关井限采对民勤绿洲地下水漏斗和植被影响研究

民勤绿洲是西北内陆河流域地下水超采严重、地下水漏斗突显、生态环境恶化的典型区域,寻找有利于地下水漏斗抑制和生态修复的调控方式是地下水管理亟待解决的首要问题。基于2011—2012年观测数据,采用GIS和FEFLOW软件,构建民勤绿洲潜水非稳定流模型,模拟分析不同关井限采方案对地下水漏斗和植被的影响。结果表明:(1)缩减地下水开采量能有效减缓地下水位下降,修复地下水漏斗,改善生态环境;(2)减少单井抽水量和关闭一定数量机井相结合缩减地下水开采量的方式,对于修复区域地下水漏斗,抬升绿洲边缘地区地下水位,增加植被存活面积较为有效;(3)目前已实施的关井方法有利于防治绿洲荒漠化,而相同比例关井方法对于区域地下水漏斗修复效果更明显,生态环境和社会效益更佳。研究成果可为当地地下水调控和管理提供参考。

Study on impact of closing well and limiting exploitation on groundwater depression cone and vegetation of Minqin Oasis

Minqin Oasis is a typical region with serious over-exploitation of groundwater， obvious groundwater depression cone and deteriorated eco-environment within the inland river basins of the Northwest China， and then the primary problem urgently to be solved therein for the groundwater management is to find out a regulation mode that is favorable to restrict the groundwater depression cone and restore the ecology. Based on the observed data from 2011—2012， the unsteady flow model for the phreatic water under Minqin Oasis is established with GIS and FEFLOW software for simulatively analyzing the impacts from different schemes of closing well and limiting exploitation on the groundwater depression cone and vegetation. The result shows that: （1） reduction of the groundwater exploitation can effectively slow down the decline of groundwater table， restore groundwater depression cone and improve the eco-environment； （2） decreasing pumping output of a single well and closing a number of wells with the combination of reducing groundwater exploitation are effective for restoring the regional groundwater depression cone and raising the groundwater table at the edge area of the oasis and increasing the survival area of vegetation； （3） the method for closing well implemented at present is favorable for the control of oasis desertification， moreover， the restoring effect from the method with the same proportion is more obvious with much better eco-environment and social benefits.