泾河流域淤地坝拦沙对降雨的响应分析

The Soil-Saving Dam Retain Sand Respond to Rainfall in Jinghe River Basin

采用回归统计方法对泾河流域淤地坝拦沙对降雨的响应关系进行了分析。通过降雨—产洪产沙—淤地坝拦沙关系的定量研究,提出了不同年代淤地坝拦沙量与降雨因子的响应关系式及其阈值;从实用角度给出了淤地坝年拦沙量的预估公式;简析了淤地坝拦沙量与减蚀量的尺度关系。结果表明:泾河流域淤地坝年拦沙量大于阈值1000万t/a对应的降雨阈值分别为最大1日降雨量大于40 mm、汛期降雨量大于350 mm和年降雨量大于450 mm;黄河中游地区不同空间尺度流域的淤地坝拦沙量与减蚀量均呈正比关系。随着流域空间尺度(面积)的减小,淤地坝减蚀量占拦沙量的比重呈增大趋势。

The regressive and statistic analysis method is used to analyses the effect of soil-saving dam to check sediment upon the response relationship to the rainfall in the Jinghe River valley in this paper. The response relationship equation between the soil-saving dam checking sediments and rainfall factors in different years and the rainfall threshold are suggested through the quantitative studies of relationships of rainfall-flood sediment-yield-soil-saving dam in different years, whereby the prediction formula for the yearly sediment check by soil-saving dam is given as viewed from the practical application, and the spa- tial scale relationship between the sediment check by soil-saving dam and erosion reduction is briefly analyzed. The results indicate that when the yearly sediment check by soil-saving dam in the Jinhe River valley is larger than the threshold value of 10^7t/a, the response rainfall threshold values are 40 mm of the biggest rainfall in one day, over 350 mm of rainfall in the rainy season and over 450 mm of rainfall in a year respectively. Accordingly, the sediment check by soil-saving dam with different spatial scales in the Yellow River Valley in found to be in positive proportion with the amount of soil eroded. With a decrease in the valley spatial scale （area） , the percentage of soil erosion reduction by soil-saving dam in sediment check appears to have the increasing trend.