西藏日喀则地区水土流失危险度评价

Evaluation on danger degree of water and soil loss in Rikaze,Tibet

在分析影响西藏日喀则水土流失的自然因素和人为因素的基础上,从水土流失现状和驱动力两个方面选择了10个评价指标,建立了日喀则水土流失危险度综合评价模型并进行了评价。结果表明:南木林、谢通门、昂仁3县处于轻度危险状态,定日、萨迦、萨嘎、仲巴、聂拉木、岗巴、康马、日喀则8县处于中度危险度状态,其余的县市水土流失危险度指数值都比较大,处于重度危险状态,尤以定结县和拉孜县最为突出。通过危险度指数和现状强度指数的比较,南木林、昂仁、定日、仲巴、聂拉木、岗巴、日喀则、康马、亚东、定结、白朗的水土流失危险度指数高于水土流失强度现状指数,其水土流失程度可能将进一步加剧,其中昂仁、定日、仲巴、谢通门、岗巴、日喀则、康马、亚东很可能从目前的轻度水土流失区跃为中度水土流失区;而仁布、拉孜和吉隆的水土流失危险度指数低于水土流失现状强度指数,其水土流失程度将有所下降,但只有拉孜可能从中度水土流失区下降到轻度水土流失区。谢通门、萨迦、萨嘎、江孜的水土流失危险度指数和现状强度指数相近,因而在今后其变化可能较小。

Based on the analysis of natural and human factors effecting water and soil loss（WSL） in Rikaze,Tibet, 10 indices are selected by considering actuality and driven forces, synthesized evaluation model of WSL danger degree is built and an estimation is carried out. The evaluation result shows that a light danger degree situation exists in Nanmulin, Xietongmen and Angren; Dingri, Sajia, Saga, Zhongba, Nielamu, Gangba, Kangma and Rikaze county share a moderate danger degree; other counties take severe WSL, especially Dingjie and Lazi county. By comparing danger degree indices with actual intensity, a situation that danger degree indices of WSL higher than actual indices in Nanmulin, Angren, Dingri, Zhongba, Niemula, Gangba, Rikaze, Kangma, Yadong, Dingjie and Bailang. A trend of deteriorating WSL in these counties is discovered, and changes on WSL from the light to moderate are likely to become true in Angren, Dingri, Zhongba Xietongmen Gangba, Rikaze, Kangma and Yadong. Meanwhile, the WSL danger degree indices are lower than previous WSL indices in Rengbu, Lazi and Jilong, and a descending trend of WSL comes out, and Lazi is the only one shares the probability of changing from moderate WSL area to light. The danger degree indices of WSL in Sajia Saga and Jiangzi are close to actual WSL indices. Therefore, a slight variation of WSL exists in these counties.