滇中地区小流域水土流失治理效应研究

Effect of Comprehensive Treatment on Soil Erosion in the Small Watershed in Central Yunnan Province

通过生物措施、工程措施和耕作措施对滇中地区典型小流域——王家箐进行综合治理，对治理前后气象、水文、水土流失资料进行观测分析。结果表明综合治理后，试验区径流系数从0．290降到0．06，侵蚀模数从294．28t／（hm^2·a）降到9．19t／（hm^2·a），水土流失治理效果显著。治理措施减少水土流失作用主要表现在三个方面：一是提高了降雨产流的最小雨量和最大30min雨强I20，降雨产流的最小雨量从2．9mm提高到4．5mm，最小I30从0．027mm／min提高到0．067mm／min，最小PI30从0．077mm·mm／min提高到0．300mm·mm／min。二是降低了径流的泥沙含量，治理后的泥沙含量减少65％。三是影响了产流过程，采取水保措施延长了汇流过程，推迟并削减洪峰。选治理前后P，I30相似的降雨，分析其洪水过程表明，治理后产流的洪峰流量和洪量比治理前减少84．2％～92．1％和81．6％～87．5％，涨水速率降低78．6％～91．4％，洪峰和雨峰的间隔时间延长1．5～2倍。

In order to control soil and water loss in the small Wangjia watershed in central Yunnan Province , engineering, biological and crop cultivation measures were implemented. The data of climate, hydrology and soil erosion were collected and analyzed. It is indicated that the measures are effective to reduce soil and water loss in the small watershed. After comprehensive measures, the runoff coefficient decreases from 0. 287 to 0. 006 and the rate of erosion decreases from 294.28 t/（hm^2· a） to 9.19 t/（hm^2· a）. The erosive minimum precipitation（P） increases from 2.9 mm to 4.5 mm,and the minimum rainfall intensity of 30 min（I30） increases from 0. 027 mm/min to 0. 067 mm/min, and the PI3o from 0. 077 mm · mm/min to 0. 300 mm · mm/min. The runoff suspended sediment concentration decreases 65% ,and the runoff procedure converged extends and the peak of runoff reduces. The similar precipitation （P） and rainfall intensity of 30 min（I30） before and after treaded are selected and compared. The result indicates that, after treatment the peak flow is 84.2% ～92.1% less than before, and the runoff is 81.6 % ～ 87.5 % less, and the ratio of rising flow is 78. 6 % ～ 91.4 % less, the time interval between the peak flow and the peak precipitation extends 1.5～2 times.