岷江上游流域土壤侵蚀风险评估

针对岷江上游流域侵蚀现状、特点,在拟定评价指标的基础上,运用GIS加权叠加分析法探究了岷江上游流域侵蚀风险,得出如下结论:(1)陡坡占61.20%,年均降雨量差异较大,土壤土质疏松绵软,地震影响强度高;(2)中度以上侵蚀风险比例为89.31%,土壤侵蚀形势严峻;(3)中度侵蚀风险区主要分布在水网附近,与土地利用类型以及人类生产生活密切相关;重度风险区主要分布在岷江上游流域的西部、西南部和南部周边地区,与"5·12"汶川特大地震密切相关;(4)汶川、理县为重度风险侵蚀关键治理区,黑水、茂县、松潘为中度侵蚀风险治理区。

Risk assessment of soil erosion in the upper reaches of Minjiang River

Acco rding to the curr ent situation and characteristics o f soil erosio n in t he upper reaches of Minjiang River, after deter2 mining the assessment index es, w e used the metho d o f Weig hted Superposit ion Analysis to ex plor e the ero sion risk. T he r esults are as follow s: ( 1) In t he upper r eaches of Minjiang River, steep slo pes make up 611 20% of the area; annual r ainfa ll v aries sig2 nificantly; the so il is loo se and soft; the impact o f earthquake is stro ng . ( 2) The r atio of moderate and above ero sion risk w as 891 31% in the study ar ea, indicating a serious so il ero sion situat ion. ( 3) T he moderate risk areas a re mainly distributed near the water netw or k, and ar e closely related to land use t ypes and human activit ies; the hig h risk areas ar e mainly distributed in the west, so uthw est and so ut h of the upper reaches of Minjiang River, and are clo sely co nnected w ith the Wenchuan Earthquake. ( 4) Wenchuan County and Lixian County ar e key manag ement r egions of hig h erosion risk, and H eishui County , Maox ian Count y, and Songpan Co unty a re manag ement reg ions of moderate er osion risk.