نتایج جستجو برای: catchments

تعداد نتایج: 4452  

Journal: :Hydrology and Earth System Sciences 2011
Rita Ley Markus Casper Hugo Hellebrand Ralf Merz

Catchments show a wide range of response behaviour, even if they are adjacent. For many purposes it is necessary to characterise and classify them, e.g. for regionalisation, prediction in ungauged catchments, model parameterisation. In this study, we investigate hydrological similarity of catchments with respect to their response behaviour. We analyse more than 8200 event runoff coefficients (E...

2016
András Bárdossy Yingchun Huang Thorsten Wagener

Hydrological models are usually calibrated for selected catchments individually using specific performance criteria. This procedure assumes that the catchments show individual behavior. As a consequence, the transfer of model parameters to other ungauged catchments is problematic. In this paper, the possibility of transferring part of the model parameters was investigated. Three different conce...

2017
Pertti Ala-Aho Doerthe Tetzlaff James P. McNamara Hjalmar Laudon Chris Soulsby Pertti Ala-aho

Tracer-aided hydrological models are increasingly used to reveal fundamentals of runoff generation processes and water travel times in catchments. Modelling studies integrating stable water isotopes as tracers are mostly based in temperate and warm climates, leaving catchments with strong snow influences underrepresented in the literature. Such catchments are challenging, as the isotopic tracer...

2006
K. Kyllmar B. Ulén H. Johnsson

Within the Swedish Monitoring Programme for Agriculture, 27 small agricultural catchments were investigated for between 9 and 14 years (6 years for one catchment), starting in the late 1980s, to determine the impact of agricultural activities on discharge water. The catchments represent major variations in climate, soil types and farming in Sweden and hence long-term average load of total nitro...

Journal: :Environmental pollution 2008
Z Gagkas K V Heal N Stuart T R Nisbet

Streamwater was sampled at high flows from 14 catchments with different (0-78%) percentages of broadleaf woodland cover in acid-sensitive areas in the UK to investigate whether woodland cover affects streamwater acidification. Significant positive correlations were found between broadleaf woodland cover and streamwater NO3 and Al concentrations. Streamwater NO3 concentrations exceeded non-marin...

Journal: :Ecological applications : a publication of the Ecological Society of America 2007
David Bruce Lewis Nancy B Grimm

In urban catchments of arid central Arizona, we investigate how the export of mineral and organic nitrogen (N) in storm runoff is regulated by interactions between local landscape characteristics and broader scale storm features. First, we test whether N export is more a function of (1) processes that affect N concentration in runoff or (2) the propensity of the catchment to convey rainfall as ...

2001
A. Prechtel C. Alewell M. Armbruster J. Bittersohl J. M. Cullen C. D. Evans R. Helliwell J. Kopácek A. Marchetto E. Matzner H. Meesenburg F. Moldan K. Moritz J. Veselý

Following the decline in sulphur deposition in Europe, sulphate dynamics of catchments and the reversibility of anthropogenic acidification of soils and freshwaters became of major interest. Long-term trends in sulphate concentrations and fluxes in precipitation/throughfall and freshwaters of 20 European catchments were analysed to evaluate catchment response to decreasing sulphate deposition. ...

2002
R. B. Bradford

The volume and duration of groundwater discharge following extreme winter recharge events in permeable catchments can often be more disruptive than the peak discharge. An estimation procedure for annual maxima flood series in permeable catchments is extended to annual flood volumes for different durations. Growth factors for durations of 1 to 30 days and return periods of up to 250 years are de...

2015
Sally A. Entrekin Kelly O. Maloney Katherine E. Kapo Annika W. Walters Michelle A. Evans-White Kenneth M. Klemow James P. Meador

Multiple stressors threaten stream physical and biological quality, including elevated nutrients and other contaminants, riparian and in-stream habitat degradation and altered natural flow regime. Unconventional oil and gas (UOG) development is one emerging stressor that spans the U.S. UOG development could alter stream sedimentation, riparian extent and composition, in-stream flow, and water q...

2007
S. Dinesh

In this paper, the characterization of catchments extracted from multiscale digital elevation models (DEMs) is performed. First, the lifting scheme is employed to generate multiscale DEMs. The catchments extracted from the generated multiscale DEMs are then characterized based on their numbers. A power law relationship is derived between the number of extracted catchments and the kernel size. T...

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