2NDNATURE led the Reasonable Assurance Analysis (RAA) and supported development of the Green Stormwater Infrastructure (GSI) Work Plan for the Solano County, CA cities of Fairfield, Vallejo, and Suisun. The regional watershed analysis included projections of stormwater runoff, particulate pollutants and the San Francisco Bay pollutants of concern, Polychlorinated Biphenyls (PCBs) and mercury (Hg) loading for the years 2020, 2030, and 2040. Developed in tandem, the pollutant modeling analysis provided reasonable assurance that the future watershed scale public and private investment in green stormwater infrastructure meet the total maximum daily load (TMDL) waste load allocation milestones specified in the Solano County permittees municipal separate storm sewer system (MS4) permits.
The team relied heavily on 2NFORM analytics for modeling, implementation tracking, and regulatory reporting. The green infrastructure plan maps out practical and cost-effective investments in public and private nature based stormwater investments. Scenarios using different locations, sizes and types of green stormwater capture and treatment followed expected new and redevelopment patterns throughout the County. Various watershed scenarios were modeled using 2NDNATUREs peer-reviewed Stormwater Tool to Estimate Load Reductions (TELR) (Beck et al. 2017; Conley et al., 2020; Conley et al. 2021) to iteratively identify the most practical and cost-effective long term strategy for the County partners. The final green stormwater infrastructure compendium of projects were loaded into the 2NFORM Project Delivery module to provide the region with a living portfolio of planned projects that can be iteratively delivered as investment and redevelopment allows. The 2NFORM Scenario Planning module provides both the asset specific water quality performance estimates and the aggregated potential assurance that the TMDL load reduction targets will be achieved should the entire GSI Plan be implemented. They Solano permittees are able to track progress towards TMDL milestones and make informed choices as they go. This web map provides a publicly accessible summary of the key products.
