狮泉河盆地风沙灾害成因及其防治

Cause of wind-blown sand disaster in Shiquanhe Basin and its control

高寒干旱的气候、强劲的风力和富含易蚀物质的地表条件，孕育了狮泉河盆地剧烈的风沙灾害。狮泉河盆地风沙灾害治理工程由砾石沙障、防护林带、人工草地和灌溉工程组成。根据砾石沙障和林带防风阻沙效果的风洞模拟实验，以及戈壁风沙流的现场测定，砾石沙障走向确定为351．1°（与盆地主害风向的夹角为77°），高度为1．2m，沙障间距为12日。防护林带与砾石沙障平行配置，选用当地适宜生长的班公柳为造林树种，采用疏透度为0．5-0．8的通风结构，林带间距为43．2m。平行沙障和林带的合理配置，可以将工程区的风力控制在起沙风速以下。砾石沙障和防护林带间建设人工草地。

Cold and arid climate, strong wind, and plenty of erodible material account for serious windblown sand disaster in the Shiquanhe Basin, northwest of Qinghai-Tibet Plateau. Gravel sand-barrier and tree shelterbelt serve as the main measures to control windblown sand, with artificial grasslands and irrigation systems also contributing. Based on wind tunnel experiments of the gravel sand-barrier and tree shelterbelt, and field measure for sand flux on a Gobi Desert surface, the barriers were installed with 1.2-m-tall and at an azimuth of 351.1°, forming an angle of 77° with respect to the prevailing wind direction in the basin. The spacing of the barriers equals to 12 times of its height. Tree sheherbelts are arranged parallel to the gravel sand barriers and separated by 43.2 m, with local Salix hangongensis the main species. The permeability of the shelterbelts is designed to be between 0. 5 and 0. 8. The multiple rows of rationally schemed gravel barriers and tree shelterbehs can reduce wind speed below the threshold value required to initiate sand movement. Artificial grasslands were established between the gravel sand barriers and tree shelterbelts.