نتایج جستجو برای: catchments area

تعداد نتایج: 587685  

2008
H. A. de Wit

Controls of stream water NO3 in mountainous and forested catchments are not thoroughly understood. Longterm trends in stream water NO3 are positive, neutral and negative, often apparently independent of trends in N deposition. Here, time series of NO3 in four small acid-sensitive catchments in southern Norway were analysed in order to identify likely drivers of long-term changes in NO3. In two ...

2015
Jianjun Zhang Tingting Zhang Yongnan Lei Xiaoping Zhang Rui Li James M. Vose

The continuous ecological management of the Loess Plateau is known throughout the world for two strategies: the integrated soil conservation project that began in the 1970s, and the “Grain for Green” project that began in the 1990s. Six sub-catchments nested in the Beiluo River basin were selected to investigate streamflow regime variations during the two project periods. The annual streamflow ...

2006
Isaac J. Larsen Joel L. Pederson John C. Schmidt

As in many areas of high relief, debris flows are an important process linkage between hillslopes and the Green River in the canyons of the eastern Uinta Mountains, yet the physical conditions that lead to debris flow initiation are unknown. A recent episode of enhanced debris-flow and wildfire activity provided an opportunity to examine the geomorphic impact of fire and the processes by which ...

Journal: :Ecological applications : a publication of the Ecological Society of America 2006
Hans S Eikaas Angus R McIntosh

Large losses of habitat could be caused by land use change that disrupts the dispersal networks used by migratory species. We assessed the relative losses of habitat for diadromous fish (i.e., those migrating between sea and freshwater) due to physical barriers, degradation of migratory passage associated with catchment land use, and site-scale land use characteristics on the West Coast, South ...

2006
J. O. Skøien

In this paper catchments are conceptualised as linear space-time filters. Catchment area A is interpreted as the spatial support and the catchment response time T is interpreted as the temporal support of the runoff measurements. These two supports are related by T∼A which embodies the space-time connections of the rainfall-runoff process from a geostatistical perspective. To test the framework...

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...

2015
M. Staudinger M. Weiler J. Seibert

Meteorological droughts like those in summer 2003 or spring 2011 in Europe are expected to become more frequent in the future. Although the spatial extent of these drought events was large, not all regions were affected in the same way. Many catchments reacted strongly to the meteorological droughts showing low levels of streamflow and groundwater, while others hardly reacted. Also, the extent ...

Journal: :مرتع و آبخیزداری 0
کاظم نصرتی استادیار دانشکده علوم زمین، دانشگاه شهید بهشتی، ایران

the term hydrological drought is applied to represent low water levels in streams, reservoirs and lakes as well as a low groundwater level. base flow index (bfi) as one of low flow indices gives the ratio of base flow to total flow and investigates basin’s ability to store and release of water in drought periods. the objectives of this study were to determine bfi and to validate this index in d...

ژورنال: علوم آب و خاک 2019

Catchment prioritization in terms of natural disaster intensity as well as prevention and control practices plays a main role in the natural resources and watershed management. In this study, a total of 24 sub-catchments in the Zohreh-Jarrahi basin were prioritized according to their morphometric parameters and using the mixed model of TOPSIS-Multivariate regression. A total of 12 morphometric ...

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...

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