Reflections on Green Infrastructure Economics

Because green infrastructure used for urban storm-water management also serves larger ecosystem services functions (such as providing habitat, recharging aquifers, and minimizing erosion), proponents of these management strategies tend also to value these ancillary functions in making a case for their use when compared to conventional urban storm-water collection and detention approaches. Recent research, however, suggests that green infrastructure strategies are cost-effective when compared to conventional storm-water management approaches, even when evaluated in terms of their direct costs and savings over their useful lives. Problems with using more indirect methods of valuation include unnecessary complexity, analytical asymmetry, and distributional distortions. A case can therefore be made that assessing only the direct economic savings of green infrastructure over conventional storm-water infrastructure may be more persuasive for public policy purposes than valuing the more speculative indirect benefits in cost-benefit and cost-effectiveness analyses of green compared to conventional storm-water management strategies.