柴达木盆地西缘尕斯库勒湖流域地下水流数值模拟及地下水资源评价

Numerical Simulation of Groundwater Flow and Evaluation of Groundwater Resources in Gasikule Lake Basin,Western Margin of Qaidam Basin

尕斯库勒湖流域所属行政区茫崖市自建市以来尚未建设较大规模的集中供水水源,在以水定产、以水定城的城市发展构架下,评价流域地下水资源及开采潜力对城市发展至关重要。文章基于资料收集、动态长观、钻孔抽水试验等手段,采用断面径流量法结合流域尺度的数值模拟,评价了区内地下水天然资源量和允许开采量,并对地下水开采后对水文环境的影响进行了评估。结果表明:尕斯库勒湖流域地下水天然资源量为98.82×10^(4)m^(3)/d,允许开采量为23.5×10^(4)m^(3)/d,地下水资源开采系数<0.4,开采程度低;开采稳定后下游泉水减少10.89×10^(4)m^(3)/d,蒸发量减少12.88×10^(4)m^(3)/d,开采量和泉水及蒸发量减少之和相等,开采地下水间接袭夺了无效蒸发和部分泉水;下游湿地区降深≤0.5 m,湿地面积不产生退化;尕斯库勒湖入湖量减少2.53×10^(4)m^(3)/d,能维持湖泊及湿地周围生态环境的良性循环。

The Gasikule Lake Basin is located in Mangya City,an administrative region where large-scale centralized water source projects have not been constructed since its establishment as a city.Within the framework of basing municipal production and urban development on water resources,the evaluation of underground water resources and extraction potential is crucial.This article evaluates the natural groundwater resources and permissible extraction volume within the area,as well as assesses the impact of groundwater extraction on the hydrological environment.The assessment is based on data collection,dynamic observations,pumpingtests,andnumerical simulations at the basin scale,combining the cross-section radial flowmethod.The results indicate that the volume of natural groundwater resources in the Gasikule Lake Basin is 98.82×10^(4)m^(3)/d,with a permissible extraction volume of 23.5×10^(4)m^(3)/d.The underground water extraction coefficient is less than 0.4,signifying a low extraction level.Following stable extraction,downstreamspring water decreases by 10.89×10^(4)m^(3)/d,while evaporation volume decreases by 12.88×10^(4)m^(3)/d.The total extraction volume equals the sum of the reduced volume of spring water and reduced volume caused by evaporation.Indirectly,the extraction of groundwater depletes ineffective evaporation and a portion of spring water.The depth of wetland areas decreases by≤0.5 m,without degradation of wetland area.The inflow into the Gasikule Lake decreases by 2.53×10^(4)m^(3)/d,but it canmaintain a positive ecological cycle around the lake and wetlands.