Spotlight on Hamilton City levee project

The U.S. Army Corps of Engineers, Sacramento District recently reached two important milestones for the small town of Hamilton City, California, located about 100 miles north of Sacramento.

Home to just under 2,000 people, the history of Hamilton City includes many flooding events and several near misses.

One of the primary reasons for this susceptibility to flooding has been the town’s reliance on a substandard and undersized levee called the “J levee” – a levee that does not meet any USACE engineering standards.

Margaret Engesser, a project manager with Sacramento District, has become very familiar with the Hamilton City and its levee system.

“December was an important month for the Hamilton City Flood Risk Reduction and Ecosystem Restoration project,” said Engesser. “It marked the completion of the construction of a portion of the new Phase 2B levee that will add additional protection for the town. Additionally, the first phase of the ecosystem restoration was completed.”

On December 17, Engesser joined Reclamation District 2140, California State Parks, and Larsen Wurzel & Associates to conduct a final levee inspection of just over a half-mile of the recently completed levee. The levee inspection was the final walk-through to ensure the work has been completed to the Corps’ required specifications.

The Hamilton City Project is unique because it is one of the Corps’ first multipurpose projects, authorized for the purposes of flood risk management and ecosystem restoration. When completed, it will include 6.8 miles of new “setback” levee, providing much-needed flood protection, and will restore approximately 1,500 acres of native riparian habitat.

Construction work on the project over the past year has included degrading the existing J levee, filling the gaps in the existing Phase 2A levee that was constructed in 2018, and placement of rip rap (heavy rocks) to protect the riverbank and the Highway 32 Bridge. By degrading the J levee, the new setback levee widens the channel and allows the river to reconnect to the natural floodplain.

Engesser said that the completion of this new portion of the Phase 2B levee and the first phase of ecosystem restoration is a big accomplishment but added that there is still much more work to be done.

Over the next 1-2 years, a section of the Phase 2B levee still needs to be constructed. Once that has been completed, Hamilton City will be protected by an entirely new levee system that will provide much-improved flood risk management for its residents.

On top of these recent milestones, the Hamilton City Project was recently approved for $22 million in federal funding to complete the project and ensure that the full levee will be completed with all ecosystem restoration features established.

Written By J. Paul Bruton/U.S. Army Corps of Engineers Sacramento District