Advancing climate resilience in US cities through green infrastructure by leveraging their dual roles as regulator and regulated under the US Clean Water Act

Abstract

U.S. cities face significant threats from climate change that demand aggressive adaptation measures, and yet there is neither a federal requirement that cities engage seriously with climate adaptation nor a dedicated federal effort to support such engagement. This absence may be viewed as a failure of federal policymaking, but it is also consistent with a fundamental tenet of U.S. law that land use decisions that relate to climate resilience–like sewer infrastructure and land use planning–are local issues to be left to local decision-makers. At the same time, cities are regulated themselves as sources of pollution under federal environmental statutes. These features of U.S. law collide in the case of municipal sewer systems that collect and treat stormwater. The varied municipal entities responsible for those wastewater systems–referred to as Combined Sewer Systems (CSSs) and Municipal Separate Storm Sewer Systems (MS4s)–are regulated under particular Clean Water Act (CWA) programs. Municipal compliance with those requirements focuses on cities' infrastructure planning and is often tied inextricably to cities' rules governing local land use decisions, which are primary drivers of stormwater volumes and patterns, and the attendant runoff-borne pollutants, sewer system failures, and flooding. The CWA, therefore, constrains municipal entities in their capacities as both regulated and regulator. Federal implementation of the CWA to promote better local land use decision-making could drive municipal governments toward improved climate resilience by promoting practices that can mitigate the effects of more extreme precipitation patterns and urban heat effects. Over the past two decades, cities in the U.S. and elsewhere have become increasingly interested in "Green Infrastructure" (GI) approaches–features that mimic natural processes to retain stormwater while delivering other social and environmental benefits. This chapter examines this dual role of cities under the CWA and proposes federal regulatory approaches that could leverage the existing CWA frameworks to accelerate the deployment of GI and advance municipal climate resilience.