In the past 40 years China’s extraordinary economic boom has gone hand-in-hand with urbanization. But water management cannot keep pace with the rapid urbanization. In 2013 more than 230 cities were affected by flooding. With cities getting bigger and climate change threatening to bring more extreme weather, China has embarked on the ‘sponge city’ initiative since 2015. According to Chinese government 20% of developed urban area need to meet the sponge city construction goals of controlling 60 – 85% urban runoff and reduce 60% of nonpoint source pollutants measured by Total Suspend Solids (TSS) in year 2020 and the 80% by year 2030.
Sponge city concept is not just green infrastructure such as Low Impact Development (LID)in the United States, Sustainable Drainage Systems (SuDS) in United Kingdom and Australia’s Water Sensitive Urban Design (WSUD). It is a concept to redrawing urban landscape and to re-write the entire urban water cycle including but not limited to precipitation, surface runoff, infiltration, groundwater, drinking water, wastewater, combined sewer overflow (CSO), stormwater, rivers and lakes. From 2015 – 2016, 30 cities were chosen by central authority as pilot sponge cities. These cities will set up systems to manage runoff using source reduction (LID), inline storage or treatment and end pipe treatment (wetland, regional facility). Some cities will also use rivers and lakes as storage for extreme rainfall event by optimizing hydraulic structures and operations. However, the methods and mechanisms of doing this are varied and depend on the local situation.
With much involvement in pilot sponge cities from the master plans to engineering designs to construction observations the lecture will give many case studies that the sponge city could solve flooding and water quality problems. This means that we can redraw our urban landscape and water infrastructures.
In this lecture the speaker will share some experiences and lessons learned from several pilot sponge cities with the participants. The sponge city projects we have been in charged are underpinned by our cloudburst design principles, which are designed to mitigate flooding, reduce combined sewer overflows and remove pollutants from stormwater runoff using green, blue and grey infrastructure as a system approach. A detailed flood control project from design to construction using LID to retrofit an old high density residential neighborhood will be given step by step.