Three-dimensional Geological Modeling And Numerical Simulation Of Groundwater Flow In Huangqihai Basin Of Inner Mongolia

The watershed in Wulanchabu City,Inner Mongolia Autonomous Region,is characterized by typical inland river basins,and local socio-economic development and water resources demand are seriously dependent on groundwater.The proportion of groundwater supply to total water supply in Wulanchabu City has increased from 89.8%in 2008 to 94.4%in 2013(according to the Ulan Qab Water Resources Bulletin of 2013),which has caused the groundwater in some areas to be seriously super Mining status.In order to ensure the sustainable exploitation of local groundwater resources and thus promote the sustainable development of the local economy and the orderly implementation of ecological civilization,it is necessary to analyze and study the dynamic changes of groundwater in the city of Wulanchabu to provide a theoretical basis for the sustainable exploitation of groundwater.In this paper,the groundwater numerical simulation software GMS was used to establish a three-dimensional hydrogeological structural model of the Huangqihai Basin.Based on this,the groundwater numerical simulation model was established using the MODFLOW module.The revised model was used to simulate and predict the groundwater dynamics in the Huangqihai Basin under different mining scenarios,and reasonable suggestions were made for the sustainable exploitation of groundwater in the study area.The results show that the built-up groundwater numerical model after verification by GMS has a good overall fitting effect.The deterministic coefficient of groundwater observation water level and simulated water level reaches more than 90%,and the simulation degree is high.During the simulation period(April 2010-October 2016),the average annual recharge of groundwater was 10177.5x104m3/a,and the excretion was 10455.3x104m3/a.The amount of rainfall infiltration and lateral replenishment respectively accounted for the total recharge 77.2%and 16.4%,groundwater evaporation and groundwater extraction accounted for 63.8%and 36.2%of the excretion respectively.Using the identified model to predict the groundwater dynamics under different groundwater conditions in the Huangqihai Basin,the results show that the groundwater level in the Huangqihai Basin continues to decline with the increase in the amount of groundwater extracted,and the water depth in some areas exceeds 5m,seriously threatening the local area.ecosystem.Therefore,the development of a sustainable groundwater mining program is crucial to the protection of the local ecological environment.