河口镇到龙门区间水土保持措施减沙水代价分析

水利水保措施的水沙效应评价方法是人们研究的热点之一。为了揭示水土保持和水利措施减少径流和泥沙综合特征的指标,提出了能明确反映水利、水保措施减少单位泥沙量时减少的径流量的减沙水代价(RRS)概念。RRS越大,减少单位泥沙同时减少的径流量越多,在措施减少相同径流量时,减少的泥沙量越小。对河口镇到龙门区间21条主要支流1970—1996年不同水利、水保措施的RRS分析表明,灌溉措施RRS远超出水保措施,梯田、造林、种草等坡面措施的RRS较为接近,坝地的RRS最小。随着流域输沙模数的增加,梯田、造林和种草等措施的RRS与坝地RRS差异变小。年均降水量与坝地RRS为显著负相关,而年均降水量与梯田、造林、种草的RRS显著正相关。

Water Costof Sediment Control of Soil and Water Conservation in Hekou and Longmen Section of Yellow River

Water cost of sediment control(ratio of detained runoff and sediment, RRS) is an indicator derived from runoff and sediment detained by soil and water conservation practices or other water resource projects.RRS plays an important role in discovering the effect of soil conservation practices on water resources.A larger RRS shows that some practices or branches can reduce more runoff when the same weight of sediment is detained.The RRS in 21 of branches in Hekou and Longmen section of the Yellow River was analyzed based on dataset of sediment delivery modules,average annual precipitation,runoff and sediment detained by conservation practices and irrigation from 1970 to 1996.Results show that RRS of irrigation is far more than that of soil and water conservation practices.RRSs of terrace,forest and grass are similar but more than that of dam land.With the increase of sediment delivery modules,the difference between RRS of terrace,forest,grass and RRS of dam land decreases.The positive correlations between average annual precipitation and RRS of terrace,forest and grass practices are evident respectively,but the correlation between average annual precipitation and RRS of dam land is negative evidently.