赣江流域水土保持生态建设减水减沙效益评价

利用赣江流域1956-2008年年降雨量和赣江控制站外洲水文站年径流量和年输沙量资料，采用水文分析法计算赣江流域近30a水土保持生态建设的减水减沙效益。结果表明，赣江流域治理后期1984-2008年水土保持生态建设年均减沙量为5.70×10⁶t，年均减沙效率为48.57%。随着水土保持措施的生效，减沙率有逐年上升而后稳定的趋势，2008年减沙率达80.54%；赣江流域水土保持生态建设对流域年径流总量减少不明显，后期径流量反而会有所增加。水土保持生态建设能增加流域土壤入渗，减少地表径流，削减洪峰流量，延长汇流时间，起到防洪减灾效果。

Effects of Runoff and Sediment Reductions by Soil and Water Conservation Measures in Uanjiang Watershed

By using hydrological method,the data of annual rainfall,runoff and sediment from 1956 to 2008 were used to calculate the effects of runoff and sediment reductions by soil and water conservation measures in Uanjiang watershed during the recent 30 years.Results show that the average annual sediment into the Poyang Lake was reduced by 5.7 million tons and sediment reduction was about 48.57%after taking soil and water conservation measures.With the role of the soil and water conservation measures played,sediment reduction rate had increased year by year and then held a stable trend;and sediment reduction rate was 80.54% in 2008.The decrease in annual total runoff was not obvious,while runoff at late stage was increasing.Ecological construction by soil and water conservation could increase the watershed rainfall infiltration,reduce surface runoff,reduce peak flows,extend the convergence time,and play an important role in flood control and disaster mitigation.