The U.S. Army Corps of Engineers Sacramento District awarded an $8.6 million contract on September 14 to River Partners of Chico, CA, to begin the first phase of revegetation for the Hamilton City Flood Damage Reduction and Ecosystem Restoration project. River Partners is a nonprofit company that implements large scale restoration projects along streams and rivers across the Western United States, including the Colorado, Sacramento, San Joaquin, Merced, Otay, Tuolumne, Feather and Stanislaus rivers.
The revegetation project, which will install native plantings that can be naturally sustained within the floodplain, is expected to begin later this year. The first phase of revegetation covers roughly 770 acres on the southern end of the project.
Divided into four work phases, two phases each of levee construction and revegetation, the Corps and Reclamation District 2140 are partnering to improve flood risk management for local residents by reducing erosion and maintenance needs by allowing overbank flooding when necessary, and reconnecting native habitats and natural floodplains.
The first phase of levee construction is underway, building about half of a new setback levee that will tie into the existing "J" levee on the southern side of Dunning Slough. The second half of work will begin construction two miles north of Hamilton City and end at its interface with the Phase 1 levee at Dunning Slough.
The overall $67.9 million project will construct a new 6.8-mile setback levee. It is designed to reduce flood risk for Hamilton City and also reconnect and restore nearly 1,500 acres of natural habitat once separated by the existing levee.
Officials say the project is the first in the nation to be authorized for construction under the Corps' guidelines to develop multipurpose projects that include both flood risk reduction and ecosystem restoration features.
Hamilton City is along the west bank of the Sacramento River in Glenn County, CA, about 85 miles north of Sacramento. The community has long been at risk of flooding from the Sacramento River. Portions of Hamilton City and the surrounding area flooded in 1974. Residents of the town were evacuated six times in the past 20 years, including 1983, 1986, twice in 1995, 1997, and 1998.
The city relies on the existing 'J' levee to contain flows in the Sacramento River. The 'J' levee, originally constructed in 1904, does not meet Corps or any other levee construction standards and could fail at river levels well below the top of the levee, says the Corps.
The U.S. Army Corps of Engineers and The Reclamation Board of the State of California completed a feasibility study in 2004 to develop plans to reduce flood damages and restore the ecosystem along the Sacramento River near Hamilton City.
The Hamilton City Levee Construction and Revegetation Project is a dual-purpose flood risk management and ecosystem restoration project, which will construct approximately 7 miles of levee for improved flood protection and about 1,500 acres of native habitat. The new setback levee will provide improved levels of flood risk management and levee stability. Project officials say the restoration work will benefit the recovery and stability of numerous federal and state-listed species, and provide a more natural river function, contributing significantly to aquatic ecosystem restoration along this reach of the Sacramento River.