By Ana Weidenfeld
Over the past one hundred years, migratory fish have lost 90% of their access to spawning grounds in the Central Valley, leading to a steep decline in population numbers. A telling example is the story of the Central Valley Chinook salmon, which used to swim from the Pacific Ocean to Marsh Creek, one of the first major tributaries along the way up the San Joaquin River, to lay their eggs.
Marsh Creek is the second largest watershed in Contra Costa County, originating on the eastern side of Mount Diablo and collecting water from a handful of streams before reaching the western delta at Big Break. Scientists have documented spawning salmon in Marsh Creek for over 100 years. Fish access to upper Marsh Creek, however, was eliminated in 1958 by the construction of a six-foot tall waterfall by the Natural Resource Conservation Service and the Contra Costa Flood Control and Water Conservation District. This waterfall, or “drop structure” as it’s called by stormwater professionals, was built four miles upstream from the mouth of Marsh Creek. Its purpose was to slow the creek’s flow and reduce flooding.
The drop structure has drawn considerable attention from community members, especially those of the nonprofit organization Friends of Marsh Creek Watershed, who spotted dead Chinook salmon floating at the base of the structure. By monitoring the site, the group determined that the drop structure was acting as a physical barrier to passage by migrating fish.
Additionally, five years after the installation of the drop structure, Contra Costa County built the Marsh Creek Reservoir three miles upstream from Brentwood. This affected non-migrating fish like Sacramento Suckers, catfish and Blackfish because they were trapped between the drop structure and the dam.
Efforts to aid these fish populations began in 2000 with monitoring of fish killed because of the drop structure. The Friends of Marsh Creek Watershed took the lead on this project and fundraised thousands of dollars to build a fish ladder up the drop structure. The Friends partnered with Contra Costa County to get the proper permits and ensure long term maintenance of the ladder as well as additional financial support.
After many years of project planning, last year, GSE Construction of Livermore started work on the ladder. The project was completed in December 2010, prompting joyous celebration from the creek- and fish-loving community. “It wasn’t easy or a quick fix to get this fish ladder built, says Diane, executive director of Friends of Marsh Creek Watershed, “But the passion that our community felt about doing the right thing for the fish kept us going.”
This fish ladder acts as a channel that sidesteps the drop structure. It begins downstream of the drop structure and allows fish to jump through a series of pools alongside the structure, reconnecting with the creek at the top. It allows the salmon to travel seven more scenic miles up Marsh Creek, Deer Creek and Sand Creek to spawn, until they hit the dam. These seven miles are important for salmon populations because the gravel and vegetative cover found in this area is deemed very conducive for spawning in the fall and winter months.
This tremendous project shows the importance of community activism and also demonstrates that endeavors for a better environment are well worth the effort because results can be achieved.
