Castro Valley Creek Restoration

A stretch of Castro Valley Creek, next to the new Castro Valley Library, was once buried underground in a culvert and covered with an asphalt parking lot. In a major 2007 restoration project, the District demolished a 300-foot-long by 12-foot-wide by 6-foot-high concrete box culvert and brought the creek back into the daylight.

To increase the creek’s capacity to carry a 100-year flood level, creek banks were widened, reconstructed, and bioengineered. The channel was configured with a “step-pool system,” using riffles (an area where purposefully installed boulders create choppy water), runs, and deep pools. These pools provide a variety of habitats that have become home to many different organisms. Rootwads (tree trunks with roots attached) were added, and native plant species were planted along the channel’s inside banks to create a more natural riparian habitat.

A creekside amphitheater was also installed and can be used by teachers as an outdoor classroom to help students to learn about creek ecosystems.

In a collaborative agreement with the city of Union City, the District received $500,000 in funding for the Castro Valley Creek restoration project in return for converting 700 feet of open channel, owned by the District in Union City, into an underground culvert. The underground channel conversion was part of constructing the new transit hub at the Union City BART station.

The second phase of the project, completed in fall 2010, added a trail along the restored section of Castro Valley Creek. The area was enhanced with rustic fencing, benches, and trash receptacles designed by two Bay Area artists. Invasive nonnative plants were removed and replaced with native species. Two rain gardens and a bioswale were also added. A pedestrian bridge—made from a recycled and converted railroad flatcar—was installed in summer 2009 to link the trail with the library. Interpretive signs were installed to explain the creek habitat and importance of flood control.

The Hayward Area Recreation and Park District built a playground located across the stream from the children’s wing of the library. The tot lot includes rock-climbing structures, boulders for seating and climbing, ropes, and concrete animals—a turtle and a frog—that kids can play on.

Trail lighting and more interpretive signs, which will link to the ecology section of the library, will be added at a later date. All of these efforts are intended to increase public awareness about the practice of stream restoration while providing recreational amenities.