Priority E: Provide Flood Protection to Homes, Businesses, Schools and Highways


Valley Water’s mission includes providing flood protection to the people and businesses of Santa Clara County through construction projects.

Our efforts are prioritized to protect the largest number of people, homes and businesses, as well as safeguard the highways, streets, public transportation and business centers that people depend on for their livelihoods.

Valley Water partners with the federal government on the construction projects under this priority, and all these projects will require federal and state funding in addition to local funding.



Permanente Creek Flood Protection Project:

Flood protection can take on a number of different forms. In Mountain View, Valley Water’s flood protection project at McKelvey Park has taken the form of a recreational facility.

The sunken baseball fields at McKelvey Park will contain floodwaters when Permanente Creek overflows and are part of the Permanente Creek Flood Protection Project.

The creek has a history of flooding, which can result in millions of dollars in damage to homes, businesses and schools. The full Permanente Creek project, scheduled to be completed in 2020, will provide flood protection to about 2,200 properties in Mountain View and Los Altos, create recreational opportunities and enhance the environment. The project, which spans 10.6 miles of Permanente Creek, from San Francisco Bay’s southwest shoreline through Mountain View to Foothill Expressway in Los Altos, includes multiple elements.

The project includes multiple elements: channel improvements; flood detention area and recreational improvements at City of Mountain View’s McKelvey Park; and flood detention areas, recreational improvements and enhanced habitat at County of Santa Clara’s Rancho San Antonio Park.


San Francisquito Creek Flood Protection Project Phase 1

With the completion of a portion of this project from San Francisco Bay to U.S. 101, about 3,000 parcels have been protected from a flood on San Francisquito Creek like the one that struck in 1998 and left hundreds of people evacuated from their homes.

The improvements included a widened creek channel into the Palo Alto golf course, improved access to trails and existing marsh habitat, and a beautiful boardwalk extension to the popular Friendship Bridge. An ecotone, which slopes more gradually than a typical levee, creates a more natural, gradual transition from the levee to the adjacent marsh, and as the sea level rises, the levee will adapt and continue to provide flood protection.

Design work is continuing on Phase 2 (upstream of U.S. 101) of the three-phase project.

This is just one of the creative ways that Valley Water has worked with the community to provide flood protection while enhancing the environment.


Upper Llagas Creek Flood Protection Project

This project consists of nearly 14 miles of flood protection improvements along East Little Llagas, West Little Llagas, and Llagas creeks within the cities of Gilroy, Morgan Hill, and the unincorporated area of San Martin.

In September 2019, Valley Water began construction on the locally funded Reaches 4, 7a, a portion of Reach 5 and Lake Silveira, which is expected to be completed in 2022. Construction of the approximately 2,300 linear feet of a horseshoe-shaped underground tunnel and approximately 1,600 linear feet of twin reinforced concrete box culverts upstream and downstream of the tunnel to carry high water flows is scheduled to begin in November 2020. Construction is expected to take 2.5 years. Valley Water has also removed invasive plants, concrete rubble and trash, while also excavating to restore part of the creek.

More work needs to be done, including the construction of improvements on approximately 8 (eight) miles of Upper Llagas Creek, from US 101 to Llagas Road, to provide an increased level of flood protection. Construction will include creek widening and deepening, bridge/culvert construction, utility coordination and relocation, construction of maintenance roads, and channel stabilization with habitat enhancements.


Coyote Creek Flood Protection Project

Valley Water is committed to finding practical solutions that allow us to move quickly to protect communities along Coyote Creek that are subject to flooding. While typical flood risk reduction projects require lengthy review and permitting timelines from state and federal regulatory agencies, Valley Water is looking at set-back floodwalls and berms, floodproofing, and other low-impact work to avoid channel impacts while also reducing permitting delays.

Valley Water has already completed a series of short-term efforts to reduce flood risk and improve ecological habitat, including building a temporary floodwall to provide flood protection for the Rock Springs, Nordale, and Bevin Brook neighborhoods; removing invasive and non-native vegetation to improve Coyote Creek’s ecological habitat quality; extending the project area to include communities from Montague Expressway to Tully Road; repairing a 150-foot section of a levee located behind the South Bay Mobile Home Park community; installing flood gauges on bridges that provide real-time visual information on water levels; and enhancing emergency communications and looking for partnership opportunities with local cities.

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