基于GIS和USLE的九龙江流域土壤侵蚀量预测研究

Study on Predicting Soil Erosion in Jiulong River Watershed Based on GIS and USLE

探讨了GIS和USLE相结合预测南方中等尺度流域土壤侵蚀量、标识流域土壤侵蚀严重区域。运用GIS建立九龙江流域基础地理数据库,利用ARC/INFO的栅格数据空间分析功能,根据USLE土壤侵蚀预测模型对数据库进行图形运算,预测了九龙江流域的土壤侵蚀量。结果表明,流域的年均侵蚀模数为2 730.3 t/km^2,侵蚀强度属中度。占流域面积85.72％的区域土壤侵蚀强度在中度以下。这一区域对流域土壤侵蚀量的贡献率为58.26％,而流域41.74％的侵蚀泥沙来自于占流域面积14.28％的强度以上侵蚀区域。在流域侵蚀强度的空间分布上,8个子流域属中度侵蚀区,其中船场溪、花山溪和雁石溪三个子流域侵蚀强度较大;6个子流域属轻度侵蚀区,其中漳州平原的龙海和浦南两子流域侵蚀强度最弱。

Integrated Geographical Information System(GIS) with Universal Soil Loss Equation(USLE),soil loss was predicted and risk areas of soil erosion were identified in Jiulong river watershed. Reasonable methods were adopted to obtain R, LS , K , C, P factors value. Results showed annual average soil erosion amount was 2 730. 3 t/ km^2 and it was in the category of middle degree erosion. The serious eroded area(sediment yield is higher than 5 000 t/km^2) only occupied 14. 28% of area, but contributed 41. 74 % of sediments in the watershed , while no or slightly eroded area(sediment yield is lower than 5 000 t/km^2) was 85. 72% of area, but contributed 58. 26% of sediments. The annual average soil erosion was higher in Chuanchang river, Huashan river, and Yanshi river sub- watersheds. The annual average soil erosion was lower in Longhai and Punan segment in North river sub-water- sheds.