USING WATER EROSION PREDICTION PROJECT(WEPP) MODEL TO SIMULATE FIELD-OBSERVED RUNOFF AND EROSION IN THE LOESS PLATEAU, CHINA
WEPP model, as a process-based soil erosion prediction model, can spatio-temporally simulate soil erosion and sediment yield. The objectives of this paper were to evaluate the suitability of WEPP in simulating runoff and soil erosion including testing and calibrating WEPP model in the loess environment, setting up the database of WEPP input parameters and applying the calibrated model to assess the impacts of slope and three type management scenarios on runoff and erosion. By use of the long-term plot test data, the parameters were optimized to reduce the discrepancy between the measured value and the predicted and the relative error was used to validate the prediction of WEPP and quantify the Models performance. Sensitivity analysis of the model was carried out for the input parameters to assess the rationality of the model and examine the response of the WEPP model by eliminating the error aroused from input parameters.The results showed that the simulated runoff fluctuated with soil effective hydraulic conductivity but didnt change least with soil albedo, interrill erodobility, rill erodibility, critical shear, slope length and slope gradient. As for soil loss and sediment yield, they were insensitive to interrill erodibility and soil albedo. They reduced with the decrease of rill erodibility, the increase of critical shear and effective hydraulic conductivity. And the slope length and slope gradient multiplied which were same as soil loss and sediment yield. Initially, the model was calibrated using 4 plots data for the period 2001-2004 and subsequently its performance was evaluated by estimating yearly runoff and sediment yield using other 6 plots data 2001- 2004. WEPP can rationally predict erosive trend and reflect the soil loss and deposition of each point in the hillslope. How to change the simulated results with land use and slope respectively was studied in different scenario. The results show the runoff in fallow land, cropland and the grassland reduces unceasingly. And as for soil loss, cropland was the least, then fallow land and grassland. As for the cropland, the change of runoff is not evident with the increase of slope. However, the soil loss and sediment yield will increase sharply when the slope of the runoff plot rises gradually. The WEPP-recommended soil erosion parameters were unsuitable for loessial soil. It should be set up WEPP input parameters database according to the loess environmental factors by testing and calibrating the WEPP model to reduce all kinds of errors. To use the WEPP hillslope model on loessial soil and steep slope, it is necessary to replace tillage management for fallow not to dirturb the cropping land and increase the vegetation coverage in high erosion intensity of Loess Plateau.
WEPP model parameters soil loss the Loess Plateau
Wanli Shi Qinke Yang Wengen Liao Chong Li
Department of Water Environment, China Institute of Water Resources and Hydropower Research, Beijing Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource
国际会议
High-level International Forum on Water Resources and Hydropower(第一届国际水利水电高层论坛)
北京
英文
617-629
2008-10-17（万方平台首次上网日期，不代表论文的发表时间）