Comparative Analysis on Urban Flood Countermeasures Based on Life Cycle Thinking: A Comparison between Enhancing of Drainage Capacity Project and Sponge City

Abstract

<jats:p>The recent increase in rainstorm waterlogging disasters has acutely threatened sustainable urban development in China. Traditional strategy to solve this problem is drainage capacity enhancing projects, which aims at enlarging the discharge of water. Recently, there is a new countermeasure emerged in Chinese cities: ‘Sponge City’, which aims at enlarging the absorption of water by increasing the curves of urban land. This article endeavours to make a comparison between these two countermeasures by building a framework to design and analyze the private or social costs of two projects which have the same rainwater control capacity. Finally, we have come to the conclusion that only considering initial cost, Sponge City unit cost is much more than drainage capacity enhancing project unit cost; considering external cost, Sponge City is not only competitive from an economical perspective, from an environmental perspective Sponge City is also competitive.</jats:p>

Meeting financial challenge facing China's Sponge City Program (SCP) – Hong Kong as a gateway to green finance

“…Thirdly, in comparison with traditional engineering drainage capacity enhancing projects, the up-front cost of sponge city facilities achieving the same rainwater control capacity is much higher [75], but the paybacks usually last over a long-time span. Many private investors might not be able to adequately aware of the long-term financial benefits, like accounting and reporting in financial markets tend to reward short-term over long-term investment.…”

A Systematic Review Comparing Urban Flood Management Practices in India to China’s Sponge City Program

“…Nangang district in Harbin city of Heilongjiang province consists of drainage systems dating back to 1904 with a conduit capacity of 18 mm/h and drainage capacity of 135 m 3 /h, which fall short of the drainage capacity stipulated by the standards (185 m 3 /s) to tackle moderate rainfalls of 25 mm/h. 'The Harbin water supply and drainage industry development strategic planning proposes to undertake sponge city facilities and drainage upgradation between 2020 to 2025 to overcome the current waterlogging challenges the city undergoes even during moderate rainfall events [27].…”

“…The restoration and reconstruction of underground structures such as pre-existing drainage structures from older parts of cities need to be tended to as well to achieve real results. Fan and Matsumoto [27] view the SCP as a measure to increase the "curves" in urban areas to increase water absorption.…”

“…The debate on the higher initial cost requirements for sponge city facilities when compared to traditional drainage enhancement procedures is addressed by Fan and Matsumoto [27]. They found that, in the case of a district in China's Harbin city, though sponge city implementation is more expensive in the initial phase [2], the project is expected to achieve carbon neutrality after 3 years and can double up as a carbon emission reduction factor, saving up to 198 tons of carbon dioxide emission per year in addition to absorbing 1.9 tons of NOx emissions, making it hugely advantageous from both financial and environmental perspectives.…”

Combining SAR images with land cover products for rapid urban flood mapping

“…Urban flooding is a major natural hazard triggered by shortterm heavy rainstorms or continuous precipitation exceeding the drainage capacity (Shahapure et al, 2010;Zhang et al, 2020). In part due to a globally changing climate and excessive urbanisation, urban flooding has become increasingly frequent and resulted in severe devastation to economies (Huang et al, 2018;Fan & Matsumoto, 2020;Pervin et al, 2020;Tayyab et al, 2021). In South Korea, the economic losses in Busan metropolitan city due to urban flooding amounted to US$1.5 billion from 2007 to 2016 (Dao et al, 2020).…”