7

“Drains to Bay”

第七章

流入海湾的下水道

On the curb across the street from my office there is a sign with apicture of a little blue fish ringed by the words, “No Dumping—Drains to Bay.” Underneath the sign sits the storm sewer—an entry point for rainwater traveling through the underground pipe system designed to protect the sity of Berkeley, California, from flooding. Any water flowing into the storm sewer makes a speedy trip under the city to a pipe that ends at the edge of San Francisco Bay. Along with the rainwater, anything else that has found its way into thestreet, like trash, leaves, or dirt, gets dumped into the bay and beyond.

在我办公室的窗外有一条街道。街那边的路旁有一块指示牌，上面画着一条蓝色的小鱼，围着小鱼的是英文字母组成的一个圆圈：“禁止倾倒（垃圾）———（这是）流入海湾的（雨水）下水道！”在指示牌的下面是雨水下水道———这是一个雨水的入口，雨水由这里流入地下管道，保护加州伯克利城免于洪涝。流入这个下水道的任何水，都会通过城市地下管网快速汇入主排水管，该管的出口在旧金山湾的边缘。跟随雨水一起流入海湾和更远处的，还有街道上其他可以与水一起漂流的东西，如垃圾、树叶或尘土。

The storm sewers in your neighborhood, which may or may not have acute sign stenciled above them, might follow the same practice, draining rain and melted snow to a local stream, river, lake, or bay. Then again, they might be connected to the same underground pipe system that carries wastes from your home to the sewage treatment plant. Either way, these long-ignored systems are falling apart. And as they deteriorate, they will endanger our health as wellas the habitats of fish, insects, and birds living in and around our inland and coastal waters.

小区的雨水下水道，无论是否拥有可爱的标识，都具有相同的功能：将雨水、融化后的雪水排入当地的小溪、河流、湖泊或者海湾。此外，它们还有可能连通到同一个地下排污管系统，和你家的废弃物一起排入污水处理厂。无论哪种方式，这些长期被忽视的地下管道系统，目前正濒临崩溃。随着这些系统的老化，我们人类的健康和生活在内陆及沿海水域里的鱼、昆虫和鸟类的栖息地都将会受到威胁。

Like the underground pipe networks developed to remove wastes from homes and streets during the nineteenth century, the urban drainage systems built over the past three centuries were an expedient means of moving unwanted water out of cities. But in the process of solving one problem, we created a new one: although the sewers quickly transported large volumes of water away from flood-prone streets, they often damaged the places where the water was discharged. In light of the difficulties faced by cities currently struggling to repair decaying pipes and to keep up with the increasing volume of water their existing drainage systems, it evident that in the near future we aregoing to have to spend hundreds of billions of dollars on these concrete and cast-ion plumbing systems.¹

与１９世纪修建的用于移除家庭和街道废弃物的地下管网一样，过去３个世纪里建立的城市排水系统也仅仅是一个权宜之计，用以移除城市里不需要的水。但是在解决了一个问题的同时，我们又制造出新的问题：尽管这些下水道可以快速排掉街道上大量水，但它们又会对排水口的出口所在地造成破坏。鉴于城市当前面临着需要努力修补的破损管道，以及跟上日益增加的污水排出量等问题，在不久的将来，我们将不得不花费上千亿美元的资金去维护这些由水泥和铸铁制造的管道系统^［１］。

The need for huge investments in urban drainage also represents an opportunity: by building new types of drainage systems that take advantage ofthe ability of natural systems to store and purify water, we might be able toend up in a better place. With a little ingenuity, we can reinvent storm sewers in a manner that saves money, improves the environment, and even replenish our drinking water supply.

更新城市排水系统需要巨额投资。但是，这也意味着一个契机：通过利用天然系统存储和净化水体的能力，建设新型排水系统，或许可以使我们获益良多。通过独具匠心的设计，我们能够新建一种雨水下水道，能省钱、改善环境，甚至还能补充供水。

Why does a city need a drainage system, anyway? Consider what happens when rain lands in a park, a plot of forest, or a farmer’s field. Much of thewater percolates into the soil, where it provides moisture to plants andrecharge groundwater. The water that does not soak into the soil flows gently downhill under the force of gravity. Along the way, it forms rivulets, which join together to form a network of streams and rivers.

然而，为何一个城市需要排水系统呢？想象雨水落到一个公园、一片森林或者是一块农田的情景。大部分水会渗入土壤里，为植物提供水分，补充地下水。未渗入土壤的水会在重力的作用下慢慢往低处流。这些水在沿途积流成溪、进而汇聚，形成一个由溪流与河流组成的网络。

Now consider the consequences of covering the land with buildings and other impervious surfaces that prevent water from soaking into the soil. If the hard surfaces were perfectly flat, the accumulated water would form gigantic puddles. But this rarely happens because most land is sloped, even after it iscovered with asphalt or concrete. As a result, all the rainwater still flows downhill. If this large amount of water were to stay in a city, it would turn streets into rivers every time it rained and, much to the chagrin of homeownersand insurance agents, flood the basements of homes in low-lying areas. This process is exactly what happens in slums of developing countries that have been built without storm sewers.

现在，想象一下当土地被建筑物及其他不透水的表面所覆盖，从而阻止水分渗入土壤的结果 。倘若这个坚硬的地表足够平坦，积累的水将会形成一个巨大的水洼。当然这比较少见，因为即使土地铺上了沥青或混凝土后，大部分的地面还是倾斜的。于是，所有的雨水依然往低处流。如果大量的水积存在城市里的话，每次下雨时街道都会变成江河，地势较低的地下室会被淹没，给房主和保险机构带来很多烦恼。这种情况在发展中国家的贫民窟尤为常见，因为他们没有雨水下水道。

(Last two paragraphs of Chapter 7)

The public is usually oblivious to urban drainage problems. Consequently, if low-impact development is going to succeedat the scale of an entire city, committed advocates are needed from outside ofthe water sector. One of the best examples of the level of commitment needed to successfully launch a citywide low-impact development project is Philadelphia’s “Green City, Clean Waters” program. Faced with the prospect of an expensive retrofit to address its combined sewer overflow problem, Philadelphia’s mayor, Michael Nutter, decided shortly after his inauguration in 2008 to pursue low-impact development as an alternative to the conventional engineering approach.⁴⁶ But simply choosing low-impact development over underground tunnels was not enough. In addition to pushing for cooperation from the city’s water department, which had led previous efforts to combat the city’s combined sewer overflows, the mayor enlisted support from the government departments responsible for Philadelphia’s parks, schools, transportation, and taxcollection. After he got the buy-in from city agencies, he turned to sellinghis program to the public. To do this, he established a comprehensive program called “Greenworks Philadelphia” that explained his vision for the ways in which green infrastructure would transform every aspect of city life. Inessence, he made a commitment to supporting green development as mayor.

公众一般不会关心城市排水系统的问题。因此，低影响开发模式想要在整个城市范围内获得成功的话，还需要获得水务部门之外的官方承诺。在城市范围内成功落实低影响开发模式所需要的支持的一个最好的例子，是费城的“绿色的城市，干净的水域”项目。面临解决合流制排水系统溢流问题需要花费昂贵资金，费城市长米歇尔·纳特尔在其２００８年的就职演讲后不久，决定采用低影响开发模式来替代传统方法^［４６］。但是，一步到位地选择低影响开发模式来代替地下蓄水库这一决定本身是不够的。除了寻求一直在为解决合流制下水道溢流问题努力的水务部门的合作外，市长还寻求那些负责费城公园、学校、交通和税收等政府部门的支持。在这些部门都乐意支持他的时候，他开始向公众推销他的项目计划。他成立了一个名叫“费城绿色工程”的综合项目，用以阐明他的远景：采用绿色基础建设将会改变城市生活的每一方面。从本质上讲，作为市长，他对支持绿色事业的发展做出了一个承诺。

The consent decree that the mayor signed in 2012 with the Environmental Protection Agency commits the city to a twenty-five-year program that will cover about one third of the city’s impervious surfaces with green roofs, raingardens, permeable pavement, and other low-impact development features capable of capturing and retaining the first 2.9 cm (one inch) of precipitation.⁴⁷ If everything goes according to plan, Philadelphia will invest approximately $2.5 billion in projects on city-owned land and private properties in its quest to reduce runoff. While the city’s estimates suggest that the low-impact development approach will be more cost-effective than digging underground tunnels and expanding the capacity of sewage treatment plants, Philadelphia could still end up spending more than cities that followed the conventional path. But if Nutter’s plan succeeds, the city will have gained more than a network of underground sewage tunnels. Low-impact development promises to offer energy savings, create attractive green spaces, and reintroduce residents of the city to the water cycle. Only time will tell if the investment was worth the extra effort.

２０１２年纳特尔市长与环境保护署签署了一项协议。根据该协议，费城将用２５年时间来更换覆盖城市的三分之一不透水（地）表面，采用包括绿色屋顶、雨水花园、透水路面，以及其他具有低影响开发特性的措施来截留最初的２．５厘米降水^［４７］。如果一切按计划行事，费城将会在城市和私人的房地产上投资将近２５亿美元以减少径流。尽管城市的预算显示，低影响开发模式会比开挖地下“蓄水库”和扩大污水处理厂的容量更划算，费城仍然有可能比那些遵循传统方法的城市花费更多的钱。但是，如果纳特尔的计划成功的话，费城获得的将不只是地下污水管网。低影响开发模式承诺提供低能耗，创造具有吸引力的绿色空间，以及让市民重新参与到水循环中。现在，只有时间会告诉我们这项投资是否值得。

ps. I typed up the English myself, so errors are possible.

水４．０：饮用水的过去、现在与未来

［美］戴维·塞德拉克　著

徐向荣　等译    虞左俊　校

上海科学技术出版社

出版时间：2015.08

ISBN：978-7-5478-2729-1

定价：38元

Water 4.0: The Past, Present, and Future of the World's Most Vital Resource

Paperback：March 31, 2015

by David Sedlak (Author)