RAND Corporation, Report Announcement, Oct. 26, 2020.

Urban stormwater management is a growing challenge in many U.S. cities, and climate change is expected to add to this challenge. RAND researchers apply simulation modeling and economic valuation to estimate the potential benefits and costs of a green stormwater infrastructure (GSI) system in Pittsburgh’s Negley Run watershed. The authors evaluate a series of GSI investment strategies and make recommendations for how local actors should proceed.

Key Findings

  • Negley Run already faces notable flood risk from heavy rainfall events.
  • Sewer overflow and flood risk increase with heavier rainfall from plausible future climate change.
  • A new centralized daylighted system and upstream investments could substantially reduce, but not eliminate, sewer overflows in Negley Run.
  • Scenarios with higher annual rainfall generally lead to greater sewer-overflow cost-effectiveness.
  • GSI cobenefits from the strategies evaluated could contribute substantial value to residents when accounting for uncertainty and using conservative assumptions.
  • The net economic value of the strategies considered is nearly always positive across a wide range of assumptions.

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

by Jordan R. Fischbach et al.