柳河上游水土保持措施在“940713”暴雨中的防洪减灾作用

Effect of Soil and Water Conservation Measures in Flood Prevention and Disaster Reduction in the Rainstorm of"940713" in the Upper Reaches of Liuhe River

柳河上游流域面积４２５７．４ｋｍ２，水土流失面积３７６６．７ｋｍ２，年平均侵蚀模数５０００～１００００ｔ／ｋｍ２。重点治理前，柳河上游水土流失非常严重，强烈的水土流失使柳河成为一条多泥沙河流，造成下游河段淤积严重。重点治理后，柳河上游现治理程度达６０．７％。１９９４年７月１３日柳河流域平均降雨量２５５．７ｍｍ，达到百生一遇暴雨标准。由于水土保持措施的作用，这次降雨所产生的洪峰、洪量尚不足２０年一遇标准。在这次降雨中，水土保持措施巨大的蓄水保土作用可减少直接经济损失５．７１亿元，减少的洪水灾害损失可达数十亿元。

With an area of 4257. 4 km2, the upper reaches of Liuhe River, has soil loss area of 3766.7km2, with annual average erosion modulus of 5000～10000 t/km2. Before key harnessment, the soil loss of Liuhe River was very serious. The severe soil loss turned Liuhe into a muddy river and cause severe siltation in the lower reaches. After key harnessment,the harnessment degree in upper Liuhe River reached 60. 7%. A rain took place in Liuhe River on July 13, 1994 with average rainfall of 255. 7mm, 100 year rainstorm standard. The flood peak and volume of this rain didn't reach those of the 20 year rainstorm because of the effect of soil and water conservation. During this rainstorm, the great effect of soil conservation and water retain reduced direct economic benefit loss of 571 million yuan and flood disaster loss of 1 billion yuan.