Groundwater Resources Evaluation Of The Yingshuiqiao Wellfield In Zhongwei Of Ningxia

Zhongwei city is one of the most important cities along the Yellow river economic zone in Ningxia.However,in recent years,with the rapid development of social economy and population growth,coupled with the impact of urban planning,the original water source region are planned to be closed off,the domestic water for the city appears in a tense situation.In this paper,based on the full collection,analysis and study of previous geological and hydrogeological data and combined with the city planning of Zhongwei,the region of Yingshui bridge town which located in the west of the Zhongwei city is selected as a new water resource.14 production wells are designed,well group interference superposition analytical method is used to predict the variation of groundwater level under mining conditions,and water balance method and finite difference method are adopted to calculate groundwater resources.The recharge capacity of the water-bearing formation is evaluated,the level of assurance of water resources exploitation is further demonstrated.The results show that calculation by using water balance method,the recharge capacity of the water source is6.195×10~4m~3/d,the discharge is 6.213×10~4m~3/d,balance difference is-0.018×10~4m~3/d.Through the finite difference method,the recharge capacity of groundwater in the model area is 6.269×10~4m~3/d,the discharge is 6.439×10~4m~3/d,balance difference is-0.17×10~4m~3/d.Two kinds of evaluation results show slight negative balance which indicates that groundwater exploitation is guaranteed.In terms of water quality,the overall water quality in the phreatic water-bearing formation water is better,only individual holes exist iron,manganese,nitrate and nitrite overweight in different degrees.General boiler water is basically less boiler deposit,soft-hard scale quality,little sparkling semi-corrosive and non-corrosive water.Single well permissive yield of the 14 production wells which are arranged this time are limited to 3000 m~3/d,so we can submit to a centralized water supply sources with available resource of 42000m~3/d(Grade B)and mining evaluation period of 20years.By interfering superposition analytic method to predict water in 20 years evaluation period,the maximum drawdown of groundwater level at the borehole wall19.62m,the largest drop in well is 23.32 m,do not exceed the allowed drawdown of25.05m,which shows that the design exploitation is guaranteed.Water mining well group of 20 years,the total dissolved solids of groundwater is predicted to be0.515mg/L after mixing at the end of the forecast,which suggests that water quality is guaranteed after continuous exploitation of 20 years.The results of this study provides technical support for local urban planning and water supply,which also puts forward suggestions on the reasonable development and utilization of groundwater in the water source,provides a basis for the sustainable use of groundwater.