Research Progress of Groundwater Supplemented by Urban Rainwater

Increasing surface rainwater infiltration to recharge groundwater by improving the condition of the underlying surface is an important goal of resilient city construction, as well as a vital initiative for utilizing rainwater resources and alleviating urban water shortage. This study examined the utilization of groundwater supplemented by urban rainwater in China and abroad and reviewed the challenges and shortcomings faced by the utilization of groundwater supplemented by urban rainwater at the present stage from the aspects of recharge methods, water quality problems, numerical simulation, and relevant policies and regulations. The study proposed future research directions in this area, including solving clogging problems in artificial recharge techniques and accurately calculating the actual groundwater recharge from artificial retention infiltration measures. As groundwater is supplemented by urban rainwater runoff, it is necessary to strengthen peak shaving and pollution reduction at the source, process control, and end-of-pipe treatment. In the future, the numerical simulation in the field of groundwater recharge should focus on the numerical simulation coupling of hydrological models and groundwater models, vigorously develop regional and site coupling models, and finely delineate the process of groundwater supplemented by rainwater runoff. China's rainwater utilization policies and regulation system have room for improvement, so it is recommended to promote rainwater utilization legislation, so as to provide direction and reference for further research and management related to rainwater gathering and utilization, as well as groundwater supplemented by urban rainwater.