Medway River historical morphology (1812-present)

Chatham Eco-Urban Regeneration Plan

Chatham, UK

The City of Chatham commissioned a BAM+MSI study for urban and ecological regeneration. Located on the Medway River near the mouth of the Thames River, Chatham once enjoyed an exciting and thriving community life associated with the Rivery economy. Shipbuilding, naval dockyards, and lively piers formed a strong identity for the community. Although the River was highly used in the past, the City faces the current dilemma that it has now turned its backed to the river with its urban edge entirely facing inland. With no particularly exciting features remaining, Chatham needs a focal point to attract new residents and reverse the problem of a declining population.

Although the City was openly considering a new park to be built on the river’s edge as a solution to this urban problem, MSI+BAM research found that this solution would only be addressing one of the symptoms of a much larger problem. Chatham’s source problems are actually fragmentation of its ecosystem and its failure to activate there waterfront through a constructed civic edge. The problem requires thinking at a scale larger than Urbanism; it requires thinking at the Regional scale.

By analyzing the site at a larger, Regional scale, the nature of the river’s hydrology and Chatham’s relationship to it becomes more clear. At the regional scale the mouth of the river consists of zones of mud banks, flats, and oozes that create rich wetlands and important ecological zones. As the river moves further inland, the banks grow firmer, however, sediment and silt carried by the river is deposited throughout, creating smaller mudflats.

A historical analysis of the river morphology shows that in its earliest recorded state, the river charted a more undisciplined course, with finger-like tendrils spreading inland and larger areas that resemble the unspoiled mudflats nearer the mouth of the Thames. With the Industrial Revolution, the river bank became more constructed, minimizing the spread of the inland rivulets. Post-WWII urbanization continued the constructed nature of the river’s edge to its present day state. Currently, the mudflats occurring immediately adjacent to Chatham are littered with shopping cards, discarded washing machines, and used tires. Although the edge of the river is still constructed, its tidal nature and large sediment deposits prevent it from acting as an urban waterway.

BAM+MSI’s Chatham Ecopark creates a solution that is both better for nature and better for people. This Regional-scale design remediates the current fragmentation of the mudflat habitats by creating a larger eco-zone and lines the current downtown with a thriving urban water-edge. By emphasizing the distinction between the eco and urban zones, Chatham’s downtown urban identity can begin to flourish.

The design consists of two large infrastructural moves, the redirection of the river and the construction of an Eco Park. The river is redirected by re-cutting the historical flood path of the river and bypassing the oxbow portion that passes Chatham. Bypassing the oxbow allows Chatham to construct a storm surge barrier which protects their section of the River, which flows along their urban edge, to prevent changes in river level.

This bold move allows for Chatham to develop enormous areas of previously undevelopable riverfront real estate as a constructed urban edge. The river in this area becomes a series of perched tidal basins that are filled and replenished by tidal changes in the river. This effectively creates a fixed water level and allows for adjacent urban programs to enjoy the new waterway as cafes, piers, and walkways, and pedestrian bridges. The former waste sites along the river edge will become premium realestate with the installation of the tide basin infrastructure and the stom surge barrier.
The new Ecopark zone is actually the extension and demarcation of an existing wetland habitat. Wetlands in this environment are quickly regenerative, and therefore excellent material for the construction of ecological zones. This park zone is modified for flood water to spread deep into the parkland, thereby offsetting any of the floodplain lost as the river bypasses the new urban oxbow. The Eco park features a boardwalk eco-trail that passes through the islands of the park inviting visitors on an educational and healthy walk among the natural wetland habitat.

The downtown area of Chatham also enjoys a promenade boardwalk which links the urban edge with the ecopark to the North and creates a 1.6 mile historical loop connecting Chatham’s major historical sites. This urban promenade is bisected by an allee of trees marching down from the existing Urban Park and connecting the new river edge with the existing historical park.

Rethinking Chatham’s condition at a Regional scale reveals fundamental issues which can be resolved to conceptually rebalance both its urban and ecological environments. Rather than simply address Urbanism, this Regional thinking ultimately create a better setting both for nature and for man. Although a very bold idea, the hydrological redesign of the river also conceptually balances itself. The fragmented ecological wetland areas are redistributed in a larger ecozone, and flood plain area as the river is redirected is redistributed within the quickly regenerating wetland zones.

This conceptual Regional scale plan is currently under study by the City of Chatham. (This project completed by BAM in the office of Martha Schwartz, Inc.)

Project Facts Client: City of Chatham Hydrological Engineer: Moffet and Nichols

查塔姆市生态规划

英国 查塔姆市

为振兴城市和恢复生态,查塔姆市委托BAM研究出一个解决方案。依托泰晤士河(the Thames River)附近的梅德韦河(the Medway River)优势,查塔姆市曾充分发展沿河经济,城市因而也一度兴旺、繁荣。查市的民用造船厂、海军造船厂以及繁忙的码头曾使其声名远震。尽管河流在过去高度利用,但现在却要背离河流,而且城市边缘已完全面对内陆,现在查市正面临两难困境。考虑到城市已没有什么吸引人的亮点,查市现在就急需一个焦点来吸引新居民,解决城市人口下降问题。

尽管查市公开表示,要在滨区修建一个新的公园,以此来解决城市问题,但BAM经调查发现,这一办法只能引来更大的问题。河流的源头问题制约了生态系统的循环,也使得通过建设城市边缘来活跃滨区经济的计划搁浅。要想解决此问题,光从城市化的角度考虑是不够的,更要从整个地区的角度来考虑才行。

从更大的地区角度来分析查市,河流的水文特点和查市的关系也就越来越清晰了。从地区角度看,河口地区由泥滩、浅滩、和淤泥区构成,而这些又共同构成了各种各样的沼泽区和重要的生态区。然而,随着河流继续向内陆流去,河岸也越来越牢固,河水带来的泥沙和其他沉积物在这里完全沉淀,形成了许多小块的滨河泥地。

我们从历史角度分析河流的地貌,结果显示:在有记录的历史初期,河流流向更加随意,大致呈指状向内陆蜿蜒伸展,很多地方和现在泰晤士河口附近的滨河处女泥地十分相似。随着工业革命的进行,沿河岸建筑越来越密集,导致内陆河流的拓展范围越来越小。从二战一直到现在,沿河建筑随着城市化进程的日益加快而加快,一直到城市现在这个样子。现在,泥滩一接近查市,就被废弃的超市手推车、洗衣机和旧轮胎所充斥。尽管河流沿岸仍在建设,但河流的潮汐特性和大量沉积物沿河沉淀,使得查市难以成为航道城市。

本公司设计了查塔姆生态公园方案,本方案可以使人与自然和谐相处。本区域尺度设计通过创建一个生态区和将现有的商业区与繁荣的城市滨河区调整为一个整体,旨在恢复已经支离破碎的湿地生态系统。通过强化生态区和城区的区别,作为繁华的商业大都市,查塔姆将再次彰显她的生机与活力。

本设计有两大结构变动,一个是河流的再定向,另一个是生态公园的建设。通过对历史上的洪流通道再切割和对通过查市的河道进行截弯取直,河流再一次定向。取直河道后,查市可以修建一个防波堤。本堤可以保护河岸,驯服河水,保证河流水位长期稳定。

这次变动十分有魄力,此后,查市就可以大力开发滨河地带了。以前,这一地区的房地产业无法开发,现在正是其彰显活力的时候。河水经过此地,形成了一系列滞水潮盆,潮汐变化,潮盆得到补充,有效保证了河流水位的平稳。而平稳的水位也为一系列沿河项目创造了条件,如在新航道的旁边建零售店,修码头,建人行道和人行桥等。通过潮盆基础设施建设和防波堤的建设,曾经的荒芜之地将变成一流的地产区。

新生态公园区是现有生态湿地的分界和延伸。在这样的环境中,湿地可以在短时间内得到恢复,因其完备的生态条件,它将成为整个生态区建设的基础。河水过境城市的U形弯曲部分时,常使洪泛区损失严重。新区通过改造,将洪水引到公园腹地,这样就抵消了洪泛区的损失。生态公园内有一条生态木栈道,它贯穿园内所有的小岛,欢迎着游客到野外生态湿地进行教育之行和健康之行。

查市的商业区内也有一条木栈道,它连接着城市边缘和生态公园的北部,贯穿着查市的主要历史名胜,形成了一个长一点六英里的环形区,这创造了历史。林荫树木将木栈道一分为二,从现存的城市公园一直延伸,并将新河边缘和现有的历史公园连到了一起 。

从地区角度重新思考查市的情况,根本问题就有了眉目。而且从概念上讲,通过平衡城市与生态环境间的关系,这些问题是可以解决的。只想着城市化是不够的,要从地区角度着眼,真正创建一个人与自然和谐相处的环境。尽管这一想法很大胆,但从概念上讲,通过对河流水文重新设计,这一想法已经处于制衡状态。已经支离破碎的生态湿地在更广大的生态区内重新分布。随着河流的重新定向,洪泛区在迅速恢复的生态湿地内也得到了重新分布。

查市目前正在对此方案进行研究。(该项目由BAM在玛莎.施瓦兹公司完成)

项目有关方面: 客户:英国查塔姆市(Town of Chatham) 水文工程师:莫菲特和尼科尔斯公司(Moffet and Nichols)■

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