EFFECTS OF RECLAIMED WATER INFILTRATION ON AQUIFERS IN CHAOBAI RIVER AREA, BEIJING,CHINA

Most of rivers in Beijing, China are dry because of water shortages, including the channel of Chaobai River between Xiangyang dam and Henancun dam. From November, 2007 to October, 2016, it has been transferred about 20.5 millions m³ reclaimed water treated by microbial membrane reactor to that channel as ecological environment water. In order to find the effect of reclaimed water infiltration on aquifers beneath the channel, different depth monitoring wells (30m, 50m, 80m-depth) are drilled. Groundwater samples were collected and groundwater levels were measured regularly. It deduced that infiltration amount of reclaimed water was 14.5millions m³, which was 72 percent of total transferred reclaimed water. This indicated 44thousands m³ reclaimed water per day was infiltrated to aquifers. Groundwater level data showed that the hydrodynamic field of 30-m depth aquifer was obviously affected by reclaimed water infiltration, which was 25.2km². However, both 50 and 80-m depth aquifers were relatively slightly affected. The groundwater quality data revealed both 30 and 50-m depth aquifers were substantially influenced, the range of which was 19.9km² and 11.0km², respectively. Furthermore, the measured data also showed hydrological condition was closely related to environment change of those aquifers.