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McNabney Marsh:

McNabney Marsh

Many people drive by McNabney Marsh (formerly known as Shell Marsh) every day without recognizing its importance as wildlife habitat. Though nestled between a busy Interstate freeway, a railroad, an oil refinery, a sewage treatment plant, a chemical plant, and a small community, researchers have concluded that it is one of the most productive wetland systems in the Bay Area, providing food and shelter for a wide variety of fish, mammals, birds and invertebrates. Thanks to the tireless efforts of a number of public agencies and private citizens, McNabney Marsh is now a thriving success story. However, in 1988, it very nearly ceased to exist.

History—Created in 1880’s when a major railroad was constructed through the area. When our story begins in 1988, plans were underway to develop the site for industrial uses.

Late in the evening of April 23, 1988, a tank at the Shell Manufacturing Complex, filled with hundreds of thousands of gallons of San Joaquin crude oil, began to leak. A hose designed to drain water from the roof of the tank failed and began to siphon oil out into the containment area surrounding the tank. Unfortunately, a storm water release valve had been left open, and the oil continued to drain into a nearby creek, under the freeway, and down into what is now called McNabney Marsh.

The Spill--Oil filled the 100-acre marsh to a depth of more than four inches before flowing under the railroad tracks, past the refinery and chemical plant, and finally out into the Carquinez Strait, upstream into Suisun Bay, and, on the next tide, downstream into San Pablo Bay.

Due to darkness, it took a while before anyone noticed the spill and a while longer to figure out where it had come from. Workers at the Shell wharf were the first to recognize and report oil on the water. They didn’t know at first that it had come from a leaking tank on their own property. Before the source of the spill could be located and stopped, about 400,000 gallons of heavy crude oil had leaked out into the environment.

Great Blue Heron - McNabney Marsh

Cleanup--Many federal, state and local agency personnel, oil company representatives, cleanup contractors, scientists and others responded to the spill. They used skimmers, oil booms and sorbant materials to recover as much oil from the surface of the water as possible. Next cleanup of residues on shorelines began. Pump trucks sucked pooled oil from the marsh, and a legion of Shell workers spread and retrieved sorbant boom, pom-pom and pads. Cleanup of waterfront areas in Martinez and Benicia involved the use of high-pressure water washing to mobilize deposited oil and sorbant pads to recover it.

Drained Pond--The McNabney Marsh was ultimately drained, and contaminated vegetation was cut and removed by small crews using hand tools.

Once oil is released, damage is inevitable. Not all of the spilled oil can be recovered, as it disperses on water and land. Even oil that is recovered causes damage before its removal. Damages include direct effects on fish, wildlife, and plants, damage to habitat and to recreational areas.

As the cleanup proceeded, people started to think about how to undo the damage. After any significant spill, there are claims for recovery of damages. Resolution of such claims can drag on for years in the courts, delaying resource restoration. In this case, all the federal, state and local agencies agreed to proceed together with a consolidated claim. In April 1990, Shell offered about $20 million to settle all of the claims in a single consolidated state and federal action.

Shell Oil Spill Trustee Committee-- The settlement included almost $11 million to restore damage to natural resources, under the direction of a Trustee Committee established by the court.

Acres Recovered and Restored--Over the next 11 years, the Trustee Committee funded and contributed to a number of projects to restore the damages of the spill and to protect and enhance fish and wildlife resources and recreation in the areas of the spill.

Because the marsh was the most heavily oiled area during the spill, the Trustees gave special consideration to restoring and enhancing this marsh. In 1992, the Trustees funded purchase of the marsh and uplands for $3,000,000. The upland areas complement the habitat values of the marsh and allow for establishment of transition habitat and a buffer zone, and also provide space to enable public viewing and interpretation of the marsh.

Great White Heron - McNabney Marsh

East Bay Regional Park District completed the acquisition and is managing it in partnership with the Mt. View Sanitary District and other trustee agencies in accordance with the fish and wildlife values of the area.

The goal for restoration of the marsh is to create a brackish marsh by returning salt waters from the Bay to the marsh. Such flows have been absent from the marsh for many years, because of water control structures built along the shore. The marsh receives about two million gallons per day of freshwater discharge from the Mt. View Sanitary District, and parts of the marsh are beginning to develop plants more characteristic of freshwater marshes. Tidal action would allow the marsh to retain its estuarine vegetation and species.

To restore tidal flows into the marsh, the Trustees supported the installation of a set of innovative tide gates that allows water and fish to enter and exit the marsh at various times during each tidal cycle. These are installed next to a chemical plant at the mouth of the outlet of the marsh. Downstream of the tide gates, the San Francisco Bay Regional Water Quality Control Board has restricted use of the gates until contaminants in slough sediments have been removed or capped.

An advisory group, consisting of various resource agencies and other interested parties (including representatives of MDAS), is meeting to formulate a plan for the realignment of nearly a mile of Peyton Slough and mitigation for the wildlife which well be disturbed by the construction. There is some disagreement among the parties as to the target species and the type of habitat to be created. However, if the various parties are able to agree on a compromise plan, construction should occur in 2003.

Al McNabney--The protection and restoration of the marsh are a legacy of many individuals and organizations. One who played a key role in these actions was Al McNabney. As a representative of Mt. Diablo Audubon Society, Al was a tireless advocate of preservation of the marsh, attending many meetings and writing many letters to draw attention to the beauty and values of the area. When it was acquired, he turned to working to ensure that public education and access would be part of the design for the area. He was instrumental in obtaining funding for interpretive elements to be built there. As a memorial to him and to commemorate his efforts, the marsh was renamed McNabney Marsh.

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