A Systematic, Multi-Criteria Decision Support Framework for Sustainable Drainage Design Jo-fai Chow, Dragan Savić, David Fortune, Zoran Kapelan, Netsanet Mebrate You can download this presentation from chow-ccwi chow-ccwi2013 photo's courtesy of

About this Presentation Background Green Values of Drainage Systems Evaluation Framework Maximising Multiple Benefits Conclusions 02 of 15slides

Background Trends in Drainage Industry Moving towards a sustainable approach Challenge Lack of commonly agreed standard for sustainable drainage design Objective To develop a new decision support system for sustainable drainage design Collaboration EPSRC, STREAM IDC, University of Exeter and XP Solutions 03 of 15slides Sustainable & Balanced Approach Traditional & Biased Approach Water Quantity Water Quality Other Benefits Water Quantity Water Quality

Why Sustainable Drainage Design? Green Values of Drainage Systems Water Quantity Runoff reduction, flood risk mgt., re-use Water Quality On-site treatment Environmental Impact Cleaner water & air, amenity, biodiversity, recreation, community Energy Saving Less cooling/heating, reduced carbon footprint Green Image of Business 04 of 15slides photo's courtesy of XP Solutionsphoto's courtesy of ReneCreate photo's courtesy of EMPowerHouse photo's courtesy of roanokeoutside.com photo's courtesy of nzconservation.wordpress.com photo's courtesy of Arup photo's courtesy of Polypipe photo's courtesy of gregwalcher.wordpress.com photo's courtesy of china.org.cn photo's courtesy of Deloitte

Quantifying Green Values: From Good Feelings to Real Numbers 05 of 15slides Calculations based on previous research projects and case studies. For more information : 1.Conference Paper greenvalues 2.This presentation online (tinyurl.com/ greenvalues )

Using physical attributes & location of infrastructures to calculate costs. Four main categories of performance measures. Key performance indicators (KPIs) calculated for each infrastructure. Calculate monetary measures of benefits based on KPIs. Consider costs and benefits over the design life of systems. Putting the Numbers Together: A Systematic Evaluation Framework 06 of 15slides Information from a typical drainage model.

Using the Framework – Inputs: Components in a Drainage Design Model 07 of 15slides Bioretention Permeable Paving Wetland Swale photo's courtesy of XP Solutions

Using the Framework – Outputs: Operational and Capital Expenditure 08 of 15slides Swales are relatively cheap to build and maintain. Question: can the costs be justified? Permeable paving costs a lot more to build and maintain.

Using the Framework – Outputs: Key Performance Measures 09 of 15slides Permeable paving can effectively reduce runoff via infiltration … but it does not add amenity value to the community. At a fraction of the cost, swales can provide moderate runoff reduction and increase the amenity value as a result of the green surface areas. Goal: moving away from subjective opinions to evidence- based comparison.

Comparing Different Approaches: Green (Sustainable) vs. Grey (Traditional) 10 of 15slides Bioretention Permeable Paving Bioretention Wetland Swale photo's courtesy of allbiz Storage Tank Question: is it worth considering the green approach after all? What do you think? Let’s consider the sustainable design example discussed in previous slides again. What if we replace the swales and wetland with storage tanks?

Comparing Different Approaches: Green (Sustainable) vs. Grey (Traditional) 11 of 15slides Green approach can provide multiple benefits in addition to water management. Green approach costs about the same to operate, much less to build yet a lot more for the land occupied when compared to grey approach. In this case, the framework suggests similar long-term costs for both approaches. (Let me repeat the key message again…) Goal: moving away from subjective opinions to evidence-based comparison.

Comparing Multiple Drainage Design Options 12 of 15slides Different design options.Comparing multiple benefits with parallel coordinates. Comparing cost-benefits for different options.

Next Step: Beyond Evaluation - Maximising Multiple Benefits 13 of 15slides Design Consideration: Legislative Requirements Location Sizing Type & Order Identifying Trade-offs: Multiple benefits Multi-objective optimisation ? ? ? ? ? ? photo's courtesy of University of Sheffield photo's courtesy of XP Solutions photo's courtesy of BME Imaging photo's courtesy of bfrss.org.uk

Conclusions 14 of 15slides Challenges: lack of commonly agreed standard for sustainable drainage design. Aim: to develop a new decision support system. Why green infrastructures? Because they can offer multiple benefits in addition to water management. Quantifying green values with KPIs and monetary measures. A systematic evaluation framework - evidence-based comparison, a better tool for optioneering. Integration with multi-objective optimisation – encourage the consideration of multiple benefits. Research outputs for industrial sponsor: new features in their drainage design software suite. “Essentially, all models are wrong, but some are useful.” – Professor George E.P. Box photo's courtesy of Amazon

Thank you for your attention 15 of 15slides Any questions? Many thanks to Prof. Dragan Savić who kindly agreed to present this for chow-ccwi chow-ccwi2013 greenvalues greenvalues xpdrainage xpdrainage

Additional Information: Capital and Operational Expenditure Extraslides

Additional Information: Estimation of Annual Reduced Runoff (m 3 ) Extraslides

Additional Information: Annual Energy Savings Extraslides

Additional Information: Amenity Value of New Habitats Extraslides