SAN PABLO BAY AND MARE ISLAND STRAIT
OPERATIONS AND MAINTENANCE

PROJECT LOCATION AND DESCRIPTION

San Pablo Bay and Mare Island Strait, which are located in Solano County, California, provide deep-water access to the Suisun Bay Channel and the Ports of Sacramento and Stockton. This project provides for maintenance dredging of (1) a 600-foot wide channel to a depth of 35 feet Mean Lower Low Water (MLLW), which is approximately 11 miles long, in San Pablo Bay across Pinole Shoal with a maneuvering area adjacent to Oleum Pier at the mouth of Carquinez Strait; (2) a 600-foot wide channel to 30 feet MLLW through Mare Island Strait, flaring to a turning basin generally 1,000 feet wide, from former dike number 6 to within 75 feet south of the causeway between Mare Island and Vallejo; (3) a channel to 30 feet MLLW up the Napa River, except (4) at the northerly end, at the City of Vallejo Marina, where the project depth is 26 feet MLLW.
 

FY23 ACCOMPLISHMENTS

• Funds will be used for O&M dredging of Pinole Shoal Channel with the Government Dredge Essayons.
• Project is an annual hopper dredging site scheduled to be dredged every other year.  In FY22, it was not scheduled for dredging to allow dredging at Richmond Outer Harbor. 
• The SPB channel dredging is not planned for FY24, as it is performed biannually in odd number years, so will be performed in FY23, and scheduled again for FY25.

FY24 ACCOMPLISHMENTS

• Annual condition survey conducted on the channel.
• Planning and design level of effort performed in preparation for the FY25 dredging episode.

ISSUES AND OTHER INFORMATION

• The Port of Stockton and Contra Costa County are the Non-Federal Sponsors (NFS).
• Maintenance dredging of Mare Island Strait was last performed in 1994.
• With the closure of the Mare Island Naval Shipyard, the channel is no longer maintained at authorized project depth for deep draft vessels.
• In 2015, the City of Vallejo requested a Section 216 evaluation of the Mare Island strait section of the project to support resumption of maintenance dredging to - 30’ depth after a multi-year lapse. The report was completed by Aug 2016 and sent to the sponsor.  No further planning to resume dredging Mare Island straight as taken place since that report.
• Periodic surveys will be performed to monitor the rate of shoaling on Mare Island Strait.
• New consistency determination request to have a range of volumes from 150,000 CY to over 600,000 CY to cover the dry and wet year.
• The SF Bay Regional Water Quality Control Board has included requirements in our Water Quality Certification that have resulted in limiting hopper dredging to a single in-bay project each year.  Currently, there are two in-bay projects that were previously hopper-dredged annually – Richmond Outer Harbor and San Pablo Bay (Pinole Shoal).  This new requirement results in the two projects having to alternate dredging each year.  In FY24, Richmond Outer will be deferred.

CONGRESSIONAL INTEREST

• 8^th District, Rep. Johan Garamendi

POINT OF CONTACT

• Deputy for Project Management, Thomas R. Williams, 415-503-6560

Updated on 29 February 2024

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