Delivering and Evaluating Multiple Flood Risk Benefits in Blue-Green Cities
University of Nottingham

WP4. Evaluation and Synthesis of Benefits

Many attempts have been made in the literature to measure and value the multiple benefits of green infrastructure but the results are often regionally specific (and not UK focused), relate to specific concerns (e.g. climate change), and are based on a disparate set of tools and methods. 

This background information needs assembling in ways which can provide practical advice to designers, planning authorities and other urban flood risk management (FRM) stakeholders, so it can be incorporated into formal decision making procedures.   


  • Develop/apply primary procedures for the robust evaluation of the multiple functionalities of Blue-Green infrastructure within urban FRM strategies and to assess the inherent uncertainties

  • Develop methodologies for evaluating the relative significance of benefits in context specific locations, and establish preference ratings linked to a multi-criteria analysis for component selection

  • Review current design procedures and make recommendations to the design guidance to enhance the most significant non-flood benefits (e.g to enhance water quality improvement)

Photograph of SuDS scheme in Newcastle, UK.Photograph of a SuDS scheme in NewcastlePhotograph of a SuDS scheme in Newcastle

Potential Benefits of Blue-Green Infrastructure

  • climate change adaptation and mitigation
  • reduction of the urban heat island effect
  • better management of stormwater and water supply
  • carbon reduction/mitigation
  • improved air quality
  • increased biodiversity (including the reintroduction and propagation of native species)
  • habitat enhancement
  • water pollution control
  • public amenity (recreational water use, parks and recreation grounds, leisure)
  • cultural services (health and well-being of citizens, aesthetic, spiritual)
  • community engagement
  • education
  • attractive landscaping and quality of place
  • increased land and property values
  • economic growth and investment
  • labour productivity (stress reduction, attracting and retaining high quality staff)
  • tourism
  • products from the land

 Images left SuDS scheme in Newcastle, UK.



  • New protocols to help practitioners understand the relevant dominant benefits for a SuDS/GI scheme to complement existing monetisation techniques (e.g.CIRIA BeST tool) through the following new concepts:
    • Benefit profile – using normalised benefit values against a defined initialcondition state
    • Benefit intensity – the spatial distribution of cumulative benefits
    • Benefit dependency – the interrelationships between benefit categories andtheir response to a set of site specific controlling variables 

  • A Blue-Green Cities Multiple Benefits Toolbox to evaluate the spatial distribution of six biophysical benefits (flood damange mitigation, access to greenspace, carbon sequestration, air pollution reduction, noise pollution reduction and habitat size). 

  • Hoang L, Fenner R, Skenderian M. A Conceptual Approach For Evaluating The Multiple Benefits Of Urban Flooding Management Practice. Journal of Flood Risk Management, 2016. DOI: 10.1111/jfr3.12267. Access article here

Key Findings

  • Spatial distribution of multiple benefit intensity from SuDS/GI can usefully inform aspects of urban planning

  • The wider benefit performance of SuDS/GI installations is dependent on the initial condition of each site location

  • Tradeoffs may occur between different benefits categories for a range of installation types, and the benefits and dis-benefits are context specific

  • Many benefits are incremental and need to be assessed in relation to the rate they develop over time, so the benefit profile also distinguishes between realised and potential benefits in each category

The WP4 team comprised Dick Fenner, Lan Hoang and Malcolm Morgan (University of Cambridge), and was supported by Emily O'Donnell (University of Nottingham). 

Blue-Green Cities Research Project

Sir Clive Granger Building,
University of Nottingham,
University Park,
Nottingham, NG7 2RD.

Tel. 0115 8468137