Cost-Benefit Analysis (CBA) of Sustainable Drainage Systems (SUDS) Retrofit: A Case Study

Cost-Benefit Analysis (CBA) of Sustainable Drainage Systems (SUDS) Retrofit: A Case Study

Oluwayemi A. Oladunjoye David G. Proverbs Beck Collins Hong Xiao

School of Engineering and the Built Environment, Birmingham City University, UK

Available online: 
| Citation



The retrofit of Sustainable Drainage Systems (SuDS) has been applied successfully to properties to help mitigate future flooding and to deliver other benefits to properties, such as improvements in air and wa- ter quality, economic benefits and improved business reputation. However, the uptake of SuDS retrofit has been low due to a lack of understanding of the true costs and benefits and concerns about long-term maintenance. This study presents a cost-benefit analysis (CBA) of the monetary and non-monetary val- ues of SuDS retrofit in the context of an individual property, in this case, a leisure centre. A qualitative study was carried out comprising a series of interviews with stakeholders to the property, an analysis of documentary evidence and observations on the site. The findings demonstrate the importance of teamwork amongst the stakeholders during the decision-making process in helping to overcome many of the known challenges. The willingness to pay process is used to value the tangible and intangible benefits arising from the scheme. The installation would provide a net value to the client of well over £100,000 over a 10-year period versus the installation costs of £39,000 and the return on investment would be achieved in just 3 years. The findings highlight many of the apparent barriers that need to be overcome when installing retrofit schemes and clearly demonstrate the importance of the intangible benefits derived. It is recommended that these are given full consideration at the decision-making stage and in supporting the uptake of the retrofit of SuDS.


SuDS retrofit, flood, leisure centre, costs, benefits and maintenance


[1] Webber, J. L., Fu, G., & Butler, D., Comparing cost-effectiveness of surface water flood management interventions in a UK catchment.  Journal of Flood Risk Management, e12523, 2019.

[2] Pitt, M., Learning lessons from the 2007 floods (p. 505). London: Cabinet Office, 2008.

[3] Abubakar, A. M., Elrehail, H., Alatailat, M. A., & Elçi, A., Knowledge management, decision-making style and organizational performance. Journal of Innovation & Knowledge, 4(2), 104-114, 2019.

[4] Brinkmann, R., Interconnections in Environmental Sustainability: Water and Energy. In Environmental Sustainability in a Time of Change (pp. 195-216). Palgrave Macmillan, Cham, 2020.

[5] Jha, B., Cueto-Felgueroso, L., & Juanes, R., Fluid mixing from viscous fingering. Physical review letters, 106(19), 194502, 2011.

[6] Oladunjoye, O. A., Proverbs, D. G., Collins, B., & Xiao, H., A cost-benefit analysis model for the retrofit of sustainable urban drainage systems towards improved flood risk mitigation. International Journal of Building Pathology and Adaptation, 2019.

[7] Lamond, J. E., Rose, C. B., & Booth, C. A., Evidence for improved urban flood resilience by sustainable drainage retrofit. Proceedings of the Institution of Civil Engineers Urban Design and Planning, 168(2), 101-111, 2014.

[8] Oladunjoye, O. A., Proverbs, D. G., Collins, B., “The barriers and opportunities to the retrofit of sustainable urban drainage systems (SuDS) towards improving flood risk mitigation in urban areas in the UK”, International Sustainable Ecological Engineering Design for Society (SEEDS) Conference: Conference Proceedings, Leeds Sustainability Institute, pp. 420-431, 2017.

[9] Stovin, V., Poë, S. and Berretta, C., “A modelling study of long term green roof retention performance”, Journal of Environmental Management, Vol. 131, pp. 206-215, 2013. DOI: 10.1016/j. jenvman.2013.09.026.

[10] Chambers, D., Spaenjers, C., & Steiner, E. (2019). The Rate of Return on Real Estate: Long-Run Micro-Level Evidence. Available at SSRN 3407236.

[11] Lloyd, P., Sustainable Urban Drainage Systems (SUDS): a proactive approach to reducing surface flooding, 2019.

[12] Castleton, H. F., Stovin, V., Beck, S. B., & Davison, J. B., Green roofs; building energy savings and the potential for retrofit. Energy and Buildings, 42(10), 1582-1591, 2010.

[13] Walsh, C. J., et al, Principles for urban stormwater management to protect stream ecosystems. Freshwater Science, 35(1), 398-411, 2016.

[14] Carboni, D., Gluhak, A., McCann, J.A. and Beach, T.H., “Contextualising water use in residential settings: a survey of non-intrusive techniques and approaches”, Sensors, Vol. 16 No. 5, p. 738, 2016.

[15] Roelich, K., Financing infrastructure and built environment adaptation to climate change. University of Leeds, 2015. 24 Oluwayemi A. Oladunjoye et al., Int. J. Environ. Impacts, Vol. 4, No. 1 (2021)

[16] Sustainable Development Commission, The future is local: empowering communities to improve their neighbourhoods, 2010.

[17] Joseph, R., Proverbs, D., Lamond, J., & Wassell, P., Application of the concept of costbenefit analysis (CBA) to property level flood risk adaptation measures. Structural Survey, 2014.

[18] Domínguez, I., Ward, S., Mendoza, J. G., Rincón, C. I., & Oviedo-Ocaña, E. R., Enduser cost-benefit prioritization for selecting rainwater harvesting and greywater reuse in social housing. Water, 9(7), 516, 2017.

[19] Cimato, F., & Mullan, M., Adapting to climate change: analysing the role of government. Defra Evidence and Analysis Series, Paper, 1, 2010.

[20] Yang, F., Tan, J., & Peng, L., The effect of risk perception on the willingness to purchase hazard insurance—A case study in the Three Gorges Reservoir region, China. International Journal of Disaster Risk Reduction, 101379, 2019.

[21] Kuhlicke, C., et al, Multiple flood experiences and social resilience: findings from three surveys on households and companies exposed to the 2013 flood in Germany. Weather, climate, and society, 12(1), 63-88, 2020.