DU, Partners Reintroduce Tidal Waters to California Refuge

Earlier this year, Ducks Unlimited and its partners returned tidal waters to approximately 1,285 acres of California's San Pablo Bay National Wildlife Refuge (NWR)-an area known as Cullinan Ranch. This project has produced incredible results, with thousands of waterfowl beginning to utilize the area almost immediately after the effort was completed.

Part of Island Number 1 on many historical maps, Cullinan Ranch was the first island in the North Bay (part of San Francisco Bay) to be reclaimed for agriculture. In the 1880s, a levee was constructed around the edge of the island to exclude tidal waters. The site was drained and farmed for oats and hay until the 1980s, when it was nearly developed into a residential marina community. The U.S. Fish and Wildlife Service (USFWS) purchased the property in 1991 with the goal of restoring the area to tidal marsh habitat and managing it as part of San Pablo Bay NWR.

The USFWS partnered with DU to conduct the restoration work necessary to accomplish this goal. Construction began in September 2011 to prepare the site prior to breaching the perimeter levee. DU and USFWS staff constructed a flood-control levee along a low stretch of Highway 37 and a transitional-slope levee to protect the remaining 2.3 miles of highway, which included installing lightweight geofoam blocks to prevent settlement, gradual slopes to dissipate wave energy, and riprap to create surface roughness. New acceleration and deceleration lanes were installed to provide access to newly constructed amenities at the west end of Cullinan Ranch, which include a 1.5-mile walking trail, a kayak launch, and a wildlife observation platform.

The first of three levee breaches was kicked off during a project dedication ceremony in early 2015, returning tidal waters to Cullinan Ranch for the first time in over 100 years. The event celebrated the project and all the partners who have worked so diligently since the 1980s to bring it to fruition. More than 100 people attended the dedication, including Paul Bonderson Jr., who has since been elected DU's 43rd president; members of the media; local citizen groups; legislative officials and their representatives; project supporters; and DU and FWS staff.