Abstract

Precipitation, evaporation and runoff patterns are changing, resulting in uncertainty about the security of water supply, the quality of drinking water, flood management in urban environments and the long-term health of natural ecosystems. The particular aspects for China are described where, with increasing urbanization, flooding has become a regular occurrence in response, China is developing “sponge cities” to attain resilience to stormwater. This paper describes a novel technology with significant potential; the principle of the ‘double pipe technology’ which involves placement of a perforated pipe below a stormwater pipe, encourages passage from the stormwater pipe down to a second pipe, a perforated pipe. This allows temporary storage in the lower pipe and enhances exfiltration from the lower pipe to the underlying aquifer. A conceptual model of the double pipe technology is provided, and the results show that the surcharge potential in the stormwater pipe is dramatically decreased. The lower pipe is able to capture, store, and eventually infiltrate into the groundwater, storm water runoff where the exfiltrate water from the lower pipe 56% to 62% of the total annual rainfall to be released to groundwater. This would truly enhance groundwater levels and decrease subsidence in areas where this is a major concern (particularly related to coastal zone cities in China).