Improving Urban Resilience: the Blue- Green Advantage

Transcription

1 Improving Urban Resilience: the Blue- Green Advantage Image credit: Arup Dr Emily O Donnell emily.o donnell@nottingham.ac.uk CIBSE Resilient Cities Group Meeting 21st March 2016 bluegreencities.ac.uk EPSRC Grant EP/K013661/1

2 Develop and rigorously evaluate strategies for managing flood risk that deliver multiple benefits as part of urban planning and renewal

3 Blue-Green Cities Working with nature to manage water and deliver a range of other benefits to society, the economy and the environment Multifunctional landscape Blue-Green space connectivity

4 Traditional drainage (grey infrastructure)

5 London without the Thames Barrier during the December 2013 tidal surge (Environment Agency simulation) Source: agazine

6 The challenge Future risks Increasing stress on subsurface grey infrastructure due to; 1. expansion of impermeable surfaces in urban environments (economic + population growth) 2. increased rainfall due to climate change

7 December January Rainfall Anomaly Source: ce.gov.uk/climate/u e.gov.uk/climate/uk/ k/summaries/2014/ summaries/2015/de january cember

8 what is required is a fundamental change in how we view flood management, from flood defence where we protect ourselves to one of resilience, living with and making space for water and the opportunity to get more from less by seeing all forms of water as providing multiple benefits. Commission of Inquiry into flood resilience of the future titled Living with water, March All Party Group for Excellence in the Built Environment, House of Commons, London SW1A 0AA: p. 32.

9 The opportunity Philadelphia Water Department, Green Infrastructure Vision Source:

10 Bioswales (green streets) source control

11 Treatment trains also help with sediment detention

12 Eco-roof (green roof)

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14 (less blue-green) Blue-Green infrastructure

15 Downspout disconnections

16 Model Existing Flood Risk Management Model Citizens Behaviours Evaluate Multiple Flood Risk Benefits Stakeholder and Community Communications Options for Hard/Soft Measures Demonstration Case Study

17 Uncertainties, challenges and barriers Downscaling climate projections Impacts of climate change Biophysical Uncertainty Asset maintenance and performance Capital costs Multiple benefits of BGI Responses to CC impacts Sociopolitical Uncertainty Public preferences Stewardship of BGI Natural hazards Modelling Interagency working Population Climate change Economic resilience to CC Urban/ economic development Socio-political uncertainties, e.g. public preferences, stewardship and equitable delivery of BG assets, have a greater impact on decision making than biophysical uncertainties

18 The Newcastle Learning and Action Alliance Blue-Greening the urban core a master-planning workshop

19 Source: lelive.co.uk/news/n orth-eastnews/newcastlehelps-lead-wayblue Impact and Feedback

20 Model Existing Flood Risk Management Model Citizens Behaviours Evaluate Multiple Flood Risk Benefits Stakeholder and Community Communications Options for Hard/Soft Measures Demonstration Case Study

21 Evaluating the multiple benefits of Blue-Green infrastructure

22 GIS Multiple Benefits Toolbox Openly available to download from:

23 GIS Multiple Benefits Toolbox Current benefits that the GIS toolbox can evaluate: Flood damage mitigation Access to Greenspace Air Pollution trapping Carbon Sequestration Habitat Size Noise Pollution attenuation

24 Model Existing Flood Risk Management Model Citizens Behaviours Evaluate Multiple Flood Risk Benefits Stakeholder and Community Communications Options for Hard/Soft Measures Demonstration Case Study

25 Flood inundation modelling: CityCAT Water depth map of Ouseburn catchment (120 km 2, 2 m cell size, 30 million cells, 60 min storm event, 100-yr return period)

26 Flood inundation modelling: Wingrove Arthurs Hill, Wingrove Permeable pavements + back-alleys + green gardens can help reduce surface water for small rainfall events

27 Model Existing Flood Risk Management Model Citizens Behaviours Evaluate Multiple Flood Risk Benefits Stakeholder and Community Communications Options for Hard/Soft Measures Demonstration Case Study

28 Community behaviours and preferences Local People are the local experts - with useful knowledge People value Blue-Green assets - if they understand them People will help maintain the Blue-Green assets they value People need to feel ownership to make BG solutions work People must be engaged prior to and throughout implementation

29 Other key outputs Sediment transport modelling: a 2D hydro-morphodynamic model has been developed to predict flow and suspended sediment dynamics in urban rivers and investigate how restored floodplains and SuDS ponds can attenuate the upstream flood peak, act as a sediment sink and impact on downstream sediment transport Sediment, debris and ecosystems: detailed understanding of how Blue-Green infrastructure treats fine sediment and key urban pollutants during multiple rainfall-runoff events has been developed (focus on fine sediment detention and resuspension) A Flood Footprint damage accounting framework has been developed to measure the total socio-economic impact that is directly and indirectly caused by a flood event. This can be used to optimise investment in Blue-Green infrastructure by identifying the blind- spots in critical infrastructure and vulnerable sectors in economic supply chains and social networks.

30 Concluding remarks Blue-Green Cities work with nature to manage water and deliver a range of other benefits to society, the economy and the environment. The landscape is designed to be multifunctional, and added value is placed on Blue-Green space connectivity to increase the net benefits and make them more than the sum of their parts. Key Blue-Green Cities Outputs: Uncertainty and communications Flood inundation modelling Sediment transport modelling Sediment movement through SuDS Public perceptions and behaviours Flood footprint Multiple benefit evaluations Download: egreencities.ac. uk/bluegreenciti es/documents/b lue-green-citieskey-projectoutputs.pdf

31 Thank you for your attention, any Acknowledgement questions? The research reported in this presentation is being conducted as part of the Blue-Green Cities Research Consortium with support from the: Engineering and Physical Sciences Research Council Northern Ireland Rivers Agency Environment Agency National Science Foundation City of Portland Bureau of Environmental Services bluegreencities.ac.uk EPSRC Grant EP/K013661/1