Giacomini Wetlands Restoration, USA

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For hundreds of years the south end of Tomales Bay was a productive wetland regularly visited by egrets, herons, and shorebirds in search of their favorite food found in the mudflats and tidal marshes that edge the bay. In the 1800s, settlers came to West Marin and built ranches and farms on the rich grasslands and productive prairie found in coastal areas. They created one of the premiere dairy industries in the San Francisco Bay Area. Logging ventures thrived on the virgin Douglas-fir and redwood forests along the coast in areas such as Inverness Ridge and in the wetter inland areas. Roads and a railroad carrying lumber and farm products to San Francisco resulted in the diking of extensive portions of historic marsh, converting them either to upland or to freshwater marshes and other types of wetlands.

An extensive tidal marsh complex once spanned the entire width of the headwaters of Tomales Bay, extending south towards Bear Valley and north towards Inverness. In the early 1940s, Waldo Giacomini with the help of the US Army Corps of Engineers diked the south end of Tomales Bay to create additional pasture for his dairy in order to produce milk for the war effort. More than 550 acres or 50% of the wetlands in Tomales Bay were diked to reclaim this marsh that, at that time, was thought to be an unproductive wasteland. From this land, the Giacominis created one of the largest and most productive dairies in Marin County, which the family maintained until recently.

The Giacomini Wetlands Restoration Project restored the approximately 550 acres of tidal wetlands at the head of the Tomales Bay. The National Park Service (NPS) and Point Reyes National Seashore Association (PRNSA) lead a collaborative effort to raise funds and execute the project along with several local, state, and federal partners. Funding came from several sources including The California Coastal Conservancy, Caltrans, National Fish and Wildlife Fund, SWRCB, Us Fish & Wildlife Service, the Gordon and Betty Moore Foundation, and the Wildlife Conservation Board.

There are five creeks that drain into the Giacomini Wetlands project site: Fish Hatchery, Bear Valley, Olema, Lagunitas, and Tomasini. Salmon that have been inhibited from using some of these creeks by culverts, tidegates, and other impediments will be able to swim upstream more easily and spawn in the upper portion of these smaller watersheds. They will also have more marsh channels to use during their outstream migration in preparation for adjustment to life in the ocean. Federally endangered tidewater goby, which prefer slower-moving, more impounded brackish waters, will benefit from improved habitat quality with elimination of dredging, runoff of manure into waters, and other agricultural management practices. Habitat for the elusive California black rail, a state-listed threatened species, will dramatically increase.

The project included the following restoration tasks:

  • Removal of approximately 14,000 feet of existing earthen levees
  • Lowering of approximately 1500 feet of existing levees
  • Excavation of approximately 10,000 feet of new tidal channels
  • Tidewater goby pond habitat enhancement
  • California Red-legged Frog habitat creation (Tomasini Triangle ponds, Olema Marsh ponds)
  • High tide refugia creation for Clapper and Black Rail
  • East Pasture manure scraping and infrastructure removal
  • Marshplain enhancement
  • Lagunitas Creek Floodplain enhancement and terracing
  • Demolition and removal of water control structures
  • Non-native plant species removal
  • East Pasture excavation and restoration of manure disposal pastures and ponds
  • Olema Marsh channel enhancements to restore connectivity to Bear Valley Creek

 

Work at the site was generally limited to between June and October due to environmental constraints and restrictions which proved to be a challenge for construction. Ongoing biological monitoring and related activities were performed at the project site during construction. In addition other work activities were being performed simultaneously with the major restoration work including invasive plant removal, native plant revegetation, and removal of PG&E power lines.

One of the many benefits of the project includes improvement in the quality of Tomales Bay’s waters. This could have tremendous benefits not only for people who use the estuary for recreation and oyster mariculture, but also for the freshwater, estuarine, and marine wildlife species that use Tomales Bay for breeding or foraging. Because of its importance to wildlife, Tomales Bay is not only part of the Golden Gate Biosphere Reserve and a California Critical Coastal Area, but in 2002, it was nominated as a “Wetland of International Importance” under an international treaty called the Convention on Wetlands (commonly known as the Ramsar Convention). Tomales Bay is also one of 16 wetland areas that qualify for inclusion as a wetland of regional importance under the Western Hemisphere Shorebird Reserve Network because of its large number of wintering and migrating shorebirds.

We provided project management and construction management services beginning with the 50% design stage of Phase I in May 2007. In addition to these critical management services, GHD provided the design for the demolition of the Giacomini Dairy facility in Point Reyes Station, including a survey for hazardous materials such as lead and asbestos. GHD also provided a structural assessment of an existing bridge across Tomasini Creek. During the two construction phases, GHD also provide public outreach services and assisted the NPS with updates to a project website.

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