干旱区植被盖度增加对降水入渗补给地下水的影响——试验研究与数值模拟  

The impact of vegetation coverage increase on groundwater recharge in the arid regions of Northwest China:Experimental and numerical study

作　　者：尹立河[1] 王晓勇[1] 黄金廷[1] 马洪云[1] 张俊[1] 董佳秋[1] 贺帅军[1] 

机构地区：[1]中国地质调查局西安地质调查中心/中国地质调查局干旱-半干旱区地下水与生态重点实验室,陕西西安710054

出　　处：《地质通报》2015年第11期2066-2073,共8页Geological Bulletin of China

基　　金：国家自然科学基金项目(批准号:41472228);中国地质调查局项目(编号:1212010634204;12120113104100)

摘　　要：随着西北旱区生态恢复工程的实施,该区生态环境持续改善,植被盖度不断增加。但植被冠层截留与蒸腾耗水加剧了包气带水分的亏空程度,减小了降雨对地下水的补给。采用原位试验方法,分析了植被覆盖区和裸土区不同深度土壤水势的变化规律。结果表明,受蒸发和蒸腾的共同作用,植被覆盖区平均土壤水势（-74k Pa）远低于裸土区（-16k Pa）,且变化剧烈,土壤水以向上运动为主。而裸土区土壤水势高,变化小,40cm以下土壤水向下运移,因此可以持续补给地下水。采用Hydrus-1D软件进行了长序列土壤水数值模拟,定量分析了植被盖度增加与地下水补给的关系。数值模拟结果表明,在裸土条件下,降雨对地下水的补给量介于82~333mm/a之间,平均值为197mm/a,平均降水入渗补给系数为0.53。而在植被覆盖的情况下,地下水的补给量几乎为0。最后,从植被蒸腾耗水和冠层降水截留2个方面讨论了旱区植被盖度增加对降雨入渗补给地下水的影响,提出了旱区水与生态和谐发展的建议。With the implementation of ecological restoration projects in Northwest China, the eco-environment has been improved continually, accompanied by the increase of vegetation coverage. The water consumption by plants will make the soil water deficient severely and reduce the groundwater recharge. In this study, the soil matric potential at the depth was measured in the vegetated and bare soil lysimeters in situ. The results show that the thaw and frozen period in the two lysimeters is similar and has less effect on groundwater recharge. The soil matric potential in the vegetated lysimeter（-74 k Pa） is much lower than that（-16 k Pa） in the bare soil lysimeter with the coexistence of evaporation and transpiration. Soil water moves upward mainly in the vegetated lysimeter. In contrast, soil matric potential is high and soil water moves downward below 40 cm, and thus groundwater can be recharged continually.Long-term simulation was carried out using Hydrus-1d to identify the quantitative relation between vegetation coverage increase and groundwater recharge. The results indicate that groundwater recharge varied from 82mm/a to 333mm/a with the average of197mm/a and the average infiltration coefficient was 0.53 in bare soil area. While in vegetated area, groundwater recharge was almost zero. Finally, the impact of vegetation coverage increase on groundwater recharge is discussed with respect to plant transpiration and canopy interception, and suggestions on the harmonic development of water and ecology in arid zones are put forward.

关 键 词：旱区 植被 盖度增加 地下水 补给 

分 类 号：P641[天文地球—地质矿产勘探]