三川河流域减沙效益初步分析

Analysis of sediment-reduction effect on comprehensive improvement of Sanchuan River basin

三川河流域是黄河中游地区一条多沙粗沙河流。流域面积4161km^21955年开始治理,1983年列为全国重点治理区,1986年治理面积占水土流失面积的34.5％。据水文站观测,近10年输入黄河的泥沙较前20年减少58.8%。采用水保法分析,1975年治理度为12.7%,减沙10.8%;1982年治理度为16.9%,减少19.0%:19.86年减沙31.6％。30多年来,流域水土保持措施共拦沙10389万t,占同期实测输沙量的14.7％。文章指出,近20年来人类生产活动,每年约增加河流泥沙的6～8％,抵消了部分水土保持效益,应引起社会重视。

Soil erosion control in Sanchuan River basin started in 1955 and was put on the list of key areas of national soil conservation program in 1983. The controlled area accounted for 34.5% of total area eroded. Comparison of the records measured at hydrologic stations for the last 10 years with those for 20 years before shows reduction of sediment delivery by 58.8%, of rainfall only by 0.57% . Based on the analysis with the balance method the control ratio was 12.7% in 1975 and 16.9% in 1982, and the reductoin of sediment load was 10.8% in 1975,19.0% in 1982 and 31.6% in 1986- For 30 years of control work, 103.9 million tons of sediment have been blocked within the basin , or 14.7%of sediment delivery recorded in the same time. The paper reports that human activities have led to the increasement of sediment load by 6 - 8 % per year,which partly offset the benefits of soil conservation. This phenomenon should be paid much social attention to.