橡胶坝蓄水工程对城市浅层地下水环境影响的评价

Impact of rubber dam project on ground water environment

在查清浅层地下水含水层组合情况后,通过实测资料对比分析了南阳市白河第三橡胶坝蓄水前后地下水开采量、地下水动态变化规律、地下水降落漏斗演变趋势、地下水水质情况、环境地质现象等问题。指出蓄水前,地下水环境处于不断恶化的过程中;浅层地下水超采严重致使市中心城区缺水严重;地下水位持续下降,在白河南北形成了2个降落漏斗并不断扩大;水质恶化,局部地段出现地裂缝,膨胀土地区低层建筑物墙体开裂等。蓄水后,在库水范围内白河侧渗底渗量增大,增大了浅层地下水的补给量,地下水动储量增大,大大缓解了市中心城区的缺水现状;在地下水开采量不断增大的情况下,漏斗中心的地下水位回升,并趋于动平衡状态;除橡胶坝下游、白河左岸1000m及右岸600m等处外,漏斗内的其它部位水质变好,地下水环境明显得到改善。但同时地下水位上升使某些建筑物地下室进水及需对拟建建筑物深基坑降水,给工程建设带来了一些不利影响。

The groundwater table and water environment in Nanyang City before and after the impounding of rubber dam project is analyzed according to the observation data. It is found that before the impounding the groundwater table was descending rapidly and the extent of depression funnel increasing continuously. At the same time, water quality was deteriorated and serious ground cracking happened. After the impounding,the groundwater table tends to rising and the extent of the funnel become smaller due to the recharge of seepage water from reservoir. The increase of groundwater dynamic storage capacity in aquifer alleviates the intense lack of water supply in the center area of the City. The water quality in most area is improved. But at the same time, some unfavorable impacts emerge such as submergence happened to the basements of buildings and groundwater in foundation pits must be lowered during construction to avoid the submergence due to the rising of-groundwater table.