Case of fracture karst aquifer recharge with urban roofwater at home and abroad—Reflection on the relevant issues in Jinan City

Through monitoring and analyzing the water quality and quantity of the precipitation and rainwater fallen on the roof in Jinan City, it is found that the rainwater fallen on the roof being slight contaminated water; and that after removal the initial rainwater and pre-treatment the water on the roof can reach certain standard to recharge fracture aquifer, which can be used for drinking water and protection of groundwater environments. The former trace tests prove that most karst aquifer medium in north China is multiple fracture-channels, thus, the variation of water quality brought by fast and slow flow in recharge process, including the rock-water reaction between the karst fracture medium and the rainwater on the roof, should be paid attention in tificial recharge under the condition of artificial recharge. The case study in Australia illustrates that the karst fracture aquifer has different decay effects to different contaminants. Over 100 years, Mount Gambier reuses urban storm-water by discharging the water into an unconfined limestone aquifer that recharges the Blue Lake - the city’s domestic water supply. But there is no any measurable detriment to the water quality in the Blue Lake to date. Of course, there are still many problems need to be studied in recharging karst fracture aquifer with rainwater fallen on the roof in Jinan.