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Is located in the upper reaches of the Yangtze River Three Gorges region, abundant water resources, is one of the China's energy center of gravity. In recent years, due to the sloping land, especially the irrational use of topographic conditions, there are obvious seasonal drought, soil erosion, the Three Gorges region runoff of sediment yield and water balance studies, it is very important. In this study, Watershed Runoff and Sediment observations under different land use patterns (sloping land, paddy fields, woodlands, stone-faced terraces, ridge terraces) plot experiment, Indoor Soil Physical Properties experiment, meteorological data analysis and SWAT model (Soil and Water Assessment Tool ) simulation method of combining the use of SWAT Model Three Gorges Zhang Chong sediment yield of watersheds runoff, and the water balance in the different land use patterns to simulate the following conclusions: small watershed measured results show that: Zhang Jia Chong small watershed 7-8 month of runoff and sediment yield the largest amount of 7-August centralized April-October 56% of the total rainfall, runoff and sediment yield accounted for April-October 62% of the total runoff and sediment yield in the amount of more than 99% rainfall and runoff and sediment, runoff and sediment yield more concentrated rainfall more 7-8 months. SWAT model to simulate the sediment yield of watersheds and runoff, and the calibration of relevant parameters based on measured sediment yield runoff data. The simulation results show that: the watershed monthly production the flow simulation efficiency E ns 0.73, the decision of the simulation and observed values of the linear regression coefficient R 2 0.90; monthly basin sediment yield simulation efficiency of E-(ns) reached 0.75, the decision of the simulation and observed values of the linear regression coefficient R 2 0.97. Note the SWAT can Zhangjiashan the punch small watershed runoff of sediment yield effective analog. The plot experiment observations indicate that: (1) surface runoff: Slope> paddy fields> ridge terraced stone-faced terraced woodland, slope runoff, soil erosion, forest land can effectively reduce the area of the surface runoff; (2) leakage amount: paddy field> ridge terraced stone-faced terraces sloping woodland, woodland leakage minimum; (3) land use continuity of surface soil moisture changes show little change of soil moisture in the simulation of long-term water balance process can be approximated to zero; (4) evapotranspiration: woodland> stone-faced terraces ridge terraces sloping> paddy fields, was not significantly different, evapotranspiration is the largest expenditure items in the water balance. SWAT model to simulate small watershed land use patterns, surface runoff, seepage, evapotranspiration distribution characteristics, the results show that the analog the efficiency E ns is greater than 0.70, linear regression decided the coefficient R 2 is greater than 0.80, the SWAT on the the Small Watershed use of surface runoff, leakage of the root layer and evapotranspiration more effective simulation.
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