时间 2014年9月13日; 地点 黄山市西溪南镇; 拍摄 俞孔坚
The Lv Weir, one of the weirs along the Fengle River in the town of Xixinan, was built in 527 A.D.. Low weirs, such as Lv Weir, are very common in the region of Huizhou. Only elevating the water for a few feet, the weirs help slow down the mountainous torrent and irrigate vast farmlands without disturbing the regional structure of the natural water system. The weirs are connected with distributed ponds in the village and the field, reflecting beautiful scenes described in some poems, and creating an integrated water management system that is exactly the same as what a Sponge City would act. Unfortunately, the stone weirs have been gradually replaced by concrete andsteel structures which perform as the low weirs but without the ecological and aesthetic values.
I have done a lot of work — often forwarding thinking and groundbreaking — for the design and construction of Sponge Cities, but the true driving force in the development of a Sponge City is proactive administration by President Xi Jinping and related national departments. In the spirit of urbanization put forth by the central government, the notion of a Sponge City was clearly mentioned in February 2014. In Working Points of Ministry of Housing and Urban – Rural Development of the PR China in 2014, the central government urged local governments to increase reform of rainwater and sewage diversion, improve urban flood systems, and carry out low-impact development. The Ministry also urged policy research into Sponge City construction, and published Sponge City Construction Techonlogy Guidelines in October 2014. Sponge City programs were carried out from the end of 2014 to the beginning of 2015, selecting 16 cities as the first pilot cities. The Sponge City concept was clearly proposed in planning documents, but it became public almost overnight. Its incorporation into official rhetoric represents how the ideology and technology of ecological stormwater management has been raised to policy level and become a powerful part of professional practice. However, currently, most guidelines are still about learning best practices of LID, Water Sensitive Urban Planning and Design from western countries, specially focusing on the internal urban drainage system and the utilization and management of stormwater. The interpretation of specific technology still depends on engineering strategies.
The concept of Sponge City is more than that. It will start a new journey for approaching water issues and other prominent environmental issues at different scales, including stormwater management, ecoflood control, water purification, supplements of underground water, restoration of brownfields and urban habitats, and improvement of green spaces and urban micro-climates. We need to better understand the concept of the Sponge City; otherwise it will fall through the cracks and be treated as an “excuse” for power rent-seeking of some central government agencies, a “stimulus” for local economic growth, and an “opportunity” to engineering companies to profiteer; or even start a new round of “destructive projects” such as artificial channels, lakes and hills. The philosophy of Sponge City should inspire a rebellion against traditional engineering practices. We need to consider the following:
Value complete ecosystems rather than provincial interests. The public attitude towards rainwater is utilitarian and selfish. Workers at a tile factory might pray for a sunny day, while farmers suffering from drought pray for rain. The Sponge philosophy is inclusive of multiple approaches to rainwater. It values the affect that rainwater has on an entire ecosystem, not just one group of people or species. Humans benefit the most from a Sponge City, but we must remember that every drop of rain water has value and meaning. Sponge City cherishes and intends to conserve every drop of the gift from the nature.
Resolve water issues on site. Transferring risk, through shifting water from one place to another, is the intension and solution of almost all the modern hydraulic engineering projects, even often with disastrous consequences. For example, levees and long distance water transport drains water downstream, often taking it away from water-scarce regions or disadvantaged groups. The Sponge City draws on historic practices to regulate flood and drought conditions on-site and conserve runoff. The Sponge philosophy does not only grow on the ancestors’ wisdom and sacrifice in regulating flood and drought but also embodies geographical society and neighborhood. It is a sorrow to recall that some members of my family died in fighting for increasing the height of the weir in order to lead more water of the Baishaxi River for irrigation.
Decentralize civil projects. Traditional hydro projects, such as King Yu’s taming of the flood or the Three-Gorges Dam, reflect a nationalized power through civic infrastructure. Centralized systems have dominated in China for a thousand years. It is necessary in some cases, such as Dujiangyan irrigation system, the hydraulic project with the lasting positive effect on the western Sichuan Plain. But, overall, the failings of centralized projects — dams, levees, and urban drainage projects — are too great to count. Centralized projects that work against, rather than with, ecological forces are not in our best interest. Distributed civil hydraulic projects are more sustainable. Mass, micro-hydraulic projects spread over ancient farmlands, and are maintained by the local people. These types of systems are far more successful in the long run than single-used macro engineering projects. More and more of these types of landscapes are being destroyed in favor of larger, powerful national hydraulic projects. The Sponge City will distribute water to form a larger system of integrated units. We call for conservation of these projects which are nondestructive to natural watershed structure and integral to the establishment of a nationalscale Sponge system.
Slow down rather than speed up, store rather than discharge stormwater. The basic philosophy of modern anti-flood projects is to rapidly drain stormwater. Smooth channel interfaces are regarded as the most efficient and direct form. As a result, removal of trees and shrubs on riverbeds is taken for granted in order to reduce hydraulic “resistance”. Such “quick-focus” hydraulic projects neglect the systematic nature of water so that the destructivity of the flood is strengthened and transfers the upper river disaster downstream. Channeling separates water from creatures, from land, from textures and surfaces, people and cities. They deplete groundwater and make habits degenerate. The Sponge City will slow down and tame the water, and enable downward movement that will help infiltrate and supply groundwater, benefit wildlife habits, and purify water to better serve urban environments.
Flexible rather than rigid resistance. Modern anti-flood projects miss an important aspect of Chinesephilosophy — taming hardness with softness. Few rivers are free from the constraint of a rigid levee in China. The original meandering rivers have been turned into stiff and straight drainage channels. Floods from these types of rigid systems result in massive destruction that destroys everything in their path. The Sponge philosophy encourages flexibility, so the best to interact with water is to tame hardness with softness.
Sponge City philosophy highlights a conversion from big to small, from exclusive to inclusive, from centralized to distributed, from fast to slow, and from hardness to softness. At the heart of this position is what Lao-tsu said: Nature does not hurry, yet everything is accomplished. When Sponge City becomes a popular slogan, thorough understanding of its philosophy turns out significant.
原文出处：俞孔坚. (2015).海绵城市. 景观设计学, 3(2):4-9.
Source: Yu, K. (2015).Sponge City.Landscape Architecture Frontiers, 3(2):4-9.