City and County of San Francisco - Sediment Sampling, Characterization and Disposal Consultation Services Sediment Transport Modeling

Accumulation of sand near the San Francisco Marina West Basin entrance channel
Period of Performance: 
January, 2006 to September, 2009
Project Goals: 

The City of San Francisco Marina/West Basin (Marina West Basin) is located along the northern waterfront of San Francisco within the Golden Gate National Recreation Area and adjacent to the Marina Green Park (See Site Vicinity Map below). Shoaling in and immediately bayward of the entrance channel presents a navigation hazard to boats entering and exiting the Marina. To maintain the navigable waterway, the City of San Francisco Recreation and Parks Department conducts routine maintenance dredging in areas of concern within the Marina and entrance channel. To address this ongoing navigational hazard and maintenance issue, SAIC contracted ADH to investigate and report findings on grain size data, ocean wave patterns, and records of historical sediment deposition along the Marina West Basin breakwater and entrance channel.

Project Description: 

ADH, as a San Francisco Human Rights Commission certified Disadvantaged Business Enterprise subcontractor to SAIC provided as-needed consultation services to the San Francisco Department of Public Works (DPW) from July 2006 until September 2009 for sediment characterization monitoring programs to support maintenance dredging and new construction dredging along the City’s Bay front, inland lakes and reservoirs. 

Scope of Services: 

 

San Francisco Marina, Sediment Transport Modeling: ADH and SAIC developed a conceptual model of sediment transport and deposition in and around the Marina West Basin and Channel Entrance. Sediment grain size, ocean wave patterns, and historical sediment deposition data were researched and compiled into a report for the DPW Bureau of Engineering. The conceptual model of sand deposition at the Marina West Basin is that sand is transported as wave-suspended sediment from beaches south of the outside of Golden Gate by longshore drift and deposited where the waves reach deeper water and lose capacity to keep the sand suspended. Potential alternatives for sand deposition control and maintenance were presented in this report.

San Francisco Marina West Basin Site Location

Ocean wave patterns incoming to the San Francisco Marina breakwater. Illustrates waves are likely transporting sand by littoral longshore drift to the east along the Marina West Basin breakwater and entrance channel. Source: San Francisco Marina West Basin, Sand Deposition Conceptual Model, SAIC and ADH, January 3, 2008.