Research On The Hydrological Response Of The Change Of The Protective Forest In Hongmenchuan Watershed Based On SWAT Model

Used distributed hydrological model——SWAT(Soil and Water Assesmsent Tool) which developed by United States Department of Agriculture, supported by Remote Sensing and Geographic Information System, the simulate research on the hydrological response in Hongmenchuan Watershed of north Beijing mountain area was carried out, meanwhile, according to the regional character of north Beijing mountain area, constructed protective forest system pattern, studied the hydrological response of forest vegetation.Based on meteorological and hydrological data of Hongmenchuan Watershed, combined with land-use map, soil type figure and DEM map, with the use of SWAT model, the hydrological process of Hongmenchuan Watershed has been simulated. This paper has taken sensitivity analysis module and automatic calibration module which provided by AVSWAT, calibrated the important parameters of the model rapidly and accurately, which made the model simulated runoff good, it showed the method has a preferable applicability in Hongmenchuan Watershed.SWAT model could simulate hydrological response such as runoff of different precipitation condition, this paper combined with precipitation data of 17 years from 1990 to 2006 of Hongmenchuan Watershed simulated the runoff of normal year, wet year and dry year respectively, then analyzed the influence of precipitation on hydrological changes. According to the characteristics of dry season and flood season of precipitution in year, analyzed hydrological response of different precipitation condition of various moons.In order to master the hydrological function of different underlying surface situation in Hongmenchuan Watershed, seeking the best forest vegetation cover of the Watershed, and provide reference for protecting forest arrangement, this paper designed 5 scenario change situations totally. Simulated the runoff of the 5 scenarios by SWAT model respectively. The results showed that: with the increase of forest vegetation cover rate, runoff decreased, forest vegetation has a obvious reducing eco-hydrological function.