北江上游水土流失与治理

Soil and Water Loss and Its Control in the Upper Reaches of Beijiang River

北江是广东省珠江水系的一大支流，包括韶关、清远两市所辖的12个县（市），面积2．94万km^2。本文首先论述了北江流域的水、土资源及其在社经生态结构中的地位，阐明了水土流失与生态平衡的动向，回顾本区水土流失的历史，反映当前水土流失现状；随后对水土流失诱因进行了分析，特别是对紫色页岩地区水土流失作了比较深刻的剖析；最后总结了水土流失综合治理的成效，在缓洪拦沙方面初步改善了山区河水暴涨暴落的水文特征，减少了汛期水量，同时增加了枯水期的流量，河流输沙量减少，变河床淤塞为下切，河床下降；保护土壤，提高土壤肥力显著，并取得了较大的社会效益和经济效益。

Beijiang river is a large tributary of Zhujiang water system in Guangdong province,including 12 counties (cities), with area 2. 94 × 10~4km^2. This paper dealt with soil and water resources of Beijiang watershed and its position in social, economic and ecological structures,described relationship of soil and water loss and eco-balance, reviewed history of soil and water loss in this area, analysed the situation and factors of soil and water loss, particularly for soil and water loss of purple rocky region, finally summarized comprehensive control benefit of soil and water loss. in the aspects of sediment reduction and flood retention, improved the hydrological feature of river water in the amountaious area, reduced the discharge in the flood period,increased the discharge in the low water period, reduced the sediment dischareg of river, dropped the riyer bed, improved soil fertility, obtained remarkable benefits of society and economy.