The Research Of Response Between Land Use/Cover Change And Baseflow In Meijiang Basin Based On GIS

The Meijiang basin was regarded as the studied area in this research, and the land use/cover change have great influence on the baseflow in the basin because of human activities. Taking the influence of topography, soil, weather, climate and the land use/cover change into account, the response between the amount of baseflow and the land use/cover change was analyzed by spatially distributed eco-hydrologic model SWAT (Soil and Water Assessment Tools). The amount of baseflow in Meijiang basin was simulated by using the measured data of rainfall, discharge during 1986-1987, 1995-2000, and topography, other weather data. The model was calibrated and validated by tool software Bflow.exe. The three subbasins were selected from the upriver, middle river and downriver. The change of baseflow was analyzed based on the land use/cover change which will help to know disaster of flood in the basin and establish countermeasure of preventing or controlling flood, and provide science evidence for comeback of vegetation and water environment.But the relation between the land use/cover change and the amount of baseflow involved multi-influence of weather, hydrology, soil, land cover and human activities. The Meijiang basin is a large-scale area, so the spatially distributed eco-hydrologic model SWAT was adopted for considering the relation of between the land use/cover change and the amount of baseflow. The SWAT is a sequence time spatially distributed eco-hydrologic model, is suited for complex large-scale basin in different soil, land use and management. The model partition the basin into hydrological response units (HRUs). The process of hydrology character, transportation and conversion of pollution was simulated in the HRUs.The SWAT model was run under four different the land use/cover circumstance to simulate the baseflow in Meijiang basin, the results as follows:Firstly, the amount of baseflow will be steadier and more great in 1987(S1) than the amount of baseflow in 2000(S2). The change of baseflow between months in 1987 is gentler than in 2000Secondly, when the forest is the dominating vegetation in basin (S3), the amount of baseflow will increase in the 1-2 month, 6-12 months, and will be steady. The change of baseflow between months is not big. But when the sandlot is the dominating the land use/cover in basin and the forest is a few (S4), the amount of baseflow will reduce in most monhs. The well-kept forest vegetation in the upriver basin has great influence on the amount of baseflow. If the well-kept forest vegetation in the upriver basin was lopped, the amount of baseflow will reduce quickly in both rainy and dry season.