Hydorological Processes Simulation Of Storm Event Of Middle Scale Forest Watersheds In The Three Gorges Reservior Area

This paper takes middle scale forest watershed, namely Tung-li river （the basin area is1158km2） in Chongqing, as the research object. Based on discriminating the response relationship between rainstorm and runoff, we apply PRSM_Storm model which has physical mechanism to simulate the process of rainstorm-runoff.With the help of Arcgis₉.3software, the author obtains the hydrological information and geographic data from the DEM of Tung-li river basin, and divides the watershed into21river networks and42hydrological response units （HRU）. Data collection in the field of soil condition, landuse type and soil erosion situation are based on field survey and literature reading. According to the actual rainfall data from Wenquan hydrometric station, the author selects typical precipitation for calibrating the PRSM_Storm model, and verifies the correct values of major parameters.The conclusions are as follows:1. By analyzing and processing the date of basin river networks, soil condition, landuse, and precipitation-runoff, this study has initially established the hydrological parametres database for Tung-li river watershed.2. After calibration, the average values of Nash uncertainty coefficients Dy is0.691, and the pass rate of flood forecasting is88%. The simulation accuracy is able to meet the requests for prediction and research of the flood in the basin.3. The duration of rainfall and early precipitation have a big influence on model accuracy. As for simulating rainstorm-runoff process which is of longer duration of rainfall （more than24h）, and has the previous week precipitation exceeding20mm, PRSM_Storm model can achieve high accuracy.