Palo Alto Tide Gate Project Reaches Key Milestone

May 5, 2026

The tide gate structure has been seismically retrofitted and rehabilitated, featuring deeper foundations to withstand extreme seismic events, new barrier fencing, and a newly resurfaced top.

Valley Water has reached a major milestone in extending the life of an important flood protection system in Palo Alto. In February 2026, the agency completed Phase 1 of the Palo Alto Flood Basin Tide Gate Structure Seismic Retrofit and Rehabilitation Project.

The Palo Alto Flood Basin tide gates have protected communities along the San Francisco Bay shoreline for nearly 70 years. Built in 1957, the structure plays a critical role in managing water levels and preventing flooding in low-lying areas near Matadero, Adobe, and Barron creeks. After decades of service, however, the structure is showing signs of wear and needs repairs.

The tide gates are located where the Palo Alto Flood Basin meets the San Francisco Bay, about half a mile northeast of the Byxbee Park parking lot along the Adobe Creek Loop Trail. The tide gates control the flow of water between the creeks and the bay. They act like a valve, keeping bay water out during high tide and allowing creek water to drain out when tides recede. The surrounding levee encloses a 600-acre basin that temporarily holds stormwater, helping protect nearby homes, businesses, schools, and a portion of Highway 101 during heavy rains.

But constant exposure to saltwater and harsh Bay conditions has caused deterioration, including cracked concrete and exposed steel. The facility also no longer meets current seismic standards, increasing its vulnerability during a major earthquake.

To fix these issues, the multi-phase project will extend the tide gate’s service life by at least 20 years while plans for a full replacement move forward.

Phase 1, completed in February 2026, aimed to strengthen the structure and improve safety and access. Workers installed deep-pile foundations to make the area more stable during earthquakes. They repaired damaged concrete and added a protective layer to the tide gate deck. The project also included a new barrier fence for pedestrian and bicyclist safety, improved maintenance access, and the restoration of nearby areas through hydroseeding and native plantings.

With Phase 1 complete, the tide gates are better equipped to continue providing reliable flood protection in the near term. Phase 2 is now underway and includes a three-year plant establishment period required under environmental permits. This phase will continue through early 2029 and supports habitat restoration in the surrounding Baylands.

Phase 3 is scheduled for fall 2026 and will replace six aging hydraulic flap gates identified during routine inspections.

While these upgrades address immediate needs, Valley Water is also planning for the future. In partnership with the U.S. Army Corps of Engineers, the agency is working toward a long-term replacement of the tide gate as part of the South San Francisco Bay Shoreline Phase II Project. The future structure will be designed to meet modern engineering standards while aligning with broader regional flood protection efforts.

Valley Water’s continued investment in the Palo Alto tide gates reflects its commitment to protecting people, property, and the environment. As sea levels rise and storms become more intense, maintaining and modernizing this infrastructure is essential to keeping communities safe along the Bay.

The update also included a modified trash rack that features maintenance access and ladder rungs for easier access.

Workers repaired damaged reinforced concrete and resurfaced the structure's top with polyester polymer concrete.

A view of the tide gate structure before construction.

Valley Water manages an integrated water resources system that includes the supply of clean, safe water, flood protection and stewardship of streams on behalf of Santa Clara County's 2 million residents. Valley Water effectively manages 10 dams and surface water reservoirs, three water treatment plants, an advanced recycled water purification center, a state-of-the-art water quality laboratory, nearly 285 acres of groundwater recharge ponds and 333 miles of waterways. We provide wholesale water and groundwater management services to local municipalities and private water retailers who deliver drinking water directly to homes and businesses in Santa Clara County.