The ‘sponge city’ concept can prove useful to Kerala cities such as Kochi for tackling floods, but it should be borne in mind that this is also a gradual process where benefits are reaped over a period of time, Sun Xiang, senior engineer/ project manager, Shenzhen Water Planning and Design Institute, China, has said.
Mr. Sun presented the concept at a conference on ‘Policies and strategies for flood management’ organised by the Water Resources Department here on Thursday. On Wednesday, he toured Kochi accompanied by department officials.
Southern Chinese city Shenzhen was among the first of 30 cities in China to adopt the sponge city initiative, an integrated solution which equips urban locales to effectively tackle floods and utilise rainwater efficiently. The Irrigation Department is probing whether the Chinese initiative can be adapted for Kochi, which was ravaged by the 2019 floods. “I’m not saying it can be done in two or three years. It is a gradual process, where the city becomes better and better. It is a step-by-step process just like the development in Shenzhen,” Mr. Sun said.
Shift in mindset
Strict regulations, widening the rivers, dredging canals criss-crossing the city, and better management and maintenance can help Kochi handle floods better, he said. “Shenzhen has done all of this over 10-15 years,” Mr. Sun said. An important aspect of the Shenzhen experience was the mindset shift from “fast drainage to sustainable storm water management.”
An integrated solution, the sponge city concept combines flood control, legislation, water resources management, rainwater harvesting, water purification, and governance. China launched the sponge city initiative in 2015. In 2016, 14 more cities were added to the original list of 16 cities.
Sponge city challenges for Shenzhen, which covers approximately 2,000 sq km, included tackling storm surges, typhoons, lack of water resources, and flood drainage mechanism, Mr. Sun said. Challenges were addressed in multiple stages; between 1980 and 2005 as ‘separated flood control’, in 2006 as a three-in-one concept of flood control, pollution control and landscaping; and the ‘blue line planning’ stage in 2007 where the government passed a law.
In 2013, the government published a new edition for flood control planning, which served as a master plan. The sponge city initiative was rolled out two years later.
