Analysis of Runoff and Sediment Variation and Landscape Pattern of Typical Watersheds in Jinghe Basin

3sub-watersheds in the north of Jinghe basin were selected as study areas.Based on the runoff and sediment data of 3 hydrological stations and the precipitation data,classified MODIS image data,all of these were analyzed runoff and sediment variation of watersheds and its land cover pattern.Results show that the visible difference of runoff yield and sediment yield and land cover pattern were found in the up of Huanjian,Heshuichuan and Ruihe.The runoff yield increased 60% but sediment yield increased double of the up of Huanjian,runoff yield decreased 40% but sediment yield decreased five times of the Ruihe,runoff yield had no change but sediment yield increased slightly of the Heshuichuan over 30 yeays.The up of Huanjiang only had 6 land-cover types and dominated by low density grassland and semi-desert grassland,9 land-cover types and dominated by forest,cropland and high density grassland of Ruihe,but 7 land-cover types and dominated by forest and closed shrub of Heshuichuan.