An Alternative Compliance Framework for Stormwater Management in the Central Coast Region

Urbanization modifies watershed hydrology, increases stormwater runoff, and impacts the quality of receiving waters. The Central Coast Regional Water Quality Control Board (CCRWQCB) will be requiring hydromodification control and Low Impact Development (LID) for certain new development and redevelopment projects as part of their “Post-construction Stormwater Management Requirements for Development Projects in the Central Coast Region” (PCRs) for Municipal Phase I and II Stormwater NPDES permits. Compliance with PCRs revolves around the use of structural and non-structural LID stormwater control measures (SCMs) and numerical performance-based criteria. An alternative compliance (AC) approach provides off-site compliance options when on-site compliance may be infeasible. Flexibility in meeting compliance is often desired by a municipality in order to have a venue to allow developers proposing a development project to pay the municipality a sum of money to implement stormwater controls at a different location within the watershed, and to support the optimization of stormwater management, community development, and natural resource protection within a watershed. Municipalities in the Central Coast Region should develop AC programs as PCRs may necessitate the need for off-site mitigation to achieve compliance. The purpose of this report is to assist municipalities in meeting state and federal hydromodification and water quality control requirements by synthesizing the legal, environmental, technical and socioeconomic considerations of alternative compliance and developing a framework to create AC programs. Additionally, the report summarizes findings from a planning-level case study conducted with the City of Watsonville to evaluate the feasibility aspects of alternative compliance