The Study On Groundwater Resources Evaluation And Water Supply Risk Of The Water Source In Yanming Lake

Yanminghu demonstration plot of conservation culture is located in the northern part of Zhongmou country,Zhengzhou city in Henan province.The groundwater resources there have been the major source of water supply for the industrial and agricultural production.In recent years,the groundwater withdrawal in Zhongmou country has been progressively increased with the rapid population growth,high-speed development of industry,and the sharp extension of local irrigation area.Meanwhile,the Jiaru River in the country is gradually becoming an ephemeral stream with serious pollution,which turns into a source of groundwater pollution instead of relieving the pressure on water use for industry and agriculture.The decreasing inflow from Yellow River year by year also aggravates current situation.In consideration of the long-term development of society and local economy and subjecting to the principle of economizing on water,it is urgent to construct a well field to solve the water shortage by finding new source of groundwater with strong exploitation potentiality.In combination with the project of hydrogeological investigation for proposed well field in Yanminghu demonstration plot of conservation culture in Henan Province which is undertaken by the Zhengzhou City Water Conservancy Construction Survey and Design Institute,we have collected the hydrogeological investigation data of study area,and synthetically analyzed local hydrogeological conditions.Based on these work,we constructed a numerical simulation model of groundwater flow(2010)and a prediction model of groundwater flow under the planned exploitation condition by using groundwater modeling software GMS and ModFlow2005.The simulation results showed that the recharge of shallow groundwater under existing conditions was 8717.60×104m3/a,the safe withdrawal rate of shallow groundwater and that of deep groundwater under the planned exploitation condition was up to 9980m3/d and 19800m3/d respectively.Withdrawal of groundwater from shallow aquifers was mainly composed of the lateral inflow from Yellow River,increasing amount of lateral inflow from boundary,decreasing amount of groundwater evaporation,lateral outflow from boundary and decreasing amount of groundwater leakage to the middle aquifers.Withdrawal of deep groundwater came primarily from groundwater storage,which would induce lateral inflow and groundwater leakage to middle aquifers.According to the above study,we also analyzed the urban water supply risk and qualitatively proposed corresponding strategies.For the purpose of effectively responding to some particular situations of urban water supply,we quantitatively evaluated the amount of groundwater that can be pumped from shallow aquifer was 1459.27×104m3/a and from the aquifer was 1059×104m3/a when meeting the situation of several consecutive dry years or cutoff of Yellow River on the basis of the groundwater flow model of well field.In order to guarantee the water quality of the well field,a groundwater flow and particle tracking model of the well field was developed based on the prediction model of groundwater flow.The retrograde tracing was used to determine the hydraulic capture zones after 100 days of continuous pumping and 1000 days of continuous pumping with a stable groundwater table of well field.Finally,the Yanminghu well field was divided into first-grade protection zone,two-grade protected area and prospective protected area.