The first phase of this project enhanced approximately 120 acres of perennial marsh. Phase II completes restoration of the marsh and established a “low drain” connection with San Diego Creek at Creek elevation and then excavated an area inside the Lower Marsh. At this lowered elevation, estuary water that historically entered the Lower Marsh will again be able to do so, with plans to establish (or allow colonization by) salt marsh habitat. This is part of the long term vision of mitigation for sea level rise in the existing salt marsh at the San Joaquin Marsh site.
The project includes a feasibility study, conducting environmental review, consulting with permitting agencies, and preparing final construction designs and contract documents for Phase II of San Joaquin Marsh Reserve restoration. The 1997 Revised San Joaquin Marsh Enhancement Plan recommended that restoration of the marsh proceed in two phases. Phase I, which the Coastal Conservancy funded and is largely complete, encompassed enhancement of seasonal ponds and restoration of coastal sage scrub habitat (Exhibits 2 and 3). Phase II would focus on enhancement of the approximately 120 acres of perennial marsh.
The feasibility study evaluates alternatives to increase and maintain open water areas within the perennial marsh. Historically, the perennial marsh contained open water areas and channels. The extent and depth of the open water areas has significantly decreased due to gradual accumulation of sediment and organic matter and subsequent encroachment of cattails. Except for a few remaining open water areas, the marsh has become predominantly a monoculture of cattails. Consequently, the loss of open water habitat has reduced the diversity of wildlife species that the San Joaquin Marsh Reserve supports.