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The city of Mountain View is partnering with the Mountain View Whisman School District to fix a treacherous stretch of Stevens Creek, where extensive erosion of the creek bank has threatened to encroach upon both the Stevens Creek Trail and a nearby school campus.
Mountain View Whisman’s board voted unanimously on Thursday, Dec. 18, to commit $990,000 to the project, assisting the city in funding the repairs to the creek bank where it extends onto school district property. In total, the project is expected to cost $3.6 million. The school district had previously earmarked between $600,000 and $800,000 for its share of the repairs, but costs have increased since then.
Erosion along Stevens Creek has been an ongoing, perennial problem in Mountain View. Wet weather and heavy winter storms take a toll on the natural creek channel, causing portions of the bank to slough off into the creek bed. The result is that gradual bank slopes become sheer walls, storm drains are exposed and nearby areas like Stevens Creek Trail are threatened.
The latest trouble spot is between Moffett Boulevard and Middlefield Road, adjacent to Stevens Creek Trail, Whisman Park and the German International School of Silicon Valley, which rents the campus from the Mountain View Whisman School District. A survey by a consultant found four segments of the creek bank have “severely eroded” as a result of wet winters spanning from 2022 to 2024, according to an October 2024 report to the school board.
The most striking damage is just south of the bridge to Whisman Park, where the erosion is creeping up on Stevens Creek Trail, as well as closer to Middlefield Road next to the school, where a chunk of the bank has collapsed and left a concave, sheer drop to the creek bed. Orange, plastic fencing at the location has fallen apart over time.
The city is taking the lead on the project to shore up and repair the creek bank and mitigate future problems, including the design of the repair work, getting the necessary permits, and paying the majority of the costs. Three of the four spots flagged for erosion issues are on city property, and as such, the city will be paying just shy of three-fourths of the costs. The latest estimates are that the city will pay $2.6 million and the school district will pay just under $1 million.
Proposed fixes include re-grading the eroded areas, which will reduce the bank slope and re-introduce vegetation to the bank surface, according to a school district staff report. One re-grading method will involve installing “log crib walls,” a natural retaining structure that uses a mix of tree logs, rocks and compacted soil to reinforce the creek walls for future storms. Exposed and damaged storm drain pipes will also need to be replaced.
Rebecca Westover, Mountain View Whisman’s chief business officer, said the school district opted for a partnership that puts the city in the leadership role, telling trustees last week that these types of projects fall out of the purview of school district operations and maintenance. The city will be handling monitoring reports, inspections, repairs and replanting.
Though the school district and the city agreed to partner up and repair the creek in October last year, it’s been slow going. Projects involving the creek require regulatory approval from three agencies – the San Francisco Bay Regional Water Quality Control Board, the United States Army Corps of Engineers and the California Department of Fish and Wildlife – and require an encroachment permit from the Santa Clara Valley Water District, which has an easement in the creek. Also bogging down the process is that repair work has to be undertaken during the dry season, specifically from June through October.
The city has sent permit applications to the four agencies to get approval for the repair work, and the intent is to start construction in the summer next year
Elsewhere along Stevens Creek, the city has been mapping out additional trouble spots in need of repair. Past issues have been flagged at Sleeper Avenue, specifically under the bridge to Stevens Creek Trail, and at Mockingbird Lane in Sunnyvale.
The most significant damage over the last decade has been along the creek bank north of El Camino Real. In 2017, significant rainfall weakened the soil and caused a landslide that tore off a roughly 180 foot section of the creek bank, creating a 25-foot nearly vertical drop into the creek bed just inches from the trail. The city had to create a temporary trail detour through an adjacent hotel property while work to rebuild the creek embankment took place. Full restoration of the trail took more than a year.
In 2011, the creek bank just south of El Camino Real collapsed, damaging units in the Sahara Mobile Village. The incident roused debate over the lack of preventative measures taken on private property, and whether reinforcing the creek bank is the responsibility of the water district or the mobile home park owner.
Frustrating that so many agencies need to authorize the project. The process alone is delaying the project and increasing the costs. State needs to reduce the bureaucracy.
Time to reintroduce beavers to the upper Stevens Creek watershed to slow storm runoff.
The city of Mountain View needs to put more money into the project.
The school district doesn’t have a lot of spare money like the city does.
The school district is looking at layoffs do to the federal funding cuts.
Think of the children!