Groundwater Modeling Of Artificial Recharge In Beiyun River Water Resources Recycling Project

The main stream of Chaobai and Beiyun River, which flows through Tongzhou and Shunyi district in eastern Beijing, plays an important role in the economic development of Beijing. Aiming at the fact of ecological environmental deterioration, the rate of groundwater decline should be mitigated and reasonable planning of water resources needs to be put forward. Specially, reutilization of treated wastewater is quite necessary in Beijing and will contribute a lot to the thirty city.We choose the upper and central reach of alluvial-pluvial fan as our study area with purposes as follows: 1) zone the groundwater resource protective area; 2) predict the change of flow field after groundwater artificial recharge; 3) quantitatively determine the ratio of recharge water in the exploited groundwater and the residence time of recharge water from injection well to water source areas.GMS was used to establish the groundwater model in the area. A calibration of one-year and validation of ten-year data were carried out to confirm that the model is appreciated to our study area. Then groundwater model was established: a recharge of 86.4×104 m3/d was durative for 5 years, then groundwater level rises about in an average of 14.68 m under scheme 1, while it rises in an average of 13.93m under scheme 2. Results show that scheme 1 can enhance a larger value and area of groundwater level rising, thus it is more useful to groundwater level recovery.Using groundwater forecast model from 2009 to 2014 as the dynamic field of solute transport simulation, we obtained the region of capture filed of solute transport in 100 and 1000 days with an area of 18.84 and 91.54km~2, which are the region of first and second order protection area, respectively.Using the groundwater forecast model from 2015 to 2019 as the dynamic field of solute transport simulation, we got that when the ratio of recharge water in the exploited groundwater reaches 80%, groundwater level tends to stationary, and the ratio under scheme 2 is larger than that under scheme 1.We also use groundwater forecast model from 2015 to 2019 to carry out the study of particle tracing. Results of positive tracing show that most of recharge water reaches to Shuiyuanbachang in 1~2 years. The negative tracing was used to calculate the capture zone area of exploited wells in Shuiyuanbachang: 8.85 km~2 under scheme 1 and 7.57km~2 under scheme 2. Capture zone under both schemes are very small, showing that recharge water will be the dominant source of groundwater in Shuiyuanbachang.