PWA - Project Detail - Crissy Field Coastal Lagoon Restoration

Title

Crissy Field Coastal Lagoon Restoration

Project Summary

This multi-objective project restored a 14-acre National Park System coastal lagoon. . PWA designed, and routinely monitors, the site, which is largely influenced by wave-driven sand transport inside San Francisco Bay.

Location

Presidio, San Francisco, CA

Client

Golden Gate National Recreation Area, Golden Gate National Parks Conservancy, and the Presidio Trust

Project Detail

San Francisco’s Crissy Field, once a 127-acre tidal marsh, was filled in during construction of the 1915 Panama Pacific International Exposition. It later became an airfield as part of the Presidio military installation. In the 1990s, Crissy Field was converted to a public waterfront park that features 14 acres of restored wetland. Since breaching in 1999, Crissy Field has evolved into a dynamic, in-bay coastal lagoon that serves as a focal point for visitors to the San Francisco Presidio.

The physical design of the wetland restoration was challenging. Unlike previous tidal wetland restoration projects around San Francisco Bay, large amounts of wave-driven sands are deposited along the site’s shoreline. The need to preserve cultural resources and public access limited the size of the restored wetland. A key design consideration was whether the wetland would produce enough tidal scour to maintain an open connection to the Bay or whether the entrance channel would close due to excessive deposition of beach sands at the mouth of the inlet.

PWA continues to monitor the evolving beach-inlet-lagoon system. An analysis of inlet dynamics was conducted to assist in planning possible expansions of the existing tidal wetland. As part of the study, a new tool was developed to predict the frequency and duration of inlet closures based on the physical processes that govern inlet stability.

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Title		Crissy Field Coastal Lagoon Restoration
Project Summary		This multi-objective project restored a 14-acre National Park System coastal lagoon. . PWA designed, and routinely monitors, the site, which is largely influenced by wave-driven sand transport inside San Francisco Bay.

Location		Presidio, San Francisco, CA
Client		Golden Gate National Recreation Area, Golden Gate National Parks Conservancy, and the Presidio Trust

Project Detail		San Francisco’s Crissy Field, once a 127-acre tidal marsh, was filled in during construction of the 1915 Panama Pacific International Exposition. It later became an airfield as part of the Presidio military installation. In the 1990s, Crissy Field was converted to a public waterfront park that features 14 acres of restored wetland. Since breaching in 1999, Crissy Field has evolved into a dynamic, in-bay coastal lagoon that serves as a focal point for visitors to the San Francisco Presidio. The physical design of the wetland restoration was challenging. Unlike previous tidal wetland restoration projects around San Francisco Bay, large amounts of wave-driven sands are deposited along the site’s shoreline. The need to preserve cultural resources and public access limited the size of the restored wetland. A key design consideration was whether the wetland would produce enough tidal scour to maintain an open connection to the Bay or whether the entrance channel would close due to excessive deposition of beach sands at the mouth of the inlet. PWA continues to monitor the evolving beach-inlet-lagoon system. An analysis of inlet dynamics was conducted to assist in planning possible expansions of the existing tidal wetland. As part of the study, a new tool was developed to predict the frequency and duration of inlet closures based on the physical processes that govern inlet stability.