The economic impacts of green stormwater infrastructure: An evaluation of novel stormwater management policies in Washington, D.C.

Abstract

Increases in urban stormwater infrastructure needs have led cities around the world to turn towards nature-based ‘green’ stormwater infrastructure (GI). While GI can be an effective tool for addressing many urban flooding and water quality problems, many policymakers remain skeptical of GI due to concerns about financial uncertainties and performance risks. Moreover, cost-benefit analyses of changes to urban infrastructure policies often fail to consider the economic impacts – jobs created and value added to the regional economy – of infrastructure (traditional or GI) construction. Compounding this, few studies have modeled the economic impacts of GI. In this paper, we analyze the economic impacts arising from novel development regulations requiring GI to offset impervious cover expansion in Washington, D.C (USA). Using data from a survey of GI construction firms, we determine annual, direct GI investment, and construct an input-output model to estimate indirect and induced economic impacts at the regional scale. We find that, from 2015 to 2020, GI construction supported over $91 million in average annual economic output, ∼$45 million in labor income, ∼$60 million in value added, and created (or supported) 437 jobs in the DC metropolitan region. Sensitivity analysis around regulatory stringency (higher or lower stormwater retention requirements) reveals asymmetric economic impacts that increase more given higher retention requirements than they decrease for lower retention requirements. Our analytical approach can serve as a model to help other regions produce a more comprehensive accounting of the economic feasibility of green infrastructure for urban stormwater management.