Crissy Field Coastal Lagoon Restoration
The historic 127-acre tidal marsh and coastal lagoon at Crissy Field was filled nearly a century ago during construction of the Panama Pacific International Exposition and later used as an airfield. It has been transformed into a popular public waterfront park featuring 14 acres of restored coastal lagoon that serves as a focal point for visitors to San Francisco's Presidio.
ESA provided planning and design services to restore Crissy Field wetlands. The need to preserve historic cultural resources and public access limited the size of the restored wetland to 14 acres. Unlike previous tidal habitat restoration projects around San Francisco Bay, large amounts of wave-driven sands are naturally deposited along the site's shoreline. A key design consideration was whether the wetland produces enough tidal scour to maintain an open connection to the Bay, or if deposition of beach sands at the mouth of the inlet would periodically close the entrance channel.
ESA monitored Crissy Field's evolving beach-inlet-lagoon system for seven years following restoration. We used the monitoring data to develop a quantified conceptual model of inlet closure and breaching. This model was applied to predict how often the inlet would need to be excavated (breached) mechanically versus the reduction in breaching requirements with a larger wetland. These methods are being applied at other inlets to guide management actions.