Estimating Regionalized Planning Costs of Green Infrastructure and Low-Impact Development Stormwater Management Practices: Updates to the US Environmental Protection Agency's National Stormwater Calculator.

Estimating regional costs of green infrastructure (GI) and low-impact development (LID) stormwater management controls is an important issue for many municipalities and water utilities in the United States. The National Stormwater Calculator (NSWC) is a site-scale, planning-level tool. A regional cost estimation methodology was recently added to the NSWC, enabling users to estimate region-specific capital and maintenance costs of commonly used GI controls. This paper discusses the approach used to estimate and regionalize costs in the NSWC.