Impact of an artificial lake on the regional groundwater environment in urban area of northwest China

Abstract

In many densely populated urban areas, artificial lakes have replaced natural river systems as water sources to provide people with water for living and industrial production. However, groundwater mounding due to seepage from water storage facilities will have an impact on the regional groundwater flow regime. This study investigated the effects of the construction and operation of the Doumen Reservoir in northwestern China on the local groundwater flow regime. Groundwater level variations before the construction of the impoundment were analyzed by wavelet analysis and indicated that most of the observed variations in levels were due to changes in groundwater abstraction in the area. Data were collected from drilling and real-time monitoring; a coupled Hydrus-1D and MODFLOW model was developed to simulate the impact of water storage on the surrounding groundwater environment. The simulation results show that compared with the initial flow field, the maximum elevation of the groundwater mound that would develop beneath water storage structured in the area would vary between about 4.9 and 6.9 m. Compared with the impoundment of the test section, other modeled scenarios will cause varying degrees of groundwater mounding around the reservoir area but no flooding of existing infrastructure is predicted to take place. The predicted seepage rate from the facility is 3660 m3/day, and anti-seepage measures are recommended to limit the effects of groundwater mounding.