基于差分GPS技术的淤地坝泥沙淤积量估算

淤地坝是黄土高原水土流失治理中的一项重要措施。但是早期建设的淤地坝缺乏监测资料，对现已淤满坝地拦截泥沙量的估算成为当前研究中的一个难点问题。该文选取延安宝塔区羊圈沟小流域1979年修建的淤地坝为研究对象，采用高精度差分GPS技术，测量坝地淤积面平均高程和淤地面积，结合1977年1︰10 000地形图，建立高程—面积/淤积量曲线，得出羊圈沟淤地坝淤积泥沙方量为155 849.2 m3，并通过计算得到建坝至淤满期内（1979－2004年）年平均土壤侵蚀模数4 052.1 t·km-2·a-1，属于中度侵蚀。差分GPS技术的应用为准确估算淤地坝泥沙淤积量提供了技术支撑，可以弥补历史上侵蚀产沙数据，而且对定量评价水土流失及其治理效益提供了依据。

Estimation of sediment volume trapped by check-dam based on differential GPS technique

The check-dam is an important measure for controlling soil and water loss in Loess Plateau. However, because of the lack of monitoring data on early built check-dam, the estimation for sediment volume trapped by full-filled check-dam becomes a difficulty issue. A check-dam built in Yangjuangou watershed in 1979 was taken as a case, which located in Baota district, Yan’an city, Shaanxi Province. By using high precision differential GPS technique, the average elevation of sediment surface and the silt area were measured. Based on 1997’s topographic map at scale 1︰10 000, the elevation-area/ sediment mass curve was obtained. The results indicated that the volume of dam-trapped sediment was 155 849.2 m3 (1979-2004) in Yangjuangou watershed, and calculated soil erosion modulus was 4 052.1 t·km-2·a-1, which belonged to the degree of moderate erosion. Application of differential GPS technique for estimating sediment volume provides technical support for accurate estimate of sediment volume trapped by check-dam, which can make up the data of erosion and sediment during history, and present the evidence on quantitative evaluation of soil and water loss and its controlling benefits.