Cloudburst Management Plan - Copenhagen

The Cloudburst Management Plan is a city-wide strategy for dealing with extreme rainfall events. The strategy was adopted by the City of Copenhagen, Denmark in 2012 to complement the Copenhagen Climate Adaptation Plan adopted a year earlier. The objective of the Cloudburst Management Plan is to reduce the impact of flood events as a result of heavy rains which are expected to increase in frequency as a result of climate change. To implement the plan, the city aims to realise 300 projects over 20 years. Every year, the city decides which projects will be undertaken through a prioritisation process that ensures new projects are implemented in high risk areas, areas where measures are easy to implement, or areas where new investments can be connected to ongoing urban development projects. The plan is jointly implemented and financed by the City of Copenhagen, the Greater Copenhagen Utility Company and private actors such as private landowners.

Overview

Type of instrument:

Legislative, regulatory and strategic instruments›Sectoral strategy, plan, or law

Challenges addressed

Water management (e.g. reuse)
Flood risk: pluvial and fluvial / soil permeability

Consideration of nature-based solutions:

As part of the plan, two masterplan variations were developed to assess costs and potential advantages and disadvantages of different potential solutions. The Conventional Masterplan option focused on grey engineering solutions such as increasing the diameter of sewage pipes to funnel floodwater to the harbour. The Blue-Green Masterplan option focused on potential of nature-based solutions that store or drain excess water at ground level, such as opening streams, constructing new canals or establishing lakes and more green spaces. The Blue-Green Masterplan has turned out to be significantly more cost-effective - without even considering additional qualitative social benefits such as health, environmental, and urban spatial quality improvements. The final set of solutions chosen combines majority of nature-based solutions with piping and tunnels in those areas of the city where ground level drainage is not possible.

Targeted (peri-)urban areas:

Parks and (semi)natural urban green areas

Blue areas

Green areas for water management

Urban green space connected to grey infrastructure

Good practice characteristics:

Effective

Support multifunctional NBS

Sustainable in the long-term

Locally appropriate

Potential to be replicated / upscaled

Innovative

Governance

Government body/bodies

Initiating body:

Copenhagen City Council

Instrument design:

Details about how the instrument was designed:

The Cloudburst Management Plan developed by the City of Copenhagen was coordinated with Køben-havns Energi (Copenhagen Energy), the City of Frederiksberg, and Frederiksberg Forsyning (Frederiksberg utility company), since all rainwater falling in Frederiksberg during an extreme rainfall event leads to either a sewage treatment plant or into the sea via the City of Copenhagen. Furthermore, collaboration was initiated with neighbouring local authorities who lead surface water and waste water through the city to the common sewage treatment plants or to common water courses and lakes. An overall strategy for a public participation program was established to gauge the requirements of the citizens who would be affected by extreme rainfall events and proposed solutions. Universities, private consultancies, and industry representatives were involved in the initial hydraulic modelling underlying the strategy, testing and design solutions, strategy and budget planning as well as implementation of some of the solutions.

Involvement of non-governmental actors:

Public sector institution (e.g. school or hospital)

Private sector, corporate, business

Researchers, university

Citizens or community groups / NGOs

Type of actor involvement:

Civil society consultation through e.g. workshops, surveys

Instrument implementation:

Type of involvement:

The Cloudburst Management Plan, together with the Climate Adaptation Plan and accompanying measures aim to establish the co-sharing of adaptation between the City of Copenhagen, citizens and other private actors. The majority of relevant information is available at the city homepage for free, and the Technical and Environmental Administration also offers assistance, for example at environmental offices located in local communities in the city. The city administration has furthermore included HOFOR, the regional water company, and invited local business and clean tech companies to develop local solutions as a way to stimulate green growth and make use of local business expertise.

Type of non-governmental actors involved:

Co-design of NBS, implemented by government

Implementation of NBS (e.g. with government funds)

Targeted actors:

Public sector institution (e.g. school or hospital)

Private: household, real estate developer, business , financial

Financing

Sources of funding:

Public local authority’s budget

Corporate investment

Utility company

Budget:

Above 10 000 000€

Details about instrument financing:

Implementing the Cloudburst Management Plan is estimated to cost ca. €1.5 billion (DKK 11 billion). This sum is compared to €0.8 billion in damage costs incurred as a result of flooding in central Copenhagen in the summer of 2011 alone. The initiatives are financed by combination of public and private investments by private home owners, the city administration and the utility company via taxes and revenues from drainage charges. Surface solutions will cost an estimated €700 million (DKK 4.975 billion). The costs of municipal and the private co-financing projects will be reimbursed through water charges. Cloudburst pipes will cost an estimated €358 million (DKK 2.66 billion), covered through water charges (Greater Copenhagen Utility Company). Disconnection and connection outside property boundary will cost around €134 million (DKK 1 billion), covered through water charges (Greater Copenhagen Utility Company). Protection of homes with anti-flood backwater valves and disconnection within property boundary is estimated at around €320 million (DKK 2.4 billion), financed by private landowners.

Monitoring, evaluation and impacts

Is a monitoring framework in place?:

Did an evaluation take place?:

Achieved outcomes and impacts:

In December 2015, a list of 300 adaptation actions to be implemented over the next 20 years was endorsed by the City Council. Copenhagen was able to work with water utility on a comprehensive restructuring of the Copenhagen drainage system (including separation of rainwater from waste water) and streetscape, in order to turn roads into rivers in the case of extreme rain and direct water to outlets and retention basins. This is complemented by greenscaping, in particular through implementation of the Sustainable Urban Drainage System – building of green gardens, rooftops and bioswales to prevent rainwater from flowing directly into sewers. Adaptation policies and actions have been integrated with the city development based on strong green growth, liveable public and private spaces and a growing attention to the use of nature-based solutions while also building adaptation knowledge and skills in the local administration. In concrete initiatives, the city has established Sct Kjelds Neighbourhood as an experimental urban area where citizens, NGOs, small businesses, etc. are invited to develop local solutions for rainwater retention.

Success factors and lessons learned:

The fact that the city had experienced repeated extreme weather events, the very high negative impacts of which could be quantified by means of insurance claims has created political buy-in for change. The Copenhagen government successfully pushed for a change in national level legislation to allow the use of revenues from a water-use fee combined with private financing and revenues from taxes for investment in the water management system. Presenting the adaptation measures under the “improved city green space” frame stimulated great enthusiasm and acceptance of major, costly city infrastructure overhaul. The Copenhagen Formula (see "Achieved outcomes and impacts") adapts interdisciplinary approaches, moving away from isolated thinking. A common vision aligned engineers, hydraulic experts, GIS and information technologists, architects, planners, biologists, economists, communication specialists, and landscape architects with local citizens, investors and politicians. Public participation workshops encourage and allow citizens to actively shape their municipality's Cloudburst strategy. The insurance damage savings and the increase in real estate value are two of the highest socio-economic benefits from Cloudburst adaptation. The strategic flood masterplan is the opportunity to safeguard Copenhagen from extreme weather events, while providing the foundations for a high-quality city environment.

Sources and further information

References

List of references:

City of Copenhagen (2012), Cloudburst Management Plan. Available at: https://en.klimatilpasning.dk/media/665626/cph_-_cloudburst_management_plan.pdf

Oppla (n.d.), Cloudburst Management Plan, Copenhagen. Available at: https://oppla.eu/casestudy/18017

J. Ziersen, J. Clauson-Kaas, J. Rasmussen (2017), The role of Greater Copenhagen Utility in implementing the city’s Cloudburst Management Plan. Available at: https://www.researchgate.net/publication/317574308_The_role_of_Greater_Copenhagen_Utility_in_implementing_the_city%27s_Cloudburst_Management_Plan

EEA (2016), The economics of managing heavy rains and stormwater in Copenhagen – The Cloudburst Management Plan. Available at: https://climate-adapt.eea.europa.eu/metadata/case-studies/the-economics-of-managing-heavy-rains-and-stormwater-in-copenhagen-2013-the-cloudburst-management-plan/#cost_benefit_anchor

BASE (n.d.), Implementation of the Copenhagen "Cloudburst" Strategy (Copenhagen, Denmark). Available at: https://base-adaptation.eu/implementation-copenhagen-cloudburst-strategy-copenhagen-denmark

C40 (2016), C40 Good Practice Guides: Copenhagen - Cloudburst Management Plan. Available at: https://www.c40.org/case-studies/c40-good-practice-guides-copenhagen-cloudburst-management-plan/

Further documents

Documents:

cph_-_cloudburst_management_plan.pdf

Photos

@Atelier Dreiseitl