Numerical Simulation Of Groundwater Flow In Spring Discharge Area And Protection Measures To Water Resources

Spring discharge is decreased significantly or even disappeared in the north China in recent years due to artificial influences, which endangers ecology and environments in the regions. Therefore, it is very important for water resources protection and management to analyze influences to spring discharge and simulate their variations. The study is one of the key prerequisites to meet the requirement of water resources and ecological and environmental protectionsThe study area is situated in the Xiao-nanhai spring catchement in Anyang city, Henan province. A numerical groundwater model is developed using MODFLOW and its calculation was based on geological and hydrogeological data in the study area. Groundwater flow system is assumed as Darcy flow in the continuum of the aquifer, among which the fast flow is approached by the seepage flow with the larger hydraulic conductivities. The hydrogeological parameters are calibrated by comparing observed and simulated groundwater tables and spring discharges. Influences of precipitation, surface water from rivers, channels and reservoirs and groundwater withdrawals to spring discharge variations are revealed through water balance analysis. The study results demonstrate that precipitation recharge amount and river flow infiltration amount are 50 and 44 percent of the total water recharge amount, respectively. Spring discharge is approximately 54 percent of the total water discharge amount and 44 percent of the total recharge amount. The secondary discharge is groundwater withdrawal for agricultural and industrial utilizations and withdrawal for lowing groundwater table in the mines. Their amount is 31 percent of the total groundwater discharge amount or 12 percent of the groundwater recharge amount. Moreover, groundwater withdrawal takes more significant influence to groundwater in the drought periods. For examples, groundwater withdrawal amount could even be approximately 44 percent of the total recharge amount in the drought season of 2002.The influences of climatic variations and artificial activities to spring discharges are further analyzed using the model. The measures to maintain spring discharges by increasing irrigated water and reducing agricultural and industrial groundwater utilization are suggested in the study.