The project by the U.S. Environmental Protection Agency, the National Marine Fisheries Service, California State Coastal Conservancy and San Mateo County removed the concrete wall from San Francisquito Creek that was blocking most of the migrating native trout, EPA spokesman David Yogi said.
The barrier was placed in the creek in 1908 to protect the nearby historic El Palo redwood tree from flooding but prevented many juvenile steelhead from swimming upstream to spawn, said Brian Wardman, an engineer from West Sacramento-based Northwest Hydraulic Consultants who worked on the project.
The fish make the upstream swim from the bay each November, when water levels in the free-flowing creek are high due to seasonal rainfall, Mr. Wardman said.
The project removed the last obstacle for migrating steelhead in the San Francisquito, identified as a critical habitat for the fish. The creek serves as the boundary between the cities of Palo Alto and Menlo Park and the counties of Santa Clara and San Mateo.
Jared Blumenfeld, the EPA's Pacific Southwest regional administrator, said with the barrier gone, the steelhead, already a federally threatened species, will be free to move 40 miles upstream from the bay to spawning and rearing grounds.
The unimpeded access to the creek, flowing east toward the bay from Searsville Dam in Portola Valley near Woodside, will improve prospects for the fish species, which have not been doing particularly well in the bay, Mr. Blumenfeld said.
The project to extract the wall, called a "Bonde Weir," from the creek came about after the partnering government agencies together obtained $309,000, including a $75,000 grant from the EPA.