نتایج جستجو برای: catchments area
تعداد نتایج: 587685 فیلتر نتایج به سال:
In the past few decades, the quantitative computation of surface roughness has received increasing attention due to its importance in numerical surface study. In this paper, concepts of mathematical morphology are employed to compute and characterize the surface roughness of catchments extracted from a simulated digital elevation model (DEM). Morphological smoothing is implemented on the simula...
The U.S. Geological Survey conducted an environmental assessment of 198 catchments in a 54,000-km area of central Colorado, much of which is on Federal land. The Colorado Mineral Belt, a northeast-trending zone of historical baseand precious-metal mining, cuts diagonally across the study area. The investigation was intended to test the hypothesis that degraded water and sediment quality are res...
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 ...
Geomorphometry of headwater catchments has been poorly reported in the Central-Eastern Pyrenees. This study presents a series of parameters obtained for Central-Eastern Pyrenean headwater catchments. The database consists of 3005 1and 655 2-order catchments. These catchments have been digitalised, identified, and attributed a value for each parameter. The parameters investigated are divided int...
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...
An approach for regional low flow frequency analysis is to use multiple regression techniques for obtaining relationships between low flows with specific return periods and catchments characteristics. In this paper, this method has been used. After single-site frequency analysis for 20 stream gauging stations, homogeneity test was performed. Regional relationships between low flows with return ...
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 ...
Design hydrographs are important for the design of hydraulic structures such as spillways and retention ponds. Due to the lack of the local data, engineers have to estimate design floods based on techniques which are able to predict runoff based on rainfall on a regional basis. In this study, Clark instantaneous unit hydrographs are used to predict design flood hydrographs for the selected catc...
In this study lake levels of Lake Tana are simulated at daily time step by solving the water balance for all inflow and outflow processes. Since nearly 62% of the Lake Tana basin area is ungauged a regionalisation procedure is applied to estimate lake inflows from ungauged catchments. The procedure combines automated multi-objective calibration of a simple conceptual model and multiple regressi...
An approach for regional low flow frequency analysis is to use multiple regression techniques for obtaining relationships between low flows with specific return periods and catchments characteristics. In this paper, this method has been used. After single-site frequency analysis for 20 stream gauging stations, homogeneity test was performed. Regional relationships between low flows with return ...
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