adaptation of the available methods to small-volume samples of sediment pore waters and the adaptation of sensitivity to the expected concentration ranges is an important element of the methods applied in analyses of biogeochemical processes in mining lakes [de

Catchment-scale groundwater recharge and vegetation water use efficiency

Science.gov (United States)

Troch, P. A. A.; Dwivedi, R.; Liu, T.; Meira, A.; Roy, T.; Valdés-Pineda, R.; Durcik, M.; Arciniega, S.; Brena-Naranjo, J. A.

2017-12-01

Precipitation undergoes a two-step partitioning when it falls on the land surface. At the land surface and in the shallow subsurface, rainfall or snowmelt can either runoff as infiltration/saturation excess or quick subsurface flow. The rest will be stored temporarily in the root zone. From the root zone, water can leave the catchment as evapotranspiration or percolate further and recharge deep storage (e.g. fractured bedrock aquifer). Quantifying the average amount of water that recharges deep storage and sustains low flows is extremely challenging, as we lack reliable methods to quantify this flux at the catchment scale. It was recently shown, however, that for semi-arid catchments in Mexico, an index of vegetation water use efficiency, i.e. the Horton index (HI), could predict deep storage dynamics. Here we test this finding using 247 MOPEX catchments across the conterminous US, including energy-limited catchments. Our results show that the observed HI is indeed a reliable predictor of deep storage dynamics in space and time. We further investigate whether the HI can also predict average recharge rates across the conterminous US. We find that the HI can reliably predict the average recharge rate, estimated from the 50th percentile flow of the flow duration curve. Our results compare favorably with estimates of average recharge rates from the US Geological Survey. Previous research has shown that HI can be reliably estimated based on aridity index, mean slope and mean elevation of a catchment (Voepel et al., 2011). We recalibrated Voepel's model and used it to predict the HI for our 247 catchments. We then used these predicted values of the HI to estimate average recharge rates for our catchments, and compared them with those estimated from observed HI. We find that the accuracies of our predictions based on observed and predicted HI are similar. This provides an estimation method of catchment-scale average recharge rates based on easily derived catchment

Effect of Hydrograph Separation on Suspended Sediment Concentration Predictions in a Forested Headwater with Thick Soil and Weathered Gneiss Layers

Directory of Open Access Journals (Sweden)

Naoki Kabeya

2014-06-01

Full Text Available Two-component hydrograph separation using oxygen-18 concentrations was conducted at a sediment runoff observation weir installed in a small subcatchment of a forested gneiss catchment in Japan. The mean soil thickness of this catchment is 7.27 m, which comprises 3.29 m of brown forest soil (A and B layers and a 3.98-m layer of heavily weathered gneiss. Data were collected for a storm on 20–21 May 2003, and the percentage of event water separated by the stable isotope ratio in comparison with the total rainfall amount was about 1%. This value is within the ratio of a riparian zone in a drainage area. Temporal variation of suspended sediment concentration exhibited higher correlation with the event water component than with the total runoff or pre-event water component. This shows that the riparian zone causes rainwater to flow out quickly during a rain event, and that this is an important area of sediment production and transportation in a forested headwater with thick soil and weathered gneiss layers.

Probability based hydrologic catchments of the Greenland Ice Sheet

Science.gov (United States)

Hudson, B. D.

2015-12-01

Greenland Ice Sheet melt water impacts ice sheet flow dynamics, fjord and coastal circulation, and sediment and biogeochemical fluxes. Melt water exiting the ice sheet also is a key term in its mass balance. Because of this, knowledge of the area of the ice sheet that contributes melt water to a given outlet (its hydrologic catchment) is important to many ice sheet studies and is especially critical to methods using river runoff to assess ice sheet mass balance. Yet uncertainty in delineating ice sheet hydrologic catchments is a problem that is rarely acknowledged. Ice sheet catchments are delineated as a function of both basal and surface topography. While surface topography is well known, basal topography is less certain because it is dependent on radar surveys. Here, I a present a Monte Carlo based approach to delineating ice sheet catchments that quantifies the impact of uncertain basal topography. In this scheme, over many iterations I randomly vary the ice sheet bed elevation within published error bounds (using Morlighem et al., 2014 bed and bed error datasets). For each iteration of ice sheet bed elevation, I calculate the hydraulic potentiometric surface and route water over its path of 'steepest' descent to delineate the catchment. I then use all realizations of the catchment to arrive at a probability map of all major melt water outlets in Greenland. I often find that catchment size is uncertain, with small, random perturbations in basal topography leading to large variations in catchments size. While some catchments are well defined, others can double or halve in size within published basal topography error bars. While some uncertainty will likely always remain, this work points to locations where studies of ice sheet hydrology would be the most successful, allows reinterpretation of past results, and points to where future radar surveys would be most advantageous.

Assessing the protection function of Alpine forest ecosystems using BGC modelling theory

Science.gov (United States)

Pötzelsberger, E.; Hasenauer, H.; Petritsch, R.; Pietsch, S. A.

2009-04-01

The purpose of this study was to assess the protection function of forests in Alpine areas by modelling the flux dynamics (water, carbon, nutrients) within a watershed as they may depend on the vegetation pattern and forest management impacts. The application case for this study was the catchment Schmittenbach, located in the province of Salzburg. Data available covered the hydrology (rainfall measurements from 1981 to 1998 and runoff measurements at the river Schmittenbach from 1981 to 2005), vegetation dynamics (currently 69% forest, predominantly Norway Spruce). The method of simulating the forest growth and water outflow was validated. For simulations of the key ecosystem processes (e.g. photosynthesis, carbon and nitrogen allocation in the different plant parts, litter fall, mineralisation, tree water uptake, transpiration, rainfall interception, evaporation, snow accumulation and snow melt, outflow of spare water) the biogeochemical ecosystem model Biome-BGC was applied. Relevant model extensions were the tree species specific parameter sets and the improved thinning regime. The model is sensitive to site characteristics and needs daily weather data and information on the atmospheric composition, which makes it sensitive to higher CO2-levels and climate change. For model validation 53 plots were selected covering the full range of site quality and stand age. Tree volume and soil was measured and compared with the respective model results. The outflow for the watershed was predicted by combining the simulated forest-outflow (derived from plot-outflow) with the outflow from the non-forest area (calculated with a fixed outflow/rainfall coefficient (OC)). The analysis of production and water related model outputs indicated that mechanistic modelling can be used as a tool to assess the performance of Alpine protection forests. The Water Use Efficiency (WUE), the ratio of Net primary production (NPP) and Transpiration, was found the highest for juvenile stands (�

Assessment of water availability in Chindwinn catchment

International Nuclear Information System (INIS)

Phyu Oo Khin; Ohn Gyaw

2001-01-01

A study of water balance over Chindwinn Catchment has been carried out by using three decades of available climatological and hydrological data (i.e. from 1967). The study was based on the monthly, annual and normal values. Actual evapotranspiration (AET) computed by as well as on the using Penman (1963) as well as Hargreaves (1985) methods. Some of the reliable data of evaporation at the stations were also used to estimate actual evaporation with the pancoefficient value 0.7. The values of actual evapotranspiration estimated by Hargreaves method was lower than the values estimated by Penman, but most followed the same significant trend. The soil moisture deficiency generally occurs during November and April. A few cases of soil moisture deficiency do occur in August, September and October. However, on the overall availability of water in the catchment is quite promising. The residual resulted from the water balance estimation may be assumed as soil moisture in the catchment by neglecting some losses from the catchment. (author)

Humus layer is the main locus of secondary SO4 production in boreal forests

Science.gov (United States)

Houle, Daniel; Marty, Charles; Duchesne, Louis; Gagnon, Christian

2014-02-01

Identifying the sources of S exported from catchments and the reactivity of the large soil organic S pool is crucial to understand the mid- or long-term response of forested catchments to decreasing atmospheric S deposition and global warming. Sulfur fluxes as well as S and O isotopes of SO4 were measured in precipitation, throughfall, soil solutions and streams at two boreal forest catchments respectively dominated by black spruce (BS) and balsam fir (BF) in Quebec, Canada. Overall, δ34S-SO4 signature showed relatively small variations among various solution types. However, at both sites, δ18O-SO4 in precipitation (averages of 10.5-11.1‰) was decreased by 3.5-3.6‰ in throughfall because of the production of secondary SO4 through oxidation of SO2 deposited on the canopy. Throughfall δ18O-SO4 was decreased by a further 5.4-6.6‰ in the solution leaving the humus layer which was attributed to the production of secondary SO4 under the action of soil microorganisms through the oxidation of organic S during which the S atom acquired O from water and gaseous O2 present in the soil. A mixing equation based on known isotopic signature of each source suggested that ˜67-81% of the S-SO4 leaving the catchments had interacted with the canopy and the humus layer. The stability of δ18O-SO4 in the mineral soil solution and in the stream of both sites, suggests that SO4 does not undergo reduction-oxidation cycles after its passage through the humus layer. Despite its huge size, the organic S reservoir within the mineral soil would be largely inert. Given the chemical nature of SO4 transformation in the canopy, the humus layer would be responsible for nearly 100% of the biological production of secondary SO4 in the whole watershed at both sites. Taking into account the substantial production of dissolved organic S in the humus layer further emphasizes the crucial importance of the latter in the S cycling of boreal forests.

Catchment-wide weathering and erosion rates of mafic, ultramafic, and granitic rock from cosmogenic meteoric 10Be/9Be ratios

Science.gov (United States)

Dannhaus, N.; Wittmann, H.; Krám, P.; Christl, M.; von Blanckenburg, F.

2018-02-01

Quantifying rates of weathering and erosion of mafic rocks is essential for estimating changes to the oceans alkalinity budget that plays a significant role in regulating atmospheric CO2 levels. In this study, we present catchment-wide rates of weathering, erosion, and denudation measured with cosmogenic nuclides in mafic and ultramafic rock. We use the ratio of the meteoric cosmogenic nuclide 10Be, deposited from the atmosphere onto the weathering zone, to stable 9Be, a trace metal released by silicate weathering. We tested this approach in stream sediment and water from three upland forested catchments in the north-west Czech Republic. The catchments are underlain by felsic (granite), mafic (amphibolite) and ultramafic (serpentinite) lithologies. Due to acid rain deposition in the 20th century, the waters in the granite catchment exhibit acidic pH, whereas waters in the mafic catchments exhibit neutral to alkaline pH values due to their acid buffering capability. The atmospheric depositional 10Be flux is estimated to be balanced with the streams' dissolved and particulate meteoric 10Be export flux to within a factor of two. We suggest a correlation method to derive bedrock Be concentrations, required as an input parameter, which are highly heterogeneous in these small catchments. Derived Earth surface metrics comprise (1) Denudation rates calculated from the 10Be/9Be ratio of the "reactive" Be (meaning sorbed to mineral surfaces) range between 110 and 185 t km-2 y-1 (40 and 70 mm ky-1). These rates are similar to denudation rates we obtained from in situ-cosmogenic 10Be in quartz minerals present in the bedrock or in quartz veins in the felsic and the mafic catchment. (2) The degree of weathering, calculated from the fraction of 9Be released from primary minerals as a new proxy, is about 40-50% in the mafic catchments, and 10% in the granitic catchment. Lastly, (3) erosion rates were calculated from 10Be concentrations in river sediment and corrected for sorting

Factors Influencing Water Resource Governance among Pastoral Community at Mkondoa Sub-Catchment Morogoro Region Tanzania

Directory of Open Access Journals (Sweden)

Yeremia Yohana Masifia

2017-06-01

Full Text Available The importance of proper Water Resource Management with greater emphasis on ensuring sustainability quality accountability and community participation has become imminent as water resources increasingly become scarce Harvey et al 2007. Water resources management in Tanzania is governed under the National Water Policy of 2002 and Water Resources Management Act No.11 of year 2009. Other related legislations include Environmental Management Act No. 20 of year 2004 Forest Policy and Forest Act No. 14 of year 2002 and Water Supply Act No.12 of year 2009 among others. However the mechanisms processes and institutions through which all stakeholders articulate their priorities exercise their legal rights meet their obligations and mediate their differences is still missing. This study employed descriptive exploratory research design. Data collection was done by the use of both structured and semi structured interview to respondents who were both purpose and simple randomly selected observation and focus group discussion. Review of reports from Districts and Basin offices and internet to access relevant secondary information was done. Results show that WUAs LGAs and WSSAs lack relevant understanding capacities management and law enforcement as result water management generally remains non participatory inefficient and expensive and increased water user conflicts in Kisangata and Ilonga WUAs of Mkondoa sub catchment Morogoro region. The study propose participatory approaches best practices on water resource management at local level for embracement of Community- Based Water Resource Management as the only option of managing sub catchment water resources and reduce water related conflicts among water users. Awareness creation on policy and establishment of alternative economic activities like horticulture bee keeping and poultry is significant to give relief to land.

Evidence for responses in water chemistry and macroinvertebrates in a strongly acidified mountain stream

Czech Academy of Sciences Publication Activity Database

Beneš, F.; Horecký, J.; Senoo, T.; Kamasová, L.; Lamačová, Anna; Tátosová, J.; Hardekopf, D. W.; Stuchlík, Evžen

2017-01-01

Roč. 72, č. 9 (2017), s. 1049-1058 ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA17-05935S; GA ČR(CZ) GA15-08124S Institutional support: RVO:86652079 ; RVO:60077344 Keywords : acidified mountain stream * macroinvertebrates * logging * hydrological patterns * recovery Subject RIV: EH - Ecology, Behaviour; EH - Ecology, Behaviour (BC-A) OBOR OECD: Environmental sciences (social aspects to be 5.7); Environmental sciences (social aspects to be 5.7) (BC-A) Impact factor: 0.759, year: 2016

THE HYDROLOGIC RESPONSE OF A SMALL CATCHMENT TO CLEAR-CUTTING

Science.gov (United States)

We simulated how a landscape disturbance (e.g., fire or clear-cutting) alters hillslope and catchment hydrologic processes. Specifically, we simulated how the pattern and magnitude of tree removal in a catchment increases downslope transport of water and alters catchment soil moi...

A distributed water level network in ephemeral river reaches to identify hydrological processes within anthropogenic catchments

Science.gov (United States)

Sarrazin, B.; Braud, I.; Lagouy, M.; Bailly, J. S.; Puech, C.; Ayroles, H.

2009-04-01

In order to study the impact of land use change on the water cycle, distributed hydrological models are more and more used, because they have the ability to take into account the land surface heterogeneity and its evolution due to anthropogenic pressure. These models provide continuous distributed simulations of streamflow, runoff, soil moisture, etc, which, ideally, should be evaluated against continuous distributed measurements, taken at various scales and located in nested sub-catchments. Distributed network of streamflow gauging stations are in general scarce and very expensive to maintain. Furthermore, they can hardly be installed in the upstream parts of the catchments where river beds are not well defined. In this paper, we present an alternative to these standard streamflow gauging stations network, based on self powered high resolution water level sensors using a capacitive water height data logger. One of their advantages is that they can be installed even in ephemeral reaches and from channel head locations to high order streams. Furthermore, these innovative and easily adaptable low cost sensors offer the possibility to develop in the near future, a wireless network application. Such a network, including 15 sensors has been set up on nested watersheds in small and intermittent streams of a 7 km² catchment, located in the mountainous "Mont du Lyonnais" area, close to the city of Lyon, France. The land use of this catchment is mostly pasture, crop and forest, but the catchment is significantly affected by human activities, through the existence of a dense roads and paths network and urbanized areas. The equipment provides water levels survey during precipitation events in the hydrological network with a very accurate time step (2 min). Water levels can be related to runoff production and catchment response as a function of scale. This response will depend, amongst other, on variable soil water storage capacity, physiographic data and characteristics of

Influence of land use changes on soil carbon stock and soil carbon erosion in a Mediterranean catchment

Energy Technology Data Exchange (ETDEWEB)

Boix-Fayos, C.; Martinez-Mena, M.; Vente, J. de; Albaladejo, J.

2009-07-01

The effect of changing land uses on the organic soil carbon (C) stock and the soil C transported by water erosion and buried in depositions wedges behring check-dams was estimated in a Mediterranean catchment in SE Spin. the 57% decrease in agricultural areas and 1.5-fold increase of the total forest cover between 1956 and 1997 induced an accumulation rate of total organic carbon (TOC) in the soil of 10.73 g m{sup -}2 yr{sup -}1. The mineral-associated organic carbon (MOC) represented the 70% of the soil carbon pool, the particulate organic carbon (POC) represented a 30% of the soil carbon pool. The average sediments/soil enrichment ratio at the sub catchment scale (8-125 ha) was 0.59{+-}0.43 g kg{sup -}1. Eroded soil C accounted for between 2% to 78% of the soil c stock in the first 5 cm of the soil in the subcatchments. the C erosion rate varied between 0.008 and 0.2 t ha{sup -}1 yr{sup -}1. (Author) 20 refs.

Influence of land use changes on soil carbon stock and soil carbon erosion in a Mediterranean catchment

International Nuclear Information System (INIS)

Boix-Fayos, C.; Martinez-Mena, M.; Vente, J. de; Albaladejo, J.

2009-01-01

The effect of changing land uses on the organic soil carbon (C) stock and the soil C transported by water erosion and buried in depositions wedges behring check-dams was estimated in a Mediterranean catchment in SE Spin. the 57% decrease in agricultural areas and 1.5-fold increase of the total forest cover between 1956 and 1997 induced an accumulation rate of total organic carbon (TOC) in the soil of 10.73 g m - 2 yr - 1. The mineral-associated organic carbon (MOC) represented the 70% of the soil carbon pool, the particulate organic carbon (POC) represented a 30% of the soil carbon pool. The average sediments/soil enrichment ratio at the sub catchment scale (8-125 ha) was 0.59±0.43 g kg - 1. Eroded soil C accounted for between 2% to 78% of the soil c stock in the first 5 cm of the soil in the subcatchments. the C erosion rate varied between 0.008 and 0.2 t ha - 1 yr - 1. (Author) 20 refs.

Advancing Land-Sea Conservation Planning: Integrating Modelling of Catchments, Land-Use Change, and River Plumes to Prioritise Catchment Management and Protection

Science.gov (United States)

Álvarez-Romero, Jorge G.; Pressey, Robert L.; Ban, Natalie C.; Brodie, Jon

2015-01-01

Human-induced changes to river loads of nutrients and sediments pose a significant threat to marine ecosystems. Ongoing land-use change can further increase these loads, and amplify the impacts of land-based threats on vulnerable marine ecosystems. Consequently, there is a need to assess these threats and prioritise actions to mitigate their impacts. A key question regarding prioritisation is whether actions in catchments to maintain coastal-marine water quality can be spatially congruent with actions for other management objectives, such as conserving terrestrial biodiversity. In selected catchments draining into the Gulf of California, Mexico, we employed Land Change Modeller to assess the vulnerability of areas with native vegetation to conversion into crops, pasture, and urban areas. We then used SedNet, a catchment modelling tool, to map the sources and estimate pollutant loads delivered to the Gulf by these catchments. Following these analyses, we used modelled river plumes to identify marine areas likely influenced by land-based pollutants. Finally, we prioritised areas for catchment management based on objectives for conservation of terrestrial biodiversity and objectives for water quality that recognised links between pollutant sources and affected marine areas. Our objectives for coastal-marine water quality were to reduce sediment and nutrient discharges from anthropic areas, and minimise future increases in coastal sedimentation and eutrophication. Our objectives for protection of terrestrial biodiversity covered species of vertebrates. We used Marxan, a conservation planning tool, to prioritise interventions and explore spatial differences in priorities for both objectives. Notable differences in the distributions of land values for terrestrial biodiversity and coastal-marine water quality indicated the likely need for trade-offs between catchment management objectives. However, there were priority areas that contributed to both sets of objectives. Our

Advancing Land-Sea Conservation Planning: Integrating Modelling of Catchments, Land-Use Change, and River Plumes to Prioritise Catchment Management and Protection.

Directory of Open Access Journals (Sweden)

Jorge G Álvarez-Romero

Full Text Available Human-induced changes to river loads of nutrients and sediments pose a significant threat to marine ecosystems. Ongoing land-use change can further increase these loads, and amplify the impacts of land-based threats on vulnerable marine ecosystems. Consequently, there is a need to assess these threats and prioritise actions to mitigate their impacts. A key question regarding prioritisation is whether actions in catchments to maintain coastal-marine water quality can be spatially congruent with actions for other management objectives, such as conserving terrestrial biodiversity. In selected catchments draining into the Gulf of California, Mexico, we employed Land Change Modeller to assess the vulnerability of areas with native vegetation to conversion into crops, pasture, and urban areas. We then used SedNet, a catchment modelling tool, to map the sources and estimate pollutant loads delivered to the Gulf by these catchments. Following these analyses, we used modelled river plumes to identify marine areas likely influenced by land-based pollutants. Finally, we prioritised areas for catchment management based on objectives for conservation of terrestrial biodiversity and objectives for water quality that recognised links between pollutant sources and affected marine areas. Our objectives for coastal-marine water quality were to reduce sediment and nutrient discharges from anthropic areas, and minimise future increases in coastal sedimentation and eutrophication. Our objectives for protection of terrestrial biodiversity covered species of vertebrates. We used Marxan, a conservation planning tool, to prioritise interventions and explore spatial differences in priorities for both objectives. Notable differences in the distributions of land values for terrestrial biodiversity and coastal-marine water quality indicated the likely need for trade-offs between catchment management objectives. However, there were priority areas that contributed to both

Representing macropore flow at the catchment scale: a comparative modeling study

Science.gov (United States)

Liu, D.; Li, H. Y.; Tian, F.; Leung, L. R.

2017-12-01

Macropore flow is an important hydrological process that generally enhances the soil infiltration capacity and velocity of subsurface water. Up till now, macropore flow is mostly simulated with high-resolution models. One possible drawback of this modeling approach is the difficulty to effectively represent the overall typology and connectivity of the macropore networks. We hypothesize that modeling macropore flow directly at the catchment scale may be complementary to the existing modeling strategy and offer some new insights. Tsinghua Representative Elementary Watershed model (THREW model) is a semi-distributed hydrology model, where the fundamental building blocks are representative elementary watersheds (REW) linked by the river channel network. In THREW, all the hydrological processes are described with constitutive relationships established directly at the REW level, i.e., catchment scale. In this study, the constitutive relationship of macropore flow drainage is established as part of THREW. The enhanced THREW model is then applied at two catchments with deep soils but distinct climates, the humid Asu catchment in the Amazon River basin, and the arid Wei catchment in the Yellow River basin. The Asu catchment has an area of 12.43km2 with mean annual precipitation of 2442mm. The larger Wei catchment has an area of 24800km2 but with mean annual precipitation of only 512mm. The rainfall-runoff processes are simulated at a hourly time step from 2002 to 2005 in the Asu catchment and from 2001 to 2012 in the Wei catchment. The role of macropore flow on the catchment hydrology will be analyzed comparatively over the Asu and Wei catchments against the observed streamflow, evapotranspiration and other auxiliary data.

Modeling the Effects of Drought Events on Forest Ecosystem Functioning Historically and Under Scenarios of Climate Change

Science.gov (United States)

Ren, J.; Hanan, E. J.; Kolden, C.; Abatzoglou, J. T.; Tague, C.; Liu, M.; Adam, J. C.

2017-12-01

Drought events have been increasing across the western United States in recent years. Many studies have shown that, in the context of climate change, droughts will continue to be stronger, more frequent, and prolonged in the future. However, the response of forest ecosystems to droughts, particularly multi-year droughts, is not well understood. The objectives of this study are to examine how drought events of varying characteristics (e.g. intensity, duration, frequency, etc.) have affected the functioning of forest ecosystems historically, and how changing drought characteristics (including multi-year droughts) may affect forest functioning in a future climate. We utilize the Regional Hydro-Ecological Simulation System (RHESSys) to simulate impacts of both historical droughts and scenarios of future droughts on forest ecosystems. RHESSys is a spatially-distributed and process-based model that captures the interactions between coupled biogeochemical and hydrologic cycles at catchment scales. Here our case study is the Trail Creek catchment of the Big Wood River basin in Idaho, the Northwestern USA. For historical simulations, we use the gridded meteorological data of 1979 to 2016; for future climate scenarios, we utilize downscaled data from GCMs that have been demonstrated to capture drought events in the Northwest of the USA. From these climate projections, we identify various types of drought in intensity and duration, including multi-year drought events. We evaluate the following responses of ecosystems to these events: 1) evapotranspiration and streamflow; 2) gross primary productivity; 3) the post-drought recovery of plant biomass; and 4) the forest functioning and recovery after multi-year droughts. This research is part of an integration project to examine the roles of drought, insect outbreak, and forest management activities on wildfire activity and its impacts. This project will provide improved information for forest managers and communities in the wild

Factors of influencing dissolved organic carbon stabilization in two cambic forest soils with contrasting soil-forming processes

Science.gov (United States)

Kawasaki, M.; Ohte, N.; Asano, Y.; Uchida, T.; Kabeya, N.; Kim, S.

2004-05-01

Stabilization of Dissolved Organic Carbon (DOC) in forest soil is a major process of soil organic carbon formation. However, the factors influencing DOC stabilization are poorly understood. To clarify the factors that affect the stabilization of DOC in forest soil mantle, we measured DOC concentrations and soil properties which were DOC adsorption efficiency at two adjacent cambic forest soils with contrasting forest management histories in Tanakami Mountains, central Japan. Matsuzawa was devastated about 1,200 years ago by excessive timber use and remained denuded for a long period. Hillside restoration and reforestation work have been carried out over the last 100 years and soil loss has been reduced. Fudoji is covered with undisturbed forest (mixed stands of cypress and oaks) with developed forest soils (more than 2,600 years old). There was no apparent seasonal variation in DOC concentration in the soil solution in either catchment. In addition, there were no significant relationships between the DOC concentration, soil temperature, and new water ratio. These results indicate that temporal variation in biological activity and rainfall-runoff process have little effect on temporal variation in DOC. The vertical variation in the DOC adsorption efficiency and DOC concentration differed between Matsuzawa and Fudoji, and the highest DOC removal rate occurred at the lowest DOC adsorption efficiency in the 0 to 10-cm soil layer at Fudoji. These results suggest that DOC removal rate is independent of DOC adsorption efficiency. Below 60 cm soil depth, DOC fluxes were constant and dissolved organic Al concentrations were little or zero in either catchment. These results suggest that abiotic precipitation of DOC is a major mechanism for stabilization of DOC. Therefore, DOC content which is able to form metal complexes may be the most important factor of influencing DOC stabilization in cambic forest soil.

LBA-ECO ND-11 Soil Properties of Forested Headwater Catchments, Mato Grosso, Brazil

Data.gov (United States)

National Aeronautics and Space Administration — The results of the analysis of soil chemical parameters, texture, and color are reported for 185 georeferenced soil profile sample points over four forested...

The Vaal river catchment: Problems and research needs

CSIR Research Space (South Africa)

Braune, E

1987-01-01

Full Text Available The vaal river catchments contains South African's economic heartland, the Pretoria -Witwatersrand-Vereeniging (PWV) complex. Although the catchments only produces eight per cent of the mean annual runoff of the country it has highest concentration...

Hydrological impacts of land use change in three diverse South African catchments

Science.gov (United States)

Warburton, Michele L.; Schulze, Roland E.; Jewitt, Graham P. W.

2012-01-01

SummaryIn order to meet society's needs for water, food, fuel and fibre, the earth's natural land cover and land use have been significantly changed. These changes have impacted on the hydrological responses and thus available water resources, as the hydrological responses of a catchment are dependent upon, and sensitive to, changes in the land use. The degree of anthropogenic modification of the land cover, the intensity of the land use changes and location of land uses within a catchment determines the extent to which land uses influences hydrological response of a catchment. The objective of the study was to improve understanding of the complex interactions between hydrological response and land use to aid in water resources planning. To achieve this, a hydrological model, viz. the ACRU agrohydrological model, which adequately represents hydrological processes and is sensitive to land use changes, was used to generate hydrological responses from three diverse, complex and operational South African catchments under both current land use and a baseline land cover. The selected catchments vary with respect to both land use and climate. The semi-arid sub-tropical Luvuvhu catchment has a large proportion of subsistence agriculture and informal residential areas, whereas in the winter rainfall Upper Breede catchment the primary land uses are commercial orchards and vineyards. The sub-humid Mgeni catchment is dominated by commercial plantation forestry in the upper reaches, commercial sugarcane and urban areas in the middle reaches, with the lower reaches dominated by urban areas. The hydrological responses of the selected catchments to land use change were complex. Results showed that the contributions of different land uses to the streamflow generated from a catchment is not proportional to the relative area of that land use, and the relative contribution of the land use to the catchment streamflow varies with the mean annual rainfall of the catchment. Furthermore

Predictive mapping of the acidifying potential for acid sulfate soils

DEFF Research Database (Denmark)

Boman, A; Beucher, Amélie; Mattbäck, S

Developing methods for the predictive mapping of the potential environmental impact from acid sulfate soils is important because recent studies (e.g. Mattbäck et al., under revision) have shown that the environmental hazards (e.g. leaching of acidity) related to acid sulfate soils vary depending...... on their texture (clay, silt, sand etc.). Moreover, acidity correlates, not only with the sulfur content, but also with the electrical conductivity (EC) measured after incubation. Electromagnetic induction (EMI) data collected from an EM38 proximal sensor also enabled the detailed mapping of acid sulfate soils...... over a field (Huang et al., 2014).This study aims at assessing the use of EMI data for the predictive mapping of the acidifying potential in an acid sulfate soil area in western Finland. Different supervised classification modelling techniques, such as Artificial Neural Networks (Beucher et al., 2015...

Pesticide modelling for a small catchment using SWAT-2000.

Science.gov (United States)

Kannan, Narayanan; White, Sue M; Worrall, Fred; Whelan, Mick J

2006-01-01

Pesticides in stream flow from the 142 ha Colworth catchment in Bedfordshire, UK were monitored from October 1999 to December 2000. About 47% of the catchment is tile-drained and different pesticides and cropping patterns have recently been evaluated in terms of their effect on nutrient and pesticide losses to the stream. The data from Colworth were used to test soil and water assessment tool (SWAT) 2000 predictions of pesticide concentrations at the catchment outlet. A sound model set-up to carry out pesticide modelling was created by means of hydrological modelling with proper simulation of crop growth and evapotranspiration. The pesticides terbuthylazine, terbutryn, cyanazine and bentazone were modelled. There was close agreement between SWAT-predicted pesticide concentration values and observations. Scenario trials were conducted to explore management options for reducing pesticide loads arriving at the catchment outlet. The results obtained indicate that SWAT can be used as a tool to understand pesticide behavior at the catchment scale.

Hydrological effects of fire in South-African mountain catchments

CSIR Research Space (South Africa)

Scott, DF

1993-10-01

Full Text Available is entirely suppressed and a deep litter mat develops giving a continuous cover with good soil protection characteristics. The timber plantations are at risk of burning as they are surrounded by fire-maintained vegetation... in vegetation type and fire characteristics. Description of the research catchments and treatments The catchments studied are all small, mountainous and with a high rainfall, each forming part of long-term experimental catchment...

Hydrologic landscape regionalisation using deductive classification and random forests.

Directory of Open Access Journals (Sweden)

Stuart C Brown

Full Text Available Landscape classification and hydrological regionalisation studies are being increasingly used in ecohydrology to aid in the management and research of aquatic resources. We present a methodology for classifying hydrologic landscapes based on spatial environmental variables by employing non-parametric statistics and hybrid image classification. Our approach differed from previous classifications which have required the use of an a priori spatial unit (e.g. a catchment which necessarily results in the loss of variability that is known to exist within those units. The use of a simple statistical approach to identify an appropriate number of classes eliminated the need for large amounts of post-hoc testing with different number of groups, or the selection and justification of an arbitrary number. Using statistical clustering, we identified 23 distinct groups within our training dataset. The use of a hybrid classification employing random forests extended this statistical clustering to an area of approximately 228,000 km2 of south-eastern Australia without the need to rely on catchments, landscape units or stream sections. This extension resulted in a highly accurate regionalisation at both 30-m and 2.5-km resolution, and a less-accurate 10-km classification that would be more appropriate for use at a continental scale. A smaller case study, of an area covering 27,000 km2, demonstrated that the method preserved the intra- and inter-catchment variability that is known to exist in local hydrology, based on previous research. Preliminary analysis linking the regionalisation to streamflow indices is promising suggesting that the method could be used to predict streamflow behaviour in ungauged catchments. Our work therefore simplifies current classification frameworks that are becoming more popular in ecohydrology, while better retaining small-scale variability in hydrology, thus enabling future attempts to explain and visualise broad-scale hydrologic

The relative influence of climate and catchment properties on hydrological drought

Science.gov (United States)

Van Loon, Anne; Laaha, Gregor; Koffler, Daniel

2014-05-01

Studying hydrological drought (a below-normal water availability in groundwater, lakes and streams) is important to society and the ecosystem, but can also reveal interesting information about catchment functioning. This information can later be used for predicting drought in ungauged basins and to inform water management decisions. In this study, we used an extensive Austrian dataset of discharge measurements in clusters of catchments and combine this dataset with thematic information on climate and catchment properties. Our aim was to study the relative effects of climate and catchment characteristics on drought duration and deficit and on hydrological drought typology. Because the climate of the region is roughly uniform, our hypothesis was that the effect of differences of catchment properties would stand out. From time series of precipitation and discharge we identified droughts with the widely-used threshold level approach, defining a drought when a variable falls below a pre-defined threshold representing the regime. Drought characteristics that were analysed are drought duration and deficit. We also applied the typology of Van Loon & Van Lanen (2012). To explain differences in drought characteristics between catchments we did a correlation analysis with climate and catchment characteristics, based on Pearson correlation. We found very interesting patterns in the correlations of drought characteristics with climate and catchment properties: 1) Droughts with long duration (mean and maximum) and composite droughts are related to catchments with a high BFI (high baseflow) and a high percentage of shallow groundwater tables. 2) The deficit (mean and maximum) of both meteorological droughts and hydrological droughts is strongly related to catchment humidity, in this case quantified by average annual precipitation. 3) The hydrological drought types that are related to snow, i.e. cold snow season drought and snow melt drought, occur in catchments that are have a

Participatory catchment management: an opportunity for South Africa

CSIR Research Space (South Africa)

Versfeld, DB

1995-01-01

Full Text Available offer a new opportunity for communities living within these catchments to share their knowledge and to become involved in planning and implementing the management process. This paper discusses the use of Participatory Rural Appraisal (PRA) in a catchment...

Physically-Based Modelling of the Post-Fire Runoff Response of a Forest Catchment in Central Portugal

NARCIS (Netherlands)

Eck, Van Christel M.; Nunes, Joao P.; Vieira, Diana C.S.; Keesstra, Saskia; Keizer, Jan Jacob

2016-01-01

Forest fires are a recurrent phenomenon in Mediterranean forests, with impacts for human landscapes and communities, which must be understood before they can be managed. This study used the physically based Limburg Soil Erosion Model (LISEM) to simulate rainfall–runoff response, under soil water

Mercury speciation, fluxes, and fate in the volcanically acidified fluids of Copahue volcano, Argentina

Science.gov (United States)

Kading, T.; Varekamp, J. C.; Andersson, M.; Balcom, P.; Mason, R. P.

2010-12-01

The behavior of mercury in volcanic acid springs and acidified rivers is poorly known, despite the potential impact this vector of contamination has on local surface and ground water quality. Mercury was measured in a volcanically acidified river system (pHvolcano, determined from river water flux measurements and Hg concentrations, was modest and varied between the 3/2008 and 3/2009 sampling campaigns resp. from 0.7 to 1.1 moles/year. The Hg:S ratio of the acid fluids was ~10-8, several orders of magnitude lower than that typically found in volcanic plumes and fumaroles. The small Hg flux and low Hg:S values suggest that the system is either inherently Hg-poor or has lost Hg through vapor loss deeper in the hydrothermal system. Support for the latter comes from high Hg concentrations in geothermal vents and mudpots on the flank of the mountain (24 - 55 ppm Hg). Mercury concentrations decreased conservatively downstream in the river as based on Hg/Cl and Hg/SO4. Non-conservative depletion occurs in the less acidic Lake Caviahue, suggesting that mercury is removed from the water column by sorption to organic matter or other phases. Mercury analyses of a short lake sediment core confirm this (Hg = 0.01 to 0.70 ppm). No evidence was found for preferential uptake of mercury by jarosite, schwertmannite, or goethite, although the latter two phases precipitate in the most distal and Hg-depleted section of the fluvial system.

GIS-based Approaches to Catchment Area Analyses of Mass Transit

DEFF Research Database (Denmark)

Andersen, Jonas Lohmann Elkjær; Landex, Alex

2009-01-01

Catchment area analyses of stops or stations are used to investigate potential number of travelers to public transportation. These analyses are considered a strong decision tool in the planning process of mass transit especially railroads. Catchment area analyses are GIS-based buffer and overlay...... analyses with different approaches depending on the desired level of detail. A simple but straightforward approach to implement is the Circular Buffer Approach where catchment areas are circular. A more detailed approach is the Service Area Approach where catchment areas are determined by a street network...... search to simulate the actual walking distances. A refinement of the Service Area Approach is to implement additional time resistance in the network search to simulate obstacles in the walking environment. This paper reviews and compares the different GIS-based catchment area approaches, their level...

Appraisal of Farm Forestry Department around Tinderet Forest

International Nuclear Information System (INIS)

Nyambati, R.O; Koech, C.K; Muok, G

2007-01-01

Tinderet forest is one of the most important catchment areas of lake victoria. It is the main source of numerous springs, streams, and rivers that flow into the lake. The forest is also an important habitat for wide variety of water plants and animal species. Although the forest is gazetted as a forest reserve, it has undergone different levels of degradation due to over exploitation of timber, posts, firewood, charcoal and honey by the community living next to the forest. Resource from the forest supplement the communities' meagre income from subsistence farming. A survey was conducted in four Divisions (Chichila, Kipkelion, Fort-Tanan and Tinderet) around the forest to evaluate the status of farm forestry development and underlying reasons for encroachment in the forest. The results showed that, 61% of the people around Tinderet forest were settlers, whose duration of settlement is between 30-40 years. Most farmers were involved in various forms of farming (livestock or crop production) but forestry was not reported as a major activity. Clearing for livestock and crop production, timber for construction and firewood are the main causes of vegetation depletion on farms. Upto 60% of the households were not self reliant on wood products mainly timber and firewood and Fort-Tana (78%) and Kipkelion (70%) were the most affected. Forestry extension services were mainly provided by the Ministry of Agriculture and East African Wildlife Society (EAWS) and were found to be poor on the ground. Other issues that hampered forest development are inadequate provision of germplasm (seed and seedlings). There is therefore a need to build the capacity of the community in the farm forestry through establishment of nurseries and provision of adequate extension services. This would contribute to enhancement of self-reliance in wood products and increased income reducing encroachment into the gazetted forest

The long-term water balance (1972–2004 of upland forestry and grassland at Plynlimon, mid-Wales

Directory of Open Access Journals (Sweden)

2007-01-01

Full Text Available This paper reviews research into the hydrological impacts of UK upland forestry and updates the water balance of the Plynlimon research catchments for the period 1972–2004. Comparison of this network of densely instrumented coniferous forest and grassland catchments builds upon previously reported differences in annual evaporation of the two land uses and, most crucially, provides evidence of systematic, age-related, variations in forest evaporation losses over a managed plantation forest cycle. In comparison with the grassland catchment, the additional water use of the 70% forested catchment fell from 250 to 150 mm yr−1 because of increasing forest age; this is equivalent to a decline from 370 mm to 210 mm extra evaporation from a complete forest cover. At present, with up to half of the forest area felled or only recently replanted, the difference in evaporation between the forest and grass catchments is negligible. Knowledge of the period of maximum tree water use may be critically important for the future management of multi-use forests. This is also being investigated by micro-meteorological measurements at the scale of the forest stand using eddy covariance, in conjunction with the long-term catchment monitoring.

Rice agriculture impacts catchment hydrographic patterns and nitrogen export characteristics in subtropical central China: a paired-catchment study.

Science.gov (United States)

Wang, Yi; Liu, Xinliang; Wang, Hua; Li, Yong; Li, Yuyuan; Liu, Feng; Xiao, Runlin; Shen, Jianlin; Wu, Jinshui

2017-06-01

Increased nitrogen (N) concentrations in water bodies have highlighted issues regarding nutrient pollution in agricultural catchments. In this study, the ammonium-N (NH 4 + -N), nitrate-N (NO 3 - -N), and total N (TN) concentrations were observed in the stream water and groundwater of two contrasting catchments (named Tuojia and Jianshan) in subtropical central China from 2010 to 2014, to determine the rice agriculture impacts on the hydrographic patterns, and N export characteristics of the catchments. The results suggested that greater amounts of stream flow (523.0 vs. 434.7 mm year -1 ) and base flow (237.6 vs. 142.8 mm year -1 ) were produced in Tuojia than in Jianshan, and a greater base flow contribution to stream flow and higher frequencies of high-base flow days were observed during the fallow season than during the rice-growing season, indicating that intensive rice agriculture strongly influences the catchment hydrographic pattern. Rice agriculture resulted in moderate N pollution in the stream water and groundwater, particularly in Tuojia. Primarily, rice agriculture increased the NH 4 + -N concentration in the stream water; however, it increased the NO 3 - -N concentrations in the groundwater, suggesting that the different N species in the paddy fields migrated out of the catchments through distinct hydrological pathways. The average TN loading via stream flow and base flow was greater in Tuojia than in Jianshan (1.72 and 0.58 vs. 0.72 and 0.15 kg N ha -1  month -1 , respectively). Greater TN loading via stream flow was observed during the fallow season in Tuojia and during the rice-growing season in Jianshan, and these different results were most likely a result of the higher base flow contribution to TN loading (33.5 vs. 21.3%) and greater base flow enrichment ratio (1.062 vs. 0.876) in Tuojia than in Jianshan. Therefore, the impact of rice agriculture on catchment eco-hydrological processes should be considered when performing water quality

Acidifier application rate impacts on ammonia emissions from US roaster chicken houses

Science.gov (United States)

Shah, Sanjay B.; Grimes, Jesse L.; Oviedo-Rondón, Edgar O.; Westerman, Philip W.

2014-08-01

Due to its potential environmental and public health impacts, emissions of ammonia (NH3) as well as several other gases from US livestock farms may be regulated. Broiler houses are important sources of NH3 emissions. However, there are no emissions data from roaster (8-12 wk old broilers, ˜4 kg ea.) houses. Producers treat the litter in broiler houses with acidifiers, such as sodium bisulfate (SBS, NaHSO4) to reduce ammonia production and protect bird health. However, there is very little data on the effect of acidifiers, particularly at high application rates on ammonia emissions. The impact of different SBS application rates [High (0.95-1.46 kg m-2, whole house), Medium (0.73 kg m-2, whole house), Low (0.37-0.49 kg m-2, whole house), and Control (0.37-0.49 kg m-2, brood chamber)] on ammonia emissions was evaluated in commercial roaster houses over 22 months spanning eight flocks. Ammonia emission from each fan was measured with an acid scrubber that operated only when the fan operated. Emissions were calculated using >95% measured data with the rest being estimated using robust methods. Exhaust ammonia-N concentrations were inversely correlated with the SBS application rates. Emission rates on animal unit (AU, where 1 AU = 500 kg live-mass) basis (ER, g d-1 AU-1) were reduced by 27, 13, and 5%, respectively, in the High, Medium, and Low treatments vs. the Control treatment (mean: 100 g d-1 AU-1, range: 86-114 g d-1 AU-1). Emission rates for the Control treatment measured in this study on roasters were mostly higher than ERs in the literature. Differences in ERs are not only due to diet, environmental and management conditions, but also due to measurement methods.

Reliance on shallow soil water in a mixed-hardwood forest in central Pennsylvania

Science.gov (United States)

Katie P. Gaines; Jane W. Stanley; Frederick C. Meinzer; Katherine A. McCulloh; David R. Woodruff; Weile Chen; Thomas S. Adams; Henry Lin; David M. Eissenstat; Nathan Phillips

2015-01-01

We investigated depth of water uptake of trees on shale-derived soils in order to assess the importance of roots over a meter deep as a driver of water use in a central Pennsylvania catchment. This information is not only needed to improve basic understanding of water use in these forests but also to improve descriptions of root function at depth in hydrologic process...

The long-term hydrological effect of forest stands on the stability of slopes

Science.gov (United States)

Bogaard, T. A.; Meng, W.; van Beek, L. P. H.

2012-04-01

Forest is widely known to improve slope stability as a result of mechanical and hydrological effects. While the mechanics underlying the stabilizing process of root reinforcement are well understood and quantified, the influence of forest on the occurrence of critical hydrological conditions in terms of suction or pore pressure remains uncertain. Due to seasonal and inter-annual fluctuations, the stabilizing influence of evaporation and transpiration is difficult to isolate from the overall noise of the hydrological signal. More long-term effects of forest stands on soil development are highly variable and thus difficult to observe and quantify. Often these effects are ambivalent, having potentially a stabilizing or destabilizing influence on a slope under particular conditions (e.g., more structured soils leading to both rapid infiltration and drainage). Consequently, it can be postulated that forests will hydrologically influence the magnitude-frequency distribution of landsliding, not only at the stand level but also on a regional scale through the groundwater system. The overall aim of this research is to understand and quantify the stabilizing hydrological effect of forests on potentially unstable slopes. To this end, we focus on the changes in the magnitude-frequency distribution of landsliding that arise as a result of variations in evapotranspiration losses over the life cycle of stands. Temporal variations in evapotranspiration comprise first of all the interception that can account for an important amount of evaporation from a forest, and that changes with seasonal and annual variations in the interception capacity of the canopy and forest floor. Transpiration also represents an important loss that varies over the various growth stages of a forest stand. Based on a literature review of water consumption by tree species and water balance studies of forested catchments we defined the potential transpiration for different growth stages. This information we

Side-band injection of acidified cattle slurry as starter P-fertilization for maize seedlings

DEFF Research Database (Denmark)

Petersen, Jens; Lemming, Camilla; Rubæk, Gitte Holton

Accumulation of phosphorus (P) in agricultural soils has caused increasing environmental concerns. Maize cropped for fodder implies return of animal manures rich in nutrients. In addition, starter fertilization with mineral P is used in cold conditions for maize cropping. It was hypothesized...... that the use of the additional mineral P could be excluded by increased availability of the P applied by animal manures. In a growth chamber experiment we investigated the effect of acidified slurry on the growth and nutrient uptake in maize seedlings. In special designed pot the slurries and mineral reference...

Eubiotic effect of a dietary acidifier (potassium diformate) on the health status of cultured Oreochromis niloticus

Science.gov (United States)

Abu Elala, Nermeen M.; Ragaa, Naela M.

2014-01-01

In connection with the global demand for safe human food and the production of environmentally friendly aquaculture products, acidifiers are natural organic acids and salts that have received considerable attention as animal-feed additives. The current study was designed to evaluate the effects of potassium diformate (KDF) on the growth performance and immunity of cultured Oreochromis niloticus (O. niloticus). Four iso-nitrogenous and iso-caloric rations containing graded levels of KDF, including 0% (control basal diet), 0.1%, 0.2% and 0.3%, were fed separately to four equal fish groups (30 fish/group with an initial body weight of 53.49 ± 6.15 g) for sixty days. At the end of the experimental period, the fish groups fed on 0.2% and 0.3% KDF exhibited significant improvements in their feed intake, live weight gain, specific growth rate, feed conversion ratio and protein efficiency ratio, with concomitant improvement of their apparent protein digestibility (p fish groups fed on KDF and challenged orally with Aeromonas hydrophila was lower than that of the control group. The resistance against diseases increased with dietary KDF in a dose-dependent manner. Thus, we conclude that the use of acidifiers can be an efficient tool to achieve sustainable, economical and safe fish production. PMID:26199753

Three very high resolution optical images for land use mapping of a suburban catchment: input to distributed hydrological models

Science.gov (United States)

Jacqueminet, Christine; Kermadi, Saïda; Michel, Kristell; Jankowfsky, Sonja; Braud, Isabelle; Branger, Flora; Beal, David; Gagnage, Matthieu

2010-05-01

Keywords : land cover mapping, very high resolution, remote sensing processing techniques, object oriented approach, distributed hydrological model, peri-urban area Urbanization and other modifications of land use affect the hydrological cycle of suburban catchments. In order to quantify these impacts, the AVuPUR project (Assessing the Vulnerability of Peri-Urban Rivers) is currently developing a distributed hydrological model that includes anthropogenic features. The case study is the Yzeron catchment (150 km²), located close to Lyon city, France. This catchment experiences a growing of urbanization and a modification of traditional land use since the middle of the 20th century, resulting in an increase of flooding, water pollution and river banks erosion. This contribution discusses the potentials of automated data processing techniques on three different VHR images, in order to produce appropriate and detailed land cover data for the models. Of particular interest is the identification of impermeable surfaces (buildings, roads, and parking places) and permeable surfaces (forest areas, agricultural fields, gardens, trees…) within the catchment, because their infiltration capacity and their impact on runoff generation are different. Three aerial and spatial images were acquired: (1) BD Ortho IGN aerial images, 0.50 m resolution, visible bands, may 5th 2008; (2) QuickBird satellite image, 2.44 m resolution, visible and near-infrared bands, august 29th 2008; (3) Spot satellite image, 2.50 m resolution, visible and near-infrared bands, September 22nd 2008. From these images, we developed three image processing methods: (1) a pixel-based method associated to a segmentation using Matlab®, (2) a pixel-based method using ENVI®, (3) an object-based classification using Definiens®. We extracted six land cover types from the BD Ortho IGN (visible bands) and height classes from the satellite images (visible and near infrared bands). The three classified images are

Nitrogen attenuation along delivery pathways in agricultural catchments

Science.gov (United States)

McAleer, Eoin; Mellander, Per-Erik; Coxon, Catherine; Richards, Karl G.

2014-05-01

Hillslope hydrologic systems and in particular near-stream saturated zones are active sites of nitrogen (N) biogeochemical dynamics. The efficiency of N removal and the ratio of reaction products (nitrous oxide and dinitrogen) in groundwater is highly variable and depends upon aquifer hydrology, mineralogy, dissolved oxygen, energy sources and redox chemistry. There are large uncertainties in the closing of N budgets in agricultural catchments. Spatial and temporal variability in groundwater physico-chemistry, catchment hydrology and land-use gives rise to hotspots and hot moments of N attenuation. In addition the production, consumption and movement of denitrification products remains poorly understood. The focus of this study is to develop a holistic understanding of N dynamics in groundwater as it moves from the top of the hillslope to the stream. This includes saturated groundwater flow, exchange at the groundwater-surface water interface and hyporheic zone flow. This project is being undertaken in two ca. 10km2 Irish catchments, characterised by permeable soils. One catchment is dominated by arable land overlying slate bedrock and the other by grassland overlying sandstone. Multi-level monitoring wells have been installed at the upslope, midslope and bottom of each hillslope. The piezometers are screened to intercept the subsoil, weathered bedrock and competent bedrock zones. Groundwater samples for nitrate (NO3-N) nitrite (NO2-N), ammonium (NH4-N) and total nitrogen are collected on a monthly basis while dissolved gas concentrations are collected seasonally. Groundwater NO3-N profiles from monitoring data to date in both catchments differ markedly. Although the two catchments had similar 3 year mean concentrations of 6.89 mg/L (arable) and 6.24 mg/L (grassland), the grassland catchment had higher spatial and temporal variation. The arable catchment showed relatively homogenous NO3-N concentrations in all layers and zones (range: 1.2 - 12.13 mg/L, SD = 1.60 mg

Modelling catchment areas for secondary care providers: a case study.

Science.gov (United States)

Jones, Simon; Wardlaw, Jessica; Crouch, Susan; Carolan, Michelle

2011-09-01

Hospitals need to understand patient flows in an increasingly competitive health economy. New initiatives like Patient Choice and the Darzi Review further increase this demand. Essential to understanding patient flows are demographic and geographic profiles of health care service providers, known as 'catchment areas' and 'catchment populations'. This information helps Primary Care Trusts (PCTs) to review how their populations are accessing services, measure inequalities and commission services; likewise it assists Secondary Care Providers (SCPs) to measure and assess potential gains in market share, redesign services, evaluate admission thresholds and plan financial budgets. Unlike PCTs, SCPs do not operate within fixed geographic boundaries. Traditionally, SCPs have used administrative boundaries or arbitrary drive times to model catchment areas. Neither approach satisfactorily represents current patient flows. Furthermore, these techniques are time-consuming and can be challenging for healthcare managers to exploit. This paper presents three different approaches to define catchment areas, each more detailed than the previous method. The first approach 'First Past the Post' defines catchment areas by allocating a dominant SCP to each Census Output Area (OA). The SCP with the highest proportion of activity within each OA is considered the dominant SCP. The second approach 'Proportional Flow' allocates activity proportionally to each OA. This approach allows for cross-boundary flows to be captured in a catchment area. The third and final approach uses a gravity model to define a catchment area, which incorporates drive or travel time into the analysis. Comparing approaches helps healthcare providers to understand whether using more traditional and simplistic approaches to define catchment areas and populations achieves the same or similar results as complex mathematical modelling. This paper has demonstrated, using a case study of Manchester, that when estimating

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

Leaching of organic carbon and nitrogen from peatland-dominated catchments

International Nuclear Information System (INIS)

Kortelainen, P.

1992-01-01

The area of 13 study catchments is 2.5-56-3 km 2 and 37-87 % of the catchments is covered by peatlands. Ditching intensities varied from 0 to 100 %. Median total organic carbon (TOC) in runoff waters from the catchments was 10-30 mg/l - 1 and median nitrogen (N tot ) 380-1000 μg/1 -1 . The annual leaching of TOC and Ntot was calculated for five catchments for which daily runoff data was available. The range for mean annual leaching of TOC and N tot from the catchments was 4700-7300 kg/km 2 a and 190-250 kg/km -2 a -1 , respectively. The variation between different years was high and annual leaching was closely related to annual runoff. The regional variation in the leaching of TOC and N tot was small compared to the annual variation

Reduction of hexavalent chromium in water samples acidified for preservation

Science.gov (United States)

Stollenwerk, K.G.; Grove, D.B.

1985-01-01

Reduction of hexavalent chromium, Cr(VI), in water samples, preserved by standard techniques, was investigated. The standard preservation technique for water samples that are to be analyzed for Cr(VI) consists of filtration through a 0.45-??m membrane, acidification to a pH plastic bottles. Batch experiments were conducted to evaluate the effect of H+ concentration, NO2, temperature, and dissolved organic carbon (DOC) on the reduction of Cr(VI) to Cr(III). The rate of reduction of Cr(VI) to Cr(III) increased with increasing NO2, DOC, H+, and temperature. Reduction of Cr(VI) by organic matter occurred in some samples even though the samples were unacidified. Reduction of Cr(VI) is inhibited to an extent by storing the sample at 4??C. Stability of Cr(VI) in water is variable and depends on the other constituents present in the sample. Water samples collected for the determination of Cr(VI) should be filtered (0.45-??m membrane), refrigerated, and analyzed as quickly as possible. Water samples should not be acidified. Measurement of total Cr in addition to Cr(VI) can serve as a check for Cr(VI) reduction. If total Cr is greater than Cr(VI), the possibility that Cr(VI) reduction has occurred needs to be considered.The rate of reduction of Cr(VI) to Cr(III) increased with increasing NO//2, DOC, H** plus , and temperature. Reduction of Cr(VI) by organic matter occurred in some samples even though the samples were unacidified. Reduction of Cr(VI) is inhibited to an extent by storing the sample at 4 degree C. Stability of Cr(VI) in water is variable and depends on the other constituents present in the sample. Water samples collected for the determination of Cr(VI) should be filtered (0. 45- mu m membrane), refrigerated, and analyzed as quickly as possible. Water samples should not be acidified. Measurement of total Cr in addition to Cr(VI) can serve as a check for Cr(VI) reduction. If total Cr is greater than Cr(VI), the possibility that Cr(VI) reduction has occurred needs

Assessing soil erosion rates for a large catchment in the Central Highlands of Vietnam using fallout radionuclides

International Nuclear Information System (INIS)

Phan Son Hai; Nguyen Thanh Binh; Nguyen Minh Dao; Nguyen Thi Huong Lan; Nguyen Thi Mui; Le Xuan Thang; Phan Quang Trung; Trinh Cong Tu; Tran Tien Dung

2014-01-01

Fallout radionuclides Be-7 and Cs-137 were applied to assess soil erosion rates for a 270.5 km 2 catchment with a variety of slope (from 0 o to more than 45 o , crops or vegetation (natural forest, artificial forest, perennial crops, annual crops) and a variety of tillage and soil conservation measures. Soil erosion rates were estimated at 90 areas within the catchment. Each sampling area has at least one feature of the slope, rainfall, crops, farming practice different from others. Soil erosion rates in this region depend significantly on the slope, crops and farming techniques. Averaging over crops, soil erosion rates by slopes 0 - 5 o , 5 - 15 o , 15 - 25 o and 25 - 35 o are 5.0, 12.8, 18.9 and 21.3 t.ha -1 .y -1 , respectively. Forest land has the least soil erosion rates, ranging between 0.5 t.ha -1 .y -1 and 14 t.ha -1 .y -1 depending on the slope. Annual crops land has the highest soil erosion rates, ranging between 6 t.ha -1 .y -1 and 42 t.ha -1 .y -1 when slope varies from < 5 o to 32 o . Perennial crop land has soil erosion rates in the range of 5 t.ha -1 .y -1 and 39 t.ha -1 .y -1 . In areas with the same slope, the soil erosion rate is the highest for cashew plantations, lower for mulberry field and the lowest for tea or coffee plantations. Soil erosion has resulted in losing a significant quantity of plant nutrients such as OM, N, P 2 O 5 and K 2 O every year. Generally, lost nutrient quantities due to soil erosion are proportional to erosion rates. Some areas of annual crop land lost a large amount of nutrients every year, up to 1435 kg OM, 79 kg N, 54 kg P 2 O 5 and 36 kg K 2 O. Similarly, perennial crop lands in this region could lost up to 1736 kg OM, 91 kg N, 66 kg P 2 O 5 and 40 kg K 2 O every year. Owing to soil erosion, the catchment has lost about 211200 tons of surface soil per year during last 50 years, corresponding to the rate of 7.8 t.ha -1 .y -1 . This amount of eroded soil was deposited in drainage of the catchment and in reservoirs

Estimating retention potential of headwater catchment using Tritium time series

Science.gov (United States)

Hofmann, Harald; Cartwright, Ian; Morgenstern, Uwe

2018-06-01

Headwater catchments provide substantial streamflow to rivers even during long periods of drought. Documenting the mean transit times (MTT) of stream water in headwater catchments and therefore the retention capacities of these catchments is crucial for water management. This study uses time series of 3H activities in combination with major ion concentrations, stable isotope ratios and radon activities (222Rn) in the Lyrebird Creek catchment in Victoria, Australia to provide a unique insight into the mean transit time distributions and flow systems of this small temperate headwater catchment. At all streamflows, the stream has 3H activities (water in the stream is derived from stores with long transit times. If the water in the catchment can be represented by a single store with a continuum of ages, mean transit times of the stream water range from ∼6 up to 40 years, which indicates the large retention potential for this catchment. Alternatively, variations of 3H activities, stable isotopes and major ions can be explained by mixing between of young recent recharge and older water stored in the catchment. While surface runoff is negligible, the variation in stable isotope ratios, major ion concentrations and radon activities during most of the year is minimal (±12%) and only occurs during major storm events. This suggests that different subsurface water stores are activated during the storm events and that these cease to provide water to the stream within a few days or weeks after storm events. The stores comprise micro and macropore flow in the soils and saprolite as well as the boundary between the saprolite and the fractured bed rock. Hydrograph separations from three major storm events using Tritium, electrical conductivity and selected major ions as well a δ18O suggest a minimum of 50% baseflow at most flow conditions. We demonstrate that headwater catchments can have a significant storage capacity and that the relationship between long-water stores and

Measuring the size of an airport's catchment area

NARCIS (Netherlands)

Lieshout, R.

2012-01-01

Although much empirical research exists on the factors that drive passenger airport choice, not much is known about the related topic of airport catchment area size. This paper presents a novel methodology to assess the size of airport catchment areas and the airport’s market shares therein using a

Detecting the hydrological impacts of forest cover change in tropical mountain areas: need for detrending time series of rainfall and streamflow data.

Science.gov (United States)

Molina, A.; Vanacker, V.; Brisson, E.; Balthazar, V.

2012-04-01

Interactions between human activities and the physical environment have increasingly transformed the hydrological functioning of Andean ecosystems. In these human-modified landscapes, land use/-cover change may have a profound effect on riverine water and sediment fluxes. The hydrological impacts of land use/-cover change are diverse, as changes in vegetation affect the various components of the hydrological cycle including evapotranspiration, infiltration and surface runoff. Quantitative data for tropical mountain regions are scarce, as few long time series on rainfall, water discharge and land use are available. Furthermore, time series of rainfall and streamflow data in tropical mountains are often highly influenced by large inter- and intra-annual variability. In this paper, we analyse the hydrological response to complex forest cover change for a catchment of 280 km2 located in the Ecuadorian Andes. Forest cover change in the Pangor catchment was reconstructed based on airphotos (1963, 1977), LANDSAT TM (1991) and ETM+ data (2001, 2009). From 1963, natural vegetation was converted to agricultural land and pine plantations: forests decreased by a factor 2, and paramo decreased by 20 km2 between 1963 and 2009. For this catchment, there exists an exceptionally long record of rainfall and streamflow data that dates back from the '70s till now, but large variability in hydrometeorological data exists that is partly related to ENSO events. Given the nonstationary and nonlinear character of the ENSO-related changes in rainfall, we used the Hilbert-Huang transformation to detrend the time series of the river flow data from inter- and intra-annual fluctuations in rainfall. After applying adaptive data analysis based on empirical model decomposition techniques, it becomes apparent that the long-term trend in streamflow is different from the long-term trend in rainfall data. While the streamflow data show a long-term decrease in monthly flow, the rainfall data have a

Catchment Storage and Transport on Timescales from Minutes to Millennia

Science.gov (United States)

Kirchner, J. W.

2017-12-01

Landscapes are characterized by preferential flow and pervasive heterogeneity on all scales. They therefore store and transmit water and solutes over a wide spectrum of time scales, with important implications for contaminant transport, weathering rates, and runoff chemistry. Theoretical analyses predict, and syntheses of age tracer data confirm, that waters in aquifers are older - often by orders of magnitude - than in the rivers that flow from them, and that this disconnect between water ages arises from aquifer heterogeneity. Recent theoretical studies also suggest that catchment transit time distributions are nonstationary, reflecting temporal variability in precipitation forcing, structural heterogeneity in catchments themselves, and the nonlinearity of the mechanisms controlling storage and transport in the subsurface. The challenge of empirically estimating these nonstationary transit time distributions in real-world catchments, however, has only begun to be explored. In recent years, long-term isotope time series have been collected in many research catchments, and new technologies have emerged that allow quasi-continuous measurements of isotopes in precipitation and streamflow. These new data streams create new opportunities to study how rainfall becomes streamflow following the onset of precipitation. Here I present novel methods for quantifying the fraction of current rainfall in streamflow across ensembles of precipitation events. Benchmark tests with nonstationary catchment models demonstrate that this approach quantitatively measures the short tail of the transit time distribution for a wide range of catchment response characteristics. In combination with reactive tracer time series, this approach can potentially be extended to measure short-term chemical reaction rates at the catchment scale. Applications using high-frequency tracer time series from several experimental catchments demonstrate the utility of the new approach outlined here.

Vulnerability of European freshwater catchments to climate change.

Science.gov (United States)

Markovic, Danijela; Carrizo, Savrina F; Kärcher, Oskar; Walz, Ariane; David, Jonathan N W

2017-09-01

Climate change is expected to exacerbate the current threats to freshwater ecosystems, yet multifaceted studies on the potential impacts of climate change on freshwater biodiversity at scales that inform management planning are lacking. The aim of this study was to fill this void through the development of a novel framework for assessing climate change vulnerability tailored to freshwater ecosystems. The three dimensions of climate change vulnerability are as follows: (i) exposure to climate change, (ii) sensitivity to altered environmental conditions and (iii) resilience potential. Our vulnerability framework includes 1685 freshwater species of plants, fishes, molluscs, odonates, amphibians, crayfish and turtles alongside key features within and between catchments, such as topography and connectivity. Several methodologies were used to combine these dimensions across a variety of future climate change models and scenarios. The resulting indices were overlaid to assess the vulnerability of European freshwater ecosystems at the catchment scale (18 783 catchments). The Balkan Lakes Ohrid and Prespa and Mediterranean islands emerge as most vulnerable to climate change. For the 2030s, we showed a consensus among the applied methods whereby up to 573 lake and river catchments are highly vulnerable to climate change. The anthropogenic disruption of hydrological habitat connectivity by dams is the major factor reducing climate change resilience. A gap analysis demonstrated that the current European protected area network covers climate change. Priority should be placed on enhancing stakeholder cooperation at the major basin scale towards preventing further degradation of freshwater ecosystems and maintaining connectivity among catchments. The catchments identified as most vulnerable to climate change provide preliminary targets for development of climate change conservation management and mitigation strategies. © 2017 John Wiley & Sons Ltd.

Empirical models based on the universal soil loss equation fail to predict sediment discharges from Chesapeake Bay catchments.

Science.gov (United States)

Boomer, Kathleen B; Weller, Donald E; Jordan, Thomas E

2008-01-01

The Universal Soil Loss Equation (USLE) and its derivatives are widely used for identifying watersheds with a high potential for degrading stream water quality. We compared sediment yields estimated from regional application of the USLE, the automated revised RUSLE2, and five sediment delivery ratio algorithms to measured annual average sediment delivery in 78 catchments of the Chesapeake Bay watershed. We did the same comparisons for another 23 catchments monitored by the USGS. Predictions exceeded observed sediment yields by more than 100% and were highly correlated with USLE erosion predictions (Pearson r range, 0.73-0.92; p USLE estimates (r = 0.87; p USLE model did not change the results. In ranked comparisons between observed and predicted sediment yields, the models failed to identify catchments with higher yields (r range, -0.28-0.00; p > 0.14). In a multiple regression analysis, soil erodibility, log (stream flow), basin shape (topographic relief ratio), the square-root transformed proportion of forest, and occurrence in the Appalachian Plateau province explained 55% of the observed variance in measured suspended sediment loads, but the model performed poorly (r(2) = 0.06) at predicting loads in the 23 USGS watersheds not used in fitting the model. The use of USLE or multiple regression models to predict sediment yields is not advisable despite their present widespread application. Integrated watershed models based on the USLE may also be unsuitable for making management decisions.

Does estuarine health relate to catchment land-cover in the East ...

African Journals Online (AJOL)

Possible links between catchment and buffer zone land-cover class composition and the health of the East Kleinemonde Estuary were explored. There was a relationship between catchment land-cover and estuarine health within all assessed catchment delineations. Natural land-cover was determined to be the best ...

Ecosystem monitoring on dispersion and export dynamics of ¹³⁷Cs deposited on the forested area in Fukushima after the nuclear power stations accident in March 2011

Energy Technology Data Exchange (ETDEWEB)

Ohte, Nobuhito; Endo, Izuki; Iseda, Kohei; Tanoi, Keitaro [University of Tokyo, Bunkyo-ku, Tokyo, 113-8657 (Japan); Murakami, Masashi [Chiba University, Inage-ku, Chiba, 263-8522 (Japan); Ishii, Nobuyoshi [National Institute of Radiological Sciences, Inage-ku, Chiba, 263-8555 (Japan)

2014-07-01

The accident of the Fukushima Daiichi Nuclear Power Stations in March 2011 emitted 1.5x10¹⁷ Bq of ¹³¹I, 1.2x10¹⁶ Bq of ¹³⁷Cs into the surrounding environment. Those radioactive substances including ¹³⁷Cs deposited onto the forest areas of the northeastern region of the Honshu Island, Japan. Forests of these regions are especially important for the people not only for their forest production industry, but also for the source areas of drinking water. The first phase of the governmental survey and investigations showed that major portion of deposited ¹³⁷Cs is trapped on the canopies and litter layers of soil surface. As ¹³⁷Cs is easily adsorbed onto clay minerals in soil, major portion of those can be transported by eroded soils and particulate organic matters through the hydrological pathways. Dissolved ¹³⁷Cs which is relatively free from soil adsorption can be taken up by microbes, algae and plants in soil and aquatic systems. Then, those ¹³⁷Cs are eventually introduced into soil insects, worms, aquatic insects, fishes and birds through the food web. To clarify the mechanisms of dispersion and export of ¹³⁷Cs within and from a forested ecosystem, we started intensive field observations and samplings in a small catchment including forests and farmlands in the area ~50 km distant from the Nuclear Power Station. The study is conducted at the Kami-Oguni River catchment in the northern part of Fukushima Prefecture. Major land uses of the catchment are forests and paddy fields. Expected two major pathways of ¹³⁷Cs diffusion and export are investigated; 1) transportation by water movement with dissolved and particulate or colloidal forms through the hydrological processes, 2) dispersion through the food web including both detritus food chains based upon plant litters and grazing food chains based upon living plant leaves in the forest-stream ecological continuum. The ¹³⁷Cs concentrations of stream waters at several sampling