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Flood protection project
Coyote/Berryessa creeks
Project goal:
To provide flood protection for Silicon Valley’s
high-tech, commercial industries and residential areas with potential
damages from a 1 percent flood exceeding $52 million (1993 value) in
an environmentally acceptable way that minimizes
concrete lining and addresses sedimentation.
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Project contact:
For more information about this project, contact:
Marc Klemencic, Manager,
Coyote Watershed, Santa Clara Valley Water
District, at (408) 265-2600, ext. 2084.
Description of the project
Coyote Creek is the first element of the Coyote/Berryessa Flood Protection
Project and drains Santa Clara County’s largest watershed, encompassing
most of the eastern foothills, the city of Milpitas, and portions of
the cities of San Jose and Morgan Hill. For many years, inadequate and
unstable levees constructed by farmers existed along lower Coyote Creek
providing uncertain protection to communities in Alviso, North San Jose,
and Milpitas. Never intended to meet modern flood protection criteria,
the levees were unreliable and posed a great potential hazard to adjacent
development. The Coyote Creek Project, authorized in 1990 was completed
and turned over to the Santa Clara Valley Water District in 1996. The
project extends from San Francisco Bay to Montague Expressway. The project
included levee construction, excavation of a parallel overflow channel,
and extensive environmental mitigation designed in compliance with the
Endangered Species Act.
As a public agency, the district is responsible for designing flood
protection projects which are consistent with environmental regulations
and meet the public concerns. Now underway,
revegetation of 22 acres of riparian forest habitat, which 20 acres
was planted to mitigate for project impacts, is scheduled for completion
in the Spring of 2000. The additional 2.0 acres
was planted at the district’s request for the City of Milpitas
to offset a portion of the impacts from the construction of the Tasman
Drive Bridge Overcrossing. Previously completed,
a 5.2 acre site and a 7.0 acre site of riparian forest habitat was planted
and established downstream of Highway 237 to mitigate for project impacts.
Therefore, a total of 32.2 acres of riparian forest habitat was planted
to mitigate for the flood protection improvements. In addition, the
project included features designed to protect and improve habitat in
an area approximately 52 acres for the state and federally endangered
Salt Marsh Harvest Mouse and to mitigate for loss of salt pond habitat.
The improvements included creation of seasonal
wetlands and construction of a 16.5-acre brackish water bird pond. Environmental
research conducted along the project has led and continues to lead to
improvements in design for flood
protection projects for the district and others.
Berryessa Creek is the second element of the Coyote/Berryessa
Flood Protection Project and as a major tributary of Coyote Creek, Berryessa
Creek drains a large area in the city of
Milpitas and a portion of San Jose. At 320 square miles, the Coyote
Creek Watershed is the largest watershed in Santa Clara County, encompassing
all of Milpitas and portions of San
Jose and Morgan Hill.
In January 1981, the district applied for federal assistance
for flood protection projects under Section 205 of the 1948 Flood Control
Act. The Water Resources Development Act of 1990 authorized construction
on the Berryessa Creek Flood Protection Project as part of a combined
Coyote Creek/Berryessa Creek Project to protect portions of the cities
of Milpitas and San Jose.
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Flooding history
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Berryessa Creek floods on average once every
four years.
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Severe flooding of Coyote Creek occurred in
1982 with 1,700 people evacuated and an estimated 360 homes and
40 businesses sustaining damages in excess of $6 million.
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Storms in January 1997 generated record runoff
in Coyote Creek, but area was well protected by project improvements,
averting estimated damages of $10 to $20 million.
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More severe than 1982, flooding in 1998 caused
no damages to Coyote Creek Project area.
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