E McBean 1 , Ai Li Yang 2 , Huiyan Cheng 2 , Yi Cheng Wu 2 , Zheng Liu 2 , Zhi Neng Dai 2 , Haiyan Fu 2 and Munir Bhatti 1 * 1 School of Engineering, University of Guelph, Canada 2 School of Environmental Science and Engineering, Xiamen University of Technology, Xiamen, China 3 Department of Dryland Science, Graduate school of Sustainability Science, Tottori University, Japan *Corresponding author: Munir A Bhatti, School of Engineering, University of Guelph, N1G 2W1 Guelph, Ontario, Canada, Tel: (1)519-591-0720; Email: Submission: May 26, 2018; Published: August 16, 2018 Evaluation of a Double Pipe Technology- Performance for Sponge City Research Article 1/2 Copyright © All rights are reserved by Kotaro Tagawa. Volume - 1 Issue - 5 Introduction China is a country with severe water problems including dimen- sions of water scarcity, flooding, and water pollution, all of which have been intensifying in urban areas and threatening socio-eco- nomic development. In recent years, urban flooding has become very frequent, pervasive, and severe. For example, it was reported that 641 out of 654 Chinese cities have incurred frequent floods in a survey conducted by the Ministry of Housing and Urban Rural Development (MOHURD). This study showed that over the period 2008–2010, 62% of 351 cities surveyed suffered urban flooding, and 39% experienced flooding on three or more occasions. Since 2008, the number of Chinese cities affected by floods has more than doubled, and at least 130 cities have experienced flooding nearly every year [1]. Making matters worse are also important issues of subsidence, with consequences that will exacerbate urban flooding problems. Land subsidence caused by extensive groundwater pumping has become a factor which cannot be ignored in the sustainable ex- ploitation of groundwater resources. The Hangzhou-Jiaxing-Hu- zhou Plain is one of the locations with China’s most severe land subsidence problems; the region has experienced dramatic land subsidence since the 1960s. Historical records of groundwater ex- traction, hydraulic head, and land subsidence show the latter to be the result of continual and excessive extraction of groundwater from deep confined aquifers [2]. For Beijing, almost two-thirds of the urban water supply comes from groundwater [3]. In recent years, water consumption has sharply increased due to the rapid expansion of Beijing’s population [4]. Groundwater extraction was measured as 2.6 x 109m 3 /yr., with an overexploitation of approximately 1x106m 3 /year [5]. This long- term overexploitation of groundwater has caused a substantial de- cline in groundwater and land subsidence. By the end of 2010, the land subsidence area reached 4.2 x 103km 2 and 66% of the Beijing plain has been affected by land subsidence (>50mm), with a maxi- mum sinking of 1.23m. As a consequence, attention is being given to alleviate issues of both flooding and subsidence. In this context, the double pipe technology described herein has particular merit since it can assist with attenuating flooding while also decreasing land subsidence by infiltrating surface water to groundwater. This paper describes research results investigating the potential performance of application of the double pipe technology in Beijing. 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). Advancements in Civil Engineering & Technology C CRIMSON PUBLISHERS Wings to the Research ISSN 2639-0574