小湾电站建设过程中水土流失动态研究

Dynamic Monitoring of the Soil Erosion During the Construction of Xiaowan Hydropower Stations

通过在小湾电站布设侵蚀钉、样方定点观测等方法,对厂坝绿化区、施工场地区、存（弃）渣场区、厂内道路区、土石料场区进行水土流失动态监测,研究大型电站建设区内不同部位的水土流失的分异情况,对比分析了项目建设区原生地表、监测前、监测过程中以及水保防治措施实施后的水土流失变化。结果表明：堆渣类扰动是项目建设区各土壤扰动类型水土流失的主要破坏源,其水土流失破坏率高达48%;监测期项目建设区水土流失面积、水土流失量有逐年减小的趋势;存（弃）渣场年水土流失量最大,占年内土壤流失量的72.30%~83.30%;水土防治措施实施后,项目建设区比原生地表的年水土流失量均有不同程度的下降,各项目的土壤侵蚀已由本地的轻度为主变为微度,且各分区的土壤侵蚀强度非常接近容许值500 t/（km2·a）。

In this paper, the soil erosion during the construction of Xiaowan hydropower was monitoring dy- namically by using methods of eroding nail and fixed quadrats observation, the spatial variation of soil erosion in different area of green areas, construction areas, abandoned dreg sites, earth rockfill materials sites and roads during the construction of the hydropower station were analyzed, and the temporal different of soil erosion in the of primary surface of the construction area at three period of before the monitoring, during the monitoring and after bringing soil and water conservation measures were studied. The results showed that the abandoned dreg disturb- ance was the main soil disturbance types contributed for soil erosion soil loss amounts, which accounted for the 48% of the total erosion amounts. And the soil erosion load from abandoned dreg site was accounted for 72.30% to 83.30% of the year total soil loss amounts. The soil loss amounts showed a decreasing trend during the monito- ring period. Compared with primary surface, a decreased trend for soil erosion amounts were observed in all mo- nitoring areas after bringing soil and water conservation measures, the soil erosion levels in all monitoring areas decreased from slight to weak degrees, and the soil erosion modulus was close to the soil loss tolerance vale of 500 t/（ km2· a）.