Capacity Down Pipe: Comparisons with Other Sustainable Drainage Systems

Abstract

Sustainable drainage systems (SuDS) design is predominantly based on expert opinion supported by descriptive guidance documents. The aim of this paper is to compare the novel Capacity Down Pipe SuDS technique in terms of its design, operation, maintenance, management and cost efficiency with other SuDS techniques. The assessment criteria are based on novel ecosystem service variables including those characterising flood and diffuse pollution control for fitting and retrofitting of key SuDS techniques particularly for the domestic housing market. The paper proposes the application of SuDS techniques that obtain high ecosystem service scores for a specific urban site. This approach contrasts with methods based on traditional civil engineering judgment linked to standard variables based on community and environment studies. For a case study area (Greater Manchester), a comparison with the traditional approach of determining community and environment variables indicates that soakaways and infiltration trenches are generally less preferred than capacity down pipes, ponds and filter strips. However, belowground storage tanks, swales and permeable pavements also received relatively high scores, because of their great potential impact in terms of flood volume control. The application of the proposed methodology will lead to changes of the sustainable drainage infrastructure in the urban landscape by promoting the novel capacity down pipe technology, which has a very low footprint and is inexpensive.