Sustainable drainage devices for carbon mitigation

Purpose - Sustainable drainage ( SUDS) techniques seek to address problems associated with excess water quantity, poor water quality, and attempt to improve environmental quality. SUDS have also been proposed as suitable for adapting to and mitigating climate change. The purpose of this paper is to evaluate the contribution of SUDS to carbon mitigation for a local planning authority. Design/methodology/approach - Carbon sequestration rates of SUDS techniques were obtained from published literature. A Geographical Information System was used to identify potential sites for future SUDS implementation across the area covered by a local planning authority, Coventry, UK. The carbon mitigation potential of different SUDS techniques was estimated, taking account of land cover and land use limitations on new build and retrofit implementation. Findings - Vegetated SUDS in new developments and retrofit green roofs provided the greatest potential for carbon storage in this urban setting. Research limitations/implications - This study undertook a rapid assessment of the carbon mitigation that SUDS offers in an urbanised environment. The impact of factors such as greenhouse gas emissions from SUDS devices, management regimes and embedded carbon in engineered structures was not taken into account. The mitigation potential of associated shading and insulation by vegetated SUDS was not evaluated. Practical implications - Retrofit of, for example, green roofs should be prioritised to take advantage of SUDS for climate change mitigation. The relatively low level of carbon stored over a 15-year analysis period compared to the scale of forecast emissions revealed the extent of carbon mitigation challenges facing Coventry. Originality/value - This study provides a methodology to evaluate the carbon mitigation potential of SUDS in an urban setting. Current UK legislative and regulatory emphasis focuses on new build. However, retrofit approaches appear to offer greater potential for carbon sequestration.