NBS solution managing run-off in cities Bruno Tisserand EurEau President

Transcription

1 NBS solution managing run-off in cities Bruno Tisserand EurEau President NBS Tallinn 25 October 2017

2 Overview ~Who we are ~Setting the scene ~NBS and urban planning ~Case studies ~How to make it a success?

3 1. Who is EurEau? EurEau the voice of Europe s Water sector since 1975 Our members are the national water services associations from 29 We represent public and private drinking and waste water services Employing 542,000 people, the sector makes a significant contribution to the European economy European countries

4 1. What do we do? ~ We provide a network for our members to share knowledge and ideas, exchange best practices, analyse common problems and develop effective solutions. ~ We highlight the fundamental role that water services play in society. We develop positions of the water sector at EU level and we engage with EU policy makers to respond to the challenges shared by our members.

5 2. Setting the scene ~ 3 Million km of sewer pipes across Europe ~ A vast majority is combined sewers ~ Climate change influences the rainfall patterns ~ More frequent ~ More intense ~ Urbanisation increased all over Europe ~ More urban run-off to manage: CSOs and flooding

6 3. NBS and urban planning ~ Objective: to reduce run-off volume and flow peaks ~ Nature-based solutions provide: ~ Infiltration system ~ Delay of the run-off ~ Green area in cities ~ Storage capacity ~ Complementary measures to heavy grey infrastructures that provide short-term retention capacity ~ Real time control may optimise the whole system

7 3. NBS and urban planning ~ Multiple solutions available ~ Green roofs ~ Detention and retention ponds ~ Infiltration trench ~ ~ Publication of a guide available on European Commission website: http\:nwrm.eu/urban

8 3. NBS and urban planning ~ Examples of natural water retention measures: 1. Green Roofs 2. Permeable surfaces 5 3. Swales 4. Channels and rills Filter Strips 3 6. Soakaways Infiltration Trenches 8. Rain Gardens 8 9. Detention Basins Retention Ponds 11. Infiltration basins

9 4. Case studies ~ Copenhagen ~ Malmö ~ Thessaloniki ~

10 Nature based solutions Case: Copenhagen October 2017 Jes Clauson-Kaas, HOFOR, Greater Copenhagen Water Utility

11 Denmark and Copenhagen : new climate legislation in DK - possible for utilities to finance surface solutions (Natural based solutions). - An evaluation (May 2017) of projects under this regulation shows that these solutions are ¼ of traditional underground pipe solutions. - 1,1 billion DKK against 4 billions DKK for traditional underground pipe solutions.

12 Green roads

13 Rain garden

14 CLOUDBURST STORAGE IN CENTRAL PARK

15 Local square made green 15

16 Green retention in city centre 16

17 Malmö ~ 6km of canals and water channels and 10 retention ponds. ~ Rainfall is collected in natural ditches and reservoirs before directed into a conventional sewer system ~ landscape features are integrated into the townscape which also provide recreational green spaces ~ Green roofs implementation ~ 90% of the stormwater into the open storm-water system. ~ total annual runoff volume reduced by 20% due to evapotranspiration from channels and retention ponds between the rain events. ~ runoff peak flows are delayed and attenuated.

18 Thessaloniki ~ Through European Integrated Cooperation Programme Integrated Green Cities ~ Development of a model for sustainable design and redesign of urban spaces: urban green oriented ~ Improvement of the infiltration capacity of the city through redesign of the Chrimatistiriou square to make it a bioclimatic tool (trees, fountains ) ~ Reduce run-off during rain-events and decrease temperature during hot summers. ~ Combined with a real time information system to help management of the sewer

19 4. Case studies ~ Copenhagen ~ Malmö ~ Thessaloniki ~ And also many others ~ Strasbourg, Lyon, Paris region, Bordeaux, Brussels ~ The design knowledge is available, is it enough? ~ Efficiency has to remain over years!

20 5. How to make NBS a success? ~ Political will at local level (too often driven by extreme events don t wait for next time) ~ Public awareness is key ~ Integration and long-term vision for urban planning ~ Directives can be a driver (WFD, FD, BWD, UWWTD) especially with the coming evaluations ~ Investment is needed, but generally less than for big retention tank, and more visible to the public ~ Maintenance to keep the full capacity of the infrastructures between rainfall events should remain under public responsibility

21 6. Conclusion ~ Sustainable management of urban run-off needs integration of NBS solutions in urban planning to ~ Reduce the peak flow ~ Reduce the run-off volume ~ Adaptation to climate change option ~ Need for local level acceptance and long-term urban planning ~ Need for anticipation and investment ~ Maintenance under public responsibility

22 Thank you for your attention With the strong support of Bertrand Vallet: Rue du Luxembourg 47-51, B-1050 Brussels, Belgium Tel: +32 (0) Fax: +32 (0) BE www. www.