COMPARISON OF ARTIFICIAL WATER DIVERSION AND SPONGE CITY FOR GROUNDWATER RECHARGE

With the rapid development of urbanization and the rapid increase of urban population, urban water demand has increased markedly, resulting in excessive exploitation of groundwater in many cities. At the same time, with the increase of urban construction area, the proportion of impervious area has increased year by year, blocking the paths of rainwater seepage, resulting in the reduction of groundwater recharge volume. Excessive exploitation of groundwater resources has caused a series of problems such as uneven ground settlement, groundwater pollution, and seawater intrusion. In view of the above problems, taking a city in China as an example, the comprehensive benefits of artificial water diversion and sponge city to promote recharge of groundwater were compared in terms of water quantity, water quality and engineering reliability. The results showed that the groundwater recharge of the artificial water diversion was about 7.79×10⁶ m³/a, and the groundwater recharge of the sponge city construction was 3.39×10⁶ m³/a. The pollutants of the two methods were similar, but there existed large great fluctuation of the concentration of rainwater runoff pollutants. Therefore, artificial water diversion had the advantages of easy control of water quantity and relatively stable water quality, but the water volume was limited by the available water sources. While ensuring the effect of groundwater recharge, sponge city construction also had multiple benefits such as rainwater runoff pollution control and flood mitigation. The comprehensive benefits were relatively high, and it's more in line with the concept of sustainable urban development.