Adobe Creek lies within the water district’s Lower Peninsula Watershed and forms the boundary between the City of Los Altos (on the east bank) and the Town of Los Altos Hills (on the west bank). Adobe Creek Upper Reach 5 is located between Foothill Expressway and West Edith Avenue. The extent of the proposed project begins at West Edith Avenue and continues downstream (north) for approximately 1,100 feet.
In May 1999, staff prepared the Adobe Creek Watershed Planning Study, containing an Engineer's Report and Final Environmental Impact Report. As described in the 1999 Planning Study, the Adobe Creek Reach 5 channel improvements consisted of: a wider channel from an approximately 10-foot wide existing channel to an approximate 90-foot top width to convey the 1 percent flow. Gabions would line the City of Los Altos side of the creek to protect mature redwoods. Other modifications included a 10-foot wide low flow channel, a 10-foot wide vegetated mid-bank bench, and a 48-foot to 64-foot-wide high-flow bench. The mid-bank and high-flow benches were vegetated, but limited to groundcover and small shrubs to maintain high-flow functionality. The total length of the multi-level channel improvements proposed is approximately 700 lineal feet downstream of the West Edith Avenue bridge. For an additional 200 feet downstream of the 90-foot wide channel, the existing channel is widened from about a 10-foot width to a 20-foot width, with vertical rock gabions comprising the channel banks.
This design for Adobe Creek Reach 5, completed in 2002, was intended to provide for one-percent flood protection in the creek from the West Edith Avenue bridge to approximately 1,100 feet downstream. Construction of this stretch of creek required a certain acreage of mitigation planting, which the district proposed to install partly along the creek and partly in Edith Park, located just south of the West Edith Avenue bridge.
There was significant community opposition to the proposed creek design and also to the proposed use of Edith Park for mitigation planting. In April 2003, the Los Altos Hills Town Council voted to not grant the district two of the necessary easements to construct the project and install the mitigation planting for Adobe Creek Reach 5.
In September 2003, the water district — in partnership with local municipalities and the Adobe Creek Watershed Group — initiated a collaborative effort to revisit the goals and objectives of providing flood and erosion protection for Reach 5 of Adobe Creek. The collaborative effort included district staff, Adobe Creek Watershed Group members, other creekside residents and citizens, and staff from the City of Los Altos, the Town of Los Altos Hills and various regulatory agencies.
Since September 2003 until the project's completion, the water district held collaborative meetings almost monthly, as well as numerous steering committee meetings (the steering committee is comprised of the primary stakeholders of the Watershed Group) as a means of ongoing public outreach for the project. The meetings provided a forum to identify issues and concerns, develop project objectives, present alternatives and identify the preferred alternative for the project.