SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Watershed discretization based on multiple factors and its application in the Chinese Loess Plateau 
Authors:Xu, Y.D., B.J. Fu, C.S. He and G.Y. Gao 
Journal:Hydrology and Earth System Sciences 
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Broad Application Category:hydrologic only 
Primary Application Category:HRU and/or subwatershed delineation effects 
Secondary Application Category:hydrologic assessment 
Watershed Description:1334 km^2 Ansai in the Loess Plateau region in north central China 
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Abstract:The spatial discretization of watersheds is an indispensable procedure for representing landscape variations in eco-hydrological research, representing the contrast between reality and data-supported models. When discretizing a watershed, it is important to construct a scheme of a moderate number of discretized factors while adequately considering the actual eco-hydrological processes, especially in regions with unique eco-hydrological features and intense human activities. Because of their special lithological and pedologic characteristics and widespread man-made vegetation, discretization of watersheds in the Loess Plateau in Northern China is a challenge. In order to simulate the rainfall-runoff process, a watershed in the Loess Plateau, referred as Ansai, was spatially discretized into new units called land type units. These land type units were delineated under a scheme of factors including land use, vegetation condition, soil type and slope. Instead of using units delineated by overlaying land use and soil maps, the land type units were used in the Soil and Water Assessment Tool (SWAT). Curve numbers were assigned and adjusted to simulate runoff, using the US Natural Resources Conservation Service (NRCS) curve number method. The results of the runoff simulation better matched actual observations. Compared to the results that used the original units, the coefficient of determination (R2) and the Nash-Sutcliffe coefficient (ENS) for monthly flow simulation increased from 0.655–0.713 and 0.271–0.550 to 0.733–0.745 and 0.649– 0.703, respectively. This method of delineating into land type units is an easy operation and suitable approach for ecohydrological studies in the Chinese Loess Plateau and other similar regions. It can be further applied in soil erosion simulation and the eco-hydrological assessment of re-vegetation.