Are Neighborhood-level SUDS Worth it? An Assessment of the Economic Value of Sustainable Urban Drainage System Scenarios Using Cost-Benefit Analyses

Abstract

Sustainable urban drainage systems (SUDS) offer solutions to water quality and quantity problems in stormwater management in urban areas in addition to numerous economic benefits in terms of urban ecosystem services. Cost-benefit analyses (CBA) of individual SUDS measures, such as green roofs and living walls, are investigated, but economic analyses of complete SUDS for neighborhood-level application are still missing. CBA of neighborhood-level SUDS applications can inform practitioners and decision makers for the proper assessment of planned stormwater management projects. This paper estimates the benefits and economic value of urban ecosystem services of SUDS for a neighborhood in Berlin, Germany, and compares these to typical cost estimates found in literature. Benefits quantified include both private and social benefits. Three separate SUDS scenarios with different combinations of measures for the same district are compared in terms of their net present values (NPV), benefit-cost ratio (BCR) and benefit and cost efficiencies. Parameters of the NPV analysis are also analyzed in a sensitivity analysis. Our results show positive NPVs and BCRs above 1 for one scenario in an analysis of private benefits. Inclusion of social benefits yields only slightly improved NPVs and BCRs. Overall, we demonstrate economic feasible SUDS for stormwater management.