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Watsonville Slough Estuary Restoration, Section 1135 (CAP)

map showing green land, blue water, and white mountains


The Watsonville Slough is located in Santa Cruz County, California. It is a tributary of the Pajaro Lagoon, where the Pajaro River meets the Pacific Ocean. Land use practices and the Federal levees in the project area have decreased the size of Watsonville Slough, limiting tidal marsh and coastal wetland habitat that is vital to native fish, bird, and wildlife species. Together, the levees and land use have isolated Watsonville Slough from surface fluvial processes and overland flows. Further, natural hydrology of the slough would normally include backwater flooding from a closed-lagoon period, when the sand bar blocks the mouth of the Pajaro River and the lagoon water levels rise, inundating the marsh plain.  However, the local county must breach the lagoon during high water events because a critical access road is flooded, leaving residents stranded and disconnected from emergency access. This mechanical breaching of the lagoon truncates the natural hydrology of the marsh, and habitat zones that would normally be inundated during lagoon closures are drained quickly, leaving them “high and dry.” This CAP 1135 study is working to improve the quality and function of tidal marsh and coastal wetland habitat by restoring a more natural hydrologic regime. Multiple measures are being modeled to assess their influence on marsh inundation, including construction of tidal channels, lowering berms between the slough and marsh plain, and raising a road crossing to reduce the need to manually breach the lagoon. Specifically, the project seeks to restore hydrology to the upper marsh, expanding the range of healthy marsh.

            TOTAL FUNDING

            TOTAL COST                                                                             $  14,440,000

            FEDERAL COST                                                                         $  10,320,000

            NON-FEDERAL COST                                                               $     4,120,000


            TOTAL FEDERAL COST THROUGH FY 2022                         $        925,000

            FY 2023 BUDGET                                                                     $        450,000   

            COST TO COMPLETE                                                               $     8,945,000


  • The project team kicked off the feasibility study and leverage planning charettes to gather insights from key project stakeholders to move efficiently through the early planning steps.
  • Project team leveraged “Engineering With Nature” planning strategies to assess meaningful ecosystem restoration benefits associated with a road raise.


  • Extensive hydrologic modeling supporting ecosystem benefits of measures (December 2022)
  • Tentatively selected plan milestone (20 April 2023)
  • Release of draft report for public, policy, agency review (summer 2023)


  • The TSP will likely include a road raise that will increase the tidal prism extent within the marsh while improving emergency access during high water events. Comprehensive benefits are being used to evaluate the alternatives on ecosystem, safety, and other benefit categories.
  • Sea level rise is anticipated to affect the project area.


  • 19th District, Rep. Jimmy Panetta


  • Deputy for Project Management, (415) 503-6593.

Updated on 15 February 2023