By Sarah Haselton
On a Tuesday morning at the Wildcat Creek Fish Ladder, I had the opportunity to help conduct a sediment survey and learn about the importance and functions of fish ladders. The Watershed Project has been involved with this particular fish ladder in the past, along with several other organizations such as Trout Unlimited, Contra Costa County Flood Control, Contra Costa Conservation District, the California Department of Fish and Wildlife and the Cities of San Pablo and Richmond. These organizations all worked together to hold an event for Coastal Cleanup day in 2018. The event focused on removing accumulated sediment in the fish ladder as well as a general cleanup of trash around the site itself.
The functional purpose of fish ladders is to allow migrating fish a passage way along the flood control channel. Anadromous steelhead migrate up creeks and streams from the ocean to spawn, and then return to the ocean. The wildcat creek fish ladder was built in the mid 90’s by the US Army Corps of Engineers and is meant to assist steelhead trout on their migrations. There are several fish ladders within the Bay Area, with various designs selected to provide for migration. Building fish passages and ladders is a complex process as countless factors must be considered such as fish species’ swimming ability and overall fish behavior and local channel and watershed characteristics.
I was fortunate to both work at the Wildcat Creek fish ladder as well as speak with Peter Mangarella a little bit about his work with Trout Unlimited. This shed light on some of the core issues that the fish ladder has experienced. Two weeks prior to the maintenance and monitoring I conducted alongside Peter there was a storm which significantly raised the flow rate in the creek which transported large amounts of gravel and sediment into the fish ladder. This particular storm event at the beginning of February 2019 rendered the fish passage inoperable. There was a large amount of tree branches and human products such as mattresses, clothing and a bike that accumulated in the passageway of the fish ladder contributing to the clogged pathways. The three main contributing factors to the inoperability of this particular fish ladder are the outdated design and structural components, the human products building up in the creek itself, and lastly, the natural watershed itself generates large amounts of sediment.
Moving forward it would be beneficial to continue working at this particular fish ladder to better understand the functionality of the site. It is also vital that the human created waste build up is acknowledged and dealt with properly to avoid further clogging of the passage for future fish migrations. I encourage you to engage with citizen science programs and learn more about your local fish ladders. You can see the fish ladder and get involved in helping keep Wildcat Creek clean on Earth Day, April 20. Check out our events page for details and to register.
