泾河典型流域水沙变化及其景观格局分析

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

以黄河中游泾河流域的3个子流域为研究对象,借助GIS和RS技术与基本的水沙数据,分析各子流域水沙变化特点与土地覆被空间格局特征。结果表明:流域北部的环江上游、合水川与汭河的径流量和输沙量以及土地覆被空间格局分布差异显著;30多年来环江上游的径流量增加了60%而输沙量却增加了1倍多,汭河的径流量减少了约40%而输沙量却减少到1/5,合水川的径流量基本保持不变而输沙量略有增加;环江上游只有6种土地覆被类型以低密度草地和半荒漠草地为主,汭河有9种土地覆被类型以林地、农田和高密度草地为主,合水川有7种土地覆被类型以林地和郁闭灌丛为主。

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.