Sea Level Rise Scenarios

To ensure SLR adaptation is approached consistently across Marin County’s numerous cities, special districts, and other jurisdictional boundaries, project staff recommend the use of the BayWAVE scenarios for local vulnerability assessments and adaptation plans. It is important that the approach taken by individual cities, land management agencies, utility districts, and other relevant entities addressing SLR are compatible as adaptation challenges are shared throughout the county, and infrastructure spans administrative boundaries.

The USGS’s Coastal Storm Modeling System (CoSMoS) was selected to model the sea level rise countywide. It can be viewed through the Our Coast, Our Future (OCOF) website. The following six scenarios are used to model near-, mid-, and long-term sea level rise, with and without the 100-year storm.

BayWAVE Scenarios from CoSMoS
Near-term: 10 inches (25 cm), no storm 10 inches with 100 year storm
Mid-term: 20 inches (50 cm), no storm 20 inches with 100 year storm
Long-term: 60 inches (150 cm), no storm 60 inches with 100 year storm

BayWAVE’s scenarios are consistent with state level guidance. In March 2013, the State of California adopted the 2012 National Research Council Report Sea-Level Rise for the Coasts of California, Oregon, and Washington. This report identifies projected SLR for 2030/near term as 2-12 inches (4-30 cm), 2050/medium term as 5-24 inches (12-61 cm) and 2100/long term as 17-66 inches (42-167 cm).

Download Guidance for Sea Level Rise Models & Scenarios.

Sea Level Rise Model Comparison Memo

For more information on BayWAVE, visit