Local Habitat Catagories:
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.
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
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
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
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.
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
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.