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Sponge City Construction in Ningbo
2019-08-09Text Size: A A A

Marked progress has been made since 2016 when Ningbo was listed as one of the pilot cities for the construction of sponge cities. As of the end of June, 126 pilot projects, 84% of the total, have been concluded. According to the progress plan, all construction in pilot areas will be completed by Oct this year. The construction of sponge city has brought about welcome changes. For instance, Puddles or waterlogging after rain have been addressed and tropical island effect is notably alleviated. Much more follows.

Ningbo & Sponge City

The relations between a city and its waters can be managed in mainly 4 ways, namely absorption, storage, permeation and purification. One instance can make plain the role of a sponge city in improving urban water management. In a sponge city, roads are permeable, allowing rain water to be absorbed and stored as part of the underground water, which can be efficiently recycled for future use. These new capabilities can better urban water management, turning a city into a huge sponge.

Looking around, Germany and Switzerland are paradigms we should look to in terms of water management. However, Ningbo is also doing its part to build itself into a sponge city.

Ningbo’s unique geographical position and climate gain itself the upper hand in the construction of a sponge city. Situated in the subtropical monsoon climate area, Ningbo had long been plagued by floods, damp, typhoons and tropical storms owing to its natural geography, which put Ningbo at the risk of waterlog. This was compounded by the unreasonable water management in the past which caused damage to Ningbo’s aquatic ecosystem.

Given this situation, Ningbo was listed as one of the 17 pilot cities for the construction of sponge city in 2016, which comes as a powerful solution to Ningbo’s problems in urban water management.

The results have been evident. First, the construction of sponge city is a formula aiming to revolutionize traditional water management, which solely relied on the drainage of rain water pipes. Instead, it now focuses on the storage of rain water.

Second, a sponge city can greatly facilitate household water consumption. A sponge city can “absorb” excessive rain water and “squeeze” it in times of water shortage, effectively boosting the recycling and reuse of rain water. In addition, water-saving equipment can also enhance the recycling of rain water, thereby reducing tap water consumption. It is estimated that almost a hundred million cubic meters of water can be saved annually in urban area in Ningbo.

What’s more, the construction of sponge city represents the preservation and protection of existing waters. The aquatic ecosystems of water, riverbeds and riverbanks will all be improved in accordance to their natural conditions. With wetlands, rainwater gardens and vegetation, rain water can be purified as it runs through these facilities before it is discharged into the inland river. With these two approaches, the aquatic environment in Ningbo can see an overall improvement.


Progress Made in Building a “Sponge City”

With abundant precipitation yet shortage of resource-type water, Ningbo is pressing for a solution, that is, to build the city into a “large sponge” that can absorb, store and discharge water. Starting from scratch, the city is marching towards its goal and breaking new ground in water management.

Ningbo has made some trials earlier in 2016. Efforts include building sponge roads in Cichen New Area, Jiangbei District, constructing sunken green belt and drainage lake in central areas, and purifying and recycling polluted rainwater runoff. In addition, a special water purifier has been built in line with the geological, hydrological and vegetative features in the city’s Eastern New Town, which underpins local ecological sustainability.

The 30.95 square-kilometer (11.25 square-mile) pilot area of “sponge city” lies in Cichen-Yaojiang district. A total of 171 projects in 6 categories have been launched in the area, including sponge-type communities, roads, parks, green space, water systems, and ecological recovery, flood control, water management capability building.

On April 22rd, 2016, Ningbo was listed as a pilot area for building “sponge city”, financially supported by the central government. The success should be attributed to its extraordinary plans of projects and implementation. According to the plan, the city will combine surface and underground water management, and integrate storage, purification, recycling and discharge, to improve water ecological environment, enrich water resources, safeguard water security and create distinctive culture of water. It is projected that over 25% of the city’s built-up areas will meet the standards of “sponge city” by 2020 and over 80% by 2030.

To win the approval of the central government, Ningbo has braced itself well. The city has formulated and approved special projects whose goals and requirements are put into practice in zone planning and detailed items of controllability. Also, a series of systems have been improved in water resource protection, water supply and drainage management and unconventional water use.

Thanks to the efforts, a sponge city covering 2.84 square kilometers (1.09 square miles) has towered in the area hardest hit by inundation, maintaining the annual runoff control rate above 75%. Moreover, the number of severely polluted rivers teeming with stink and junks has reduced gradually. Residents are delighted to find that the overall water quality in the city is on the rise.

The sponge city project has been advancing for three years

After the successful selection, the Cicheng-Yaojiang area has undoubtedly become the focus of the entire project, with the gradual improvement of the project.

In November 2016, “Ningbo Implementation Opinions on Promoting Sponge City Construction” was launched. By 2018, the Cicheng-Yaojiang pilot area in Jiangbei District, covering an area of 30.95 square kilometers, met the national pilot city construction assessment requirements. By 2020, more than 75% of the rainfall in the central city will be treated locally, and more than 25% of the urban area will meet the target requirements, and by 2030, it will reach more than 80%.

This huge project includes five key tasks, including comprehensive improvement of urban water environment, residential buildings and community storage, urban parks construction, drainage of urban roads and plazas, and construction of urban and rural integration. All of this is closely related to the various elements of life around the residents.

Over the past three years, the progress of the project has been very gratifying. By the end of June 2019, there were 126 completed projects in the pilot area, with a completion rate of 84%; the completed drainage area was 23 square kilometers, accounting for 74% of the pilot area. It is expected that the construction of the pilot area will be fully completed in October 2019. In addition to Sanhe Jiayuan Community and Yaojiang Garden Community, the residential area renovation project also includes old buildings such as Guangsha Yiting, Chunhui Jiayuan and Ningxin Garden.

Among the renovation projects, the task of transforming the old community can be described as a major difficulty. As of the end of June, Jiangbei District has been organically integrated with the renovation of the old community through the construction of “The Sponge City”, with 95 projects under construction and 43 completed. Among them, the Xiejia District of Tianshui, where the Guangting Community is located, has 19 old residential quarters undergoing “sponge+” transformation.

Road and garden improvement are carried out simultaneously. Traditional roads have problems such as water accumulation in rainy days, rainwater well drainage of part of roadway and sidewalk, damage of ground bricks, etc., which results in huge pressure of municipal pipe network, low utilization rate of rainwater, and high pollution. Some gardens are high in the middle and low in the sides, which leads to the problem of water flowing onto the road once it rains heavily.

Breach has been designed under the side stones of the road to connect the edge to the ecological tree pool, allowing for the purification of rain water without overflow. In addition, the addition of ecological means to the road not only replenished the groundwater, but also eased the pressure on the municipal pipe network. The rain garden also brings new ideas to the relationship between the garden and the water. A rain garden of about 200 square meters was designed and built at Ningbo Technician College.In the garden, there are not only abundant vegetation varieties, but also the water in the garden seeps into the ground through the hollow ground in the middle of the greenbelt, which is filtered and purified and discharged, realizing the integration of aesthetics and pragmatism.

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