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排土场植被覆盖度及地形变化对流域水土流失的影响

Influence of dump vegetation coverage and topographic changeson soil and water loss in drainage basin

  • 摘要: 煤矿区排土场的水土流失现象十分严重,盲目地进行植被重建会消耗大量资源,合理的植被覆盖度有助于指导矿区植被重建工作。基于水力侵蚀预测模型GeoWEPP,在野外调查结合遥感技术获取实测数据的基础上,以矿群为研究尺度探究了研究区排土场植被覆盖度变化对流域水土流失的影响规律并得出排土场植被覆盖度最佳范围。分析了锡林浩特矿群所在流域水土流失量增加的主要原因,在此基础上进一步模拟了地形格局变化下流域水土流失量的变化,研究了流域地形和地表植被覆盖类型变化对流域水土流失情况的影响效果;以10%的植被覆盖度为间隔、10%~90%覆盖度为区间,以50 a为模拟时长,分区域模拟分析矿群所在流域水土流失,并通过非线性均值变点法分析了生态效益最大化时的排土场植被覆盖度最佳范围。结果表明:① 地形变化是研究区水土流失量增加的主要原因,地形变化对水土流失量增加的影响远高于排土场植被重建的缓解效果;② 排土场边坡是发生水土流失的主要源点,仅仅进行排土场的植被重建难以较好地缓解水土流失状况,应该在地貌重塑的基础上重建排土场植被,以达到研究区生态环境优化的效益最大化;③ 水土流失归一化值随植被覆盖度的升高呈幂函数分布,经均值变点法计算得出锡林浩特矿群排土场的植被覆盖度最佳范围为40%~50%。

     

    Abstract: The phenomenon of soil erosion in coal mine dumps is very serious, and blindly rebuilding vegetation in this area will consume a lot of resources. Reasonable vegetation coverage settings will help guide the vegetation restoration in the mining area.Based on the hydraulic erosion prediction model GeoWEPP, on the basis of the field survey combined with remote sensing technology to obtain the measured data, the influence of the change of vegetation coverage of the dump site on the water and soil loss in the study area was explored with the mine group as the research scale, and the dump site was obtained. The optimum range of vegetation coverage was obtained too. The main reasons for the increase of soil and water loss in the basin where the Xilinhot mining group was located were analyzed. On this basis, the change of the water and soil loss in the basin under the change of the topographic pattern was further simulated, and the influence of the change of the basin topography and surface vegetation coverage on the water and soil loss of the basin was studied.Taking 10% vegetation coverage as the interval, 10%-90% coverage as the interval, and 50 years as the simulation 〖JP+2〗duration, the regional soil simulation was〖JP〗LMused to analyze the water and soil loss in the watershed where the mine group was located. On this basis, the non-linear mean change point method was used to analyze the vegetation coverage of the dump site when the ecological benefit was maximized. The results show that: ① Topographic change is the main reason for the increase in soil erosion in the study area. The impact of terrain change on the increase in soil erosion is much higher than the mitigation effect of the vegetation reconstruction in the dump site.② The slope of the dump site is the main source area for soil erosion. It is difficult to alleviate the soil erosion situation only by the vegetation reconstruction in this area. The vegetation reconstruction of the dump site should be carried out on the basis of landform remodeling to achieve the maximum benefits of the ecological environment optimization in this district. ③ The normalized value of soil and water loss is distributed as a power function with the increase of vegetation coverage. The optimal range of vegetation coverage of Xilinhot mining group dumps is calculated by the mean change point method to be 40%-50%. As well as the setting range of the vegetation coverage of the dump in the case of the smallest amount of water and soil loss in thewatershed.

     

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