长江流域水土流失调控作用分析

Study on Effect of Water and Soil Loss Regulation in Changjiang River Basin

在对长江流域水土流失现状及基本特点分析的基础上，论述了以小流域为单元的山、水、田、林、路的水土保持综合治理调控技术与方法，分析了长江上游水土保持综合调控的成效。经过十多年的水土保持持续调控，长江上游水土流失面积由20世纪80年代中期的62．22万km^2减少到1999年的53．07万km^2，下降了14．7％，治理区水土流失强度下降了1～2个等级，治理区林草覆盖率由治理前的35％提高到56％，治理区小流域拦蓄量比治理前普遍提高了30％以上，径流系数普遍降低10％-20％，削减洪峰流量15％左右。治理区农业生产生活条件得到基本改善，有效解决了1000多万群众的温饱问题，小流域经济和县城经济得到了发展，促进了社会主义新农村的建设。

On the basis of analysing soil and water loss actualities and basic features of Yangtze River basin, the authors first discuss the method of integrated soil and water conservation which takes the mountains, water source, fields, forest lands and roads in a small watershed as one ensemble, then present the effect of this improvement in upper Yangtze River basin. Because of this improvement of controlling soil for more than ten years in upper Yangtze River basin, the soil loss area was decreased from 622 200 km^2 in the mid-term of 1980s to 530 700 km^2 in 1999. In soil conservation regions, the intensity of soil loss was decreased 1 - 2 degrees, vegetation-covered rate increased from 35 % to 56 %, holding-capacity in small watershed enhanced more than 30 %, runoff coefficient decreased 10% -20% and the peak flow cut about 15%. The agriculture produce and living condition in these regions have been improved, a population of over ten million is living in adequate food and warm clothing and will be better off, economy in small watershed and counties are developing and these have promoted the new countryside construction.