Numerical simulation of groundwater pollution in hilly areas with complex terrain based on GMS

Groundwater resources are an important source of drinking water and are of strategic importance. Leakage of storage materials or wastewater may occur during petrochemical production, leading to groundwater pollution. Taking a petrochemical construction project in complex hilly region of Hunan Province, China as an example, a groundwater flow and solute transport model was established by using groundwater simulation system GMS according to engineering analysis and investigation. According to the characteristics of hilly and plain areas, the precipitation infiltration recharge was calculated by using the hydrology method and precipitation infiltration coefficient method respectively to improve the simulation accuracy of the model. The model was established to simulate the solute transport of toluene, COD, ammonia nitrogen and petroleum on the 100th, 1000th day and 20th yearafter leakage of a tank farm and sewage treatment plant under abnormal working conditions. The results show that organic pollutants are mainly controlled by convection, and inorganic pollutants are controlled by convection and dispersion, and the pollution halos would all move out of the construction area after 20 years, but not out of the simulation area. In order to prevent and respond to and deal with pollution incidents in a timely manner and minimize the impact, zoning and categorization of seepage control measures should be taken, and a groundwater monitoring plan and an emergency plan for pollution treatment should be formulated.