Hale Creek Pilot Enhancement Project

In response to repeated and large-scale floods through the 1950s, the Santa Clara Valley Water District (District) constructed many miles of flood protection projects, including concrete-lined channels. While these channels have generally achieved their main goal of reducing flood risk and damage, many of the concrete-lined channels that the District constructed are now well over 50 years old and are reaching the end of their originally planned life cycle. Many resource agencies now avoid using hardscape flood protection solutions, and newer methods and alternative solutions exist. Rather than simply replacing these channels, this project took a natural approach to flood protection. These methods included flood retention, stream restoration, and multi-stage earth-lined, vegetated channels. If successful, this pilot project will serve as a model for restoring other concrete channels in the South Bay that are facing similar issues.

We will remove the existing concrete channel bank and invert lining and replace it with a vegetated earth channel with hardened outside retaining walls. Our team will widen the flood-prone area available to the stream, restore the natural channel bank and invert lining, allow natural stream recharge, reduce the channel slope, restore channel meander, allow meander development into the future, and lower the one-percent and lower flood event water surface elevations.

Overall, the scope of the project consists of removing approximately 650 feet of existing concrete trapezoidal channel lining on Hale Creek from upstream of Marilyn Drive, City of Mountain View, to downstream of North Sunshine Drive, City of Los Altos. We will also remove chain link and wood fences within temporary construction easements (TCEs), trees, shrubs, storm drain outfalls, Marilyn Drive access ramp, concrete curbs, asphalt concrete pavement and subgrade, a gas line, and a 30x15-foot bridge. Our team will install a new 30x12-foot prefabricated steel bridge to span between the east and west banks slightly downstream of the previous bridge.