Sonoma Creek enhancement project

Reviving 400-acres of wetland habitat in San Pablo Bay.

Audubon California staff at Sonoma Creek site. Photo: JoLynn Taylor

Audubon California is working with a number of partners to enhance 400 acres of tidal marsh habitat on the San Pablo Bay National Wildlife Refuge along Sonoma Creek. The project will benefit birds such as Ridgway’s Rails, Black Rails, and a number of marsh songbirds, along with the endangered salt marsh harvest mouse and native plants. Fish, such as coho salmon and steelhead, rely on healthy wetlands as habitat where juvenile fish can feed and grow.

The Sonoma Creek runs from Sonoma County into the San Pablo Bay on the northernmost end of the greater San Francisco Bay.  More than a hundred years of mining and agricultural operations have greatly limited the ecological function of these wetlands. Open water sediment from hydraulic mining during the Gold Rush caused a rapid buildup of mud flats which were subsequently turned into farmland, and maintained by levees.

In the last three decades, tidal action has reclaimed some of the area, creating stagnant wetlands that built up too fast to form natural channels. These stagnant pools form algal mats and harbor mosquitos. The remaining agricultural land has now become too salty for most agriculture, and some has been sold or abandoned.

The core of the project will involve constructing a network of tidal channels within the marsh to drastically improve tidal exchange and nutrient cycling and provide habitat to a myriad of marsh-dependent wildlife species. The channels will also provide spawning and feeding grounds for endangered and commercial fishes. Improving hydrology will improve water quality by increasing circulation and drastically reducing the amount of pesticides applied to areas  of ponded water that currently facilitate heavy mosquito production.

The project also has a vital climate change adaptation component. The construction of a gently-graded high marsh transition zone will reduce storm surge flooding of adjacent private lands and provide crucial high tide refuges for rails and small mammals.

Implementation of the project will also provide hands-on educational opportunities for students who would not otherwise experience natural history in the field setting.

Audubon California is partnering on the project with the Marin-Sonoma Mosquito and Vector Control District and the San Pablo Bay National Wildlife. Consultants for this project are Wetlands and Water Resources, Inc. and ESA Associates.  Construction is being carried out by Hanford ARC.

Designated as an Important Bird area, San Pablo Bay and its surrounding wetlands provide critical habitat for the birds of the Pacific Flyway. Birders visiting the refuge can see Brown Pelicans, White-tailed Kites, Golden Eagles, Peregrine Falcons, Common Yellowthroats, and migratory shorebirds including Whimbrels and Willets.

Funding and other support for this project has been provided by:

  • U.S. Fish and Wildlife Service - National Coastal Wetlands Conservation Grant
  • California Wildlife Conservation Board
  • National Fish and Wildlife Foundation
  • California State Coastal Conservancy
  • Environmental Protection Agency (EPA)
  • Marin-Sonoma Mosquito and Vector Control District
  • San Pablo Bay National Wildlife Refuge
  • Point Blue Conservation Science
  • Science STRAW program (Students and Teachers Restoring a Watershed)
  • Wetland and Water Resources, Inc.
  • Individual donors and volunteers

Here's the latest on the project

The hidden beauty of marshland

Before the enhancement (left), Sonoma Creek had "dead zones," where vegetation could no longer grow. Now (right), water is channelled and greenery is returning to the areas. Photo: Google Earth (left), Courtney Gutman (right)

Courtney Gutman got an aerial view of the progress made at our Sonoma Creek enhancement project which we completed in November. Gutman is our restoration project manager from the Richardson Bay Center & Sanctuary and oversaw construction on the 400-acre tidal marsh in the greater San Francisco Bay.

Within weeks of finishing the construction, the team could already see a myriad of vegetation and wildlife coming back to the area, including a variety of small shorebirds and pickleweed, a native succulent that absorbs saltwater. 

The Sonoma Creek enhancement is the first project of its kind on a pre-existing marsh. Before the project, sea water was able to wash in during high tide, but with no way for it to drain, stagnant pools became perfect breeding ground for mosquitoes and an imperfect breeding ground for plant life and other animals. To solve this problem, we dug canals to help with drainage of the area. Natural channels can now form in areas that were once stagnant, contributing to a healthier marshland. We also moved about 30,000 cubic yards of soil to create a transition ramp that slows storm surges and gives animals somewhere to go when the tide gets too high. 

Gutman says people are starting to see estuaries beyond their importance for wildlife, plants, and biodiversity.

“Now on top of that we’re seeing how important they are for combatting climate change. They’re truly our natural barriers for rising sea levels,” she says. 

For more information about the project, visit our Sonoma Creek page

Taking a tour through the new channels in Sonoma Creek Enhancement site

I took a tour of our Sonoma Creek Enhancement Project with Meg Marriott, Refuge Biologist at San Pablo Bay National Wildlife Refuge. It's hard to tell in the video but we saw Marbled Godwits, Willets, and Long-billed Curlews.

New bird species seen at Sonoma Creek Marsh

Wilson's Snipe Photo: shell game/Flickr creative commons

Yesterday was the first survey the Audubon team was able to do since construction ended at the Sonoma Creek Enhancement Project. In the marsh and along the newly formed channel during a high tide (>5’), the group counted:

  • 600 small shorebirds (Western/Least Sandpipers/Dunlin);
  • 117 Greater Yellowlegs;
  • 69 Willet;
  • 2 Long-billed Curlew;
  • 5 Black-bellied Plovers;
  • 1 Wilson’s Snipe. The Snipe was never seen in the marsh during surveys prior to construction.

Later during a ‘low’ tide, the group encountered smaller numbers of birds but spotted a rare Lesser Yellowlegs among a group of Greater Yellowlegs.

The group counted a couple of Northern Harriers scouting the area for meals, as well as a White-tailed Kite.

Birds flocking to completed tidal marsh enhancement

Construction wrapped up in November on our 400-acre tidal marsh enhancement project at Sonoma Creek in the San Pablo Bay National Wildlife Refuge, located in the northern part of San Francisco Bay. The new habitat is already attracting a lot of birds.

400-acres of important bird habitat restored in San Pablo Bay
Sonoma Creek Restoration

400-acres of important bird habitat restored in San Pablo Bay

— $3 million project will provide home for endangered species like the Ridgway’s Rail
Construction ends on Sonoma Creek enhancement project
Audublog

Construction ends on Sonoma Creek enhancement project

Our gang takes a quick tour of the enhancement project at Sonoma Creek on the last day of work

It's alive!
Audublog

It's alive!

Sonoma Creek tidal marsh works like a charm during king tide event

Peep, peep goes the Sandpiper

Least Sandpipers (calidris minutilla), utilizing newly formed channel in Sonoma Creek Marsh.

Sonoma Creek Marsh restoration update

We learn all about marsh mounds from restoration manager Courtney Gutman.

Great numbers of shorebirds at our Sonoma Creek restoration site

Audubon California's Courtney Gutman visited our Sonoma Creek restoration site last week, and found that a ton of wintering shorebirds were already enjoying one section of restored habitat. If you look closely, you can see the Northern Harrier that prompted all these birds to go on the wing.

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