哥本哈根城市排水防涝规划URBAN DRAINAGE & WATERLOGGING PREVENTING PLANNING, COPENHAGEN

项目类型：战略性洪水规划

项目位置：丹麦哥本哈根市

项目规模：3400ha

设计公司：安博·戴水道

翻译：张旭

Project Type: Strategic Flood-Controlling Planning

Location: Copenhagen, Denmark

Size:3,400ha

Design Firm: RAMBOLL STUDIO DREISEITL

Translated by Zhang Xu

德国戴水道设计公司和安博国际工程集团于2013年共同制订了哥本哈根排水防涝规划，这个案例展现了在面临气候变化的丹麦首都在最新一轮城市规划中如何将“海绵城市”设计与城市排水防涝和水系规划相结合，打造丰富且有效的蓝绿基础设施。该案例同时展示了城市规划在明确街道暴雨管理指标、统筹绿地空间、生物空间和水利空间等方面，如何采用战略可行的方法。该项目在2013年赢得了国际知名的设计奖项INDEX设计奖。

背景

作为全球最可持续的城市的哥本哈根位于气候变化前沿，近些年来遭受了越来越多的暴雨袭击。从2010年8月至2011年8月一年间，哥本哈根市遭受了3次暴雨袭击，主要公路及城市基础设施被淹。2011年7月2日全市大面积区域遭受严重洪涝灾害侵袭，暴雨淹没了城市中心区域大部分的城市街道和地下空间。最初的经济学分析指出，如果不采取任何措施，在未来的一百年间由于气候变化引起天气的剧烈变化造成暴雨事件的破坏力将造成3倍的损失。以此事件作为城市创新设计的契机，哥本哈根决定制订综合的气候适应型策略以保护城市，暴雨管理规划方案便由此而生，它在保护城市有能力抵御未来的暴雨事件的同时，为哥本哈根提供更多的蓝绿空间，增加城市的生物多样性并为市民提供更多的休闲空间。

水文

该暴雨管理规划计划在未来30年间完成，它充分考虑了气候变化可能带来的极端天气情况，以保护哥本哈根市抵御百年一遇的暴雨侵袭。应对百年一遇的暴雨，该规划可容纳城市道路雨水10cm高度的提升，且计划分担城市排水系统30%～40%的雨水泄流，这样的指标设定是针对气候变化导致的极端暴雨预期增加的40%的降雨量。该暴雨管理规划完全建立在简单的原则之上，要点在于将雨水蓄留于地面之上进行管控，而非增加地下管道升级改造的高昂费用。

哥本哈根市被划分为8块区域，针对各不同集水区进行具象化的规划。安博国际工程集团联合德国戴水道设计公司参与了其中4块区域的规划设计，针对街道、蓄留街道、绿色街区进行了丰富和细致的分析，形象地阐释了规划设计方案如何支撑城市的总体规划目标，为市民增加宜居安全感和舒适度。多功能的空间设计是具象化规划的关键因素，例如，公园和广场在暴雨时可为泄洪场地，而在旱季则可充当市民的休闲娱乐空间。在人口密集和空间稀缺的都市里，这些多功能的空间在99%的时间里供游乐和休闲之用。

海绵手段

哥本哈根城市由两个行政部分组成：哥本哈根和腓特烈斯贝。过去30多年以来，安博国际工程集团一直在规划和设计城市污水处理基础设施系统以及为城市服务的两家废水处理厂。工作的目标即完全控制污水的排放，实现污水的全部处理，营造拥有优良水质条件的港口和海岸环境。也因如此，哥本哈根市已经拥有详细的各区位水利基础设施的数据，并借助综合的计算机建模预测进入两家废水处理厂的雨水及其径流以及雨水溢流至溪流和港口的流量。2011年的暴雨事件也恰巧为该数据模型提供了实际检验机会。

基于已有信息和模型计算，哥本哈根暴雨管理规划得以开展。以腓特烈斯贝行政区为例，在气候适应框架之下进行的暴雨管理规划重点关注城市的低洼部分，确保未来城市开发的可能性，并建设可持续性的排水基础设施，以保证暴雨期间洪水水位10cm以下。该战略规划基于以下三个原则：

（1）在高地势地段滞留雨水，以保护低洼地段的安全。

（2）在低洼区域采用可靠灵活的雨水径流排放方式。

（3）在此低洼区域进行雨水径流管理。

通过这些战略规划，热点区域被确定下来，一系列暴雨管理规划项目在兼顾考虑其他城市规划目的的前提下也被确定下来，如此暴雨规划之中各项目便与交通基础设施改善规划及城市更新规划相整合。

腓特烈斯贝暴雨管理规划项目包含以下要素：暴雨街道规划、滞留街区规划、中央滞留带规划（公园和广场）、绿道规划、传统暴雨排水管道规划。

腓特烈斯贝林荫道下方的地下通道供暴雨期间的雨水排放之用。作为哥本哈根城市之中景色优美、具有历史意义的林荫路，它的美丽景色以及功能发挥受到车辆停靠的挑战。该林荫道的重新设计包含增大步行道路面积，并将停车区域设置于地下的两条通道之中。在遭遇大雨之时，这些通道可作为泄洪场地。在暴雨时节，雨水从中央绿带流向街道，进而随街道坡度变化流向建筑体，对于建筑底部排水管道排水压力的缓解毫无帮助。

安博公司设计的道路模板是改变整体的道路特征，形成V字形道路，在道路中央的绿带中创建大容量的雨水蓄留空间。在下雨之时，雨水从周边的房屋和街道流向该绿色空间，这种在暴雨之时产生的“城市河流”能够容纳每秒3300m3的雨水量。在常规降雨和干燥季节时，该低洼的绿带同样可作为周边市民休闲娱乐的场所。

中央滞留区域同样是该暴雨管理规划的核心元素。一项全新的建议即通过降低湖内的水位，将哥本哈根三大内城湖泊之一的圣乔治湖转变为海滨公园。在湖岸区域，一处新型的公园将被建造，提供休闲场地，例如散步和慢跑道路，一片可享受晴朗天气日光普照的草坪以及一个嬉水游乐场。新建公园将有效提升生物多样性指数并有效调节环境微气候。汇入湖体的水质将被提升，以改善湖体的生态特性。一处新广场将建于天文馆对面，一个次级街道的绿化带也被包含在内。该公园在暴雨期间被淹没用于泄洪。如此，便形成了收集雨水的庞大空间，并提升了城市的休闲价值。通过这种以休闲娱乐结合雨水排放的方式比通过建造体量巨大、费用昂贵的暴雨排水管道来转移50万m3预期的雨水的方式节约近1.34亿欧元用于建造地下雨水管道的费用。

效益

哥本哈根暴雨管理规划以及同系列的项目设计计划的通过首先经由严格的审查和讨论过程，然后进入优先考虑程序以及决策阶段。正如哥本哈根的其他规划和建设项目，该过程包含所有相关的市政利益相关者的参与，并允许公众意见的反映。安博公司为此决策审核通过的过程进行了详尽的成本效益评估。这个评估权衡了在例如资金以及新设施的运营之中投入与收益的关系：它能够保护城市抵御洪水侵袭，增加的绿地空间可降低空气污染，降低对于现存下水系统改造的费用投入，提升房产价值。2015年有几百个具体项目获批，招投标已经开始进行。

社会经济学分析结果显示，这种关注提升城市整体宜居性的设计所产生的费用大大超越了其建造和维护的费用。尽管在30年的时间中需要投资13亿欧元的费用，它在预防城市洪涝灾害和降低损害方面的收益将大大超越其投资。这一案例展示了长效、全面、可持续的城市问题解决模式，并可作为世界上其他同样面对此类问题城市的规划范本。哥本哈根市采用此种方式抵御气候变化，能够得到社会经济方面的诸多益处。

哥本哈根暴雨管理规划展示了在一个多学科团队之中各传统专业跨专业合作的需求。水利工程师与建模专家合作，以便管理复杂的水利以及工程水利系统之中的技术局限。景观设计和规划师在项目之中提供全新的蓝绿城市环境设计，而经济学家则提供决策过程之中所需要的成本效益评估。哥本哈根暴雨管理规划能够提升城市的可持续性，并为城市提升其环境质量、保障居民生活品质、确保城市长期的弹性适应能力和经济增长趋势增添重要的元素。

Studio Dreiseitl and RAMBOLL International Engineering Group collaborated in compiling the urban water drainage & waterlogging preventing plan. This case demonstrates how to combine the sponge urban design with urban drainage & waterlogging preventing planning in the latest round of Danish urban planning, and how to how to construct extensive and effective blue and green infrastructure in the face of climate change. This case illustrates how to adopt strategic and feasible approach following the cleared streets stormwater management indicators on the balanced green space, biological space and hydraulic space integration. The project has won the internationally renowned INDEX Award in 2013.

Background

As the world's most sustainable city, Copenhagen is in the forefront in terms of the climate change. In recent years the city has experienced a growing number of storm events. From the August of 2010 to the August of 2011, Copenhagen was attacked by three heavy storm, major highways and urban infrastructure were submerged. A large area of the city severely suffered from the flooding disasters on July 2nd, 2011. Storm flooded most of the city streets and underground space in the central urban area. The initial economic analysis pointed out that if no measures ware taken, the devastating storm result from dramatic climate change would cause three times the damage in the next one hundred years. This event has been perceived as an opportunity for an innovative urban design, Copenhagen decided to develop comprehensive climate-adaptive strategies to protect the city. The stormwater management plan was produced in this context. It has the ability to prevent the city from future damage caused by storm, and it is capable to offer more blue-green space. Meanwhile, it could increase urban biodiversity and provide more recreational space for citizens as well.

Hydrology

The plan of stormwater management is expected to be accomplished in the next 30 years, which fully takes the extreme weather conditions caused by climate change into account, it can protect Copenhagen against the heavy rains of once a year. In order to be efficiently responsive to the once a hundred years'rain, the plan could accommodate 10cm lifted rainwater level on the streets, and it supposed to share and dispose 30%～40% volume of the rainwater discharged by the urban drainage system. The determination of the project'indexes base on the extreme storm precaution, in which is forewarned of the increased 40% amount of precipitation cause by the climate change. The stormwater management plan is entirely on the basis of a simple principle, the main point is that the controlled rainwater should be retained or detained on site, rather than increasing the already highly cost to upgrade or reconstruct the underground pipeline networks.

Copenhagen is divided into eight regions. For every water catchaent areas, a figurative design was delivered. Ramboll International Engineering Group and Atelier Dreiseitl cooperated on the planning & design for four regions. They comprehensively and carefully analyzed the roads, retention streets and green neighborhoods, and illustrates how could the detailed plan & design be supportive to purpose of the master plan vividly, and enhanced the sense of comfort and security for the citizens.Multipurpose space design is a key factor to these figurative planning, such as parks and plazas could be used as the flood discharge area during heavy rains and remained the public recreational space in the dry season. In the densely populated and space deficient city, these versatile spaces will be used for entertainment and leisure purposes in 99% of the time.

Sponge measures

Copenhagen city is composed of two administrative parts: Copenhagen and Frederiksberg. Over the past 30 years, Ramboll Engineering Consultant Firm has been planning and designing the urban sewage treatment infrastructure systems and two wastewater-treatment plants which serve the city. Objectives of the systems are to control the sewage water discharge and to realize the full treatment of sewage water, and to create the ports with excellent water quality and pleasant coastal environment. It is also the reason why Copenhagen already have the detailed data of all the water infrastructure in each region, and using the synthetic computer modeling to predict the volume of the rain and runoff which flow into the two treatment plants and the volume of the overflow which discharged into the streams and the ports. And the 2011 storm event also happened to provide a real opportunity for conducting a test for the statistics model.

The stormwater management plan in Copenhagen can successfully be undertaken mainly because of the available information and the modeling calculations. In Frederiksberg Administrative Region, for example, implementing the stormwater management under the framework of the climate adaptation, the plan should focus on low-lying parts of the city, the remained headspace to reserve and conserve the possibility of future urban development, and the construction of sustainable drainage infrastructure to ensure the flood elevation is beneath 10cm in the circumstance of heavy storm. The strategic planning based on three principles, shown as follows.

(1) Retain rainwater in the high-lying area, to protect the security of the low-lying areas.

(2) Establish a reliable and flexible stormwater runoff discharge system in the low-lying area.

(3) Implement stormwater runoff management in the sub low-lying areas.

Through these strategic planning, the sensitive areas were identified, a series of stormwater management planning projects were determined under a balanced consideration of other specialized planning as a prerequisite, so as an example, the improvement of transportation infrastructure and urban renewal plan were integrated in the stormwater management planning.

Frederiksberg stormwater management planning project consists of the following elements: stormwater management street planning, stormwater retention block planning, central retention zone planning (parks and squares), greenway planning, traditional stormwater drainage planning. Frederiksberg Avenue-stormwater management street design & planning. The underpass beneath Frederiksberg Avenue was designed as a discharge channel of rainwater during heavy rains. As one of the most scenic, historic avenue in Copenhagen, the vehicle parking challenged its beautiful scenery and function exerting. In the re-design of Frederiksberg Avenue, the greenway's walking paths area will be enlarged, the parking lot will be set in the two underground channels. When the rains are heavy, these channels could be used as flood venue. In wet season, rainwater will flow trough the central green belt to the street, and delivered to the building following the slope variation on the streets, and played little role in relieving the drainage pressure in the bottom of the building.

The modular street model designed by Ramboll Group has changed the overall features and characteristics of the roads, forming a V-shaped path, creating large volume of rainwater retention & detention space in the middle of the green belt on the roads. When it rains, the rainwater from the surrounding roofs and streets can flow into these green spaces. The URBAN RIVER resulted from heavy rains can accommodate and contain 3300 cubic meters per second amount of rainwater. In the condition of regular rain and dry season, the low-lying greenbelt can also be used as entertainment places for the surrounding citizens.

Central retention region is also a core element for the stormwater management planning. A new proposal is to transform St. George Lake into a waterfront park by lowering the water level in the lake. St. George Lake is one of the three great inner city lakes in Copenhagen. In the lakeshore area, a new park will be designed and built to provide leisure venues, such as walking, jogging path. One can enjoy the sunny weather on sundrenched lawn. A paddling playground is also available. The new park will effectively enhance the index of biodiversity and can be efficiently regulated microclimate in this environment. The quality of the water imported to the lakes will be improved, in expect to promote the ecological characteristics of lakes. And a new plaza will be built opposite to planetarium, the green space design on a secondary street are also included. The park will be submerged during heavy rains play a role in the function of flood drainage. So, this formed a large space to collect rainwater, and also improved the recreational value of the city. In the anticipation of transfer 500,000m3 rainwater by creating the large scaled and highly expensed stormwater drainage network combined with the entertainment and recreational function, in this approach it could saved nearly 134 million Euros of reconstructing underground municipal sewer system instead.

Effectiveness

Copenhagen stormwater management planning and a series of related project design planning will first go through the rigorous process of review and discussion, and then enter the program-prioritizing and decision-making stage. Exactly like other planning & construction projects in Copenhagen, the process will involve in all the relevant municipal stakeholders to participate in and allow public opinions to be reflected. Ramboll Engineering Consulting Firm has prepared a detailed cost-benefit assessment for the decision approval during the review process. For instance, this assessment weighed in the budget of income & expenses from the financial investment and new facilities operation. It can protect the city against flooding, alleviate air pollution due to the increase of green space, and reduce the cost of the existing sewer system renovation in return to improve the properties'value. Hundreds of specific projects were approved in 2015. Bid and tender work has begun afterwards.

Social economic analysis shows that the benefits and profits from this kind of project design, which dedicated in promotion of the urban livability, are far beyond the cost of its construction and maintenance. Despite the need of injecting totally 1.3 billion Euros into the project in the following 30 years, the cost of investment could barely compare to the effectiveness yield from the urban flood & waterlogging preventing and the damage & lost minimizing. This case shows a long-term, efficient, comprehensive and sustainable solutions to urban issues, and can serve as a model in dealing with similar problems in other area worldwide. Just like Copenhagen combat climate change in this way, and obtain many benefits in social and economic aspects.

Copenhagen stormwater management plan demonstrated the necessity of multi-disciplinary collaboration among a traditional professional team. The hydraulic engineers cooperated with the latest modeling experts to break through the bottleneck constraints in facing with the management of the complex hydro engineering and hydraulic techniques. Landscape architects and urban planners put forward a brand new blue & green urban environment design for the projects in joint efforts, and economists provide the cost-benefit assessment required by the evaluation and decision making process. Stormwater management planning in Copenhagen can enhance the sustainability of the city and promote the quality of its environment, safeguard the citizens'living standards, ensure long-term flexibility of the city's adaptive capacity, and stimulate and fuel economic growth of the city.