Managing Heavy Rainfall with Green Infrastructure: An Evaluation in Pittsburgh’s Negley Run Watershed

RAND researchers use simulation modeling to evaluate present and future risks in Negley Run watershed in Pittsburgh from sewer overflows and flooding given future rainfall uncertainty. The authors then evaluate proposals for a phased series of green stormwater infrastructure (GSI) investments. In addition to estimating stormwater benefits and implementation costs, the authors provide economic estimates of recreational, amenity, and other cobenefits to local residents; compare total benefits to costs; and explore potential trade-offs. Results show that a centralized system of stormwater management in Negley Run could yield cost-effective sewer-overflow reduction, reduce street flooding, and provide positive net economic benefits across a range of assumptions about future rainfall and implementation costs.