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    京津水源区传统水土流失治理措施及水沙环境效应分析

    Traditional control measures of soil erosion and their environmental effects on flow and sediment in the water source area of Beijing and Tianjin

    • 摘要: 针对京津水源区传统水土流失治理指导思想和治理模式只注重治理区生态经济效益,忽视减沙同时大量减水加剧上下游用水矛盾的问题,以承德市丰宁县达袋沟小流域不同治理措施定位试验结果,结合典型治理区坡面措施调查,重点研究坡面治理措施的水沙环境效应。结果表明:坡耕地与人工草地的土壤侵蚀模数大大超过北方土石山区的容许土壤流失量;天然草地较乔木林和灌木林具有较高的年径流量和径流系数;传统鱼鳞坑整地造林和鱼鳞坑加竹节壕整地造林措施拦沙、减流效应显著;中度、轻度退化天然草地封育措施下阴坡、阳坡植被覆盖率年均可提高1.63%和1.08%;在水源区传统鱼鳞坑整地造林和鱼鳞坑加竹节壕整地造林措施应限制在局部水土流失严重区域,并应适度降低整地标准;大面积中度、轻度退化的天然草地可采用封育措施,既可实现有效拦沙、恢复植被,又可增加坡面径流。

       

      Abstract: The traditional guiding ideology and treatment on soil erosion control pay attention to ecological and economic benefits of the harnessing area,which will reduce the sediment yield. However, the reduction of sediment could lead to the decrease of water, which will aggravate the water contradiction between upstream and downstream in the water source areas of Beijing and Tianjin. Environmental effects of slope measures on water and sediment were studied by investigation and location experiment in Dadai Watershed locating in Fengning County, Chengde City. Results showed that the erosion modulus in slope farmland and artificial grassland substantially exceeded soil loss tolerance in rocky mountain areas of northern China. Natural meadow had higher annual runoff and runoff coefficient than arbor forests and shrub forests. Traditional fish-scale pits measures had significant effects on sediment trapping and reduction of water yield. For moderate and mild degraded grassland under the management of closing hills, the vegetation coverage could improve by 2.84% and 1.97% in shady slope and sunny slope per year. Some traditional measures like fish-scale pits should be limited in areas where occurred serious soil erosion,and their preparation standard should be degraded. Large areas of moderate and mild degraded grassland under the management of closing hills could not only reduce sediment yield,recover vegetation,but also increase runoff.

       

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