WorldWideScience

Sample records for catchment area miljoekonsekvenser

  1. 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...... between the Circular Buffer approach and the Service Area approach are illustrated and a comparison between the sizes of the catchment areas is made. The strength of the Service Area approach and the impact on the catchment area when adding additional time resistance to crossing of stairways...... is illustrated by a case example. Furthermore, a case example illustrates how the additional time resistance in stairways affects the catchment area of an underground station compared to a ground-level station. It is also illustrated how catchment area analyses can serve in the planning of stops on a new line...

  2. Examination of catchment areas for public transport

    DEFF Research Database (Denmark)

    Landex, Alex; Hansen, Stephen; Andersen, Jonas Lohmann Elkjær

    2006-01-01

    The paper presents a method to examine the catchment areas for stops in high quality public transport systems based on the street network in the examined area. This is achieved by implementing the Service Area functions from the ArcGIS extension Network Analyst. The method is compared to a more...... simple method using only the Euclidean distance from the examined stop and the paper describes the differences in detail-level of the results. Furthermore, the paper describes how the Service Area method can be used to examine increments in the catchment areas by adding extra entrances to stations...... or by making changes in the street network around the station. The paper also discusses the degree of realism in the used GIS networks and how it can affect the size of the catchment areas. It is concluded that the Service Area method improves the detail-level and accuracy in catchment area analyses...

  3. Assessment of runoff contributing catchment areas in rainfall runoff modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Johansen, C.; Schaarup-Jensen, Kjeld

    2006-01-01

    recommended literature values for residential areas. It is proven by comparing rainfall-runoff measurements from four different residential catchments that the literature values of the hydrological reduction factor are over-estimated for this type of catchment. In addition, different catchment descriptions...... are presented in order to investigate how the hydrological reduction factor depends on the level of detail regarding the catchment description. When applying a total survey of the catchment area, including all possible impervious surfaces, a hydrological reduction factor of approximately 0.5 for residential...

  4. Assessment of Runoff Contributing Catchment Areas in Rainfall Runoff Modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren Liedtke; Johansen, C.; Schaarup-Jensen, Kjeld

    2005-01-01

    recommended literary values for residential areas. It is proven by comparing rainfall-runoff measurements from four different residential catchments that the literary values of the hydrological reduction factor are over-estimated for this type of catchments. In addition, different catchment descriptions...... are presented in order to investigate how the hydrological reduction factor depends on the level of detail regarding the catchment description. When applying a total survey of the catchment area, including all possible impervious surfaces, a hydrological reduction factor of approximately 0.5 for residential...

  5. Variable catchment sizes for the two-step floating catchment area (2SFCA) method.

    Science.gov (United States)

    Luo, Wei; Whippo, Tara

    2012-07-01

    Government efforts designed to help improve healthcare access rely on accurate measures of accessibility so that resources can be allocated to truly needy areas. In order to capture the interaction between physicians and populations, various access measures have been utilized, including the popular two-step floating catchment area (2SFCA) method. However, despite the many advantages of 2SFCA, the problems associated with using fixed catchment sizes have not been satisfactorily addressed. We propose a new method to dynamically determine physician and population catchment sizes by incrementally increasing the catchment until a base population and a physician-to-population ratio are met. Preliminary application to the ten-county region in northern Illinois has demonstrated that the new method is effective in determining the appropriate catchment sizes across the urban to suburban/rural continuum and has revealed greater detail in spatial variation of accessibility compared to results using fixed catchment sizes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. 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

  7. Seasonal rainfall predictability over the Lake Kariba catchment area

    CSIR Research Space (South Africa)

    Muchuru, S

    2014-07-01

    Full Text Available are a significant aspect of the catchment. To determine the predictability of seasonal rainfall totals over the Lake Kariba catchment area, this study used the low-level atmospheric circulation (850 hPa geopotential height fields) of a coupled ocean...

  8. A detailed study on Catchment delineation for Urban areas

    Science.gov (United States)

    Sharma, B.; B M, A.; Lohani, B.; Jain, A.

    2015-12-01

    Urban flood modelling is carried out for predicting, analysing and planning of floods in urban areas. Catchment information is an important input for urban flood modelling. Automatic catchment delineation at gully gratings for urban areas using appropriate software packages/methods along with an appropriate set of input data and parameters is still a research challenge. Considering the above, the aim of this study is to (i) identify the best suitable software for automatic catchment delineation by considering gully grating as outlet (ii) understand the effect of resolution of DEM on catchments delineated (iii) understand whether to consider DEM or DSM for catchment delineation (iv) study the effect of grid based and TIN based DEM. In this study catchment delineation has been investigated considering IIT Kanpur as a study site. LiDAR data are used to generate DEM/DSM of the study area. A comparative study of catchment delineation has been carried out between ArcHydro 10.1, BASINS 4.1, ArcSWAT, WMS 7.1, and HEC-GeoHMS approaches. Catchments have been delineated for different drainage threshold areas using gully grating points as outlets and their effects have been compared for the aforementioned software. In order to understand the effect of resolution of data, DEMs of 1m and 5m resolution have been generated and compared against each other. Effects of building ridge lines and their contribution to catchment delineation has been studied by generating a DSM of 1m resolution, and comparing the results with catchments delineated using 1m DEM. In order to assess the effects of the types of DEM over catchment delineation, a grid based DEM and TIN based DEM are compared against each other using WMS 7.1 software. The results for the catchment delineation using various software illustrate that ArcHydro 10.1 performs better than any other aforementioned software. Also, it is noted that varied drainage threshold area parameters, resolutions of DEM, selection of DEM

  9. 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

  10. Examining the Potential Travellers in Catchment Areas for Public Transport

    DEFF Research Database (Denmark)

    Landex, Alex; Hansen, Stephen

    2006-01-01

    The paper presents a method to examine the catchment areas for stops in high quality public transport systems based on the actual street network in the examined area. This is achieved by implementing the service area functions from the ArcGIS extension Network Analyst. The method is compared...... to a more simple method using only the Euclidean distance from the examined stop and the paper describes the differences in detail-level of the results. Furthermore, the paper describes how the Network Analyst method can be use to examine improvements in the catchment areas by adding extra entrances...... to stations or by making changes in the street network around the station. It is concluded that the Network Analyst method improves the detail-level and accuracy in catchment area analyses. It is these improvements which makes it possible to examine changes in station entrances and/or street network....

  11. Optimal catchment area and primary PCI centre volume revisited

    DEFF Research Database (Denmark)

    Schoos, Mikkel Malby; Pedersen, Frants; Holmvang, Lene

    2015-01-01

    AIMS: The currently stated optimal catchment population for a pPCI centre is 300,000-1,100,000, resulting in 200-800 procedures/year. pPCI centres are increasing in number even within small geographic areas. We describe the organisation and quality of care after merging two high-volume centres....... The quality of a centre reflects governance, training, resources and pre-hospital triage, rather than catchment population and STEMI incidence, as long as a minimum volume is guaranteed. Resources can be utilised better by merging neighbouring centres, without negative effects on quality of care....

  12. Phytotoxic substances in runoff from forested catchment areas

    Science.gov (United States)

    Grimvall, Anders; Bengtsson, Maj-Britt; Borén, Hans; Wahlström, Dan

    Runoff from different catchment areas in southern Sweden was tested in a root bioassay based on solution cultures of cucumber seedlings. Water samples from agricultural catchment areas produced no signs at all or only weak signs of inhibited root growth, whereas several water samples from catchment areas dominated by mires or coniferous forests produced visible root injuries. The most severe root injuries (very short roots, discolouration, swelling of root tips and lack of root hairs) were caused by samples from a catchment area without local emissions and dominated by old stands of spruce. Fractionation by ultrafiltration showed that the phytotoxic effect of these samples could be attributed to organic matter with a nominal molecular-weight exceeding 1000 or to substances associated with organic macromolecules. Experiments aimed at concentrating phytotoxic compounds from surface water indicated that the observed growth inhibition was caused by strongly hydrophilic substances. Previous reports on phytotoxic, organic substances of natural origin have emphasized interaction between plants growing close together. The presence of phytotoxic substances in runoff indicates that there is also a large-scale dispersion of such compounds.

  13. FISHERY MANAGEMENT IN THE DANUBE CATCHMENT AREA

    Directory of Open Access Journals (Sweden)

    Tomislav Treer

    1999-12-01

    Full Text Available There are three successive regions of the Danube, each of which has to deal with its own problems in fisheries. Sport fishing and ecological recontruction problem matters predominate in the upper flow. These problems also characterize the middle flow, where to a certain extent, commercial fishery is coming into view, while the lower flow has to deal with commercial fishery problems to full extent. The difference is not so much due to the morphometry as to the development and state of the economy of the countries in the river basin, their legislation on fishery and the manner in which the legislation is applied. Numerous dams of the upper flow of the Danube (29 in Germany, 9 in Austria, influence significantly the ichthyocenoses. An extreme example of that is Gabčikovo dam at the Slovak-Hungarian border where fish catch decreased to one fourth. In the lower segment of the Danube fish catch falls down to one third and is followed, by a drastically negative change of fish species composition. The records show that highly valued species as sturgeons, pike and tench are in drastic decline over the last few years. The changes were caused by physical barriers, like dams and weirs, by water pollution, by increasing concentration of nutrients and heavy metals, by poaching and by overexploitation. For all those alarming reasons, some legal interventions in commercial fishery must be undertaken. In the middle flow, where the Danube flows through Croatian territory, there have also been declining trends of bentivore and phytophyl species respectively. The law supports the coexistence of sport and commercial fishery in this area and although sport fishing should be given the advantage, commercial fishing should be rigorously supervised and allowed only when there is a naturally produced surplus. Because of fish migrations and political frontiers of Danube area, it is essential that the neighboring countries coordinate their efforts in managing fisheries

  14. The scaling method of specific catchment area from DEMs

    Institute of Scientific and Technical Information of China (English)

    YANG Xin; TANG Guoan; XlAO Chenchao; GAO Yiping; ZHU Shijie

    2011-01-01

    Specific Catchment Area (SCA) is defined as the upstream catchment area of a unit contour.As one of the key terrain parameters,it is widely used in the modeling of hydrology,soil erosion and ecological environment.However,SCA value changes significantly at different DEM resolutions,which inevitably affect terrain analysis results.SCA can be described as the ratio of Catchment Area (CA) and DEM grid length.In this paper,the scale effect of CA is firstly investigated.With Jiuyuangou Gully,a watershed about 70 km2 in northern Shaanxi Province of China,as the test area,it is found that the impacts of DEM scale on CA are different in spatial distribution.CA value in upslope location becomes bigger with the decrease of the DEM resolution.When the location is close to downstream areas the impact of DEM scale on CA is gradually weakening.The scale effect of CA can be concluded as a mathematic trend of exponential decline.Then,a downscaling model of SCA is put forward by introducing the scale factor and the location factor.The scaling model can realize the conversion of SCA value from a coarse DEM resolution to a finer one at pixel level.Experiment results show that the downscaled SCA was well revised,and consistent with SCA at the target resolution with respect to the statistical indexes,histogram and spatial distribution.With the advantages of no empirical parameters,the scaling model could be considered as a simple and objective model for SCA scaling in a rugged drainage area.

  15. ECOLOGICAL ASPECTS OF BENTHIC COMMUNITIES FROM SOMESUL CALD CATCHMENT AREA

    Directory of Open Access Journals (Sweden)

    Karina Battes

    2001-01-01

    Full Text Available The present paper represents a preliminary study of periphyton and zoobenthos community from the Someşul Cald catchment area. Zoobenthos was sampled seasonally during 2000. Benthic community structure was similar at the five sampling sites. Thus, mayflies and chironomids recorded high numerical percentage abundances and densities. Oligochaetes, water mites and caddisflies were identified to species level. 38 Oligochaeta, 28 water mite and 12 caddis fly species were found in the sampling period. The samplings collected in the year 2001 included 80 algal species belonging to 5 phyla. Diatoms (Bacillariophyta dominated both qualitatively and quantitatively at all sampling sites.

  16. IMAGERY: A CASE STUDY IN KAYANGAN CATCHMENT AREA, YOGYAKARTA, INDONESIA

    Directory of Open Access Journals (Sweden)

    Ratih Fitria Putri

    2013-01-01

    Full Text Available The differential synthetic aperture radar in terferometry (DInSAR technique is applied to the ALOS PALSAR data to observe su rface displacement in Kayangan catchment area, Yogyakarta, Indonesia. Change detecti on is implemented to extract information on several landslides that occurred in the region in a time span between 2007 and 2009. The advanced DInSAR processing of im ages (2007–2009 has shown slight surface movements before the landslide events. These results are compared and validated with available GPS measurements. Our analysis reveals that Kayangan catchment area exhibits clear indication of surface displacements varying from 5.2 to 57.9 cm/year. The occurence of landslides has been analy zed in relation to the following terrain parameters; elevation, slope, distance to stream network, geology, landuse, and distance from road. Among these factors, it is found that 18% of landslides occur in elevation >100 m, 56% in slope 30–40°, 34% in <25 m distance to stream networks, 100% in kebobutak formation, 67% in mix garden of land use types, and 100% in <25 m distance from road. The landuse is the most in fluential factor, since there are only four types of landuse that can lead to lands lide occurrence, i.e., mixed garden, dryland agriculture, bush, and settlement. The analys is of land deformation is promising for assessing acceleration caused by a destabilizing anthropogenic change, and relationship between seasonal precipitation a nd deformation variability.

  17. Geochemistry of terricolous lichens in the White Sea catchment area

    Science.gov (United States)

    Shevchenko, V. P.; Pokrovsky, O. S.; Starodymova, D. P.; Vasyukova, E. V.; Lisitzin, A. P.; Drovnina, S. I.; Zamber, N. S.; Makhnovich, N. M.; Savvichev, A. S.; Sonke, J.

    2013-05-01

    This paper presents new data on the multielemental composition of terricolous lichens in the White Sea catchment area. The content of 51 chemical elements was determined in 31 samples using modern analytical methods. It was shown that the chemical composition of terricolous lichens varies widely and depends on many factors. The lithogenic dust plays the main role in accumulation of Ti, Cr, Co, Ga, Fe, Zr, Nb, Ga, Th, U, and REE. Long-range transport from remote pollution sources is important for Pb, Zn, Cd, Bi, Hg, and Se. The Kostomuksha ore dressing mill provides the local enrichment of the lichens in Fe, whereas the Monchegorsk copper-nickel enterprise affects large distances and additionally enriches the lichens in Cu, Ni, Co, Pb, and Cd in comparison with the background regions. The marine impact is reflected in elevated contents and enrichment factors in Na, Mg, and the Na/K ratio.

  18. 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...

  19. New Information on the Malacofauna of the Catchment Area of Rusenski Lom River (North Bulgaria

    Directory of Open Access Journals (Sweden)

    Iltcho Kolev

    2015-12-01

    Full Text Available After this short note adding 8 species to the faunal list of the area, a total of 130 mollusk species are known from the catchment area of Rusenski Lom River both aquatic and terrestrial.

  20. Utilizing Geographic Information System for Prediction of Soil Erosion in Sono Sragen Catchment Area

    OpenAIRE

    Muhammad Mukhlisin; Sukoco

    2011-01-01

    Problem statement: Embung is a small dam created by manmade lakes and used to catch water during rainy season for an irrigation source. In Sragen area, Embung Sono is one of around twenty embung that used to catch rain water for irrigation. Soil erosions in catchment area are potential to reduce water capacity of the embung. Although many embung have been constructed in Sragen areas, the numbers of soil erosion in catchment area of embung are not well considered. Approach:...

  1. Hydrological Dynamics In High Mountain Catchment Areas of Central Norway

    Science.gov (United States)

    Löffler, Jörg; Rößler, Ole

    Large-scaled landscape structure is regarded as a mosaic of ecotopes where process dynamics of water and energy fluxes are analysed due to its effects on ecosystem functioning. The investigations have been carried out in the continental most Vågå/Oppland high mountains in central Norway since 1994 (LÖFFLER &WUNDRAM 1999, 2000, 2001). Additionally, comparable investigations started in 2000 dealing with the oceanic high mountain landscapes on same latitudes (LÖFFLER et al. 2001). The theoretical and methodological framework of the project is given by the Landscape-Ecological Complex Analysis (MOSIMANN 1984, 1985) and its variations due to technical and principle methodical challenges in this high mountain landscape (KÖHLER et al. 1994, LÖFFLER 1998). The aim of the project is to characterize high mountain ecosystem structure, functioning and dynamics within small catchment areas, that are chosen in two different altitudinal belts each in the eastern continental and the western oceanic region of central Norway. In the frame of this research project hydrological and meteorological measurements on ground water, percolation and soil moisture dynamics as well as on evaporation, air humidity and air-, surface- and soil-temperatures have been conducted. On the basis of large-scaled landscape-ecological mappings (LÖFFLER 1997) one basic meteorological station and several major data logger run stations have been installed in representative sites of each two catchment areas in the low and mid alpine belts of the investigation regions ( JUNGet al. 1997, LÖFFLER &WUNDRAM 1997). Moreover, spatial differentiations of groundwater level, soil moisture and temperature profiles have been investigated by means of hand held measurements at different times of the day, during different climatic situations and different seasons. Daily and annual air-, surface- and soil-temperature dynamics are demonstrated by means of thermoisopleth-diagrams for different types of ecotopes of the

  2. Accessibility of tertiary hospitals in Finland: A comparison of administrative and normative catchment areas.

    Science.gov (United States)

    Huotari, Tiina; Antikainen, Harri; Keistinen, Timo; Rusanen, Jarmo

    2017-06-01

    The determination of an appropriate catchment area for a hospital providing highly specialized (i.e. tertiary) health care is typically a trade-off between ensuring adequate client volumes and maintaining reasonable accessibility for all potential clients. This may pose considerable challenges, especially in sparsely inhabited regions. In Finland, tertiary health care is concentrated in five university hospitals, which provide services in their dedicated catchment areas. This study utilizes Geographic Information Systems (GIS), together with grid-based population data and travel-time estimates, to assess the spatial accessibility of these hospitals. The current geographical configuration of the hospitals is compared to a normative assignment, with and without capacity constraints. The aim is to define optimal catchment areas for tertiary hospitals so that their spatial accessibility is as equal as possible. The results indicate that relatively modest improvements can be achieved in accessibility by using normative assignment to determine catchment areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Catchment management in semi-arid area of central South Africa ...

    African Journals Online (AJOL)

    Catchment management in semi-arid area of central South Africa: Strategy for improving water productivity. ... (IRWH) technique recently introduced into a part of the basin occupied by communal farmers has been shown to increase maize and ...

  4. Geographic variations in heart failure hospitalizations among medicare beneficiaries in the Tennessee catchment area.

    Science.gov (United States)

    Ogunniyi, Modele O; Holt, James B; Croft, Janet B; Nwaise, Isaac A; Okafor, Henry E; Sawyer, Douglas B; Giles, Wayne H; Mensah, George A

    2012-01-01

    Although differences in heart failure (HF) hospitalization rates by race and sex are well documented, little is known about geographic variations in hospitalizations for HF, the most common discharge diagnosis for Medicare beneficiaries. Using exploratory spatial data analysis techniques, the authors examined hospitalization rates for HF as the first-listed discharge diagnosis among Medicare beneficiaries in a 10-state Tennessee catchment area, based on the resident states reported by Tennessee hospitals from 2000 to 2004. The age-adjusted HF hospitalization rate (per 1000) among Medicare beneficiaries was 23.3 [95% confidence interval (CI), 23.3-23.4] for the Tennessee catchment area, 21.4 (95% CI, 21.4-21.5) outside the catchment area and 21.9 (95% CI, 21.9-22.0) for the overall United States. The age-adjusted HF hospitalization rates were also significantly higher in the catchment area than outside the catchment area and overall, among men, women and whites, whereas rates among the blacks were higher outside the catchment area. Beneficiaries in the catchment area also had higher age-specific HF hospitalization rates. Among states in the catchment area, the highest mean county-level rates were in Mississippi (30.6 ± 7.6) and Kentucky (29.2 ± 11.5), and the lowest were in North Carolina (21.7 ± 5.7) and Virginia (21.8 ± 6.6). Knowledge of these geographic differences in HF hospitalization rates can be useful in identifying needs of healthcare providers, allocating resources, developing comprehensive HF outreach programs and formulating policies to reduce these differences.

  5. First Flush Effects in an Urban Catchment Area in Aalborg

    DEFF Research Database (Denmark)

    Larsen, Torben; Brpch, Kirsten; Andersen, Margit Riis

    1997-01-01

    The paper describes the results of measurements from a 2 year period on a 95 hectare urban catchment in Aalborg, Denmark. The results of the rain/discharge measurements include 160 storm events corresponding to an accumulated rain depth of totally 753 mm. The water quality measurements include 15...

  6. First Flush Effects in an Urban Catchment Area in Aalborg

    DEFF Research Database (Denmark)

    Larsen, Torben; Broch, Kirsten; Andersen, Margit Riis

    1997-01-01

    The paper describes the results of measurements from a 2 year period on a 95 hectare urban catchment in Aalborg, Denmark. The results of the rain/discharge measurements include 160 storm events corresponding to an accumulated rain depth of totally 753 mm. The water quality measurements include 15...

  7. Seasonal rainfall predictability over the Lake Kariba catchment area

    African Journals Online (AJOL)

    2013-10-24

    Oct 24, 2013 ... an extreme range of conditions across the catchment and through time. Marked ..... system for seasonal rainfall downscaling (Landman et al.,. 2012; Landman and ..... and Zambia issued flood warnings to districts adjacent to the .... pled atmosphere–ocean general circulation model. Mon. Weather. Rev.

  8. Integrated catchment modelling in a Semi-arid area

    CSIR Research Space (South Africa)

    Bugan, Richard DH

    2010-09-01

    Full Text Available , will increasingly need water quality and quantity management tools to be able to make informed decisions. Integrated catchment modelling (ICM) is regarded as being a valuable tool for integrated water resource management. It enables officials and scientists to make...

  9. THE FORMATION OF THE OUTFLOW IN THE URBANISED CATCHMENT AREA ON THE EXAMPLE OF THE CATCHMENT OF STRZYŻA

    OpenAIRE

    Magda Sikora; Roman Cieśliński

    2015-01-01

    The aim of the study is to determine what influence made various forms of land use of catchment area on the size and variability of the outflow. Linking the flow rate with the forms of land use will determine which factors affect the runoff in the basin. The object of the research is Strzyża river basin situated within the administrative boundaries of the city of Gdańsk. It was found that streams flowing through urban areas, including the city of Gdańsk (river Strzyża), quickly react to any e...

  10. Determining health-care facility catchment areas in Uganda using data on malaria-related visits.

    Science.gov (United States)

    Zinszer, Kate; Charland, Katia; Kigozi, Ruth; Dorsey, Grant; Kamya, Moses R; Buckeridge, David L

    2014-03-01

    To illustrate the use of a new method for defining the catchment areas of health-care facilities based on their utilization. The catchment areas of six health-care facilities in Uganda were determined using the cumulative case ratio: the ratio of the observed to expected utilization of a facility for a particular condition by patients from small administrative areas. The cumulative case ratio for malaria-related visits to these facilities was determined using data from the Uganda Malaria Surveillance Project. Catchment areas were also derived using various straight line and road network distances from the facility. Subsequently, the 1-year cumulative malaria case rate was calculated for each catchment area, as determined using the three methods. The 1-year cumulative malaria case rate varied considerably with the method used to define the catchment areas. With the cumulative case ratio approach, the catchment area could include noncontiguous areas. With the distance approaches, the denominator increased substantially with distance, whereas the numerator increased only slightly. The largest cumulative case rate per 1000 population was for the Kamwezi facility: 234.9 (95% confidence interval, CI: 226.2-243.8) for a straight-line distance of 5 km, 193.1 (95% CI: 186.8-199.6) for the cumulative case ratio approach and 156.1 (95% CI: 150.9-161.4) for a road network distance of 5 km. Use of the cumulative case ratio for malaria-related visits to determine health-care facility catchment areas was feasible. Moreover, this approach took into account patients' actual addresses, whereas using distance from the facility did not.

  11. Identification of Hospital Catchment Areas Using Clustering: An Example from the NHS

    Science.gov (United States)

    Gilmour, Stuart John

    2010-01-01

    Objective To develop a method of hospital market area identification using multivariate data, and compare it with existing standard methods. Data Sources Hospital Episode Statistics, a secondary dataset of admissions data from all hospitals in England, between April 2005 and March 2006. Study Design Seven criteria for catchment area definition were proposed. K-means clustering was used on several variables describing the relationship between hospitals and local authority districts (LADs) to enable the placement of every LAD into or out of the catchment area for every hospital. Principal component analysis confirmed the statistical robustness of the method, and the method was compared against existing methods using the seven criteria. Principal Findings Existing methods for identifying catchment areas do not capture desirable properties of a hospital market area. Catchment areas identified using K-means clustering are superior to those identified using existing Marginal methods against these criteria and are also statistically robust. Conclusions K-means clustering uses multivariate data on the relationship between hospitals and geographical units to define catchment areas that are both statistically robust and more informative than those obtained from existing methods. PMID:20050933

  12. Modelling runoff dynamics from information on river network and shape of catchment area

    Science.gov (United States)

    Skaugen, T.

    2009-12-01

    In a new approach, the dynamics of discharge is derived from the distribution of distances to the nearest river reach within a natural catchment. The river network and the shape of catchment provide a unique distribution function for each catchment which can be determined from a GIS. The distribution can be considered as a detailed description of the drainage density, where the location of the river relative to the catchment is taken into account. Within a fixed time interval, water flows through the catchment a certain distance which defines a fractional area. This fraction is estimated as an area enveloping the river network, whose width, perpendicular to the river network, is determined for the time interval of interest by the flow velocity. For a constant flow velocity, the time steps define adjacent areas which , for a sufficient number of time intervals, cover the entire catchment. For different flow velocities, we have different horizontal layers and the total discharge is the sum of discharge from each of the layers for each time step. The proposed principle for modelling the dynamics of discharge is implemented in the Swedish HBV model. The new model, named 3D (distance distribution dynamics), has the same precision as the HBV model but requires fewer parameters and represents thus a step in the right direction for meeting the challenge of predictions in ungauged basins.

  13. Use of modeling to protect, plan, and manage water resources in catchment areas.

    Science.gov (United States)

    Constant, Thibaut; Charrière, Séverine; Lioeddine, Abdejalil; Emsellem, Yves

    2016-08-01

    The degradation of water resources by diffuse pollution, mainly due to nitrate and pesticides, is an important matter for public health. Restoration of the quality of natural water catchments by focusing on their catchment areas is therefore a national priority in France. To consider catchment areas as homogeneous and to expend an equal effort on the entire area inevitably leads to a waste of time and money, and restorative actions may not be as efficient as intended. The variability of the pedological and geological properties of the area is actually an opportunity to invest effort on smaller areas, simply because every action is not equally efficient on every kind of pedological or geological surface. Using this approach, it is possible to invest in a few selected zones that will be efficient in terms of environmental results. The contributive hydraulic areas (CHA) concept is different from that of the catchment area. Because the transport of most of the mobile and persistent pollutants is primarily driven by water circulation, the concept of the CHA is based on the water pathway from the surface of the soil in the catchment area to the well. The method uses a three-dimensional hydrogeological model of surface and groundwater integrated with a geographic information system called Watermodel. The model calculates the contribution (m(3)/h or %) of each point of the soil to the total flow pumped in a well. Application of this model, partially funded by the Seine Normandy Basin Agency, to the catchment of the Dormelles Well in the Cretaceous chalk aquifer in the Orvanne valley, France (catchment area of 23,000 ha at Dormelles, county 77), shows that 95 % of the water pumped at the Dormelles Well comes from only 26 % of the total surface area of the catchment. Consequently, an action plan to protect the water resource will be targeted at the 93 farmers operating in this source area rather than the total number of farmers (250) across the entire 23,000 ha. Another

  14. Fungicides transport in runoff from vineyard plot and catchment: contribution of non-target areas.

    Science.gov (United States)

    Lefrancq, Marie; Payraudeau, Sylvain; García Verdú, Antonio Joaquín; Maillard, Elodie; Millet, Maurice; Imfeld, Gwenaël

    2014-04-01

    Surface runoff and erosion during the course of rainfall events are major processes of pesticides transport from agricultural land to aquatic ecosystem. These processes are generally evaluated either at the plot or the catchment scale. Here, we compared at both scales the transport and partitioning in runoff water of two widely used fungicides, i.e., kresoxim-methyl (KM) and cyazofamid (CY). The objective was to evaluate the relationship between fungicides runoff from the plot and from the vineyard catchment. The results show that seasonal exports for KM and CY at the catchment were larger than those obtained at the plot. This underlines that non-target areas within the catchment largely contribute to the overall load of runoff-associated fungicides. Estimations show that 85 and 62 % of the loads observed for KM and CY at the catchment outlet cannot be explained by the vineyard plots. However, the partitioning of KM and CY between three fractions, i.e., the suspended solids (>0.7 μm) and two dissolved fractions (i.e., between 0.22 and 0.7 µm and catchment and the plot scales enable to evaluate the sources areas of pesticide off-site transport.

  15. The Population Burden of Cancer: Research Driven by the Catchment Area of a Cancer Center.

    Science.gov (United States)

    Tai, Caroline G; Hiatt, Robert A

    2017-01-01

    Cancer centers, particularly those supported by the National Cancer Institute, are charged with reducing the cancer burden in their catchment area. However, methods to define both the catchment area and the cancer burden are diverse and range in complexity often based on data availability, staff resources, or confusion about what is required. This article presents a review of the current literature identifying 4 studies that have defined various aspects of the cancer burden in a defined geographical area and highlights examples of how some cancer centers and other health institutions have defined their catchment area and characterized the cancer burden within it. We then present a detailed case study of an approach applied by the University of California, San Francisco, Helen Diller Family Comprehensive Cancer Center to define its catchment area and its population cancer burden. We cite examples of how the Cancer Center research portfolio addresses the defined cancer burden. Our case study outlines a systematic approach to using publicly available data, such as cancer registry data, that are accessible by all cancer centers. By identifying gaps and formulating future research directions based on the needs of the population within the catchment area, epidemiologic studies and other types of cancer research can be directed to the population served. This review can help guide cancer centers in developing an approach to defining their own catchment area as mandated and applying research findings to this defined population. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Catchments network on badlands around Mediterranean area (RESOBAM)

    Science.gov (United States)

    Copard, Yoann; Lebouteiller, Caroline; Regues-Munoz, David; Latron, Jerome; Solé-Benet, Albert; Canton, Yolanda; Nadal-Romero, Estela; Della Seta, Marta; Rossi, Mauro; Capolongo, Domenico; Maquaire, Olivier; Forey, Estelle; Di-Giovanni, Christian; Gallart, Francesc; Delmonte, Maurizio; Vergari, Francesca; Massei, Nicolas; Torri, Dino

    2016-04-01

    Between 2013 and 2014, a network funded by MISTRALS-ENVIMED institution, was born around some instrumented catchments developing a badland-type morphology. This network has grouped 3 countries (France, Spain and Italy) with 12 scientific labs. RESOBAM has concerned two sites in France (Draix-Bléone and Vaches Noires), three in Spain (Vallcebre, Araguas and El Cautivo) and some sites in Italy (Tuscany, Basilicata). Main goal of this network was to federate the research around badlands at the European scale, by proposing some scientific topics as: sediment and water transports / budget, (bio)geochemical cycles, agricultural (farming), education, restoration, cultural heritage, soil conservation / biodiversity, climatic change etc. Other main interests were also to propose some common scientific projects and the development of students exchanges. This communication presents the synthesis of our four meetings held at Draix, Zaragoza, Almeriá and Rouen and some perspectives to continue this network.

  17. IMPACT OF URBANIZATION OF SUBURBAN AREA ON WATER RELATION IN THE SMALL CATCHMENTS

    Directory of Open Access Journals (Sweden)

    Jolanta Kanclerz

    2016-02-01

    Full Text Available This paper presents results of analysis focused on impact of urbanization of Poznań suburban area on water relation for Doływ spod Lusówka and Przeźmierki catchments during 1936–2011. Both catchments are located in municipalities which recently showing sharp growth in urban area. Analysis of changes in land use for studied catchments showed almost 5-fold increase in urban area for Dopływ spod Lusówka and 10-fold for Przeźmierka. As a consequence of land sealing increase in amounts of effective precipitation was observed that led to fast runoff of rain waters and almost double flow in watercourses.

  18. A review on the establishment and research in hydrological experimental areas (catchments) in plain areas in China and abroad

    Science.gov (United States)

    Yang, Hai; Wang, Chuanhai; Hua, Wenjuan

    2017-04-01

    This paper reviewed some specific conceptions of hydrological experimental areas (catchments) while found that the traditional definition of 'catchment' may be difficult to meet in plain areas. According to the review of development history and current situation of hydrological experimental areas (catchments) in plain areas in China, 4 stages were shown besides the recent 10 years, i.e., 'golden stage(1952-1966)', 'backward stage(1966-1986)', 'short recovery stage(1986-1989)' and 'stagnant stage(1986-2006)'. It gets new impetus since 2006 with some investigation work promoted by the government. Furthermore, some historic problems during establishing experimental areas (catchments) in plain areas were revealed based on the document literature and a few meaningful lessons were drawn from the past. It was also the first time to collect and classify the details of both 11 representative experimental areas in China and abroad, after that a brief comparison about the measurement level and research directions was made between two regions. Additionally, we took the experimental research work in the plain of Taihu Lake Basin as example and introduced the particular research goals and the corresponding establishing process, including how to design the experimental area, eg, size, location, land use type, arranging the measurement instruments et al. We hope such case can provide a reference for newly-building, recovering and extending hydrological experimental areasin plain areas in the future. Finally, this paper prospected the future development in establishment and research in hydrological experimental areas (catchments) in plain areas. It may be more common to see the cooperation between model scientists and field experts. Because of the comprehensive goals in water problems, researchers from various fields would work together in the future experimental research work. Scale study and modelling in plain areas will be a promising branch after some typical experimental areas

  19. THE FORMATION OF THE OUTFLOW IN THE URBANISED CATCHMENT AREA ON THE EXAMPLE OF THE CATCHMENT OF STRZYŻA

    Directory of Open Access Journals (Sweden)

    Magda Sikora

    2015-01-01

    Full Text Available The aim of the study is to determine what influence made various forms of land use of catchment area on the size and variability of the outflow. Linking the flow rate with the forms of land use will determine which factors affect the runoff in the basin. The object of the research is Strzyża river basin situated within the administrative boundaries of the city of Gdańsk. It was found that streams flowing through urban areas, including the city of Gdańsk (river Strzyża, quickly react to any excess water. Heavy rain combined with the discharge of water through the storm sewer system results of increasing the flow and runoff in streams, among others, Strzyża river.

  20. Karst groundwater protection in the Kupa River catchment area and sustainable development

    Science.gov (United States)

    Biondić, B.; Biondić, R.; Kapelj, S.

    2006-03-01

    One of the most significant water resources in the Republic of Croatia is the catchment area of the Kupa River, located in the region bordering the Republic of Slovenia. About 88% of the total amount of water in this catchment originates in Croatia and just 12% from Slovenia; therefore, the largest part of the catchment area (about 1000 km2) is on the Croatian side of the border. It is a typical karst area of the Dinarides with aquifers characterized by a relatively rapid water exchange, high groundwater flow velocities and aquifers open to human impact from the surface. Consequently, the aquifers are highly vulnerable and at risk. Due to the availability of large quantities of high-quality spring water (about 6 m3/s), the entire area has a strategic importance within the context of any future development strategy pertaining to the western part of Croatia. The catchment area on the Croatian side was investigated using a wide range of research methods that included a classical hydrogeological approach, the detailed hydrologic calculation of water balance to the hydrogeochemical analyses and modelling. The objective was to determine protection zones and protection measures for the whole area. The difficulties are increased due to the fact that the karst catchment area is crossed by major traffic corridors, oil pipelines and a railway and that many settlements and a highly developed wood industry are present. The combination of protecting water resources with adequate prevention measures and necessary remedial activities that should satisfy the very strict requirements necessary for the protection of the karst aquifers while still allowing for present and future human activities is difficult but not impossible to achieve. One good example is the present highway with a closed dewatering system and waste water treatment before the water passes into the karst underground system.

  1. Catchment management in semi-arid area of central South Africa ...

    African Journals Online (AJOL)

    South Africa: Strategy for improving water productivity. YE Woyessa1*, M ... for water. This accentuates the need for wise decisions by catchment management agencies (CMAs), espe- ... the natural systems. ..... 8 provide additional economic support .... vation techniques on small plots in semi-arid areas to enhance rain-.

  2. Variability of rainfall over Lake Kariba catchment area in the Zambezi river basin, Zimbabwe

    Science.gov (United States)

    Muchuru, Shepherd; Botai, Joel O.; Botai, Christina M.; Landman, Willem A.; Adeola, Abiodun M.

    2016-04-01

    In this study, average monthly and annual rainfall totals recorded for the period 1970 to 2010 from a network of 13 stations across the Lake Kariba catchment area of the Zambezi river basin were analyzed in order to characterize the spatial-temporal variability of rainfall across the catchment area. In the analysis, the data were subjected to intervention and homogeneity analysis using the Cumulative Summation (CUSUM) technique and step change analysis using rank-sum test. Furthermore, rainfall variability was characterized by trend analysis using the non-parametric Mann-Kendall statistic. Additionally, the rainfall series were decomposed and the spectral characteristics derived using Cross Wavelet Transform (CWT) and Wavelet Coherence (WC) analysis. The advantage of using the wavelet-based parameters is that they vary in time and can therefore be used to quantitatively detect time-scale-dependent correlations and phase shifts between rainfall time series at various localized time-frequency scales. The annual and seasonal rainfall series were homogeneous and demonstrated no apparent significant shifts. According to the inhomogeneity classification, the rainfall series recorded across the Lake Kariba catchment area belonged to category A (useful) and B (doubtful), i.e., there were zero to one and two absolute tests rejecting the null hypothesis (at 5 % significance level), respectively. Lastly, the long-term variability of the rainfall series across the Lake Kariba catchment area exhibited non-significant positive and negative trends with coherent oscillatory modes that are constantly locked in phase in the Morlet wavelet space.

  3. Late Pleistocene and Holocene landscape formation in a gully catchment area in Northern Hesse, Germany

    DEFF Research Database (Denmark)

    Döhler, Susanne; Damm, Bodo; Terhorst, Birgit

    2015-01-01

    Permanent gully channels under forest are common geomorphological features in Central European low mountain areas. In the Rehgraben/Fuchslöchergraben gully catchment in Northern Hesse, Germany the Late Pleistocene landscape formation is reconstructed based on periglacial cover beds. In addition...

  4. Late Pleistocene and Holocene landscape formation in a gully catchment area in Northern Hesse, Germany

    DEFF Research Database (Denmark)

    Döhler, Susanne; Damm, Bodo; Terhorst, Birgit

    2015-01-01

    Permanent gully channels under forest are common geomorphological features in Central European low mountain areas. In the Rehgraben/Fuchslöchergraben gully catchment in Northern Hesse, Germany the Late Pleistocene landscape formation is reconstructed based on periglacial cover beds. In addition...

  5. Mapping Model of Groundwater Catchment Area based on Geological Fault : Case Study in Semarang City

    Directory of Open Access Journals (Sweden)

    Qudus, N.

    2016-04-01

    Full Text Available Groundwater is a naturally renewable resource because groundwater is an integral part of hydrological cycle. However, in reality, there are many limiting factors which influence its usage, in both quality and quantity, the provision ability of groundwater will decrease if its availability is exceeded. The problems of ground water potential in both quantity and quality are always related to its constituents' characteristics or its geological element where the groundwater resides. This present study aims at determining the groundwater catchment area based on the geological condition of an area so that groundwater recharge can be accomplished. In addition, it is necessary for groundwater catchment area to comply with the geological condition. The geologically unfit area will only result in land movement or landslide if it is used as groundwater catchment area. The results of geo-electricity analysis which was conducted in Semarang city showed that there are 3 faults; Sukorejo fault, Tinjomoyo fault and Jangli fault which will be explained in detail in the paper. Those faults intersect the underground water stream in Semarang from south to north towards the Java Sea. The majority of underground water stream in Semarang flows from south to north. In contrary, the results of the analysis showed that there are some points that become local basins such as in the south area and southwest of Semarang where flow direction is on the opposite direction. In addition, the results of the analysis showed that some coastal areas in Semarang have experienced salt water intrusion.

  6. Diatoms from the Vaal dam catchment area Transvaal, South Africa

    CSIR Research Space (South Africa)

    Archibald, REM

    1971-01-01

    Full Text Available the area around the milk processing factory. pH 8.2. 8. 8. 60. Vaal 418 ? The Vaal River below the Standerton Se wage Works. Station 5 of CHUTTEa. The river bed is granite rock. pH 8.5. 8. 8. 60. Vaal 419 ? The first small stream outside Standerton... variability ii the morphology of the valve. C. pseudostelligera form were present when the silica content of the cultures wa present in sufficient quantities, but, when the silica con tent was low and there was a deficiency, ceils of anothe form were...

  7. Uniform Transnational Assessment of the Environmental Indices from the Romanian Catchment Area of the Tisa River

    Directory of Open Access Journals (Sweden)

    SILVIU-FLORIN FONOGEA

    2010-01-01

    Full Text Available The uniform transnational assessment of the environmental indices in the catchment area of the Tisa river aims at rehabilitating, protecting and conserving the environmental systems, as well as creating a commonly strategic demarche concerning a sustainable spatial development, based on integrated intersectorial approaches of environmental issues, viewed in their territorial dimension. The information necessary in underlining the current situation in the Romanian catchment area of the Tisa has been structured according to the following categories of analysed indices: sources of surface waters, resources of drinkable water and water supply resources, the risk of not reaching the environmental objectives, significant sources of water pollution (punctual sources of pollution, diffuse sources of pollution, significant hydromorphic pressure, the quality of water, significant sources of air pollution, soils affected by agricultural and industrial activities, nature protection and waste management.

  8. Biosorption of heavy metals contaminating the Wonderfonteinspruit Catchment Area using Desmodesmus sp.

    OpenAIRE

    2011-01-01

    A vast array of biological materials, especially algae have received increasing attention for heavy metal removal. Algae have been proven to be cheaper, more effective for the removal of metallic elements in aqueous solutions. A fresh water algal strain was isolated from Zoo Lake, Johannesburg, South Africa and identified as Desmodesmus sp. This paper investigates the efficacy of Desmodesmus sp.in removing heavy metals contaminating the Wonderfonteinspruit Catchment Area (WCA) water bodies. T...

  9. Performance of rainwater harvesting system based on roof catchment area and storage tank capacity

    Directory of Open Access Journals (Sweden)

    Juliana Imroatul C.

    2017-01-01

    Full Text Available Increasing population growth has created problems in water resources. Natural water resources become progressively more expensive and difficult to develop. In addition, it is also becoming increasingly polluted and difficult to obtain. Many countries shown a resurgent interest in the use of rainwater harvesting (RWH technique to overcome these problems. There are several factors that will influence the RWH performance, such as the rainfall, catchment area, storage tank capacity, and water demand. The performance parameter determines by the volumetric reliability, time reliability, and yield. The RWH system used in this study is a simple RWH system that utilizes roof as a catchment area, pipes as a distribution system and tank as a storage. An analysis is carried out to investigate the effect of altering the large of the catchment area and storage tank capacity to the RWH system performance parameters. A suitable behavioral model based on the water balance method is implemented to evaluate the inflow, outflow, and the storage volume. Results demonstrate that with up to 15 years daily rainfall data in 15 cities in Indonesia, the most influential parameters on the performance of RWH system is the time reliability.

  10. Improved methods to estimate the effective impervious area in urban catchments using rainfall-runoff data

    Science.gov (United States)

    Ebrahimian, Ali; Wilson, Bruce N.; Gulliver, John S.

    2016-05-01

    Impervious surfaces are useful indicators of the urbanization impacts on water resources. Effective impervious area (EIA), which is the portion of total impervious area (TIA) that is hydraulically connected to the drainage system, is a better catchment parameter in the determination of actual urban runoff. Development of reliable methods for quantifying EIA rather than TIA is currently one of the knowledge gaps in the rainfall-runoff modeling context. The objective of this study is to improve the rainfall-runoff data analysis method for estimating EIA fraction in urban catchments by eliminating the subjective part of the existing method and by reducing the uncertainty of EIA estimates. First, the theoretical framework is generalized using a general linear least square model and using a general criterion for categorizing runoff events. Issues with the existing method that reduce the precision of the EIA fraction estimates are then identified and discussed. Two improved methods, based on ordinary least square (OLS) and weighted least square (WLS) estimates, are proposed to address these issues. The proposed weighted least squares method is then applied to eleven urban catchments in Europe, Canada, and Australia. The results are compared to map measured directly connected impervious area (DCIA) and are shown to be consistent with DCIA values. In addition, both of the improved methods are applied to nine urban catchments in Minnesota, USA. Both methods were successful in removing the subjective component inherent in the analysis of rainfall-runoff data of the current method. The WLS method is more robust than the OLS method and generates results that are different and more precise than the OLS method in the presence of heteroscedastic residuals in our rainfall-runoff data.

  11. Water catchment areas: Tools for management and control of hazardous compounds - WATCH

    Energy Technology Data Exchange (ETDEWEB)

    Track, T.; Huntley, S.; Setford, S.; Barcelo, D.; Rosell, M.; Wijdens, J.; Vermot-Desroches, C.; Werner, P.; Fahl, J.; Rohns, H.-P.; Forner, C.; Hitsch, E.; Brun, A.; Jensen, B. [Dechema e.V., Frankfurt/Main (Germany)

    2003-07-01

    The focus of WATCH is on the creation of early warning systems to identify potential contamination threats to groundwater resources in catchment areas of waterworks. The goal is a sustainable protection and use of drinking water resources. MTBE (methyl tert-butyl ether) and BTEX (benzene, toluene, ethylbenzene, m-, o-, p-xylene) compounds were selected as exemplary contaminants that will be considered. Main objectives are (1) to develop and implement analytical methods and instrumentation for in-situ monitoring of BTEX and MTBE in groundwater and sediment (2) an integrated at-site early warning and management tool on a catchment scale (3) evaluation of both objectives on-site. Other objectives include use of oil leak sensors to indicate soil contamination, development and in-situ testing of optical reflectance sensors and rapid on site immunoassay kits, a protocol for sample handling and analysis of BTEX and MTBE, development of a BTEX and MTBE database for degradation behaviour, incl. degradation pathways and inhibition/stimulation assessment for MTBE. The sensors and monitoring system will be tested at 2 end users. Also design of an integrated management tool for catchment areas with contaminant sources, including a risk management and reduction strategy will be addressed. (orig.)

  12. Using Spatial Analysis to Investigate Geographic Variations in Heart Failure Hospitalizations among Medicare Beneficiaries in the Tennessee Catchment Area

    Science.gov (United States)

    Ogunniyi, Modele O.; Holt, James B.; Croft, Janet B.; Nwaise, Isaac A.; Okafor, Henry E.; Sawyer, Douglas B.; Giles, Wayne H.; Mensah, George A.

    2014-01-01

    Introduction Although differences in heart failure hospitalization rates by race and sex are well documented, little is known about geographic variations in hospitalization rates for heart failure among Medicare beneficiaries. Methods Using exploratory spatial data analysis techniques, we examined hospitalization rates for heart failure as the first-listed discharge diagnosis among Medicare beneficiaries in a 10-state Tennessee catchment area, based on the resident states reported by Tennessee hospitals from 2000 to 2004. Results The age-adjusted heart failure hospitalization rate (per 1,000) among Medicare beneficiaries was 23.3 (95% confidence interval [CI], 23.3–23.4) for the Tennessee catchment area, 21.4 (95% CI, 21.4 -21.5) for the non-catchment US area and 21.9 (95% CI, 21.9–22.0) for the overall US. The age-adjusted HF hospitalization rates were also significantly higher in the catchment area than the non catchment US area and the overall US, among men, women, and whites, whereas rates among the blacks were higher outside the catchment area. Beneficiaries in the catchment area also had higher age-specific HF hospitalization rates. Among states in the catchment area, the highest mean county-level rates were in Mississippi (30.6±7.6) and Kentucky (29.2±11.5), and the lowest were in North Carolina (21.7±5.7), closely and Virginia (21.8±6.6). Conclusions Knowledge of geographic differences in rates of hospitalization for heart failure can be useful in identifying needs of health care providers, allocating resources, developing comprehensive heart failure outreach programs, and formulating policies designed to reduce these differences. PMID:21804374

  13. 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

  14. BISTRIŢA ARDELEANĂ CATCHMENT AREA – COORDINATES OF STRATEGIC LAND MANAGEMENT

    Directory of Open Access Journals (Sweden)

    S. F. FONOGEA

    2014-11-01

    Full Text Available Bistriţa Ardeleană Catchment Area – Coordinates of Strategic Land Management. The approach of “creation and execution” / designing of this territorial cut-out of basin type, in the paradigmatic context of the durable development, is subordinate to an (almostexhaustive investigation of the vocation and potentiality of this area in terms of geographical and spatial organization of the territory. There may be multiple reasons to justify the existence of a paper which approaches this territory in an integrating and prospective manner. First of all, this area has an “identity card” type of evidence, at the level of the collective memory of the county’s inhabitants. Even if many contradictions multiplied along the years, nuances and specificities have been imposed, there is a filiation and a common territorial manifestation for the population and the settlements in this area. Secondly, the building of the settlements from Bârgău area and their later historical evolution was accomplished in a close interdependence, therefore the premise of development cannot be achieved outside the association (the access to different financing sources is easier when partnerships are built. Thirdly, the challenge of developing a study that shows the real prospects of developing a territory from the Bistriţa Ardeleană catchment area was motivated by subjective arguments, and the love of nature and environment played a key role in the effort to complete this action.

  15. Glacier area changes in the Rio Olivares catchment, Central Andes 1955-2013

    Science.gov (United States)

    Malmros, Jeppe.; Wilson, Ryan; Mernild, Sebastian; Fensholt, Rasmus

    2014-05-01

    Here, we present a new glacier inventory for the Rio Olivares catchment (531 km2), Central Chilean Andes (33°14`44 S, 70°07`26 V). Area changes for 145 glaciers were analyzed for the period 1955 through 2013 based on terrestrial photogrammetry, aerial photography, and satellite imagery. The results show that glacier area not including rock glaciers reduced by ~18 % - from 93.8 (1955) to 75.9 km2 (2013), equivalent to an estimated volume loss of 40 % (2.9 km3) based on volume-area scaling functions. Rock glacier area increased from 10.4 (1955) to 10.7 km2 (2013). Additionally, a detailed area, hypsometry, and elevation time series analysis for the five largest glaciers in the catchment was conducted, showing that terminus positions ascended by an average of 351 ± 8 meters and slope increased 0.7° on average. A comparison between changes in glacier area and variations in the El Niño Southern Oscillation index indicates a significant climatic link.

  16. Determining the groundwater potential recharge zone and karst springs catchment area: Saldoran region, western Iran

    Science.gov (United States)

    Karami, Gholam Hossein; Bagheri, Rahim; Rahimi, Fahimeh

    2016-12-01

    Assessing the groundwater recharge potential zone and differentiation of the spring catchment area are extremely important to effective management of groundwater systems and protection of water quality. The study area is located in the Saldoran karstic region, western Iran. It is characterized by a high rate of precipitation and recharge via highly permeable fractured karstic formations. Pire-Ghar, Sarabe-Babaheydar and Baghe-rostam are three major karstic springs which drain the Saldoran anticline. The mean discharge rate and electrical conductivity values for these springs were 3, 1.9 and 0.98 m3/s, and 475, 438 and 347 μS/cm, respectively. Geology, hydrogeology and geographical information system (GIS) methods were used to define the catchment areas of the major karstic springs and to map recharge zones in the Saldoran anticline. Seven major influencing factors on groundwater recharge rates (lithology, slope value and aspect, drainage, precipitation, fracture density and karstic domains) were integrated using GIS. Geology maps and field verification were used to determine the weights of factors. The final map was produced to reveal major zones of recharge potential. More than 80 % of the study area is terrain that has a recharge rate of 55-70 % (average 63 %). Evaluating the water budget of Saldoran Mountain showed that the total volume of karst water emerging from the Saldoran karst springs is equal to the total annual recharge on the anticline. Therefore, based on the geological and hydrogeological investigations, the catchment area of the mentioned karst springs includes the whole Saldoran anticline.

  17. Determining the groundwater potential recharge zone and karst springs catchment area: Saldoran region, western Iran

    Science.gov (United States)

    Karami, Gholam Hossein; Bagheri, Rahim; Rahimi, Fahimeh

    2016-08-01

    Assessing the groundwater recharge potential zone and differentiation of the spring catchment area are extremely important to effective management of groundwater systems and protection of water quality. The study area is located in the Saldoran karstic region, western Iran. It is characterized by a high rate of precipitation and recharge via highly permeable fractured karstic formations. Pire-Ghar, Sarabe-Babaheydar and Baghe-rostam are three major karstic springs which drain the Saldoran anticline. The mean discharge rate and electrical conductivity values for these springs were 3, 1.9 and 0.98 m3/s, and 475, 438 and 347 μS/cm, respectively. Geology, hydrogeology and geographical information system (GIS) methods were used to define the catchment areas of the major karstic springs and to map recharge zones in the Saldoran anticline. Seven major influencing factors on groundwater recharge rates (lithology, slope value and aspect, drainage, precipitation, fracture density and karstic domains) were integrated using GIS. Geology maps and field verification were used to determine the weights of factors. The final map was produced to reveal major zones of recharge potential. More than 80 % of the study area is terrain that has a recharge rate of 55-70 % (average 63 %). Evaluating the water budget of Saldoran Mountain showed that the total volume of karst water emerging from the Saldoran karst springs is equal to the total annual recharge on the anticline. Therefore, based on the geological and hydrogeological investigations, the catchment area of the mentioned karst springs includes the whole Saldoran anticline.

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

    OpenAIRE

    H. Guan; Love, A.; Simmons, C.T.; Ding, Z.; J. Hutson

    2009-01-01

    Among various approaches for estimating groundwater recharge, chloride mass balance (CMB) method is one of the most frequently used, in particular, for arid and semiarid regions. Widespread native vegetation clearance, common history in many areas globally, has changed land surface boundary condition, posing a question whether the current system has reached new chloride equilibrium for CMB application. To examine CMB applicability for catchments, conceptual catchment types of various chloride...

  19. Estimation of snow covered area for an urban catchment using image processing and neural networks.

    Science.gov (United States)

    Matheussen, B V; Thorolfsson, S T

    2003-01-01

    This paper presents a method to estimate the snow covered area (SCA) for small urban catchments. The method uses images taken with a digital camera positioned on top of a tall building. The camera is stationary and takes overview images of the same area every fifteen minutes throughout the winter season. The images were read into an image-processing program and a three-layered feed-forward perceptron artificial neural network (ANN) was used to calculate fractional snow cover within three different land cover types (road, park and roofs). The SCA was estimated from the number of pixels with snow cover relative to the total number of pixels. The method was tested for a small urban catchment, Risvollan in Trondheim, Norway. A time series of images taken during spring of 2001 and the 2001-2002 winter season was used to generate a time series of SCA. Snow covered area was also estimated from aerial photos. The results showed a strong correlation between SCA estimated from the digital camera and the aerial photos. The time series of SCA can be used for verification of urban snowmelt models.

  20. Long term effect of metal pollution in the catchment area of Tisza River

    Directory of Open Access Journals (Sweden)

    Zoltán Győri

    2013-01-01

    Full Text Available In January and March 2000 two tailings dam failures occurred in the upper Tisza catchment area near Baia Mare and Baia Borsa (Romania. These accidents focused attention on the metal pollution of the Tisza catchment area, and the short term effects of them were studied by many researchers. The aim of this study was to evaluate the long term effects of these pollutions by determining the Lakanen-Erviö extractable easily available metal contents of samples collected in 2011 from floodplains and pastures along the Tisza (Tivadar, Vásárosnamény, Rakamaz, Tiszacsege, and comparing them to our earlier results. Cu and Zn contents were measured by Optima 3300 DV ICP-OES (Perkin-Elmer. The measurement of Pb and Cd was conducted by QZ 939 GF-AAS (Unicam in 2000 and by an X7 ICP-MS (Thermo Fisher in 2011. We found that the Cd, Zn and Pb contents of the pasture near Vásárosnamény exceed limit values and natural background values. In addition, during a 11 year period the easily available Cd, Zn and Pb contents increased significantly, suggesting that the hazard of this pollution should not be neglected.

  1. How size matters: exploring the association between quality of mental health services and catchment area size.

    Science.gov (United States)

    Ala-Nikkola, Taina; Sadeniemi, Minna; Kaila, Minna; Saarni, Samuli; Kontio, Raija; Pirkola, Sami; Joffe, Grigori; Oranta, Olli; Wahlbeck, Kristian

    2016-08-12

    The diversity of mental health and substance abuse services (MHS) available to service users is seen as an indicator of the quality of the service system. In most countries MHS are provided by a mix of public, private and third sector providers. In Finland, officially, the municipalities are responsible for organizing the services needed, but the real extent and roles of private and third sector service providers are not known. Our previous study showed that the catchment area population size was strongly associated with diversity of mental health services. It is not known whether this was due to some types of services or some provider types being more sensitive to the size effect than others. The aim of this study was to investigate the association between area population size and diversity of mental health services, i.e. which types of services and which service providers' contributions are sensitive to population size. To map and classify services, we used the ESMS-R. The diversity of services was defined as the count of main types of care. Providers were classified as public, private or third sectors. The diversity of outpatient, residential and voluntary services correlated positively with catchment area population size. The strongest positive correlation between the size of population and services available was found in third sector activities followed by public providers, but no correlation was found for diversity of private services. The third sector and public corporations each provided 44 % of the service units. Third sector providers produced all self-help services and most of the day care services. Third sector and private companies provided a significant part (59 %) of the residential care service units. Significant positive correlations were found between size of catchment area population and diversity of residential, outpatient and voluntary services, indicating that these services concentrate on areas with larger population bases. The third sector

  2. Effects of Channelisation, Riparian Structure and Catchment Area on Physical Habitats in Small Lowland Streams

    DEFF Research Database (Denmark)

    Pedersen, Morten Lauge

    2009-01-01

    that are dominated by a hierarchy of physical processes. The complexity is further enhanced by local human alteration of the physical structure, natural processes and alteration of the riparian areas. The aim of the study was to analyse variations in land use and riparian characteristics along small Danish streams......Rivers and streams form a longitudinal network in which physical conditions and biological processes change through the river system. Geomorphology, topography, geology and hydraulic conditions change from site to site within the river system, thereby creating a complex network of reaches...... and to determine the effect of channelisation on physical habitats. Physical stream characteristics were measured in 149 stream small and medium sized Danish streams (catchment area: 0.1 to 67.2 km2). The measured physical parameters included discharge, stream slope, width, depth, current velocity, substrata...

  3. Spatial accessibility of primary health care utilising the two step floating catchment area method: an assessment of recent improvements

    Directory of Open Access Journals (Sweden)

    McGrail Matthew R

    2012-11-01

    Full Text Available Abstract Background The two step floating catchment area (2SFCA method has emerged in the last decade as a key measure of spatial accessibility, particularly in its application to primary health care access. Many recent ‘improvements’ to the original 2SFCA method have been developed, which generally either account for distance-decay within a catchment or enable the usage of variable catchment sizes. This paper evaluates the effectiveness of various proposed methods within these two improvement groups. Moreover, its assessment focuses on how well these improvements operate within and between rural and metropolitan populations over large geographical regions. Results Demonstrating these improvements to the whole state of Victoria, Australia, this paper presents the first comparison between continuous and zonal (step decay functions and specifically their effect within both rural and metropolitan populations. Especially in metropolitan populations, the application of either type of distance-decay function is shown to be problematic by itself. Its inclusion necessitates the addition of a variable catchment size function which can enable the 2SFCA method to dynamically define more appropriate catchments which align with actual health service supply and utilisation. Conclusion This study assesses recent ‘improvements’ to the 2SFCA when applied over large geographic regions of both large and small populations. Its findings demonstrate the necessary combination of both a distance-decay function and variable catchment size function in order for the 2SFCA to appropriately measure healthcare access across all geographical regions.

  4. Spatial accessibility of primary health care utilising the two step floating catchment area method: an assessment of recent improvements.

    Science.gov (United States)

    McGrail, Matthew R

    2012-11-16

    The two step floating catchment area (2SFCA) method has emerged in the last decade as a key measure of spatial accessibility, particularly in its application to primary health care access. Many recent 'improvements' to the original 2SFCA method have been developed, which generally either account for distance-decay within a catchment or enable the usage of variable catchment sizes. This paper evaluates the effectiveness of various proposed methods within these two improvement groups. Moreover, its assessment focuses on how well these improvements operate within and between rural and metropolitan populations over large geographical regions. Demonstrating these improvements to the whole state of Victoria, Australia, this paper presents the first comparison between continuous and zonal (step) decay functions and specifically their effect within both rural and metropolitan populations. Especially in metropolitan populations, the application of either type of distance-decay function is shown to be problematic by itself. Its inclusion necessitates the addition of a variable catchment size function which can enable the 2SFCA method to dynamically define more appropriate catchments which align with actual health service supply and utilisation. This study assesses recent 'improvements' to the 2SFCA when applied over large geographic regions of both large and small populations. Its findings demonstrate the necessary combination of both a distance-decay function and variable catchment size function in order for the 2SFCA to appropriately measure healthcare access across all geographical regions.

  5. Importance of bottom-up approach in water management - sustainable development of catchment areas in Croatia

    Science.gov (United States)

    Pavic, M.; Cosic-Flajsig, G.; Petricec, M.; Blazevic, Z.

    2012-04-01

    Association for preservation of Croatian waters and sea SLAP is a non-governmental organization (NGO) that gathers more than 150 scientist, hydrologist and civil engineers. SLAP has been established in 2006 and since then had organized many conferences and participated in projects dealing with water management. We have started our work developing plans to secure water supply to the 22 (21) villages in the rural parts of Dubrovnik (Pozega) area and trough the years we have accumulated knowledge and experience in dealing with stakeholders in hydrology and water management. Within this paper we will present importance of bottom-up approach to the stakeholders in water management in Croatia on two case studies: (1) Management of River Trebizat catchment area - irrigation of the Imotsko-Bekijsko rural parts; (2) Development of multipurpose water reservoirs at the River Orljava catchment area. Both projects were designed in the mid and late 1980's but due to the war were forgotten and on halt. River Trebizat meanders between Croatia and Bosnia and Herzegovina and acquires joint management by both countries. In 2010 and 2011 SLAP has organized conferences in both countries gathering all the relevant stakeholders from representatives of local and state governments, water management companies and development agencies to the scientist and interested NGO's. The conferences gave firm scientific background of the topic including presentation of all previous studies and measurements as well as model results but presented in manner appropriate to the stakeholders. The main result of the conference was contribution to the development of joint cross-border project sent to the EU Pre-Accession funds in December 2011 with the aim to strengthen capacities of both countries and prepare larger project dealing with management of the whole Trebizat catchment area to EU structural funds once Croatia enters EU in 2013. Similar approach was taken for the Orljava catchment in the northern

  6. The inflow of polonium (210)Po from Vistula river catchments area.

    Science.gov (United States)

    Skwarzec, Bogdan; Jahnz, Anna

    2007-12-01

    The activities of polonium (210)Po in Vistula unfiltered water samples, collected from November 2002 to November 2003, were measured using the alpha spectrometry. In winter, the highest concentration of (210)Po was in Vistula river water from Torun (2.72 +/- 0.04 Bq x m(-3)) and from the Wieprz river (5.46 +/- 0.07 Bq x m(-3) [Bequerel per cubic metre]), and the lowest was in water from Nida river (0.59 +/- 0.02 Bq x m(-3)). During spring, the highest concentration of (210)Po was observed in Vistula water collected in Deblin (5.98 +/- 0.03 Bq x m(-3)) and the lowest in water from the Narew river (1.20 +/- 0.12 Bq x m(-3)). In summer, the highest concentration of (210)Po was in Nogat river water collected in Malbork (3.18 +/- 0.04 Bq x m(-3)) and the Bzura river (5.30 +/- 0.02 Bq x m(-3)), the lowest in Wieprz river (0.49 +/- 0.09 Bq x m(-3)) and Vistula river water from Kraków (1.44 +/- 0.05 Bq x m(-3)). In autumn, the highest (210)Po concentration was in Bzura river (8.93 +/- 0.03 Bq x m(-3)), the lowest in Vistula water from Grudziadz (1.51 +/- 0.04 Bq x m(-3)), and Toruń (1.89 +/- 0.05 Bq x m(-3)). The highest quantity of (210)Po was transported from Vistula catchments area to the Baltic Sea in spring and the lowest in summer. Annually, the southern Baltic Sea is enriched by about 73.7 GBq (210)Po (with Leniwka and Nogat rivers), with 71.6 GBq going to Gdańsk Bay and 2.1 GBq to Vistula Lagoon. The highest surface (210)Po runoff was observed in spring (to 1370 kBq x km(-2) x quarter(-1) for Dunajec catchment's area), the lowest in summer (for Nida catchment's area to 100 kBq x km(-2) x quarter(-1)).

  7. Assessment of Socioeconomic Vulnerability to Floods in the Bâsca Chiojdului Catchment Area

    Directory of Open Access Journals (Sweden)

    REMUS PRĂVĂLIE

    2014-12-01

    Full Text Available Hydrological risk phenomena such as floods are among the most costly natural disasters worldwide, effects consisting of socioeconomic damages and deaths. The Bâsca Chiojdului catchment area, by its morphometric and hydrographic peculiarities, is prone to generate these hydrological risk phenomena, so there is a high vulnerability in the socioeconomic elements. This paper is focused on the identification of the main socioeconomic elements vulnerable to hydrological risk phenomena such as floods, based on the assessment of their manifestation potential. Thus, following the delimitation of areas with the highest flood occurrence potential (susceptibility to floods, major socioeconomic factors existing in the basin, considering human settlements (constructions, transport infrastructure, and agricultural areas (the most important category, were superimposed. Results showed a high vulnerability for all three exposed socioeconomic elements especially in valley sectors, of which household structures were the most vulnerable, given both their importance and the high number of areas highly exposed to floods (approximately 2,500 houses and outbuildings, out of a total of about 10,250, intersect the most susceptible area to floods in the study area.

  8. ESTIMATION AND MAPPING OF EXTREME RAINFALL IN THE CATCHMENT AREA OF BATNA (ALGERIA

    Directory of Open Access Journals (Sweden)

    Guellouh SAMI

    2016-06-01

    Full Text Available Statistical estimation of rainfall associated with extreme events is of major interest for hydrologists in terms of risk prevention. Comprehending the spatial distribution of extreme rainfalls that cover the entire catchment area, the impluvium, of Batna, requires as a first step a frequency analysis of annual maximum daily rainfall time series with the application of empirical distributions, namely the GEV distribution, the Gumbel distribution and the log-normal distribution. This has allowed us to estimate the quantiles of extreme rainfall with return periods of 5, 10, 20, 50 and 100 years for ten rainfall stations. Subsequently, this has allowed us to map the quantiles matching the centennial return period using three types of interpolations.

  9. 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.

  10. Wood ash or dolomite treatment of catchment areas - effects of mercury in runoff water

    Energy Technology Data Exchange (ETDEWEB)

    Parkman, H.; Munthe, J. [Swedish Environmental Research Inst., Stockholm (Sweden)

    1996-11-01

    A future increased use of biomass as a source of energy, and the planned restoration of mineral nutrient balance in the forest soils by returning the wood ashes, has led to concern for new environmental disturbances. The objectives of the present study were to investigate if the outflow of total mercury (TotHg) and methyl mercury (MeHg) from catchment areas treated with granulated wood ash (1988, 2.2 tons/ha, `ashed area`) or dolomite (1985, 5 tons/ha, `limed area`) differed from the outflow from an untreated (reference) area, and if variations in Hg outflow were correlated with changes in the outflow of organic substances or pH. The study areas are situated in Vaermland, Sweden. Samples of run-off water were taken weekly or monthly (depending on water-flow) during on year (1993-94). The outflow of MeHg, TotHg as well as H+ and dissolved organic material (DOC) was lower from the limed area compared to the other two areas, which did not differ significantly. There was a strong covariation between concentrations of DOC and MeHg and a weaker relation between DOC and TotHg in the run-off waters. MeHg also covaried with temperature while TotHg covaried with pH and water-supply. No difference was found when comparing Hg-data from the limed area before, directly after and eight years after the liming event. 13 refs, 12 figs, 1 tab

  11. Incidence of severe diarrhoea due to Vibrio cholevae in the catchment area of six surveillance hospitals in Bangladesh

    Science.gov (United States)

    Paul, R. C.; Faruque, A. S. G.; Alam, M.; Iqbal, A.; Zaman, K.; Islam, N.; Sobhan, A.; Das, S. K.; Malek, M. A.; Qadri, F.; Cravioto, A.; Luby, S.P.

    2015-01-01

    SUMMARY Cholera is an important public health problem in Bangladesh. Interventions to prevent cholera depend on their cost-effectiveness which in turn depends on cholera incidence. Hospital-based diarrhoeal disease surveillance has been ongoing in six Bangladeshi hospitals where a systematic proportion of patients admitted with diarrhoea were enrolled and tested for Vibrio cholerae. However, incidence calculation using only hospital data underestimates the real disease burden because many ill persons seek treatment elsewhere. We conducted a healthcare utilization survey in the catchment areas of surveillance hospitals to estimate the proportion of severe diarrhoeal cases that were admitted to surveillance hospitals and estimated the population-based incidence of severe diarrhoea due to V. cholerae by combining both hospital surveillance and catchment area survey data. The estimated incidence of severe diarrhoea due to cholera ranged from 0·3 to 4·9/1000 population in the catchment area of surveillance hospitals. In children aged catchment area (18·5/100 000 population). This study provides a credible estimate of the incidence of severe diarrhoea due to cholera in Bangladesh, which can be used to assess the cost-effectiveness of cholera prevention activities. PMID:26391481

  12. Water quality assessment of the Asata River catchment area in Enugu Metropolis, Southeast Nigeria

    Science.gov (United States)

    Osinowo, Olawale Olakunle

    2016-09-01

    Hydrogeochemical mapping of the Asata River Catchment area in the Enugu metropolis, southeast Nigeria was carried out in order to assess the quality of the surface and groundwater and based on the analyses of the hydrogeochemical data, establish the level of chemical contaminations which inhibit the availability of potable water in the area. Forty (40) water samples comprising five (5) springs, nineteen (19) surface (streams/rivers) and sixteen (16) groundwater (well/borehole) samples were collected and analysed for the presence and degree of contamination of nine (9) major chemical contaminants. Hydrochemical analyses indicate that Electrical Conductivity (EC) which has a linear relationship with Total Dissolved Solid (TDS) ranges between 015 and 887 μS/cm, pH between 4.4 and 8.3, nitrate (NO3-) ranges between 40 and 130 mg/l and chloride (Cl-) between 7 and 130 mg/l. The concentrations of the dissolved chemical constituents defined the pollution trend and the rate of dispersion of contaminants. The degree of contaminants followed a simple trend, where the level of contamination of the dissolved chemical constituents is least in sampled spring water, with measured chemical constituents of EC, pH, NO3- and Cl- range from 15 to 354 μS/cm; 6.4-6.5; 4.0-70 mg/l and 8-36 mg/l, respectively. However, the value of the measured chemical constituent of EC, pH, NO3- and Cl- gradually increases down the stream in both the surface (63-354 μS/cm; 4.5-7.7; 7.1-110 mg/l; 8-41 mg/l) and groundwater (56-531 μS/cm; 4.5-7.5; 40-130 mg/l; 7-130 mg/l), respectively. Noticeable peaks in contamination levels characterised sections of the study area where human population or their activities is highest. The result of the hydrogeochemical mapping indicate that Enugu coal mine operation, the industrial activities, fertilizer applied to plants cultivated on river banks and domestic human wastes which are indiscriminately dumped along river channels are the major sources of chemical

  13. Critical Loads of Heavy Metals in a Highly Polluted Catchment Area in Egypt

    Institute of Scientific and Technical Information of China (English)

    Ahmed A. Melegy; T. Paces

    2004-01-01

    Heavy metals in different environmental compartments can be hazardous to ecosystems. Budgets of Cd, Pb and Zn in small ecosystems of the Shubra El-Kheima area in Egypt are presented. The budgets are not in steady state because they change with time. So the concentrations of the metals are a function of time. The critical loads of heavy metals to soils can be calculated from an inventory of inputs and outputs of the trace components in the catchment area. Critical time is an important parameter for critical load evaluation because it can indicate which of the heavy metals may be the most acute threat to the soils. Egyptian soil in the Shubra El-Kheima area seems to be in danger of heavy metal pollution by Zn, Cd and Pb. The calculated critical loads and their exceedances are approximate indicators of the hazards in the soil system. The critical time is a warning signal to initiate an environmental evaluation of possible pollution hazards.

  14. Determining source areas of biodegradable dissolved organic matter in two peatland catchments with different upland forest types, Minnesota, USA

    Science.gov (United States)

    Sebestyen, S. D.; Funke, M.; Cotner, J.

    2016-12-01

    Long-term studies at the Marcell Experimental Forest in Minnesota have shown that peatland catchments have distinct landscape areas (peatlands or upland mineral soils), with unique hydrological and biogeochemical processes that affect flows of water and solutes. Nonetheless, little has been known about the relative importance of source areas or forest cover types on the biodegradability of dissolved organic matter (DOM) as waters water move from bogs or uplands to outlet streams. In this study, we measured biodegradable dissolved organic carbon (BDOC) from multiple sources (upland surface and subsurface runoff, upland-peatland interfaces in laggs, and stream outlets) in two catchments having different upland forest types, deciduous or coniferous. We measured: total organic carbon (TOC), total nitrogen (TN), and dissolved organic nitrogen (DON) to calculate DOC:TN and DOC:DON; short-term (48-hour) bacterial respiration (BR); long-term (one-year), bottle incubation assays of BDOC; streamflow; and volumes of upland runoff along surface and subsurface flowpaths. We also experimented by mixing various waters to assess priming effects on BDOC concentrations and BR. The BDOC concentrations and BR were greater in upland surface runoff than in subsurface flow, laggs, or outlets, indicating that DOC in the upland surface runoff was most biodegradable. We did not observe priming effects with the mixing of any waters. In terms of catchment hydrology, most streamflow (43 to 87%) was derived from bogs, not uplands. Consequently, bogs were more important sources of biodegradable DOC. Nonetheless, there was some effect of upland cover type: BDOC concentrations and BR were greater in the outlet of the coniferous catchment than the deciduous catchment, which could be due to greater TN relative to carbon in the coniferous than in the deciduous upland catchment (C:N effects of forest cover type on the export and degradation of DOC from upland soils, despite the overall importance of

  15. Hydrological modelling in a drinking water catchment area as a means of evaluating pathogen risk reduction

    Science.gov (United States)

    Bergion, Viktor; Sokolova, Ekaterina; Åström, Johan; Lindhe, Andreas; Sörén, Kaisa; Rosén, Lars

    2017-01-01

    Waterborne outbreaks of gastrointestinal diseases are of great concern to drinking water producers and can give rise to substantial costs to the society. The World Health Organisation promotes an approach where the emphasis is on mitigating risks close to the contamination source. In order to handle microbial risks efficiently, there is a need for systematic risk management. In this paper we present a framework for microbial risk management of drinking water systems. The framework incorporates cost-benefit analysis as a decision support method. The hydrological Soil and Water Assessment Tool (SWAT) model, which was set up for the Stäket catchment area in Sweden, was used to simulate the effects of four different mitigation measures on microbial concentrations. The modelling results showed that the two mitigation measures that resulted in a significant (p treatment (by one Log10 unit) at the wastewater treatment plants. The mitigation measure with a vegetative filter strip linked to grazing areas resulted in a significant reduction of Cryptosporidium spp., but not of E. coli concentrations. The mitigation measure with enhancing the removal efficiency of all on-site wastewater treatment systems (total removal of 2 Log10 units) did not achieve any significant reduction of E. coli or Cryptosporidium spp. concentrations. The SWAT model was useful when characterising the effect of different mitigation measures on microbial concentrations. Hydrological modelling implemented within an appropriate risk management framework is a key decision support element as it identifies the most efficient alternative for microbial risk reduction.

  16. A Regional Earth System Perspective on the Water Budget over the Mediterranean Catchment Area.

    Science.gov (United States)

    Dell'Aquila, A.; Calmanti, S.; Carillo, A.; Pisacane, G.; Ruti, Pm; Sannino, G.; Struglia, Mv; Artale, V.

    2010-09-01

    We present a quantitative analysis of the water content in the atmosphere, soil and ocean over the Mediterreanean catchment area. The Regional Earth System developed by ENEA-ICTP, the PROTHEUS system, is an optimal modelling tool for this purpose as it explicitly accounts for the various components of the hydrological cycle and their interactions. In particular, the PROTHEUS system provides a reliable description of high resolution sea surface temperature and wind fields over the ocean, in close agreement to observations thereby providing a reliable description of air-seas fluxes (particularly the latent heat flux). In this analysis, all the terms of hydrological cycle are computed for different simulations performed by an implemented version of PROTHEUS with interactive river runoff. To assess model performances we show 1951-2050 simulation, driven at the lateral boundaries by ECHAM5-MPIOM global simulation included in the IPCC-AR4, compared against control simulation driven by ERA40, the global drivers themselves and observational datasets. The modelling tools presented in this work, developed in the framework of CIRCE EU Project RL2 will also contribute to the Med-CORDEX activities.

  17. Species identification and selection to develop agroforestry at Lake Toba Catchment Area (LTCA

    Directory of Open Access Journals (Sweden)

    NURHENI WIJAYANTO

    2011-01-01

    Full Text Available Wijayanto N (2011 Species identification and selection to develop agroforestry at Lake Toba Catchment Area (LTCA. Biodiversitas 12: 52-58. In order to improve land productivity surrounding the LTCA, the existing ITTO project tries to establish agroforestry system. The system will be designed to meet consideration of both sides. on one side is to generate the people awareness of the forest and land rehabilitation, and on the other side is to support the poverty reduction. The aims of this research are: species identification and selection to develop agroforestry at LTCA. Data collecting was carried out with: interview, group discussion, field observation, divining manual study, and PRA. The diversity of the available crop kind shows the number of choices to be developed by the farmer. The farmers generally have the economic objective to develop agroforestry, including increase in net income, risk reduction, increase in environmental service, and the wealth and savings accumulation. Various types of agricultural crops, plantations and forest trees were found in LTCA. They can be the basis for building a wide variety of agroforestry systems.

  18. Evaluation and assessment of water quality in Likangala River and its catchment area

    Science.gov (United States)

    Chidya, R. C. G.; Sajidu, S. M. I.; Mwatseteza, J. F.; Masamba, W. R. L.

    Likangala is one of the perennial rivers in Malawi that flow into a closed Lake Chilwa, a designated wetland ratified by Ramsar Convention in 1997. Earlier work conducted on this river revealed considerable social-economic activities at riverbanks resulting in indiscriminate disposal of wastes. This study intended to evaluate water quality in Likangala River and its catchment area. Water samples were collected thrice (dry, early rainy and mid rainy seasons) and tested for major physico-chemical and microbiological parameters. The EC, pH, and selected ions ( NO3-, PO43-, Na +, K +, Mg 2+, and Ca 2+) were analysed in soil samples obtained in crop fields along the river banks. Elevated EC levels (>1035.00 μS/cm) were measured during mid rainy season at site S15 (Zomba Sewage Works), near and in the lake. Most of the water samples (86%, n = 28) registered phosphate levels above 1.50 mg/L during mid rainy season with a maximum value (10.70 ± 0.01 mg/L) at site S15. Lower amounts (control of water, land use and waste management in order to prevent escalation of the effects.

  19. Modeling of debris flow depositional patterns according to the catchment and sediment source area characteristics

    OpenAIRE

    2015-01-01

    A method to predict the most probable flow rheology in Alpine debris flows is presented. The methods classifies outcropping rock masses in catchments on the basis of the type of resulting unconsolidated deposits. The grain size distribution of the debris material and the depositional style of past debris flow events are related to the dominant flow processes: viscoplastic and frictional/collisional. Three catchments in the upper Susa Valley (Western Alps), characterized by different lithologi...

  20. Prevalence and Correlates of Psychological Distress and Psychiatric Disorders in Asylum Seekers and Refugees Resettled in an Italian Catchment Area.

    Science.gov (United States)

    Nosè, Michela; Turrini, Giulia; Imoli, Maria; Ballette, Francesca; Ostuzzi, Giovanni; Cucchi, Francesca; Padoan, Chiara; Ruggeri, Mirella; Barbui, Corrado

    2017-07-20

    In recent years there has been a progressive rise in the number of asylum seekers and refugees displaced from their country of origin, with significant social, economic, humanitarian and public health implications. The aim of this study is to describe the frequency and correlates of psychological distress and psychiatric disorders in asylum seekers and refugees resettled in an Italian catchment area. In the catchment area of Verona, all male asylum seekers and refugees aged 18 or above included in the Italian protection system for asylum seekers and refugees during a period of 1 year were screened for psychological distress and psychiatric disorders using validated questionnaires. During the study period, 109 asylum seekers or refugees were recruited. The frequency of traumatic events experienced was very high. More than one-third of the participants (36%) showed clinically relevant psychological distress, and one-fourth (25%), met the criteria for a psychiatric diagnosis, mainly PTSD and depressive disorders. In multivariate analyses, time after departure, length of stay in the host country and number of traumatic events were independent factors associated with psychological distress and psychiatric disorders. In an unselected sample of male asylum seekers and refugees, after around 1 year of resettlement in an Italian catchment area, the frequency of psychological distress and psychiatric disorders was substantial and clinically relevant. Health care systems should include a mental health component to recognise and effectively treat mental health conditions.

  1. Incidence of severe diarrhoea due to Vibrio cholerae in the catchment area of six surveillance hospitals in Bangladesh.

    Science.gov (United States)

    Paul, R C; Faruque, A S G; Alam, M; Iqbal, A; Zaman, K; Islam, N; Sobhan, A; DAS, S K; Malek, M A; Qadri, F; Cravioto, A; Luby, S P

    2016-04-01

    Cholera is an important public health problem in Bangladesh. Interventions to prevent cholera depend on their cost-effectiveness which in turn depends on cholera incidence. Hospital-based diarrhoeal disease surveillance has been ongoing in six Bangladeshi hospitals where a systematic proportion of patients admitted with diarrhoea were enrolled and tested for Vibrio cholerae. However, incidence calculation using only hospital data underestimates the real disease burden because many ill persons seek treatment elsewhere. We conducted a healthcare utilization survey in the catchment areas of surveillance hospitals to estimate the proportion of severe diarrhoeal cases that were admitted to surveillance hospitals and estimated the population-based incidence of severe diarrhoea due to V. cholerae by combining both hospital surveillance and catchment area survey data. The estimated incidence of severe diarrhoea due to cholera ranged from 0.3 to 4.9/1000 population in the catchment area of surveillance hospitals. In children aged cholera in Bangladesh, which can be used to assess the cost-effectiveness of cholera prevention activities.

  2. Satellite imagery technology in public health: analysis of site catchment areas for assessment of poliovirus circulation in Nigeria and Niger.

    Science.gov (United States)

    Takane, Marina; Yabe, Shizu; Tateshita, Yumiko; Kobayashi, Yusuke; Hino, Akihiko; Isono, Kazuo; Okayasu, Hiromasa; Diop, Ousmane M; Tadono, Takeo

    2016-11-21

    Environmental surveillance supplements the surveillance of acute flaccid paralysis by monitoring wastewater for poliovirus circulation. Building on previous work, we analysed wastewater flow to optimise selection and placement of sampling sites with higher digital surface model (DSM) resolution. The newly developed 5-m mesh DSM from the panchromatic, remote-sensing instruments for stereo mapping on-board the Japanese advanced land observing satellite was used to estimate catchment areas and flow of sewage water based on terrain topography. Optimal sampling sites for environmental surveillance were identified to maximise sensitivity to poliovirus circulation. Population data were overlaid to prioritise selection of catchment areas with dense populations. The results for Kano City, Nigeria were compared with an analysis based on existing 30- and 90-m mesh digital elevation model (DEM). Analysis based on 5-m mesh DSM was also conducted for three cities in Niger to prioritise the selection of new sites. The analysis demonstrated the feasibility of using DSMs to estimate catchment areas and population size for programme planning and outbreak response with respect to polio. Alternative sampling points in Kano City that would cover a greater population size have been identified and potential sampling sites in Niger are proposed. Comparison with lower-resolution DEMs suggests that the use of a 5-m mesh DSMs would be useful where the terrain is flat or includes small-scale topographic changes not captured by 30-m data searches.

  3. The potential benefits of herbicide regulation: a cautionary note for the Great Barrier Reef catchment area.

    Science.gov (United States)

    Davis, A M; Lewis, S E; Brodie, J E; Benson, Ash

    2014-08-15

    Industry transitions away from traditional photosystem II inhibiting (PSII) herbicides towards an 'alternative' herbicide suite are now widely advocated as a key component of improved environmental outcomes for Australia's Great Barrier Reef and improved environmental stewardship on the part of the Queensland sugar industry. A systematic desktop risk analysis found that based on current farming practices, traditional PSII herbicides can pose significant environmental risks. Several of the 'alternatives' that can directly fill a specific pre-emergent ('soil residual') weed control function similar to regulated PSII herbicides also, however, presented a similar environmental risk profile, regardless of farming systems and bio-climatic zones being considered. Several alternatives with a pre-emergent residual function as well as alternative post-emergent (contact or 'knockdown') herbicides were, predicted to pose lower environmental risks than the regulated PSII herbicides to most trophic levels, although environmental risks could still be present. While several herbicides may well be viable alternatives in terms of weed control, they can still present equal or possibly higher risks to the environment. Imposing additional regulations (or even de-registrations) on particular herbicides could result in marginal, and possibly perverse environmental impacts in the long term, if usage shifts to alternative herbicides with similar risk profiles. Regardless of any regulatory efforts, improved environmental sustainability outcomes in pesticide practices within the Great Barrier Reef catchment area will hinge primarily on the continuing adoption of integrated, strategic pest management systems and technologies applied to both traditional and 'alternative' herbicides. One of the emerging policy challenges is ensuring the requisite technical and extension support for cane growers to ensure effective adoption of rapidly evolving farming system technologies, in a very dynamic and

  4. Modeling of debris flow depositional patterns according to the catchments and sediment source areas characteristics

    Science.gov (United States)

    Tiranti, Davide; Deangeli, Chiara

    2015-03-01

    A method to predict the most probable flow rheology in Alpine debris flows is presented. The methods classifies outcropping rock masses in catchments on the basis of the type of resulting unconsolidated deposits. The grain size distribution of the debris material and the depositional style of past debris flow events are related to the dominant flow processes: viscoplastic and frictional/collisional. Three catchments in the upper Susa Valley (Western Alps), characterized by different lithologies, were selected for numerical analysis carried out with a Cellular Automata code with viscoplastic and frictional/collisional rheologies. The obtained numerical results are in good agreement with in site evidences in terms of depositional patterns, confirming the possibility of choosing the rheology of the debris flow based on the source material within the catchment.

  5. Watershed Modeling with ArcSWAT and SUFI2 In Cisadane Catchment Area: Calibration and Validation of River Flow Prediction

    Directory of Open Access Journals (Sweden)

    Iwan Ridwansyah

    2014-04-01

    Full Text Available Increasing of natural resources utilization as a result of population growth and economic development has caused severe damage on the watershed. The impacts of natural disasters such as floods, landslides and droughts become more frequent. Cisadane Catchment Area is one of 108 priority watershed in Indonesia. SWAT is currently applied world wide and considered as a versatile model that can be used to integrate multiple environmental processes, which support more effective watershed management and the development of better informed policy decision. The objective of this study is to examine the applicability of SWAT model for modeling mountainous catchments, focusing on Cisadane catchment Area in west Java Province, Indonesia. The SWAT model simulation was done for the periods of 2005 – 2010 while it used landuse information in 2009. Methods of Sequential Uncertainty Fitting ver. 2 (SUFI2 and combine with manual calibration were used in this study to calibrate a rainfall-runoff. The Calibration is done on 2007 and the validation on 2009, the R2 and Nash Sutchliffe Efficiency (NSE of the calibration were 0.71 and 0.72 respectively and the validation are 0.708 and 0.7 respectively. The monthly average of surface runoff and total water yield from the simulation were 27.7 mm and 2718.4 mm respectively. This study showed SWAT model can be a potential monitoring tool especially for watersheds in Cisadane Catchment Area or in the tropical regions. The model can be used for another purpose, especially in watershed management.

  6. Spatially distributed rockfall activity inferred from talus deposits and corresponding rockwall areas in the Gradenbach catchment (Schober Mountains, Austria)

    Science.gov (United States)

    Götz, Joachim; Buckel, Johannes; Heckmann, Tobias

    2013-04-01

    The analysis of alpine sediment cascades requires the identification, differentiation and quantification of sediment sources, storages, and transport processes. This study deals with the origin of alpine sediment transfer and relates primary talus deposits to corresponding rockwall source areas within the Gradenbach catchment (Schober Mountains, Austrian Alps). Sediment storage landforms are based on a detailed geomorphological map of the catchment which was generated to analyse the sediment transfer system. Mapping was mainly performed in the field and supplemented by post-mapping analysis using LIDAR data and digital orthophotos. A fundamental part of the mapping procedure was to capture additional landform-based information with respect to morphometry, activity and connectivity. The applied procedure provides a detailed inventory of sediment storage landforms including additional information on surface characteristics, dominant and secondary erosion and deposition processes, process activity and sediment storage coupling. We develop the working hypothesis that the present-day surface area ratio between rockfall talus (area as a proxy for volume, backed by geophysical analysis of selected talus cones) and corresponding rockwall source area is a measure of rockfall activity since deglaciation; large talus cones derived from small rockwall catchments indicate high activity, while low activity can be inferred where rockfall from large rock faces has created only small deposits. The surface area ratio of talus and corresponding rockwalls is analysed using a landform-based and a process-based approach. For the landform-based approach, we designed a GIS procedure which derives the (hydrological) catchment area of the contact lines of talus and rockwall landforms in the geomorphological map. The process-based approach simulates rockfall trajectories from steep (>45°) portions of a DEM generated by a random-walk rockfall model. By back-tracing those trajectories that

  7. Effect of Catchment Area Activities on the Physico – Chemical Characteristics of Water of Upper Lake, Bhopal with Special Reference to Nitrate and Phosphate Concentration

    Directory of Open Access Journals (Sweden)

    Ranjana Talwar

    2014-04-01

    Full Text Available With the tremendous influx of people and consequent urban development, increased anthropogenic activities in the catchment, inflow of untreated sewage, nutrients and pesticides from urban and rural areas, the water quality of Upper Lake, Bhopal has deteriorated significantly. An attempt has been made to study various physico – chemical parameters, specifically nitrates and phosphates of five different sampling sites of Upper Lake and to study the effect of catchment area activities on these sites.

  8. Large Scale Groundwater Flow Model for Ho Chi Minh City and its Catchment Area, Southern Vietnam

    Science.gov (United States)

    Sigrist, M.; Tokunaga, T.; Takizawa, S.

    2005-12-01

    Ho Chi Minh City (HCMC) has become a fast growing city in recent decades and is still growing at a high pace. The water demand for more than 7 million people has increased tremendously, too. Beside surface water, groundwater is used in big amounts to satisfy the need of water. By now, more than 200,000 wells have been developed with very little control. To investigate the sustainability of the water abstraction, a model had been built for the HCMC area and its surrounding. On the catchment scale (around 24,000km2); however, many questions have remained unsolved. In this study, we first gathered and complied geological and hydrogeological information as well as data on groundwater quality to get an idea on regional groundwater flow pattern and problems related to the temporal change of the groundwater situation. Two problems have been depicted by this study. One is the construction of a water reservoir upstream of the Saigon River. This construction has probably changed the water table of the unconfined aquifer, and hence, has significantly changed the properties of soils in some areas. The other problem is the distribution of salty groundwater. Despite the distance of more than 40km from the seashore, groundwater from some wells in and around HCMC shows high concentrations of chloride. Several wells started to produce non-potable water. The chloride concentrations show a complicated and patchy distribution below HCMC, suggesting the possibility of the remnant saltwater at the time of sediment deposition. On the other hand, seawater invades along the streams far beyond HCMC during the dry season and this might be one of the possible sources of salty groundwater by vertical infiltration. A large-scale geological model was constructed and transformed into a hydrogeological model to better understand and quantify the groundwater flow system and the origin of saltwater. Based on the constructed model and numerical calculation, we discuss the influence of reservoir

  9. Seasonal variability of suspended sediment transport in the Seine river catchment area (France)

    Science.gov (United States)

    Franke, Christine; Baati, Selma; Ayrault, Sophie; Bonte, Philippe; Evrard, Olivier; Kissel, Catherine

    2010-05-01

    This study consists in an innovative application of environmental physico-chemical techniques on fluvial sediments with the aim to trace the seasonal changes in suspended sediment transport of the complex Seine river catchment area in northern France. The aim of this project is to develop a detailed understanding for the discrimination of naturally triggered and anthropogenic induced processes and their temporal changes with weather conditions. With a focus on the heavy metal fraction, we determine the regional distribution of the suspended material and search for environmental fingerprints demonstrating the influence of fluvial transport mechanisms, changes in concentration related to discharge variations or different sediment sources, and in-situ alteration caused by variations in the geochemical conditions (oxy-redox, pH, Eh, etc.). To achieve these goals, we apply a combination of straightforward rock magnetic hysteresis measurements (performed using an AGM2900 at the LSCE) and advanced scanning electron microscopy analyses (SEM). This interdisciplinary approach allows refining the detailed analysis of sediment trap samples, originating from Tessier et al. (2003), as recently shown by Franke et al. (2009). In our preliminary results, we observe a general increase in magnetic concentrations from summer to winter conditions, coupled with a magneto-mineralogic change to rather reduced metallic mineral phases. However, each riversection of the Seine system shows its specific trend line depending on the regional initial input, weathering conditions, drainage area and potential pollution sources. A systematic analysis of the detailed results will allow highlighting the climatic/seasonal influence on the metallic particle assembly. Keywords: Seine river system, environmental magnetism, suspended particulate matter, anthropogenic and natural input, magnetic hysteresis, scanning electron microscopy (SEM),, heavy metal pollution, seasonal variability References: Franke

  10. Analysis on radiocesium concentration in rivers that have catchment areas affected by the fallout from Fukushima Daiichi Nuclear Power Plant

    Science.gov (United States)

    Taniguchi, Keisuke; Yoshimura, Kazuya; Sakaguchi, Aya; Yamamoto, Masayoshi; Onda, Yuichi

    2014-05-01

    Due to Fukushima Daiichi Nuclear Power Plant accident, radioactive materials including Cs-134 and Cs-137 were widely distributed in surrounded area. The radiocesiums have been transported in river networks. This study showed the monitoring results of radiocesium concentration in river waters and suspended sediments in Abukuma river basin and smaller coastal river catchments. The monitoring started at 6 sites from June 2011. Subsequently, additional 24 monitoring sites were installed between October 2012 and January 2013. Flow and turbidity (for calculation of suspended sediment concentration) were measured at each site, while suspended sediments and river water were collected every one or half month to measure Cs-134 and Cs-137 activity concentrations by gamma spectrometry. Activity concentrations of Cs-134 and Cs- 137 on suspended sediments were generally decreasing at all sites. The decreasing rate changed lower at about one year later from the accident. Activity concentration in river waters also showed the same tendency although there are only few data within 1 year from the accident. Activity concentrations measured at the same day are proportional to the mean catchment inventory. Therefore, the activity concentration can be normalized by the mean catchment inventory. The normalized activity can be fitted to following double exponential function: [At] = 1.551 exp (-5.265t) + 0.069 exp (-0.266 t), where t [year] is the time from the accident. There is no time evolution of Kd between suspended sediments and river water. Instead, Kd was varied spatially. Although the reason of the spatial variation is not clear for now, geology of the catchment (i.e. mineral composition of suspended particles) seems to relate to the variation.

  11. Contextual and individual influences on diabetes and heart disease in Havana primary care catchment areas.

    Science.gov (United States)

    Díaz-Perera, Georgia; Bacallao, Jorge; Alemañy, Eduardo

    2013-04-01

    A population health profile is a cumulative product of socioenvironmental and political factors that create the contexts in which health problems arise, as well as opportunities and barriers to addressing them. Research on context has focused on demonstrating its effects, direct or indirect, on health indicators, but has made few incursions into assessing its role as a mediator of other factors. While individual risk factors for chronic diseases are well known, the same cannot be said for the complex of contextual factors operating at various levels and over the lifespan. Estimate relative influences by contextual versus individual factors as determinants of diabetes type 2 and heart disease. A cross-sectional study was carried out in populations served by 12 family doctor-and-nurse practices in Havana, in 840 families selected by simple random sampling, 70 per practice. Principal components analysis was used, as well as contextual logistic regression models with a nested model strategy, whose fit was meant to estimate the relative contributions of contextual compared to individual risk factors for diabetes and heart disease. Context was described and analyzed at two levels: that of the family or household and that of the catchment area served by a family doctor-and-nurse practice (geographically defined as a neighborhood). For diabetes, the contextual effect of neighborhood was modified when household effect was removed; that is, the effect of neighborhood was indirect and mediated by household. Individual coefficients were practically invariant; the principal effect of household changed noticeably on removal of individual effects, while age maintained its effect without variation. For heart disease, the effect of neighborhood was slightly modified when household effect was controlled for. Individual coefficients showed little change. There was an important direct effect of household on risk of heart disease. Age and high blood pressure coefficients hardly varied

  12. Early Signs of Atherogenesis in Adolescents in a Havana Family Medicine Catchment Area.

    Science.gov (United States)

    Valdés, Wendy; Díaz-Perera, Georgia; Espinosa, Tania M

    2015-10-01

    INTRODUCTION Atherosclerosis is the common underlying cause of cardiovascular diseases; the leading cause of morbidity and mortality globally. It is a major contributor to disability and poorer quality of life and is costly to health systems, individuals, families and society. Early signs of atherogenesis are manifestations of atherosclerosis and known atherogenic risk factors occurring at young ages and detectable by health professionals. Early detection of such signs in children and adolescents enables actions to prevent short- and long-term complications. OBJECTIVE Detect early signs of atherogenesis in adolescents in Family Doctor-and-Nurse Office No. 13 of the Raúl Gómez García Polyclinic in Havana's 10 de Octubre Municipality. METHODS An observational, cross-sectional descriptive study was conducted: the universe consisted of 110 adolescents and, once exclusion criteria were applied, the sample was made up of 96 adolescents in the office's geographical catchment area. Variables included sociodemographic data; measurements from physical and anthropometric examinations (weight, height, body mass index, waist circumference, blood pressure, presence of acanthosis nigricans); maternal history of diabetes mellitus and hypertension, smoking during pregnancy; birth weight and duration of exclusive breastfeeding; lifestyle (physical activity, dietary habits by frequency of consumption of fruits and vegetables, salt intake, and smoking); and a history of atherogenic risk factors and atherosclerotic diseases (hypertension, diabetes mellitus, heart disease, cerebrovascular disease, peripheral arterial disease and chronic kidney disease) in adolescents and their families. The number of early signs of atherogenesis was determined. Descriptive statistics and a chi-square test, with significance threshold set at p = 0.05, were used to examine differences by sex and age. RESULTS A total of 62.5% of participating adolescents were female and the same percent of the total

  13. Typology of potential high contribution areas in the sediment budget in the Upper Guil Catchment (Queyras, French Alps)

    Science.gov (United States)

    Lissak, Candide; Fort, Monique; Fassetta, Gilles Arnaud; Viel, Vincent; Carlier, Benoit

    2015-04-01

    In mountainous areas, especially in large river catchments with torrential tributaries, the production and sediment transport significantly increase flood impacts in the valley bottoms. For a better understanding of Alpine river catchments considered as complex systems, we focused our research on the Guil River catchment (Queyras, Southern French Alps - 317km²). This catchment is prone to catastrophic summer floods (June 1957 (> R.I. 100 yr), June 2000 (R.I. 30 yr)...) characterized by considerable sediment transport from tributaries to downvalley, very much facilitated by strong hillslope-channel connectivity (≈12,000 m3 volume of sediment aggraded during the June 2000 flood event). During the last flood events, several infrastructures and buildings were seriously damaged. Most of them were located at confluences and, at specific reaches such as canyon reaches constrained by infrastructures. For risk mitigation some protection equipments were built after the 1957 event, but most of them are now poorly maintained and might be less effective in case of flood event. In the frame of SAMCO (ANR 12 SENV-0004) project designed for mountain hazard mitigation in a context of Climate Change, one objective is to understand the hydro-geomorphological functioning of Alpine catchments for a sustainable management of sediment yield, transfer and deposition. Part of our study is aimed at a better assessment of sediment transfers, especially on adjacent sediment supply (i.e. from hillslope to channel, and from tributaries to the trunk river) for a better management of sediment fluxes in the frame of the local "River Scheme". For this reason, we decided to establish a sediment budget of the Guil River catchment, with a quantitative assessment and a spatial analysis of erosion, transport, and deposition processes. The initial phase of our study consists in identifying contributive, erosion and deposition areas with a twofold approach: (i) assessment of longitudinal sedimentary

  14. THE FIRST PLAN FOR WATER RESOURCES MANAGEMENT OF SOMEȘ-TISA CATCHMENT AREA

    Directory of Open Access Journals (Sweden)

    SOFRONIE C.

    2014-03-01

    Full Text Available With time, after Romania’s accession to the E.U., the national legislation adhered to the Water Framework Directive. In the study we present the Someş and Tisa river catchments management and development plans, from the beginnings till today. We also conclude that the ecological and chemical state for the water bodies in agreement with the Water Framework Directive represents the main challenge for the future of these waters.

  15. Developing a geological 3D model for the Tanour and Rasoun spring catchment area using ArcGIS and GOCAD

    Science.gov (United States)

    Hamdan, Ibraheem; Benhsinat, Mohamed; Wagner, Bianca; Sauter, Martin

    2016-04-01

    Key words: Karst, 3D model, GOCAD, ArcGIS, Jordan. Tanour and Rasoun karst springs (around 75 km northwest of the capital city of Amman in Jordan) are used as main local water supply for the surrounding villages. Carbonate rocks are the predominant rock type in the study area (Upper Cretaceous age). The karstification degree is moderate to high, with the availability of different karst features like dolines, caves, dry valleys, and highly fractured rocks. During the last years, the water supply from these springs had to be disconnected for several times due to microbial contamination and waste water pollution from local olive oil mills. For better understanding of the geological and the hydrogeological setting of the study area, in addition to the delineation of the groundwater catchment area for Tanour and Rasoun springs, a geological 3D model of the main geological formations within the study area was established using ArcGIS and GOCAD. The model is based on geological maps and well data; it was established for seven geological layers that act as prominent aquifers and aquicludes. ArcGIS software was used for data preparation, processing and interpolation of varying thickness, while GOCAD used for geometrical modeling steps. After the completion of the first modeling steps, major faults are included. Then the subsurface catchments will be delineated and compared with the superficial watersheds. The model still under development and open for further development.

  16. Hyporheic flow pattern based on the coupling of regional and stream scales: Case of Krycklan Catchment area

    Science.gov (United States)

    Mojarrad, Morteza; Wörman, Anders; Riml, Joakim

    2016-04-01

    Water resources intense development within the past century has had an enormous impact on hydrological systems especially on rivers and groundwater resources. A river basin is a flow system involving the interaction between surface water and groundwater. This interaction occurs in terrestrial and coastal zone and even in arid and semi-arid areas, where surface water overlie on a permeable sediment. A key zone for the interaction between surface water and groundwater is the hyporheic zone, which forms by stream water that in- and exfiltrating in the permeable sediments surrounding the river corridor. Groundwater and hyporheic flows arise due to different range of topographical scales and their relative importance is investigated in this study. Krycklan is a well-monitored research catchment in which the data collection for more than 90 years has comprised hydrology, biochemistry, and aquatic ecology. The catchment is located in a boreal area of northern Sweden. The head-water streams begin in mountainous area and fall to the Baltic Sea near the city of Umea. In this paper, COMSOL Multi-physics simulation software has been used to model the subsurface flow of the whole Krycklan catchment in order to reach a comprehensive understanding of large-scale groundwater circulation and its impact of the stream hyporheic flows. The model statement is based on the 3D Laplace equation, which has been applied independently on two ranges of topographical scales to obtain a superimposed solution. Steady state simulation has been done based on the simplified assumption of constant boundary conditions of the groundwater surface and otherwise non-flow boundaries. The hydraulic head of the groundwater surface was taken as the topography, which apply as an approximation in wet climate with shallow soil layers. The results demonstrated how the ratio of the topographical amplitudes on different scales affect the size (depth) and fragmentation of the hyporheic zone. "Fragmentation" was

  17. Integration of remote sensing and GIS in monitoring the dynamics of land cover in Oroba-Kibos catchment area, Kenya

    Institute of Scientific and Technical Information of China (English)

    Were KO; Owenga PO; Wagate PN; Orlale R

    2011-01-01

    Land cover in Kenya is in a state of flux at different spatial and temporal scales.This compromises environmental integrity and socioeconomic stability of the population hence increasing their vulnerability to the externalities of environmental change.The Oroba-Kibos catchment area in western Kenya is one locality where rapid land use changes have taken place over the last 30 years.The shrubs,swamps,natural forests and other critical ecosystems have been converted on the altar of agriculture,human settlement,fuel wood and timber.This paper presents the results ora study that aimed at providing spatially-explicit information for effective remedial response through (a) Mapping the land cover; (b) Identifying the spatial distribution of land cover changes; (c) Determining the nature,rates and magnitude of the land cover changes,and; (d) Establishing the drivers of land use leading to land cover changes in Oroba-Kibos catchment area.Bi-temporal Landsat TM imagery,field observation,household survey and ancillary data were obtained.Per-field classification of the Landsat TM imagery was performed in a GIS and the resultant land cover maps assessed using the field observation data.Post-classification comparison of the maps was then done to detect changes in land cover that had occurred between 1994 and 2008.SPSS was used to analyze the household survey data and attribute the detected land cover changes to their causes.The findings showed that 9 broad classes characterize the catchment area including the natural forests,swamps,natural water bodies,woodlands,shrublands,built-up lands,grasslands,bare lands and croplands.Croplands are dominant and accounted for about 65% (57122 ha) of the total land in 1994,which increased at the rate of 0.89% to 73% (64772 ha) in 2008,while natural water bodies has the least spatial coverage accounting for about 0.6% (561 ha) of the total land in 1994,which diminished at the rate of 3.57% to 0.3% (260 ha) in 2008.Climate,altitude,access and

  18. Modeling and evaluation of compliance to water quality regulations in bathing areas on the Daoulas catchment and estuary (France).

    Science.gov (United States)

    Bougeard, M; Le Saux, J C; Jouan, M; Durand, G; Pommepuy, M

    2010-01-01

    The microbiological quality of waters in estuaries determines their acceptability for recreational uses. Microbiological contamination often results from urban wastewater discharges or non-point source pollution (manure spreading), and can cause bathing zones to be closed. European regulations (EC/7/2006) have proposed standards (500 E. coli/100 ml) for the acceptability areas for bathing. In this study, two models were associated to simulate contamination: SWAT on a catchment and MARS 2D in the downstream estuary. After river flow calibration and validation, two scenarios were simulated in SWAT, and E. coli fluxes obtained at the main outlet of the catchment were then introduced into MARS 2D to follow E. coli concentrations in the estuary. An annual evaluation of compliance to bathing area water quality standards was then calculated, linked with daily rainfall classes. Water quality in the estuary was below the standard on 13 days, including 5 days with rainfall superior to 10 mm, due to faecal contamination from soil leaching by rain, and 5 days with rainfall ranging from 0.1 to 5 mm/day, due to the high frequency of this level of rainfall. To conclude, this study allowed us to demonstrate the efficiency of models to gain a better understanding on water quality degradation factors.

  19. Organochlorine pesticides (OCPs) in the Indus River catchment area, Pakistan: Status, soil-air exchange and black carbon mediated distribution.

    Science.gov (United States)

    Bajwa, Anam; Ali, Usman; Mahmood, Adeel; Chaudhry, Muhammad Jamshed Iqbal; Syed, Jabir Hussain; Li, Jun; Zhang, Gan; Jones, Kevin C; Malik, Riffat Naseem

    2016-06-01

    Organochlorine pesticides (OCPs) were investigated in passive air and soil samples from the catchment area of the Indus River, Pakistan. ∑15OCPs ranged between 0.68 and 13.47 ng g(-1) in soil and 375.1-1975 pg m-(3) in air. HCHs and DDTs were more prevalent in soil and air compartments. Composition profile indicated that β-HCH and p,p'-DDE were the dominant of all metabolites among HCHs and DDTs respectively. Moreover, fBC and fTOC were assessed and evaluated their potential role in the distribution status of OCPs. The fTOC and fBC ranged between 0.77 and 2.43 and 0.04-0.30% respectively in soil. Regression analysis showed the strong influence of fBC than fTOC on the distribution of OCPs in the Indus River catchment area soil. Equilibrium status was observed for β-HCH, δ-HCH, p,p'-DDD, o,p'-DDT, TC, HCB and Heptachlor with ff ranged between 0.3 and 0.59 while assessing the soil-air exchange of OCPs.

  20. Probabilistic Risk Assessment in Medium Scale for Rainfall-Induced Earthflows: Catakli Catchment Area (Cayeli, Rize, Turkey

    Directory of Open Access Journals (Sweden)

    H. A. Nefeslioglu

    2011-01-01

    Full Text Available The aim of the present study is to introduce a probabilistic approach to determine the components of the risk evaluation for rainfall-induced earthflows in medium scale. The Catakli catchment area (Cayeli, Rize, Turkey was selected as the application site of this study. The investigations were performed in four different stages: (i evaluation of the conditioning factors, (ii calculation of the probability of spatial occurrence, (iii calculation of the probability of the temporal occurrence, and (iv evaluation of the consequent risk. For the purpose, some basic concepts such as “Risk Cube”, “Risk Plane”, and “Risk Vector” were defined. Additionally, in order to assign the vulnerability to the terrain units being studied in medium scale, a new more robust and more objective equation was proposed. As a result, considering the concrete type of roads in the catchment area, the economic risks were estimated as 3.6×106€—in case the failures occur on the terrain units including element at risk, and 12.3×106€—in case the risks arise from surrounding terrain units. The risk assessments performed in medium scale considering the technique proposed in the present study will supply substantial economic contributions to the mitigation planning studies in the region.

  1. Groundwater Impacts on Urban Surface Water Quality in the Lowland Polder Catchments of the Amsterdam City Area

    Science.gov (United States)

    Rozemeijer, J.; Yu, L.; Van Breukelen, B. M.; Broers, H. P.

    2015-12-01

    Surface water quality in the Amsterdam area is suffering from high nutrient levels. The sources and transport mechanisms of these nutrients are unclear due to the complex hydrology of the highly manipulated urban and sub-urban polder catchments. This study aimed at identifying the impact of groundwater on surface water quality in the polder catchments of the greater Amsterdam city area. Therefore, we exploited the dense groundwater and surface water monitoring networks to explain spatial patterns in surface water chemistry and their relations with landscape characteristics and groundwater impact. We selected and statistically analyzed 23 variables for 144 polders, covering a total area of 700 km2. Our dataset includes concentrations of total-N, total-P, ammonium, nitrate, bicarbonate, sulfate, calcium, and chloride in surface water and groundwater, seepage rate, elevation, paved area percentage, surface water area percentage, and soil type (calcite, humus and clay percentages). Our results show that nutrient levels in groundwater were generally much higher than in surface water and often exceeded the surface water Environmental Quality Standards (EQSs). This indicates that groundwater is a large potential source of nutrients in surface water. High correlations (R2 up to 0.88) between solutes in both water compartments and close similarities in their spatial patterns confirmed the large impact of groundwater on surface water quality. Groundwater appeared to be a major source of chloride, bicarbonate and calcium in surface water and for N and P, leading to exceeding of EQSs in surface waters. In dry periods, the artificial redistribution of excess seepage water from deep polders to supply water to infiltrating polders further distributes the N and P loads delivered by groundwater over the area.

  2. Carbon (δ13C) and Nitrogen (δ15N) Stable Isotope Signatures in Bat Fur Indicate Swarming Sites Have Catchment Areas for Bats from Different Summering Areas.

    Science.gov (United States)

    Segers, Jordi L; Broders, Hugh G

    2015-01-01

    Migratory patterns of bats are not well understood and traditional methods to study this, like capture-mark-recapture, may not provide enough detail unless there are many records. Stable isotope profiles of many animal species have been used to make inferences about migration. Each year Myotis lucifugus and M. septentrionalis migrate from summering roosts to swarming caves and mines in the fall, but the pattern of movement between them is not well understood. In this study, fur δ13C and δ15N values of 305 M. lucifugus and 200 M. septentrionalis were analyzed to make inferences about migration patterns between summering areas and swarming sites in Nova Scotia, Canada. We expected that there would be greater variability in δ13C and δ15N among individuals at swarming sites because it was believed that these sites are used by individuals originating from many summering areas. There was extensive overlap in the standard ellipse area, corrected for small sample sizes (SEAc), of bats at swarming sites and much less overlap in SEAc among groups sampled at summering areas. Meaningful inference could not be made on M. septentrionalis because their low variation in SEAc may have been the result of sampling only 3 summering areas. However, for M. lucifugus, swarming sites had larger SEAc than summering areas and predictive discriminant analysis assigned swarming bats to multiple summering areas, supporting the contention that swarming bats are mixed aggregations of bats from several summering areas. Together, these data support the contention that swarming sites have catchment areas for bats from multiple summering areas and it is likely that the catchment areas for swarming sites overlap. These data suggest that δ13C and δ15N profiling of bat fur offer some potential to make inferences about regional migration in bats.

  3. Analysis of anthropogenic impacts on the hydrological state of a Pleistocene catchment area using remote sensing techniques

    Science.gov (United States)

    Leuschner, Annette; Merz, Christoph; Steidl, Jörg; van Gasselt, Stephan

    2016-04-01

    The water budget of a catchment area can be depicted by the complex interaction between topography and discharge as well as anthropogenic and climatic impacts. Over the last decades, the Pleistocene lowlands of North-Eastern Germany have experienced extensive anthropogenic modifications. The hydrological system has been significantly altered by the installation of artificial drainage, such as surface ditches and subsurface tile drains. It has been shown, that artificial drainage systems provide pathways for diffuse nutrients and pollutants leaching into surface and also subsurface water bodies, which is especially pronounced in lowland areas. The detection of these transport paths is important for obtaining an understanding of the regional water and substance balance and the development of strategies to improve hydrological conditions. Unfortunately, detailed data about locations of historic artificial drainage are rare or not available at all. The aim of this study was to identify the extensive anthropogenic modifications, like artificial drainage networks and land use changes, over the last decades with the aid of photogrammetric data and multispectral imagery. The detection of anthropogenic modifications is based on the method of Tetzlaff, et al. (2009), who developed an approach by interpreting aerial photographs for drained areas. We used color-infrared (CIR) aerial photographs, in order to apply different spectral techniques for obtaining information about water content and vitality status of plant cover. Although this method is sensitive to daily variations of soil moisture and plant growth as response to climate conditions, and the type of drainage pipe installation technique, we were able to identify different locations of artificial drainage. Complementary to this approach we utilized spectral classification methods for land cover in order to extract different land cover categories, and evaporation rates, depending on the land cover and surface

  4. Measuring Spatial Accessibility of Health Care Providers – Introduction of a Variable Distance Decay Function within the Floating Catchment Area (FCA) Method

    Science.gov (United States)

    Groneberg, David A.

    2016-01-01

    We integrated recent improvements within the floating catchment area (FCA) method family into an integrated ‘iFCA`method. Within this method we focused on the distance decay function and its parameter. So far only distance decay functions with constant parameters have been applied. Therefore, we developed a variable distance decay function to be used within the FCA method. We were able to replace the impedance coefficient β by readily available distribution parameter (i.e. median and standard deviation (SD)) within a logistic based distance decay function. Hence, the function is shaped individually for every single population location by the median and SD of all population-to-provider distances within a global catchment size. Theoretical application of the variable distance decay function showed conceptually sound results. Furthermore, the existence of effective variable catchment sizes defined by the asymptotic approach to zero of the distance decay function was revealed, satisfying the need for variable catchment sizes. The application of the iFCA method within an urban case study in Berlin (Germany) confirmed the theoretical fit of the suggested method. In summary, we introduced for the first time, a variable distance decay function within an integrated FCA method. This function accounts for individual travel behaviors determined by the distribution of providers. Additionally, the function inherits effective variable catchment sizes and therefore obviates the need for determining variable catchment sizes separately. PMID:27391649

  5. Measuring Spatial Accessibility of Health Care Providers - Introduction of a Variable Distance Decay Function within the Floating Catchment Area (FCA) Method.

    Science.gov (United States)

    Bauer, Jan; Groneberg, David A

    2016-01-01

    We integrated recent improvements within the floating catchment area (FCA) method family into an integrated 'iFCA`method. Within this method we focused on the distance decay function and its parameter. So far only distance decay functions with constant parameters have been applied. Therefore, we developed a variable distance decay function to be used within the FCA method. We were able to replace the impedance coefficient β by readily available distribution parameter (i.e. median and standard deviation (SD)) within a logistic based distance decay function. Hence, the function is shaped individually for every single population location by the median and SD of all population-to-provider distances within a global catchment size. Theoretical application of the variable distance decay function showed conceptually sound results. Furthermore, the existence of effective variable catchment sizes defined by the asymptotic approach to zero of the distance decay function was revealed, satisfying the need for variable catchment sizes. The application of the iFCA method within an urban case study in Berlin (Germany) confirmed the theoretical fit of the suggested method. In summary, we introduced for the first time, a variable distance decay function within an integrated FCA method. This function accounts for individual travel behaviors determined by the distribution of providers. Additionally, the function inherits effective variable catchment sizes and therefore obviates the need for determining variable catchment sizes separately.

  6. [Specific Features of Radioactive Pollution of Soils of Catchment Areas of Lake Shablish (Distant Zone of the East Ural Radioactive Trace)].

    Science.gov (United States)

    Deryagin, V V; Levina, S G; Sutyagin, A A; Parfilova, N S

    2015-01-01

    Specific features of 90Sr and 137Cs distribution and accumulation in soil cuts of superaqueous and eluvial positions of catchment areas of Lake Shablish located in a distant zone of the East Ural radioactive trace are considered. Some physical and chemical characteristics of the soils were defined. It is established that the signs typical for the lake ecosystems of distant East-Ural radioactive trace zone which underwent impact of technogenic influence are common for soils of catchment areas of Lake Shablish. The distinctions in some characteristic features of the specific activity of long-living radionuclides for the soils of superaqueous and eluvial positions of catchment areas connected with the character of the water regime of soils are shown.

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

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    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

  8. Defining optimal DEM resolutions and point densities for modelling hydrologically sensitive areas in agricultural catchments dominated by microtopography

    Science.gov (United States)

    Thomas, I. A.; Jordan, P.; Shine, O.; Fenton, O.; Mellander, P.-E.; Dunlop, P.; Murphy, P. N. C.

    2017-02-01

    Defining critical source areas (CSAs) of diffuse pollution in agricultural catchments depends upon the accurate delineation of hydrologically sensitive areas (HSAs) at highest risk of generating surface runoff pathways. In topographically complex landscapes, this delineation is constrained by digital elevation model (DEM) resolution and the influence of microtopographic features. To address this, optimal DEM resolutions and point densities for spatially modelling HSAs were investigated, for onward use in delineating CSAs. The surface runoff framework was modelled using the Topographic Wetness Index (TWI) and maps were derived from 0.25 m LiDAR DEMs (40 bare-earth points m-2), resampled 1 m and 2 m LiDAR DEMs, and a radar generated 5 m DEM. Furthermore, the resampled 1 m and 2 m LiDAR DEMs were regenerated with reduced bare-earth point densities (5, 2, 1, 0.5, 0.25 and 0.125 points m-2) to analyse effects on elevation accuracy and important microtopographic features. Results were compared to surface runoff field observations in two 10 km2 agricultural catchments for evaluation. Analysis showed that the accuracy of modelled HSAs using different thresholds (5%, 10% and 15% of the catchment area with the highest TWI values) was much higher using LiDAR data compared to the 5 m DEM (70-100% and 10-84%, respectively). This was attributed to the DEM capturing microtopographic features such as hedgerow banks, roads, tramlines and open agricultural drains, which acted as topographic barriers or channels that diverted runoff away from the hillslope scale flow direction. Furthermore, the identification of 'breakthrough' and 'delivery' points along runoff pathways where runoff and mobilised pollutants could be potentially transported between fields or delivered to the drainage channel network was much higher using LiDAR data compared to the 5 m DEM (75-100% and 0-100%, respectively). Optimal DEM resolutions of 1-2 m were identified for modelling HSAs, which balanced the need

  9. Ethnicity, Education, and the Temporal Stability of Personality Traits In the East Baltimore Epidemiologic Catchment Area Study.

    Science.gov (United States)

    Löckenhoff, Corinna E; Terracciano, Antonio; Bienvenu, O Joseph; Patriciu, Nicholas S; Nestadt, Gerald; McCrae, Robert R; Eaton, William W; Costa, Paul T

    2008-01-01

    We examined the influence of age, gender, Black vs. White ethnicity, and education on five indices of personality stability and change across an average interval of 8 years in the East Baltimore Epidemiologic Catchment Area study. In the full sample (n = 505, aged 30-88), examination of structural, rank-order, ipsative, and mean level stability, as well as indices of reliable change suggested that NEO-PI-R personality traits showed moderate to high levels of stability over time. There were few age and gender effects on temporal stability but rank-order, ipsative, and mean level stability were lower among Blacks and individuals with lower education. Future research should explore additional demographic predictors of temporal plasticity in a diverse range of samples, and employ observer ratings to assess personality.

  10. Determinants of the utilization of diversified types of professionals for mental health reasons in a Montreal (Canadian) catchment area.

    Science.gov (United States)

    Fleury, Marie-Josée; Grenier, Guy; Bamvita, Jean-Marie; Perreault, Michel; Caron, Jean

    2012-04-28

    The study was designed to identify factors associated with the diversity of professionals consulted by 212 individuals affected by at least one mental disorder in the past 12 months in a Montreal catchment area. For inclusion in the study, participants had to be aged 15 to 65 and reside in the study zone. A comprehensive set of variables were analyzed in accordance with the Andersen's behavioural model of health service use. General practitioners, psychiatrists, and psychologists were the main professionals consulted in this study. Having post-secondary education, more than a single mental disorder, excellent relationships with neighbours, and (marginally) being a lifelong victim of violence were associated with higher numbers of professionals consulted. As this study highlights the large number of diversified professionals consulted for reason of mental disorders, shared care initiatives may prove beneficial. Greater effort could also be made in increasing services toward those deemed more vulnerable.

  11. Defining health catchment areas in Jeddah city, Saudi Arabia: an example demonstrating the utility of geographical information systems

    Directory of Open Access Journals (Sweden)

    Abdulkader A. Murad

    2008-05-01

    Full Text Available A tool, based on a geographical information system (GIS approach, has been developed for the location and organization of public health care centers in Jeddah city, Saudi Arabia. The potential of GIS for visualizing and modeling available information on health-care has been utilized to produce a “best-fit application”. This paper identifies and deals with the manner in which GIS can successfully be used for evaluating the demand and supply of health care facilities as well as be applied for defining health catchment areas. The study uses the essential achievements gained to analyze the advantages of GIS for health care planning and the location of health care centers. Some specific GIS tools, as well as single and multiple spatial search functions, are presented.

  12. Detection of Catchment-Scale Gully-Affected Areas Using Unmanned Aerial Vehicle (UAV on the Chinese Loess Plateau

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    Kai Liu

    2016-12-01

    Full Text Available The Chinese Loess Plateau suffers from serious gully erosion induced by natural and human causes. Gully-affected areas detection is the basic work in this region for gully erosion assessment and monitoring. For the first time, an unmanned aerial vehicle (UAV was applied to extract gully features in this region. Two typical catchments in Changwu and Ansai were selected to represent loess tableland and loess hilly regions, respectively. A high-powered quadrocopter (md4-1000 equipped with a non-metric camera was used for image acquisition. InPho and MapMatrix were applied for semi-automatic workflow including aerial triangulation and model generation. Based on the stereo-imaging and the ground control points, the highly detailed digital elevation models (DEMs and ortho-mosaics were generated. Subsequently, an object-based approach combined with the random forest classifier was designed to detect gully-affected areas. Two experiments were conducted to investigate the influences of segmentation strategy and feature selection. Results showed that vertical and horizontal root-mean-square errors were below 0.5 and 0.2 m, respectively, which were ideal for the Loess Plateau region. The overall extraction accuracy in Changwu and Ansai achieved was 84.62% and 86.46%, respectively, which indicated the potential of the proposed workflow for extracting gully features. This study demonstrated that UAV can bridge the gap between field measurement and satellite-based remote sensing, obtaining a balance in resolution and efficiency for catchment-scale gully erosion research.

  13. Managing the drinking water catchment areas: the French agricultural cooperatives feed back.

    Science.gov (United States)

    Charrière, Séverine; Aumond, Claire

    2016-06-01

    The quality of raw water is problematic in France, largely polluted by nitrates and pesticides (Mueller and Helsel, Nutrients in the nation's waters-too much of a good thing? Geological Survey (U.S.), 1996; European Environment Agency, European waters-assessment of status and pressures, 2012).This type of pollution, even though not always due to agriculture (example of the catchment of Ambleville, county 95, France where the nitrate pollution is mainly due to sewers (2012)), has been largely related to the agricultural practices (Sci Total Environ 407:6034-6043, 2009).Taking note of this observation, and instead of letting it paralyze their actions, the agricultural cooperatives decided with Agrosolutions to act directly on the field with their subscribers to change the agricultural practices impacting the water and the environment.This article shows how the French agricultural cooperatives transformed the awareness of the raw water quality problem into an opportunity for the development and implementation of more precise and responsible practices, to protect their environment. They measure in order to pilot, co-construct and build the best action plans possible according to the three pillars of environment, economy and agronomy.

  14. CONDITIONS OF FISH FARMING IN NATURA 2000 AREAS, BASED ON THE EXAMPLE OF THE CATCHMENT OF BARYCZ

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    Katarzyna Tokarczyk-Dorociak

    2016-07-01

    Full Text Available One of the factors that contributed to the construction of approx.77 km2 offish ponds in the catchment of Barycz starting from the 13th century, which in turn transformed the woods into a mosaic of waters, forests and arable land, were the advantageous physiographic conditions. Fish farming operations conducted in this area led to the creation of a cultural landscape characterised by unique natural values, similar to the natural landscape.Approx.240 species of birds are observed here, of which 170 are nesting species. Due to its natural values, this area has been subject to natural reserve protection as part of the Landscape Park "Dolina Baryczy" (the Barycz Valley. It was entered in the "Living Lakes" list and it is protected under the Ramsar Convention as well as under the European nature protection network Natura 2000.The established forms of nature protection mean the introduction of a certain binding regime, pursuant to which the economic activity conducted in protected areas must take into account the prohibitions and orders introduced by documents that establish the said forms of protection. Additionally, there is a legal requirement to create a protection plan or conservation plan that constitutes a basis for the realisation of conservation-related objectives. A commercial company Stawy Milickie S.A. (public limited company operates in the area of this largest fish pond complex in Poland. The scope of its operations includes more than just the breeding and sale of freshwater fish (6500 ha of ponds but also environmental protection, environmental education and the development of tourism as well as stimulating the development and professional activation of local communities basing on the natural resources that exist in the catchment of Barycz. This study presents the conditions related to fish farming operations conducted in this area. Conducting an extensive management (i.e. often uneconomical from the economic point of view is a

  15. 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.

  16. Modelling the spatial distribution of snow water equivalent at the catchment scale taking into account changes in snow covered area

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    T. Skaugen

    2011-12-01

    Full Text Available A successful modelling of the snow reservoir is necessary for water resources assessments and the mitigation of spring flood hazards. A good estimate of the spatial probability density function (PDF of snow water equivalent (SWE is important for obtaining estimates of the snow reservoir, but also for modelling the changes in snow covered area (SCA, which is crucial for the runoff dynamics in spring. In a previous paper the PDF of SWE was modelled as a sum of temporally correlated gamma distributed variables. This methodology was constrained to estimate the PDF of SWE for snow covered areas only. In order to model the PDF of SWE for a catchment, we need to take into account the change in snow coverage and provide the spatial moments of SWE for both snow covered areas and for the catchment as a whole. The spatial PDF of accumulated SWE is, also in this study, modelled as a sum of correlated gamma distributed variables. After accumulation and melting events the changes in the spatial moments are weighted by changes in SCA. The spatial variance of accumulated SWE is, after both accumulation- and melting events, evaluated by use of the covariance matrix. For accumulation events there are only positive elements in the covariance matrix, whereas for melting events, there are both positive and negative elements. The negative elements dictate that the correlation between melt and SWE is negative. The negative contributions become dominant only after some time into the melting season so at the onset of the melting season, the spatial variance thus continues to increase, for later to decrease. This behaviour is consistent with observations and called the "hysteretic" effect by some authors. The parameters for the snow distribution model can be estimated from observed historical precipitation data which reduces by one the number of parameters to be calibrated in a hydrological model. Results from the model are in good agreement with observed spatial moments

  17. Modelling the spatial distribution of snow water equivalent at the catchment scale taking into account changes in snow covered area

    Science.gov (United States)

    Skaugen, T.; Randen, F.

    2011-12-01

    A successful modelling of the snow reservoir is necessary for water resources assessments and the mitigation of spring flood hazards. A good estimate of the spatial probability density function (PDF) of snow water equivalent (SWE) is important for obtaining estimates of the snow reservoir, but also for modelling the changes in snow covered area (SCA), which is crucial for the runoff dynamics in spring. In a previous paper the PDF of SWE was modelled as a sum of temporally correlated gamma distributed variables. This methodology was constrained to estimate the PDF of SWE for snow covered areas only. In order to model the PDF of SWE for a catchment, we need to take into account the change in snow coverage and provide the spatial moments of SWE for both snow covered areas and for the catchment as a whole. The spatial PDF of accumulated SWE is, also in this study, modelled as a sum of correlated gamma distributed variables. After accumulation and melting events the changes in the spatial moments are weighted by changes in SCA. The spatial variance of accumulated SWE is, after both accumulation- and melting events, evaluated by use of the covariance matrix. For accumulation events there are only positive elements in the covariance matrix, whereas for melting events, there are both positive and negative elements. The negative elements dictate that the correlation between melt and SWE is negative. The negative contributions become dominant only after some time into the melting season so at the onset of the melting season, the spatial variance thus continues to increase, for later to decrease. This behaviour is consistent with observations and called the "hysteretic" effect by some authors. The parameters for the snow distribution model can be estimated from observed historical precipitation data which reduces by one the number of parameters to be calibrated in a hydrological model. Results from the model are in good agreement with observed spatial moments of SWE and SCA

  18. Valuation of environmental problems in landfill deposition and composting - test of methodology; Verdsetting av miljoekonsekvenser av avfallsdeponering og kompostering - metodeutproeving

    Energy Technology Data Exchange (ETDEWEB)

    Leknes, Einar; Movik, Espen; Wiik, Ragnhild; Meissnes, Rudolf

    1995-08-01

    This study is aimed at the tests and design of methods for valuation of environmental problems associated with the landfill deposition of household waste. An extensive review of literature has been conducted with respect to the environmental impacts and valuation methods. Environmental impact assessment and valuation with respect to emission of greenhouse gases (GHG's), leachate and disamenity, have been performed for 4 Norwegian landfills. These differ in their approach towards waste treatment in terms of GHG-collection, briquette production and composting and also in their location in terms of proximity to residential areas and the quality of natural recipients. The study shows that the collection of methane and production of briquettes causes major reductions in the generation of GHG's, whereas composting brings significant reductions for all types of environmental impacts. (author)

  19. Subjective quality of life and its determinants in a catchment area based population of elderly schizophrenia patients.

    Science.gov (United States)

    Meesters, Paul D; Comijs, Hannie C; de Haan, Lieuwe; Smit, Johannes H; Eikelenboom, Piet; Beekman, Aartjan T F; Stek, Max L

    2013-07-01

    Subjective quality of life (SQOL) is an established outcome measure in schizophrenia. In spite of the substantial proportion of elderly in the total schizophrenia population, evaluation of their SQOL and its determinants has been scarce and findings from epidemiological samples are lacking. We assessed SQOL in elderly Dutch patients with schizophrenia or schizoaffective disorder (n=107; mean age 68 years), treated within a psychiatric catchment area. Demographic, clinical and social variables were evaluated for their impact on SQOL. The mean SQOL score was 4.83, moderately surpassing the midpoint of the SQOL scale. Nearly half of all patients (47.7%) reported an overall favorable SQOL. Of the total variance in SQOL, clinical variables explained 50%, and social variables explained 16%, while demographic factors did not contribute. In multivariable analysis, less self-reported depressive symptoms, worse global neurocognition, and higher observer-based level of social functioning significantly predicted a higher SQOL, explaining 53% of the total variance. The relatively high level of SQOL in this epidemiological sample of elderly patients is in line with what has been reported for both older and younger schizophrenia populations. Depressive symptoms are a robust predictor of SQOL in late life schizophrenia, clearly outweighing psychotic symptoms. This finding has major clinical relevance, as depression is amenable to therapeutic intervention. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Projected Change in Climate Under A2 Scenario in Dal Lake Catchment Area of Srinagar City in Jammu and Kashmir

    Directory of Open Access Journals (Sweden)

    Saqib Parvaze1,

    2016-08-01

    Full Text Available The present study was done to study the effect of climate change on weather parameters like highest possible temperature, lowest possible temperature, average temperature and precipitation. Multiple linear Regression (MLR, Artificial Neural Network (ANN and Statistical Downscaling Model (SDSM models were tested in the Dal lake catchment area of Jammu and Kashmir State. Twenty seven year weather data (1985-2012 obtained from SKUAST-Kashmir weather station was used for the study. The modeling results showed a first-rate agreement between the observed data and predicted values for temperature series with high coefficient of determination R2 values varying from (0.87-0.97 for different models. In case of precipitation R2 values varied from (0.112-219 for different models. The low values of coefficient of determination in precipitation time series are due to lot of uncertainty in occurrence of precipitation which could not be defined by the selected models. The SDSM showed the best results of the three models tested for prediction of weather parameters. Thus SDSM was used for climate scenario generation. By comparing daily precipitation and temperature series for 1985-2012 with 2015-2030, an overall increasing pattern of 0.46%, 1.96%, 0.95% and 2.66% was observed for monthly, highest possible temperature, lowest possible temperature, average temperature and precipitation.

  1. Effects of a drought period on physico-chemical surface water quality in a regional catchment area.

    Science.gov (United States)

    Wilbers, Gert-Jan; Zwolsman, Gertjan; Klaver, Gerard; Hendriks, A Jan

    2009-06-01

    Hydrological drought periods are expected to become more severe in North-Western Europe as a result of climate change. This may have implications for water quality, as demonstrated by declining water quality of large rivers (e.g. Rhine, Meuse) during droughts. However, similar investigations in regional catchment areas are lacking to date. In the present study, we investigated the effects of a drought period on the water quality of the Dommel River, a tributary of the Meuse river in the Netherlands. Water quality during the drought of 2003 was compared to that in reference years (2004-2006) for 18 physical/chemical parameters using ANOVA analysis. It was demonstrated that the drought period of 2003 did not significantly affect water quality, although the origin of river flow during the drought shifted from mainly overland flow to deep groundwater flow and (treated) communal effluents. Significant differences in water quality were noted for some monitoring stations during the study period, which could be related to operational water management such as cleaning of sediment traps in the river and improvements in communal effluent treatment. The results of this study are interesting to water managers in Western Europe as they contribute to understanding the potential impact of climate change on water quality/quantity patterns in regional water systems.

  2. Estimating the prevalence of mental disorders in U.S. adults from the Epidemiologic Catchment Area Survey.

    Science.gov (United States)

    Bourdon, K H; Rae, D S; Locke, B Z; Narrow, W E; Regier, D A

    1992-01-01

    The National Institute of Mental Health Epidemiologic Catchment Area Survey is a comprehensive, community-based survey of mental disorders and use of services by adults, ages 18 and older. Diagnoses are based on the criteria in the "Diagnostic and Statistical Manual of Mental Disorders," third edition, and were obtained in five communities in the United States through lay-interviewer administration of the National Institute of Mental Health Diagnostic Interview Schedule. Results from the survey provide the public health field with data on the prevalence and incidence of specific mental disorders in the community, unbiased by the treatment status of the sample. The population with disorders is estimated, and the survey findings that respond to some of the most common requests for information about the epidemiology of mental disorders in the United States are highlighted briefly. Based on the survey, it is estimated that one of every five persons in the United States suffers from a mental disorder in any 6-month period, and that one of every three persons suffers a disorder in his or her lifetime. Fewer than 20 percent of those with a recent mental disorder seek help for their problem, according to the survey. High rates of comorbid substance abuse and mental disorders were found, particularly among those who had sought treatment for their disorders.

  3. Environmental modelling of Omerli catchment area in Istanbul, Turkey using remote sensing and GIS techniques.

    Science.gov (United States)

    Coskun, H Gonca; Alparslan, Erhan

    2009-06-01

    Omerli Reservoir is one of the major drinking water reservoirs of Greater Metropolis Istanbul, providing 40% of the overall water demand. Istanbul where is one of the greatest metropolitan areas of the world with a population over 10 million and a rate of population increase about twice that of Turkey. As a result of population growth and industrial development, Omerli watershed is highly affected by the wastewater discharges from the residential areas and industrial plants. The main objective of this study is to investigate the temporal assessment of the land-use/cover of the Omerli Watershed and the water quality changes in the Reservoir. It is not possible to adequately control urbanization and other pollution sources affecting the water quality. Responses of these detrimental effects are due to rapidly increasing population, unplanned and illegal housing, and irrelevant industries at the protection zones of the watershed, together with insufficient infrastructure. The study is focused on the assessment of urbanization in relation to land use and water quality using Remote Sensing (RS) and Geographic Information Systems (GIS) techniques for all the four protection zones of the Reservoir and a time variant analyzing model is obtained. IRS-1C LISS and IRS-1C PAN, LANDSAT-5 TM satellite data of 1997, 1998, 2000, 2001 and 2006 are analyzed by confirmation through the ground truth data. RS data have been transferred into UTM coordinate system and image enhancement and classification techniques were used. Raster data were converted to vector data that belongs to study area to analyze in GIS for the purpose of planning and decision-making on protected watersheds.

  4. Roads as sources of heavy metals in urban areas. The Covões Catchment experiment, Coimbra, Portugal

    Science.gov (United States)

    Ferreira, António J. D.; Soares, Daniel; Ferreira, Carla S. S.; Walsh, Rory P. D.

    2015-04-01

    Cities are the home to 50% of the human specie [UN 2011 Ramalho & Hobbs 2012], whose wellbeing, way of life and exposure to hazard situations are directly related to the built environment. Cities are often seen as ecological systems just a short step away from collapse [Newman 2006]. Being a human construction, cities disrupt the natural cycles and the patterns of temporal and spatial distribution of environmental and ecological processes. Urbanization produces ruptures in biota, water, energy and nutrients connectivity that can lead to an enhanced exposure to disruptive events that hamper the wellbeing and the resilience of urban communities in a global change context. A major issue in what concerns the threats to human and ecosystem health in urban areas is the presence of heavy metals, and the related processes that govern their source, transport and fade r uptake by the vegetation. In this work, we present an analysis of heavy metal sources and transport processes at various types of roads within the Ribeira dos Covões peri-urban experimental catchment in central Portugal. The surveyed heavy metals (Cadmium, Lead, Coper, and Zinc) show significant differences as a result of the type of rainfall event, the length of the antecedent dry spell, the traffic volume and the heavy metals sources. For some locations, namely for the roads with heavy traffic volume, the heavy metal concentrations exceed the limits established by law, which has severe implications to the downstream ecosystems and to the possible use of the water from roads to close the resources loop in urban areas, namely in what concerns their use to water the urban green infrastructure or to irrigate the urban agriculture fields.

  5. Modelling of Radiological Health Risks from Gold Mine Tailings in Wonderfonteinspruit Catchment Area, South Africa

    Directory of Open Access Journals (Sweden)

    Manny Mathuthu

    2016-06-01

    Full Text Available Mining is one of the major causes of elevation of naturally-occurring radionuclide material (NORM concentrations on the Earth’s surface. The aim of this study was to evaluate the human risk associated with exposure to NORMs in soils from mine tailings around a gold mine. A broad-energy germanium detector was used to measure activity concentrations of these NORMs in 66 soil samples (56 from five mine tailings and 10 from the control area. The RESidual RADioactivity (RESRAD OFFSITE modeling program (version 3.1 was then used to estimate the radiation doses and the cancer morbidity risk of uranium-238 (238U, thorium-232 (232Th, and potassium-40 (40K for a hypothetical resident scenario. According to RESRAD prediction, the maximum total effective dose equivalent (TEDE during 100 years was found to be 0.0315 mSv/year at year 30, while the maximum total excess cancer morbidity risk for all the pathways was 3.04 × 10−5 at year 15. The US Environmental Protection Agency considers acceptable for regulatory purposes a cancer risk in the range of 10−6 to 10−4. Therefore, results obtained from RESRAD OFFSITE code has shown that the health risk from gold mine tailings is within acceptable levels according to international standards.

  6. Modelling of Radiological Health Risks from Gold Mine Tailings in Wonderfonteinspruit Catchment Area, South Africa

    Science.gov (United States)

    Mathuthu, Manny; Kamunda, Caspah; Madhuku, Morgan

    2016-01-01

    Mining is one of the major causes of elevation of naturally-occurring radionuclide material (NORM) concentrations on the Earth’s surface. The aim of this study was to evaluate the human risk associated with exposure to NORMs in soils from mine tailings around a gold mine. A broad-energy germanium detector was used to measure activity concentrations of these NORMs in 66 soil samples (56 from five mine tailings and 10 from the control area). The RESidual RADioactivity (RESRAD) OFFSITE modeling program (version 3.1) was then used to estimate the radiation doses and the cancer morbidity risk of uranium-238 (238U), thorium-232 (232Th), and potassium-40 (40K) for a hypothetical resident scenario. According to RESRAD prediction, the maximum total effective dose equivalent (TEDE) during 100 years was found to be 0.0315 mSv/year at year 30, while the maximum total excess cancer morbidity risk for all the pathways was 3.04 × 10−5 at year 15. The US Environmental Protection Agency considers acceptable for regulatory purposes a cancer risk in the range of 10−6 to 10−4. Therefore, results obtained from RESRAD OFFSITE code has shown that the health risk from gold mine tailings is within acceptable levels according to international standards. PMID:27338424

  7. Mapping soil organic carbon stock in the area of Neamtu Catchment, Northeastern Romania

    Science.gov (United States)

    Breaban, Ana-Ioana; Bobric, Elena-Diana; Breaban, Iuliana-Gabriela; Rusu, Eugen

    2017-04-01

    The quantification of soil organic carbon stocks and its spatial extent is directly influenced by the land cover. The aim of the study is to quantify both the spatial distribution of soil organic carbon and stocks under different soil types and land uses in an area of 41.808,04 ha in northeastern part of Romania. It has been studied the evolution of carbon stocks over time, taking into account the change of land use between 1990-2012 under 5 classes: forests, pastures, arable land, orchard and built spaces. Common soils are Cambisols, Fluvisols, Phaezems, and Luvisols, forest being the predominant land use. The most important loss of soil organic carbon occurs as a result of changes in the supply of biomass supplying litter and therefore the process of bioaccumulation. The samples were collected from 100 representative soil profiles and analyzed with Analytik Jena multi N/C 2100 with HT 1300 solid module. Based on the soil organic carbon, C/N ratio and texture the values of those parameters varied from high values in Ao and Bv horizons to lower values in C horizon. In order to model soil organic carbon concentration were used different interpolation techniques (regression and ordinary -kriging, IDW) at different sampling densities for each depth to 100 cm, using a Gaussian approach to estimate the uncertainty. It is noticeable that soil organic carbon had a positive correlation with different types of land uses and a negative correlation with the elevation, being a decreasing trend of the carbon stocks sequestered in biomass, litter and soil. In the upper part of the profiles, the soil organic carbon stock considerably varied for forest land between 6.5-7.23 kg C/sqm) and agricultural land (3.67-4.65 kg C/sqm). The kriging regression evidenced a good variability of the calculated root mean square errors of the predicted soil organic carbon stocks.

  8. Popliteal artery injuries in an urban trauma center with a rural catchment area: do delays in definitive treatment affect amputation?

    Science.gov (United States)

    Simmons, Jon D; Gunter, Joseph W; Schmieg, Robert E; Manley, Justin D; Rushton, Fred W; Porter, John M; Mitchell, Marc E

    2011-11-01

    Extended length of time from injury to definitive vascular repair is considered to be a predictor of amputation in patients with popliteal artery injuries. In an urban trauma center with a rural catchment area, logistical issues frequently result in treatment delays, which may affect limb salvage after vascular trauma. We examined how known risk factors for amputation after popliteal trauma are affected in a more rural environment, where patients often experience delays in definitive surgical treatment. All adult patients admitted to the Level I trauma center, the University of Mississippi Medical Center, with a popliteal artery injury between January 2000 and December of 2007 were identified. Demographic information management and outcome data were collected. Body mass index, mangled extremity severity score (MESS), Guistilo open fracture score, injury severity score, and time from injury to vascular repair were examined. Fifty-one patients with popliteal artery injuries (53% blunt and 47% penetrating) were identified, all undergoing operative repair. There were nine amputations (17.6%) and one death. Patients requiring amputation had a higher MESS, 7.8 versus 5.3 (P score, Guistilo open fracture score, or time from injury to repair were not different between the two groups. Patients with a blunt mechanism of injury had a slightly higher amputation rate compared with those with penetrating trauma, 25.9 per cent versus 8.3 per cent (P = non significant). MESS, though not perfect, is the best predictor of amputation in patients with popliteal artery injuries. Morbid obesity is not a significant predictor for amputation in patients with popliteal artery injuries. Time from injury to repair of greater than 6 hours was not predictive of amputation. This study further demonstrates that a single scoring system should be used with caution when determining the need for lower extremity amputation.

  9. First Results of using the Process-based Model PROMAB-GIS for Runoff a Bedload Transport Estimation in the Lainbach Torrent Catchment Area (Benediktbeuern, Germany)

    Science.gov (United States)

    Rinderer, M.; Jenewein, S.; Ploner, A.; Sönser, T.

    2003-04-01

    As growing damage potential makes society more and more vulnerable to natural hazards, the pressure on the official authorities responsible for the guarantee of public safety is increasing rapidly. Modern computer technology, e.g. Geographical Information Systems (GIS), can provide remarkable help in assessing the risks resulting from natural hazards. The modelling in PROMAB-GIS, which is an user friendly software based on ESRI ArcView for assessing runoff and bedload transport in torrent catchments, is strongly based on interdisciplinary process-orientated field investigations. This paper presents results of the application of PROMAB-GIS to estimate the runoff and bedload transport potential of the Lainbach catchment area which has repeatedly been affected by heavy rain storms triggering remarkable events. The operational steps needed to gain process orientated, reproducible results for assessing design events in watersheds are highlighted. A key issue in this context is the need for detailed field-investigation of the geo-, bio-, hydro-inventory of a catchment area. The second part of the paper presents the model results for design events. The data of the event which caused severe damage in June 1990 provides a perfect basis for the evaluation of the model. The results show the potential of PROMAB-GIS for assessing runoff and bedload transport in alpine torrent systems.

  10. Spatial patterns of incident malaria cases and their household contacts in a single clinic catchment area of Chongwe District, Zambia.

    Science.gov (United States)

    Pinchoff, Jessie; Henostroza, German; Carter, Bryan S; Roberts, Sarah T; Hatwiinda, Sisa; Hamainza, Busiku; Hawela, Moonga; Curriero, Frank C

    2015-08-07

    Reactive case detection (RACD) for malaria is a strategy that may be used to complement passive surveillance, as passive surveillance fails to identify infections that are asymptomatic or do not seek care. The spatial and seasonal patterns of incident (index) cases reported at a single clinic in Chongwe District were explored. A RACD strategy was implemented from June 2012 to June 2013 in a single catchment area in Chongwe District. Incident (index) cases recorded at the clinic were followed up at their household, and all household contacts were tested for malaria using rapid diagnostic tests (RDTs). GPS coordinates were taken at each index household. Spatial analyses were conducted to assess characteristics related to clustering, cluster detection and spatial variation in risk of index houses. Effects of season (rainy versus dry), distance to the clinic and distance to the main road were considered as modifying factors. Lastly, logistic regression was used to identify factors associated with the proportion of household contacts testing RDT positive. A total of 426 index households were enrolled, with 1,621 household contacts (45% RDT positive). Two space-time clusters were identified in the rainy season, with ten times and six times higher risk than expected. Significantly increased spatial clustering of index households was found in the rainy season as compared to the dry season (based on K-function methodology). However, no seasonal difference in mapped spatial intensity of index households was identified. Logistic regression analysis identified two main factors associated with a higher proportion of RDT positive household contacts. There was a 41% increased odds of RDT positive household contacts in households where the index case was under 5 years of age [OR = 1.41, 95% confidence intervals (1.15, 1.73)]. For every 500-m increase in distance from the road, there was a 5% increased odds of RDT positive household contacts [OR = 1.05 (1.02, 1.07)], controlling

  11. Assessing calves as carriers of Cryptosporidium and Giardia with zoonotic potential on dairy and beef farms within a water catchment area by mutation scanning.

    Science.gov (United States)

    Abeywardena, Harshanie; Jex, Aaron R; Firestone, Simon M; McPhee, Sandra; Driessen, Nicole; Koehler, Anson V; Haydon, Shane R; von Samson-Himmelstjerna, Georg; Stevens, Melita A; Gasser, Robin B

    2013-08-01

    In the present study, we undertook a molecular epidemiological survey of Cryptosporidium and Giardia in calves on three dairy and two beef farms within an open drinking water catchment area (Melbourne, Australia). Faecal samples (n = 474) were collected from calves at two time points (5 months apart) and tested using a PCR-based mutation scanning-targeted sequencing phylogenetic approach, employing regions within the genes of small subunit (SSU) of ribosomal RNA (designated partial SSU), 60 kDa glycoprotein (pgp60) and triose phosphate isomerase (ptpi) as genetic markers. Using partial SSU, the C. bovis, C. parvum, C. ryanae and a new genotype of Cryptosporidium were characterised from totals of 74 (15.6%), 35 (7.3%), 37 (7.8%) and 9 (1.9%) samples, respectively. Using pgp60, C. parvum genotype IIa subgenotype A18G3R1 was detected in 29 samples. Using ptpi, G. duodenalis assemblages A and E were detected in totals of 10 (2.1%) and 130 (27.4%) samples, respectively. The present study showed that a considerable proportion of dairy and beef calves in this open water catchment region excreted Cryptosporidium (i.e. subgenotype IIaA18G3R1) and Giardia (e.g. assemblage A) that are consistent with those infecting humans, inferring that they are of zoonotic importance. Future work should focus on exploring, in a temporal and spatial way, whether these parasites occur in the environment and water of the catchment reservoir.

  12. IMPACT OF URBANISATION ON LANDUSE IN A PERI-URBAN, CHENNAI – A CASE STUDY OF CATCHMENT AND COMMAND AREA OF CHEMBARAMBAKKAM TANK

    Directory of Open Access Journals (Sweden)

    S. DHATCHAYANI

    2013-04-01

    Full Text Available Water plays a vital role in the developmental activities of any country. Present mismanagement of water resources causes future deterioration, both in quantity and quality. Increase in population causes changes in the landuse / landcover in the peri-urban areas. The Chembarambakkam tank taken for study has recently been developed as a major source of water supply to the Chennai city. It has maximum storage capacity of 103 MFt. The major treatment plant of 530 MLD has been commissioned on July 2007. It is necessary to safeguard the existing water resources and analyse the present status of the water body. The catchment area contributes to the inflow and the quantity of water is analysed by estimating the runoff from the catchment area using Soil Conservation Services – Curve Number (SCS-CN model. Water released to the command area for irrigation is analysed from the secondary data. The landuse / landcover change in the command area was identified by comparing the satellite imageries of the years 1991 and 2003. Questionnaire and Participatory Rural Appraisal (PRA tools like village mapping and time – line analysis were used to get the social and economic data to analyse the reasons for changes in landuse. This project proves that urbanization and industrialization has reduced the irrigation to the worst level.

  13. Coupling of Markov chains and cellular automata spatial models to predict land cover changes (case study: upper Ci Leungsi catchment area)

    Science.gov (United States)

    Marko, K.; Zulkarnain, F.; Kusratmoko, E.

    2016-11-01

    Land cover changes particular in urban catchment area has been rapidly occur. Land cover changes occur as a result of increasing demand for built-up area. Various kinds of environmental and hydrological problems e.g. floods and urban heat island can happen if the changes are uncontrolled. This study aims to predict land cover changes using coupling of Markov chains and cellular automata. One of the most rapid land cover changes is occurs at upper Ci Leungsi catchment area that located near Bekasi City and Jakarta Metropolitan Area. Markov chains has a good ability to predict the probability of change statistically while cellular automata believed as a powerful method in reading the spatial patterns of change. Temporal land cover data was obtained by remote sensing satellite imageries. In addition, this study also used multi-criteria analysis to determine which driving factor that could stimulate the changes such as proximity, elevation, and slope. Coupling of these two methods could give better prediction model rather than just using it separately. The prediction model was validated using existing 2015 land cover data and shown a satisfactory kappa coefficient. The most significant increasing land cover is built-up area from 24% to 53%.

  14. Developing a playground as catchment area in effort to maintaining groundwater in Jaten village of Karanganyar district of Central Java, Indonesia

    Science.gov (United States)

    Legowo, Budi; Darsono; Wahyuningsih, Daru

    2016-11-01

    Changes in land use for housing indirectly disturb the hydrology balance of the area. Groundwater conservation efforts can be done by keeping the function the catchment area. One of the housing developer's obligations is providing open spaces (the playground) to play or activity of the residents. Playground in Bumi Graha Indah Housing, Jaten village, Karanganyar district, Central Java, Indonesia has a fundamental issue, that is, in the rainy season the water is difficult to seep due landfill process are not well planned. It causes the playground become in muddy conditions with tall grass, so that reduces the function as a playground and or activity the residents. In the dry season, the soil dry of landfill caused dust scattering and disrupt the activities of people around the playground. Lack of water resources lead watering process for solving the problem of dust during the dry season was considered ineffective. Structuring drainage combined with modified recharge wells can be used to catch water runoff housing. This modification of water catchment areas can make playground dry quickly after rain so the activities of people are not bothered when utilizing the open space provided. Surface runoff water absorbed in open aquifer so that the hydrological balance always be maintained. Adequacy groundwater in the area playground can be used to sprinkler dust and backup needs clean water residents by creating wells and reservoir stocks.

  15. 导向标志可见域的实验研究%Experimental study on the visibility catchment area of direction sign

    Institute of Scientific and Technical Information of China (English)

    宋冰雪; 吴宗之; 谢昱姝; 代宝乾; 刘晨

    2012-01-01

    在介绍可见域概念的基础上,将导向标志可见域转化为偏移角和观察距离的关系,开展了不同偏移角下导向标志观察距离的测量实验,分别测定了两种导向标志类型(电光源型和磷光型)在两种环境照度水平(正常照明和无照明)下,9种偏移角(0°、10°、20°、30°、40°、50°、60°、70°和80°)所对应的观察距离.实验发现随着偏移角的增加,观察距离非线性的减少,导向标志的可见域为椭圆形,该椭圆的短轴是偏移角为0°时的观察距离,该项实验的开展为导向标志可见域的确定提供了基础数据.%Based on the introduction of the visibility catchment area of direction sign, the visibility catchment area of direction sign is quantified by the relationship of the bias angle with the observational distance. The experiments for measuring the observational distance of direction sign under different bias angles are conducted, and as a result the observational distance for two types of direction sign (electrically powered components and phosphorescent components) and two kinds of luminance level (normal lighting and no lighting) as well as nine bias angles (0°, 10°, 20° 、30° 、40° 、50° 、60° 、70°、 80° ) are measured. It is found that with the increasing of bias angle, the observational distance will be reduced nonlinearly. The visibility catchment area of direction sign is an ellipse, and the size of ellipse short axis is equal to the observational distance under the 0 degree bias angle. The experiments establish the fundamental dataset for the calibration of the visibility catchment area of direction sign.

  16. Tests of Climate Change Effects on the Applicability of Flood Frequency Analysis in the Fulda Catchment Area, Germany

    Science.gov (United States)

    Fink, Gabriel Stefan Maria; Koch, Manfred

    2010-05-01

    , maximum and minimum daily temperature, and relative humidity. The calibration-validation period 1960-2000 serves as a reference period for the 21st century predictions. To test the FFA conditions for the simulated flood time series of the 21st century, the whole investigation period 1960-2100 has been split into the parts C20 (1960-2000), T1 (2001-2050), and T2 (2051-2100), each of which is then subjected to various statistical time-series tests. For example, a simple test of the stationarity of the mean cannot indicate significant changes in the mean behavior between these periods. Additionally, the χ2-test leads to the adaption of the hypothesis that there is no change in the distribution function for all three climate scenarios. The application of the Mann-Whitney trend test and the Mann-Kendall trend test prove the stationarity (α=0.05) of the flow time series. Wald-Wolfowitz tests and the analyses of auto-covariance and auto-correlation function show that the flood's independence and randomness cannot be dismissed. Only for scenario B1 a significant dependence between the yearly flood maxima can be detected. The calculation of the Hurst coefficient H with 7 different methods shows that despite the present problem of a too short time series (n=100), there is a tendency to long-term persistence, as H lies between 0.5 and 0.7. Although there are graphically recognizable changes in the flood probabilities, these prove to be not statistically significant. Therefore, in conclusion, there is no evidence for an effect of 21st century climate change impact on the flood regime in the Fulda watershed area. This means that there should be no conflict when FFA is applied to 21st century flood extremes in this catchment. Of course, the results obtained in this study cannot be transferred to other hydrological systems.

  17. Residence times and age distributions of spring waters at the Semmering catchment area, Eastern Austria, as inferred from tritium, CFCs and stable isotopes.

    Science.gov (United States)

    Han, Liangfeng; Hacker, Peter; Gröning, Manfred

    2007-03-01

    The groundwater system in the mountainous area of Semmering, Austria, was studied by environmental tracers in several karst springs. The tracers used included stable isotopes ((18)O, (2)H), tritium ((3)H) and chlorofluorocarbons (CFCs). The tracers provided valuable information in regard to (1) the mean altitude of the spring catchment areas; (2) the residence time and age distribution of the spring waters; and (3) the interconnection of the springs to a sinkhole. The combination of the stable isotopic data and the topography/geology provided the estimates of the mean altitudes of the catchment areas. Based on the stable isotopic data the recharge temperature of the spring waters was estimated. The smoothing of precipitation's isotopic signal in spring discharge provided information on the minimum transit time of the spring waters. Due to short observation time, (3)H data alone cannot be used for describing the mean residence time of the karst waters. CFCs, though useful in recognizing the co-existence of young (post-1993) water with old (CFC-free) water, could not be used to resolve age distribution models. It is shown in this article, however, that the combined use of tritium and CFCs can provide a better assessment of models to account for different groundwater age distributions. In Appendix A, a simplified method for collecting groundwater samples for the analysis of CFCs is described. The method provides a real facilitation for fieldwork. Test data are given for this sampling method in regard to potential contamination by atmospheric CFCs.

  18. Soil and Water Resources and Land Sustainable Productivity in the Catchment Area with Intensive Management in Hilly Red Soil Regions,China

    Institute of Scientific and Technical Information of China (English)

    HUANG Dao-you; WANG Ke-lin; CHEN Gui-qiu; HUANG Min; PENG Ting-bo

    2004-01-01

    Taking an example of Majiayu Catchment Area (14.15 ha) in Taoyuan County of Hunan Province, the soil and water resources dynamics, fertility evolution characteristics and land productivity changing situation were studied. Fixed observation results from 1993 to 2002 showed that pools covering about 15% of total area could store up 10% of surface runoff, keep 78.1% of eroded soil and 65.4% of lost nutrients. The yearly ratio of interception and evapotranspiration in land, storage in pools and drainage was 7:2:1,which ensured the resources and nutrients equilibrium and a benign recycle in the catchment area system, and benefited the aquatic culture and helped to resist seasonal drought. Moreover, the results showed that soil erosion modulus decreased significantly,equal to or lower than soil loss tolerance (≤500 t km-2) in reddish yellow soil regions.Soil organic matter, total and available N content in sloping land, dryland and paddy field increased steadily (>10%); water storage enhanced by more than 20% in sloping land and dryland in drought season; crop production increased by more than 20%; and production of trees, fruits, tea and fish as well as land productivity increased yearly.

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

    Science.gov (United States)

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

    2009-06-01

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

  20. Chemical composition of natural waters of contaminated area: The case for the Imandra Lake catchment (the Kola Peninsula)

    Science.gov (United States)

    Evtyugina, Z. A.; Guseva, N. V.; Kopylova, J. G.; A, Vorobeva D.

    2016-03-01

    The study of the current chemical composition of natural waters in the eastern and western parts of the Imandra Lake catchment was performed using ion chromatography, potentiometry and inductively coupled plasma mass spectrometry. It was found that the content of trace elements in the surface water is considerably higher than that in the groundwater. The nickel and copper concentrations exceed the background levels over 19 and 2 times respectively in groundwater, and 175 and 61 times in the surface waters. These data show that the Severonikel influences negatively air and surface water.

  1. Using environmental isotopes in the study of the recharge-discharge mechanisms of the Yarmouk catchment area in Jordan

    Science.gov (United States)

    Salameh, Elias

    The recharge sources, the flow mechanisms and discharge areas of the different groundwater bodies underlying the Yarmouk River catchment area in Jordan, have, until now, not been adequately explained, although a wide range of hydrological, hydrogeological, and hydrochemical studies have been done. Along the Jordanian part of the catchment area of the Yarmouk River, groundwater issues from different aquifers with a variety of chemistries and types within the same aquifer and in between the different aquifers. Conventional recharge/discharge mechanisms, water balances and chemical analyses did not adequately explain the chemical variations and the different water types found in the area. Applying environmental isotopic tools combined with their altitude effects due to topographic variations (250-1,300 m a.s.l. within a distance of 20 km), and taking into consideration re-evaporation effects on the isotopic depletion and enrichment of rainwater, has greatly helped in understanding the recharge discharge mechanisms of the different aquifers. Precipitation along the highlands of an average of 600 mm/year is found to be depleted in its isotopic content of δO18 = -7.0 to -7.26 and δD = -32.2 to -33.28, whereas that of the Jordan Valley of 350 mm/year is highly enriched in isotopes with δO18 = -4.06 and δD = -14.5. The groundwater recharged along the highlands is depleted in isotopes (δO18 = -6, δD = -30), groundwater at the intermediate elevations is enriched (δO18 = -5, δD = -23) and that of the Jordan Valley aquifers containing meteoric water is highly enriched (δO18 -3.8, δD = -18). The deep aquifers in the Jordan Valley foothills are depleted in isotopes (δO18 -18 = -6, δD = -30) and resemble those of the highland aquifers. Only through using isotopes as a tool, were the sources of the different groundwater bodies and recharge and discharge mechanisms unambiguously explained. It was found that recharge takes place all over the study area and produces

  2. Is the impact of future climate change on hydro-climatic conditions significant? - A climate change study for an Eastern European catchment area.

    Science.gov (United States)

    Pavlik, Dirk; Söhl, Dennis; Bernhofer, Christian

    2014-05-01

    The future change of climatic conditions is, among others, closely linked to future hydrological changes. One important aspect of these issues is the question of future availability of water resources. A changed climatic water balance, as indicator for potential water availability, has far-reaching consequences for the water cycle, hydrological conditions, ecology, water management, the energy business, agriculture and forestry, and for anthropogenic use of the river. We generated regional climate projections via dynamic downscaling for the catchment area of the Western Bug river in the border area of Poland, Belarus, and Ukraine. The hydro-climatic conditions of the past and their projected future changes in the catchment were analyzed based on 2m-temperature, precipitation, potential evaporation and climatic water balance. Up to the end of the century, the used IPCC scenarios B1 and A2 lead to warming for each month in the long-term mean, with highest warming rates in winter. Instead, precipitation does not change in the long-term yearly mean. However, the intra-annual distribution of monthly precipitation sums shifts with an increase in winter and a strong decrease in summer. Combined, this leads to a changed climatic water balance with a stronger deficit in summer and a higher gain in winter. Particular in the south-eastern part of the catchment, the summer deficit cannot be compensated within the annual cycle. It raised the question: are these changes statistically significant and thus robust for use in further impact studies? Using a significance analysis, we found, that climatic changes in temperature, precipitation and potential evaporation and thus the climatic water balance change is most significant for scenario A2 from 2071 to 2100. The temperature changes are significant throughout the year. For the other variables changes are most significant in the late summer months (July, August, and September) and the winter months (December, January, and February

  3. Evolution of Hydrological Drought in Human Disturbed Areas: A Case Study in the Laohahe Catchment, Northern China

    Directory of Open Access Journals (Sweden)

    Yi Liu

    2016-01-01

    Full Text Available A case study on the evolution of hydrological drought in nonstationary environments is conducted over the Laohahe catchment in northern China. Using hydrometeorological observations during 1964–2009, meteorological and hydrological droughts are firstly analyzed with the threshold level method. Then, a comprehensive analysis on the changes within the catchment is conducted on the basis of hydrological variables and socioeconomic indices, and the whole period is divided into two parts: the undisturbed period (1964–1979 and the disturbed period (1980–2009. A separating framework is further introduced to distinguish droughts induced by different causes, that is, the naturalized drought and human-induced drought. Results showed that human activities are more inclined to play a negative role in aggravating droughts. Drought duration and deficit volume in naturalized conditions are amplified two to four times and three to eight times, respectively, when human activities are involved. For the two dry decades 1980s and 2000s, human activities have caused several consecutive drought events with rather long durations (up to 29 months. These results reflect the considerable impacts of human activities on hydrological drought, which could provide some theoretical support for local drought mitigation and water resources management.

  4. Hydrological Catchment Similarity Assessment in Geum River Catchments, Korea

    Science.gov (United States)

    Ko, Ara; Park, Kisoon; Lee, Hyosang

    2013-04-01

    Similarity measure of catchments is essential for regionalization studies, which provide in depth analysis in hydrological response and flood estimations at ungauged catchments. However, this similarity measure is often biased to the selected catchments and is notclearly explained in hydrological sense. This study applied a type of hydrological similarity distance measure-Flood Estimation Handbook to 25 Geum river catchments, Korea. Three Catchment Characteristics, Area (A)-Annual precipitation (SAAR)-SCS Curve Number (CN), are used in Euclidian distance measures. Furthermore, six index of Flow Duration Curve (ILow:Q275/Q185, IDrought:Q355/Q185, IFlood:Qmax/Q185, IAbundant:Q95/Q185, IFloodDuration:Q10/Q355 and IRiverRegime:Qmax/Qmin) are applied to clustering analysis of SPSS. The catchments' grouping of hydrological similarity measures suggests three groups: H1 (Cheongseong, Gidae, Bukil, Oksan, Seockhwa, Habgang and Sangyeogyo), H2 (Cheongju, Guryong, Ugon, Boksu, Useong and Seokdong) and H3 (Muju, Yangganggyo and YongdamDam). The four catchments (Cheoncheon, Donghyang, DaecheongDam and Indong) are not grouped in this study. The clustering analysis of FDC provides four Groups; CFDC1 (Muju, YongdamDam, Yangganggyo, DaecheongDam, Cheongseong, Gidae, Seokhwa, Bukil, Habgang, Cheongju, Oksan, Yuseong and Guryong), CFDC2 (Cheoncheon, Donghyang, Boksu, Indong, Nonsan, Seokdong, Ugon, Simcheon, Useong and Sangyeogyo), CFDC3 (Songcheon) and CFDC4 (Tanbu). The six catchments (out of seven) of H1 are grouped in CFDC1, while Sangyeogyo is grouped in CFDC2. The four catchments (out of six) of H2 are also grouped in CFDC2, while Cheongju and Guryong are grouped in CFDC1. The catchments of H3 are categorized in CFDC1. The authors examine the results (H1, H2 and H3) of similarity measure based on catchment physical descriptors with results (CFDC1 and CFDC2) of clustering based on catchment hydrological response. The results of hydrological similarity measures are supported by

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

    Science.gov (United States)

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

    2017-04-01

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

  6. Distribution, speciation, and risk assessment of selected metals in the gold and iron mine soils of the catchment area of Miyun Reservoir, Beijing, China.

    Science.gov (United States)

    Huang, Xingxing; Zhu, Yi; Ji, Hongbing

    2013-10-01

    In order to investigate the metal distribution, speciation, correlation and origin, risk assessment, 86 surface soil samples from the catchment area around the Miyun Reservoir, Beijing, including samples from gold and iron mine areas, were monitored for fractions of heavy metal and total contents. Most of the metal concentrations in the gold and iron mine soil samples exceeded the metal background levels in Beijing. The contents of most elements in the gold mine tailings were noticeably higher than those in the iron mine tailings. Geochemical speciation data of the metals showed that the residual fraction dominated most of the heavy metals in both mines. In both mine areas, Mn had the greatest the acid-soluble fraction (F1) per portion. The high secondary-phase fraction portion of Cd in gold mine samples indicated that there was a direct potential hazard to organisms in the tested areas. Multivariate analysis coupled with the contents of selected metals, showed that Hg, Pb, Cr, and Ni in gold mine areas represented anthropogenic sources; Cd, Pb, and Cr in iron mine areas represented industrial sources. There was moderate to high contamination of a few metals in the gold and iron soil samples, the contamination levels were relatively higher in gold mine than in iron mine soils.

  7. REXPO: A catchment model designed to understand and simulate the loss dynamics of plant protection products and biocides from agricultural and urban areas

    Science.gov (United States)

    Wittmer, I. K.; Bader, H.-P.; Scheidegger, R.; Stamm, C.

    2016-02-01

    During rain events, biocides and plant protection products are transported from agricultural fields but also from urban sources to surface waters. Originally designed to be biologically active, these compounds may harm organisms in aquatic ecosystems. Although several models allow either urban or agricultural storm events to be predicted, only few combine these two sources, and none of them include biocide losses from building envelopes. This study therefore aims to develop a model designed to predict water and substance flows from urban and agricultural sources to surface waters. We developed a model based on physical principles for water percolation and substance flow including micro- (also called matrix-) and macropore-flows for the agricultural areas together with a model representing sources, sewer systems and a wastewater treatment plant for urban areas. In a second step, the combined model was applied to a catchment where an extensive field study had been conducted. The modelled and measured discharge and compound results corresponded reasonably well in terms of quantity and dynamics. The total cumulative discharge was only slightly lower than the total measured discharge (factor 0.94). The total modelled losses of the agriculturally used herbicide atrazine were slightly lower (∼25%) than the measured losses when the soil pore water distribution coefficient (describing the partition between soil particles and pore water) (Kd) was kept constant and slightly higher if it was increased with time. The modelled urban losses of diuron from facades were within a factor of three with respect to the measured values. The results highlighted the change in importance of the flow components during a rain event from urban sources during the most intensive rain period towards agricultural ones over a prolonged time period. Applications to two other catchments, one neighbouring and one on another continent showed that the model can be applied using site specific data for

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

    Science.gov (United States)

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

    2015-04-01

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

  9. Physical-chemical modeling of elements' behavior in mixing sea and fresh waters of minor rivers in the White Sea catchment area.

    Science.gov (United States)

    Maksimova, Victoria V; Mazukhina, Svetlana I; Cherepanova, Tatiana A; Gorbacheva, Tamara T

    2017-07-29

    The physical-chemical stage of marginal filters in minor rivers of the White Sea catchment area by the example of the Umba River, flowing to Kandalaksha Gulf, has been explored. Application of the method of physical-chemical modeling on the basis of field data allowed establishing migration forms of a number of elements in the "river-sea" system and deposition of solid phases when mixing waters. The mixing of river and sea water is accompanied by the sedimentation of predominantly goethite, hydromuscovite, and hydroxylapatite. Sediments in mixing river and sea waters were found to be mainly composed by goethite, hydromuscovite, and hydroxylapatite. The research has added to the knowledge of the role of the abiotic part in the marginal filters of small rivers in the Arctic.

  10. Is organizational change associated with increased rates of readmission to general hospital in suicide attempters? A 10-year prospective catchment area study.

    Science.gov (United States)

    Mehlum, Lars; Jørgensen, Trond; Diep, Lien My; Nrugham, Latha

    2010-01-01

    The objective of this study was to examine predictors for readmissions in patients admitted to a general hospital emergency ward for suicide attempts before and after organizational changes potentially affecting the chain of care. Socio-demographic and clinical variables were collected by clinicians from 1997 thru 2007. Data from the periods before and after 2004--when the hospital changed its catchment area--were compared. A substantial increase in readmission rates in the period after the organizational change was observed. This increase was not associated with any of the socio-demographic or clinical patient characteristics. Although no causal connection can be inferred, the observed association between organizational change and readmission rates could indicate that established post-discharge care systems for suicide attempters may be vulnerable to such change.

  11. Threshold Value Research about Catchment Area of Drainage Network of Hetao Irrigated Area%河套灌区排水网络集水面积闽值研究

    Institute of Scientific and Technical Information of China (English)

    周钧迪; 马锦; 宋密; 程一平; 张涛

    2012-01-01

    流域数字水系网络提取的精度,通常与所使用的数字高程图(DEM)的精度和集水面积阈值的大小有关。在给定的DEM图上,数字水系的精度基本上取决于集水面积阈值的设置。首先介绍了几种确定阈值大小的方法,然后应用其中的“河网密度”法来对河套灌区的排干沟的水系网络进行提取。结果表明,该方法能很好地应用于灌区水系网络的合理提取。%The accuracy extraction of basins stream cision and the the threshold value of catchment area. ital stream digital network basically depends on how digital network usually is related to the DEM pre- In a givend DEM map, the precision of the dig- to set the threshold value of the catchment area.This paper first introduces several determine method of t the threshold value , then apply the "river network density" method to the extraction of drainage network for hetao irrigated area . The results show that the method can be used in reasonable network extraction for drainage network of irrigation.

  12. Determination of The Water Catchment Area in Semarang City Using a Combination of Object Based Image Analysis (OBIA) Classification, InSAR and Geographic Information System (GIS) Methods Based On a High-Resolution SPOT 6 Image and Radar Imagery

    Science.gov (United States)

    Prasetyo, Yudo; Ardi Gunawan, Setyo; Maksum, Zia Ul

    2016-11-01

    Semarang is the biggest city in central Java-Indonesia which has a rapid and massive infrastructure development nowadays. In order to control water resources and flood, the local goverment has been built east and west flood canal in Kaligarang and West Semarang River. One of main problem in Semarang city is the lack of fresh water in dry season because ground water is not rechargeable well. Rechargeable groundwater ability depends on underground water recharge rate and catchment area condition. The objective of the study is to determine condition and classification of water catchment area in Semarang city. The catchment area conditions will be determine by five parameters as follows soil type, land use, slope, ground water potential and rainfall intensity. In this study, we use three methods approach to solve the problem which is segmentation classification to acquire land use classification from high resolution imagery using nearest neighborhood algorithm, Interferometric Synthetic Aperture Radar (SAR) to derive DTM from SAR Imagery and multi criteria weighting and spatial analysis using GIS method. There are three types optical image (ALOS PRISM, SPOT-6 and ALOS PALSAR) to calculate water catchment area condition in Semarang city. For final result, this research will divide the water catchment into six criteria as follows good, naturally normal, early critical, a little bit critical, critical and very critical condition. The result shows that water catchment area condition is in an early critical condition around 2607,523 Ha (33,17 %), naturally normal condition around 1507,674 Ha (19,18 %), a little bit critical condition around 1452,931 Ha (18,48 %), good with 1157,04 Ha (14,72 %), critical with 1058,639 Ha (13,47 %) and very critical with 75,0387 Ha (0,95 %). The distribution of water catchment area conditions in West and East Flood Canal have an irreguler pattern. In northern area of watershed consists of begin to critical, naturally normal and good condition

  13. Spatial Analysis in Determination Of Flood Prone Areas Using Geographic Information System and Analytical Hierarchy Process at Sungai Sembrong's Catchment

    Science.gov (United States)

    Bukari, S. M.; Ahmad, M. A.; Wai, T. L.; Kaamin, M.; Alimin, N.

    2016-07-01

    Floods that struck Johor state in 2006 and 2007 and the East Coastal in 2014 have triggered a greatly impact to the flood management here in Malaysia. Accordingly, this study conducted to determine potential areas of flooding, especially in Batu Pahat district since it faces terrifying experienced with heavy flood. This objective is archived by using the application of Geographic Information Systems (GIS) on study area of flood risk location at the watershed area of Sungai Sembrong. GIS functions as spatial analysis is capable to produce new information based on analysis of data stored in the system. Meanwhile the Analytical Hierarchy Process (AHP) was used as a method for setting up in decision making concerning the existing data. By using AHP method, preparation and position of the criteria and parameters required in GIS are neater and easier to analyze. Through this study, a flood prone area in the watershed of Sungai Sembrong was identified with the help of GIS and AHP. Analysis was conducted to test two different cell sizes, which are 30 and 5. The analysis of flood prone areas were tested on both cell sizes with two different water levels and the results of the analysis were displayed by GIS. Therefore, the use of AHP and GIS are effective and able to determine the potential flood plain areas in the watershed area of Sungai Sembrong.

  14. Combining AHP with GIS for landfill site selection: a case study in the Lake Beyşehir catchment area (Konya, Turkey).

    Science.gov (United States)

    Sener, Sehnaz; Sener, Erhan; Nas, Bilgehan; Karagüzel, Remzi

    2010-11-01

    Landfills are the most common method for the disposal of municipal solid waste (MSW) in Turkey. However, determining the location of landfill sites is a difficult and complex process because it must combine social, environmental and technical parameters. Additionally, it depends on several criteria and regulations. The main objective of this study was to select of a landfill site for the Lake Beyşehir catchment area. The Beyşehir Lake is the largest freshwater lake and drinking water reservoir in Turkey, but there is no controlled landfill site in the region. Therefore, the landfill site should be determined such that the lake is protected. To determine the most suitable landfill site, an analytical hierarchy process (AHP) was combined with a geographic information system (GIS) to examine several criteria, such as geology/hydrogeology, land use, slope, height, aspect and distance from settlements, surface waters, roads, and protected areas (ecologic, scientific or historic). Each criterion was evaluated with the aid of AHP and mapped by GIS. Data were assorted into four suitability classes within the study area, i.e., high, moderate, low and very low suitability areas, which represented 3.24%, 7.55%, 12.70% and 2.81%, of the study area, respectively. Additionally, 73.70% was determined to be completely unsuitable for a landfill site. As a result, two candidate landfill sites are suggested and discussed. The final decision for landfill site selection will require more detailed field studies. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Flash floods and debris flow in the city area of Messina, north-east part of Sicily, Italy in October 2009: the case of the Giampilieri catchment

    Directory of Open Access Journals (Sweden)

    G. T. Aronica

    2012-05-01

    Full Text Available This paper concerns the analysis of the 1 October 2009 flash flood and debris flow event caused by a very intense rainfall concentrated over the Messina area. The storm caused severe flash floods in many villages around the city of Messina, such as Giampilieri, Scaletta Zanclea, Altolia Superiore and Molino, with 38 casualties and significant damages to property, buildings, roads and bridges estimated close to 550 million Euro. The main focus of this work is to perform a post event analysis, putting together available meteorological and hydrological data in order to get better insight into temporal and spatial variability of the rain storm, the soil moisture conditions and the consequent flash flood in the Giampilieri catchment. The event was investigated using observed data from a raingauge network. Statistical analysis using GEV distribution was performed and rainfall return period (storm severity was estimated. Further, measured rainfall data and rainfall-runoff modelling were used to estimate soil moisture conditions, to analyse the hydrological behaviour and to reconstruct flood hydrograph. With the help of GIS technology and particularly spatial analysis, the volume of debris which has gone down into the Giampilieri village was also calculated. GIS maps with landslide and material deposit areas were produced and analysed.

  16. Integrated modeling of agricultural scenarios (IMAS) to support pesticide action plans: the case of the Coulonge drinking water catchment area (SW France).

    Science.gov (United States)

    Vernier, Françoise; Leccia-Phelpin, Odile; Lescot, Jean-Marie; Minette, Sébastien; Miralles, André; Barberis, Delphine; Scordia, Charlotte; Kuentz-Simonet, Vanessa; Tonneau, Jean-Philippe

    2017-03-01

    Non-point source pollution is a cause of major concern within the European Union. This is reflected in increasing public and political focus on a more sustainable use of pesticides, as well as a reduction in diffuse pollution. Climate change will likely to lead to an even more intensive use of pesticides in the future, affecting agriculture in many ways. At the same time, the Water Framework Directive (WFD) and associated EU policies called for a "good" ecological and chemical status to be achieved for water bodies by the end of 2015, currently delayed to 2021-2027 due to a lack of efficiency in policies and timescale of resilience for hydrosystems, especially groundwater systems. Water managers need appropriate and user-friendly tools to design agro-environmental policies. These tools should help them to evaluate the potential impacts of mitigation measures on water resources, more clearly define protected areas, and more efficiently distribute financial incentives to farmers who agree to implement alternative practices. At present, a number of reports point out that water managers do not use appropriate information from monitoring or models to make decisions and set environmental action plans. In this paper, we propose an integrated and collaborative approach to analyzing changes in land use, farming systems, and practices and to assess their effects on agricultural pressure and pesticide transfers to waters. The integrated modeling of agricultural scenario (IMAS) framework draws on a range of data and expert knowledge available within areas where a pesticide action plan can be defined to restore the water quality, French "Grenelle law" catchment areas, French Water Development and Management Plan areas, etc. A so-called "reference scenario" represents the actual soil occupation and pesticide-spraying practices used in both conventional and organic farming. A number of alternative scenarios are then defined in cooperation with stakeholders, including socio

  17. Assessment of sediment sources throughout the proglacial area of a small Arctic catchment based on high-resolution digital elevation models

    Science.gov (United States)

    Kociuba, Waldemar

    2017-06-01

    The article presents calculations of quantitative modifications of the morphology of selected subsystems of a glacial valley through: (i) identification of the spatial distribution of important sources of sediment, (ii) assessment of the spatiotemporal variety of sediment volume and landform morphology, and (iii) assessment of the role of particular subsystems in sediment distribution. The study involved a comparison of the results of field measurements from 2010 to 2013 performed in the Scott Glacier catchment (10.1 km2) in NW Wedel Jarlsberg Land (Spitsbergen). The assessment of the landform surface changes was performed by means of a precise Terrestrial Laser Scanning (TLS) survey. The applied field and post-processing techniques for oblique laser scanning permitted the acquisition of digital elevation data at a resolution 0.01 m and density > 500 pt m- 2. This allowed the development of a detailed terrain model, and balancing spatial quantitative changes in six research test areas (10,000 m2) located within two subsystems of the catchment in a cascade arrangement. In the alluvial valley-floor subsystem, the survey covered: 1) the glacier terminus, 2) the intramarginal outwash plain, 3) the extramarginal braid-plain and 4) the alluvial fan, and in the slope subsystem: 5) the erosional-depositional slope in the gorge through terminal moraines, and 6) the solifluction slope. Three zones differing in terms of the spatiotemporal dynamics of geomorphic processes were distinguished within the two analysed valley subsystems. In the valley floor subsystem, these are: (i) the zone of basic supply (distribution throughout the melting season) and (ii) the redeposition zone (distribution particularly during floods), and in the slope subsystem: (iii) zone of periodical supply (distributed mainly in periods of increased precipitation and rapid increases in temperature in summer and during snow avalanches in winter). The glacier and the landforms of the channel and valley

  18. The Achievement of a Decentralized Water Management Through Stakeholder Participation: An Example from the Drôme River Catchment Area in France (1981-2008)

    Science.gov (United States)

    Comby, Emeline; Le Lay, Yves-François; Piégay, Hervé

    2014-11-01

    Different water Acts (e.g., the European Water Framework Directive) and stakeholders involved in aquatic affairs have promoted integrated river basin management over recent decades. However, few studies have provided feedback on these policies. The aim of the current article is to fill this gap by exploring how local newspapers reflect the implementation of a broad public participation within a catchment of France known for its innovation with regard to this domain. The media coverage of a water management strategy in the Drôme watershed from 1981 to 2008 was investigated using a content analysis and a geographic information system. We sought to determine what public participation and decentralized decision-making can be in practice. The results showed that this policy was integrated because of its social perspective, the high number of involved stakeholders, the willingness to handle water issues, and the local scale suitable for participation. We emphasized the prominence of the watershed scale guaranteed by the local water authority. This area was also characterized by compromise, arrangements, and power dynamics on a fine scale. We examined the most politically engaged writings regarding water management, which topics of each group emphasized, and how the groups agreed and disagreed on issues based on their values and context. The temporal pattern of participation implementation was progressive but worked by fits and starts.

  19. Nonmedical Opioid Pain Relievers and All-Cause Mortality: A 27-Year Follow-Up From the Epidemiologic Catchment Area Study

    Science.gov (United States)

    Hu, Hui; Smallwood, Bryan A.; Anthony, James C.; Wu, Li-Tzy; Eaton, William W.

    2016-01-01

    Objectives. We investigated whether nonmedical opioid pain reliever use is associated with higher mortality in the general US population. Methods. We assessed the history of nonmedical opioid pain reliever use among 9985 people interviewed at baseline of the Epidemiologic Catchment Area Program initiated in 1981 to 1983 in Baltimore, Maryland; St. Louis, Missouri; and Durham, North Carolina. We linked the data with the National Death Index through 2007. Results. Nonmedical opioid pain reliever use was 1.4%. Compared with no nonmedical drug use, mortality was increased for nonmedical opioid pain reliever use (hazard ratio [HR] = 1.60; 95% confidence interval [CI] = 1.01, 2.53) or nonmedical use of other drugs (HR = 1.31; 95% CI = 1.07, 1.62). Mortality was also higher for males and for those beginning nonmedical opioid pain reliever use before aged 15 years. Conclusions. A history of nonmedical opioid pain reliever use was associated with increased mortality, in particular for males and early onset users. PMID:26691106

  20. The construction of synthetic maps of groundwater vulnerability on the example of catchment area of Žilůvky stream

    Directory of Open Access Journals (Sweden)

    Kristýna Kubová

    2007-01-01

    Full Text Available The term “vulnerability of groundwater to contamination” was introduced by French hydrogeologist J. Margat in the late 1960s. The idea of describing the degree of vulnerability of groundwater to contaminants as a function of hydrogeological conditions by means of maps was conceived to show that the protection provided by the natural environment varies at different locations. Groundwater vulnerability maps belong to category of special-purpose environmental maps and introduce one of the possible tool to solve groundwater protection. The synthetic map of relevant catchment area of Žilůvky stream was composed in the program ArcGIS as a intersection between 4 partial maps: the map of soil character according to infiltration capability, the map of geological structure according to permeability, the map of unsaturated zone potency and the map of karst phenomens, springs and boreholes localization. The final map was presented in 4 variants A – D according to meaning of layers which have the influence on groundwater vulnerability.

  1. The effect of social networks and social support on mental health services use, following a life event, among the Baltimore Epidemiologic Catchment Area cohort.

    Science.gov (United States)

    Maulik, Pallab K; Eaton, William W; Bradshaw, Catherine P

    2011-01-01

    The study examined the association between life events and mental health services use, accounting for social networks and social support. Main and stress-buffering effects were estimated using longitudinal data from the Baltimore Epidemiologic Catchment Area cohort (1,920 participants in 1993-1996, of whom 1,071 were re-interviewed in 2004-2005). Following a life event, the odds of using general medical services were increased by almost 50% when there was increased social support from spouse/partner (referral function). The odds of using mental health services within general health setup were reduced by 60% when there was increased support from relatives (stress-reduction function). Increased social support from friends and relatives was associated with a 40-60% decreased odds of using specialty psychiatric services after experiencing different life events (stress-reduction function). Overall, social support rather than social networks were more strongly associated with increased mental health service use following a life event. The implications for service delivery and program development are discussed.

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

    OpenAIRE

    H. Guan; Love, A. J.; Simmons, C.T.; J. Hutson; Ding, Z.

    2010-01-01

    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 a...

  3. Space-time modeling of catchment scale drought characteristics

    NARCIS (Netherlands)

    Tallaksen, L.; Hisdal, H.; Lanen, van H.A.J.

    2009-01-01

    Drought may affect all components of the water cycle and covers commonly a large part of the catchment area. This paper examines drought propagation at the catchment scale using spatially aggregated drought characteristics and illustrates the importance of catchment processes in modifying the

  4. Land Suitability Assessment in the Catchment Area of Four Southwestern Atlantic Coastal Lagoons: Multicriteria and Optimization Modeling

    Science.gov (United States)

    Rodriguez-Gallego, Lorena; Achkar, Marcel; Conde, Daniel

    2012-07-01

    In the present study, a land suitability assessment was conducted in the basin of four Uruguayan coastal lagoons (Southwestern Atlantic) to analyze the productive development while minimizing eutrophication, biodiversity loss and conflicts among different land uses. Suitable land for agriculture, forest, livestock ranching, tourism and conservation sectors were initially established based on a multi-attribute model developed using a geographic information system. Experts were consulted to determine the requirements for each land use sector and the incompatibilities among land use types. The current and potential conflicts among incompatible land use sectors were analyzed by overlapping land suitability maps. We subsequently applied a multi-objective model where land (pixels) with similar suitability was clustered into "land suitability groups", using a two-phase cluster analysis and the Akaike Information Criterion. Finally, a linear programming optimization procedure was applied to allocate land use sectors into land suitable groups, maximizing total suitability and minimizing interference among sectors. Results indicated that current land use overlapped by 4.7 % with suitable land of other incompatible sectors. However, the suitable land of incompatible sectors overlapped in 20.3 % of the study area, indicating a high potential for the occurrence of future conflict. The highest competition was between agriculture and conservation, followed by forest and agriculture. We explored scenarios where livestock ranching and tourism intensified, and found that interference with conservation and agriculture notably increased. This methodology allowed us to analyze current and potential land use conflicts and to contribute to the strategic planning of the study area.

  5. Land suitability assessment in the catchment area of four Southwestern Atlantic coastal lagoons: multicriteria and optimization modeling.

    Science.gov (United States)

    Rodriguez-Gallego, Lorena; Achkar, Marcel; Conde, Daniel

    2012-07-01

    In the present study, a land suitability assessment was conducted in the basin of four Uruguayan coastal lagoons (Southwestern Atlantic) to analyze the productive development while minimizing eutrophication, biodiversity loss and conflicts among different land uses. Suitable land for agriculture, forest, livestock ranching, tourism and conservation sectors were initially established based on a multi-attribute model developed using a geographic information system. Experts were consulted to determine the requirements for each land use sector and the incompatibilities among land use types. The current and potential conflicts among incompatible land use sectors were analyzed by overlapping land suitability maps. We subsequently applied a multi-objective model where land (pixels) with similar suitability was clustered into "land suitability groups", using a two-phase cluster analysis and the Akaike Information Criterion. Finally, a linear programming optimization procedure was applied to allocate land use sectors into land suitable groups, maximizing total suitability and minimizing interference among sectors. Results indicated that current land use overlapped by 4.7 % with suitable land of other incompatible sectors. However, the suitable land of incompatible sectors overlapped in 20.3 % of the study area, indicating a high potential for the occurrence of future conflict. The highest competition was between agriculture and conservation, followed by forest and agriculture. We explored scenarios where livestock ranching and tourism intensified, and found that interference with conservation and agriculture notably increased. This methodology allowed us to analyze current and potential land use conflicts and to contribute to the strategic planning of the study area.

  6. PEMODELAN DAERAH TANGKAPAN AIR WADUK KELILING DENGAN MODEL SWAT (Keliling Reservoir Catchment Area Modeling Using SWAT Model

    Directory of Open Access Journals (Sweden)

    Teuku Ferijal

    2015-05-01

    Full Text Available This study aimed to model watershed area of Keliling Reservoir using SWAT model. The reservoir is located in Aceh Besar District, Province of Aceh. The model was setup using 90m x 90m digital elevation model, land use data extracted from remote sensing data and soil characteristic obtained from laboratory analysis on soil samples. Model was calibrated using observed daily reservoir volume and the model performance was analyzed using RMSE-observations standard deviation ratio (RSR, Nash-Sutcliffe efficiency (NSE and percent bias (PBIAS. The model delineated the study area into 3,448 Ha having 13 subwatersheds and 76 land units (HRUs. The watershed is mostly covered by forest (53% and grassland (31%. The analysis revealed the 10 most sensitive parameters i.e. GW_DELAY, CN2, REVAPMN, ALPHA_BF, SOL_AWC, GW_REVAP, GWQMN, CH_K2 and ESCO. Model performances were categorized into very good for monthly reservoir volume with ENS 0.95, RSR 0.23, and PBIAS 2.97. The model performance decreased when it used to analyze daily reservoir inflow with ENS 0.55, RSR 0.67, and PBIAS 3.46. Keywords: Keliling Reservoir, SWAT, Watershed   ABSTRAK Penelitian ini bertujuan untuk untuk memodelkan daerah tangkapan air Waduk Keliling dengan menggunakan Model SWAT. Waduk Keliling terletak di Kabupaten Aceh Besar, Propinsi Aceh. Dalam penelitian ini Model SWAT dikembangkan berdasarkan data digital elevasi model resolusi 90 m x90 m, tata guna lahan yang diperoleh dari intepretasi citra satelit dan data soil dari hasil analisa sampel tanah yang diperoleh di daerah penelitian. Model dikalibrasi dengan data volume waduk dan kinerja model dianalisa menggunakan parameter rasio akar rata-rata kuadrat error dan standard deviasi observasi (RSR, efesiensi Nash-Sutcliffe (NSE dan persentase bias (PBIAS. Hasil deleniasi untuk daerah penelitian menghasilkan suatu DAS dengan luas 3,448 Ha dan memiliki 13 Sub DAS yang dikelompokkan menjadi 76 unit lahan. Sebagian besar wilayah study

  7. Assessment of the predisposing factors for shallow landslides activation in terraced areas: the case of the Rupinaro catchment, Liguria (northwestern Italy).

    Science.gov (United States)

    Cignetti, Martina; Godone, Danilo; Giordan, Daniele

    2017-04-01

    The shallow landslides occurrence is strongly correlated with climatic conditions and environmental settings. In the Liguria region (northwestern Italy), the landscape presents an ancient human intervention represented by terraces and, in the last century, by a general overbuilding, both in the few flat areas and in the steep slope hinterland. From the twentieth century, the progressive abandonment of agriculture generated a lack of maintenance of terraced areas, which associated to the urban and the road net development, supported the slope susceptibility to instability. This makes the assessment of the predisposing factors for shallow landslides a multidisciplinary task, combining natural and man-made issues. In this work, we try to define all the main predisposing factors of the Rupinaro catchment (southeast Liguria). We operate starting from a high-resolution Digital Terrain Model (DTM) supplied by an airborne LiDAR survey carried out after the autumn 2014 rainfall events. From this DTM, we mapped a total amount of 96 landslides in the study area. Then, we implemented a classification methodology based on a simple parametric score. In GIS environment we overlaid several layers: i) lithological and hydrogeological map, ii) slope iii) aspect, iv) the land use information, available by the CORINE land cover, and iv) the presence of terraces. Each spatial data was than reclassified according a numerical code. The sum, by raster math, of these factors provided an overall score raster for the entire basin. This method allows the characterization of the entire watershed, gathering all the predisposing factors for the shallow landslides activation. A categorization of the landslides area mapped from the DTM and stored in a vector layer has been made. In particular, we estimated the most frequent code within each landslide polygon, obtaining a representative data of the most influential factors that triggered shallow landslides. The results showed the prevalent

  8. Biodegradation of free cyanide by bacterial species isolated from cyanide-contaminated artisanal gold mining catchment area in Burkina Faso.

    Science.gov (United States)

    Razanamahandry, Lovasoa Christine; Andrianisa, Harinaivo Anderson; Karoui, Hela; Kouakou, Koffi Marcelin; Yacouba, Hamma

    2016-08-01

    Soil and water samples were collected from a watershed in Burkina Faso where illegal artisanal gold extraction using cyanidation occurs. The samples were used to evaluate cyanide contamination and the presence of cyanide degrading bacteria (CDB). Free cyanide (F-CN) was detected in all samples, with concentrations varying from 0.023 to 0.9 mg kg(-1), and 0.7-23 μg L(-1) in the soil and water samples, respectively. Potential CDB also were present in the samples. To test the effective F-CN degradation capacity of the isolated CDB species, the species were cultivated in growth media containing 40, 60 or 80 mg F-CN L(-1), with or without nutrients, at pH 9.5 and at room temperature. More than 95% of F-CN was degraded within 25 h, and F-CN degradation was associated with bacterial growth and ammonium production. However, initial concentrations of F-CN higher than 100 mg L(-1) inhibited bacterial growth and cyanide degradation. Abiotic tests showed that less than 3% of F-CN was removed by volatilization. Thus, the degradation of F-CN occurred predominately by biological mechanisms, and such mechanisms are recommended for remediation of contaminated soil and water. The bacteria consortium used in the experiment described above exist in a Sahelian climate, which is characterized by a long hot and dry season. Because the bacteria are already adapted to the local climate conditions and show the potential for cyanide biodegradation, further applicability to other contaminated areas in West Africa, where illegal gold cyanidation is widespread, should be explored. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Past and future impact of North Atlantic teleconnection patterns on the hydroclimate of the Caspian catchment area in CESM1.2.2 and observations

    Science.gov (United States)

    Nandini, Sri

    2017-04-01

    The Caspian Sea level has undergone dramatic variations of more than 3 m during the past century with important implications for the life of coastal people, economy and the ecosystem. The origin of these variations as well as future changes in the Caspian water budget are still a matter of debate. In this study, we examine the influence of the major seasonal North Atlantic teleconnection patterns, the North Atlantic Oscillation (NAO), the East Atlantic pattern (EA), the Scandinavian pattern (SCA), and the North Sea Caspian Pattern (NCP), on Caspian hydroclimate variability from 1850-2000 CE. Numerical experiments at different atmospheric grid resolutions (2° and 1°) are carried out with the coupled Community Earth System Model (CESM1.2.2). We test model skills under different resolutions through validation against observational data by various statistical methods (Empirical Orthogonal Functions, Taylor diagrams, linear regressions and Spearman rank correlation). Results reveal the strongest simulated signal in winter (DJF) with high explained variances for 1° CESM1.2.2 NAO (39%) and EA (15.7%), similar to observational data. The model is unable to reproduce the SCA pattern in the third EOF, which is found in the observations. The modelled NAO has a strong influence on winter temperature and rainfall over the Caspian catchment area. A strong winter NCP induces above-average 2-meter temperatures over north Caspian region and lower-than-normal precipitation over the eastern Caspian sea. Our study suggests that the 1° version of CESM1.2.2 (with CAM5 atmosphere physics) shows adequate performance with respect to teleconnection maps during the historical period. Lastly, 1° model climate projections (2005-2100 CE) are performed with different Representative Concentration Pathways (RCP 4.5 and RCP 8.5) to examine potential changes in the teleconnection patterns and their influence on the Caspian region.

  10. An efficient method for applying a differential equation to deriving the spatial distribution of specific catchment area from gridded digital elevation models

    Science.gov (United States)

    Qin, Cheng-Zhi; Ai, Bei-Bei; Zhu, A.-Xing; Liu, Jun-Zhi

    2017-03-01

    Deriving the spatial distribution of specific catchment area (SCA) from a gridded digital elevation model (DEM) is one of the most important issues in digital terrain analysis. Conventional methods usually estimate SCA for each cell using a flow direction algorithm, but the results obtained are often unsatisfactory. Recently, Gallant and Hutchinson (2011, Water Resources Research, 47(5), W05535) proposed a differential equation which quantifies the change of SCA along a slope line, and thus the numerical solution of SCA at any point on a surface can be calculated accurately by integrating the differential equation. However, obtaining the numerical SCA solution based on this differential equation is so computationally intensive that it is too time-consuming to use it to derive the overall SCA spatial distribution from a gridded DEM. In this study, we developed a parallel algorithm based on OpenMP to make the numerical SCA solution based on Gallant and Hutchinson (2011)'s differential equation practical to derive the spatial distribution of SCA from a gridded DEM. Experiments based on two artificial surfaces with theoretical SCA and a more complex real terrain surface demonstrated that the proposed parallel algorithm obtained satisfactory acceleration performance and a much lower error than the MFD-md algorithm, which is a representative of conventional grid-based flow direction algorithms. Due to the speedup effects of the proposed parallel algorithm, we analyzed the effects of the DEM grid size and integration step length on the numerical SCA solution in detailed experiments. The experimental results suggested that the proposed algorithm performed best normally at the resolution of 5 m. A step ratio of 0.5 is suitable in applications of the proposed parallel algorithm.

  11. Analysis of flow signatures and catchment similarity indices for catchment classification in Yesilirmak Basin

    Science.gov (United States)

    Soyugur, Batuhan; Yilmaz, Koray K.

    2017-04-01

    Catchment classification schemes aim to identify groups of hydrologically similar catchments to enable a mapping between catchment physical characteristics and hydro-climatic conditions with the catchment functioning. This mapping, together with the quantified uncertainties, potentially facilitates improved process understanding, transfer of this understanding to ungauged catchments, model parameter regionalization and hence improve operational applications and watershed management. Although many studies focusing on the topic of catchment classification exist in the literature, there is yet no general consensus on the number and type of similarity metrics that should be included in such analysis. The aim of this study is to first carefully derive hydrologically relevant similarity metrics from catchment physical (elevation, area, slope, geology, soils, land use etc.), climatic (seasonality, temperature, aridity index etc.) and hydrologic response characteristics (flow signatures) and then utilize Affinity Propagation clustering algorithm to determine the optimal number of groupings based on individual as well as a combination of these similarity metrics. The study area is comprised of 24 sub-catchments located in the Yesilirmak Basin, Turkey, where daily streamflow and meteorological variables are available. The metrics that are based on flow signatures summarize a number of behavioral functions of the watershed system including those derived from flow duration curve (overall water balance, vertical redistribution) as well as temporal redistribution of flow (seasonality etc.). Our initial results indicated that inclusion of information on geology and seasonality (climate and flow) appears to be promising in delineating the hydrologic functioning of the catchments.

  12. Assessment of Diversity, Distribution, Conservation Status and Preparation of Management Plan for Medicinal Plants in the Catchment Area of Parbati Hydroelectric Project Stage -Ⅲ in Northwestern Himalaya

    Institute of Scientific and Technical Information of China (English)

    S.S. Samant; Jitendra S. Butola; Aman Sharma

    2007-01-01

    ligulata may be considered as threatened species due to their over exploitation for trade. 90 species are propagated by seeds, 8 species by seeds and rhizomes/roots/tubers,4 species by seeds and cuttings, and 2 species by sori.A management plan for the cultivation and conservation of the medicinal plants in the dam submergence area, and the commercially viable medicinal plants with high value in the catchment area is suggested.

  13. Biofuels from the forest. A study of environmental impacts and economy of different uses; Biobraensle fraan skogen. En studie av miljoekonsekvenser och ekonomi foer olika anvaendningar

    Energy Technology Data Exchange (ETDEWEB)

    Ekstroem, Clas; Amnell, Goesta; Anheden, Marie; Eidensten, Lars; Kirkegaard, Gunilla [Vattenfall Utveckling AB (Sweden)

    2002-04-01

    in neighbouring countries. In some of these cases, bioenergy would not imply any additional cost in comparison with the use of electricity produced by coal condensing plants. In most other cases the estimated additional costs will not be higher than about 60 SEK/tonne reduced CO{sub 2} emissions (up to 90 SEK/MWh electricity). If bioenergy in cases with additional costs is to replace electricity from coal condensing plants it is necessary to place a price on the CO{sub 2} emissions by coal power stations and/or submit them to carbon dioxide taxation. This is not the case today. Pellet boilers in multi-family houses can utilise considerable amounts of forest biofuel and provide heating at lower costs than electric boilers. District heating and cogeneration of power and district heating can also utilise large volumes of forest biofuel (up to 20 TWh resulting in more than 12 Mtonnes/year reduced CO{sub 2} emissions) at low added costs (about 60 SEK/tonne reduced CO{sub 2} emissions corresponding to 20-40 SEK/MWh district heating) in comparison with fossil alternatives. Emissions of other air pollutants can then more easily be minimised and will occur further from built-up areas. The amount of electricity that can be produced from forest biofuel at these low added costs in comparison with fossil alternatives is restricted by the level of district-heating production. Today the power transmission systems permit only limited exports of electrical power, and consequently important reductions in CO{sub 2} emissions can be achieved at low cost if electricity from biofuel-fired cogeneration plants, that cannot be exported, is used by new heat pumps in villas. This would also give lower emissions of other air pollutants in urban areas than if pellets or oil were used to fire the villa boilers. Heat pumps and pellet boilers will be the most favourable forest biofuel based heating alternative for villas heated by water radiators. Heat pumps give greater reductions in CO{sub 2

  14. Biofuels from the forest. A study of environmental impacts and economy of different uses; Biobraensle fraan skogen. En studie av miljoekonsekvenser och ekonomi foer olika anvaendningar

    Energy Technology Data Exchange (ETDEWEB)

    Ekstroem, Clas; Amnell, Goesta; Anheden, Marie; Eidensten, Lars; Kirkegaard, Gunilla [Vattenfall Utveckling AB (Sweden)

    2002-04-01

    in neighbouring countries. In some of these cases, bioenergy would not imply any additional cost in comparison with the use of electricity produced by coal condensing plants. In most other cases the estimated additional costs will not be higher than about 60 SEK/tonne reduced CO{sub 2} emissions (up to 90 SEK/MWh electricity). If bioenergy in cases with additional costs is to replace electricity from coal condensing plants it is necessary to place a price on the CO{sub 2} emissions by coal power stations and/or submit them to carbon dioxide taxation. This is not the case today. Pellet boilers in multi-family houses can utilise considerable amounts of forest biofuel and provide heating at lower costs than electric boilers. District heating and cogeneration of power and district heating can also utilise large volumes of forest biofuel (up to 20 TWh resulting in more than 12 Mtonnes/year reduced CO{sub 2} emissions) at low added costs (about 60 SEK/tonne reduced CO{sub 2} emissions corresponding to 20-40 SEK/MWh district heating) in comparison with fossil alternatives. Emissions of other air pollutants can then more easily be minimised and will occur further from built-up areas. The amount of electricity that can be produced from forest biofuel at these low added costs in comparison with fossil alternatives is restricted by the level of district-heating production. Today the power transmission systems permit only limited exports of electrical power, and consequently important reductions in CO{sub 2} emissions can be achieved at low cost if electricity from biofuel-fired cogeneration plants, that cannot be exported, is used by new heat pumps in villas. This would also give lower emissions of other air pollutants in urban areas than if pellets or oil were used to fire the villa boilers. Heat pumps and pellet boilers will be the most favourable forest biofuel based heating alternative for villas heated by water radiators. Heat pumps give greater reductions in CO{sub 2

  15. Establishing the Ecological Status of Mining-Impacted Freshwaters from Abrud River Catchment Area Using Benthic Diatom Communities (Ros, ia MontanÄă, Romania)

    Science.gov (United States)

    Olenici, Adriana; Baciu, Calin; Momeu, Laura; Cozma, Alexandra; Brahaita, Dorian; Pop, Cristian; Lazar, Laura; Popita, Gabriela; Teodosiu, Gabriela

    2015-04-01

    Keywords: diatom communities, indicator species, mine waters, water quality, Romania. Diatoms are a very distinct group of algae, identifiable under the light microscope by their yellow - brown coloration and by the presence of a thick silica cell wall. The potential for freshwater organisms to reflect changes in environmental conditions was first noted by Kolenati (1848) and Cohn (1853), who observed that biota in polluted waters were different from those in non-polluted situations. Diatoms are widely used to monitor river pollution because they are sensitive to water chemistry, especially to ionic content, pH, dissolved organic matter and nutrients. Wide geographic distribution and well-studied ecology of most diatom species are mentioned as major advantages of using diatoms as indicator organisms. At the same time water quality has begun to deteriorate increasingly, mainly as a result of the physical, chemical and bacteriological alterations, and the aquatic ecosystems are evermore affected by various types of pollution, the anthropic one being almost always included. A good example is Abrud River and its main tributaries (Roșia Montană and surrounding areas, Romania), which has suffered along the years because of the mining waters discharge. In this context, this study presents data on benthic diatom communities from the Abrud River catchment area. Sixteen sites have been sampled seasonal and the best represented diatom genera were Navicula, Nitzschia, Cymbella, Gomphonema, Achnantes, Surirella and Fragilaria. Qualitatively, the number of diatom species exhibited significant variation among sampling sites, also suggesting seasonal dynamics. For instance, in some sampling sites, algal assemblages were absent, as diatom communities were strongly affected by acid mine waters, released from old mining works and waste rocks depots. Some dominant taxa have been observed as well, suggesting critical saprobic levels of the Abrud River and some of its tributaries. The

  16. 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

  17. Runoff generation mechanism at two distinct headwater catchments - isotopic evidence

    Science.gov (United States)

    Dohnal, Michal; Votrubová, Jana; Šanda, Martin; Tesař, Miroslav; Vogel, Tomáš; Dušek, Jaromír

    2016-04-01

    Data from two headwater catchments indicate considerably different runoff formation mechanisms. The contributions of different surface and subsurface runoff mechanisms to the catchment discharge formation at these two small forested headwater catchments are studied with help of the natural isotopic signatures of the observed fluxes. The Uhlirska catchment (1.78 sq. km, Jizera Mts., Czech Republic) is situated in headwater area of Cerna Nisa stream. Deluviofluvial granitic sediments in the valley bottom areas (riparian zones/wetlands) are surrounded by gentle hillslopes with shallow soils developed on crystalline bedrock. The Liz catchment (0.99 sq. km, Bohemian Forest, Czech Republic) belongs to hillslope-type catchments without riparian zones situated in headwater area of Volynka River. The soil at Liz is developed on biotite paragneiss bedrock. Autocorrelation analysis of the measured catchment discharge rates reveals different hydrograph characteristics for each of the two catchments. Estimated autocorrelation lengths differ by an order of magnitude. Variations of oxygen-18 isotope concentrations in precipitation, groundwater and streamflow were analyzed. Several significant rainfall-runoff events at each of the two catchments were analyzed in detail. These events exhibit substantial difference in isotopic compositions of event and pre-event water, which facilitates hydrograph separation. Clockwise and counterclockwise hysteretic relationships between the stream discharge and its isotope concentration were identified. Results were confronted with the previously published concepts of the runoff formation at the catchments under study. The research was funded by the Czech Science Foundation, project No. 14-15201J.

  18. Before and after integrated catchment management in a headwater catchment: changes in water quality.

    Science.gov (United States)

    Hughes, Andrew O; Quinn, John M

    2014-12-01

    Few studies have comprehensively measured the effect on water quality of catchment rehabilitation measures in comparison with baseline conditions. Here we have analyzed water clarity and nutrient concentrations and loads for a 13-year period in a headwater catchment within the western Waikato region, New Zealand. For the first 6 years, the entire catchment was used for hill-country cattle and sheep grazing. An integrated catchment management plan was implemented whereby cattle were excluded from riparian areas, the most degraded land was planted in Pinus radiata, channel banks were planted with poplar trees and the beef cattle enterprise was modified. The removal of cattle from riparian areas without additional riparian planting had a positive and rapid effect on stream water clarity. In contrast, the water clarity decreased in those sub-catchments where livestock was excluded but riparian areas were planted with trees and shrubs. We attribute the decrease in water clarity to a reduction in groundcover vegetation that armors stream banks against preparatory erosion processes. Increases in concentrations of forms of P and N were recorded. These increases were attributed to: (i) the reduction of instream nutrient uptake by macrophytes and periphyton due to increased riparian shading; (ii) uncontrolled growth of a nitrogen fixing weed (gorse) in some parts of the catchment, and (iii) the reduction in the nutrient attenuation capacity of seepage wetlands due to the decrease in their areal coverage in response to afforestation. Our findings highlight the complex nature of the water quality response to catchment rehabilitation measures.

  19. Before and After Integrated Catchment Management in a Headwater Catchment: Changes in Water Quality

    Science.gov (United States)

    Hughes, Andrew O.; Quinn, John M.

    2014-12-01

    Few studies have comprehensively measured the effect on water quality of catchment rehabilitation measures in comparison with baseline conditions. Here we have analyzed water clarity and nutrient concentrations and loads for a 13-year period in a headwater catchment within the western Waikato region, New Zealand. For the first 6 years, the entire catchment was used for hill-country cattle and sheep grazing. An integrated catchment management plan was implemented whereby cattle were excluded from riparian areas, the most degraded land was planted in Pinus radiata, channel banks were planted with poplar trees and the beef cattle enterprise was modified. The removal of cattle from riparian areas without additional riparian planting had a positive and rapid effect on stream water clarity. In contrast, the water clarity decreased in those sub-catchments where livestock was excluded but riparian areas were planted with trees and shrubs. We attribute the decrease in water clarity to a reduction in groundcover vegetation that armors stream banks against preparatory erosion processes. Increases in concentrations of forms of P and N were recorded. These increases were attributed to: (i) the reduction of instream nutrient uptake by macrophytes and periphyton due to increased riparian shading; (ii) uncontrolled growth of a nitrogen fixing weed (gorse) in some parts of the catchment, and (iii) the reduction in the nutrient attenuation capacity of seepage wetlands due to the decrease in their areal coverage in response to afforestation. Our findings highlight the complex nature of the water quality response to catchment rehabilitation measures.

  20. Can spatial statistical river temperature models be transferred between catchments?

    Science.gov (United States)

    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

  1. An approach to predict water quality in data-sparse catchments using hydrological catchment similarity

    Science.gov (United States)

    Pohle, Ina; Glendell, Miriam; Stutter, Marc I.; Helliwell, Rachel C.

    2017-04-01

    An understanding of catchment response to climate and land use change at a regional scale is necessary for the assessment of mitigation and adaptation options addressing diffuse nutrient pollution. It is well documented that the physicochemical properties of a river ecosystem respond to change in a non-linear fashion. This is particularly important when threshold water concentrations, relevant to national and EU legislation, are exceeded. Large scale (regional) model assessments required for regulatory purposes must represent the key processes and mechanisms that are more readily understood in catchments with water quantity and water quality data monitored at high spatial and temporal resolution. While daily discharge data are available for most catchments in Scotland, nitrate and phosphorus are mostly available on a monthly basis only, as typified by regulatory monitoring. However, high resolution (hourly to daily) water quantity and water quality data exist for a limited number of research catchments. To successfully implement adaptation measures across Scotland, an upscaling from data-rich to data-sparse catchments is required. In addition, the widespread availability of spatial datasets affecting hydrological and biogeochemical responses (e.g. soils, topography/geomorphology, land use, vegetation etc.) provide an opportunity to transfer predictions between data-rich and data-sparse areas by linking processes and responses to catchment attributes. Here, we develop a framework of catchment typologies as a prerequisite for transferring information from data-rich to data-sparse catchments by focusing on how hydrological catchment similarity can be used as an indicator of grouped behaviours in water quality response. As indicators of hydrological catchment similarity we use flow indices derived from observed discharge data across Scotland as well as hydrological model parameters. For the latter, we calibrated the lumped rainfall-runoff model TUWModel using multiple

  2. Stable isotope hydrology in fractured and detritic aquifers at both sides of the South Atlantic Ocean: Mar del Plata (Argentina) and the Rawsonville and Sandspruit river catchment areas (South Africa)

    Science.gov (United States)

    Glok Galli, Melisa; Damons, Matthew E.; Siwawa, Sitembiso; Bocanegra, Emilia M.; Nel, Jacobus M.; Mazvimavi, Dominic; Martínez, Daniel E.

    2017-01-01

    The aim of this work is to characterize the isotope composition of water (2H and 18O) in order to establish the relationship between fractured and detritic aquifers in similar hydrological environments located at both sides of the Atlantic Ocean. The Mar del Plata zone, placed in the Argentine Buenos Aires province in South America, and the Rawsonville and Sandspruit river catchment areas, situated in the Western Cape province in South Africa were compared. Rainwater and groundwater samples from fractured and detritic aquifers were analyzed through laser spectroscopy. In both Argentina and South African study sites, stable isotopes data demonstrate an aquifers recharge source from rainfall. For the Mar del Plata region, two different groups of detritic aquifer's samples with distinct recharge processes can be identified due to the close relationship existing between the present hydrogeological environments, the aquifer's grain size sediments and the isotopes contents: one representing rapid infiltration in aquifer sediments of the creeks' palaeobeds and hills zones (sandy or silt sandy sediments) and the other with slow infiltration of evaporated water in plain zones with an aquitard behavior. In the last group, the evaporation process occurs previous infiltration or in the aquifer's non-saturated zone, because of the existence of very low topographic gradients and fine-grained sediments. The evaporation phenomenon is not evident in the Sandspruit river catchment site's detritic aquifer, because its sandy composition allows a faster infiltration rate than in the loess that compounds the Pampeano aquifer in the interfluves zones of the Argentinian study area.

  3. 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

    model runs per catchment representation explained the different hydrologic responses of the two sub-catchments, which seems to be mainly caused by the presence of dambos in Koga sub-catchment. It is concluded that daily model transferability is not feasible, while it can produce acceptable results for the 15 and 30 days models. This is very useful for water resources planning and management, but not sufficient to capture detailed hydrological processes in an ungauged area.

  4. Alien freshwater polychaetes Hypania invalida (Grube 1860 and Laonome calida Capa 2007 in the Upper Odra River (Baltic Sea catchment area

    Directory of Open Access Journals (Sweden)

    Pabis Krzysztof

    2017-01-01

    Full Text Available Two polychaete species, Hypania invalida and Laonome calida, were found in the Upper Odra River in 2016. Both species were recorded close to a natural river bank down to 1 m depths. They inhabited sandy-gravelly and sandy-muddy sediments. H. invalida is an alien invasive Ponto-Caspian species, previously known in Poland from the Odra River estuary only. Our results may indicate a further rapid dispersal of H. invalida upstream the Odra River or an accidental introduction. This study is the first record of L. calida in the Baltic Sea catchment. This Australian species has been recently introduced into Europe. Prior to this study, it had been reported from Dutch rivers only. The present data suggest accidental introduction of the species to European rivers; however, our findings show an urgent need for a close monitoring of the polychaete in Europe.

  5. 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.

  6. 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

  7. Exceptional hydrological phenomena in the Gemenea catchment

    Directory of Open Access Journals (Sweden)

    Florentina LIVARCIUC

    2015-10-01

    Full Text Available Flash floods, accompanied by high waters and regular floods, represent the most dangerous natural hazards in the Gemenea catchment, inducing other risks such as geomorphologic, environmental, social and economical risks. Flash floods occurred during the 1969 to 2014 monitoring interval are characterized by extremely high discharge values, of 68.9 m3/s in 2006 and 95.3 m3/s in 2008 and a magnitude 2.5 times higher than the average discharge recorded until that timeframe. With an area of 77.7 km2, the Gemenea catchment falls into the category of small catchments, where the peak discharge during exceptional hydrological phenomena is caused by torrential rainfall. Flash floods of particularly high intensities caused serious damages through: total destruction or damage of the torrent correction works, clogging of culverts on catchment forest roads, failure of river banks and deterioration of the bridges that affected roads and homes in Gemenea, Slătioara and Stulpicani villages. These floods have also caused damage to the forest/agriculture fund through deep and lateral erosion, failure of river banks and landslides. Within this study we aim to emphasize the magnitude, frequency, duration and area of manifestation of such phenomena in the Gemenea catchment. Furthermore, we aim to advance our knowledge of the genesis and specific mechanisms of flash flood occurrence for reducing their negative impacts on the local environment and communities

  8. 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

    Storm events mobilize large proportions of sediments in catchment systems. Therefore understanding catchment sediment dynamics throughout the continuity of storms and how initial catchment states act as controls on the transport of sediment to catchment outlets is important for effective catchment management. Sediment connectivity is a concept which can explain the origin, pathways and sinks of sediments within catchments (Baartman et al., 2013; Parsons et al., 2015; Masselink et al., 2016a,b; Mekonnen et al., 2016). However, sediment connectivity alone does not provide a practicable mechanism by which the catchment's initial state - and thus the location of entrained sediment in the sediment transport cascade - can be characterized. Studying the dynamic relationship between water discharge (Q) and suspended sediment (SS) at the catchment outlet can provide a valuable research tool to infer the likely source areas and flow pathways contributing to sediment transport because the relationship can be characterized by predictable hysteresis patterns. Hysteresis is observed when the sediment concentration associated with a certain flow rate is different depending on the direction in which the analysis is performed - towards the increase or towards the diminution of the flow. However, the complexity of the phenomena and factors which determine the hysteresis make its interpretation ambiguous. Previous work has described various types of hysteretic loops as well as the cause for the shape of the loop, mainly pointing to the origin of the sediments. The data set for this study comes from four experimental watersheds in Navarre (Spain), owned and maintained by the Government of Navarre. These experimental watersheds have been monitored and studied since 1996 (La Tejería and Latxaga) and 2001 (Oskotz principal and Oskotz woodland). La Tejería and Latxaga watersheds are similar to each other regarding size (approximately 200 ha), geology (marls and sandstones), soils (fine

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

    Science.gov (United States)

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

    2014-01-01

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

  10. Coverage of Adequately Iodized Salt Is Suboptimal and Rice Fortification Using Public Distribution Channels Could Reach Low-Income Households: Findings from a Cross-Sectional Survey of Anganwadi Center Catchment Areas in Telangana, India.

    Science.gov (United States)

    Wirth, James P; Leyvraz, Magali; Sodani, Prahlad R; Aaron, Grant J; Sharma, Narottam D; Woodruff, Bradley A

    2016-01-01

    Food fortification is a cost-effective approach to prevent and control of micronutrient deficiencies in India. A cross-sectional survey of children 0-35 months of age residing in the catchment areas of anganwadi centers in the state of Telangana was conducted to assess the coverage of adequately iodized salt and the potential for rice fortification. Salt samples were collected and tested for iodine concentration using iodometric titration. Information on demographics, household rice consumption, and Telangana's rice sector was collected and interpreted. In households of selected children, 79% of salt samples were found to be adequately iodized. Salt brand and district were significant predictors of inadequately iodized salt. Daily rice consumption among children and women averaged 122 grams and 321 grams per day, respectively. Approximately 28% of households reported consuming rice produced themselves or purchased from a local farmer, 65% purchased rice from a market or shop, 6% got rice from a public distribution system site, and 2% obtained it from a rice mill. In the catchment areas of Telangana's anganwadi centers, there is significant variation in the coverage of adequately iodized salt by district. Future surveys in Telangana should measure the coverage of salt iodization in the general population using quantitative methods. Nonetheless, increasing the adequacy of iodization of smaller salt manufacturers would help achieve universal salt iodization in Telangana. Despite high consumption of rice, our findings suggest that large-scale market-based rice fortification is not feasible in Telangana due to a large proportion of households producing their own rice and highly fragmented rice distribution. Distributing fortified rice via Telangana's public distribution system may be a viable approach to target low-income households, but would only reach a small proportion of the population in Telangana.

  11. Coverage of Adequately Iodized Salt Is Suboptimal and Rice Fortification Using Public Distribution Channels Could Reach Low-Income Households: Findings from a Cross-Sectional Survey of Anganwadi Center Catchment Areas in Telangana, India.

    Directory of Open Access Journals (Sweden)

    James P Wirth

    Full Text Available Food fortification is a cost-effective approach to prevent and control of micronutrient deficiencies in India. A cross-sectional survey of children 0-35 months of age residing in the catchment areas of anganwadi centers in the state of Telangana was conducted to assess the coverage of adequately iodized salt and the potential for rice fortification. Salt samples were collected and tested for iodine concentration using iodometric titration. Information on demographics, household rice consumption, and Telangana's rice sector was collected and interpreted. In households of selected children, 79% of salt samples were found to be adequately iodized. Salt brand and district were significant predictors of inadequately iodized salt. Daily rice consumption among children and women averaged 122 grams and 321 grams per day, respectively. Approximately 28% of households reported consuming rice produced themselves or purchased from a local farmer, 65% purchased rice from a market or shop, 6% got rice from a public distribution system site, and 2% obtained it from a rice mill. In the catchment areas of Telangana's anganwadi centers, there is significant variation in the coverage of adequately iodized salt by district. Future surveys in Telangana should measure the coverage of salt iodization in the general population using quantitative methods. Nonetheless, increasing the adequacy of iodization of smaller salt manufacturers would help achieve universal salt iodization in Telangana. Despite high consumption of rice, our findings suggest that large-scale market-based rice fortification is not feasible in Telangana due to a large proportion of households producing their own rice and highly fragmented rice distribution. Distributing fortified rice via Telangana's public distribution system may be a viable approach to target low-income households, but would only reach a small proportion of the population in Telangana.

  12. Urbanisation, coastal development and vulnerability, and catchments

    CSIR Research Space (South Africa)

    Ntombela, Cebile

    2015-01-01

    Full Text Available The growth of urban areas that form coastal cities, especially in the WIO, places an increasing demand on natural coastal extractive and non-extractive resources. The use and conversion of coastal land and catchments is considered a permanent effect...

  13. Temporal variability of surface runoff due to cropping systems in cultivated catchment areas: Use of the DIAR model for the assessment of environmental public policies in the Pays de Caux (France).

    Science.gov (United States)

    Martin, P; Joannon, A; Piskiewicz, N

    2010-01-01

    This article proposes the use of a new model, DIAR (Diagnostic Agronomique du Ruissellement, or Agronomic Assessment of Runoff), for the prediction of the timing of the risk of runoff. DIAR is dedicated to loamy soils which are very sensitive to surface crusting, leading to runoff, soil erosion and muddy flows. The approach is proposed for the north-western European loess belt regions where muddy flows severely impact human activities. The likelihood of runoff is assessed from the sequence of soil surface states generated by cultivation practices. DIAR is based on the calculation of curve number values, for each stage of the soil-surface-state sequence, for calculating runoff for each of these stages. In this study, DIAR is applied to a catchment of 912 ha, cultivated by 26 farmers in the Pays de Caux (Normandy, France) where infrastructures located at the outlet have been damaged several times by muddy flows. Local public authorities involved in reducing muddy flows are eager to limit the agricultural upstream runoff by extending the planting of mustard as a winter cover crop. We tested the efficiency of such a policy on the reduction of the mean runoff. We also tested the year-to-year variability of this efficiency using the acreages of four successive years (1999-2000 to 2002-2003). Finally, the cost-efficiency of the policy was also considered. Though we used the same weather scenario, the initial situation (without much mustard cover) showed a wide year-to-year variation in the total runoff. This variation can be associated with the structure of the farms that cultivate the catchment (Utilised Agricultural Area (UAA) of each farm and percentage of this UAA inside the catchment). Our results showed that the widespread planting of winter cover crops could reduce the runoff by 10-20% compared with the initial situation (depending on the year), and also reduce the year-to-year variability of runoff. For each of the 4 tested years, the cost of the infiltrated m(3

  14. Effects of model structure and catchment discretization on discharge simulation in a small forest catchment

    Science.gov (United States)

    Spieler, Diana; Schwarze, Robert; Schütze, Niels

    2017-04-01

    In the past a variety of different modeling approaches has been developed in catchment hydrology. Even though there is no argument on the relevant processes taking place, there is no unified theory on how best to represent them computationally. Thus a vast number of models has been developed, varying from lumped models to physically based models. Most of them have a more or less fixed model structure and follow the "one fits all" paradigm. However, a more flexible approach could improve model realism by designing catchment specific model structures based on data availability. This study focuses on applying the flexible hydrological modelling framework RAVEN (Craig et al., 2013), to systematically test several conceptual model structures on the 19 km2 Große Ohe Catchment in the Bavarian Forest (Germany). By combining RAVEN with the DREAM algorithm (Vrugt et al., 2009), the relationship between catchment characteristics, model structure, parameter uncertainty and data availability are analyzed. The model structure is progressively developed based on the available data of the well observed forested catchment area. In a second step, the impact of the catchment discretization is analyzed by testing different spatial resolutions of topographic input data.

  15. Seasonal and spatial variability of {sup 210}Po, {sup 238}U and {sup 239+240}Pu levels in the river catchment area assessed by application of neural-network based classification

    Energy Technology Data Exchange (ETDEWEB)

    Skwarzec, Bogdan [University of Gdansk, Faculty of Chemistry, Chair of Analytical Chemistry, 18/19 Sobieskiego Street, 80-952 Gdansk (Poland)], E-mail: bosk@chem.univ.gda.pl; Kabat, Krzysztof [University of Gdansk, Faculty of Chemistry, Chair of Analytical Chemistry, 18/19 Sobieskiego Street, 80-952 Gdansk (Poland); Astel, Aleksander [Pomeranian Academy, Biology and Environmental Protection Institute, Environmental Chemistry Research Unit, 22a Arciszewskiego Street, 76-200 Slupsk (Poland)

    2009-02-15

    The present study deals with the application of self-organizing maps (SOM) in order to model, classify and interpret seasonal and spatial variability of {sup 210}Po, {sup 238}U and {sup 239+240}Pu levels in the Vistula river basin. The data set represents concentration values for 3 alpha emitters ({sup 210}Po, {sup 238}U and {sup 239+240}Pu) measured in surface water samples collected at 19 different sampling locations (8 in major Vistula stream while 11 in right or left Vistula tributaries) during four seasons (winter, spring, summer and autumn) in the framework of a one-year quality monitoring study. The advantages of an SOM algorithm, its classification and visualization ability for environmental data sets, are stressed. The neural-network based classification made it possible to reveal specific patterns related to both seasonal and spatial variability. In the middle and upper part of Vistula catchment as well as in the right-shore tributaries, concentrations of {sup 210}Po and {sup 238}U during summer and winter are the lowest. Concentrations of {sup 210}Po and {sup 238}U increase significantly during spring and autumn in the Vistula river catchment, especially in the delta of Vistula river. High concentration of anthropogenic originated {sup 239+240}Pu indicates 'site-specific' character of pollution in two large left-shore tributaries located in the middle part of the Vistula drainage area. Efficient classification of sampling locations could lead to an optimization of river radiochemical sampling networks and to a better tracing of natural and anthropogenic changes along Vistula river stream.

  16. Bayes-Markov analysis for rain-catchment cisterns

    National Research Council Canada - National Science Library

    Fok, Y.S; Fong, R.H.L; Hung, J; Murabayashi, E.T; Lo, A

    1980-01-01

    ... and plnners as a 'new' and important alternative water supply. Rainfall, catchment area, storage capacity of the cistern, and water demand are the four main elements considered in the design, operation and management of a cistern system...

  17. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Bedrock Geology

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tabular data set represents the area of bedrock geology types in square meters compiled for every catchment of MRB_E2RF1 catchments for Major River Basins...

  18. A Treatment Train Approach To Catchment Management

    Science.gov (United States)

    Barber, Nick; Quinn, Paul; Org, EdenDTC

    2017-04-01

    The treatment train approach has been attempted in a 1.6km2 catchment in the River Eden as part of the UK Demonstration Test Catchment Project. The catchment is one of three detailed study catchments of 10km2 that are investigating diffuse pollution losses from an intense grassland farming system. The catchment is very susceptible to saturation and high losses of fine sediment and phosphorus in storm events. The poster will show how a sequence of mitigation features that target nutrient sources and flow pathways can reduce nutrient losses. 5 features have been installed from farmyard runoff control, along polluting tracks and sediment traps in the farm ditch network. Together the features can slow, store and trap sediment and pollutants. The potential to have further impacts on flood generation and drought mitigation are also being studied. Although the features are currently small in size the ability to directly reduce pollution can be demonstrated. Hence, the potential to scale up these features to a broader catchment scale can be explored and the likely costs and benefits can be simulated. This work builds upon similar work addressing flood control features, sediment trapping on farms and methods for the direct mitigation of fast polluting pathways often referred to as Nature Based Solutions. The designs and construction of the completed features will be shown in the poster. Early results show that the combined effect of the 5 features can significantly impact on sediment and pollution during storm events. The specific yield of the impact was 42 kg of suspended sediment/ha 0.06 kg P/ha of P trapped and 0.16 kg of N/ha. This mitigation impact is derived from an area of only 0.02% of the catchment. The potential to increase the mitigated area is thus large. Payment schemes for farmers could encourage the take up the of these methods and future maintenance regimes for managing the features would also have to be created. However, the potential to mitigate fast

  19. Using biophysical models to manage nitrogen pollution from agricultural sources: Utopic or realistic approach for non-scientist users? Case study of a drinking water catchment area in Lorraine, France.

    Science.gov (United States)

    Bernard, Pierre-Yves; Benoît, Marc; Roger-Estrade, Jean; Plantureux, Sylvain

    2016-12-01

    The objectives of this comparison of two biophysical models of nitrogen losses were to evaluate first whether results were similar and second whether both were equally practical for use by non-scientist users. Results were obtained with the crop model STICS and the environmental model AGRIFLUX based on nitrogen loss simulations across a small groundwater catchment area (<1 km(2)) located in the Lorraine region in France. Both models simulate the influences of leaching and cropping systems on nitrogen losses in a relevant manner. The authors conclude that limiting the simulations to areas where soils with a greater risk of leaching cover a significant spatial extent would likely yield acceptable results because those soils have more predictable leaching of nitrogen. In addition, the choice of an environmental model such as AGRIFLUX which requires fewer parameters and input variables seems more user-friendly for agro-environmental assessment. The authors then discuss additional challenges for non-scientists such as lack of parameter optimization, which is essential to accurately assessing nitrogen fluxes and indirectly not to limit the diversity of uses of simulated results. Despite current restrictions, with some improvement, biophysical models could become useful environmental assessment tools for non-scientists.

  20. Factors controlling sediment and phosphorus export from two Belgian agricultural catchments.

    Science.gov (United States)

    Steegen, A; Govers, G; Takken, I; Nachtergaele, J; Poesen, J; Merckx, R

    2001-01-01

    Sediment and total phosphorus (TP) export vary through space and time. This study was conducted to determine the factors controlling sediment and TP export in two agricultural catchments situated in the Belgian Loess Belt. At the outlet of these catchments runoff discharge was continuously measured and suspended sediment samples were taken during rainfall events. Within the catchments vegetation type and cover, soil surface parameters, erosion features, sediment pathways, and rainfall characteristics were monitored. Total P content and sediment characteristics such as clay, organic carbon, and suspended sediment concentration were correlated. Total sediment and TP export differ significantly between the monitored catchments. Much of the difference is due to the occurrence of an extreme event in one catchment and the morphology and spatial organization of land use in the catchments. In one catchment, the direct connection between erosive areas and the catchment outlet by means of a road system contributed to a high sediment delivery ratio (SDR) at the outlet. In the other catchment, the presence of a wide valley in the center of the catchment caused sediment deposition. Vegetation also had an effect on sediment production and deposition. Thus, many factors control sediment and TP export from small agricultural catchments; some of these factors are related to the physical catchment characteristics such as morphology and landscape structure and are (semi)permanent, while others, such as vegetation cover and land use, are time dependent.

  1. 步行距离、港铁出行意愿与站域范围的关联研究%Research on Relationship of Catchment Area, MTR Riding Intent and Walking Distance in Hong Kong

    Institute of Scientific and Technical Information of China (English)

    殷子渊

    2016-01-01

    如何确定轨道站影响范围(站域)是研究轨道与城市空间问题的基础,该问题涉及居民步行距离与轨道乘坐意愿的关系。距离是影响人们步行出行的重要因素,影响公共基础设施的服务范围。目前针对步行距离因素如何影响居民轨道通勤出行意愿的定量研究尚少,这种局面对于定量理解轨道站的影响范围(站域)非常不利。基于725栋香港居住建筑轨道通勤出行意愿调查结果的研究,运用了指数距离衰减模型对香港居民步行距离和轨道乘坐意愿进行关联分析,通过比对不同距离区间衰减系数‘β’的变化趋势,分析了真实步行距离如何影响港铁通勤出行的意愿和距离阈值空间。步行距离阈值范围的研究为分级确定轨道站影响区域提供了定量的依据;使用绕路系数指标可以评价站域空间结构,并为轨道站周边空间的建设与整合提供量化依据。%Catchment area is one of crucial issues in research of transit system and urban space. Based on survey of MTR commuting travel rate in Hong Kong, this research employed exponent distance decay model to analyze on how distance impact on metro riding intent. Based on surveys of MTR commuting rate from 725 residential buildings, the ranges of thresholds can be concluded where distance impacting on riding intent intensively through comparative study of the measuring of decay coefficient, whereby the catchment area of metro station can be defined quantitatively by factors as detour rate and walking distance.

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

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available 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.

  3. The identification of suitable areas for afforestation in order to reduce the potential for surface runoff in the upper and middle sectors of Buzãu catchment

    Directory of Open Access Journals (Sweden)

    ROMULUS COSTACHE

    2015-07-01

    Full Text Available Deforestations, besides the global climate change, are the main cause of the intensification of f loods and flash - floods in the latest years. Since surface runoff is the main phenomenon leading to floods or flash - floods, afforestation is necessary, forest coverage being the element that retains most of the water from precipitation. The study area, repr esented by the upper and middle sectors of Buzau River basin, is one of the most affected regions of Romania by torrential phenomena. Also, the study area was chosen due to its considerable deforestation. This paper proposes a methodology created exclusive ly by GIS techniques in order to identify the areas suitable for afforestation. Thus, land cover and slope relief were taken into account when running the GIS model. Database processing and obtaining the final results were possible by implementing a workfl ow in Model Builder from ArcGIS 10.3, which can be later used as a tool for other study areas. The results of the study highlight Balaneasa, Bâsca Chiojdului and Sărăţel river basins, which record the highest shares of areas suitable for afforestation.

  4. UnLoadC3: Ensembles of climate change projections for two river catchment areas in Austria - Contributions to an overall uncertainty assessment framework for the modelling of water quantity and nutrient transport

    Science.gov (United States)

    Matulla, Christoph; Hollosi, Brigitta; Schulz, Karsten; Schürz, Christoph; Mehdi, Bano; Ertl, Thomas; Pressl, Alexander

    2017-04-01

    The objective of UnLoadC3 is to examine the impacts of uncertainty - inherent in data and modelling - on projections of water flow and nutrient transport within two selected river catchment areas (Schwechat and Raab in Austria) under climate change conditions. To access future climate change, ensembles of climate projections from the EURO-CORDEX initiative - given on grids with a 12 km spacing - have been used. These ensembles have been driven by two RCPs (RCP4.5 and RCP8.5) used within the Fifth Assessment Report of the IPCC. In order to provide climate change projections on the required impact scales, statistical downscaling techniques as well as bias correction methods have been applied. Climate variables, such as minimum, maximum, mean temperature and precipitation totals given on a daily base were analyzed. This local scale daily information is entered into the water quality model SWAT, which simulates water balance, pertaining sediment- and nutrient-transport processes across the two considered river watersheds.

  5. The research of the contamination levels present in samples of precipitation and surface waters collected from the catchment area Fuglebekken (Hornsund, Svalbard Archipelago)

    Science.gov (United States)

    Ruman, Marek; Szopińska, Małgorzata; Kozak, Katarzyna; Lehmann, Sara; Polkowska, Żaneta

    2014-10-01

    Persistent organic pollutants (POPs) are contaminants that may appear in polar regions. In present work surface water was collected from the main stream water in the Fuglebekken basin. The precipitationsamples was collected from the near area by Polish Polar Station in Hornsund. The present investigationreveals the results of the analysis of these samples for their total phenols, formaldehyde, TOC, PAHs and PCBs content. The presence in the basin (thousands of kilometers distant from industrial centers) of those compounds is testimony to the fact that these compounds are transported over vast distances with air masses and deposited in regions devoid of any human impact.

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

    Directory of Open Access Journals (Sweden)

    Ioan Bâca

    2015-07-01

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

  7. Chemical weathering and runoff chemistry in a steep headwater catchment

    Science.gov (United States)

    Anderson, Suzanne Prestrud; Dietrich, William E.

    2001-07-01

    We present here deductions about the location, rate, and mechanisms of chemical weathering in a small catchment based on a catchment-scale sprinkling experiment. In this experiment demineralized water was applied at an approximately steady rate in the CB1 catchment in the Oregon Coast Range to reach and maintain a quasi-steady discharge for a period of 4 days. Because of nearly steady flow conditions within the catchment, the contribution to solute fluxes from soil and bedrock could be partitioned. One half of the solute flux from the catchment derived from colluvial soil, and one half from weathering in bedrock. This implies more intense weathering in the thin colluvium mantling the catchment than in the thick underlying weathered bedrock. The annual solute flux from the catchment, scaled to the annual runoff from the catchment, is 32 +/- 10 t km-2 year-1, equivalent to published chemical denudation rates for nearby rivers with drainage areas 106 times greater than the experiment site. Soil waters sampled during the sprinkling experiment had steady compositions following a period of transient water flow conditions, implying steady-state chemical evolution in the soil. The waters leached organic anions from shallow depths in the soil, which solubilized aluminium and iron, indicating that podzolization is occurring in these soils. Carbonate dissolution appears to be an important source of solutes from the bedrock, despite being present as only a minor phase in the rock. Water balance suggests that the residence time of water in the catchment is about 2 months, and that typical 24 h storms displace only a fraction of the stored water. A consequence is that runoff chemistry is dominated by old water, which imposes strong limits on the variability of runoff composition.

  8. Hydroclimatic change disparity of Peruvian Pacific drainage catchments

    Science.gov (United States)

    Rau, Pedro; Bourrel, Luc; Labat, David; Frappart, Frédéric; Ruelland, Denis; Lavado, Waldo; Dewitte, Boris; Felipe, Oscar

    2017-09-01

    Peruvian Pacific drainage catchments only benefit from 2% of the total national available freshwater while they concentrate almost 50% of the population of the country. This situation is likely to lead a severe water scarcity and also constitutes an obstacle to economic development. Catchment runoff fluctuations in response to climate variability and/or human activities can be reflected in extreme events, representing a serious concern (like floods, erosion, droughts) in the study area. To document this crucial issue for Peru, we present here an insightful analysis of the water quantity resource variability of this region, exploring the links between this variability and climate and/or anthropogenic pressure. We first present a detailed analysis of the hydroclimatologic variability at annual timescale and at basin scale over the 1970-2008 period. In addition to corroborating the influence of extreme El Niño events over precipitation and runoff in northern catchments, a mean warming of 0.2 °C per decade over all catchments was found. Also, higher values of temperature and potential and actual evapotranspiration were found over northern latitudes. We chose to apply the Budyko-Zhang framework that characterizes the water cycle as a function of climate only, allowing the identification of catchments with significant climatic and anthropogenic influence on water balance. The Budyko-Zhang methodology revealed that 11 out of 26 initial catchments are characterized by low water balance disparity related to minor climatic and anthropogenic influence. These 11 catchments were suitable for identifying catchments with contrasting change in their hydroclimatic behavior using the Budyko trajectories. Our analysis further reveals that six hydrological catchment responses can be characterized by high sensitivity to climate variability and land use changes.

  9. Modelling the Caspian Sea and its catchment area using a coupled regional atmosphere-ocean model (RegCM4-ROMS: model design and preliminary results

    Directory of Open Access Journals (Sweden)

    U. U. Turuncoglu

    2013-03-01

    Full Text Available We describe the development of a coupled regional atmosphere-ocean model (RegCM4-ROMS and its implementation over the Caspian Sea basin. The coupled model is run for the period 1999–2008 (after a spin up of 4 yr and it is compared to corresponding stand alone model simulations and a simulation in which a distributed 1d lake model is run for the Caspian Sea. All model versions show a good performance in reproducing the climatology of the Caspian Sea basin, with relatively minor differences across them. The coupled ROMS produces realistic, although somewhat overestimated, Caspian Sea Surface Temperature (SST, with a considerable improvement compared to the use of the simpler coupled lake model. Simulated near surface salinity and sea currents are also realistic, although the upwelling over the eastern coastal regions is underestimated. The sea ice extent over the shallow northern shelf of the Caspian Sea and its seasonal evolution are well reproduced, however, a significant negative bias in sea-ice fraction exists due to the relatively poor representation of the bathymetry. ROMS also calculates the Caspian Sea Level (CSL, showing that for the present experiment excessive evaporation over the lake area leads to a drift in estimated CSL. Despite this problem, which requires further analysis due to many uncertainties in the estimation of CSL, overall the coupled RegCM4-ROMS system shows encouraging results in reproducing both the climatology of the region and the basic characteristics of the Caspian Sea.

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

    Directory of Open Access Journals (Sweden)

    Ioan Bâca

    2015-08-01

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

  11. Modeling the Caspian Sea and its catchment area using a coupled regional atmosphere-ocean model (RegCM-ROMS: model design and preliminary results

    Directory of Open Access Journals (Sweden)

    U. U. Turuncoglu

    2012-11-01

    Full Text Available We describe the development of a coupled regional atmosphere-ocean model (RegCM-ROMS and its implementation over the Caspian Sea basin. The coupled model is run for the period 1999–2008 (after a spin up of 4 yr and it is compared to corresponding stand alone model simulations and a simulation in which a distributed 1d lake model is run for the Caspian Sea. All model versions show a good performance in reproducing the climatology of the Caspian Sea basin, with relatively minor differences across them. The coupled ROMS produces realistic, although somewhat overestimated, lake surface temperatures (LSTs, with a considerable improvement compared to the use of the simpler coupled lake model. Simulated near surface salinity and sea currents are also realistic, although the upwelling over the eastern coastal regions is underestimated. The distribution of sea ice over the shallow northern shelf of the Caspian Sea and its seasonal evolution are well reproduced. ROMS also calculates the Caspian Sea Level (CSL, showing that for the present experiment excessive evaporation over the lake area leads to a drift in estimated CSL. Despite this problem which requires further analysis due to many uncertainties in the estimation of CSL, overall the coupled RegCM-ROMS system shows encouraging results in reproducing both the climatology of the region and the basic characteristics of the Caspian Sea.

  12. Understanding Hydrological Processes in an Ungauged Catchment in sub-Saharan Africa

    NARCIS (Netherlands)

    Mul, M.L.

    2009-01-01

    Ungauged catchments can be found in many parts of the world, but particularly in sub-Saharan Africa. Information collected in a gauged catchment and its regionalisation to ungauged areas is crucial for water resources assessment. Especially farmers in semi-arid areas are in need of such information.

  13. Development of a process-oriented vulnerability concept for water travel time in karst aquifers-case study of Tanour and Rasoun springs catchment area.

    Science.gov (United States)

    Hamdan, Ibraheem; Sauter, Martin; Ptak, Thomas; Wiegand, Bettina; Margane, Armin; Toll, Mathias

    2017-04-01

    Key words: Karst aquifer, water travel time, vulnerability assessment, Jordan. The understanding of the groundwater pathways and movement through karst aquifers, and the karst aquifer response to precipitation events especially in the arid to semi-arid areas is fundamental to evaluate pollution risks from point and non-point sources. In spite of the great importance of the karst aquifer for drinking purposes, karst aquifers are highly sensitive to contamination events due to the fast connections between the land-surface and the groundwater (through the karst features) which is makes groundwater quality issues within karst systems very complicated. Within this study, different methods and approaches were developed and applied in order to characterise the karst aquifer system of the Tanour and Rasoun springs (NW-Jordan) and the flow dynamics within the aquifer, and to develop a process-oriented method for vulnerability assessment based on the monitoring of different multi-spatially variable parameters of water travel time in karst aquifer. In general, this study aims to achieve two main objectives: 1. Characterization of the karst aquifer system and flow dynamics. 2. Development of a process-oriented method for vulnerability assessment based on spatially variable parameters of travel time. In order to achieve these aims, different approaches and methods were applied starting from the understanding of the geological and hydrogeological characteristics of the karst aquifer and its vulnerability against pollutants, to using different methods, procedures and monitored parameters in order to determine the water travel time within the aquifer and investigate its response to precipitation event and, finally, with the study of the aquifer response to pollution events. The integrated breakthrough signal obtained from the applied methods and procedures including the using of stable isotopes of oxygen and hydrogen, the monitoring of multi qualitative and quantitative parameters

  14. Potential accessibility scores for hospital care in a province of Japan: GIS-based ecological study of the two-step floating catchment area method and the number of neighborhood hospitals.

    Science.gov (United States)

    Nakamura, Takashi; Nakamura, Akihisa; Mukuda, Kengo; Harada, Masanori; Kotani, Kazuhiko

    2017-06-26

    For achieving equity of the accessibility to primary healthcare, measuring potential geographical accessibility is essential. The provider-to-population ratio is the most frequently used measure. However, it is difficult to be used in closer region because it does not take into consideration the people and health services beyond its boundary. In order to overcome this problem, we measured the potential access to hospital, using both distance measures and the enhanced two-step floating catchment area (E2SFCA) method. The aim of this study was to compare the number of hospitals in the neighborhood and the E2SFCA score with regard to the amount and equity for access to hospitals. This descriptive study used publicly available data from 2010. The E2SFCA score and number of neighborhood hospitals were obtained from Tochigi province in Japan using a geographic information system. Dataset of four measures by each census tract was obtained. The measures were E2SFCA score, number of hospitals within the 5 km range, number of hospitals within the 10 km range, and number of hospitals within the 15 km range. Correlation and disparity analyses with the Lorenz curve and Gini coefficient were performed. The measures were obtained in a smaller area than municipality considering adjacent areas using a geographical approach. The E2SFCA score was 5.3 [3.2-7.3] hospitals/million (median [quantile range]), compared to 5.6 hospitals/million in total for the given district. The median number of hospitals within the 5 km, 10 km, and 15 km ranges were 1, 39, and 47, respectively. There was no hospital within the 5 km range in one third of the blocks. Both the number of hospitals within the 10 km range and those within the 15 km range were well correlated. Regional difference became smaller as the distance to count the number of hospitals increased. The gap between small number of hospitals and the high E2SFCA score indicated the location of community hospital in depopulated areas

  15. River water quality modelling in developing a catchment water safety plan

    OpenAIRE

    Vieira, J. M. Pereira; Pinho, José L. S.

    2014-01-01

    The primary aim of a catchment water safety plan is to reduce risks within the catchment to protect the quality of drinking water sources at the intake point. Even where effective arrangements for catchment management and control have been implemented, unexpected deterioration in raw water quality can pose a risk to treated drinking water quality. Thus potential sources of pollution impacting the area of influence of the intake should be identified and monitored. An important part of any catc...

  16. Distribution of polycyclic aromatic hydrocarbons (PAHs) in sewage effluent, continental and coastal waters from the Northwestern Mediterrean Sea: Comparison between two contrasted catchment areas (Marseilles Bay and Vermeille coast)

    Science.gov (United States)

    Guigue, Catherine; Ferretto, Nicolas; Méjanelle, Laurence; Tedetti, Marc; Ghiglione, Jean-François; Goutx, Madeleine

    2014-05-01

    combusted fossil fuels, whatever the season, revealing a very distinct pattern from the Marseilles area. These results show the importance of the dissolved compartment dynamics, especially spatio-temporal variability at catchment scale, when assessing the budget of organic pollutants in coastal environments.

  17. Susceptibility of Shallow Landslide in Fraser Hill Catchment, Pahang Malaysia

    Directory of Open Access Journals (Sweden)

    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

  18. Influence of catchment-scale military land use on stream physical and organic matter variables in small Southeaster Plains Catchments (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, Kelly [Auburn University, Auburn, Alabama

    2005-01-01

    We conducted a 3-year study designed to examine the relationship between disturbance from military land use and stream physical and organic matter variables within 12 small (<5.5 km2) Southeastern Plains catchments at the Fort Benning Military Installation, Georgia, USA. Primary land-use categories were based on percentages of bare ground and road cover and nonforested land (grasslands, sparse vegetation, shrublands, fields) in catchments and natural catchments features, including soils (% sandy soils) and catchment size (area). We quantified stream flashiness (determined by slope of recession limbs of storm hydrographs), streambed instability (measured by relative changes in bed height over time), organic matter storage [coarse wood debris (CWD) relative abundance, benthic particulate organic matter (BPOM)] and stream-water dissolved organic carbon concentration (DOC). Stream flashiness was positively correlated with average storm magnitude and percent of the catchment with sandy soil, whereas streambed instability was related to percent of the catchment containing nonforested (disturbed) land. The proportions of in-stream CWD and sediment BPOM, and stream-water DOC were negatively related to the percent of bare ground and road cover in catchments. Collectively, our results suggest that the amount of catchment disturbance causing denuded vegetation and exposed, mobile soil is (1) a key terrestrial influence on stream geomorphology and hydrology and (2) a greater determinant of in-stream organic matter conditions than is natural geomorphic or topographic variation (catchment size, soil type) in these systems.

  19. Internally Drained Supraglacial River Catchments on the Southwest Greenland Ice Sheet

    Science.gov (United States)

    Yang, K.; Smith, L. C.; Chu, V. W.; Pitcher, L. H.; Gleason, C. J.

    2015-12-01

    Internally drained catchments are the hydrologic units on the Greenland ice sheet (GrIS) surface that collect and drain meltwater into moulins or supraglacial lakes without out flows. Understanding the spatial pattern of these internal catchments is critical, which can provide key information about how supraglacial meltwater is transported and released on the ice surface. This study proposed an automatic approach to detect supraglacial hydrologic features (rivers, lakes, moulins, and internal catchments) located at southwest GrIS from Landsat-8 OLI panchromatic imagery. A total of 800 internal catchments are delineated and the average catchment size (river network length) is found to increase with elevations. In addition, moulins are the prime way to drain internal catchments and the average moulin densities decrease with elevations. Adaptive depression area thresholds are calculated to achieve optimal match between DEM-modeled and image-detected internal catchment patterns. The pattern of these image-detected internal catchments also indicates that: 1) not all the DEM-modeled topographic depressions act as meltwater sinks; 2) moulin distribution greatly impacts the internal catchment patterns; and 3) topographic depressions can be connected downstream without being fully filled, changing the fragmentary of the internal catchments.

  20. Remote sensing of surface water quality in relation to catchment condition in Zimbabwe

    Science.gov (United States)

    Masocha, Mhosisi; Murwira, Amon; Magadza, Christopher H. D.; Hirji, Rafik; Dube, Timothy

    2017-08-01

    The degradation of river catchments is one of the most important contemporary environmental problems affecting water quality in tropical countries. In this study, we used remotely sensed Normalised Difference Vegetation Index (NDVI) to assess how catchment condition varies within and across river catchments in Zimbabwe. We then used non-linear regression to test whether catchment condition assessed using the NDVI is significantly (α = 0.05) related with levels of Total Suspended Solids (TSS) measured at different sampling points in thirty-two sub-catchments in Zimbabwe. The results showed a consistent negative curvilinear relationship between Landsat 8 derived NDVI and TSS measured across the catchments under study. In the drier catchments of the country, 98% of the variation in TSS is explained by NDVI, while in wetter catchments, 64% of the variation in TSS is explained by NDVI. Our results suggest that NDVI derived from free and readily available multispectral Landsat series data (Landsat 8) is a potential valuable tool for the rapid assessment of physical water quality in data poor catchments. Overall, the finding of this study underscores the usefulness of readily available satellite data for near-real time monitoring of the physical water quality at river catchment scale, especially in resource-constrained areas, such as the sub-Saharan Africa.

  1. 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.

  2. Similarity and scale in catchment storm response

    Science.gov (United States)

    Wood, Eric F.; Sivapalan, Murugesu; Beven, Keith

    1993-01-01

    Until recently, very little progress had been made in understanding the relationship between small-scale variability of topography, soil, and rainfalls and the storm response seen at the catchment scale. The work reviewed here represents the first attempt at a systematic theoretical framework for such understanding in the context of surface runoff generation by different processes. The parameterization of hydrological processes over a range of scales is examined, and the concept of the 'representative elementary area' (REA) is introduced. The REA is a fundamental scale for catchment modeling at which continuum assumptions can be applied for the spatially variable controls and parameters, and spatial patterns no longer have to be considered explicitly. The investigation of scale leads into the concept of hydrologic similarity in which the effects of the environmental controls on runoff generation and flood frequency response be investigated independently of catchment scale. The paper reviews the authors' initial results and hopefully will motivate others to also investigate the issues of hydrologic scale and similarity.

  3. Creating a catchment perspective for river restoration

    Science.gov (United States)

    Benda, L.; Miller, D.; Barquín, J.

    2011-03-01

    One of the major challenges in river restoration is to identify the natural fluvial landscape in catchments with a long history of river control. Intensive land use on valley floors often predates the earliest remote sensing: levees, dikes, dams, and other structures alter valley-floor morphology, river channels and flow regimes. Consequently, morphological patterns indicative of the fluvial landscape including multiple channels, extensive floodplains, wetlands, and fluvial-riparian and tributary-confluence dynamics can be obscured, and information to develop appropriate and cost effective river restoration strategies can be unavailable. This is the case in the Pas River catchment in northern Spain (650 km2), in which land use and development have obscured the natural fluvial landscape in many parts of the basin. To address this issue we coupled general principles of hydro-geomorphic processes with computer tools to characterize the fluvial landscape. Using a 5-m digital elevation model, valley-floor surfaces were mapped according to elevation above the channel and proximity to key geomorphic processes. The predicted fluvial landscape is patchily distributed according to topography, valley morphology, river network structure, and fan and terrace landforms. The vast majority of the fluvial landscape in the main segments of the Pas River catchment is presently masked by human infrastructure, with only 15% not impacted by river control structures and development. The reconstructed fluvial landscape provides a catchment scale context to support restoration planning, in which areas of potential ecological productivity and diversity could be targeted for in-channel, floodplain and riparian restoration projects.

  4. Creating a catchment perspective for river restoration

    Directory of Open Access Journals (Sweden)

    L. Benda

    2011-03-01

    Full Text Available One of the major challenges in river restoration is to identify the natural fluvial landscape in catchments with a long history of river control. Intensive land use on valley floors often predates the earliest remote sensing: levees, dikes, dams, and other structures alter valley-floor morphology, river channels and flow regimes. Consequently, morphological patterns indicative of the fluvial landscape including multiple channels, extensive floodplains, wetlands, and fluvial-riparian and tributary-confluence dynamics can be obscured, and information to develop appropriate and cost effective river restoration strategies can be unavailable. This is the case in the Pas River catchment in northern Spain (650 km2, in which land use and development have obscured the natural fluvial landscape in many parts of the basin. To address this issue we coupled general principles of hydro-geomorphic processes with computer tools to characterize the fluvial landscape. Using a 5-m digital elevation model, valley-floor surfaces were mapped according to elevation above the channel and proximity to key geomorphic processes. The predicted fluvial landscape is patchily distributed according to topography, valley morphology, river network structure, and fan and terrace landforms. The vast majority of the fluvial landscape in the main segments of the Pas River catchment is presently masked by human infrastructure, with only 15% not impacted by river control structures and development. The reconstructed fluvial landscape provides a catchment scale context to support restoration planning, in which areas of potential ecological productivity and diversity could be targeted for in-channel, floodplain and riparian restoration projects.

  5. The Effect of Converting Combined Sewer Catchments to Separate Sewer Catchments

    DEFF Research Database (Denmark)

    Schaarup-Jensen, Kjeld; Rasmussen, Michael R.; Thorndahl, Søren Liedtke

    2011-01-01

    The overall objective of this paper is to contribute to the standing debate concerning the advantages of separate sewer systems compared to traditional combined sewers. By a case study this investigation reveals that a transformation of one fourth of a given total area from being combined to become...... separate sewer catchments decreases the amounts of storm water and pollutants diverted to the waste water treatment plant (WWTP) or as combined sewer overflows (CSO). But this happens at the expense of an increase in amounts of storm water and pollutants diverted to local receiving waters when detention...... ponds are not built-in the new separate sewer systems. If a total catchment area transformation – instead of only one fourth – is put through, the consequences could be fatal for receiving waters if no retention of pollutants is integrated in such a transformation....

  6. The Effect of Converting Combined Sewer Catchments to Separate Sewer Catchments

    DEFF Research Database (Denmark)

    Schaarup-Jensen, Kjeld; Rasmussen, Michael R.; Thorndahl, Søren Liedtke

    2011-01-01

    The overall objective of this paper is to contribute to the standing debate concerning the advantages of separate sewer systems compared to traditional combined sewers. By a case study this investigation reveals that a transformation of one fourth of a given total area from being combined to become...... separate sewer catchments decreases the amounts of storm water and pollutants diverted to the waste water treatment plant (WWTP) or as combined sewer overflows (CSO). But this happens at the expense of an increase in amounts of storm water and pollutants diverted to local receiving waters when detention...... ponds are not built-in the new separate sewer systems. If a total catchment area transformation – instead of only one fourth – is put through, the consequences could be fatal for receiving waters if no retention of pollutants is integrated in such a transformation....

  7. Factors controlling inter-catchment variation of mean transit time with consideration of temporal variability

    Science.gov (United States)

    Ma, Wenchao; Yamanaka, Tsutomu

    2016-03-01

    The catchment transit time, a lumped descriptor reflecting both time scale and spatial structure of catchment hydrology can provide useful insights into chemical/nuclear pollution risks within a catchment. Despite its importance, factors controlling spatial variation of mean transit time (MTT) are not yet well understood. In this study, we estimated time-variant MTTs for about ten years (2003-2012) in five mesoscale sub-catchments of the Fuji River catchment, central Japan, to establish the factors controlling their inter-catchment variation with consideration of temporal variability. For this purpose, we employed a lumped hydrological model that was calibrated and validated by hydrometric and isotopic tracer observations. Temporal variation patterns of estimated MTT were similar in all sub-catchments, but with differing amplitudes. Inter-catchment variation of MTT was greater in dry periods than wet periods, suggesting spatial variation of MTT is controlled by water 'stock' rather than by 'flow'. Although the long-term average MTT (LAMTT) in each catchment was correlated with mean slope, coverage of forest (or conversely, other land use types), coverage of sand-shale conglomerate, and groundwater storage, the multiple linear regression revealed that inter-catchment variation of LAMTT is principally controlled by the amount of groundwater storage. This is smaller in mountainous areas covered mostly by forests and greater in plain areas with less forest coverage and smaller slope. This study highlights the topographic control of MTT via groundwater storage, which might be a more important factor in mesoscale catchments, including both mountains and plains, rather than in smaller catchments dominated by mountainous topography.

  8. Sediment transport in steep forested catchments - An assessment of scale and disturbance

    Science.gov (United States)

    Hancock, G. R.; Hugo, J.; Webb, A. A.; Turner, L.

    2017-04-01

    Stream sediment loads (both bedload and suspended sediment) are problematic to measure due to the time and equipment needed. There is a dearth of such data sets globally let alone for Australia. However, such data are needed to quantify sediment transport type and rates, landscape evolution, effect of human disturbance as well as patterns and temporal response. Here we present the findings from 8 steepslope forested catchments dominated by headwater streams (size range 15-100 ha) in south-eastern Australia where both bedload and suspended load have been measured over multiple years. The results demonstrate that suspended load is the dominant component and there is no consistent suspended to bedload ratio for the catchments. The suspended sediment to bedload ratio appears to be catchment specific. There was no relationship between total load (or bedload/suspended load) and average catchment slope, stream length, shape or any geomorphic descriptor. However catchment total load was found to be significantly related to catchment area. Of the 8 catchments examined here, 6 had been harvested for timber in previous decades (with large areas of forest removed) while 2 catchments had minimal disturbance (Control catchments). There was no difference in sediment loads from the harvested and Control catchments. The results demonstrate that although land disturbance had previously occurred the management practices employed in each catchment were effective in the long term. This provides confidence that the forest harvesting and subsequent management do not produce detrimental effects in the medium to long term. An assessment of erosion rates and likely soil production rates suggests that the catchments are eroding soil at the rate it is being produced.

  9. Water displacement by sewer infrastructure in the Grote Nete catchment, Belgium, and its hydrological regime effects

    OpenAIRE

    Vrebos, D.; T. Vansteenkiste; Staes, J.; Willems, P.; Meire, P.

    2013-01-01

    Urbanization and especially impervious areas, in combination with wastewater treatment infrastructure, can exert several pressures on the hydrological cycle. These pressures were studied for the Grote Nete catchment in Belgium (8.18% impervious area and 3.89% effective impervious area), based on a combination of empirical and modelbased approaches. The effective impervious area, combined with the extent of the wastewater collection regions which do not coincide with the natural catchment boun...

  10. Ecohydrological modelling and integrated management planning in the catchment of the river Dommel

    NARCIS (Netherlands)

    Verkroost, A.W.M.; Olde Venterink, H.; Pieterse, N.M.; Schot, P.P.; Wassen, M.J.

    1998-01-01

    The EU-LIFE Dommel project aims at the development of methods for the combined use of landscape ecological models and socio-economic knowledge in the drawing up of integrated management plans for catchment areas of small trans-border rivers. These methods were developed and tested in the catchment a

  11. Vulnerabilidades sociais e juvenil nos mananciais da zona sul da cidade de São Paulo Social vulnerabilities and youth in the water catchment areas of the southern zone of the city of São Paulo

    Directory of Open Access Journals (Sweden)

    Elizabeth Borelli

    2012-06-01

    Full Text Available Este artigo é um produto parcial da pesquisa "Reflexos da Vulnerabilidade Socioambiental nas Manifestações Musicais dos Jovens Paulistanos da Periferia", identificando como recorte geográfico a periferia da Zona Sul da cidade de São Paulo. Trata-se de uma região que começou a se formar devido à ocupação populacional desordenada em áreas de manancial, onde a vulnerabilidade social é agravada por situações de risco e degradação ambiental, dado o adensamento das áreas de favelas, configurando um processo de exclusão ambiental e urbana. Temporalmente, a pesquisa parte da década de 1980, quando se expande o padrão de extensão da periferia e surgem as manifestações culturais nas periferias dos grandes centros urbanos. Nesta reflexão, a relação entre política e cultura é apresentada através da análise dos mecanismos de sociabilidade que articulam os jovens afrodescendentes das periferias em torno de intervenções culturais coletivas, como formas de criação e reprodução da sua realidade social.This article is a partial product of the study "Reflexes of the Socio-environmental Vulnerability in the Musical Manifestations of Paulista Youth from the Periphery," which focuses on the Southern Zone of the city of São Paulo. This is a region that took shape through the unordered occupation of water catchment areas, where social vulnerability is aggravated by situations of risk and environmental degradation, given the increased density of favela regions, establishing a process of environmental and urban exclusion. The study begins in the 1980s, when the pattern of extension of the periphery expanded and cultural manifestations arose in the peripheries of the large urban centers. In this reflection, the relationship between politics and culture is presented through the analysis of the mechanisms of sociability that articulate Afro-descendent youth from the periphery around collective cultural interventions, as forms of creation

  12. Comparison of subsurface connectivity in Alpine headwater catchments

    Science.gov (United States)

    Zuecco, Giulia; Rinderer, Michael; van Meerveld, Ilja; Penna, Daniele; Borga, Marco

    2016-04-01

    Saturation at the soil-bedrock interface or the rise of shallow groundwater into more permeable soil layers results in subsurface stormflow and can lead to hillslope-stream connectivity. Despite the importance of subsurface connectivity for streamflow and streamwater chemistry, the factors controlling its spatial and temporal variability are still poorly understood. This study takes advantage of networks of spatially-distributed piezometers in five small (stream when shallow groundwater was observed in the piezometer and it was connected by the edges to the stream. Weights were given to each piezometer based on Thiessen polygons to determine the area of the catchment that was connected to the stream. For the Swiss pre-alpine catchments the duration that nodes were connected to the stream was significantly correlated to the local and upslope site characteristics, such as the topographic wetness index, local slope and curvature. For the dolomitic catchment with the largest riparian zone, the time that nodes were connected to the stream was correlated with downslope site characteristics, such as the vertical distance to the nearest stream. The temporal changes in the area of the catchment that was connected to the stream reflected the streamflow dynamics for all catchments. Subsurface connectivity increased during rainfall events but there was a short delay compared to streamflow, suggesting that other processes (e.g. direct channel precipitation, runoff from near stream saturated areas) contributed to streamflow at the beginning of the event. Groundwater levels declined later and slower than streamflow, resulting in complex but mainly anti-clockwise hysteretic relations between streamflow and the area that was connected to the stream. Threshold-like relations between maximum connectivity and total stormflow and between maximum connectivity and the sum of total rainfall plus antecedent rainfall were more evident for the dolomitic catchments, where the riparian zone is

  13. Lessons learned for applying a paired-catchment approach in drought analysis

    Science.gov (United States)

    Van Loon, Anne; Rangecroft, Sally; Coxon, Gemma; Agustín Breña Naranjo, José; Van Ogtrop, Floris; Croghan, Danny; Van Lanen, Henny

    2017-04-01

    Ongoing research is looking to quantify the human impact on hydrological drought using observed data. One potentially suitable method is the paired-catchment approach. Paired catchments have been successfully used for quantifying the impact of human actions (e.g. forest treatment and wildfires) on various components of a catchment's water balance. However, it is unclear whether this method could successfully be applied to drought. In this study, we used a paired-catchment approach to quantify the effects of reservoirs, groundwater abstraction and urbanisation on hydrological drought in the UK, Mexico, and Australia. Following recommendations in literature, we undertook a thorough catchment selection and identified catchments of similar size, climate, geology, and topography. One catchment of the pair was affected by either reservoirs, groundwater abstraction or urbanisation. For the selected catchment pairs, we standardised streamflow time series to catchment area, calculated a drought threshold from the natural catchment and applied it to the human-influenced catchment. The underlying assumption being that the differences in drought severity between catchments can then be attributed to the anthropogenic activity. In some catchments we had local knowledge about human influences, and therefore we could compare our paired-catchment results with hydrological model scenarios. However, we experienced that detailed data on human influences usually are not well recorded. The results showed us that it is important to account for variation in average annual precipitation between the paired catchments to be able to transfer the drought threshold of the natural catchment to the human-influenced catchment. This can be achieved by scaling the discharge by the difference in annual average precipitation. We also found that the temporal distribution of precipitation is important, because if meteorological droughts differ between the paired catchments, this may mask changes caused

  14. Carbon redistribution by erosion processes in an intensively disturbed catchment

    Science.gov (United States)

    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

  15. Assessing Land Suitability for Rainwater Harvesting Using Geospatial Techniques: A Case Study of Njoro Catchment, Kenya

    Directory of Open Access Journals (Sweden)

    C. W. Maina

    2016-01-01

    Full Text Available Water demand increases as population increases leading to overexploitation of water resource. Consequently, there is need for improved water resources management complemented with rain water harvesting within the catchments. This study sought to assess land suitability for surface runoff harvesting using geospatial techniques. Land use/land cover maps of the area were derived from Landsat image. Land use and soils data were used in generating curve number map of the catchment. Lineaments greatly affect the storage depending on whether runoff is for surface storage or ground water recharge purposes. As a result, ArcGIS was used in delineating the lineaments from Digital Elevation Model (DEM of the catchment. Further, using weighted overlay the catchment was grouped into categories of restricted, not suitable, moderately suitable, suitable, or highly suitable. The study found that forest, agriculture, and built-up areas occupied about 39.42%, 36.32%, and 1.35% of catchment area, respectively. A large part of catchment was found to have curve number range of 82–89. About 50% of the catchment was found to fall within suitable and highly suitable categories. This implied that a great potential exists for rain water harvesting within the catchment.

  16. Design of a Rainwater Catchment System

    OpenAIRE

    Neil Cammardella

    2011-01-01

    Certain dimensions of a rainwater catchment and storage system were optimized using climatological and sociological data. Using only daily demand and average daily rain fall data, the following dimensions were optimized: 1) The horizontal roof area needed to collect the daily demand of water, 2) The tank size needed to store all the water collected during a heavy rain event, 3) When full, how long the tank will be able to provide water without rain, and 4) The diameter of the outlet flow orif...

  17. Sediment transport in steep forested catchments: the role of disturbance and scale

    Science.gov (United States)

    Hancock, Greg; Hugo, James; Webb, Ashley

    2016-04-01

    Sediment loads (both bedload and suspended sediment) are difficult to measure due to the time and equipment needed. However such data is needed to understand overall sediment transport rates, landscape evolution, effect of human disturbance as well as patterns and temporal response. There is a dearth of such data sets globally let along for Australia. Here we present the findings from 8 steep slope forested catchments dominated by headwater streams (size range 15-100 hectares) in south-eastern Australia where both bedload and suspended load have been measured over multiple years. The results demonstrate that suspended load is the dominant component. There appears to be no consistent suspended to bedload ratio for the catchments. The suspended sediment to bedload ratio appears to be catchment specific. There was no relationship between total load (or bedload/suspended load) and average catchment slope, stream length, shape or any geomorphic descriptor. Again this appears to be catchment specific. However catchment total load was found to be significantly related to catchment area and demonstrates strong log-log linear behaviour. Comparing these total loads with total load data from a nearby larger catchments (100km2 to 1000km2) demonstrates that there is a significant scaling relationship across all catchment sizes in this region. The scaling relationships found here are similar to those found globally and provide a unique insight into an understudied system. The data also provides the ability to assess sediment transport models and their reliability across different scales.

  18. A Vector-based Method for the Extraction of Catchment from Grid DEMs

    Institute of Scientific and Technical Information of China (English)

    ZHU Qing; TIAN Yixiang

    2005-01-01

    The methodology of catchment extraction especially from regular grid digital elevation models (DEMs) is briefly reviewed.Then an efficient algorithm, which combines vector process and traditional neighbourhood raster process, is designed for extracting the catchments and subcatchments from depressionless DEMs.The catchment area of each river in the grid DEM data is identified and delineated, then is divided into subcatchments as required.Compared to traditional processes, this method for identifying catchments focuses on the boundaries instead of the area inside the catchments and avoids the boundary intersection phenomena.Last, the algorithm is tested with a set of DEMs of different sizes, and the result proves that the computation efficiency and accuracy are better than existent methods.

  19. 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

  20. WWF Kikori Catchment Developmental Project, Papua New Guinea orchid survey

    NARCIS (Netherlands)

    Clements, M.A.; Harris, W.K.

    2002-01-01

    The World Wildlife Fund (Kikori Catchment Developmental Project, Papua New Guinea) has commenced field surveys of the Orchidaceae in the Lake Kutabu and Mt Bosavi areas of Papua New Guinea. The main purpose of the survey is to get a more accurate assessment of the orchids in the region. In a previou

  1. Computer system for catchment management: background, concepts and development

    CSIR Research Space (South Africa)

    Le Maitre, David C

    1993-01-01

    Full Text Available Managers of natural areas require a wide variety of up-to-date and accurate information and maps to manage their lands effectively. This paper reviews the objectives of conservation management, and the problems faced by mountain catchment managers...

  2. Hydrological Impacts of Urbanization of Two Catchments in Harare, Zimbabwe

    Directory of Open Access Journals (Sweden)

    Webster Gumindoga

    2014-12-01

    Full Text Available By increased rural-urban migration in many African countries, the assessment of changes in catchment hydrologic responses due to urbanization is critical for water resource planning and management. This paper assesses hydrological impacts of urbanization on two medium-sized Zimbabwean catchments (Mukuvisi and Marimba for which changes in land cover by urbanization were determined through Landsat Thematic Mapper (TM images for the years 1986, 1994 and 2008. Impact assessments were done through hydrological modeling by a topographically driven rainfall-runoff model (TOPMODEL. A satellite remote sensing based ASTER 30 metre Digital Elevation Model (DEM was used to compute the Topographic Index distribution, which is a key input to the model. Results of land cover classification indicated that urban areas increased by more than 600 % in the Mukuvisi catchment and by more than 200 % in the Marimba catchment between 1986 and 2008. Woodlands decreased by more than 40% with a greater decrease in Marimba than Mukuvisi catchment. Simulations using TOPMODEL in Marimba and Mukuvisi catchments indicated streamflow increases of 84.8 % and 73.6 %, respectively, from 1980 to 2010. These increases coincided with decreases in woodlands and increases in urban areas for the same period. The use of satellite remote sensing data to observe urbanization trends in semi-arid catchments and to represent catchment land surface characteristics proved to be effective for rainfall-runoff modeling. Findings of this study are of relevance for many African cities, which are experiencing rapid urbanization but often lack planning and design.

  3. Karst catchments exhibited higher degradation stress from climate change than the non-karst catchments in southwest China: An ecohydrological perspective

    Science.gov (United States)

    Liu, Meixian; Xu, Xianli; Wang, Dingbao; Sun, Alexander Y.; Wang, Kelin

    2016-04-01

    Karst landform represents about 10% of the continental area and plays key roles in water supplies for almost a quarter of the global population. Knowledge of ecohydrological responses of karst landform to climate change is critical for both water resources management and ecological protection in these regions. This study investigated the effects of karst landform on the elasticity of actual evapotranspiration (derived by the Budyko equation), estimated the contribution of climate change and evaluated the implications, on the basis of 13 typical catchments that have different karst landform coverages in southwest China. Catchment properties, including the vegetation coverage, portion of karst landform (POK), drainage area, surface roughness, mean topographic wetness index, mean slope, and mean aspect, were selected to test the influencing factors for the elasticity of actual evapotranspiration. Results indicate that POK is the most influencing factor for the elasticity of actual evapotranspiration in this region. Moreover, the actual evapotranspiration in karst catchments is more sensitive to precipitation change and less sensitive to the potential evapotranspiration change than that in the non-karst catchments. On the other hand, the contribution of climate change to actual evapotranspiration was generally negative in this region. Furthermore, relatively large negative contributions mainly occurred in the karst-dominated catchments, suggesting that the karst catchments were exposed to higher degradation stress brought by the climate change than that in non-karst catchments.

  4. Nitrate reduction in geologically heterogeneous catchments

    DEFF Research Database (Denmark)

    Refsgaard, Jens Christian; Auken, Esben; Bamberg, C.A.

    2014-01-01

    In order to fulfil the requirements of the EU Water Framework Directive nitrate load from agricultural areas to surface water in Denmark needs to be reduced by about 40%. The regulations imposed until now have been uniform, i.e. the same restrictions for all areas independent of the subsurface...... conditions. Studies have shown that on a national basis about 2/3 of the nitrate leaching from the root zone is reduced naturally, through denitrification, in the subsurface before reaching the streams. Therefore, it is more cost-effective to identify robust areas, where nitrate leaching through the root...... the entire catchment. However, as distributed models often do not include local scale hydrogeological heterogeneities, they are typically not able to make accurate predictions at scales smaller than they are calibrated. We present a framework for assessing nitrate reduction in the subsurface...

  5. Hydrological forecasting in catchments with glaciers

    OpenAIRE

    Nahat, Angèle

    2015-01-01

    The runoff forecast is crucial in Norway because the country bases most of its electricity from hydropower. The hydrological model has thus been improved for years in order to foresee the runoff in the best possible way. In Norway, there are many catchments with extensive water storage: glaciers. Those catchments represent a significant part of the catchments where hydropower is produced. Therefore knowing the right amount of outflow from a catchment with glaciers is essential but more challe...

  6. Runoff Responses to Forest Thinning at Plot and Catchment Scales in a Headwater Catchment Draining Japanese Cypress Forest

    Science.gov (United States)

    We examined the effect of forest thinning on runoff generation at plot and catchment scales in headwater basins draining a Japanese cypress (Chamaecyparis obtusa) forest. We removed 58.3% of the stems (corresponding to 43.2% of the basal area) in the treated headwater basin (catc...

  7. Water displacement by sewer infrastructure in the Grote Nete catchment, Belgium, and its hydrological regime effects

    Directory of Open Access Journals (Sweden)

    D. Vrebos

    2013-06-01

    Full Text Available Urbanization and especially impervious areas, in combination with wastewater treatment infrastructure, can exert several pressures on the hydrological cycle. These pressures were studied for the Grote Nete catchment in Belgium (8.18% impervious area and 3.89% effective impervious area, based on a combination of empirical and model-based approaches. The effective impervious area, combined with the extent of the wastewater collection regions which do not coincide with the natural catchment boundaries, was used as an indicator for the urbanization pressure. Our study revealed changes in the total upstream areas of the subcatchments between −16% and +3%, and in upstream impervious areas between −99% and +64%. These changes lead to important inter-catchment water transfers. Based on simulations with a physically-based and spatially-distributed hydrological catchment model, profound impacts of effective impervious area on infiltration and runoff were found. The model results show that the changes in impervious areas and related water displacements in and between catchments due to the installation of the wastewater treatment infrastructure severely impacted low flows, peak flows and seasonal trends. They moreover show that it is difficult, but of utmost importance, to incorporate these pressures and artificial processes in an accurate way during the development of hydrological models for urbanized catchments.

  8. Identifying fine sediment sources to alleviate flood risk caused by fine sediments through catchment connectivity analysis

    Science.gov (United States)

    Twohig, Sarah; Pattison, Ian; Sander, Graham

    2017-04-01

    Fine sediment poses a significant threat to UK river systems in terms of vegetation, aquatic habitats and morphology. Deposition of fine sediment onto the river bed reduces channel capacity resulting in decreased volume to contain high flow events. Once the in channel problem has been identified managers are under pressure to sustainably mitigate flood risk. With climate change and land use adaptations increasing future pressures on river catchments it is important to consider the connectivity of fine sediment throughout the river catchment and its influence on channel capacity, particularly in systems experiencing long term aggradation. Fine sediment erosion is a continuing concern in the River Eye, Leicestershire. The predominately rural catchment has a history of flooding within the town of Melton Mowbray. Fine sediment from agricultural fields has been identified as a major contributor of sediment delivery into the channel. Current mitigation measures are not sustainable or successful in preventing the continuum of sediment throughout the catchment. Identifying the potential sources and connections of fine sediment would provide insight into targeted catchment management. 'Sensitive Catchment Integrated Modelling Analysis Platforms' (SCIMAP) is a tool often used by UK catchment managers to identify potential sources and routes of sediment within a catchment. SCIMAP is a risk based model that combines hydrological (rainfall) and geomorphic controls (slope, land cover) to identify the risk of fine sediment being transported from source into the channel. A desktop version of SCIMAP was run for the River Eye at a catchment scale using 5m terrain, rainfall and land cover data. A series of SCIMAP model runs were conducted changing individual parameters to determine the sensitivity of the model. Climate Change prediction data for the catchment was used to identify potential areas of future connectivity and erosion risk for catchment managers. The results have been

  9. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Surficial Geology

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the area of surficial geology types in square meters compiled for every catchment of NHDPlus for the conterminous United States. The source...

  10. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Hydrologic Landscape Regions

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the area of Hydrologic Landscape Regions (HLR) compiled for every catchment of NHDPlus for the conterminous United States. The source data...

  11. Attributes for NHDPlus Catchments (Version 1.1) in the Conterminous United States: Bedrock Geology

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the area of bedrock geology types in square meters compiled for every catchment of NHDPlus for the conterminous United States. The source...

  12. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Level 3 Ecoregions

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the estimated area of level 3 ecological landscape regions (ecoregions), as defined by Omernik (1987), compiled for every catchment of...

  13. Attributes for NHDPlus Catchments (Version 1.1): Level 3 Nutrient Ecoregions, 2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the area of each level 3 nutrient ecoregion in square meters, compiled for every catchment of NHDPlus for the conterminous United States....

  14. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: Physiographic Provinces

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset represents the area of each physiographic province (Fenneman and Johnson, 1946) in square meters, compiled for every catchment of NHDPlus for the...

  15. Land degradation mapping for modelling of ecosystem benefit flows in the Inkomati catchment using remote sensing.

    CSIR Research Space (South Africa)

    Ramoelo, Abel

    2007-09-01

    Full Text Available , as well as nature conservation affect the natural ecosystems in different ways and magnitudes. The National Land Cover (NLC2000) project mapped degraded areas in the catchment, but the results lack a differentiation of magnitude of degradation...

  16. Catchment systems science and management: from evidence to resilient landscapes

    Science.gov (United States)

    Quinn, Paul

    2014-05-01

    There is an urgent need to reassess both the scientific understanding and the policy making approaches taken to manage flooding, water scarcity and pollution in intensively utilised catchments. Many European catchments have been heavily modified and natural systems have largely disappeared. However, working with natural processes must still be at the core of any future management strategy. Many catchments have greatly reduced infiltration rates and buffering capacity and this process needs to be reversed. An interventionist and holistic approach to managing water quantity and quality at the catchment scale is urgently required through the active manipulation of natural flow processes. Both quantitative (field experiments and modelling) and qualitative evidence (local knowledge) is required to demonstrate that catchment have become 'unhealthy'. For example, dense networks of low cost instrumentation could provide this multiscale evidence and, coupled with stakeholder knowledge, build a comprehensive understanding of whole system function. Proactive Catchment System Management is an interventionist approach to altering the catchment scale runoff regime through the manipulation of landscape scale hydrological flow pathways. Many of the changes to hydrological processes cannot be detected at the catchment scale as the primary causes of flooding and pollution. Evidence shows it is the land cover and the soil that are paramount to any change. Local evidence shows us that intense agricultural practices reduce the infiltration capacity through soil degradation. The intrinsic buffering capacity has also been lost across the landscape. The emerging hydrological process is one in which the whole system responds too quickly (driven by near surface and overland flow processes). The bulk of the soil matrix is bypassed during storm events and there is little or no buffering capacity in the riparian areas or in headwater catchments. The prospect of lower intensity farming rates is

  17. Dissolved nutrient exports from natural and human-impacted Neotropical catchments

    DEFF Research Database (Denmark)

    Gücker, Björn; Silva, Ricky C. S.; Graeber, Daniel

    2016-01-01

    Aim Neotropical biomes are highly threatened by land-use changes, but the catchment-wide biogeochemical effects are poorly understood. Here, we aim to compare exports of dissolved nitrogen (N) and phosphorus (P) from natural and human-impacted catchments in the Neotropics. Location Neotropics....... Methods We measured streamwater nutrient concentrations and exports in 20 south-eastern Brazilian catchments with different land uses (natural Cerrado/semi-deciduous forest, pasture, intensive agriculture and urban areas) and conducted a meta-analysis on nutrient exports from Neotropical catchments, both...... natural and human-impacted. Results Organic forms dominated dissolved nutrient exports in central/south-east Brazil in both natural and human-dominated catchments. Our meta-analysis suggests that there is wide geographic variability in the natural dominance of organic versus inorganic nutrient exports...

  18. 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.

  19. Controls of catchments` sub-storage contributions to dynamic water quality patterns in the stream network

    Science.gov (United States)

    Schuetz, Tobias; Maike Hegenauer, Anja

    2016-04-01

    Water quality is usually observed either continuously at a few stations within a catchment or with few snapshot sampling campaigns throughout the whole stream network. Although we know that the depletion of catchment sub-storages can vary throughout the stream network according to their actual water content (spatial variability of actual storage conditions can be caused amongst others by unevenly distributed rainfall, storage size or spatial differences in soil characteristics and land use), we know little about the impact of this process on spatial water quality patterns. For summer low flow recession periods, when stream water composition can be crucial for aquatic ecosystem conditions and the exceedance of water quality thresholds, knowledge on the controls of the dynamic interplay of catchment storages and stream water composition might improve water quality management and the implementation of corresponding mitigation measures. We studied this process throughout the stream network of a first-order agricultural headwater catchment in south-western Germany during two summer low flow recession periods. The underlying geology of the study area is a deep layer of aeolian loess, whilst the dominating soil is a silty calcaric regosol with gleizations in the colluvium. The land use in the catchment is dominated by viniculture (63 %) and arable crops (18 %). Due to the dense drainpipe network within the catchment we could identify 12 sub-catchments contributing during summer low flow recession periods to total stream discharge. We continuously observed discharge, electrical conductivity and water temperatures for 8 of the sub-catchments and at the catchment outlet. This data set was accomplished by 10 snapshot campaigns where we sampled for water temperatures, electrical conductivity, major ions, pH and O2 throughout the stream network. Using either discharge concentration relationships or time dependent functions, we derived continuous export rates for all measures in

  20. Understanding catchment scale sediment sources using geochemical tracers

    Science.gov (United States)

    Ferreira, Carla S. S.; Walsh, Rory P. D.; Shakesby, Richard A.; Steenhuis, Tammo S.; Ferreira, António J. D.; Coelho, Celeste O. A.

    2013-04-01

    It is well-established that urbanization leads to increased erosion (at least locally) as well as enhanced overland flow and streamflow peaks. Less is known about how the spatial distribution of erosion sources and scale of increases in erosion vary with the nature of urbanization in different climatic and socio-economic settings. This is important in order to prevent or reduce adverse impacts of erosion on downstream sedimentation, channel siltation and shifting, and river pollution. This paper adopts a sediment fingerprinting approach to assess the impact of partial urbanization and associated land-use change on sediment sources within a peri-urban catchment (6 km2), Ribeira dos Covões on the outskirts of the city of Coimbra in central Portugal. Urban land-use has increased from just 6% in 1958 to 30% in 2009. The urban pattern includes some well-defined urban residential centres, but also areas of discontinuous urban sprawl, including educational, health and small industrial facilities, numerous new roads and an enterprise park is under construction on the upper part of the catchment. The catchment has a wet Mediterranean climate and the lithology comprises sandstone in the west and limestone in the east. Soil depth is generally >40cm. The average slope angle is 8° (maximum 47°). Altitude ranges from 30m to 205m. A sediment fingerprinting approach was adopted to help establish the relative importance of sediment inputs from different urban areas. During September 2012 current bed-sediment samples (0-3 cm depth) were collected from 11 channel sites along the main stream and in different tributaries. At sites where bed-sediment was deeper, additional samples were taken at 3cm intervals to a maximum depth of around 42cm. In addition, overbank sediment samples (0-3cm depth) were collected at 11 locations around the catchment. All samples were oven-dried (at 38°C) and different particle size fractions (0.125-2mm, 0.063-0.125mm and chemical elements analysed

  1. 紫色丘陵区典型小流域非点源磷迁移特征%Characteristics of Non-point-source Phosphorus Losses in Some Representative Land-use Sub-catchments in the Hilly Area of Purple Soil

    Institute of Scientific and Technical Information of China (English)

    沈茜; 唐家良; 朱波

    2015-01-01

    Phosphorus forms and fluxes via hydrological pathways in typical rainfall events from different land uses in the hilly area of purple soil had been conducted by in-situ monitoring in some sub-catchments so as to understand“hotspot”and “critical time”for control of non-point-source pollution of phosphorus in a catchment.Rainfall-run-off process along with sediment yield,total phosphorus (TP),dissolved phosphorus (DP)and particulate phos-phorus (PP)concentrations and loadings were monitored in representative rain (small,medium,heavy and storm) events from sub-catchment of residence,forestland and cropland.The results showed that rainfall-runoff processes responded with land uses.In the residence sub-catchment,runoff started while rainfall reached 4mm,whereas, that started in much higher rainfall (20 mm)in the forestland and cropland sub-catchment,respectively.Runoff responded to rainfall rapidly at almost the same peak in the residence sub-catchment in medium,heavy and storm rain,while runoff delayed 20 -90 and 20 -120 min after rainfall in cropland and forestland sub-catchment,re-spectively.The mean runoff depth,runoff coefficient and sediment yield from residence sub-catchment were 22.4 mm,0.36 and 136.2 kg/hm2;while those were 9.5 mm,0.09 and 48.6 kg/hm2 from forestland and 12.3mm, 0.17 and 73.5 kg/hm2 from cropland,respectively.The water and soil loss from the residence is the most serious in the hilly area of purple soil.The concentration of total P (TP)and particulate phosphorus (PP)of runoff water from the residence and forestland sub-catchment reached peak quickly and decreased sharply,whereas,TP and PP of runoff water from cropland turned into a process with multi-peaks.The concentration of dissolved P (DP)of run-off water from the residence sub-catchment decreased when runoff discharge increased.DP of runoff water from the forestland sub-catchment increased during the runoff process.DP and phosphate (PO3-4 -P)concentrations of run-off from cropland

  2. Exploring the Linkage between Urban Flood Risk and Spatial Patterns in Small Urbanized Catchments of Beijing, China

    Science.gov (United States)

    Yao, Lei; Chen, Liding; Wei, Wei

    2017-01-01

    In the context of global urbanization, urban flood risk in many cities has become a serious environmental issue, threatening the health of residents and the environment. A number of hydrological studies have linked urban flooding issues closely to the spectrum of spatial patterns of urbanization, but relatively little attention has been given to small-scale catchments within the realm of urban systems. This study aims to explore the hydrological effects of small-scaled urbanized catchments assigned with various landscape patterns. Twelve typical residential catchments in Beijing were selected as the study areas. Total Impervious Area (TIA), Directly Connected Impervious Area (DCIA), and a drainage index were used as the catchment spatial metrics. Three scenarios were designed as different spatial arrangement of catchment imperviousness. Runoff variables including total and peak runoff depth (Qt and Qp) were simulated by using Strom Water Management Model (SWMM). The relationship between catchment spatial patterns and runoff variables were determined, and the results demonstrated that, spatial patterns have inherent influences on flood risks in small urbanized catchments. Specifically: (1) imperviousness acts as an effective indicator in affecting both Qt and Qp; (2) reducing the number of rainwater inlets appropriately will benefit the catchment peak flow mitigation; (3) different spatial concentrations of impervious surfaces have inherent influences on Qp. These findings provide insights into the role of urban spatial patterns in driving rainfall-runoff processes in small urbanized catchments, which is essential for urban planning and flood management. PMID:28264521

  3. Exploring the Linkage between Urban Flood Risk and Spatial Patterns in Small Urbanized Catchments of Beijing, China.

    Science.gov (United States)

    Yao, Lei; Chen, Liding; Wei, Wei

    2017-02-28

    In the context of global urbanization, urban flood risk in many cities has become a serious environmental issue, threatening the health of residents and the environment. A number of hydrological studies have linked urban flooding issues closely to the spectrum of spatial patterns of urbanization, but relatively little attention has been given to small-scale catchments within the realm of urban systems. This study aims to explore the hydrological effects of small-scaled urbanized catchments assigned with various landscape patterns. Twelve typical residential catchments in Beijing were selected as the study areas. Total Impervious Area (TIA), Directly Connected Impervious Area (DCIA), and a drainage index were used as the catchment spatial metrics. Three scenarios were designed as different spatial arrangement of catchment imperviousness. Runoff variables including total and peak runoff depth (Qt and Qp) were simulated by using Strom Water Management Model (SWMM). The relationship between catchment spatial patterns and runoff variables were determined, and the results demonstrated that, spatial patterns have inherent influences on flood risks in small urbanized catchments. Specifically: (1) imperviousness acts as an effective indicator in affecting both Qt and Qp; (2) reducing the number of rainwater inlets appropriately will benefit the catchment peak flow mitigation; (3) different spatial concentrations of impervious surfaces have inherent influences on Qp. These findings provide insights into the role of urban spatial patterns in driving rainfall-runoff processes in small urbanized catchments, which is essential for urban planning and flood management.

  4. Urbanization increased metal levels in lake surface sediment and catchment topsoil of waterscape parks

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hong-Bo [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Yu, Shen, E-mail: syu@iue.ac.cn [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Li, Gui-Lin [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Liu, Yi; Yu, Guang-Bin [Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Deng, Hong [Department of Environmental Sciences, Tiantong National Station of Forest Ecosystem, Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai 200062 (China); Wu, Sheng-Chun [State Key Laboratory in Marine Pollution, Biology and Chemistry Department, City University of Hong Kong, Hong Kong (China); Wong, Ming-Hung [Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Hong Kong (China)

    2012-08-15

    Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (< 63 {mu}m) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous. -- Highlights: Black-Right-Pointing-Pointer Obvious

  5. A water and sediment budget for a Mediterranean mountainous catchment (Southern Pyrenees)

    Science.gov (United States)

    Tuset, Jordi; Vericat, Damià; Batalla, Ramon J.

    2016-04-01

    Sediment transport in Mediterranean mountainous catchments is highly variable influenced principally by sediment availability, which in turn is controlled by the temporal and spatial variability of rainfall, runoff and land uses. In this paper we present the water and sediment budget of the Ribera Salada, a Mediterranean forest catchment located in the Catalan Pre-Pyrenees (NE Iberian Peninsula). The river drains an area of 224 km2. The data acquisition design is composed by five nested experimental sub-catchments. Each monitoring station registers discharge and suspended sediment transport continuously. Here we present the data obtained between 2012 and 2013, two contrasted hydrological years. These data allows to analyse the contribution of each sub-catchment to the total water and suspended sediment yield of the catchment at multiple temporal scales. Annual water yield in the catchment outlet varied between 15 and 31 hm3 y-1. Maximum peak flow in the outlet of the basin was 60.9 m3 s-1; equivalent to a specific discharge of 0.28 m3 s-1 km2. Results indicate that, hydrologically, the catchment can divided in two areas with contrasted regimes. The upper part of catchment is the wettest zone, where the water yield of each sub-catchment is in directly and positive correlated to its area. In contrast, the bottom of the valley has an ephemeral hydrological regime that only supplies water during important rainfall events. Annual suspended sediment load at the catchment outlet oscillated between 615 and 3415 t y-1, with an average value of 2015 t y-1 (i.e. 9.3 t km-2 y-1). In contrast to the water yield, most of the suspended sediment load (i.e. 80%) is supplied from the driest part of the catchment where sediment availability is greater and there is a greater connectivity between sediment sources and the channel network. The humid part of the catchment only yielded the 20% of the sediment load, where, as in the case of the water yield, sediment yield is directly and

  6. Pesticide uses and transfers in urbanised catchments.

    Science.gov (United States)

    Blanchoud, Hélène; Farrugia, Frédéric; Mouchel, Jean Marie

    2004-05-01

    An investigation on herbicide uses in two semi-urban catchments was performed simultaneously with sampling campaigns at six stations inside both watersheds from April to July 1998. Urban uses of herbicides exceeded agricultural uses, and transfer coefficients were also higher in urban areas. Therefore, the most used product in urban areas (diuron) was by far the most contaminating product. Householders accounted for 30% of all uses. The highest measured diuron concentration in water surface was 8.7 microg l(-1) due to its use on impervious surfaces. Compared to EEC standards for drinking water production (0.1 microg l(-1)), it is clear that suburban uses of herbicides may severely endanger drinking water production from river water.

  7. 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

    2017-02-10

    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.

  8. Modelling Pesticide Leaching At Column, Field and Catchment Scales I. Analysis of Soil Variability At Field and Catchment Scales

    Science.gov (United States)

    Gärdenäs, A.; Jarvis, N.; Alavi, G.

    The spatial variability of soil characteristics was studied in a small agricultural catch- ment (Vemmenhög, 9 km2) at the field and catchment scales. This analysis serves as a basis for assumptions concerning upscaling approaches used to model pesticide leaching from the catchment with the MACRO model (Jarvis et al., this meeting). The work focused on the spatial variability of two key soil properties for pesticide fate in soil, organic carbon and clay content. The Vemmenhög catchment (9 km2) is formed in a glacial till deposit in southernmost Sweden. The landscape is undulating (30 - 65 m a.s.l.) and 95 % of the area is used for crop production (winter rape, winter wheat, sugar beet and spring barley). The climate is warm temperate. Soil samples for or- ganic C and texture were taken on a small regular grid at Näsby Farm, (144 m x 144 m, sampling distance: 6-24 m, 77 points) and on an irregular large grid covering the whole catchment (sampling distance: 333 m, 46 points). At the field scale, it could be shown that the organic C content was strongly related to landscape position and height (R2= 73 %, p organic C content of hollows in the landscape is so high that they contribute little to the total loss of pesticides (Jarvis et al., this meeting). Clay content is also related to landscape position, being larger at the hilltop locations resulting in lower near-saturated hydraulic conductivity. Hence, macropore flow can be expected to be more pronounced (see also Roulier & Jarvis, this meeting). The variability in organic C was similar for the field and catchment grids, which made it possible to krige the organic C content of the whole catchment using data from both grids and an uneven lag distance.

  9. GAME THEORY AND K-MEANS ALGORITHM BASED COMPREHENSIVESUSCEPTIBILITY ANALYSIS OF CATCHMENTS FOR DEBRIS FLOWS INMOUNTAINOUS AREA OF BEIJING%基于博弈论和 K均值的北京山区小流域综合敏感性评价

    Institute of Scientific and Technical Information of China (English)

    史明远; 丁桂伶; 陈剑平; 张旭东

    2015-01-01

    Susceptibility analysis is an effective method to obtain characteristics of developments of catchment.There is a concomitant or alternate pattern of flash flood and debris flow in the mountainous area of Beijing.Consideration of hazard of debris flow alone cannot match the requirement of disaster prevention and control in themountainous area of Beijing if causing factors of flash flood are neglected.In this research,we adopt the evaluationfactors of flash flood in the susceptibility analysis of debris flow.Ten catchments in Beijing mountainous area areinvestigated.Analytic hierarchy process and entropy method are used for subjective and objective weighting.Combination weighting is calculated by game theory.The susceptibility of catchments is divided into slight,moderate and severe scale by Kmeans algorithm.Field investigation is used to check the results of scaling.Theresult shows that susceptibility analysis considering factors of flash flow fits the characteristics of disasters in themountainous area of Beijing.%敏感性分析是全面掌握小流域沟谷发展总体特征的有效途径。北京山区山洪泥石流灾害常相伴或交替发生,只考虑泥石流孕灾环境而忽视山洪致灾因子不能适应北京山区防灾减灾的客观要求。在分析泥石流敏感性基础上引入山洪评价因子,选取北京山区10条典型小流域,构建山洪泥石流综合评价体系,通过层次分析法对指标进行主观赋权,熵值法进行客观赋权,由博弈论给出各指标的组合权重值,由 K均值聚类法将小流域敏感性分为轻度、中度、重度3个等级。结合现场调查验证分类结果,表明山洪泥石流综合敏感性评价结果更适合北京山区的客观情况。

  10. Neighbourhood catchments: a new approach for achieving ownership and change in catchment and stream management.

    Science.gov (United States)

    Carroll, C; Rohde, K; Millar, G; Dougall, C; Stevens, S; Ritchie, R; Lewis, S

    2002-01-01

    The Neighbourhood Catchment approach integrates land and stream management practices at a property and through to a local catchment scale, links production and environmental goals, and is a building block to achieve ownership and change at a sub-catchment scale and larger. Research conducted in two 'focus' Neighbourhood Catchments has shown that land management practices that retain >30% soil cover reduce sediment movement to streams. The Neighbourhood Catchment approach engages both early and cautious adopters, and enables continuous improvement of resource management to take place, and be recorded at an individual property and local catchment scale.

  11. Estimation of nitrogen budgets for contrasting catchments at the landscape scale

    Directory of Open Access Journals (Sweden)

    E. Vogt

    2013-01-01

    Full Text Available A comprehensive assessment of nitrogen (N flows at the landscape scale is fundamental to understand spatial interactions in the N cascade and to inform the development of locally optimised N management strategies. To explore these interactions, complete N budgets were estimated for two contrasting hydrological catchments (dominated by agricultural grassland vs. semi-natural peat-dominated moorland, forming part of an intensively studied landscape in southern Scotland. Local scale atmospheric dispersion modelling and detailed farm and field inventories provided high resolution estimations of input fluxes. Direct agricultural inputs (i.e. grazing excreta, N2 fixation, organic and synthetic fertiliser accounted for most of the catchment N inputs, representing 82% in the grassland and 62% in the moorland catchment, while atmospheric deposition made a significant contribution, particularly in the moorland catchment, contributing 38% of the N inputs. The estimated catchment N budgets highlighted areas of key uncertainty, particularly N2 exchange and stream N export. The resulting N balances suggest that the study catchments have a limited capacity to store N within soils, vegetation and groundwater. The "catchment N retention", i.e. the amount of N which is either stored within the catchment or lost through atmospheric emissions, was estimated to be 13% of the net anthropogenic input in the moorland and 61% in the grassland catchment. These values contrast with regional scale estimates: Catchment retentions of net anthropogenic input estimated within Europe at the regional scale range from 50% to 90%, with an average of 82% (Billen et al., 2011. This study emphasises the need for detailed budget analyses to identify the N status of European landscapes.

  12. Groundwater as an emergency source for drought mitigation in the Crocodile River catchment, South Africa

    Directory of Open Access Journals (Sweden)

    F. E. F. Mussá

    2014-03-01

    and environmental damages to the society. In this study, we assess the drought intensity and severity and the groundwater potential to be used as a supplement source of water to mitigate drought impacts in the Crocodile River catchment, a water-stressed sub-catchment of the Incomati River catchment in South Africa. The research methodology consists mainly of three parts. First, the spatial and temporal variation of the meteorological and hydrological drought severity and intensity over the catchment were evaluated. The Standardized Precipitation Index (SPI was used to analyse the meteorological drought and the Standardized Runoff Index (SRI was used for the hydrological drought. Second, the water deficit in the catchment during the drought period was computed using a simple water balance method. Finally, a groundwater model was constructed in order to assess the feasibility of using groundwater as an emergency source for drought impact mitigation. Results show that the meteorological drought severity varies accordingly with the precipitation; the low rainfall areas are more vulnerable to severe meteorological droughts (lower and upper crocodile. Moreover, the most water stressed sub-catchments with high level of water uses but limited storage, such as the Kaap located in the middle catchment and the Lower Crocodile sub-catchments are those which are more vulnerable to severe hydrological droughts. The analysis of the potential groundwater use during droughts showed that a deficit of 97 Mm3 yr−1 could be supplied from groundwater without considerable adverse impacts on the river base flow and groundwater storage. Abstraction simulations for different scenarios of extremely severe droughts reveal that it is possible to use groundwater to cope with the droughts in the catchment. However, local groundwater exploitation in Nelspruit and White River sub-catchment will cause large drawdowns (> 10 m and high base flow reduction (> 20%. This case study shows that

  13. Use of remote sensing for hydrological parameterisation of Alpine catchments

    Directory of Open Access Journals (Sweden)

    H. Bach

    2003-01-01

    Full Text Available Physically-based water balance models require a realistic parameterisation of land surface characteristics of a catchment. Alpine areas are very complex with strong topographically-induced gradients of environmental conditions, which makes the hydrological parameterisation of Alpine catchments difficult. Within a few kilometres the water balance of a region (mountain peak or valley can differ completely. Hence, remote sensing is invaluable for retrieving hydrologically relevant land surface parameters. The assimilation of the retrieved information into the water balance model PROMET is demonstrated for the Toce basin in Piemonte/Northern Italy. In addition to land use, albedos and leaf area indices were derived from LANDSAT-TM imagery. Runoff, modelled by a water balance approach, agreed well with observations without calibration of the hydrological model. Keywords: PROMET, fuzzy logic based land use classification, albedo, leaf area index

  14. Hillslope hydrologic connectivity controls riparian groundwater turnover: Implications of catchment structure for riparian buffering and stream water sources

    Science.gov (United States)

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

    2010-01-01

    Hydrologic connectivity between catchment upland and near stream areas is essential for the transmission of water, solutes, and nutrients to streams. However, our current understanding of the role of riparian zones in mediating landscape hydrologic connectivity and the catchment scale export of water and solutes is limited. We tested the relationship between the...

  15. Impact on ecotourism by water pollution in the Olifants River catchment, South Africa

    CSIR Research Space (South Africa)

    Oberholster, Paul J

    2009-12-01

    Full Text Available . Olifants R. Olifants R. W ilge R. Sa alboomsp ru it R . Namibia Botswana Lesotho Swaziland Mozambique South Africa Bro nkh ors tsp ru it R . Steenkoolspruit R. T rich ard tsp ru it R . Vi sku ile R . Rie tsp rui t R... . T rich ard tsp ru it R . Figure 1. Sketch map showing the Upper Olifants River catchment with Lake Loskop. Inset map shows the area within South Africa; the dashed line separates the Wilge sub-catchment from the Olifants sub-catchment. SILnews 55...

  16. Urbanization increased metal levels in lake surface sediment and catchment topsoil of waterscape parks.

    Science.gov (United States)

    Li, Hong-Bo; Yu, Shen; Li, Gui-Lin; Liu, Yi; Yu, Guang-Bin; Deng, Hong; Wu, Sheng-Chun; Wong, Ming-Hung

    2012-08-15

    Lake surface sediment is mainly derived from topsoil in its catchment. We hypothesized that distribution of anthropogenic metals would be homogenous in lake surface sediment and the lake's catchment topsoil. Anthropogenic metal distributions (cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn)) in fourteen waterscape parks were investigated in surface sediments and catchment topsoils and possible source homogeneity was tested using stable Pb isotopic ratio analysis. The parks were located along an urbanization gradient consisting of suburban (SU), developing urban (DIU), developed urban (DDU), and central urban core (CUC) areas in Shanghai, China. Results indicated that surface lake sediments and catchment topsoils in the CUC parks were highly contaminated by the investigated anthropogenic metals. Total metal contents in surface sediment and topsoil gradually increased along the urbanization gradient from the SU to CUC areas. Generally, the surface sediments had greater total metal contents than their catchment topsoils. These results suggest that urbanization drives the anthropogenic metal enrichment in both surface sediment and its catchment topsoil in the waterscape parks. Soil fine particles (<63 μm) and surface sediments had similar enrichment ratios of metals, suggesting that surface runoff might act as a carrier for metals transporting from catchment to lake. Stable Pb isotope ratio analysis revealed that the major anthropogenic Pb source in surface sediment was coal combustion as in the catchment topsoil. Urbanization also correlated with chemical fractionation of metals in both surface sediment and catchment topsoil. From the SU to the CUC parks, amounts of labile metal fractions increased while the residual fraction of those metals remained rather constant. In short, urbanization in Shanghai drives anthropogenic metal distribution in environmental matrices and the sources were homogenous.

  17. Quantifying the hydrological impact of simulated changes in land use on peak discharge in a small catchment.

    Science.gov (United States)

    Kalantari, Zahra; Lyon, Steve W; Folkeson, Lennart; French, Helen K; Stolte, Jannes; Jansson, Per-Erik; Sassner, Mona

    2014-01-01

    A physically-based, distributed hydrological model (MIKE SHE) was used to quantify overland runoff in response to four extreme rain events and four types of simulated land use measure in a catchment in Norway. The current land use in the catchment comprises arable lands, forest, urban areas and a stream that passes under a motorway at the catchment outlet. This model simulation study demonstrates how the composition and configuration of land use measures affect discharge at the catchment outlet differently in response to storms of different sizes. For example, clear-cutting on 30% of the catchment area produced a 60% increase in peak discharge and a 10% increase in total runoff resulting from a 50-year storm event in summer, but the effects on peak discharge were less pronounced during smaller storms. Reforestation of 60% of the catchment area was the most effective measure in reducing peak flows for smaller (2-, 5- and 10-year) storms. Introducing grassed waterways reduced water velocity in the stream and resulted in a 28% reduction in peak flow at the catchment outlet for the 50-year storm event. Overall, the results indicate that the specific effect of land use measures on catchment discharge depends on their spatial distribution and on the size and timing of storm events.

  18. Identificação e implicações para a conservação do solo das fontes de sedimentos em bacias hidrográficas Identification and implications for soil conservation of sediment sources in catchment areas

    Directory of Open Access Journals (Sweden)

    Jean Paolo Gomes Minella

    2007-12-01

    Full Text Available Os sedimentos oriundos de áreas agrícolas são importante fonte de poluentes para os ecossistemas aquáticos. Existem várias fontes de sedimentos na escala de uma bacia hidrográfica rural, como lavouras, pastagens, florestas, rede fluvial e estradas. Cada uma tem características diferentes na magnitude de contribuição e potencial de contaminação. Identificar a origem dos sedimentos é fundamental na compreensão da taxa de emissão de sedimentos e no manejo dos sedimentos erodidos na escala de bacia. Este trabalho foi desenvolvido com o propósito de identificar as principais fontes de sedimentos de duas bacias rurais de cabeceira no Sul do Brasil, as quais são representativas do sistema agrário e das características fisiográficas da região. A metodologia utiliza a comparação entre os solos de diferentes fontes e os sedimentos em suspensão, usando traçadores naturais. A análise discriminante encontrou um grupo de variáveis capazes de distinguir as fontes de sedimentos. Com base na análise de classificação, as contribuições relativas de cada fonte nas bacias de Agudo e Arvorezinha foram, respectivamente: lavouras (68,3 e 55,5 %, estradas (28,1 e 37,6 % e rede fluvial (3,6 e 6,9 %. Os resultados mostram que, além da contribuição predominante das lavouras, as erosões nas estradas e na rede fluvial contribuem significativamente para produção total de sedimentos nas bacias, demonstrando a importância dessa informação para controle da erosão do solo e manejo dos sedimentos na escala de bacia hidrográfica.Sediments in agricultural areas represent a significant source of pollution of aquatic environments. There are many different sediment sources at the level of a rural catchment (e.g. crop fields, pastures, forests, river banks, and roads, with different magnitude of contribution and contaminant potential. The identification of the sediment origin is important to understand the sediment transport rate and the

  19. Assessing Land Suitability for Rainwater Harvesting Using Geospatial Techniques: A Case Study of Njoro Catchment, Kenya

    OpenAIRE

    Maina, C. W.; J. M. Raude

    2016-01-01

    Water demand increases as population increases leading to overexploitation of water resource. Consequently, there is need for improved water resources management complemented with rain water harvesting within the catchments. This study sought to assess land suitability for surface runoff harvesting using geospatial techniques. Land use/land cover maps of the area were derived from Landsat image. Land use and soils data were used in generating curve number map of the catchment. Lineaments grea...

  20. Modeling of matters removal from swampy catchment

    Science.gov (United States)

    Inishev, N. G.; Inisheva, L. I.

    2010-05-01

    This work shows the results of fixed study of geochemical conditions in the system of landscape oligotrophic profile at Vasyugan mire spurs, and also we make an approach to processes modelling of compounds removal from swampy catchment. During investigation of symbolic model of chemical matters removal from the surface of a catchment basin and their movement along the channel network it was taken into account that removal of chemical elements during the period of spring flood and rain high waters occur mainly with overland flow. During calculation of dissolved matters movement the following admissions take place: 1. The problem is solved at one-dimension set-up. Concentration of investigated components is taken as averaged one along the flow cross section or effective area of slope cross-section for overland runoff, i.e. it changes only lengthways and in time. 2. It is considered that dissolved matters spread due to movement of water and together with its particles. 3. Processes of water self-clarification are not considered. The model is calculated on the basis of discharge of the investigated ingredient, i.e. matter mass moving through the given flow cross-section into time unit. This is the peculiarity of the model. Matter removal together with water flow is determined if necessary. Everyday impurity consumptions and its concentration can be estimated at the outlet at the moment of time according to convolution integral. Estimation of overland runoff and water inflow into the channel network is based on the mathematic model of outflow formation from peatland areas which considers basic processes carrying out at catchment and basin channel network. Stored moisture estimation of snow cover is taken according to snow survey data before snow melting. Everyday water supply to the surface of water collection was determined according to the results of snow melt intensity estimation by the methods of temperature coefficient and water yield from snow (A.G. Kovzel). All

  1. Hydrological behaviour and water balance analysis for Xitiaoxi catchment of Taihu Basin

    Institute of Scientific and Technical Information of China (English)

    Xue Lijuan; Li Lijiao; Zhang Qi

    2008-01-01

    With the rapid social and economic development of the Taihu region, Taihu Lake now faces an increasingly severe eutrophication problem. Pollution from surrounding catchments contributes greatly to the eutrophication of water bodies in the region. Investigation of surface flow and associated mass transport for the Xitiaoxi catchment is of a significant degree of importance as the Xitiaoxi catchment is one of the major catchments within the Taihu region. A SWAT-based distributed hydrological model was established for the Xitiaoxi catchment. The model was calibrated and verified using hydrometeorological data from 1988 to 2001. The results indicate that the modeled daily and annual stream flow match the observed data both in the calibration period and the verification period, with a linear regression coefficient R2 and a coefficient e for modeleddaily stream flow greater than 0.8 at Hengtangcun and Fanjiacun gauge stations. The results show that the runoffprocess in the Xitiaoxi catchment is affected both by rainfall and human activities (e.g., reservoirs and polder areas). Moreover, the human activities weaken flood peaks more noticeably during rainstorms. The water balance analysis reveals the percentages of precipitation made up by surface flow, evapotranspiration, groundwater recharge and the change of soil storage, all of which are considered useful to the further understanding of the hydrological processes in the Xitiaoxi catchment. This study provides a good base for further studies in mass transport modeling and comparison of modeling results from similar hydrological models.

  2. Hydrological behaviour and water balance analysis for Xitiaoxi catchment of Taihu Basin

    Directory of Open Access Journals (Sweden)

    Li-juan XUE

    2008-09-01

    Full Text Available With the rapid social and economic development of the Taihu region, Taihu Lake now faces an increasingly severe eutrophication problem. Pollution from surrounding catchments contributes greatly to the eutrophication of water bodies in the region. Investigation of surface flow and associated mass transport for the Xitiaoxi catchment is of a significant degree of importance as the Xitiaoxi catchment is one of the major catchments within the Taihu region. A SWAT-based distributed hydrological model was established for the Xitiaoxi catchment. The model was calibrated and verified using hydrometeorological data from 1988 to 2001. The results indicate that the modeled daily and annual stream flow match the observed data both in the calibration period and the verification period, with a linear regression coefficient R2 and a coefficient e for modeled daily stream flow greater than 0.8 at Hengtangcun and Fanjiacun gauge stations. The results show that the runoff process in the Xitiaoxi catchment is affected both by rainfall and human activities (e.g., reservoirs and polder areas. Moreover, the human activities weaken flood peaks more noticeably during rainstorms. The water balance analysis reveals the percentages of precipitation made up by surface flow, evapotranspiration, groundwater recharge and the change of soil storage, all of which are considered useful to the further understanding of the hydrological processes in the Xitiaoxi catchment. This study provides a good base for further studies in mass transport modeling and comparison of modeling results from similar hydrological models.

  3. Catchment mixing processes and travel time distributions

    National Research Council Canada - National Science Library

    Botter, Gianluca

    2012-01-01

    ...) of travel, residence and evapotranspiration times, which are comprehensive descriptors of the fate of rainfall water particles traveling through catchments, and provide key information on hydrologic...

  4. A bottom up approach for engineering catchments through sustainable runoff management

    Science.gov (United States)

    Wilkinson, M.; Quinn, P. F.; Jonczyk, J.; Burke, S.

    2010-12-01

    There is no doubt that our catchments are under great stress. There have been many accounts around the world of severe flood events and water quality issues within channels. As a result of these, ecological habitats in rivers are also under pressure. Within the United Kingdom, all these issues have been identified as key target areas for policy. Traditionally this has been managed by a policy driven top down approach which is usually ineffective. A one ‘size fits all’ attitude often does not work. This paper presents a case study in northern England whereby a bottom up approach is applied to multipurpose managing of catchments at the source (in the order of 1-10km2). This includes simultaneous tackling of water quality, flooding and ecological issues by creating sustainable runoff management solutions such as storage ponds, wetlands, beaver dams and willow riparian features. In order to identify the prevailing issues in a specific catchment, full and transparent stakeholder engagement is essential, with everybody who has a vested interest in the catchment being involved from the beginning. These problems can then be dealt with through the use of a novel catchment management toolkit, which is transferable to similar scale catchments. However, evidence collected on the ground also allows for upscaling of the toolkit. The process gathers the scientific evidence about the effectiveness of existing or new measures, which can really change the catchment functions. Still, we need to get better at communicating the science to policy makers and policy therefore must facilitate a bottom up approach to land and water management. We show a test site for this approach in the Belford burn catchment (6km2), northern England. This catchment has problems with flooding and water quality. Increased sediment loads are affecting the nearby estuary which is an important ecological zone and numerous floods have affected the local village. A catchment engineering toolkit has been

  5. The role of climatic and terrain attributes in estimating baseflow recession in tropical catchments

    Directory of Open Access Journals (Sweden)

    J. L. Peña-Arancibia

    2010-07-01

    Full Text Available The understanding of low flows in rivers is paramount more than ever as demand for water increases on a global scale. At the same time, limited streamflow data to investigate this phenomenon, particularly in the tropics, makes the provision of accurate estimations in ungauged areas an ongoing research need. This paper analysed the potential of climatic and terrain attributes of 167 tropical and sub-tropical unregulated catchments to predict baseflow recession rates. Climatic attributes included annual and seasonal indicators of rainfall and potential evapotranspiration. Terrain attributes included indicators of catchment shape, morphology, land cover, soils and geology. Stepwise regression was used to identify the best predictors for baseflow recession coefficients (kbf. Mean annual rainfall (MAR and aridity index (AI were found to explain 49% of the spatial variation of kbf. The rest of climatic indices plus average catchment slope (SLO and tree cover were also good predictors, but co-correlated with MAR. Catchment elongation (CE, a measure of catchment shape, was also found to be statistically significant, although weakly correlated. An analysis of clusters of catchments of smaller size, showed that in these areas, presumably with some similarity of soils and geology due to proximity, residuals of the regression could be explained by SLO and CE. The approach used provides a~potential alternative for kbf parameterisation in ungauged areas.

  6. Catchment Management Agencies for poverty eradication in South Africa

    Science.gov (United States)

    Schreiner, Barbara; Van Koppen, Barbara

    This paper discusses the changes in water law in South Africa since the new dispensation. The focus is on the poverty dimensions of the early experiences of implementation of one of the components of the National Water Act: the establishment of Catchment Management Agencies (CMAs). From a diversity of recent experiences in decentralizing integrated water resources management, key areas emerge where future actions by the government are crucial to establish pro-poor, developmental CMAs.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Seasonal exports of phosphorus from intensively fertilised nested grassland catchments.

    Science.gov (United States)

    Lewis, Ciaran; Rafique, Rashad; Foley, Nelius; Leahy, Paul; Morgan, Gerard; Albertson, John; Kumar, Sandeep; Kiely, Gerard

    2013-09-01

    We carried out a one year (2002) study of phosphorus (P) loss from soil to water in three nested grassland catchments with known P input in chemical fertilizer and animal liquid slurry applications. Chemical fertilizer was applied to the grasslands between March and September and animal slurry was applied over the twelve months. The annual chemical P fertilizer applications for the 17 and 211 ha catchments were 16.4 and 23.7 kg P/ha respectively and the annual slurry applications were 10.7 and 14.0 kg P/ha, respectively. The annual total phosphorus (TP) export in stream-flow was 2.61, 2.48 and 1.61 kg P/ha for the 17, 211 and 1524 ha catchments, respectively, compared with a maximum permissible (by regulation) annual export of ca. 0.35 kg P/ha. The export rate (ratio of P export to P in land applications) was 9.6% and 6.6% from the 17 and 211 ha catchments, respectively. On average, 70% of stream flow and 85% of the P export occurred during the five wet months (October to February) indicating that when precipitation is much greater than evaporation, the hydrological conditions are most favourable for P export. However the soil quality and land use history may vary the results. Particulate P made up 22%, 43% and 37% of the TP export at the 17, 211 and 1524 ha catchment areas, respectively. As the chemical fertilizer was spread during the grass growth months (March to September), it has less immediate impact on stream water quality than the slurry applications. We also show that as the catchment scale increases, the P concentrations and P export decrease, confirming dilution due to increasing rural catchment size. In the longer term, the excess P from fertilizer maintains high soil P levels, an antecedent condition favourable to P loss from soil to water. This study confirms the significant negative water quality impact of excess P applications, particularly liquid animal slurry applications in wet winter months. The findings suggest that restricted P application in

  9. Seasonal exports of phosphorus from intensively fertilised nested grassland catchments

    Institute of Scientific and Technical Information of China (English)

    Ciaran Lewis; Rashad Rafique; Nelius Foley; Paul Leahy; Gerard Morgan; John Albertson; Sandeep Kumar

    2013-01-01

    We carried out a one year (2002) study of phosphorus (P) loss from soil to water in three nested grassland catchments with known P input in chemical fertilizer and animal liquid slurry applications.Chemical fertilizer was applied to the grasslands between March and September and animal slurry was applied over the twelve months.The annual chemical P fertilizer applications for the 17 and 211 ha catchments were 16.4 and 23.7 kg P/ha respectively and the annual slurry applications were 10.7 and 14.0 kg P/ha,respectively.The annual total phosphorus (TP) export in stream-flow was 2.61,2.48 and 1.61 kg P/ha for the 17,211 and 1524 ha catchments,respectively,compared with a maximum permissible (by regulation) annual export of ca.0.35 kg P/ha.The export rate (ratio of P export to P in land applications) was 9.6% and 6.6% from the 17 and 211 ha catchments,respectively.On average,70% of stream flow and 85% of the P export occurred during the five wet months (October to February) indicating that when precipitation is much greater than evaporation,the hydrological conditions are most favourable for P export.However the soil quality and land use history may vary the results.Particulate P made up 22%,43% and 37% of the TP export at the 17,211 and 1524 ha catchment areas,respectively.As the chemical fertilizer was spread during the grass growth months (March to September),it has less immediate impact on stream water quality than the slurry applications.We also show that as the catchment scale increases,the P concentrations and P export decrease,confirming dilution due to increasing rural catchment size.In the longer term,the excess P from fertilizer maintains high soil P levels,an antecedent condition favourable to P loss from soil to water.This study confirms the significant negative water quality impact of excess P applications,particularly liquid animal slurry applications in wet winter months.The findings suggest that restricted P application in wet months can

  10. The role of event water, a rapid shallow flow component, and catchment size in summer stormflow

    Science.gov (United States)

    Brown, V.A.; McDonnell, Jeffery J.; Burns, Douglas A.; Kendall, C.

    1999-01-01

    Seven nested headwater catchments (8 to 161 ha) were monitored during five summer rain events to evaluate storm runoff components and the effect of catchment size on water sources. Two-component isotopic hydrograph separation showed that event-water contributions near the time of peakflow ranged from 49% to 62% in the 7 catchments during the highest intensity event. The proportion of event water in stormflow was greater than could be accounted for by direct precipitation onto saturated areas. DOC concentrations in stormflow were strongly correlated with stream 18O composition. Bivariate mixing diagrams indicated that the large event water contributions were likely derived from flow through the soil O-horizon. Results from two-tracer, three-component hydrograph separations showed that the throughfall and O-horizon soil-water components together could account for the estimated contributions of event water to stormflow. End-member mixing analysis confirmed these results. Estimated event-water contributions were inversely related to catchment size, but the relation was significant for only the event with greatest rainfall intensity. Our results suggest that perched, shallow subsurface flow provides a substantial contribution to summer stormflow in these small catchments, but the relative contribution of this component decreases with catchment size.Seven nested headwater catchments (8 to 161 ha) were monitored during five summer rain events to evaluate storm runoff components and the effect of catchment size on water sources. Two-component isotopic hydrograph separation showed that event-water contributions near the time of peakflow ranged from 49% to 62% in the 7 catchments during the highest intensity event. The proportion of event water in stormflow was greater than could be accounted for by direct precipitation onto saturated areas. DOC concentrations in stormflow were strongly correlated with stream 18O composition. Bivariate mixing diagrams indicated that the

  11. Evaluation of catchment delineation methods for the medium-resolution National Hydrography Dataset

    Science.gov (United States)

    Johnston, Craig M.; Dewald, Thomas G.; Bondelid, Timothy R.; Worstell, Bruce B.; McKay, Lucinda D.; Rea, Alan; Moore, Richard B.; Goodall, Jonathan L.

    2009-01-01

    Different methods for determining catchments (incremental drainage areas) for stream segments of the medium-resolution (1:100,000-scale) National Hydrography Dataset (NHD) were evaluated by the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA). The NHD is a comprehensive set of digital spatial data that contains information about surface-water features (such as lakes, ponds, streams, and rivers) of the United States. The need for NHD catchments was driven primarily by the goal to estimate NHD streamflow and velocity to support water-quality modeling. The application of catchments for this purpose also demonstrates the broader value of NHD catchments for supporting landscape characterization and analysis. Five catchment delineation methods were evaluated. Four of the methods use topographic information for the delineation of the NHD catchments. These methods include the Raster Seeding Method; two variants of a method first used in a USGS New England study-one used the Watershed Boundary Dataset (WBD) and the other did not-termed the 'New England Methods'; and the Outlet Matching Method. For these topographically based methods, the elevation data source was the 30-meter (m) resolution National Elevation Dataset (NED), as this was the highest resolution available for the conterminous United States and Hawaii. The fifth method evaluated, the Thiessen Polygon Method, uses distance to the nearest NHD stream segments to determine catchment boundaries. Catchments were generated using each method for NHD stream segments within six hydrologically and geographically distinct Subbasins to evaluate the applicability of the method across the United States. The five methods were evaluated by comparing the resulting catchments with the boundaries and the computed area measurements available from several verification datasets that were developed independently using manual methods. The results of the evaluation indicated that the two

  12. Exploring calibration strategies of the SEDD model in two olive orchard catchments

    Science.gov (United States)

    Burguet, María; Taguas, Encarnación V.; Gómez, José Alfonso

    2017-08-01

    To optimize soil conservation strategies in catchments, it is required an accurate diagnosis of the areas contributing to soil erosion by using models such as SEDD (Sediment Delivery Distributed model). In this study, different calibration strategies of the SEDD model were explored to adapt its use in two olive catchments with different environmental features and managements. A data series of rainfall-runoff-sediment load, collected in the catchments for 6 years was used: i) to evaluate calibration strategies for different management and flow conditions through the analysis of the C and R factors, and ii) to describe the temporal patterns of sediment delivery ratio (SDR) at the event and annual scales. Different results and calibration approaches were derived from contrasting soil features and sediment dynamics in the catchments. A good model performance with simple calibration procedure was obtained for the catchment with clayey soil and a very active gully, whereas the model parameterisation was adapted to event features in the catchment with sandy soil where the importance of concentrated flow was minor. Mean annual values of SDR at the watershed scale (SDRw) were 110.1% for the catchment with clayey soil and 64.1% for that with sandy soils. SDRw values greater than 100% occurred in very humid years with precipitations 30% above the mean annual values. At the event scale, similar behaviours of SDR were observed. SDR > 100% were associated with the gully exporting sediments out from the clayey catchment, whereas this was done by rills and an ephemeral gully in the sandy catchment.

  13. 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...

  14. Hydropedological insights when considering catchment classification

    Directory of Open Access Journals (Sweden)

    J. Bouma

    2011-06-01

    Full Text Available Soil classification systems are analysed to explore the potential of developing classification systems for catchments. Soil classifications are useful to create systematic order in the overwhelming quantity of different soils in the world and to extrapolate data available for a given soil type to soils elsewhere with identical classifications. This principle also applies to catchments. However, to be useful, soil classifications have to be based on permanent characteristics as formed by the soil forming factors over often very long periods of time. When defining permanent catchment characteristics, discharge data would therefore appear to be less suitable. But permanent soil characteristics do not necessarily match with characteristics and parameters needed for functional soil characterization focusing, for example, on catchment hydrology. Hydropedology has made contributions towards the required functional characterization of soils as is illustrated for three recent hydrological catchment studies. However, much still needs to be learned about the physical behaviour of anisotropic, heterogeneous soils with varying soil structures during the year and about spatial and temporal variability. The suggestion is made therefore to first focus on improving simulation of catchment hydrology, possibly incorporating hydropedological expertise, before embarking on a catchment classification effort which involves major input of time and involves the risk of distraction. In doing so, we suggest to also define other characteristics for catchment performance than the traditionally measured discharge rates. Such characteristics may well be derived from societal issues being studied, as is illustrated for the Green Water Credits program.

  15. Spatial and Temporal Variation of Water Quality in the Bertam Catchment, Cameron Highlands, Malaysia.

    Science.gov (United States)

    Rasul, G

    2016-12-16

    The spatio-temporal variability of water quality associated with anthropogenic activities was studied for the Bertam River and its main tributaries within the Bertam Catchment, Cameron Highlands, Malaysia. A number of physico-chemical parameters of collected samples were analyzed to evaluate their spatio-temporal variability. Non-parametric statistical analysis showed significant temporal and spatial differences (p<0.05) in most of the parameters across the Catchment. Parameters except DO and COD displayed higher values in rainy season.The higher concentration of total suspended solids was caused due to massive soil erosion and sedimentation. Seasonal variations in contaminant concentrations are largely affected by precipitation and anthropogenic influences.Untreated domestic wastewater discharge as well as agricultural runoff significantly influenced the water quality. Poor agricultural practices and development activities at slope areas also affected the water quality within the Catchment. The analytical results provided a basis for protection of river environments and ecological restoration in mountainous Bertam Catchment.

  16. An estimation on budget and control of phosphorus in the Changjiang River catchment.

    Science.gov (United States)

    Shen, Zhi-Liang; Li, Zheng; Miao, Hui

    2012-11-01

    Based on field investigations in the Changjiang River mouth, rain sampling from the river's upper reaches to the mouth, historical data, and relevant literatures, the budget and major control factors of total phosphorus (TP) and dissolved inorganic phosphorus (DIP) in the river catchment were estimated and discussed from the catchment scale. It will supply a base for effective controlling P concentration in the Changjiang River and its mouth. Results show that the export fluxes of TP and DIP were mainly controlled by the river runoff. The TP and DIP in the Changjiang River came mainly from agricultural nonpoint source P losses from fertilizer and soil and point sources of industrial waste and residential sewage discharges. The export fluxes of TP and DIP in the river mouth were only 27.0% and 28.3% of the imports from the river catchment, respectively, suggesting that most of P were removed in transportation. A mass of freshwater marshes in the river catchment were the main areas to remove P. Significant increasing in utilization of fertilizer P and incessant increasing in water and soil loss areas were the primary reasons of agricultural nonpoint source P losses. How to decrease the agricultural nonpoint source P loss from the catchment scale is a key controlling P concentration in the Changjiang River and its mouth. The point source industrial waste P discharge has been primarily treated in the river catchment, but the residential sewage P discharge needs further control.

  17. Identifying Catchment-Scale Predictors of Coal Mining Impacts on New Zealand Stream Communities

    Science.gov (United States)

    Clapcott, Joanne E.; Goodwin, Eric O.; Harding, Jon S.

    2016-03-01

    Coal mining activities can have severe and long-term impacts on freshwater ecosystems. At the individual stream scale, these impacts have been well studied; however, few attempts have been made to determine the predictors of mine impacts at a regional scale. We investigated whether catchment-scale measures of mining impacts could be used to predict biological responses. We collated data from multiple studies and analyzed algae, benthic invertebrate, and fish community data from 186 stream sites, including un-mined streams, and those associated with 620 mines on the West Coast of the South Island, New Zealand. Algal, invertebrate, and fish richness responded to mine impacts and were significantly higher in un-mined compared to mine-impacted streams. Changes in community composition toward more acid- and metal-tolerant species were evident for algae and invertebrates, whereas changes in fish communities were significant and driven by a loss of nonmigratory native species. Consistent catchment-scale predictors of mining activities affecting biota included the time post mining (years), mining density (the number of mines upstream per catchment area), and mining intensity (tons of coal production per catchment area). Mining was associated with a decline in stream biodiversity irrespective of catchment size, and recovery was not evident until at least 30 years after mining activities have ceased. These catchment-scale predictors can provide managers and regulators with practical metrics to focus on management and remediation decisions.

  18. Identifying Catchment-Scale Predictors of Coal Mining Impacts on New Zealand Stream Communities.

    Science.gov (United States)

    Clapcott, Joanne E; Goodwin, Eric O; Harding, Jon S

    2016-03-01

    Coal mining activities can have severe and long-term impacts on freshwater ecosystems. At the individual stream scale, these impacts have been well studied; however, few attempts have been made to determine the predictors of mine impacts at a regional scale. We investigated whether catchment-scale measures of mining impacts could be used to predict biological responses. We collated data from multiple studies and analyzed algae, benthic invertebrate, and fish community data from 186 stream sites, including un-mined streams, and those associated with 620 mines on the West Coast of the South Island, New Zealand. Algal, invertebrate, and fish richness responded to mine impacts and were significantly higher in un-mined compared to mine-impacted streams. Changes in community composition toward more acid- and metal-tolerant species were evident for algae and invertebrates, whereas changes in fish communities were significant and driven by a loss of nonmigratory native species. Consistent catchment-scale predictors of mining activities affecting biota included the time post mining (years), mining density (the number of mines upstream per catchment area), and mining intensity (tons of coal production per catchment area). Mining was associated with a decline in stream biodiversity irrespective of catchment size, and recovery was not evident until at least 30 years after mining activities have ceased. These catchment-scale predictors can provide managers and regulators with practical metrics to focus on management and remediation decisions.

  19. Soil weathering rates in 21 catchments of the Canadian Shield

    Directory of Open Access Journals (Sweden)

    D. Houle

    2011-06-01

    Full Text Available Soil mineral weathering represents an essential source of nutrient base cation (Ca, Mg and K for forest growth in addition to provide a buffering power against precipitation acidity for soils and surface waters. Weathering rates of base cations were obtained for 21 catchments located within the temperate and the boreal forest of the Canadian Shield with the geochemical model PROFILE. Weathering rates ranged from 0.58 to 4.46 kmolc ha−1 yr−1 and their spatial variation within the studied area was mostly in agreement with spatial variations in soil mineralogy. Weathering rates of Ca and Mg were significantly correlated (r = 0.80 and 0.64 with their respective lake concentrations. Weathering rates of K and Na did not correlate with lake concentrations of K and Na. The modeled weathering rates for each catchment were also compared with estimations of net catchment exportations. The result show that modeled weathering rates of Ca were not significantly different than the net catchment exportations while modeled weathering rates of Mg were higher by 51 %. Larger differences were observed for K and Na weathering rates that were significantly different than net catchment exportations being 6.9 and 2.2 times higher than net exportations, respectively. The results for K were expected given its high reactivity with biotic compartments and suggest that most of the K produced by weathering reactions was retained within soil catchments and/or above ground biomass. This explanation does not apply to Na, however, which is a conservative element in forest ecosystems because of the insignificant needs of Na for soil microorganisms and above ground vegetations. It raises concern about the liability of the PROFILE model to provide reliable values of Na weathering rates. Overall, we concluded that the PROFILE model is powerful enough to reproduce spatial geographical gradients in weathering rates for relatively large areas

  20. Soil weathering rates in 21 catchments of the Canadian Shield

    Directory of Open Access Journals (Sweden)

    D. Houle

    2012-03-01

    Full Text Available Soil mineral weathering represents an essential source of nutrient base cation (Ca, Mg and K for forest growth in addition to provide a buffering power against precipitation acidity for soils and surface waters. Weathering rates of base cations were obtained for 21 catchments located within the temperate and the boreal forest of the Canadian Shield with the geochemical model PROFILE. Weathering rates ranged from 0.58 to 4.46 kmolc ha−1 yr−1 and their spatial variation within the studied area was mostly in agreement with spatial variations in soil mineralogy. Weathering rates of Ca and Mg were significantly correlated (r = 0.80 and 0.64 with their respective lake concentrations. Weathering rates of K and Na did not correlate with lake concentrations of K and Na. The modeled weathering rates for each catchment were also compared with estimations of net catchment exportations. The result show that modeled weathering rates of Ca were not significantly different than the net catchment exportations while modeled weathering rates of Mg were higher by 51%. Larger differences were observed for K and Na weathering rates that were significantly different than net catchment exportations being 6.9 and 2.2 times higher than net exportations, respectively. The results for K were expected given its high reactivity with biotic compartments and suggest that most of the K produced by weathering reactions was retained within soil catchments and/or above ground biomass. This explanation does not apply to Na, however, which is a conservative element in forest ecosystems because of the insignificant needs of Na for soil microorganisms and above ground vegetations. It raises concern about the liability of the PROFILE model to provide reliable values of Na weathering rates. Overall, we concluded that the PROFILE model is powerful enough to reproduce spatial geographical gradients in weathering rates for relatively large areas

  1. Sediment budget for Rediu reservoir catchment, North-Eastern Romania

    Science.gov (United States)

    Todosi, Cristian; Niculita, Mihai

    2016-04-01

    Sediment budgets are a useful tool for geomorphologic analysis, catchment management and environmental assessment, despite the uncertainties related to their assessment. We present the sediment budget construction and validation for a small catchment of 9.5319 kmp (953.19 ha) situated in the North-Eastern part of Romania. The Rediu reservoir was built between 1986 and 1988, on Rediu valley, a left tributary of Bahlui river, north-west from Iasi city. The catchment of the reservoir has 6.5 km in length and 2.5 km in maximum width, the altitudes decreasing from 170 m in the northern part, to 52 m in the southern part. The valley is symmetric, the altitude of the hillslopes going between 200 m to 75 m in one km length, in the transversal section with the maximum width. The floodplain is narrow having between 20 m to 210 m (in the area of confluence with Breazu tributary). The mean slope of the catchment is 6.4 degree, the maximum slope being 24.6 degrees. The length of channels which show banks of up to 2 m is 19.98 km. The land is used predominantly as crops (58.1 %), 16.7 % being covered by pastures (from which over half are eroded), 11.5 % percent of the catchment being covered by planted forests, 9.2 % by rural constructions and roads, 2.9 % by hayfields, 1.5 % by lakes and 0.1 % by orchards. Beside the Rediu reservoir, there are three ponds (15 771, 1761 and 751 sqm) in the catchment. We considered the trap efficiency for the reservoir and the ponds to be 95%. Aerial images from 1963, 1978 , 1984, 2005, 2008, 2010, 2012 and 2014 were used to assess the state of geomorphological processes before and after the reservoir construction. After 1970 a gully system situated in Breazu tributary sub-catchment and several active landslides along the main valley left side were forested. Beside these processes, soil erosion and human impact by constructions are the main processes generating sediment in the study area. The sediment yields were quantified by estimating the

  2. Hydrological dynamics of a Mediterranean catchment in a global change context. (Romanyac catchment, Cap de Creus, Girona, Spain)

    Science.gov (United States)

    Latron, J.; Pardini, G.; Gispert, M.; Llorens, P.

    2009-04-01

    Mediterranean regions are characterized by unevenly distributed water resources, and consequently a more precise knowledge of the main hydrological processes and their variability and changes is crucial for a better management of water resources. However, the lack of hydrological information and data in most areas of the Mediterranean basin greatly difficult the analyses of changes in water resources at relevant scales. In this context, the Soil Science Unit GRCT48 from the University of Girona is conducting an integrated study of hydrological response, soil erosion and soil degradation processes in fragile Mediterranean areas undergoing changes in use and management. The study area is located in the Cap de Creus Peninsula (NE Spain), where land abandonment has been the outstanding characteristic over the last decades. The area is covered by terraced soils, most of them abandoned, and stands for a representative Mediterranean environment. Current land cover is a mosaic of areas with different shrubs according to wildfire occurrence. Residual patches of cork and pine trees are also present as well as small extensions of pastures. Finally some localized areas of vineyards and olive trees are still cultivated. The approach is based on the complementary use of plot and catchment scales to assess the effect of land cover and land use change on physical, chemical and biological parameters of soil quality and on rainfall-runoff-erosion relationships. Along the study period, observed rainfall-runoff response at the plot scale was highly variable among sites but also for a given environment, depending on antecedent wetness conditions and rainfall characteristics. Overall, surface runoff responses were low in all environments. Soil loss associated to rainfall-runoff events showed very large variations among sites, and also for a given site, between the different rainfall events. At the catchment scale, preliminary results obtained from the monitoring, of three catchments of

  3. The role of climatic and terrain attributes in estimating baseflow recession in tropical catchments

    Directory of Open Access Journals (Sweden)

    J. L. Peña-Arancibia

    2010-11-01

    Full Text Available The understanding of low flows in rivers is paramount more than ever as demand for water increases on a global scale. At the same time, limited streamflow data to investigate this phenomenon, particularly in the tropics, makes the provision of accurate estimations in ungauged areas an ongoing research need. This paper analysed the potential of climatic and terrain attributes of 167 tropical and sub-tropical unregulated catchments to predict baseflow recession rates. Daily streamflow data (m3 s–1 from the Global River Discharge Center (GRDC and a linear reservoir model were used to obtain baseflow recession coefficients (kbf for these catchments. Climatic attributes included annual and seasonal indicators of rainfall and potential evapotranspiration. Terrain attributes included indicators of catchment shape, morphology, land cover, soils and geology. Stepwise regression was used to identify the best predictors for baseflow recession coefficients. Mean annual rainfall (MAR and aridity index (AI were found to explain 49% of the spatial variation of kbf. The rest of climatic indices and the terrain indices average catchment slope (SLO and tree cover were also good predictors, but co-correlated with MAR. Catchment elongation (CE, a measure of catchment shape, was also found to be statistically significant, although weakly correlated. An analysis of clusters of catchments of smaller size, showed that in these areas, presumably with some similarity of soils and geology due to proximity, residuals of the regression could be explained by SLO and CE. The approach used provides a potential alternative for kbf parameterisation in ungauged catchments.

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

    Science.gov (United States)

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

    2015-12-01

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

  5. Modeling nonlinear responses of DOC transport in boreal catchments in Sweden

    Science.gov (United States)

    Kasurinen, Ville; Alfredsen, Knut; Ojala, Anne; Pumpanen, Jukka; Weyhenmeyer, Gesa A.; Futter, Martyn N.; Laudon, Hjalmar; Berninger, Frank

    2016-07-01

    Stream water dissolved organic carbon (DOC) concentrations display high spatial and temporal variation in boreal catchments. Understanding and predicting these patterns is a challenge with great implications for water quality projections and carbon balance estimates. Although several biogeochemical models have been used to estimate stream water DOC dynamics, model biases common during both rain and snow melt-driven events. The parsimonious DOC-model, K-DOC, with 10 calibrated parameters, uses a nonlinear discharge and catchment water storage relationship including soil temperature dependencies of DOC release and consumption. K-DOC was used to estimate the stream water DOC concentrations over 5 years for eighteen nested boreal catchments having total area of 68 km2 (varying from 0.04 to 67.9 km2). The model successfully simulated DOC concentrations during base flow conditions, as well as, hydrological events in catchments dominated by organic and mineral soils reaching NSEs from 0.46 to 0.76. Our semimechanistic model was parsimonious enough to have all parameters estimated using statistical methods. We did not find any clear differences between forest and mire-dominated catchments that could be explained by soil type or tree species composition. However, parameters controlling slow release and consumption of DOC from soil water behaved differently for small headwater catchments (less than 2 km2) than for those that integrate larger areas of different ecosystem types (10-68 km2). Our results emphasize that it is important to account for nonlinear dependencies of both, soil temperature, and catchment water storage, when simulating DOC dynamics of boreal catchments.

  6. Influence of aquifer heterogeneity on karst hydraulics and catchment delineation employing distributive modeling approaches

    Directory of Open Access Journals (Sweden)

    S. Oehlmann

    2013-07-01

    Full Text Available Due to their heterogeneous nature, karst aquifers pose a major challenge for hydrogeological investigations. Important procedures like the delineation of catchment areas for springs are hindered by the unknown locations and hydraulic properties of highly conductive karstic zones. In this work numerical modeling was employed as a tool in delineating catchment areas of several springs within a karst area in southwestern Germany. For this purpose, different distributive modeling approaches were implemented in the Finite Element simulation software Comsol Multiphysics®. The investigation focuses on the question to which degree the effect of karstification has to be taken into account for accurately simulating the hydraulic head distribution and the observed spring discharges. The results reveal that the representation of heterogeneities has a large influence on the delineation of the catchment areas. Not only the location of highly conductive elements but also their geometries play a major role for the resulting hydraulic head distribution and thus for catchment area delineation. The size distribution of the karst conduits derived from the numerical models agrees with knowledge from karst genesis. It was thus shown that numerical modeling is a useful tool for catchment delineation in karst aquifers based on results from different field observations.

  7. Attributes for NHDPlus Catchments (Version 1.1) for the Conterminous United States: NLCD 2001 Land Use and Land Cover

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the estimated area of land use and land cover from the National Land Cover Dataset 2001 (LaMotte, 2008), compiled for every catchment of...

  8. Attributes for NHDPlus Catchments (Version 1.1) in the Conterminous United States: Artificial Drainage (1992) and Irrigation Types (1997)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tabular dataset represents the estimated area of artificial drainage for the year 1992 and irrigation types for the year 1997 compiled for every catchment of...

  9. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Physiographic Provinces

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tabular data set represents the area of each physiographic province (Fenneman and Johnson, 1946) in square meters, compiled for every MRB_E2RF1 catchment of...

  10. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Surficial Geology

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tabular data set represents the area of surficial geology types in square meters compiled for every MRB_E2RF1 catchment of selected Major River Basins (MRBs,...

  11. Tropical Montane Cloud Forests: Hydrometeorological variability in three neighbouring catchments with different forest cover

    Science.gov (United States)

    Ramírez, Beatriz H.; Teuling, Adriaan J.; Ganzeveld, Laurens; Hegger, Zita; Leemans, Rik

    2017-09-01

    Mountain areas are characterized by a large heterogeneity in hydrological and meteorological conditions. This heterogeneity is currently poorly represented by gauging networks and by the coarse scale of global and regional climate and hydrological models. Tropical Montane Cloud Forests (TMCFs) are found in a narrow elevation range and are characterized by persistent fog. Their water balance depends on local and upwind temperatures and moisture, therefore, changes in these parameters will alter TMCF hydrology. Until recently the hydrological functioning of TMCFs was mainly studied in coastal regions, while continental TMCFs were largely ignored. This study contributes to fill this gap by focusing on a TMCF which is located on the northern eastern Andes at an elevation of 1550-2300 m asl, in the Orinoco river basin highlands. In this study, we describe the spatial and seasonal meteorological variability, analyse the corresponding catchment hydrological response to different land cover, and perform a sensitivity analysis on uncertainties related to rainfall interpolation, catchment area estimation and streamflow measurements. Hydro-meteorological measurements, including hourly solar radiation, temperature, relative humidity, wind speed, precipitation, soil moisture and streamflow, were collected from June 2013 to May 2014 at three gauged neighbouring catchments with contrasting TMCF/grassland cover and less than 250 m elevation difference. We found wetter and less seasonally contrasting conditions at higher elevations, indicating a positive relation between elevation and fog or rainfall persistence. This pattern is similar to that of other eastern Andean TMCFs, however, the study site had higher wet season rainfall and lower dry season rainfall suggesting that upwind contrasts in land cover and moisture can influence the meteorological conditions at eastern Andean TMCFs. Contrasting streamflow dynamics between the studied catchments reflect the overall system response

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

    Science.gov (United States)

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

    2009-01-01

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

  13. Safeguarding the provision of ecosystem services in catchment systems.

    Science.gov (United States)

    Everard, Mark

    2013-04-01

    A narrow technocentric focus on a few favored ecosystem services (generally provisioning services) has led to ecosystem degradation globally, including catchment systems and their capacities to support human well-being. Increasing recognition of the multiple benefits provided by ecosystems is slowly being translated into policy and some areas of practice, although there remains a significant shortfall in the incorporation of a systemic perspective into operation management and decision-making tools. Nevertheless, a range of ecosystem-based solutions to issues as diverse as flooding and green space provision in the urban environment offers hope for improving habitat and optimization of beneficial services. The value of catchment ecosystem processes and their associated services is also being increasingly recognized and internalized by the water industry, improving water quality and quantity through catchment land management rather than at greater expense in the treatment costs of contaminated water abstracted lower in catchments. Parallel recognition of the value of working with natural processes, rather than "defending" built assets when catchment hydrology is adversely affected by unsympathetic upstream development, is being progressively incorporated into flood risk management policy. This focus on wider catchment processes also yields a range of cobenefits for fishery, wildlife, amenity, flood risk, and other interests, which may be optimized if multiple stakeholders and their diverse value systems are included in decision-making processes. Ecosystem services, particularly implemented as a central element of the ecosystem approach, provide an integrated framework for building in these different perspectives and values, many of them formerly excluded, into commercial and resource management decision-making processes, thereby making tractable the integrative aspirations of sustainable development. This can help redress deeply entrenched inherited assumptions

  14. Doing hydrology backwards in tropical humid catchments

    Science.gov (United States)

    Real Rangel, R.; Brena-Naranjo, J. A.; Pedrozo-Acuña, A.

    2015-12-01

    Top-down approaches in hydrology offer the possibility to predict water fluxes at the catchment scale based on the interpretation of the observed hydrological response at the catchment itself. Doing hydrology backwards (inferring precipitation and evapotranspiration rates at the catchment scale from streamflow measurements, see Kirchner (2009)) can be a useful methodology for estimating water fluxes at the catchment and regional scales. Previous studies using this inverse modeling approach have been performed in regions (UK, Switzerland, France, Eastern US) where energy-limited (in winter and early spring) and water-limited conditions (in summer) prevail during a large period of the year. However, such approach has not been tested in regions characterized by a quasi-constant supply of water and energy (e.g. humid tropics). The objective of this work is to infer annual rates of precipitation and evapotranspiration over the last decade in 10 catchments located in Mexico's tropical humid regions. Hourly discharge measurements during recession periods were analyzed and parameters for the nonlinear storage-discharge relationship of each catchment were derived. Results showed large variability in both catchment-scale precipitation and evapotranspiration rates among the selected study sites. Finally, a comparison was done between such estimates and those obtained from remotely-sensed data (TRMM for precipitation and MOD16 for evapotranspiration).

  15. Comparison of Water Flows in Four European Lagoon Catchments under a Set of Future Climate Scenarios

    Directory of Open Access Journals (Sweden)

    Cornelia Hesse

    2015-02-01

    Full Text Available Climate change is supposed to remarkably affect the water resources of coastal lagoons as they are highly vulnerable to changes occurring at their catchment and/or ocean or sea boundaries. Probable impacts of projected climate changes on catchment hydrology and freshwater input were assessed using the eco-hydrological model SWIM (Soil and Water Integrated Model for the drainage areas of four European lagoons: Ria de Aveiro (Portugal, Mar Menor (Spain, Tyligulskyi Liman (Ukraine and Vistula Lagoon (Poland/Russia under a set of 15 climate scenarios covering the time period until the year 2100. Climate change signals for all regions show continuously increasing trends in temperature, but various trends in precipitation. Precipitation is projected to decrease in two catchments on the Iberian Peninsula and increase in the Baltic region catchment, and does not show a clear trend in the catchment located near the Black Sea. The average projected changes in freshwater inputs reflect these changes in climate conditions, but often show variability between the scenarios, in future periods, and within the catchments. According to the individual degrees of water management influences in the four drainage basins, the climate sensitivity of river inflows is differently pronounced in each.

  16. Hydrological monitoring of experimental karst catchment Sutina - Karakašica

    Science.gov (United States)

    Bonacci, O.; Andrić, I.

    2012-04-01

    The Sutina - Karakašica is an ungauged karst catchment in southern part of Croatia with relative small area but with existing records of several events of flash flood that compromised the structures as bridge and roads along the stream. This poster gives an overview of the creation of the experimental catchment and establishment of the hydrological monitoring system which has for a goal a better understanding of runoff processes within the experimental karst area as well as flash flood occurrence analysis. The studied catchment is located in Dalmatia, southern part of Croatia, a region of Dinaric karst. Although it is very difficult to determine catchment borders in the karstic terrain, for the porpoises of the study the area of the catchment is estimated to 8 km2. The length of the stream flow up to the control cross section is 4.4 km. The highest point of the studied catchment area is on the 941 m a.s.l. and the lowest at the 300 m a.s.l. The geological settings of the catchment are characterized by the sedimentary rocks, mostly limestone and dolomites with discontinuities (cracks, and fractures) filled up with terra rossa and breccias. The presence of mudstone patches in the surface ensures the continuous surface flow of the studied stream. Some caves are also to be found in the catchment area. In the karst watersheds the occurrence of flash floods can be registered due to the exceptional meteorologic events during the year. The intensive rainfall in the short time period can trigger a flash flood that can induce overbank flow, immense changes in channel morphology and in sediment distribution. In order to produce a hydrological model that could predict the events of flash flood in the studied area, a continuous monitoring of meteorological and hydrological parameters in the catchment is established. The predictions of exceptional flooding events derived from a useful hydrological model based on the study site can be used further on to quantify the possible

  17. Historic change in catchment land use and metal loading to Sydney estuary, Australia (1788-2010).

    Science.gov (United States)

    Birch, G F; Lean, J; Gunns, T

    2015-09-01

    Sydney estuary has a long history of environmental degradation and is one of the most modified water ways in Australia due to a highly urbanised catchment (~77 %) and a high population (4.6 million). The objectives of the present study were to map historical land use change from European settlement (1788) to 2010 to determine catchment evolutionary pathways and to estimate catchment loading (total suspended solids, Cu, Pb and Zn) to the estuary over this period. Land use distribution in Sydney catchment, determined for seven time horizons over this period, indicated that a substantial increase in residential land use through subdivision of large estates and an increase in road area resulted in a marked increase in metal loading to Sydney estuary between 1892 and 1936. The decline in industrial activity from a maximum in 1978 (3.9 %) to 1.8 % in 2010 and the introduction of unleaded fuel during this time was accompanied by reduction in metal loading to the estuary. Land use time horizon maps enabled the creation of novel, ternary diagrams to represent temporal evolution in catchment land use. The 15 sub-catchments of Sydney estuary were combined into three major catchment categories, i.e., urban, dense urban and commercial. Present-day annual discharge of stormwater from the Sydney catchment was calculated to be 466,000 ML and annual loadings of total suspended sediment (TSS), Cu, Pb and Zn in tonnes were 49,239, 27, 37 and 57, respectively. Stormwater has superseded industry as the main source of anthropogenic metals to this estuary in recent times.

  18. The impact of forest regeneration on streamflow in 12 meso-scale humid tropical catchments

    Directory of Open Access Journals (Sweden)

    H. E. Beck

    2013-03-01

    Full Text Available Although regenerating forests make up an increasingly large portion of humid tropical landscapes, comparatively little is known of their water use and effects on streamflow (Q. Since the 1950s the island of Puerto Rico has experienced widespread abandonment of pastures and agricultural lands, followed by forest regeneration. This paper examines the possible impacts of forest regeneration on several Q metrics for 12 meso-scale catchments (23–346 km2; mean precipitation 1720–3422 mm yr−1 with long (33–51 yr and simultaneous records for Q, precipitation (P, potential evapotranspiration (PET, and land cover. A simple spatially-lumped, conceptual rainfall-runoff model that uses daily P and PET time series as inputs (HBV-light was used to simulate Q for each catchment. Annual time series of observed and simulated values of four Q metrics were calculated. A least-squares trend was fitted through annual time series of the residual difference between observed and simulated time series of each Q metric. From this the total cumulative change  was calculated, representing the change in each metric after controlling for climate variability and water storage carry-over effects between years. Negative values of  were found for most catchments and Q metrics, suggesting enhanced actual evapotranspiration overall following forest regeneration. However, correlations between changes in urban or forest area and values of  were insignificant (p ≥ 0.389 for all Q metrics. This suggests there is no convincing evidence that changes in the chosen Q metrics in these Puerto Rican catchments can be ascribed to changes in urban or forest area. The present results are in line with previous studies of meso- and macro-scale (sub-tropical catchments, which generally found no significant change in Q that can be attributed to changes in forest cover. Possible explanations for the apparent lack of a clear signal may include: errors in the land-cover, climate, Q

  19. Flow processes on the catchment scale - modeling of initial structural states and hydrological behavior in an artificial exemplary catchment

    Science.gov (United States)

    Maurer, Thomas; Caviedes-Voullième, Daniel; Hinz, Christoph; Gerke, Horst H.

    2017-04-01

    Landscapes that are heavily disturbed or newly formed by either natural processes or human activity are in a state of disequilibrium. Their initial development is thus characterized by highly dynamic processes under all climatic conditions. The primary distribution and structure of the solid phase (i.e. mineral particles forming the pore space) is one of the decisive factors for the development of hydrological behavior of the eco-hydrological system and therefore (co-) determining for its - more or less - stable final state. The artificially constructed ‚Hühnerwasser' catchment (a 6 ha area located in the open-cast lignite mine Welzow-Süd, southern Brandenburg, Germany) is a landscape laboratory where the initial eco-hydrological development is observed since 2005. The specific formation (or construction) processes generated characteristic sediment structures and distributions, resulting in a spatially heterogeneous initial state of the catchment. We developed a structure generator that simulates the characteristic distribution of the solid phase for such constructed landscapes. The program is able to generate quasi-realistic structures and sediment compositions on multiple spatial levels (1 cm up to 100 m scale). The generated structures can be i) conditioned to actual measurement values (e.g., soil texture and bulk distribution); ii) stochastically generated, and iii) calculated deterministically according to the geology and technical processes at the excavation site. Results are visualized using the GOCAD software package and the free software Paraview. Based on the 3D-spatial sediment distributions, effective hydraulic van-Genuchten parameters are calculated using pedotransfer functions. The hydraulic behavior of different sediment distribution (i.e. versions or variations of the catchment's porous body) is calculated using a numerical model developed by one of us (Caviedes-Voullième). Observation data are available from catchment monitoring are available

  20. Propagation of drought in a groundwater fed catchment, the Pang in UK

    NARCIS (Netherlands)

    Tallaksen, L.; Hisdal, H.; Lanen, van H.A.J.

    2006-01-01

    Regional drought characteristics, such as the area covered by drought and the total deficit over that area, are important measures of the severity of a drought event. Gridded, monthly data from the Pang catchment, UK, are analysed here to study the spatial aspects of the drought as it propagates

  1. Propagation of drought in a groundwater fed catchment, the Pang in UK

    NARCIS (Netherlands)

    Tallaksen, L.; Hisdal, H.; Lanen, van H.A.J.

    2006-01-01

    Regional drought characteristics, such as the area covered by drought and the total deficit over that area, are important measures of the severity of a drought event. Gridded, monthly data from the Pang catchment, UK, are analysed here to study the spatial aspects of the drought as it propagates fro

  2. Modelling catchment-scale erosion patterns in the East African Highlands

    NARCIS (Netherlands)

    Vigiak, O.; Okoba, B.O.; Sterk, G.; Groenenberg, S.

    2005-01-01

    Prompt location of areas exposed to high erosion is of the utmost importance for soil and water conservation planning. Erosion models can be useful tools to locate sources of sediment and areas of deposition within a catchment, but the reliability of model predictions of spatial patterns of erosion

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

    Science.gov (United States)

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

    2017-06-01

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

  4. Integration of spatial datasets to support the review of hydrometric networks and the identification of representative catchments

    Directory of Open Access Journals (Sweden)

    C. L. R. Laize

    2004-01-01

    Full Text Available The rapidly growing demand for river flow data has increased pressure on hydrometric monitoring programmes to match a wide range of application-focused information needs, in particular, the identification of representative catchments. This paper investigates a novel methodology based on a Geographical Information System to support cost-effective hydrometric network management and information delivery. Raster datasets are integrated as matrices describing the relationship between variables within any given area. Matrices are then compared to index how representative catchments are of a specified reference area. Using south-east Scotland as the reference area, four applications illustrate the methodology’s potential to address a variety of issues (e.g. network rationalisation, selection of impact catchments, identification of new gauging sites. The method is implemented using elevation and land-use datasets. Keywords: spatial information, Geographical Information System, hydrometry, network management, network rationalisation, representative catchment, regionalisation

  5. Potential possibilities of water retention in agricultural loess catchments

    Directory of Open Access Journals (Sweden)

    Zubala Tomasz

    2016-09-01

    Full Text Available The growing water deficit and the increased demand for water, as well as economic problems and inadequate spatial planning in many regions indicate a necessity of developing more effective rules of programming and realisation of works concerning the water management in small catchments. The paper presents a sample analysis of the possibilities of increasing water retention in the agricultural loess catchments with periodic streams. The scope of the study included the determination of physical parameters of selected sub-catchments (geometry, soil cover, land use, etc. and of the sources of threat to water resources, resulting from construction and geomorphological conditions. Pre-design assumptions of dammings were developed, taking into account anti-erosion protective measures, and treatments increasing the landscape retention of water were proposed. Creating surface retention objects should be an important source of water in simplified agroecosystems, especially in regions, where productivity to a great extent depends on natural weather conditions. Proper management of the fourth-order loess basin of the Ciemięga River (area of about 150 km2, the presence of 50 lateral valleys could give a temporary reservoir retention reaching 500 thousand m3. Farmers should be encouraged to seek “own water sources” (including the accumulation of water within wasteland, using appropriate economic instruments (tax reliefs for the documented volume of retained water, e.g. in small retention reservoirs.

  6. a Study of Urban Stormwater Modeling Approach in Singapore Catchment

    Science.gov (United States)

    Liew, S. C.; Liong, S. Y.; Vu, M. T.

    2011-07-01

    Urbanization has the direct effect of increasing the amount of surface runoff to be discharged through man-made drainage systems. Thus, Singapore's rapid urbanization has drawn great attention on flooding issues. In view of this, proper stormwater modeling approach is necessary for the assessment planning, design, and control of the storm and combines sewerage system. Impacts of urbanization on surface runoff and catchment flooding in Singapore are studied in this paper. In this study, the application of SOBEK-urban 1D is introduced on model catchments and a hypothetical catchment model is created for simulation purpose. Stormwater modeling approach using SOBEK-urban offers a comprehensive modeling tool for simple or extensive urban drainage systems consisting of sewers and open channels despite its size and complexity of the network. The findings from the present study show that stormwater modeling is able to identify flood area and the impact of the anticipated sea level on urban drainage network. Consequently, the performance of the urban drainage system can be improved and early prevention approaches can be carried out.

  7. Creating a catchment scale perspective for river restoration

    Science.gov (United States)

    Benda, L.; Miller, D.; Barquín, J.

    2011-09-01

    One of the major challenges in river restoration is to identify the natural fluvial landscape in catchments with a long history of river control. Intensive land use on valley floors often predates the earliest remote sensing: levees, dikes, dams, and other structures alter valley-floor morphology, river channels and flow regimes. Consequently, morphological patterns indicative of the fluvial landscape including multiple channels, extensive floodplains, wetlands, and fluvial-riparian and tributary-confluence dynamics can be obscured, and information to develop appropriate and cost effective river restoration strategies can be unavailable. This is the case in the Pas River catchment in northern Spain (650 km2), in which land use and development have obscured the natural fluvial landscape in many parts of the basin. To address this issue we used computer tools to examine the spatial patterns of fluvial landscapes that are associated with five domains of hydro-geomorphic processes and landforms. Using a 5-m digital elevation model, valley-floor surfaces were mapped according to elevation above the channel and proximity to key geomorphic processes. The predicted fluvial landscape is patchily distributed according to hillslope and valley topography, river network structure, and channel elevation profiles. The vast majority of the fluvial landscape in the main segments of the Pas River catchment is presently masked by human infrastructure, with only 15% not impacted by river control structures and development. The reconstructed fluvial landscape provides a catchment scale context to support restoration planning, in which areas of potential ecological productivity and diversity could be targeted for in-channel, floodplain and riparian restoration projects.

  8. 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.

  9. Creating a catchment scale perspective for river restoration

    Directory of Open Access Journals (Sweden)

    L. Benda

    2011-09-01

    Full Text Available One of the major challenges in river restoration is to identify the natural fluvial landscape in catchments with a long history of river control. Intensive land use on valley floors often predates the earliest remote sensing: levees, dikes, dams, and other structures alter valley-floor morphology, river channels and flow regimes. Consequently, morphological patterns indicative of the fluvial landscape including multiple channels, extensive floodplains, wetlands, and fluvial-riparian and tributary-confluence dynamics can be obscured, and information to develop appropriate and cost effective river restoration strategies can be unavailable. This is the case in the Pas River catchment in northern Spain (650 km2, in which land use and development have obscured the natural fluvial landscape in many parts of the basin. To address this issue we used computer tools to examine the spatial patterns of fluvial landscapes that are associated with five domains of hydro-geomorphic processes and landforms. Using a 5-m digital elevation model, valley-floor surfaces were mapped according to elevation above the channel and proximity to key geomorphic processes. The predicted fluvial landscape is patchily distributed according to hillslope and valley topography, river network structure, and channel elevation profiles. The vast majority of the fluvial landscape in the main segments of the Pas River catchment is presently masked by human infrastructure, with only 15% not impacted by river control structures and development. The reconstructed fluvial landscape provides a catchment scale context to support restoration planning, in which areas of potential ecological productivity and diversity could be targeted for in-channel, floodplain and riparian restoration projects.

  10. Morphology, geology and water quality assessment of former tin mining catchment.

    Science.gov (United States)

    Ashraf, Muhammad Aqeel; Maah, Mohd Jamil; Yusoff, Ismail

    2012-01-01

    Bestari Jaya, former tin mining catchment covers an area of 2656.31 hectares comprised of four hundred and forty-two different-size lakes and ponds. The present study area comprise of 92 hectares of the catchment that include four large size lakes. Arc GIS version 9.2 used to develop bathymetric map, Global Positioning System (GPS) for hydrographical survey and flow meter was utilized for water discharge analysis (flow routing) of the catchment. The water quality parameters (pH, temperature, electric conductivity, dissolved oxygen DO, total dissolved solids TDS, chlorides, ammonium, nitrates) were analyzed by using Hydrolab. Quality assurance (QA) and quality control (QC) procedures were strictly followed throughout the field work and data analysis. Different procedures were employed to evaluate the analytical data and to check for possible transcription or dilution errors, changes during analysis, or unusual or unlikely values. The results obtained are compared with interim national water quality standards for Malaysia indicates that water quality of area is highly degraded. It is concluded that Bestri Jaya ex-mining catchment has a high pollution potential due to mining activities and River Ayer Hitam, recipient of catchment water, is a highly polluted river.

  11. Manyame Catchment Council: a review of the reform of the water sector in Zimbabwe

    Science.gov (United States)

    Latham, C. J. K.

    The paper is a review of the reform process in the Manyame Catchment (one of the seven gazetted catchments that cover Zimbabwe). A critical analysis is made of the minutes of meeting of the council and of one sub-catchment council. A review is also undertaken of informal communication amongst stakeholders both before and after the promulgation of the new act. A critical analysis is made of the major issues of concern to stakeholders. This in turn reveals a number of areas of concern to academics and practitioners in the arena of community based common property resource management. These include issues of levels of management, scale, spatial and jurisdictional boundaries and the whole spectrum of issues thrown up when studying concerns over decentralization and devolution of authority. Of special interest in this regard is how this study highlights the way state bureaucrats have fashioned the act to protect their central positions in catchment management. Another area that receives critical review is the institutional overlap (spatial and jurisdictional) exemplified by catchment councils and rural district councils. Finally conclusions are drawn both in the area of practical guidelines for the improvement of the process of reform as well as offering some tentative suggestions for research topics.

  12. Identification of septic system effluent in ground water using small catchment hydrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Foster, M.B.J.; Alexander, E.C. Jr. (Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Geology and Geophysics)

    1992-01-01

    In many areas the contribution of septic system effluent to ground water contamination is still uncertain because of ambiguous provenance of chemical constituents. The problem is to establish a diagnostic chemical signature for the septic system effluent. Chlorides, nitrogen isotopes and optical brighteners have all been used as single constituent tracers for this purpose. These tracers tend to have limited range of application and cannot resolve ambiguity in areas with multiple potential contaminant sources. The authors addressed this problem using eight major ions to characterize the ground water chemistry, graphically or statistically. They identify the chemical signatures of septic system effluent and other non-point source contamination from the ground water chemistry of small ground water catchments overlain by single or very restricted land use types. They studied five small catchments near Rochester, Minnesota to isolate pre-development and non-septic system components of the ground water chemistry. Five small isolated hills were selected each with a distinct land-use type; natural forest, agricultural, unsewered residential, mixed agricultural/residential and fully sewered residential. The results show that Piper diagrams and statistical analysis can be used to define chemical signatures for the unsewered residential area using septic systems, the natural forest, and the agricultural catchments. The signatures of the mixed agriculture/residential and the fully sewered catchments are very similar to that of the agricultural catchment.

  13. Morphology, Geology and Water Quality Assessment of Former Tin Mining Catchment

    Science.gov (United States)

    Ashraf, Muhammad Aqeel; Maah, Mohd. Jamil; Yusoff, Ismail

    2012-01-01

    Bestari Jaya, former tin mining catchment covers an area of 2656.31 hectares comprised of four hundred and forty-two different-size lakes and ponds. The present study area comprise of 92 hectares of the catchment that include four large size lakes. Arc GIS version 9.2 used to develop bathymetric map, Global Positioning System (GPS) for hydrographical survey and flow meter was utilized for water discharge analysis (flow routing) of the catchment. The water quality parameters (pH, temperature, electric conductivity, dissolved oxygen DO, total dissolved solids TDS, chlorides, ammonium, nitrates) were analyzed by using Hydrolab. Quality assurance (QA) and quality control (QC) procedures were strictly followed throughout the field work and data analysis. Different procedures were employed to evaluate the analytical data and to check for possible transcription or dilution errors, changes during analysis, or unusual or unlikely values. The results obtained are compared with interim national water quality standards for Malaysia indicates that water quality of area is highly degraded. It is concluded that Bestri Jaya ex-mining catchment has a high pollution potential due to mining activities and River Ayer Hitam, recipient of catchment water, is a highly polluted river. PMID:22761549

  14. Developing a multi-pollutant conceptual framework for the selection and targeting of interventions in water industry catchment management schemes.

    Science.gov (United States)

    Bloodworth, J W; Holman, I P; Burgess, P J; Gillman, S; Frogbrook, Z; Brown, P

    2015-09-15

    In recent years water companies have started to adopt catchment management to reduce diffuse pollution in drinking water supply areas. The heterogeneity of catchments and the range of pollutants that must be removed to meet the EU Drinking Water Directive (98/83/EC) limits make it difficult to prioritise areas of a catchment for intervention. Thus conceptual frameworks are required that can disaggregate the components of pollutant risk and help water companies make decisions about where to target interventions in their catchments to maximum effect. This paper demonstrates the concept of generalising pollutants in the same framework by reviewing key pollutant processes within a source-mobilisation-delivery context. From this, criteria are developed (with input from water industry professionals involved in catchment management) which highlights the need for a new water industry specific conceptual framework. The new CaRPoW (Catchment Risk to Potable Water) framework uses the Source-Mobilisation-Delivery concept as modular components of risk that work at two scales, source and mobilisation at the field scale and delivery at the catchment scale. Disaggregating pollutant processes permits the main components of risk to be ascertained so that appropriate interventions can be selected. The generic structure also allows for the outputs from different pollutants to be compared so that potential multiple benefits can be identified. CaRPow provides a transferable framework that can be used by water companies to cost-effectively target interventions under current conditions or under scenarios of land use or climate change.

  15. Lake-catchment systems and sediment information in Baikal district (Siberia and Mongolia)

    Institute of Scientific and Technical Information of China (English)

    KASHIWAYA Kenji

    2011-01-01

    Sediment information is closely related to a lake-catchment system. Lake Baikal and Lake Khuvsgul in the Baikal depression have shown different sedimentary trends during the past 800 ka; the sediment discharge (sedimentation rate) in Baikal basically followed the global climatic change, whereas that in Khuvsgul did not always do so. An elementary mathematical model is used to explain the difference, considering changes in the catchment area and water level. Numerical calculations based on the model suggest that sedimentary conditions are closely related to changes in the water level and erosion area, which probably had a signiifcant inlfuence on Lake Khuvsgul and little inlfuence on Lake Baikal.

  16. Mountaintop Removal Mining and Catchment Hydrology

    Directory of Open Access Journals (Sweden)

    Andrew J. Miller

    2014-03-01

    Full Text Available Mountaintop mining and valley fill (MTM/VF coal extraction, practiced in the Central Appalachian region, represents a dramatic landscape-scale disturbance. MTM operations remove as much as 300 m of rock, soil, and vegetation from ridge tops to access deep coal seams and much of this material is placed in adjacent headwater streams altering landcover, drainage network, and topography. In spite of its scale, extent, and potential for continued use, the effects MTM/VF on catchment hydrology is poorly understood. Previous reviews focus on water quality and ecosystem health impacts, but little is known about how MTM/VF affects hydrology, particularly the movement and storage of water, hence the hydrologic processes that ultimately control flood generation, water chemistry, and biology. This paper aggregates the existing knowledge about the hydrologic impacts of MTM/VF to identify areas where further scientific investigation is needed. While contemporary surface mining generally increases peak and total runoff, the limited MTM/VF studies reveal significant variability in hydrologic response. Significant knowledge gaps relate to limited understanding of hydrologic processes in these systems. Until the hydrologic impact of this practice is better understood, efforts to reduce water quantity and quality problems and ecosystem degradation will be difficult to achieve.

  17. Sediment transfer in coastal catchments exposed to typhoons: lessons learnt from catchments contaminated with Fukushima radioactive fallout

    Science.gov (United States)

    Evrard, Olivier; Laceby, J. Patrick; Onda, Yuichi; Lefèvre, Irène

    2016-04-01

    Several coastal catchments located in Northeastern Japan received significant radioactive fallout following the Fukushima nuclear accident in March 2011, with initial 137Cs activities exceeding 100 kBq m-2. Although radiocesium poses a considerable health risk for local populations, it also provides a relatively straightforward tracer to investigate sediment transfers in catchments exposed to spring floods and heavy typhoons in late summer and early fall. This study focused on two catchments (the Niida and Mano Rivers) covering a surface area of 450 km² that drain the main radioactive plume. A database of radiocesium activities measured in potential source samples (n=260) was used to model radiocesium dilution in 342 sediment deposit samples collected at 38 locations during 9 different sampling campaigns conducted every 6 months from Nov. 2011 to Nov. 2015. The dilution of the initial radiocesium contamination in sediment was individually calculated for each of the 342 samples using a distribution model. Results show that the proportion of heavily contaminated sediment increased from 27% to 39% after the occurrence of typhoons in 2013 (with rainfall amount exceeding 100 mm in 48 hours) and from 29% to 45% after the 2015 spring floods, illustrating the occurrence of soil erosion and resuspension of contaminated material stored in the river channel. In contrast, the occurrence of a very strong typhoon in September 2015 (up to 450 mm in 48h) led to the dilution and the flush of the contamination to the Pacific Ocean, with the proportion of heavily contaminated material decreasing from 45 to 21%. This case study in catchments impacted by the Fukushima accident illustrates their high reactivity to both human activities and rainfall. These results will improve our understanding of sediment transfers in similar coastal mountainous environments frequently exposed to heavy rainfall.

  18. Projected changes in soil organic carbon stocks upon adoption of recommended soil and water conservation practices in the upper Tana river catchment, Kenya

    NARCIS (Netherlands)

    Batjes, N.H.

    2014-01-01

    Large areas in the Upper Tana river catchment, Kenya, have been over-exploited, resulting in soil erosion, nutrient depletion and loss of soil organic matter (SOM). This study focuses on sections of the catchment earmarked as being most promising for implementing Green Water Credits, an incentive

  19. The runoff declining process and water quality in songhuajiang river catchment, China under global climatic change

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Xingmin; Gao, Peng; Wang, Fei [Northwest A and F University, Yangling (China); Institute of Soil and Water Conservation, Chinese Academy of Sciences (CAS), Yangling (China); Li, Ying [Northwest A and F University, Yangling (China); Shao, Hongbo [The CAS/Shandong Provincial Key Laboratory of Coastal Environmental Processes, Yantai Institute of Costal Zone Research, Chinese Academy of Sciences (CAS), Yantai (China); Institute for Life Sciences, Qingdao University of Science and Technology (QUST), Qingdao (China)

    2012-04-15

    The runoff in Songhuajiang River catchment has experienced a decreasing trend during the second half of the 20th century. Serially complete daily rainfall data of 42 rainfall stations from 1959 to 2002 and daily runoff data of five meteorological stations from 1953 to 2005 were obtained. The Mann-Kendall trend test and the sequential version of Mann-Kendall test were employed in this study to test the monthly and annual trends for both rainfall and runoff, to determine the start point of abrupt runoff declining, and to identify the main driving factors of runoff decline. The results showed an insignificant increasing trend in rainfall but a significant decreasing trend in runoff in the catchment. For the five meteorological stations, abrupt runoff decline occurred during 1957-1963 and the middle 1990s. Through Mann-Kendall comparisons for the area-rainfall and runoff for the two decreasing periods, human activity, rather than climatic change, is identified as the main driving factor of runoff decline. Analysis of land use/cover shows that farmland is most related with runoff decline among all the land use/cover change in Nenjiang catchment. From 1986 to 1995, the area of farmland increased rapidly from 6.99 to 7.61 million hm{sup 2}. Hydraulic engineering has a significant influence on the runoff decline in the second Songhuajiang catchment. Many large-scale reservoirs and hydropower stations have been built in the upstream of the Second Songhuajiang and lead to the runoff decline. Nenjiang and the Second Songhuajiang are the two sources of mainstream of Songhuajiang. Decreased runoff in these two sub-catchments then results in runoff decrease in mainstream of Songhuajiang catchment. It is, therefore, concluded that high percent agricultural land and hydraulic engineering are the most probable driving factors of runoff decline in Songhuajiang River catchment, China. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. A methodology to determine pesticides pollution sources in water catchments: study case (Belgium).

    Science.gov (United States)

    Limbourg, Q; Noel, S; Huyghebaert, B; Capette, L; Hallet, V

    2009-01-01

    In the Walloon Region (Belgium), a Committee of Investigation was created in 2007 to investigate and determine the potential pesticides pollution sources in drinkable water catchments. This Committee, constituted by a multidisciplinary team of experts i.e agronomists, soil scientists, phyto-chemists, hydrogeologists, is coordinated by the Walloon Agricultural Research Centre (CRA-W) and funded by the Société Publique de Gestion des Eaux (SPGE). The diagnosis method is inspired of the AQUAPLAINE method (Arvalis, France), and is composed of four steps: 1/preparing the diagnosis using existing data, 2/diagnosis using data bank completed by field observations, 3/meeting and discussion with the pesticide users, 4/final diagnosis and remediation proposal. In a rural district of Walloon Region, a water producer who possesses two catchments ("Les marroniers" (P1) and "Puits N2" (P2)) has problems with pesticides. The pollution started in 1998 with atrazine and bromacile detected in the two catchments. In 2004, 2,6-dichlorobenzamide, metabolite of dichlobenil, was also detected in the catchments. At present, all these pesticides are still found in the catchment P1 and only the 2,6 dichlorobenzamide is found in the other catchment. These active ingredients are not used in agriculture expect atrazine. Indeed, the main user of these products is the public sector. An investigation was realised to locate the main sites which are treated with these pesticides in this commune. The conclusion of this study is that the local authority used dichlobenil, bromacile and atrazine to weed the public areas. In more, the filling and the cleaning areas of sprayer, used for the treatment, are located near the catchments.

  1. Monitoring of a mixed land use catchment for pollutant source characterisation.

    Science.gov (United States)

    Liu, An; Carroll, Steven; Dawes, Les; Goonetilleke, Ashantha

    2017-07-01

    Protection of surface water quality is a key driver in catchment management, particularly for areas undergoing land use change. Changing land use can result in the input of a range of pollutants to surface waters, resulting in water quality impairment, leading to eutrophication and the appearance of algae blooms. This study investigated a mixed land use coastal catchment by undertaking extensive field sampling and data analysis for pollutant source characterisation. The objective was to contribute to a greater understanding of pollutant inputs to surface water resources and for effective catchment management. Based on data analysis results, a diversity of pollutant sources was noted, including both natural areas and areas subject to anthropogenic activities such as agriculture and urban developments, with agricultural areas being comparatively more significant in exporting nutrients. Additionally, pollutant inputs into estuarine and freshwater areas were found to have specific characteristics influenced by land use. The pollutant inputs from these sources were found to be significantly affected by seasonal factors, with the dominant pollutant sources differing between the wet and dry seasons. This underlines the importance of taking seasonal factors into account in the development of effective catchment management strategies. Based on the study outcomes, a critical point monitoring program was developed with a focus on preventing algae blooms. This will allow the development of a decentralised catchment management strategy where resource-efficient monitoring of critical pollutant parameters at key locations can be undertaken for minimising the risk from algae blooms, rather than implementing a whole of catchment and resource-demanding large-scale monitoring program.

  2. Understanding Pesticide Behaviour At The Catchment Scale

    Science.gov (United States)

    Kannan, N.; White, S. M.; Worrall, F.; Pendlington, D.; Groves, S.

    Pesticides in stream flow at the outlet of a 142ha catchment in Eastern England (Col- worth, Bedfordshire), have been monitored since October 1999. About 50% of the total catchment is directly controlled within one farm and a rotation of wheat, oil seed rape, grass, linseed, beans and peas is grown. The data from this catchment are being used to investigate the performance of the USDA SWAT contaminant transport pack- age at the catchment scale. Three years of stream flow and climate data are available with a useful set of pesticide application and detection data. Following calibration and validation of the hydrology of the catchment, pesticide modelling was carried out for tebuconazole, terbutryn, and terbuthylazine. This paper reports on the results of a sen- sitivity analysis of the model, and the final calibrated pesticide component. Analysis of the results obtained show that the timing and decay of predicted pesticide concen- trations are correct. It is therefore recommended that SWAT can be used as a tool to understand pesticide behaviour at the catchment scale.

  3. Topic: Catchment system dynamics: Processes and feedbacks

    Science.gov (United States)

    Keesstra, Saskia

    2015-04-01

    In this meeting we can talk about my main expertise: the focus of my research ocus revolves around understanding catchment system dynamics in a holistic way by incorporating both processes on hillslopes as well as in the river channel. Process knowledge enables explanation of the impact of natural and human drivers on the catchment systems and which consequences these drivers have for water and sediment connectivity. Improved understanding of the catchment sediment and water dynamics will empower sustainable land and river management and mitigate soil threats like erosion and off-side water and sediment accumulation with the help of nature's forces. To be able to understand the system dynamics of a catchment, you need to study the catchment system in a holistic way. In many studies only the hillslopes or even plots are studied; or only the channel. However, these systems are connected and should be evaluated together. When studying a catchment system any intervention to the system will create both on- as well as off sites effects, which should especially be taken into account when transferring science into policy regulations or management decisions.

  4. A new generic approach for estimating the concentrations of down-the-drain chemicals at catchment and national scale

    Energy Technology Data Exchange (ETDEWEB)

    Keller, V.D.J. [Centre for Ecology and Hydrology, Hydrological Risks and Resources, Maclean Building, Crowmarsh Gifford, Wallingford OX10 8BB (United Kingdom)]. E-mail: vke@ceh.ac.uk; Rees, H.G. [Centre for Ecology and Hydrology, Hydrological Risks and Resources, Maclean Building, Crowmarsh Gifford, Wallingford OX10 8BB (United Kingdom); Fox, K.K. [University of Lancaster (United Kingdom); Whelan, M.J. [Unilever Safety and Environmental Assurance Centre, Colworth (United Kingdom)

    2007-07-15

    A new generic approach for estimating chemical concentrations in rivers at catchment and national scales is presented. Domestic chemical loads in waste water are estimated using gridded population data. River flows are estimated by combining predicted runoff with topographically derived flow direction. Regional scale exposure is characterised by two summary statistics: PEC{sub works}, the average concentration immediately downstream of emission points, and, PEC{sub area}, the catchment-average chemical concentration. The method was applied to boron at national (England and Wales) and catchment (Aire-Calder) scales. Predicted concentrations were within 50% of measured mean values in the Aire-Calder catchment and in agreement with results from the GREAT-ER model. The concentration grids generated provide a picture of the spatial distribution of expected chemical concentrations at various scales, and can be used to identify areas of potentially high risk. - A new grid-based approach to predict spatially-referenced freshwater concentrations of domestic chemicals.

  5. AN APPROACH TO THE MODEL USE FOR MEASURING SUSPENDED SEDIMENT YIELD IN UNGAUGED CATCHMENTS

    Directory of Open Access Journals (Sweden)

    Sokchhay Heng

    2013-01-01

    Full Text Available Different types of water resources studies require the information of Suspended Sediment Yield (SSY in different time resolutions. In ungauged watersheds where hydrometeorogical time series are not available, the mean annual SSY (SSYa is solely predictable and catchment area is traditionally used as the predictor because it is the most important variable and generally determined during project planning. Firstly, this research tried to advance the traditional SSYa model by additionally associating global topographic data. Based on the jack-knife procedure, the modified method considering catchment area with slope greater than 15% was evaluated in 17 gauged catchments in the Lower Mekong Basin and the overall predictive accuracy was improved about 66% in term of mean absolute percentage error. Secondly, the predicted SSYa in each modeled catchment was monthly distributed using Unit mean annual Sedimentograph (USGa. The double-average USGa superior to the single-average one provides overall better quality results than the regionalized USGa dependent upon the spatial proximity approach. The model performance measured by Nash-Sutcliffe Efficiency (NSE is about 0.66 in median value and satisfactory results (NSE >0.50 are obtained in 11 catchments. Lastly, the validated regional model was regarded as a potential and feasible tool in solving sediment-ungauged issues in the basin.

  6. Winter streamflow analysis in frozen, alpine catchments to quantify groundwater contribution and properties

    Science.gov (United States)

    Stoelzle, Michael; Weiler, Markus

    2016-04-01

    Alpine catchments are often considered as quickly responding systems where streamflow contributions from subsurface storages (groundwater) are mostly negligible due to the steep topography, low permeable bedrock and the absence of well-developed soils. Many studies in high altitude catchments have hence focused on water stored in snowpack and glaciers or on rainfall-runoff processes as the dominant streamflow contributions. Interestingly less effort has been devoted to winter streamflow analysis when melt- or rainfall-driven contributions are switched off due to the frozen state of the catchment. Considering projected changes in the alpine cryosphere (e.g. snow, glacier, permafrost) quantification of groundwater storage and contribution to streamflow is crucial to assess the social and ecological implications for downstream areas (e.g. water temperature, drought propagation). In this study we hypothesize that groundwater is the main streamflow contribution during winter and thus being responsible for the perennial regime of many alpine catchments. The hypothesis is investigated with well-known methods based on recession and breakpoint analysis of the streamflow regimes and temperature data to determine frozen periods. Analyzing nine catchments in Switzerland with mean elevation between 1000 and 2400 m asl, we found that above a mean elevation of 1800 m asl winter recessions are sufficient long and persistent enough to quantify groundwater contribution to streamflow and to characterize the properties of subsurface storage. The results show that groundwater in alpine catchment is the dominant streamflow contribution for nearly half a year and accountable for several hundred millimeter of annual streamflow. In sub-alpine catchments, driven by a mix of snowmelt and rainfall, a clear quantification of groundwater contributions is rather challenging due to discontinuous frozen periods in winter. We found that the inter-annual variability of different streamflow

  7. High resolution modeling of a small urban catchment

    Science.gov (United States)

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

    2016-04-01

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

  8. Linking the field to the stream: soil erosion and sediment yield in a rural catchment, NW Spain

    Science.gov (United States)

    Rodriguez-Blanco, M. L.; Taboada-Castro, M. M.; Palleiro-Suarez, L.; Taboada-Castro, M. T.

    2009-04-01

    Quantifying the linkages between field erosion, fluvial response and catchment sediment yield remains problematic, among other reasons, because of the re-deposition of eroded sediment within the catchment, which is controlled by the spatial organization of the land use and the connectivity between sediment sources and the stream network. This paper presents the results of an integrated study that considered the relationship between erosion and stream sediment yield in an agroforestry catchment (16 km2) in NW Spain. The geology consists of basic metamorphic schist. The relieve of the area is steeper, the mean slope is approximately 19%. Main soil types are classified as Umbrisol and Cambisol. Soils are acidic and rich in organic matter. The soil texture is silt and silt-loam. Land cover consists of a mixture of forest (65%) and agricultural fields (mainly grassland, pasture and maize). The study combined measurements of soil erosion by concentrate flow and sediment deposition at field scale with sediment yield measured at the catchment outlet. The hydrological data and water samples were obtained at the catchment outlet. Stream water level was monitored continuously and converted to discharge using a rating curve. The sampling for suspended sediments was supplemented by an automatic sampler. Suspended sediment load was calculated from the suspended sediment concentrations and discharge data. Eroded volume was calculated from cross-sections (measured at specific points, where the section changed abruptly) and length of the channel segments. The total sediment delivered to stream was determined as the difference between all erosion features (rills and gullies) and the sediment volumes that were deposited on the fields. The results showed that in the catchment during the period winter 2007/08 soil erosion by concentrate flow, i.e. rills and ephemeral gullies, occurred on unprotected crop field. Erosion by concentrate flow was highly discontinuous within the catchment

  9. Impact of bushfire and climate variability on streamflow from forested catchments in southeast Australia

    Directory of Open Access Journals (Sweden)

    Y. Zhou

    2013-04-01

    Full Text Available Most of the surface water for natural environmental and human water uses in southeast Australia is sourced from forested catchments located in the higher rainfall areas. Water yield of these catchments is mainly affected by climatic conditions, but it is also greatly affected by vegetation cover change. Bushfires are a major natural disturbance in forested catchments and potentially modify the water yield of the catchments through changes to evapotranspiration (ET, interception and soil moisture storage. This paper quantifies the impacts of bushfire and climate variability on streamflow from three southeast Australian catchments where Ash Wednesday bushfires occurred in February 1983. The hydrological models used here include AWRA-L, Xinanjiang and GR4J. The three models are first calibrated against streamflow data from the pre-bushfire period and they are used to simulate runoff for the post-bushfire period with the calibrated parameters. The difference between the observed and model simulated runoff for the post-bushfire period provides an estimate of the impact of bushfire on streamflow. The hydrological modelling results for the three catchments indicate that there is a substantial increase in streamflow in the first 15 yr after the 1983 bushfires. The increase in streamflow is attributed to initial decreases in ET and interception resulting from the fires, followed by logging activity. After 15 yr, streamflow dynamics are more heavily influenced by climate effects, although some impact from fire and logging regeneration may still occur. It is shown that hydrological models provide reasonable consistent estimates of forest disturbance and climate impacts on streamflow for the three catchments. The results might be used by forest managers to understand the relationship between forest disturbance and climate variability impacts on water yield in the context of climate change.

  10. Rainwater Harvesting in South India: Understanding Water Storage and Release Dynamics at Tank and Catchment Scales

    Science.gov (United States)

    Basu, N. B.; Van Meter, K. J.; Mclaughlin, D. L.; Steiff, M.

    2015-12-01

    Rainwater harvesting, the small-scale collection and storage of runoff for irrigated agriculture, is recognized as a sustainable strategy for ensuring food security, especially in monsoonal landscapes in the developing world. In south India, these strategies have been used for millennia to mitigate problems of water scarcity. However, in the past 100 years many traditional rainwater harvesting systems have fallen into disrepair due to increasing dependence on groundwater. With elevated declines in groundwater resources, there is increased effort at the state and national levels to revive older systems. Critical to the success of such efforts is an improved understanding of how these ancient water-provisioning systems function in contemporary landscapes with extensive groundwater pumping and shifted climatic regimes. Knowledge is especially lacking regarding the water-exchange dynamics of these rainwater harvesting "tanks" at tank and catchment scales, and how these exchanges regulate tank performance and catchment water balances. Here, we use fine-scale water level variations to quantify daily fluxes of groundwater, evapotranspiration, and sluice outflows in four tanks over the 2013 northeast monsoon season in a tank cascade that covers a catchment area of 28.2 km2. Our results indicate a distinct spatial pattern in groundwater-exchange dynamics, with the frequency and magnitude of groundwater inflow events (as opposed to outflow) increasing down the cascade of tanks. The presence of tanks in the landscape dramatically alters the catchment water balance, with catchment-scale runoff:rainfall ratios decreasing from 0.29 without tanks to 0.04 - 0.09 with tanks. Recharge:rainfall ratios increase in the presence of tanks, from ~0.17 in catchments without tanks to ~ 0.26 in catchments with tanks. Finally, our results demonstrate how more efficient management of sluice outflows can lead to the tanks meeting a higher fraction of crop water requirements.

  11. How does landscape structure influence catchment transit time across different geomorphic provinces?

    Science.gov (United States)

    Tetzlaff, D.; Seibert, J.; McGuire, K.J.; Laudon, H.; Burns, Douglas A.; Dunn, S.M.; Soulsby, C.

    2009-01-01

    Despite an increasing number of empirical investigations of catchment transit times (TTs), virtually all are based on individual catchments and there are few attempts to synthesize understanding across different geographical regions. Uniquely, this paper examines data from 55 catchments in five geomorphic provinces in northern temperate regions (Scotland, United States of America and Sweden). The objective is to understand how the role of catchment topography as a control on the TTs differs in contrasting geographical settings. Catchment inverse transit time proxies (ITTPs) were inferred by a simple metric of isotopic tracer damping, using the ratio of standard deviation of ??18O in streamwater to the standard deviation of ??18O in precipitation. Quantitative landscape analysis was undertaken to characterize the catchments according to hydrologically relevant topographic indices that could be readily determined from a digital terrain model (DTM). The nature of topographic controls on transit times varied markedly in different geomorphic regions. In steeper montane regions, there are stronger gravitational influences on hydraulic gradients and TTs tend to be lower in the steepest catchments. In provinces where terrain is more subdued, direct topographic control weakened; in particular, where flatter areas with less permeable soils give rise to overland flow and lower TTs. The steeper slopes within this flatter terrain appear to have a greater coverage of freely draining soils, which increase sub-surface flow, therefore increasing TTs. Quantitative landscape analysis proved a useful tool for intercatchment comparison. However, the critical influence of sub-surface permeability and connectivity may limit the transferability of predictive tools of hydrological function based on topographic parameters alone. Copyright ?? 2009 John Wiley & Sons, Ltd.

  12. Applying different spatial distribution and modelling concepts in three nested mesoscale catchments of Germany

    Science.gov (United States)

    Bongartz, K.

    Distributed, physically based river basin models are receiving increasing importance in integrated water resources management (IWRM) in Germany and in Europe, especially after the release of the new European Water Framework Directive (WFD). Applications in mesoscale catchments require an appropriate approach to represent the spatial distribution of related catchment properties such as land use, soil physics and topography by utilizing techniques of remote sensing and GIS analyses. The challenge is to delineate scale independent homogeneous modelling entities which, on the one hand may represent the dynamics of the dominant hydrological processes and, on the other hand can be derived from spatially distributed physiographical catchment properties. This scaling problem is tackled in this regional modelling study by applying the concept of hydrological response units (HRUs). In a nested catchment approach three different modelling conceptualisations are used to describe the runoff processes: (i) the topographic stream-segment-based HRU delineation proposed by Leavesley et al. [Precipitation-Runoff-Modelling-System, User’s Manual, Water Resource Investigations Report 83-4238, US Geological Survey, 1983]; (ii) the process based physiographic HRU-concept introduced by Flügel [Hydrol. Process. 9 (1995) 423] and (iii) an advanced HRU-concept adapted from (ii), which included the topographic topology of HRU-areas and the river network developed by Staudenraush [Eco Regio 8 (2000) 121]. The influence of different boundary conditions associated with changing the landuse classes, the temporal data resolution and the landuse scenarios were investigated. The mesoscale catchment of the river Ilm ( A∼895 km 2) in Thuringia, Germany, and the Precipitation-Runoff-Modelling-System (PRMS) were selected for this study. Simulations show that the physiographic based concept is a reliable method for modelling basin dynamics in catchments up to 200 km 2 whereas in larger catchments

  13. Sediment transfer processes in a debris-flow dominated catchment in the Swiss Alps

    Science.gov (United States)

    McArdell, B. W.; Berger, C.; Schlunegger, F.

    2009-12-01

    The transfer of sediment from steep hillslopes into channels and subsequent mobilization remains a problem with implications for the development of landscapes as well as applications in natural hazards mitigation. The Illgraben catchment in the Swiss Alps is among the most active catchments in Europe, with several 100’000 cubic meters of sediment exported from the catchment (active area debris flows every year, providing an exceptional opportunity to investigate the transfer of sediment from hillslopes to the outlet of the channel at the distal end of the alluvial fan. Thirty-four debris flows or similar torrential flash flood/hyper-concentrated flows have been recorded at the debris flow observation station since the year 2000. Data are available for many flow properties including front velocity (max. 10 m/s) and front flow depth (max. 3.25 m) as well as estimates for debris flow volume (max. 85,000 cubic meters). Flow bulk density data are also available from a large force plate installation for most flows since 2004, permitting estimation of sediment export from the catchment by debris flows. The channel morphology is strongly affected by these events, and debris flows can increase their volume considerably by entraining material from the channel bed. Aerial photography of the initiation area and upper catchment (fall 2007, early summer and fall 2008; fall 2009 is planned) and photogrammetric analyses allow detection of areas of land surface elevation change (deposition or erosion). Strong hillslope channel coupling is expected, with sediment delivery to the steep torrent channels by rockfall and other mass-movement processes. The upper catchment is generally quite active, yet the main sediment source of debris flows varies from event to event In some cases it was possible to identify the movement of small landslides into torrent channels and the subsequent removal by debris flows. In other cases no landslide activity was obvious and the sediment for the

  14. Upscaling spatially heterogeneous parameterisations of soil compaction to investigate catchment scale flood risk.

    Science.gov (United States)

    Coates, Victoria; Pattison, Ian

    2016-04-01

    Upscaling land management signals observed at the point scale to the regional scale is challenging for three reasons. Individual catchments are unique and at the point scale land management signals are spatially and temporally variable, depending on topography, soil characteristics and on the individual characteristics of a rainfall event. However at larger scales land management effects diffuse and climatic or human induced signals have a larger impact. This does not mean that there is no influence on river flows, just that the effect is not discernible. Land management practices in different areas of the catchment vary spatially and temporally and their influence on the flood hydrograph will be different at different points within the catchment. Once the water enters the river, the land management effects are disturbed further by hydrodynamic and geomorphological dispersion. Pastoral agriculture is the dominant rural land cover in the UK (40% is classified as improved/ semi-natural grassland - Land Cover Map 2007). The intensification of agriculture has resulted in greater levels of soil compaction associated with higher stocking densities in fields. Natural flood management is the alteration, restoration or use of landscape features to reduce flood risk. Soil compaction has been shown to change the partitioning of rainfall into runoff. However the link between locally observed hydrological changes and catchment scale flood risk has not yet been proven. This paper presents the results of a hydrological modelling study on the impact of soil compaction on downstream flood risk. Field experiments have been conducted in multiple fields in the River Skell catchment, in Yorkshire, UK (area of 120km2) to determine soil characteristics and compaction levels under different types of land-use. We use this data to parameterise and validate the Distributed Physically-based Connectivity of Runoff model. A number of compaction scenarios have been tested that represent

  15. Rainwater catchment system design using simulated future climate data

    Science.gov (United States)

    Wallace, Corey D.; Bailey, Ryan T.; Arabi, Mazdak

    2015-10-01

    Rainwater harvesting techniques are used worldwide to augment potable water supply, provide water for small-scale irrigation practices, increase rainwater-use efficiency for sustained crop growth in arid and semi-arid regions, decrease urban stormwater flow volumes, and in general to relieve dependency on urban water resources cycles. A number of methods have been established in recent years to estimate reliability of rainwater catchment systems (RWCS) and thereby properly size the components (roof catchment area, storage tank size) of the system for a given climatic region. These methods typically use historical or stochastically-generated rainfall patterns to quantify system performance and optimally size the system, with the latter accounting for possible rainfall scenarios based on statistical relationships of historical rainfall patterns. To design RWCS systems that can sustainably meet water demand under future climate conditions, this paper introduces a method that employs climatic data from general circulation models (GCMs) to develop a suite of catchment area vs. storage size design curves that capture uncertainty in future climate scenarios. Monthly rainfall data for the 2010-2050 time period is statistically downscaled to daily values using a Markov chain algorithm, with results used only from GCMs that yield rainfall patterns that are statistically consistent with historical rainfall patterns. The process is demonstrated through application to two climatic regions of the Federated States of Micronesia (FSM) in the western Pacific, wherein the majority of the population relies on rainwater harvesting for potable water supply. Through the use of design curves, communities can provide household RWCS that achieve a certain degree of storage reliability. The method described herein can be applied generally to any geographic region. It can be used to first, assess the future performance of existing household systems; and second, to design or modify systems

  16. In Lieu of the Paired-Catchment Approach - Hydrologic Model Change Detection at the Catchment Scale

    Science.gov (United States)

    Zegre, N. P.

    2009-05-01

    Knowledge of the effects of forest management on hydrology primarily comes from paired-catchment studies conducted world-wide. While this approach has been useful for discerning changes in small experimental catchments and has contributed fundamental knowledge of the effects of forest and natural resources management on hydrology, results from experimental catchment studies exhibit temporal variability, have limited spatial inference, and lack insight into internal catchment processes. To address these limitations, traditional field experiments can be supplemented with numerical models to isolate the effects of disturbance on catchment behavior. Outlined in this study is an alternative method of change detection for daily time-series streamflow that integrates hydrologic modeling and statistical change detection methods used to discern the effects of contemporary forest management on the hydrology of western Oregon Cascades headwater catchments. In this study, a simple rainfall-runoff model was used to generate virtual reference catchments using attributes that reflect streamflow conditions absent of forest disturbance. Streamflow was simulated under three levels of model uncertainty using GLUE and were used to construct generalized least squares regression models to discern changes in hydrologic behavior. By considering processes within a single experimental catchment rather than the two spatially explicit catchments used in traditional paired experiments, it was possible to reduce unexplained variation and increase the likelihood of correctly detecting hydrologic effects following forest harvesting. In order to evaluate the stability of the hydrologic and statistical models and catchment behavior over time, the change detection method was applied to a contemporary reference catchment. By applying the change detection model to reference catchments, it was possible to eliminate unexpected variation as a cause for detected changes in observed hydrology. Further, it

  17. Modeling approaches to detect land-use changes: Urbanization analyzed on a set of 43 US catchments

    Science.gov (United States)

    Salavati, Bahar; Oudin, Ludovic; Furusho-Percot, Carina; Ribstein, Pierre

    2016-07-01

    Paired catchment approach probably provides the most robust method to detect the effects of land-use change on catchments' flow characteristics. This approach is limited by the availability of two neighbor catchments with and without land-use change under similar climate conditions. This paper uses a hydrological model to detect the hydrological change caused by urbanization. This study describes (1) use a statistical method to evaluate change detection relative to variation of land use change, (2) simulation of non-urban condition for the urban catchment with an alternative approach, to this aim stream flow series of urban catchments have been reconstructed from the period that urbanization had not taken place yet, and (3) the model validation with observed data. This paper intends to compare the flow changes detected by two different approaches: a regional statistical approach (the paired-catchment approach) and a conceptual modeling approach (the residual approach) on the particular case of urbanized catchments. To investigate the sensitivity of the results to the settings of both approaches, the comparison is made on a relatively large number of 43 catchments located in the United States, with relatively large gradients in terms of geomorphology and hydroclimatic characteristics. Results show that the two approaches are generally in relative good agreement in terms of detection and quantification of changes for the three flow characteristics analyzed (mean annual flow, high and low flow characteristics). Besides, it is found that the impact of urbanization on the catchment's hydrologic response is difficult to generalize: the proportion of nonsignificant trends, significantly increasing decreasing trends are on the same order of magnitude, even if an increase in urban areas generally has a greater impact on mean flows and high flows than on low flows.

  18. The artifcial catchment Chicken Creek as a tool to study initial ecosystem development

    Science.gov (United States)

    Schaaf, W.; Elmer, M.; Fischer, A.; Gerwin, W.; Nenov, R.

    2011-12-01

    The artificial catchment Chicken Creek was constructed in 2005 to study the increasingly complex interactions of processes and structures during initial development of ecosystems. The 6ha area serves as the central research site for the Transregional Collaborative Research Center 38. Both internal and external factors could be identified as driving forces for the formation of structures and patterns in the artificial catchment during the first five years of development. Initial structures formed by the construction process (e.g. catchment morphology, subsurface structures like clay dams and dumping cones, caterpillar tracks at the surface) and initial substrate characteristics (e.g. texture, geochemistry) were decisive both for the distribution and flow of precipitation water and for vegetation succession. External factors like episodic events (e.g. heavy thunderstorms) triggered erosion and dissection during this initial phase, promoted by the low vegetation cover and the unconsolidated sandy substrate. These processes resulted in transport and redistribution of water and sediment within the catchment, mainly along the main slope, and the formation of new structural elements like gullies and channels, a sedimentation fan above and sediments within the pond. As a result, we observed an overall differentiation of the site, e.g. with respect to water availability and texture redistribution, into areas with abrasion or accumulation processes dominating and areas with stable surfaces. During further development, both external factors and processes within the catchment continued to influence the site. For example, beside the initial soil seed bank, the surrounding environment of the catchment clearly affected species invasion. The dissection and stability of surfaces may be an important factor for the establishment of plants and habitats as well as for the formation of vegetation patterns and biological soil crusts. The transformation of the initial geo-system into

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

    Directory of Open Access Journals (Sweden)

    J.-C. Huang

    2010-12-01

    Full Text Available Agricultural activity is the dominant factor affecting water quality and nitrate export, which causes eutrophication and episodic acidification in downstream water bodies (e.g., reservoirs, lakes, and coastal zones. However, in subtropical mountainous areas such environmental impact due to the land use change was rarely documented. In this study, we investigated 16 sub-catchments during 2007 and 2008 in the Chi-Chia-Wan catchment where is the sole habitat for the endemic species, Formosan landlocked salmon (Oncorhynchus masou formosanus.

    The results revealed that the NO3-N concentration in pristine catchments varied from 0.144 to 0.151 mg/L without significant seasonal variation. This concentration was comparable with other forestry catchments around the world. However, the annual nitrate export was around 375.3–677.1 kg/km2/yr, much higher than other catchments due to the greater amount of rainfall. This is an important baseline for comparisons with other climate areas. As for the impact of agricultural activities, the catchments with some human disturbance, ~5.2% of the catchment area, might yield 5947.2 kg N/km2/yr – over 10-times higher than that of pristine catchment. Such high export caused by such a low level of disturbance might indicate that subtropical mountainous area is highly sensitive to agricultural activities. As for the land-use effect on nitrate yield, the forestry land might yield 488.5 ± 325.1 kg/km2/yr and the vegetable farm could yield 298 465.4 ± 3347.2 kg/km2/yr – 1000-times greater than the forestry. The estimated nitrate yields for land use classes were a crucial basis and useful for the land manager to assess the possible impacts (e.g., non-point source pollution evaluation and the recovery of land expropriation.

  20. Feasibility and Effectiveness of a Multi-Element Psychosocial Intervention for First-Episode Psychosis: Results From the Cluster-Randomized Controlled GET UP PIANO Trial in a Catchment Area of 10 Million Inhabitants.

    Science.gov (United States)

    Ruggeri, Mirella; Bonetto, Chiara; Lasalvia, Antonio; Fioritti, Angelo; de Girolamo, Giovanni; Santonastaso, Paolo; Pileggi, Francesca; Neri, Giovanni; Ghigi, Daniela; Giubilini, Franco; Miceli, Maurizio; Scarone, Silvio; Cocchi, Angelo; Torresani, Stefano; Faravelli, Carlo; Cremonese, Carla; Scocco, Paolo; Leuci, Emanuela; Mazzi, Fausto; Pratelli, Michela; Bellini, Francesca; Tosato, Sarah; De Santi, Katia; Bissoli, Sarah; Poli, Sara; Ira, Elisa; Zoppei, Silvia; Rucci, Paola; Bislenghi, Laura; Patelli, Giovanni; Cristofalo, Doriana; Meneghelli, Anna

    2015-09-01

    Integrated multi-element psychosocial interventions have been suggested to improve the outcomes of first-episode psychosis (FEP) patients, but they have been studied primarily in experimental settings and in nonepidemiologically representative samples. Thus, we performed a cluster-randomized controlled trial, comparing an integrated multi-element psychosocial intervention, comprising cognitive behavioral therapy, family intervention, and case management, with treatment as usual (TAU) for FEP patients in 117 community mental health centers (CMHCs) in a large area of northern Italy (10 million inhabitants). The randomized units (clusters) were the CMHCs, and the units of observation the patients (and, when available, their family members). The primary hypotheses were that add-on multicomponent intervention: (1) results in greater improvements in symptoms, as assessed with positive and negative syndrome scale and (2) reduces in-hospital stay, based on days of hospitalization over the 9-month follow-up. Four hundred and forty-four FEP patients received the intervention or TAU and were assessed at baseline and 9 months. Based on the retention rates of patients (and families) in the experimental arm, multi-element psychosocial interventions can be implemented in routine mental health services. Regarding primary outcomes, patients in the experimental arm showed greater reductions in overall symptom severity, while no difference could be found for days of hospitalization. Among the secondary outcomes, greater improvements were detected in the experimental arm for global functioning, emotional well-being, and subjective burden of delusions. No difference could be found for service disengagement and subjective burden of auditory hallucinations. These findings support feasibility and effectiveness of early interventions for psychosis in generalist mental health services.

  1. Quantification and Genotyping of Human Sapoviruses in the Llobregat River Catchment, Spain▿ †

    Science.gov (United States)

    Sano, Daisuke; Pérez-Sautu, Unai; Guix, Susana; Pintó, Rosa Maria; Miura, Takayuki; Okabe, Satoshi; Bosch, Albert

    2011-01-01

    Human sapoviruses (SaVs) were quantified and characterized in an 18-month survey conducted along the Llobregat river catchment area in Spain. Sample types included freshwater, untreated and treated wastewater, and drinking water. All genogroups were recovered, and a seasonal distribution was observed. This is the first report of SaV quantification and genotyping in the environment outside Japan. PMID:21148702

  2. Quantification and Genotyping of Human Sapoviruses in the Llobregat River Catchment, Spain▿ †

    OpenAIRE

    Sano, Daisuke; Pérez-Sautu, Unai; Guix, Susana; Pintó, Rosa Maria; Miura, Takayuki; Okabe, Satoshi; Bosch, Albert

    2010-01-01

    Human sapoviruses (SaVs) were quantified and characterized in an 18-month survey conducted along the Llobregat river catchment area in Spain. Sample types included freshwater, untreated and treated wastewater, and drinking water. All genogroups were recovered, and a seasonal distribution was observed. This is the first report of SaV quantification and genotyping in the environment outside Japan.

  3. History and prospect of catchment biogeochemistry: a european perspective based on acid rain

    NARCIS (Netherlands)

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

    2004-01-01

    Hydrochemical monitoring of catchments provided a philosophical framework as well as hard data to understand and quantify the linked biological and abiotic processes that explain how atmospheric deposition of S and N changed soils and waters in nonagricultural areas across Europe. Initially, as a to

  4. History and prospect of catchment biogeochemistry: a european perspective based on acid rain

    NARCIS (Netherlands)

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

    2004-01-01

    Hydrochemical monitoring of catchments provided a philosophical framework as well as hard data to understand and quantify the linked biological and abiotic processes that explain how atmospheric deposition of S and N changed soils and waters in nonagricultural areas across Europe. Initially, as a

  5. Situational analysis of the microbial water quality in a peri-urban catchment in South Africa

    CSIR Research Space (South Africa)

    Venter, SN

    1997-01-01

    Full Text Available A situational analysis of a peri-urban catchment experiencing microbial water quality problems was carried out using data collected over two and a half years. The water and land use in the area was determined. The main sources of pollution were...

  6. [Differences in urbanization process of catchments in dongjiang watershed and their effects on landscape pattern].

    Science.gov (United States)

    Ren, Wen-tao; Peng, Shao-lin; Zhou, Ting; Li, Yan

    2008-12-01

    Based on 1991, 1998, and 2006 TM images, the areas of different land use types and the landscape indices of three catchments (catchment a, b, and c, which represented upper, middle, and lower reaches, respectively) in Dongjiang watershed were analyzed, aimed to study the differences in urbanization process along Dongjiang River, and their effects on landscape pattern. The results showed that the degree and speed of urbanization increased from the upper to the lower reach of Dongjiang River. Urbanization had significantly effects on water and vegetation. Urban land area was positively correlated with water body area, and negatively correlated with forest land area. However, to some extent, urbanization stepped into a relatively high degree might benefit forest recovery. The landscape pattern of catchments a and b kept complicating from 1991 to 2006, while that of catchment c was getting complex from 1991 to 1998 and then becoming simple from 1998 to 2006, indicating that with the development of urbanization, landscape pattern presented a "simple-complex-simple" tendency. Understanding the change patterns of the landscape pattern along Dongjiang River would benefit the management and sustainable development of the watershed as a whole.

  7. Development of a hydrological model for simulation of runoff from catchments unbounded by ridge lines

    Science.gov (United States)

    Vema, Vamsikrishna; Sudheer, K. P.; Chaubey, I.

    2017-08-01

    Watershed hydrological models are effective tools for simulating the hydrological processes in the watershed. Although there are a plethora of hydrological models, none of them can be directly applied to make water conservation decisions in irregularly bounded areas that do not confirm to topographically defined ridge lines. This study proposes a novel hydrological model that can be directly applied to any catchment, with or without ridge line boundaries. The model is based on the water balance concept, and a linear function concept to approximate the cross-boundary flow from upstream areas to the administrative catchment under consideration. The developed model is tested in 2 watersheds - Riesel Experimental Watershed and a sub-basin of Cedar Creek Watershed in Texas, USA. Hypothetical administrative catchments that did not confirm to the location of ridge lines were considered for verifying the efficacy of the model for hydrologic simulations. The linear function concept used to account the cross boundary flow was based on the hypothesis that the flow coming from outside the boundary to administrative area was proportional to the flow generated in the boundary grid cell. The model performance was satisfactory with an NSE and r2 of ≥0.80 and a PBIAS of <25 in all the cases. The simulated hydrographs for the administrative catchments of the watersheds were in good agreement with the observed hydrographs, indicating a satisfactory performance of the model in the administratively bounded areas.

  8. Parameterization of a Hydrological Model for a Large, Ungauged Urban Catchment

    Directory of Open Access Journals (Sweden)

    Gerald Krebs

    2016-10-01

    Full Text Available Urbanization leads to the replacement of natural areas by impervious surfaces and affects the catchment hydrological cycle with adverse environmental impacts. Low impact development tools (LID that mimic hydrological processes of natural areas have been developed and applied to mitigate these impacts. Hydrological simulations are one possibility to evaluate the LID performance but the associated small-scale processes require a highly spatially distributed and explicit modeling approach. However, detailed data for model development are often not available for large urban areas, hampering the model parameterization. In this paper we propose a methodology to parameterize a hydrological model to a large, ungauged urban area by maintaining at the same time a detailed surface discretization for direct parameter manipulation for LID simulation and a firm reliance on available data for model conceptualization. Catchment delineation was based on a high-resolution digital elevation model (DEM and model parameterization relied on a novel model regionalization approach. The impact of automated delineation and model regionalization on simulation results was evaluated for three monitored study catchments (5.87–12.59 ha. The simulated runoff peak was most sensitive to accurate catchment discretization and calibration, while both the runoff volume and the fit of the hydrograph were less affected.

  9. Organochlorine pesticide residue levels in soil from the Nyando river catchment, Kenya

    NARCIS (Netherlands)

    Abong'o, D.A.; Wandiga, S.O.; Jumba, I.O.; Brink, van den P.J.; Nazariwo, B.B.; Madadi, V.O.; Wafula, H.; Kylin, H.

    2015-01-01

    Soil samples were collected from six locations representative of the Nyando River catchment area of the Lake Victoria over a period of two years. Sampling was done four times in the year in February, May, September and December 2005 and 2006 in farms where maize, tea, sugar cane, coffee, rice and ve

  10. Storm runoff quality and pollutant loading from commercial, residential, and industrial catchments in the tropic.

    Science.gov (United States)

    Chow, M F; Yusop, Z; Shirazi, S M

    2013-10-01

    Information on the pollution level and the influence of hydrologic regime on the stormwater pollutant loading in tropical urban areas are still scarce. More local data are still required because rainfall and runoff generation processes in tropical environment are very different from the temperate regions. This study investigated the extent of urban runoff pollution in residential, commercial, and industrial catchments in the south of Peninsular Malaysia. Stormwater samples and flow rate data were collected from 51 storm events. Samples were analyzed for total suspended solids, 5-day biochemical oxygen demand, chemical oxygen demand, oil and grease (O&G), nitrate nitrogen (NO3-N), nitrite nitrogen, ammonia nitrogen, soluble reactive phosphorus, total phosphorus (TP), and zinc (Zn). It was found that the event mean concentrations (EMCs) of pollutants varied greatly between storm characteristics and land uses. The results revealed that site EMCs for residential catchment were lower than the published data but higher for the commercial and industrial catchments. All rainfall variables were negatively correlated with EMCs of most pollutants except for antecedent dry days (ADD). This study reinforced the earlier findings on the importance of ADD for causing greater EMC values with exceptions for O&G, NO3-N, TP, and Zn. In contrast, the pollutant loadings are influenced primarily by rainfall depth, mean intensity, and max 5-min intensity in all the three catchments. Overall, ADD is an important variable in multiple linear regression models for predicting the EMC values in the tropical urban catchments.

  11. 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.

  12. Catchment classification: empirical analysis of hydrologic similarity based on catchment function in the eastern USA

    Directory of Open Access Journals (Sweden)

    K. Sawicz

    2011-09-01

    Full Text Available Hydrologic similarity between catchments, derived from similarity in how catchments respond to precipitation input, is the basis for catchment classification, for transferability of information, for generalization of our hydrologic understanding and also for understanding the potential impacts of environmental change. An important question in this context is, how far can widely available hydrologic information (precipitation-temperature-streamflow data and generally available physical descriptors be used to create a first order grouping of hydrologically similar catchments? We utilize a heterogeneous dataset of 280 catchments located in the Eastern US to understand hydrologic similarity in a 6-dimensional signature space across a region with strong environmental gradients. Signatures are defined as hydrologic response characteristics that provide insight into the hydrologic function of catchments. A Bayesian clustering scheme is used to separate the catchments into 9 homogeneous classes, which enable us to interpret hydrologic similarity with respect to similarity in climatic and landscape attributes across this region. We finally derive several hypotheses regarding controls on individual signatures from the analysis performed here.

  13. Catchments as heterogeneous and multi-species reactors: An integral approach for identifying biogeochemical hot-spots at the catchment scale

    Science.gov (United States)

    Weyer, Christina; Peiffer, Stefan; Schulze, Kerstin; Borken, Werner; Lischeid, Gunnar

    2014-11-01

    From a biogeochemical perspective, catchments can be regarded as reactors that transform the input of various substances via precipitation or deposition as they pass through soils and aquifers towards draining streams. Understanding and modeling the variability of solute concentrations in catchment waters require the identification of the prevailing processes, determining their respective contribution to the observed transformation of substances, and the localization of "hot spots", that is, the most reactive areas of catchments. For this study, we applied a non-linear variant of the Principle Component Analysis, the Isometric Feature Mapping (Isomap), to a data set composed of 1686 soil solution, groundwater and stream water samples and 16 variables (Al, Ca, Cl, Fe, K, Mg, Mn, Na, NH4, NO3, SO4, total S, Si, DOC, electric conductivity and pH values) from the Lehstenbach catchment in Germany. The aim was (i) to assess the contribution of the prevailing biogeochemical processes to the variability of solute concentrations in water samples taken from soils, in groundwater and in stream water in a catchment and (ii) to identify hot spots at the catchment scale with respect to 16 solutes along different flow paths. The first three dimensions of the Isomap analysis explained 48%, 30% and 11%, respectively, i.e. 89% of the variance in the data set. Scores of the first three dimensions could be ascribed to three predominating bundles of biogeochemical processes: (i) redox processes, (ii) acid-induced podzolization, and (iii) weathering processes. In general, the upper 1 m topsoil layer could be considered as hot spots along flow paths from upslope soils and in the wetland, although with varying extents for the different prevailing biogeochemical processes. Nearly 67% and 97% of the variance with respect to redox processes and acid induced podzolization could be traced back to hot spots, respectively, representing less than 2% of the total spatial volume of the catchment

  14. Patterns and Pathways of Evolving Catchment Response in a Medium-Sized Mediterranean Catchment on a Millennium Scale

    Science.gov (United States)

    van Beek, L. P. H.; Bierkens, M. F. P.

    2012-04-01

    The meso-scale landscape dynamics model, CALEROS, has been developed to simulate the interactions between climate, soil production and erosion, vegetation and land use on geomorphological to human time scales in Mediterranean environments. Starting from an initial landscape consisting of a DTM, soil distribution and underlying lithology, the landscape is free to develop in response to the imposed climate variability and seismicity. In addition to changes in soil distribution and bedrock lowering, this includes the establishment of vegetation as conditioned by a selection of plant functional types and, optionally, population and land use dynamics as conditioned by land use scenarios specifying technological and dietary constraints for different periods. As such CALEROS is well-suited to investigate the relative impacts of climate, land cover and human activities on the hydrological catchment response and the associated sediment fluxes due to soil erosion and mass movements. Here we use CALEROS to i) investigate the redistribution of water and sediment across the landscape in a medium-sized Mediterranean catchment (Contrada Maddalena; ~14km2, Calabria, Italy) and ii) to establish patterns of co-evolution in soil properties and vegetation under pristine and anthropogenically impacted conditions on a millennium-scale. Using summary statistics to describe the emergent properties and to verify them against observations, we then delineate areas of uniform morphology and describe the various pathways of development. This information allows us to identify elements of consistent hydrological response and the associated transfer of material across different scales. It also provides essential information on essential feedbacks and the resulting convergence or divergence in landscape development under the impact of climatic or seismic events or human intervention. Although the results are evidently conditioned by the physiographic setting of the study area and by the

  15. Improving Distributed Runoff Prediction in Urbanized Catchments with Remote Sensing based Estimates of Impervious Surface Cover

    Science.gov (United States)

    Chormanski, Jaroslaw; Van de Voorde, Tim; De Roeck, Tim; Batelaan, Okke; Canters, Frank

    2008-01-01

    The amount and intensity of runoff on catchment scale are strongly determined by the presence of impervious land-cover types, which are the predominant cover types in urbanized areas. This paper examines the impact of different methods for estimating impervious surface cover on the prediction of peak discharges, as determined by a fully distributed rainfall-runoff model (WetSpa), for the upper part of the Woluwe River catchment in the southeastern part of Brussels. The study shows that detailed information on the spatial distribution of impervious surfaces, as obtained from remotely sensed data, produces substantially different estimates of peak discharges than traditional approaches based on expert judgment of average imperviousness for different types of urban land use. The study also demonstrates that sub-pixel estimation of imperviousness may be a useful alternative for more expensive high-resolution mapping for rainfall-runoff modelling at catchment scale.

  16. East African wetland-catchment data base for sustainable wetland management

    Directory of Open Access Journals (Sweden)

    C. Leemhuis

    2016-10-01

    Full Text Available Wetlands cover an area of approx. 18 Mio ha in the East African countries of Kenya, Rwanda, Uganda and Tanzania, with still a relative small share being used for food production. Current upland agricultural use intensification in these countries due to demographic growth, climate change and globalization effects are leading to an over-exploitation of the resource base, followed by an intensification of agricultural wetland use. We aim on translating, transferring and upscaling knowledge on experimental test-site wetland properties, small-scale hydrological processes, and water related ecosystem services under different types of management from local to national scale. This information gained at the experimental wetland/catchment scale will be embedded as reference data within an East African wetland-catchment data base including catchment physical properties and a regional wetland inventory serving as a base for policy advice and the development of sustainable wetland management strategies.

  17. East African wetland-catchment data base for sustainable wetland management

    Science.gov (United States)

    Leemhuis, Constanze; Amler, Esther; Diekkrüger, Bernd; Gabiri, Geofrey; Näschen, Kristian

    2016-10-01

    Wetlands cover an area of approx. 18 Mio ha in the East African countries of Kenya, Rwanda, Uganda and Tanzania, with still a relative small share being used for food production. Current upland agricultural use intensification in these countries due to demographic growth, climate change and globalization effects are leading to an over-exploitation of the resource base, followed by an intensification of agricultural wetland use. We aim on translating, transferring and upscaling knowledge on experimental test-site wetland properties, small-scale hydrological processes, and water related ecosystem services under different types of management from local to national scale. This information gained at the experimental wetland/catchment scale will be embedded as reference data within an East African wetland-catchment data base including catchment physical properties and a regional wetland inventory serving as a base for policy advice and the development of sustainable wetland management strategies.

  18. Risk-based prioritization of ground water threatening point sources at catchment and regional scales

    DEFF Research Database (Denmark)

    Overheu, Niels Døssing; Tuxen, Nina; Flyvbjerg, John;

    2014-01-01

    framework has been developed to enable a systematic and transparent risk assessment and prioritization of contaminant point sources, considering the local, catchment, or regional scales (Danish EPA, 2011, 2012). The framework has been tested in several catchments in Denmark with different challenges...... and needs, and two of these are presented. Based on the lessons learned, the Danish EPA has prepared a handbook to guide the user through the steps in a risk-based prioritization (Danish EPA, 2012). It provides guidance on prioritization both in an administratively defined area such as a Danish Region......, and within the bounds of a specified ground water catchment. The handbook presents several approaches in order to prevent the prioritization from foundering because of a lack of data or an inappropriate level of complexity. The developed prioritization tools, possible graphical presentation and use...

  19. Characterizing streamflow generation in Alpine catchments

    Science.gov (United States)

    Chiogna, Gabriele; Cano Paoli, Karina; Bellin, Alberto

    2016-04-01

    Developing effective hydrological models for streamflow generation in Alpine catchments is challenging due to the inherent complexity of the intertwined processes controlling water transfer from hillslopes to streams and along the river network. With water discharge as the sole observational variable it is impossible to differentiate between different streamflow sources, and modelling activity is often limited to simplified phenomenological rainfall-runoff models. This study focuses on quantifying streamflow sources at different temporal scales and the associated uncertainty by using natural tracer data (electrical conductivity, oxygen and hydrogen stable isotopes ratios) as observational variables supplementing streamflow measurements. We determine the spatial and temporal hydrological behavior and the mean residence time of water in the Vermigliana catchment, North-Eastern Italy and we separate contributions to streamflow originating from Presena and Presanella glaciers, both exerting a strong control on the hydrologic budget of the study site. Furthermore, we identify a seasonal control on the effect of storm events. The catchment responded rapidly to precipitation events in early autumn, it was unaffected by precipitation events in early spring, while runoff generation was enhanced by snow melting in late autumn. Air temperature is identified as the main controlling parameter, in addition to precipitation. Two-component mixing analysis showed that the relative contribution of new water, which can contribute up to 75% of total streamflow, is very rapid. Only two hours time-lag was observed between the beginning of the precipitation event and the emergence of a significant contribution of new water. These results evidence the relevance of mixing between pre-event and event water in the Vermigliana catchment, and in similar high elevation Alpine catchments. This study provides new insights on the dynamics of streamflow generation in Alpine catchments and a

  20. Estabilidad estructural y P en fracciones de agregados en la cuenca del Aº El Divisorio (Coronel Pringles, BA Structural stability and phosphorus in soil aggregate fractions in El Divisorio stream catchment area (Coronel Pringles, Buenos Aires province

    Directory of Open Access Journals (Sweden)

    Josefina Cacchiarelli

    2008-07-01

    Full Text Available En los últimos años la calidad del agua en el embalse Paso de las Piedras se ha visto afectada por la eutrofización, perjudicando la provisión para la población de Bahía Blanca y alrededores. Se ha señalado a la actividad agropecuaria como originaria del aumento de la concentración de fósforo (P en el arroyo El Divisorio, que desemboca en el embalse. El objetivo de este estudio fue cuantificar las relaciones entre algunas propiedades relacionadas con el potencial de contaminación de estos suelos: la estabilidad estructural, la distribución de tamaños de agregados y las concentraciones de las formas de P en los diferentes agregados. Se seleccionaron 16 transectas en lotes de productores a lo largo del curso del arroyo. Se tomaron muestras de suelo (0-5 cm en las posiciones loma (L, media loma (M y bajo (B. Se determinaron los diámetros medios ponderado en seco (DMPs y en húmedo (DMPh, calculándose el cambio en el diámetro medio ponderado (CDMP. Se determinaron los contenidos de P orgánico (Po e inorgánico (Pi en cada una de las posiciones y tamaños de agregados. Si bien los suelos de la cuenca mostraron buenos valores de estabilidad estructural, las fuerzas físicas provenientes de la actividad agrícola favorecieron la destrucción de los agregados menos estables encontrándose gran cantidad de material fino (In the last years, water quality in the Paso de las Piedras reservoir has been affected by eutrophication, leading to problems in the provision of potable water to the population of Bahía Blanca city and surrounding areas. Agricultural activity has been pointed out as the possible non-point source of P contaminating the El Divisorio stream, which flows directly into the reservoir. The objective of this work was to assess some selected edaphic properties associated with the contamination potential of soils such as structural stability, aggregate distribution and concentration of organic (Po and inorganic (Pi P in the

  1. Characterising water balance dynamics and different runoff components in a poorly gauged tropical catchment, Nicaragua

    Science.gov (United States)

    Calderon, Heyddy; Uhlenbrook, Stefan

    2014-05-01

    The water balance dynamics, groundwater flow systems and the runoff components of a tropical forested small catchment (46 km2) is the southwestern Pacific coast of Nicaragua were studied by a combination of hydrometry (observation of rainfall, runoff, evaporation and groundwater levels), geological characterisation (hydrogeological mapping, flow systems, characterization and Piper diagrams) and hydrochemical and isotopic tracers (chemograph analysis, 2- and 3-component hydrograph separation, discharge-hydrochemical hysteresis effects, and MWL). Although some methods can be considered standard in runoff generation research in temperate climate regions; to the best of our knowledge, this is one of the few studies that used the combination of these techniques in a tropical catchment of Central America. Runoff components were studied at different spatial and temporal scales, finding that different sources and temporal contributions are controlled by geology, catchment size, and dominant landscape elements. Two major groundwater flow systems were identified with different chemical and isotopic characteristics. Indication of moisture recycling in the upper catchment area was found based on d-excess analysis. Runoff components were studied at different spatial and temporal scales, demonstrating that different sources and temporal contributions are controlled by dominant landscape elements and precipitation distribution. Evidence of strong river-aquifer interactions in the lower part of the catchment was found. The results provide an in-depth understanding of the surface and groundwater contributions to stream flow and its temporal and spatial distribution, which indicate the importance of runoff generation areas upstream in the catchment and also the vulnerability of the alluvial aquifer to contamination. This provides the basis to develop realistic, evidence-based water management plans for this developing region.

  2. The role of seasonal and hydrological conditions in regulating dissolved inorganic nitrogen budgets in a forested catchment in SW Slovenia.

    Science.gov (United States)

    Rusjan, Simon; Vidmar, Andrej

    2017-01-01

    During two consecutive years the monitoring of rainfall nitrate (NO3(-)) and ammonium (NH4(+)) concentrations, combined with high-frequency measurements of streamwater NO3(-) concentrations, provided insight into the mechanisms controlling the dissolved inorganic nitrogen (DIN) budgets of the forested Padež stream catchment in SW Slovenia. During both years, the catchment's annual wet atmospheric DIN deposition (12.6 and 13.8kg-N/ha) exceeded the annual DIN export (10.7kg-N/ha and 8.8kg-N/ha). The analysis of the monthly DIN budgets discloses seasonal patterns. In winter and early spring, the catchment behaves as a net source of DIN, whereas during late spring, summer, and early fall the catchment generally behaves as a net sink of the atmospheric DIN. Due to large evapotranspiration in the growth period, most of the DIN remains in the catchment and is flushed during the dormant season. Despite high evapotranspiration and consequently low runoff coefficients characteristic for the Mediterranean climate, large rainfall events in the growth period can cause intensive washout of DIN from the catchment. At a monthly basis, the DIN flushing might exceed the catchment's DIN retention capacity and the catchment might behave as a net source of DIN. Therefore, the hydrological conditions have the ability to shift the catchment's role in regulating the DIN budgets. The high responsiveness of the streamwater NO3(-) concentration in the growth period indicates a large pool of DIN in the forest soils which can become mobile by runoff formation. Wet atmospheric DIN deposition at the Padež catchment is considerable; highest DIN inputs can be expected when air masses approach the catchment from the southwest to southeast where there are extensive urban areas along the Italian, Slovenian and Croatian coast. However, the Padež catchment does not appear to be approaching N saturation, presumably due to strong internal N cycle in the forest soils. Copyright © 2016 Elsevier B

  3. Integrated assessment of land use and cover changes in the Malagarasi river catchment in Tanzania

    Science.gov (United States)

    Kashaigili, J. J.; Majaliwa, A. M.

    Malagarasi river catchment represents one of the largest and most significant transboundary natural ecosystems in Africa. The catchment constitutes about one third of the catchment area of Lake Tanganyika and contains ecosystems of both national and international importance (i.e. Muyovozi Wetland Ramsar site). It has been increasingly said that increased anthropogenic activities have had negative impacts on the Muyovozi wetland in particular and other catchment resources. Nevertheless, these beliefs are little supported by quantitative data. A study on the dynamics of land use and cover in the Malagarasi river catchment therefore investigated long-term and seasonal changes that have occurred as a result of human activities in the area for the periods between 1984 and 2001. Landsat TM and ETM+ images were used to locate and quantify the changes. Perceptions of local people on historical changes and drivers for the changes were also collected and integrated in the assessment. The study revealed a significant change in land use and cover within a period of 18 year. Between 1984 and 2001, the woodland and wetland vegetation covers declined by 0.09% and 2.51% per year. Areas with settlements and cultivation increased by 1.05% annually while bushed grassland increased at 1.93% annually. The perceived principal drivers for the changes were found to include fire, cultivation along rivers and lake shores, overgrazing, poor law enforcement, insufficient knowledge on environmental issues, increasing poverty, deforestation and population growth. The human population growth rate stands at 4.8% against a national figure of 2.9%. The most perceived environmental problems include drying of streams and rivers, change in rainfall, loss of soil fertility, soil erosion and reduced crop yield. The study concludes that, there has been significant changes in land use and cover in the catchment and these require concerted actions to reverse the changes. The study highlights the importance

  4. Extending a rainfall-runoff model for lowland catchments from lumped to semi-distributed

    Science.gov (United States)

    Brauer, Claudia; Torfs, Paul; Teuling, Ryan; Uijlenhoet, Remko

    2016-04-01

    The Wageningen Lowland Runoff Simulator (WALRUS) is a parametric rainfall-runoff model for catchments with shallow groundwater (Brauer et al., 2014ab). WALRUS was developed using data and experience from two Dutch experimental catchments: the Hupsel Brook catchment (6.5 km2) and the Cabauw polder (0.5 km2). We identified key processes for runoff generation in lowland catchments, notably (1) groundwater-unsaturated zone coupling, (2) wetness-dependent flow routes, (3) groundwater-surface water feedbacks and (4) seepage and surface water supply, and accounted for these in the model structure. Up to now, WALRUS has been used in a lumped manner. However, water managers and researchers have expressed an interest in a semi-distributed version for application to larger catchments with varying forcing and catchment characteristics and to investigate the effect of groundwater flow within the catchment on modelled variables (e.g. groundwater depth). We combined WALRUS and a model for 2-dimensional groundwater flow into a simple modelling framework. WALRUS was already designed to cope with groundwater flow into or out of the model domain, because seepage and lateral groundwater flow are common in lowlands. In the semi-distributed version, we used this feature to couple different WALRUS elements (grid cells or subcatchments) to each other. Groundwater flow was computed using a digital elevation model, groundwater depths computed by WALRUS, soil transmissivity data and Darcy's law. Finally, we implemented a surface routing model including backwater effects, which are relevant in areas with little relief. With respect to the lumped version, the semi-distributed requires more data. Therefore, we investigated the added value of different data sources (forcing, elevation, soil, surface water) separately. We will present the rationale behind the semi-distributed model and show how the model structure compares to observations and and simulations without lateral transport. C.C. Brauer

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

    Directory of Open Access Journals (Sweden)

    R. J. Thayyen

    2010-02-01

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

  6. Tropical montane forest conversion affects spatial and temporal nitrogen dynamics in Kenyan headwater catchment

    Science.gov (United States)

    Jacobs, Suzanne; Weeser, Björn; Breuer, Lutz; Butterbach-Bahl, Klaus; Guzha, Alphonce; Rufino, Mariana

    2017-04-01

    export in catchments under managed land use. Furthermore, the changes in diurnal patterns in the forest catchment and absence of similar patterns in the other catchments are an indication that biogeochemical processes such as nitrification and denitrification in areas under different land use are affected as well. This could have implications for regional N-cycling.

  7. Pollution indicators in groundwater of two agricultural catchments in Lower Silesia (Poland)

    Science.gov (United States)

    Kasperczyk, Lidia; Modelska, Magdalena; Staśko, Stanisław

    2016-12-01

    The article discusses the content and source of mineral nitrogen compounds in groundwater, based on the data collected in two river catchments in two series (spring and autumn 2014). The study area comprises two catchments located in Lower Silesia, Poland - Cicha Woda and Sąsiecznica. Both catchments are characterised agricultural character of development. In the both researched areas, the points of State Environmental Monitoring (SEM) are located but only the Cicha Woda area is classified as nitrate vulnerable zone (NVZ). To analyse and compare the contamination of Quaternary and Neogene aquifers, the concentration of nitrates, nitrites, ammonium and potassium ions was measured primarily. Results showed the exceedance of nitrogen mineral forms of shallow groundwater Quaternary aquifer in both basins. The concentration of nitrates range from 0.08 to 142.12 mgNO3 -/dm3 (Cicha Woda) and from 2.6 to 137.65 mg NO3 -/dm3 (Sąsiecznica). The major source of pollution is probably the intensive agriculture activity. It causes a degradation of the shallow groundwater because of nitrate, nitrite, potassium, phosphates and ammonium contents. There was no observed contamination of anthropogenic origin in the deeper Neogene aquifer of Cicha Woda catchment.

  8. An INCA model for pathogens in rivers and catchments: Model structure, sensitivity analysis and application to the River Thames catchment, UK.

    Science.gov (United States)

    Whitehead, P G; Leckie, H; Rankinen, K; Butterfield, D; Futter, M N; Bussi, G

    2016-12-01

    Pathogens are an ongoing issue for catchment water management and quantifying their transport, loss and potential impacts at key locations, such as water abstractions for public supply and bathing sites, is an important aspect of catchment and coastal management. The Integrated Catchment Model (INCA) has been adapted to model the sources and sinks of pathogens and to capture the dominant dynamics and processes controlling pathogens in catchments. The model simulates the stores of pathogens in soils, sediments, rivers and groundwaters and can account for diffuse inputs of pathogens from agriculture, urban areas or atmospheric deposition. The model also allows for point source discharges from intensive livestock units or from sewage treatment works or any industrial input to river systems. Model equations are presented and the new pathogens model has been applied to the River Thames in order to assess total coliform (TC) responses under current and projected future land use. A Monte Carlo sensitivity analysis indicates that the input coliform estimates from agricultural sources and decay rates are the crucial parameters controlling pathogen behaviour. Whilst there are a number of uncertainties associated with the model that should be accounted for, INCA-Pathogens potentially provides a useful tool to inform policy decisions and manage pathogen loading in river systems. Copyright © 2016. Published by Elsevier B.V.

  9. Spatiotemporal dynamics of suspended sediment within an actively urbanizing peri-urban catchment in Portugal

    Science.gov (United States)

    Walsh, Rory; Ferreira, Carla; Ferreira, Antonio

    2016-04-01

    Suspended sediment levels tend to be enhanced in urban catchments, but vary considerably with (amongst many other factors) the degree of active urban development or redevelopment within the catchment and 'urbanization style'. Relatively little, however, is known about the relationship between suspended solids and urbanization style in peri-urban Mediterranean environments. This paper focuses on spatiotemporal suspended sediment dynamics within a typical Portuguese peri-urban catchment, Ribeira dos Covoes, that is undergoing rapid urbanization. The catchment currently has a 40% urban cover, with 17% impervious surfaces, dispersed between woodland (56%) and agricultural areas (4%). The study uses suspended sediment concentration measurements made at the catchment outlet (ESAC) and in three upstream tributaries: (i) Espírito Santo, with a largest urban area (49%); (ii) Porto Bordalo, 39% urbanized; and (iii) Quinta, 22% urbanized, most of which (18%) being an enterprise park under construction. Water sampling was carried out manually during 10 storm hydrographs between October 2011 and March 2013. Suspended sediment concentrations (SSC) were derived by laboratory analysis of the filtered samples using the gravimetric method. In addition total dissolved solids concentrations (TDS) were estimated using conductivity readings. Greatest SSCs were recorded in the Quinta sub-catchment and at the catchment outlet at ESAC (113-4320 mg L-1 and 200-1656 mg L-1, respectively) than in the Espírito Santo and Porto Bordalo sub-catchments (183-852 mg L-1 and 47-598 mg L-1 respectively, despite their greater impervious cover. The greatest SSCs for Quinta result from it containing the construction site, but it showed lower TDS (56-4010 mg L-1), perhaps due to the coarse sandy nature of the construction site. Higher TDS concentrations, however, were displayed in Porto Bordalo (27-5400 mg L-1), possibly due to the loamy soil. Espírito Santo, comprising sandy-loam soils, displayed 27

  10. Attributes for MRB_E2RF1 Catchments by Major River Basins in the Conterminous United States: Hydrologic Landscape Regions

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This tabular data set represents the area of Hydrologic Landscape Regions (HLR) compiled for every MRB_E2RF1 catchment of the Major River Basins (MRBs, Crawford and...

  11. Importance of including small-scale tile drain discharge in the calibration of a coupled groundwater-surface water catchment model

    DEFF Research Database (Denmark)

    Hansen, Anne Lausten; Refsgaard, Jens Christian; Christensen, Britt Stenhøj Baun;

    2013-01-01

    the catchment. In this study, a coupled groundwater-surface water model based on the MIKE SHE code was developed for the 4.7 km2 Lillebæk catchment in Denmark, where tile drain flow is a major contributor to the stream discharge. The catchment model was calibrated in several steps by incrementally including...... the observation data into the calibration to see the effect on model performance of including diverse data types, especially tile drain discharge. For the Lillebæk catchment, measurements of hydraulic head, daily stream discharge, and daily tile drain discharge from five small (1–4 ha) drainage areas exist....... The results showed that including tile drain data in the calibration of the catchment model improved its general performance for hydraulic heads and stream discharges. However, the model failed to correctly describe the local-scale dynamics of the tile drain discharges, and, furthermore, including the drain...

  12. Investigating the potential to reduce flood risk through catchment-based land management techniques and interventions in the River Roe catchment, Cumbria,UK

    Science.gov (United States)

    Pearson, Callum; Reaney, Sim; Bracken, Louise; Butler, Lucy

    2015-04-01

    potential to transfer these benefits to the Roe catchment (~69km2) have been assessed. Furthermore these flood mitigation features have the potential to deliver wider environmental improvements throughout the catchment and hence the potential for multiple benefits such as diffuse pollution reduction and habitat creation are considered. The research explores the impact of NFM techniques, flood storage areas or afforestation for example, with a view to enhancing local scale habitats. The research combines innovative catchment modelling techniques, both risk-based approaches (SCIMAP Flood) and spatially distributed hydrological simulation modelling (CRUM3), with in-field monitoring and observation of flow pathways and tributary response to rainfall using time-lapse cameras. Additional work with the local community and stakeholders will identify the range and location of potential catchment-based land management techniques and interventions being assessed; natural flood management implementation requires the participation and cooperation of landowners and local community to be successful (Howgate and Kenyon, 2009).

  13. Hydrological and erosional response of a small catchment in Sicily

    Science.gov (United States)

    Licciardello, Feliciana; Marcello Zimbone, Santo; Barbagallo, Salvatore; Gallart, Francesc

    2014-05-01

    More than 1/5 of the Italian territory is at risk of desertification involving over 40% of the South. Climate change is expected to worsen the desertification trend already observed. In Sicily, for instance, the semi-arid territory extension had been gradually increasing in the period from 1931 to 2000 up to 20% of the regional territory. Parallel to this, territories classified as humid decreased by 30%. A better knowledge of soil erosion by water is essential for planning effective soil and water conservation practices in semi-arid environment, where accurate soil loss predictions are difficult particularly in the absence of minimal data. In order to give a contribute to the understanding of hydrological and erosional dynamics in Mediterranean areas, a monitoring program of a small catchment started in 1996. The Cannata catchment (1.30 km2) is a mountainous tributary, ephemeral in flow, of the Flascio River located in eastern Sicily. Climate is Mediterranean semi-arid with a mean annual precipitation (1996-2005), measured in three different sites, equal to 715 ± 163 mm mainly falling between October and January. Mean monthly temperature is between 3°C (January) and 24°C (August). Land use monitoring highlighted the prevalence of pasture areas (ranging between 87% and 92% of the catchment area during the monitoring period). In the Cannata catchment the elevation ranges between 903 m and 1270 m above mean sea level with an average land slope of 21%. Water discharge has been measured continuously for about 10 years at the outlet of the catchment by means of a hydrometrograph station connected to a runoff water automatic sampler for the measurement of sediment concentration in the flow. Precipitation has a typically Mediterranean seasonal pattern, being minimal in summer and maximal in winter. Monthly runoff follows the pattern of precipitation although somewhat delayed during autumn due to the effect of water deficit in summer. The analysis of the 170 runoff

  14. Try This: Construct a Water Catchment

    Science.gov (United States)

    Teaching Science, 2017

    2017-01-01

    EngQuest, an initiative of Engineers Australia, provides an exciting, non-competitive way for students to participate in free, fun and educational engineering activities involving mathematics, science and technology. This article describes a project designed to teach middle school students how to construct a water catchment system. Water…

  15. Hydrological Modelling of Small Catchments Using Swat

    Science.gov (United States)

    Kannan, N.; White, S. M.; Worrall, F.; Groves, S.

    The data from a 142ha catchment in Eastern England(Colworth, Bedfordshire)are be- ing used to investigate the performance of the USDA SWAT software for modelling hydrology of small catchments. Stream flow at the catchment outlet has been mon- itored since October 1999. About 50% of the total catchment is directly controlled within one farm and a rotation of wheat, oil seed rape, grass, linseed, beans and peas is grown. Three years of stream flow and climate data are available. Calibration and validation of stream flow was carried out with both runoff modelling options in the SWAT model (USDA curve number method and the Green and Ampt method). The Nash and Sutcliffe efficiencies for the calibration period were 66% and 63% respec- tively. The performance of SWAT was better in the validation period as a whole, with regard to timing of peaks, baseflow values and Nash and Sutcliffe efficiency. An ef- ficiency of 70% was obtained using the curve number method, which is comparable with the efficiencies obtainable with more complex models. Despite this performance, SWAT is under predicting stream flow peaks. A detailed investigation of important model components, has allowed us to identify some of the reasons for under predic- tion of stream flow peaks.

  16. Evaluating an ecosystem management approach for improving water quality in two contrasting study catchments in south-west England.

    Science.gov (United States)

    Glendell, Miriam; Brazier, Richard

    2014-05-01

    The European Water Framework Directive (WFD) 2000 established a new emphasis for the management of freshwaters by establishing ecologically-based water quality targets that are to be achieved through holistic, catchment-scale, ecosystem management approaches. However, significant knowledge gaps still exist in the understanding of the cumulative effectiveness of multiple mitigation measures on a number of pollutants at a catchment scale. This research furthers the understanding of the effectiveness of an ecosystem management approach to deliver catchment-scale water quality improvements in two contrasting study catchments in south-west England: the lowland agricultural Aller and the upland semi-natural Horner Water. Characterisation of the spatial variability of soil properties (bulk density, total carbon, nitrogen, C:N ratio, stable isotope δ15N, total, organic and inorganic phosphorus) in the two study catchments demonstrated extensive alteration of soil properties in the agricultural catchment, with likely long-term implications for the restoration of ecosystem functioning and water quality management (Glendell et al., 2014b). Further, the agricultural catchment supported a proportionally greater total fluvial carbon (dissolved and particulate) export than the semi-natural catchment. During an eight month period for which a comparable continuous turbidity record was available, the estimated SS yields from the agricultural catchment (25.5-116.2 t km-2) were higher than from the semi-natural catchment (21.7-57.8 t km-2). In addition, the agricultural catchment exported proportionally more TPC (0.51-2.59 kg mm-1) than the semi-natural catchment (0.36-0.97 kg mm-1) and a similar amount of DOC (0.26-0.52 kg mm-1 in the Aller and 0.24-0.32 kg mm-1 in Horner Water), when normalised by catchment area and total discharge, despite the lower total soil carbon pool, thus indicating an enhanced fluvial loss of sediment and carbon (Glendell and Brazier, in review). Whilst

  17. Catchment scale afforestation for mitigating flooding

    Science.gov (United States)

    Barnes, Mhari; Quinn, Paul; Bathurst, James; Birkinshaw, Stephen

    2016-04-01

    After the 2013-14 floods in the UK there were calls to 'forest the uplands' as a solution to reducing flood risk across the nation. At present, 1 in 6 homes in Britain are at risk of flooding and current EU legislation demands a sustainable, 'nature-based solution'. However, the role of forests as a natural flood management technique remains highly controversial, due to a distinct lack of robust evidence into its effectiveness in reducing flood risk during extreme events. SHETRAN, physically-based spatially-distributed hydrological models of the Irthing catchment and Wark forest sub-catchments (northern England) have been developed in order to test the hypothesis of the effect trees have on flood magnitude. The advanced physically-based models have been designed to model scale-related responses from 1, through 10, to 100km2, a first study of the extent to which afforestation and woody debris runoff attenuation features (RAFs) may help to mitigate floods at the full catchment scale (100-1000 km2) and on a national basis. Furthermore, there is a need to analyse the extent to which land management practices, and the installation of nature-based RAFs, such as woody debris dams, in headwater catchments can attenuate flood-wave movement, and potentially reduce downstream flood risk. The impacts of riparian planting and the benefits of adding large woody debris of several designs and on differing sizes of channels has also been simulated using advanced hydrodynamic (HiPIMS) and hydrological modelling (SHETRAN). With the aim of determining the effect forestry may have on flood frequency, 1000 years of generated rainfall data representative of current conditions has been used to determine the difference between current land-cover, different distributions of forest cover and the defining scenarios - complete forest removal and complete afforestation of the catchment. The simulations show the percentage of forestry required to have a significant impact on mitigating

  18. Stakeholder discourse and water management in a catchment in northern Italy

    Directory of Open Access Journals (Sweden)

    P. S. Lupo Stanghellini

    2007-06-01

    Full Text Available The Water Framework Directive (WFD; directive 2000/60/EC was created to ensure the sustainable use of water resources in the European Union. A central guideline included throughout the directive is a call for the participation of stakeholders in the management of these resources. Involving stakeholders is an important step to ensure that catchment management plans take into consideration local experience in the development of these plans and the impact of the plans on local interests. This paper describes and analyses the results of a series of workshops to facilitate implementation of the WFD at a catchment level based on the stakeholder participation model, CATCH.

    To test the usefulness of the stakeholder participation model CATCH for water management in a catchment area, a sub-catchment in an alpine valley in the north-east of Italy, the Alta Valsugana in the Province of Trento, was chosen as the setting for a series of workshops. In this valley water is fundamental for activities associated with agriculture, domestic use, energy production, sports and recreation. In the recent past the valley has had serious problems related to water quality and quantity. Implementation of water management plans under the WFD may lead to conflicts within the catchment between different stakeholder interest groups. Including stakeholders in the development of management plans not only follows the guidelines of the WFD but also could result in a more locally adapted and acceptable plan for the catchment.

    A new stakeholder analysis methodology was developed and implemented in order to identify the relevant stakeholders of the area and then two sets of workshops involving the key stakeholders identified were conducted in Spring 2006. The CATCH meetings were a new experience for the participants, who had to deal with both the principles of the WFD in general and the participation requirement in particular. During the meetings, the CATCH model

  19. Physical and human influences on fluvial water quality in the Tagus river catchment, Portugal

    Science.gov (United States)

    Nunes, A.

    2009-04-01

    Rivers are important resources of drinkable water, ecosystems with a high biologic potency and places of entertainment. Water quality at the catchment scale depends on climate, geology, geomorphology, soils and mainly of land use and land cover. Different activities such as agriculture, livestock, industrial and urban drains have promoted the deterioration of the fluvial water quality. The announced climate changes, the increase of food requirements, as well as the urban concentration of people pose new challenges for the assessment and sustainable management of water quality on the catchment scale. At present about 2/3 of portuguese population live near coast, in urban centers. Since the last three decades, the largest part of the marginal agricultural land has been abandoned whilst the most productive soils have experienced an intensification on its productivity. The Tagus river catchment, with an area of 24.850 km2 only in the Portuguese territory, shows very important contrasts in climate, geology, geomorphology, land use and population density. The main objectives of this work are to evaluate and compare the surface water quality in different sub catchments of Tagus river and to contribute to a better understanding of how physical and human factors (such as geology, precipitation, temperature, runoff, land use and land cover and population density) interfere in their spatial-temporal variability. In order to achieve this issue, twenty sub catchments were selected. The chosen catchments show different locations and areas, and a quite long data series of physical, chemical and biology properties of water, such as nitrates, phosphates, dissolved oxygen, total coliforms, etc. Making use of Geographic Information System (GIS) tools, a database was created for each sub-catchment containing all the physical and human characteristics. Afterwards, statistical analysis was carried out by using SPSS programme (11.0 for Windows. One-way analysis of variance and the Tukey

  20. Catchment areas of panoramic snapshots in outdoor scenes

    Science.gov (United States)

    Zeil, Jochen; Hofmann, Martin I.; Chahl, Javaan S.

    2003-03-01

    We took panoramic snapshots in outdoor scenes at regular intervals in two- or three-dimensional grids covering 1 m2 or 1 m3 and determined how the root mean square pixel differences between each of the images and a reference image acquired at one of the locations in the grid develop over distance from the reference position. We then asked whether the reference position can be pinpointed from a random starting position by moving the panoramic imaging device in such a way that the image differences relative to the reference image are minimized. We find that on time scales of minutes to hours, outdoor locations are accurately defined by a clear, sharp minimum in a smooth three-dimensional (3D) volume of image differences (the 3D difference function). 3D difference functions depend on the spatial-frequency content of natural scenes and on the spatial layout of objects therein. They become steeper in the vicinity of dominant objects. Their shape and smoothness, however, are affected by changes in illumination and shadows. The difference functions generated by rotation are similar in shape to those generated by translation, but their plateau values are higher. Rotational difference functions change little with distance from the reference location. Simple gradient descent methods are surprisingly successful in recovering a goal location, even if faced with transient changes in illumination. Our results show that view-based homing with panoramic images is in principle feasible in natural environments and does not require the identification of individual landmarks. We discuss the relevance of our findings to the study of robot and insect homing.

  1. First Flush Effects in an Urban Catchment Area in Aalborg

    DEFF Research Database (Denmark)

    Larsen, Torben; Broch, Kirsten; Andersen, Margit Riis

    1997-01-01

    events with time series of concentration of SS, COD, BOD, total nitrogen and total phosphorus. The quality parameters showed significant first flush effects. The paper discusses whether either the event average concentration or the accumulated event mass is the most appropriate way to characterize...

  2. Heavy metals in the Ljubljanica catchment area (Slovenia

    Directory of Open Access Journals (Sweden)

    Branka Trček

    2006-12-01

    Full Text Available In main springs and swallowholes of the Ljubljanica River Basin the monitoring of heavy metals was established at the beginning of 2005 with the intention to study the solute transport in the water body and to analyse the risk of contamination with heavy metals. The results of the first monitoring phase are presented–elements that indicate the load of environment due to industry, traffic,agriculture and urbanisation:Al,As,Cd,Cl,Cr,Cu,Mn in Pb. The results point out that the vulnerability of karst aquifers depends on aquifer hydrodynamic conditions, infiltration conditions and development of a karst drainage system. Furthermore, they indicated the local and regional geochemical and hydrogeological characteristics and enable to evidence the main processes and effects that impact on environmental changes.

  3. Seasonalstreamflow Generation At Variousspatial Scales On A Smallmediterranean Vineyard Catchment

    Science.gov (United States)

    Marofi, S.; Moussa, R.; Voltz, M.

    The importance of surface hydrological processes, under field and sub-catchment conditions, was examines on a small-cultivated watershed, located in South of France. Hydrological responses at different spatial scales were evaluated during the wetness and drier phases, which included the within-year and the long-term periods. The experimental design involved monitoring of surface runoff, streamflow and groundwaters behaviours, in response to rainfall events, during three hydrological cycles. In addition to the mean outlet of catchment and the two vineyard fields that have different situations, runoff was measured at 8 sub-catchments of site. Rainfall was monitored on continuous basis at 4 sites, and the water tables fluctuations also were recorded in more than 15 locations of catchment. During the experimentation period, more than 175 rainy events were observed. The dates analyse show that the regime of surface water, compound of three principals phases: (i) the phases of great flow circulation, (ii) the recession phases, and (iii) the phase without surface flow. The results also indicate that the annual runoff changes appreciably according to hydrological cycles and the rainfall variability. It varies from 28% to 50% of the total of precipitation. The inter-annual variations of the runoff also recovers that the annual runoff flow is insured for approximately 40% by the instantaneous floods, which occur the moment or a few hours only after precipitation, and about 60% by the recession periods, which take place for the long time after floods. The flood events were classified in three groups, differentiated by the initial water table levels and their occurrence period. The direct runoff and the baseflow calculation show that according to the type of flood, they change respectively from 7% to17% and 0% to 7% of precipitation. Comparing to the field areas, on average, the total runoff and direct runoff of the mean basin respectively are 46% and 35%. The water flow

  4. Carbon fluxes in an acid rain impacted boreal headwater catchment

    Science.gov (United States)

    Marx, Anne; Hintze, Simone; Jankovec, Jakub; Sanda, Martin; Dusek, Jaromir; Vogel, Tomas; van Geldern, Robert; Barth, Johannes A. C.

    2016-04-01

    Terrestrial carbon export via inland aquatic systems is a key process in the budget of the global carbon cycle. This includes loss of carbon to the atmosphere via gas evasion from rivers or reservoirs as well as carbon fixation in freshwater sediments. Headwater streams are the first endmembers of the transition of carbon between soils, groundwater and surface waters and the atmosphere. In order to quantify these processes the experimental catchment Uhlirska (1.78 km2) located in the northern Czech Republic was studied. Dissolved inorganic, dissolved organic and particulate organic carbon (DIC, DOC, POC) concentrations and isotopes were analyzed in ground-, soil -and stream waters between 2014 and 2015. In addition, carbon dioxide degassing was quantified via a stable isotope modelling approach. Results show a discharge-weighted total carbon export of 31.99 g C m-2 yr-1 of which CO2 degassing accounts 79 %. Carbon isotope ratios (δ13C) of DIC, DOC, and POC (in ‰ VPDB) ranged from -26.6 to -12.4 ‰ from -29.4 to -22.7 ‰ and from -30.6 to -26.6 ‰ respectively. The mean values for DIC are -21.8 ±3.8 ‰ -23.6 ±0.9 ‰ and -19.5 ±3.0 ‰ for soil, shallow ground and surface water compartments. For DOC, these compartments have mean values of -27.1 ±0.3 ‰ -27.0 ±0.8 ‰ and -27.4 ±0.7 ‰Ṁean POC value of shallow groundwaters and surface waters are -28.8 ±0.8 ‰ and -29.3 ±0.5 ‰ respectively. These isotope ranges indicate little turnover of organic material and predominant silicate weathering. The degassing of CO2 caused an enrichment of the δ13C-DIC values of up to 6.8 ‰ between a catchment gauge and the catchment outlet over a distance of 866 m. In addition, the Uhlirska catchment has only negligible natural sources of sulphate, yet SO42- accounts for 21 % of major stream water ions. This is most likely a remainder from acid rain impacts in the area.

  5. A two-step Floating Catchment Area (2SFCA) Method for Measuring Spatial Accessibility to Primary Healthcare Searvice in China: A Case Study of Donghai County in Jiangsu Province%就医空间可达性分析的两步移动搜索法——以江苏省东海县为例

    Institute of Scientific and Technical Information of China (English)

    胡瑞山; 董锁成; 胡浩

    2012-01-01

    In the poor rural areas of China, the population far away from the hospitals, not having immediate access to primary care, is showing rising trend on a yearly basis. The measures to improve the spatial accessibility to primary care in the poor areas are important for achieving equality in the public healthcare system in rural regions. To accurately evaluate the variations of the accessibility to medical services is a prerequisite for rationally allocating medical resources. After reviewing the studies at home and abroad on spatial accessibility to medical services, by using the two step floating catchment area (2SFCA) method in the case study of Donghai County in Jiangsu province, and taking administrative villages and hospitals as study units, this paper analyzes the variations between the villages' levels of the accessibility to primary care based on the shortest travel time from a village to a hospital calculated by Dijkstra method. In order to investigate the spatial distribution of the areas lacking access to primary care, the authors further analyze the spatial variations of the accessibility by choosing two service time threshold values (catchment sizes). In comparison to traditional measures such as ratio of population to provider (demand to supply), distance/time to the nearest service provider and gravity model, the 2SFCA method reveals a good spatial pattern of the variations of the accessibility to primary care. When a bigger ser- vice time threshold value is used, the spatial variations tend to be smoother. When a smaller service time thresh-old value is used, the spatial variations become more striking and the area lacking the access to primary care expands. The spatial pattern of the variations of the accessibility to primary care in Donghai County has characteristics of a single core structure. The areas along major transportation networks have higher levels of spatial ac- cessibility, while the remote villages and townships lack the access

  6. Applying the Fuzzy ARTMAP neural network for mapping erosive status in the Ria Formosa catchment (Portugal)

    Science.gov (United States)

    Granja Martins, F. M.; Neto Paixão, H. M.; Jordán, A.; Zavala, L. M.; Bellinfante, N.

    2012-04-01

    The study of the soil erosion risk is the starting point for development and sustainable land management. The intensity of soil erosion risk is conditioned by soil erodibility, slope, land use and vegetation cover. The objective of this work is mapping the erosive status of the Ria Formosa catchment using "Fuzzy ARTMAP" neural network. The study area is the catchment of Ria Formosa, which includes a shallow coastal lagoon with an area of about 16000 ha located in Algarve (southern Portugal). It is protected by EU and national laws, and is classified as a wetland of international importance under the RAMSAR convention. Previously to the construction of the artificial neuronal network model, it was necessary to establish the training areas (proposed by the Priority Action Plan/Regional Activity Centre (PAP/RAC, 1997). The differences between both methods were about 1% of the total area. Both maps were validated with field observations and analysis of aerial photographs.

  7. Lake metabolism scales with lake morphometry and catchment conditions

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Baastrup-Spohr, Lars; Jensen, Kaj Sand;

    2012-01-01

    We used a comparative data set for 25 lakes in Denmark sampled during summer to explore the influence of lake morphometry, catchment conditions, light availability and nutrient input on lake metabolism. We found that (1) gross primary production (GPP) and community respiration (R) decline with lake...... area, water depth and drainage ratio, and increase with algal biomass (Chl), dissolved organic carbon (DOC) and total phosphorus (TP); (2) all lakes, especially small with less incident light, and forest lakes with high DOC, have negative net ecosystem production (NEP ... decreases with lake area and water depth as a consequence of lower input of nutrients and organic matter per unit water volume; (4) the influence of benthic processes on free water metabolic measures declines with increasing lake size; and (5) with increasing lake size, lake metabolism decreases...

  8. Regional lead isotope study of a polluted river catchment: River Wear, Northern England, UK.

    Science.gov (United States)

    Shepherd, Thomas J; Chenery, Simon R N; Pashley, Vanessa; Lord, Richard A; Ander, Louise E; Breward, Neil; Hobbs, Susan F; Horstwood, Matthew; Klinck, Benjamin A; Worrall, Fred

    2009-08-15

    High precision, lead isotope analyses of archived stream sediments from the River Wear catchment, northeast England (1986-88), provide evidence for three main sources of anthropogenic lead pollution; lead mining, industrial lead emissions and leaded petrol. In the upper catchment, pollution is totally controlled and dominated by large lead discharges from historic mining centres in the North Pennine Orefield ((208)Pb/(206)Pb, (207)Pb/(206)Pb ratios range from 2.0744-2.0954 and 0.8413-0.8554 respectively). In the lower catchment, co-extensive with the Durham Coalfield and areas of high population density, pollution levels are lower and regionally more uniform. Isotope ratios are systematically higher than in the upper catchment ((208)Pb/(206)Pb, (207)Pb/(206)Pb ratios range from 2.0856-2.1397 and 0.8554-0.8896 respectively) and far exceed values determined for the geogenic regional background. Here, the pollution is characterised by the atmospheric deposition of industrial lead and petrol lead. Lead derived from the combustion of coal, although present, is masked by the other two sources. Recent sediments from the main channel of the River Wear are isotopically indistinguishable from older, low order stream sediments of the North Pennine Orefield, indicating that contamination of the river by lead mining waste (up to several 1000 mg/kg Pb at some locations) continues to pose an environmental problem; a pattern that can be traced all the way to the tidal reach. Using within-catchment isotope variation and sediment lead concentrations, estimates can be made of the discharges from discrete mines or groups of mines to the overall level of lead pollution in the River Wear. As well as providing information pertinent to source apportionment and on-going catchment remediation measures, the database is a valuable resource for epidemiologists concerned with the health risks posed by environmental lead.

  9. Regional lead isotope study of a polluted river catchment: River Wear, Northern England, UK

    Energy Technology Data Exchange (ETDEWEB)

    Shepherd, Thomas J., E-mail: shepherdtj@aol.com [Department of Earth Sciences, University of Durham, Science Laboratories, Durham DH1 3LE (United Kingdom); Chenery, Simon R.N. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Pashley, Vanessa [NERC Isotope Geosciences Laboratory, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG (United Kingdom); Lord, Richard A. [School of Science and Technology, University of Teesside, Middlesbrough, Tees Valley TS1 3BA (United Kingdom); Ander, Louise E.; Breward, Neil; Hobbs, Susan F. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Horstwood, Matthew [NERC Isotope Geosciences Laboratory, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG (United Kingdom); Klinck, Benjamin A. [British Geological Survey, Nicker Hill, Keyworth, Nottingham NG12 5GG (United Kingdom); Worrall, Fred [Department of Earth Sciences, University of Durham, Science Laboratories, Durham DH1 3LE (United Kingdom)

    2009-08-15

    High precision, lead isotope analyses of archived stream sediments from the River Wear catchment, northeast England (1986-88), provide evidence for three main sources of anthropogenic lead pollution; lead mining, industrial lead emissions and leaded petrol. In the upper catchment, pollution is totally controlled and dominated by large lead discharges from historic mining centres in the North Pennine Orefield ({sup 208}Pb/{sup 206}Pb, {sup 207}Pb/{sup 206}Pb ratios range from 2.0744-2.0954 and 0.8413-0.8554 respectively). In the lower catchment, co-extensive with the Durham Coalfield and areas of high population density, pollution levels are lower and regionally more uniform. Isotope ratios are systematically higher than in the upper catchment ({sup 208}Pb/{sup 206}Pb, {sup 207}Pb/{sup 206}Pb ratios range from 2.0856-2.1397 and 0.8554-0.8896 respectively) and far exceed values determined for the geogenic regional background. Here, the pollution is characterised by the atmospheric deposition of industrial lead and petrol lead. Lead derived from the combustion of coal, although present, is masked by the other two sources. Recent sediments from the main channel of the River Wear are isotopically indistinguishable from older, low order stream sediments of the North Pennine Orefield, indicating that contamination of the river by lead mining waste (up to several 1000 mg/kg Pb at some locations) continues to pose an environmental problem; a pattern that can be traced all the way to the tidal reach. Using within-catchment isotope variation and sediment lead concentrations, estimates can be made of the discharges from discrete mines or groups of mines to the overall level of lead pollution in the River Wear. As well as providing information pertinent to source apportionment and on-going catchment remediation measures, the database is a valuable resource for epidemiologists concerned with the health risks posed by environmental lead.

  10. The Wageningen Lowland Runoff Simulator (WALRUS: application to the Hupsel Brook catchment and Cabauw polder

    Directory of Open Access Journals (Sweden)

    C. C. Brauer

    2014-02-01

    Full Text Available The Wageningen Lowland Runoff Simulator (WALRUS is a new parametric (conceptual rainfall-runoff model which accounts explicitly for processes that are important in lowland areas, such as groundwater-unsaturated zone coupling, wetness-dependent flowroutes, groundwater–surface water feedbacks, and seepage and surface water supply (see companion paper by Brauer et al., 2014. Lowland catchments can be divided into slightly sloping, freely draining catchments and flat polders with controlled water levels. Here, we apply WALRUS to two contrasting Dutch catchments: the Hupsel Brook catchment and Cabauw polder. In both catchments, WALRUS performs well: Nash–Sutcliffe efficiencies obtained after calibration on one year of discharge observations are 0.87 for the Hupsel Brook catchment and 0.83 for the Cabauw polder, with values of 0.74 and 0.76 for validation. The model also performs well during floods and droughts and can forecast the effect of control operations. Through the dynamic division between quick and slow flowroutes controlled by a wetness index, temporal and spatial variability in groundwater depths can be accounted for, which results in adequate simulation of discharge peaks as well as low flows. The performance of WALRUS is most sensitive to the parameter controlling the wetness index and the groundwater reservoir constant, and to a lesser extent to the quickflow reservoir constant. The effects of these three parameters can be identified in the discharge time series, which indicates that the model is not overparameterised (parsimonious. Forcing uncertainty was found to have a larger effect on modelled discharge than parameter uncertainty and uncertainty in initial conditions.

  11. The Wageningen Lowland Runoff Simulator (WALRUS): application to the Hupsel Brook catchment and the Cabauw polder

    Science.gov (United States)

    Brauer, C. C.; Torfs, P. J. J. F.; Teuling, A. J.; Uijlenhoet, R.

    2014-10-01

    The Wageningen Lowland Runoff Simulator (WALRUS) is a new parametric (conceptual) rainfall-runoff model which accounts explicitly for processes that are important in lowland areas, such as groundwater-unsaturated zone coupling, wetness-dependent flowroutes, groundwater-surface water feedbacks, and seepage and surface water supply (see companion paper by Brauer et al., 2014). Lowland catchments can be divided into slightly sloping, freely draining catchments and flat polders with controlled water levels. Here, we apply WALRUS to two contrasting Dutch catchments: the Hupsel Brook catchment and the Cabauw polder. In both catchments, WALRUS performs well: Nash-Sutcliffe efficiencies obtained after calibration on 1 year of discharge observations are 0.87 for the Hupsel Brook catchment and 0.83 for the Cabauw polder, with values of 0.74 and 0.76 for validation. The model also performs well during floods and droughts and can forecast the effect of control operations. Through the dynamic division between quick and slow flowroutes controlled by a wetness index, temporal and spatial variability in groundwater depths can be accounted for, which results in adequate simulation of discharge peaks as well as low flows. The performance of WALRUS is most sensitive to the parameter controlling the wetness index and the groundwater reservoir constant, and to a lesser extent to the quickflow reservoir constant. The effects of these three parameters can be identified in the discharge time series, which indicates that the model is not overparameterised (parsimonious). Forcing uncertainty was found to have a larger effect on modelled discharge than parameter uncertainty and uncertainty in initial conditions.

  12. The Wageningen Lowland Runoff Simulator (WALRUS): application to the Hupsel Brook catchment and Cabauw polder

    Science.gov (United States)

    Brauer, C. C.; Torfs, P. J. J. F.; Teuling, A. J.; Uijlenhoet, R.

    2014-02-01

    The Wageningen Lowland Runoff Simulator (WALRUS) is a new parametric (conceptual) rainfall-runoff model which accounts explicitly for processes that are important in lowland areas, such as groundwater-unsaturated zone coupling, wetness-dependent flowroutes, groundwater-surface water feedbacks, and seepage and surface water supply (see companion paper by Brauer et al., 2014). Lowland catchments can be divided into slightly sloping, freely draining catchments and flat polders with controlled water levels. Here, we apply WALRUS to two contrasting Dutch catchments: the Hupsel Brook catchment and Cabauw polder. In both catchments, WALRUS performs well: Nash-Sutcliffe efficiencies obtained after calibration on one year of discharge observations are 0.87 for the Hupsel Brook catchment and 0.83 for the Cabauw polder, with values of 0.74 and 0.76 for validation. The model also performs well during floods and droughts and can forecast the effect of control operations. Through the dynamic division between quick and slow flowroutes controlled by a wetness index, temporal and spatial variability in groundwater depths can be accounted for, which results in adequate simulation of discharge peaks as well as low flows. The performance of WALRUS is most sensitive to the parameter controlling the wetness index and the groundwater reservoir constant, and to a lesser extent to the quickflow reservoir constant. The effects of these three parameters can be identified in the discharge time series, which indicates that the model is not overparameterised (parsimonious). Forcing uncertainty was found to have a larger effect on modelled discharge than parameter uncertainty and uncertainty in initial conditions.

  13. Predicting diffuse microbial pollution risk across catchments: The performance of SCIMAP and recommendations for future development.

    Science.gov (United States)

    Porter, Kenneth D H; Reaney, Sim M; Quilliam, Richard S; Burgess, Chris; Oliver, David M

    2017-12-31

    Microbial pollution of surface waters in agricultural catchments can be a consequence of poor farm management practices, such as excessive stocking of livestock on vulnerable land or inappropriate handling of manures and slurries. Catchment interventions such as fencing of watercourses, streamside buffer strips and constructed wetlands have the potential to reduce faecal pollution of watercourses. However these interventions are expensive and occupy valuable productive land. There is, therefore, a requirement for tools to assist in the spatial targeting of such interventions to areas where they will have the biggest impact on water quality improvements whist occupying the minimal amount of productive land. SCIMAP is a risk-based model that has been developed for this purpose but with a focus on diffuse sediment and nutrient pollution. In this study we investigated the performance of SCIMAP in predicting microbial pollution of watercourses and assessed modelled outputs of E. coli, a common faecal indicator organism (FIO), against observed water quality information. SCIMAP was applied to two river catchments in the UK. SCIMAP uses land cover risk weightings, which are routed through the landscape based on hydrological connectivity to generate catchment scale maps of relative in-stream pollution risk. Assessment of the model's performance and derivation of optimum land cover risk weightings was achieved using a Monte-Carlo sampling approach. Performance of the SCIMAP framework for informing on FIO risk was variable with better performance in the Yealm catchment (rs=0.88; p0.05). Across both catchments much uncertainty was associated with the application of optimum risk weightings attributed to different land use classes. Overall, SCIMAP showed potential as a useful tool in the spatial targeting of FIO diffuse pollution management strategies; however, improvements are required to transition the existing SCIMAP framework to a robust FIO risk-mapping tool. Copyright

  14. A participatory approach for Integrated River Basin Management in the Elbe catchment

    Science.gov (United States)

    Nunneri, C.; Hofmann, J.

    2005-02-01

    This paper presents a qualitative analysis of a series of in-depth interviews with governmental and non-governmental institutions (NGOs). Within the EUROCAT 1 project this methodology of participatory approach, aiming to scope the present perceptions about environmental issues and possible strategies for environmental improvement, is applied to the study of the Elbe catchment for the first time. In this frame, an Advisory Board (AB) was created, with the aim of giving insights into conflicting interests in the river catchment and guidelines for river basin management. Focus of the Elbe case study is the issue of nutrient enrichment (from the catchment) and the induced eutrophication of the coastal waters (the German Bight). Specifically, regarding this topic, the possible reduction of eutrophication in the German Bight by a (policy driven) decrease in nutrient inputs from the catchment area is analysed. Different measures for reducing the input of nutrients from the catchment, and ultimately preventing eutrophication of the coastal waters are considered. In this context, the members of the AB were asked about the efficiency and feasibility of different measures and the criteria for choosing 'better' management solutions among the possible ones. Although there is a general agreement about the necessity of reducing nutrient emissions, some members of the AB perceive other environmental issues (e.g. altered morphodynamics) as more relevant than nutrient enrichment. Voluntary cooperation, eco-efficiency and 'trans-sectoral' communication are the key concepts mentioned as being indispensable for integrated management. The (public) acceptance of measures for nutrient reduction have to find its way through compromises and social equity, allowing for win-win solutions among different groups of interests and balanced spatial division of costs and benefits. EUROpean CATchments, Project N° EVK1-CT-2000-00044 ( http://www.iia-cnr.unical.it/EUROCAT/project.htm).

  15. Spatial Modelling of Sediment Transport over the Upper Citarum Catchment

    Directory of Open Access Journals (Sweden)

    Poerbandono

    2006-05-01

    Full Text Available This paper discusses set up of a spatial model applied in Geographic Information System (GIS environment for predicting annual erosion rate and sediment yield of a watershed. The study area is situated in the Upper Citarum Catchment of West Java. Annual sediment yield is considered as product of erosion rate and sediment delivery ratio to be modelled under similar modeling tool. Sediment delivery ratio is estimated on the basis of sediment resident time. The modeling concept is based on the calculation of water flow velocity through sub-catchment surface, which is controlled by topography, rainfall, soil characteristics and various types of land use. Relating velocity to known distance across digital elevation model, sediment resident time can be estimated. Data from relevance authorities are used. Bearing in mind limited knowledge of some governing factors due to lack of observation, the result has shown the potential of GIS for spatially modeling regional sediment transport. Validation of model result is carried out by evaluating measured and computed total sediment yield at the main outlet. Computed total sediment yields for 1994 and 2001 are found to be 1.96×106 and 2.10×106tons/year. They deviate roughly 54 and 8% with respect to those measured in the field. Model response due to land use change observed in 2001 and 1994 is also recognised. Under presumably constant rainfall depth, an increase of overall average annual erosion rate of 11% resulted in an increase of overall average sediment yield of 7%.

  16. Assessing pesticide exposure of the aquatic environment in tropical catchments

    Science.gov (United States)

    Weiss, Frederik; Zurbrügg, Christian; Eggen, Rik; Castillo, Luisa; Ruepert, Clemens; Stamm, Christian

    2015-04-01

    Today, pesticides are intensively used in agriculture across the globe. Worldwide about 2.4×106 tons of pesticides are used annually on 1.6×109 ha of arable land. This yields a global average use of pesticides of 1.53 kg ha-1 year-1. Available data suggest that the use in the agricultural sector will continue to grow. Recently it was estimated that within the last decade, the world pesticide market increased by 93% and the Brazilian market alone by 190%. Though pesticides are intensively used in many low and middle income countries (LAMICs), scientifically sound data of amounts and types of pesticide use and the resulting impact on water quality are lacking in many of these countries. Therefore it is highly relevant to: i) identify risk areas where pesticides affect environmental health, ii) understand the environmental behavior of pesticides in vulnerable tropical ecosystems; and iii) develop possible mitigation options to reduce their exposure to ecosystems and humans. Here we present a project that will focus on assessing pesticide exposure of the aquatic environment and humans in tropical catchments of LAMICs. A catchment in the Zarcero province in Costa Rica will be the test case. Pesticide exposure will be assessed by passive sampling. In order to cover a broad range of compounds of possible use, two sampling devices will be used: SDB membranes for collecting polar compounds and silicon sheets for accumulating apolar pesticides. Extracts will be subsequently analysed by GC-MSMS and LC-HRMS.

  17. Black, grey and white-box approaches to understanding catchment-wide hydrologic connectivity

    Science.gov (United States)

    Ali, G. A.; Roy, A. G.

    2009-12-01

    Connectivity is associated with nonlinear hydrological responses as it is believed to lead to drastic changes in the delivery of stormwater to the stream. Quantitative evidence of connectivity is therefore needed if the concept is to serve as a diagnostic tool for hydrologic behaviours. Recent publications advocate that geostatistical connectivity is a universal measure as it transcends catchment idiosyncracies and allows for the detection of transitions and thresholds in flow processes. Yet, the geostatistical framework failed to reflect threshold change in runoff response in a temperate humid forested catchment (Mont St-Hilaire, Quebec). In this study based on a forested catchment from the Canadian Shield (St-Hippolyte, Quebec), we use three types of hydrological data analysis in searching for evidence of connectivity: (1) statistical classification techniques applied to meteorological records and storm hydrographs; (2) end-member mixing computations performed on stream and source areas geochemistry; and (3) catchment-wide multiple-depths soil moisture data subjected to pattern analysis. These methods correspond respectively to black, grey and white-box approaches towards understanding connectivity. Since the methods can be discriminated by accessibility, physical basis, robustness and spatial discretization, results obtained are compared to assess catchment behavior and prediction uncertainty. The black-box approach reveals that catchment responses, labeled as low/high magnitude and slow/quick timing, can be predicted from meteorological thresholds. It yields indirect evidence of connectivity by suggesting that a relationship between response types and antecedent conditions can be found if assumed nonlinear. The grey-box approach is helpful in identifying time-variable contributing sources to streamflow. Intermediate discharge levels are fed by an enhanced near-surface riparian-stream connection, while both riparian and hillslope areas produce overland flow when

  18. Parameterization of a Hydrological Model for a Large, Ungauged Urban Catchment

    OpenAIRE

    Gerald Krebs; Teemu Kokkonen; Heikki Setälä; Harri Koivusalo

    2016-01-01

    Urbanization leads to the replacement of natural areas by impervious surfaces and affects the catchment hydrological cycle with adverse environmental impacts. Low impact development tools (LID) that mimic hydrological processes of natural areas have been developed and applied to mitigate these impacts. Hydrological simulations are one possibility to evaluate the LID performance but the associated small-scale processes require a highly spatially distributed and explicit modeling approach. Howe...

  19. 10Be-derived denudation rates from the Burdekin catchment: The largest contributor of sediment to the Great Barrier Reef

    Science.gov (United States)

    Croke, Jacky; Bartley, Rebecca; Chappell, John; Austin, Jenet M.; Fifield, Keith; Tims, Stephen G.; Thompson, Chris J.; Furuichi, Takahisa

    2015-07-01

    Terrestrial cosmogenic nuclides (TCNs) such as Beryllium-10 (10Be) are now routinely used to reconstruct erosional rates over tens of thousands of years at increasingly large basin scales (> 100,000 km2). In Australia, however, the approach and its assumptions have not been systematically tested within a single, large drainage basin. This study measures 10Be concentrations in river sediments from the Burdekin catchment, one of Australia's largest coastal catchments, to determine long-term (> 10,000 years), time-integrated rates of sediment generation and denudation. A nested-sampling design was used to test for effects of increasing catchment scale on nuclide concentrations with upstream catchment areas ranging from 4 to 130,000 km2. Beryllium-10 concentrations in sediment samples collected from the upstream headwater tributaries and mid-stream locations range from 1.8 to 2.89 × 105 atoms g- 1 and data confirm that nuclide concentrations are well and rapidly mixed downstream. Sediment from the same tributaries consistently yielded 10Be concentrations in the range of their upstream samples. Overall, no decrease in 10Be concentrations can be observed at the range of catchment scales measured here. The mean denudation rate for all river sediment samples throughout the Fanning subcatchment (1100 km2) is 18.47 m Ma- 1, which compares with the estimate at the end of the Burdekin catchment (130,000 km2) of 16.22 m Ma- 1. Nuclide concentrations in the lower gradient western and southern catchments show a higher degree of variability, and several complications emerged as a result of the contrasting geomorphic processes and settings. This study confirms the ability of TCNs to determine long-term denudation rates in Australia and highlights some important considerations in the model assumptions that may affect the accuracy of limited sampling in large, low-gradient catchments with long storage times.

  20. Prioritization of catchments based on soil erosion using remote sensing and GIS.

    Science.gov (United States)

    Khadse, Gajanan K; Vijay, Ritesh; Labhasetwar, Pawan K

    2015-06-01

    Water and soil are the most essential natural resources for socioeconomic development and sustenance of life. A study of soil and water dynamics at a watershed level facilitates a scientific approach towards their conservation and management. Remote sensing and Geographic Information System are tools that help to plan and manage natural resources on watershed basis. Studies were conducted for the formulation of catchment area treatment plan based on watershed prioritization with soil erosion studies using remote sensing techniques, corroborated with Geographic Information System (GIS), secondary data and ground truth information. Estimation of runoff and sediment yield is necessary in prioritization of catchment for the design of soil conservation structures and for identifying the critical erosion-prone areas of a catchment for implementation of best management plan with limited resources. The Universal Soil Loss Equation, Sediment Yield Determination and silt yield index methods are used for runoff and soil loss estimation for prioritization of the catchments. On the basis of soil erosion classes, the watersheds were grouped into very high, high, moderate and low priorities. High-priority watersheds need immediate attention for soil and water conservation, whereas low-priority watershed having good vegetative cover and low silt yield index may not need immediate attention for such treatments.

  1. Innovative framework to simulate the fate and transport of nonconservative constituents in urban combined sewer catchments

    Science.gov (United States)

    Morales, V. M.; Quijano, J. C.; Schmidt, A.; Garcia, M. H.

    2016-11-01

    We have developed a probabilistic model to simulate the fate and transport of nonconservative constituents in urban watersheds. The approach implemented here extends previous studies that rely on the geomorphological instantaneous unit hydrograph concept to include nonconservative constituents. This is implemented with a factor χ that affects the transfer functions and therefore accounts for the loss (gain) of mass associated with the constituent as it travels through the watershed. Using this framework, we developed an analytical solution for the dynamics of dissolved oxygen (DO) and biochemical oxygen demand (BOD) in urban networks based on the Streeter and Phelps model. This model breaks down the catchment into a discreet number of possible flow paths through the system, requiring less data and implementation effort than well-established deterministic models. Application of the model to one sewer catchment in the Chicago area with available BOD information proved its ability to predict the BOD concentration observed in the measurements. In addition, comparison of the model with a calibrated Storm Water Management Model (SWMM) of another sewer catchment from the Chicago area showed that the model predicted the BOD concentration as well as the widely accepted SWMM. The developed model proved to be a suitable alternative to simulate the fate and transport of constituents in urban catchments with limited and uncertain input data.

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    This is the first attempt to budget average current annual carbon (C) and associated greenhouse gas (GHG) exchanges and transfers in a subarctic landscape, the Lake Torneträsk catchment in northern Sweden. This is a heterogeneous area consisting of almost 4000km2 of mixed heath, birch and pine fo...... be compared with the carbon emissions of less than 200 people who live permanently in the catchment, although this comparison disregards substantial emissions from the non-Swedish tourism and transportation activities....... 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......This is the first attempt to budget average current annual carbon (C) and associated greenhouse gas (GHG) exchanges and transfers in a subarctic landscape, the Lake Torneträsk catchment in northern Sweden. This is a heterogeneous area consisting of almost 4000km2 of mixed heath, birch and pine...

  3. Phosphorus and dissolved organic carbon export during peak flow periods in three small homogenous catchments in eastern Germany

    Science.gov (United States)

    Benning, R.; Schwärzel, K.; Feger, K. H.

    2012-04-01

    Regional climate change scenarios for Central Europe predict both an overall increase in temperature and alterations in annual precipitation regimes. For large parts of Central Europe, climate change is expected to result in an increase in winter precipitation and a decrease in summer precipitation. In addition, an increase in extreme conditions, such as heat waves, prolonged drought periods, and heavy rainfall events are predicted. This research examines the potential impacts of increased heavy rainfall events on matter export from small catchment areas, and how different vegetation cover and land management options effects these exports. In order to evaluate the export of matter from different land-use types in the Eastern Ore Mountains (Saxony, NE Germany, 50° 48'18.06" North, 13° 36'24.54" East), study sites were established in three small catchments with homogeneous land-use. These study areas are each sub-catchments of the Ammelsdorf catchment, which provides inflow to the Lehnmühle reservoir (a major water supply for the city of Dresden). Each sub catchment represents one of the three main land-use types in the catchment area of the reservoir: crops (winter oilseed rape, winter wheat), grasslands, and forests (primarily spruce). Since November 2009 the discharge from these sub catchments has been continuously measured and water quality was analyzed on a weekly basis. During peak flow events, discharge was collected using automatic water samplers, which allowed for high temporal resolution analysis of matter export during these periods to be made. During the 2010 and 2011 hydrological years, several heavy rainfall events occurred which have been evaluated. During a 110-hour long precipitation event (P = 170 mm) between 37 and 81 water samples per sub catchment were collected and analyzed. The resulting export of dissolved phosphorus (ortho-PO4-) and dissolved organic carbon (DOC) from the sub catchments during this event is provided in the results. In

  4. Hydrogeochemical signatures of catchment evolution - the role of calcium and sulphate release in the constructed Hühnerwasser ("Chicken Creek") catchment

    Science.gov (United States)

    Pohle, Ina; Hu, Yuzhu; Schaaf, Wolfgang; Gerwin, Werner; Hinz, Christoph

    2016-04-01

    The constructed Hühnerwasser ("Chicken Creek") catchment is an ecohydrological system in an initial state of development. The catchment with an area of 6 ha was built up from quaternary sediments in the post-mining landscape of Lusatia in Eastern Germany and serves as a critical zone observatory for detecting ecosystem transition. The soil substrate is characterized as sands to loamy sands with low carbonate contents but significant amounts of gypsum in the sediments of the catchment. The catchment undergoes a strong transition from an abiotic system in the initial years to a system with growing influence of biota. Concerning the hydrology, a regime shift from surface runoff to groundwater flow dominated processes is significant. It is of interest, whether the catchment transition is also reflected by hydrogeochemical indicators. We assume gypsum dissolution as dominant process at the catchment scale. In order to investigate the hydrogeochemical evolution of the catchment we analysed electric conductivity, calcium and sulphate concentrations and pH-values of biweekly composite samples from 2007-2013 of the atmospheric deposition, of runoff and soil water. The two observation points in the flowing water represent surface runoff and groundwater discharge respectively. Soil water has been analysed at four soil pits in three depths. The monitoring data were provided by the Research Platform Chicken Creek (https://www.tu-cottbus.de/projekte/en/oekosysteme/startseite.html). From the macroscopic data analysis we found an exponential decay of the electric conductivity, calcium and sulphate concentrations in the flowing waters and some of the soil pits. In the flowing water, the decrease slope of the electric conductivity and the calcium and sulphate concentrations is almost identical. The calcium / sulphate molar ratio as an indicator of gypsum dissolution is almost equal to one up to 2010, afterwards more calcium than sulphate is released. The pH-values in the flowing

  5. Predicting nutrient responses to mitigation at catchment to national scale: the UK research platform (Invited)

    Science.gov (United States)

    Johnes, P.

    2013-12-01

    Nutrient enrichment of waters from land-based and atmospheric sources presents a significant management challenge, requiring effective stakeholder engagement and policy development, properly underpinned by robust scientific evidence. The challenge is complex, raising significant questions about the specific sources, apportionment and pathways that determine nutrient enrichment and the key priorities for effective management and policy intervention. This paper presents outputs from 4 major UK research programmes: the Defra Demonstration Test Catchments programme (DTC), the Environment Agency's Catchment Sensitive Farming monitoring and evaluation programme (CSF), Natural Resources Wales Welsh Catchment Initiative (WCI) and the NERC Environmental Virtual Observatory programme (EVOp). Funded to meet this challenge, they are delivering new understanding of the rates and sources of pollutant fluxes from land to water, their impacts on ecosystem goods and services, and likely trends under future climate and land use change from field to national scale. DTC, a 12m investment by the UK Government, has set up long-term, high resolution research platforms equipped with novel telemetered sensor networks to monitor stream ecosystem responses to on-farm mitigation measures at a representative scale for catchment management. Ecosystem structural and functional responses and bulk hydrochemistry are also being monitored using standard protocols. CSF has set up long-term, enhanced monitoring in 8 priority catchments, with monthly monitoring in a further 72 English catchments and 6 Welsh priority catchments, to identify shifts in pollutant flux to waters resulting from mitigation measures in priority areas and farming sectors. CSF and WCI have contributed to >50 million of targeted farm improvements to date, representing a significant shift in farming practice. Each programme has generated detailed evidence on stream ecosystem responses to targeted mitigation. However, to provide

  6. Spatial patterns of catchment erosion on the Rio Grande Rift margin, Guadalupe Mountains, Texas and New Mexico

    Science.gov (United States)

    Tranel, L. M.; Schaefer, K.; Happel, A. A.; Rothschild, T. J.

    2016-12-01

    The escarpments of the Guadalupe Mountains serve as distinct landmarks to travelers across the southern US, but they also reflect the eastern boundary of the Rio Grande Rift. As the geoscience community continues to investigate how surface and mantle processes interact, the Guadalupe Mountains provide a valuable landscape to test if and how surface features capture mantle processes at the outer limits of extension. Although the rocks of the Guadalupe Mountains have been well studied for their relationship to petroleum sources and reservoirs, recent faulting and sediment production via erosion is less well understood. This study investigates the timing and spatial distribution of catchment erosion to investigate the spatial variability of erosional and tectonic influences. Analysis of topographic features suggests that eastern catchments are older features that formed prior to initiation of extension in the region. Therefore, we expect erosion rates to be slower in eastern catchments than the more recently exposed catchments to the west. Based on the typical evolution and propagation of normal faults, we also expect faster erosion rates in the center of the range than at the northern or southern ends. In this study, we use catchment averaged erosion rates from a combination of digital elevation models and cosmogenic radionuclides (CRN) to assess spatial variability across the range and along the western escarpment. CRN concentrations suggest erosion may be faster in catchments draining to the east. This could be related to a larger catchment area capturing more rainfall in ephermeral stream systems, and therefore providing more stream power to effectively erode bedrock. Volumetric analyses of catchments throughout the Guadalupe Mountains indicate that the greatest volume of sediment was eroded from catchments at the southern end of the range. The largest catchments drain east, however where faults are mapped, larger catchments formed near complex fault arrays to the

  7. Very long hillslope transport timescales determined from uranium-series isotopes in river sediments from a large, tectonically stable catchment

    Science.gov (United States)

    Suresh, P. O.; Dosseto, A.; Hesse, P. P.; Handley, H. K.

    2014-10-01

    catchment area of the Murrumbidgee River (Suresh et al., 2013), the current results indicate, for the first time, that sediments in the Murrumbidgee catchment are stored in hill slope for long time (∼200 kyr) before carried by the river. The long residence times of sediments indicate a low erosion rate from the catchment. The sediment transport timescales estimated are up to two orders of magnitude higher than those reported for tectonically active catchments in Iceland (Vigier et al., 2006) and in the Himalayas (Granet et al., 2007), indicating the influence of tectonism on catchment erosion.

  8. USLE-Based Assessment of Soil Erosion by Water in the Nyabarongo River Catchment, Rwanda.

    Science.gov (United States)

    Karamage, Fidele; Zhang, Chi; Kayiranga, Alphonse; Shao, Hua; Fang, Xia; Ndayisaba, Felix; Nahayo, Lamek; Mupenzi, Christophe; Tian, Guangjin

    2016-08-20

    Soil erosion has become a serious problem in recent decades due to unhalted trends of unsustainable land use practices. Assessment of soil erosion is a prominent tool in planning and conservation of soil and water resource ecosystems. The Universal Soil Loss Equation (USLE) was applied to Nyabarongo River Catchment that drains about 8413.75 km² (33%) of the total Rwanda coverage and a small part of the Southern Uganda (about 64.50 km²) using Geographic Information Systems (GIS) and Remote Sensing technologies. The estimated total annual actual soil loss was approximately estimated at 409 million tons with a mean erosion rate of 490 t·ha(-1)·y(-1) (i.e., 32.67 mm·y(-1)). The cropland that occupied 74.85% of the total catchment presented a mean erosion rate of 618 t·ha(-1)·y(-1) (i.e., 41.20 mm·y(-1)) and was responsible for 95.8% of total annual soil loss. Emergency soil erosion control is required with a priority accorded to cropland area of 173,244 ha, which is extremely exposed to actual soil erosion rate of 2222 t·ha(-1)·y(-1) (i.e., 148.13 mm·y(-1)) and contributed to 96.2% of the total extreme soil loss in the catchment. According to this study, terracing cultivation method could reduce the current erosion rate in cropland areas by about 78%. Therefore, the present study suggests the catchment management by constructing check dams, terracing, agroforestry and reforestation of highly exposed areas as suitable measures for erosion and water pollution control within the Nyabarongo River Catchment and in other regions facing the same problems.

  9. 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.

  10. Erosion studies at Lake Pyhäjärvi catchment (SW Finland)

    Science.gov (United States)

    Kirkkala, Teija; Ventelä, Anne-Mari; Tarvainen, Marjo; Jolma, Ari

    2014-05-01

    Lake Säkylän Pyhäjärvi is a large and shallow lake located in the centre of an intensive agricultural area in southwest Finland and it suffering from eutrophication. The nutrient load to Pyhäjärvi comes from diffuse agricultural sources in the catchment. The dominant land cover in the catchment area (22%) is made by cultivated fields, the rest comprising forests, peat lands and built-up areas. The soils of the Pyhäjärvi catchment are erosion sensitive clay, silt, till and peat. The suspended solid and nutrient transport of the main rivers flowing to the lake has been monitored since 1980's. Most part (over 70 %) of phosphorus load is particulate and erosion originated. In recent years the climate change has changed runoff patterns. In winter, mean air temperature is about -2.1 ºC and the catchment is also normally covered by snow in winter. However, in recent years there have been many years with higher winter time temperature and precipitation. In winter the fields are usually without vegetation cover and rainfalls increase erosion. There are already clear long term changes observed in runoff patterns and suspended solid load patterns. The erosion risk invention has been made to Yläneenjoki catchment in order to allocate erosion preventing measures. Sedimentation ponds, wetlands, buffer zones and filters have been used to catch the suspended solids from runoff but these methods are inadequate. In order to efficiently reduce nutrient load to the lake, the focus of the restoration measures should be in the soil, especially erosion preventing. Therefore more deep understanding and studying of erosion processes are needed. Runoff and erosion amounts and patterns should be measured in different types of fields should be done and combined to GIS-analysis.

  11. Spatio-temporal dynamics of sediment sources in a peri-urban Mediterranean catchment

    Science.gov (United States)

    Ferreira, Carla; Walsh, Rory; Blake, William; Kikuchi, Ryunosuke; Ferreira, António

    2017-04-01

    Sediment fluxes driven by hydrological processes lead to natural soil losses, but human activities, such as urbanization, influence hydrology and promote erosion, altering the landscape and sediment fluxes. In peri-urban areas, comprising a mixture of semi-natural and man-made land-uses, understanding sediment fluxes is still a research challenge. This study investigates spatial and temporal dynamics of fluvial sediments in a rapidly urbanizing catchment. Specific objectives are to understand the main sources of sediments relating to different types of urban land disturbance, and their variability driven by (i) weather, season and land-use changes through time, and (ii) sediment particle size. The study was carried out Ribeira dos Covões, a peri-urban catchment (6.2km2) in central Portugal. The climate is humid Mediterranean, with mean annual temperature and rainfall of 15˚ C and 892 mm, respectively. The geology comprises sandstone (56%), limestone (41%) and alluvial deposits (3%). The catchment has an average slope of 9˚ , but includes steep slopes of up to 46˚ . The land-use is a complex mosaic of woodland (56%), urban (40%) and agricultural (4%) land parcels, resulting from urbanization occurring progressively since 1973. Urbanization since 2010 has mainly comprised the building of a major road, covering 1% of the catchment area, and the ongoing construction of an enterprise park, occupying 5% of the catchment. This study uses a multi-proxy sediment fingerprinting approach, based on X-Ray Fluorescence (XRF) analyses to characterize the elemental geochemistry of sediments collected within the stream network after three storm events in 2012 and 2015. A range of statistical techniques, including hierarchical cluster analysis, was used to identify discriminant sediment properties and similarities between fine bed-sediment samples of tributaries and downstream sites. Quantification of sediment supply from upstream sub-catchments was undertaken using a Bayesian

  12. Inverse distributed hydrological modelling of alpine catchments

    Directory of Open Access Journals (Sweden)

    H. Kunstmann

    2005-12-01

    Full Text Available Even in physically based distributed hydrological models, various remaining parameters must be estimated for each sub-catchment. This can involve tremendous effort, especially when the number of sub-catchments is large and the applied hydrological model is computationally expensive. Automatic parameter estimation tools can significantly facilitate the calibration process. Hence, we combined the nonlinear parameter estimation tool PEST with the distributed hydrological model WaSiM. PEST is based on the Gauss-Marquardt-Levenberg method, a gradient-based nonlinear parameter estimation algorithm. WaSiM is a fully distributed hydrological model using physically based algorithms for most of the process descriptions.

    WaSiM was applied to the alpine/prealpine Ammer River catchment (southern Germany, 710 km2 in a 100×100 m2 horizontal resolution. The catchment is heterogeneous in terms of geology, pedology and land use and shows a complex orography (the difference of elevation is around 1600 m. Using the developed PEST-WaSiM interface, the hydrological model was calibrated by comparing simulated and observed runoff at eight gauges for the hydrologic year 1997 and validated for the hydrologic year 1993. For each sub-catchment four parameters had to be calibrated: the recession constants of direct runoff and interflow, the drainage density, and the hydraulic conductivity of the uppermost aquifer. Additionally, five snowmelt specific parameters were adjusted for the entire catchment. Altogether, 37 parameters had to be calibrated. Additional a priori information (e.g. from flood hydrograph analysis narrowed the parameter space of the solutions and improved the non-uniqueness of the fitted values. A reasonable quality of fit was achieved. Discrepancies between modelled and observed runoff were also due to the small number of meteorological stations and corresponding interpolation artefacts in the orographically complex

  13. Use of the mercury record in Red Tarn sediments to reveal air pollution history and the implications of catchment erosion.

    Science.gov (United States)

    Yang, Handong; Smyntek, Peter

    2014-11-01

    Red Tarn is a cirque lake with a small ratio of terrestrial area to lake area, surrounded by glacial edges with little soil in the catchment. A sediment core taken from the deepest area of the lake was (210)Pb dated and validated by (137)Cs and (241)Am stratigraphic records. The core was analysed for mercury (Hg) and other elements. The results show Hg pollution before the mid-19th century, and thereafter, a rapid increase in Hg pollution into modern time, followed by a decline in pollution since 1968-1970. This agrees well with the decline in UK Hg emissions since the Clear Air Act of 1968. The results suggest that the core has recorded Hg air pollution history, and it can be used to benchmark Hg changes in the sediments from other lakes in the region up to the late 1980s. However, increased (210)Pb fluxes after the late 1980s indicate enhanced catchment erosion, which has brought more legacy Hg in the catchment into the lake. As a consequence, since 2000, the Hg in the sediment record no longer reflects the atmospheric Hg deposition. The core shows how dominant Hg sources for the lake changed from atmospheric deposition to the catchment inputs, and demonstrates that contaminated catchment inputs have not only increased Hg fluxes to the lake sediments but have also increased Hg concentrations in the sediments.

  14. Significance of erosion-induced carbon fluxes in the carbon balance of a Mediterranean catchment

    Science.gov (United States)

    Nadeu, Elisabet; de Vente, Joris; Boix-Fayos, Carolina

    2014-05-01

    Large uncertainties surround our knowledge of the processes through which carbon (C) sequestration takes place in terrestrial ecosystems. Nevertheless, terrestrial ecosystems could be capturing up to one fourth of the CO2 that is emitted annually to the atmosphere from the burning of fossil fuels and land use changes. Soils are the third largest C reservoir in the C cycle, storing around 1500 Gt of C. Over the last decades, geomorphologists and soil scientists have claimed the role of soil erosion within the C cycle and its potential contribution to the terrestrial C sink. In order to assess the impact of soil erosion on the C cycle, however, an understanding and quantification of the impact of soil erosion on soil C stocks is needed. This implies quantifying lateral and vertical C fluxes associated to detachment, transport and deposition of soil and sediment at different spatial scales. As an example, we present a C budget for a mountainous catchment in south-eastern Spain for a 28 year study period during which the catchment underwent significant land use changes and hydrological correction works (i.e. check-dam construction and reforestations). We quantified lateral C fluxes induced by soil erosion processes and closed a soil/sediment C budget by combining field measurements and numerical modeling. In addition, correlation analysis was conducted between catchment properties (topographic, land use, lithology) and measured C deposition rates to understand the controlling factors on C yield (export) and C concentration in sediments. The results showed that the highest C yields (associated to high sediment yields) were found in subcatchments dominated by soft lithologies and high drainage densities. On the other hand, C concentration in deposited sediments was higher in areas dominated by forest cover, and presented high variability in those parts of the catchment with smoother slopes. Overall, we estimated that around 4000 Mg of C were mobilized from the catchment

  15. Hydrology and sediment yield calibration for the Barasona reservoir catchment (Spain) using SWAT

    Science.gov (United States)

    Palazón, Leticia; Navas, Ana

    2013-04-01

    Hydrological and soil erosion models, as Soil and Water Assessment Tool (SWAT), have become very useful tools and increasingly serve as vital components of integrated environmental assessments that provide information outside of direct field experiments and causal observation. The purpose of this study was to improve the calibration of SWAT model to use it in an alpine catchment as a simulator of processes related to water quality and soil erosion. SWAT is spatially semi-distributed, agro-hydrological model that operates on a daily time step (as a minimum) at basin scale. It is designed to predict the impact of management on water, sediment and agricultural chemical yields in ungaged catchments. SWAT provides physically based algorithms as an option to define many of the important components of the hydrologic cycle. The input requirements of the model are used to describe the climate, soil properties, topography, vegetation, and land management practices. SWAT analyzes small or large catchments by discretising into sub-basins, which are then further subdivided into hydrological response units (HRUs) with homogeneous land use, soil type and slope. SWAT model (SWAT2009) coupled with a GIS interface (ArcSWAT), was applied to the Barasona reservoir catchment located in the central Spanish Pyrenees. The 1509 km2 agro-forestry catchment presents a mountain type climate, an altitudinal range close to 3000 meters and a precipitation variation close to 1000 mm/km. The mountainous characteristics of the catchment, in addition to the scarcity of climate data in the region, require specific calibration for some processes. Snowfall and snowmelt are significant processes in the hydrologic regime of the area and were calibrated in a previous work. In this work some of the challenges of the catchment to model with SWAT which affected the hydrology and the sediment yield simulation were performed as improvement of the previous calibration. Two reservoirs, a karst system which

  16. Downward approach at the catchment scale or at the catchment set scale?

    Science.gov (United States)

    Perrin, C.; Andréassian, V.; Le Moine, N.

    2009-04-01

    The downward approach that learns from observations the main features of the catchment hydrological response has long been recognized as a way to develop hydrological models for the catchment scale (Klemes, 1983). In this approach, a link is made between rainfall inputs and flow outputs using the mathematical tools found the most efficient to reproduce catchment behaviour. This approach received recently more attention, as some limitations of the upward approach were identified (Sivapalan et al., 2003). However model structures developed with this downward approach at the catchment scale are often difficult to generalize, i.e. difficult to transpose to other catchments. Indeed they are often over-adapted to the specific features of the catchment on which they were developed. Generalization is a major problem in current hydrological modelling (Sivakumar, 2008). This is potentially a major drawback for the application of such models to the case of ungauged catchments. We argue that a better way to develop the structure of hydrological models following a downward approach is to place model development at the level of large set of catchments and not only at the level of a single catchment. This way of developing models will force them to be general, i.e. more transposable in space. They will capture the essential features of the rainfall-runoff transformation common between catchments. This way of developing models also gives the opportunity to analyse the spatial patterns of model failures, therefore providing more robust sources of explanations and more convincing ways to improve models. We do not believe that we could develop a single model that fit all conditions, but models developed with this approach are likely to be better starting points to get general models. Then we have to find ways to make them more appropriate to specific conditions without losing their generality. We will illustrate the advantages (and possible limitations) of this approach using

  17. Catchment Engineering: A New Paradigm in Water Management

    Science.gov (United States)

    Quinn, P. F.; Burke, S.; O'Donnell, G. M.; Wilkinson, M.; Jonczyk, J.; Barber, N.; Nicholson, A.; Proactive Team

    2011-12-01

    Recent catchment initiatives have highlighted the need for new holistic approaches to sustainable water management. Here, a catchment engineering approach seeks to describe catchment 'function' (or role) as the principal driver for evaluating how it should be managed in the future. Catchment engineering does not seek to re-establish a natural system but seeks to work with natural processes in order to engineer landscapes so that multiple benefits accrue. This approach involves quantifying and assessing catchment change and impacts but most importantly suggests an urgent and proactive agenda for future planning. In particular, an interventionist approach to managing hydrological flow pathways across scale is proposed. It is already accepted that future management will require a range of scientific expertise and full engagement with stakeholders, namely the general public and policy makers. This inclusive concept under a catchment engineering agenda forces any consortia to commit to actively changing and perturbing the catchment system and thus learn, in situ, how to manage the environment for collective benefits. The shared cost, the design, the implementation, the evaluation and any subsequent modifications should involve all relevant parties in the consortia. This joint ownership of a 'hands on' interventionist agenda to catchment change is at the core of catchment engineering. In this paper we show a range of catchment engineering projects from the UK that have addressed multi-disciplinary approaches to flooding, pollution and ecosystem management whilst maintaining economic food production. Local scale demonstration activities, led by local champions, have proven to be an effective means of encouraging wider uptake. Catchment engineering is a concept that relies on all relevant parties within a catchment to take responsibility for the water quantity and quality that arises from the catchment. Further, any holistic solution requires a bottom up, problem solving

  18. Land degradation trends in upper catchments and morphological developments of braided rivers in drylands: the case of a marginal graben of the Ethiopian Rift Valley

    Science.gov (United States)

    Demissie, Biadgilgn; Frankl, Amaury; Haile, Mitiku; Nyssen, Jan

    2014-05-01

    Braided rivers have received relatively little attention in research and development activities in drylands. However, they strongly impact agroecology and agricultural activities and thereby local livelihoods. The Raya Graben (3750 km² including the escarpment) is a marginal graben of the Ethiopian Rift Valley located in North Ethiopia. In order to study the dynamics of braided rivers and the relationship with biophysical controls, 20 representative catchments were selected, ranging between 15 and 311 km². First, the 2005 morphology (length, area) of the braided rivers was related to biophysical controls (vegetation cover, catchment area and slope gradient in the steep upper catchments and gradient in the graben bottom). Second, the changes in length of the braided rivers were related to vegetation cover changes in the upper catchments since 1972. Landsat imagery was used to calculate the Normalized Difference Vegetation Index (NDVI), and to map vegetation cover and the total length of the braided rivers. Spot CNES imagery available from Google Earth was used to identify the total area of the braided rivers in 2005. A linear regression analysis revealed that the length of braided rivers was positively related to the catchment area (R²=0.32, p<0.01), but insignificantly related to vegetation cover in the upper catchments. However, there is an indication that it is an important factor in the relationship calculated for 2005 (R²=0.2, p=0.064). Similarly, the area occupied by the braided rivers was related to NDVI (R²=0.24, p<0.05) and upper catchment area (R²=0.447, p<0.01). Slope gradient is not an important explanatory factor. This is related to the fact that slope gradients are steep (average of 38.1%) in all upper and gentle (average of 3.4%) in graben bottom catchments. The vegetation cover in the upper catchments shows a statistically insignificant increasing trend (R²=0.73, p=0.067) over the last 40 years, whereas length of rivers in the graben bottom

  19. Pilot implementation of WFD and creation of a tool for catchment management using SWAT: River Zglowiaczka Catchment, Poland

    Institute of Scientific and Technical Information of China (English)

    M.(S)MIETANKA; J.BRZOZOWSKI; D.(S)LIWI(N)SKI; K.SMARZY(N)SKA; Z.MIATKOWSKI; M.KALARUS

    2009-01-01

    Poland, like other EU countries, is obliged to implement the Water Framework Directive (2000/60/WE) by the end of 2015. The main objective of the Directive is to provide normative quality of all water resources (surface, underground and coastal sea waters). To reach this goal, reduction of water pollutant emission to the environment is needed. Our project focuses on pollution from agricultural sources which share in global pollution,which is high and growing. This is due to both intensification of agricultural activities and ignoring Agricultural Good Practice Code rules by farmers. In view of the above, this project is expected to provide analysis of selected catchments; especially those exposed to agricultural pollution risk, and propose adjustment strategies for new trends, still keeping in mind environ-merit protection.Our project concerns the area further called "sensitive area" (according to the rules of Regional Water Manage-ment Board in Warsaw). A part of Zglowiaczka fiver catchments in central Poland was defined as sensitive area (125.3 km2) where reduction of nitrogen and phosphorus run-off from agricultural land to water resources is especially needed. This is a typical agricultural district characterized by good soil quality (predominance of black swampy soil with deep and fertile humus layers). Due to this, it is the first and foremost high quality agricultural land, and almost forestless. The main topic of the research,with the use of the SWAT model, is to propose different means for reduction of migration of P and N to surface waters. Another problem is retention of water for actual and future irrigations. After model verification, calibration and validation, several climatic changes and reclamation strategies will be tested and simulated by the model to find the most effective and profitable solutions.The project focuses on supporting administration and self-governmental organization in the implementation of effective strategies of catchments

  20. Assessing Marginalized Communities in Mexico for Implementation of Rainwater Catchment Systems

    Directory of Open Access Journals (Sweden)

    Gerardo Sámano-Romero

    2016-04-01

    Full Text Available Mexico contains a high percentage of marginalized communities, as well as geographic areas with high annual precipitation (approximately 2000 mm. This study uses regional water access and precipitation data to determine municipalities that would most benefit from the installation of Domestic Rain Water Harvesting Systems (DRWHS. The main objective was to find a relationship between local conditions (marginalization, expected level of service, and precipitation and the physical components of DRWHS. First, monthly precipitation and the number of inhabitants per household were determined for each municipality. Catchment area and tank size were then calculated for a single dwelling by municipality using water demand, run-off coefficient, monthly precipitation, and number of inhabitants per household. In general, municipalities with very low access to municipal water and very high precipitation were found in the southern area of the country. A curve that estimates catchment area based on annual precipitation was developed using the selected municipalities, which produced an average catchment area of 113.3 m2 for a water demand of 100 L/capita/day. While any DRWHS must be designed specific to local conditions, this study has determined that a regional approximation can be used to select ideal communities for these systems, which can in turn facilitate national implementation.

  1. Prediction of dissolved reactive phosphorus losses from small agricultural catchments: calibration and validation of a parsimonious model

    Directory of Open Access Journals (Sweden)

    C. Hahn

    2013-10-01

    Full Text Available Eutrophication of surface waters due to diffuse phosphorus (P losses continues to be a severe water quality problem worldwide, causing the loss of ecosystem functions of the respective water bodies. Phosphorus in runoff often originates from a small fraction of a catchment only. Targeting mitigation measures to these critical source areas (CSAs is expected to be most efficient and cost-effective, but requires suitable tools. Here we investigated the capability of the parsimonious Rainfall-Runoff-Phosphorus (RRP model to identify CSAs in grassland-dominated catchments based on readily available soil and topographic data. After simultaneous calibration on runoff data from four small hilly catchments on the Swiss Plateau, the model was validated on a different catchment in the same region without further calibration. The RRP model adequately simulated the discharge and dissolved reactive P (DRP export from the validation catchment. Sensitivity analysis showed that the model predictions were robust with respect to the classification of soils into "poorly drained" and "well drained", based on the available soil map. Comparing spatial hydrological model predictions with field data from the validation catchment provided further evidence that the assumptions underlying the model are valid and that the model adequately accounts for the dominant P export processes in the target region. Thus, the parsimonious RRP model is a valuable tool that can be used to determine CSAs. Despite the considerable predictive uncertainty regarding the spatial extent of CSAs, the RRP can provide guidance for the implementation of mitigation measures. The model helps to identify those parts of a catchment where high DRP losses are expected or can be excluded with high confidence. Legacy P