River Partners Will Assist in Historic Flood Management Project at Hamilton City

By Mike Cook, Sacramento Valley Regional Director

Looking north towards the community of Hamilton City, the Sacramento River flows past the project site and CDFW’s Pine Creek Unit (in foreground). During this initial phase of the project, a new setback levee will be constructed to provide greater flood protection for the community and the existing “J Levee” (where the gravel road can be seen in photo) will be removed to reconnect over 500 acres of floodplain to the river. Once completed, River Partners will restore approximately 770 acres of former ag land to high-quality riparian habitat. (Photo by Stephen Chollet)

Many riverside communities in the Central Valley are no stranger to living with flood risk, but for one small town in Glenn County, a new paradigm has evolved. With significant leadership from the local Reclamation District 2140, the US Army Corps of Engineers and California’s Department of Water Resources, the Hamilton City Flood Damage Reduction and Ecosystem Restoration Project has broken ground as a model multi-benefit river restoration project. And River Partners is excited to be a part of it!

Hamilton City (population 1,700, about 10 miles west of Chico) has been at high risk of flooding for a very long time. Residents have been evacuated six times due to flooding in the last 20 years: 1983, 1986, 1995 (twice), 1997, and 1998. The existing levee, commonly referred to as the “J Levee”, was constructed in the early 1900s and provides some flood protection for frequent events. However, this levee is prone to failure and expensive to maintain as it wasn’t engineered to current standards.

The new project will construct a 6.8-mile setback levee that will reconnect 1,480 acres of floodplain to the Sacramento River. The lands which had been farmed will be restored to wildlife habitat. Both the levee construction and the habitat restoration will be completed in phases and is estimated to cost $65 million which will be shared amongst federal and state sources.

The plan includes restoration of riparian forest, scrub, oak savanna, and grassland habitat types. The reconnection of floodplain with the river will support the recovery of endangered salmon as well as other birds and mammals.

Construction of the setback levee and removal of the J Levee began earlier this year. River Partners was recently awarded the contract to install the first phase of the ecosystem restoration portion of the project over the next 3½ years. Being no stranger to large-scale habitat restoration and located so close to the project site, our team was a natural fit for the job. Many of our partners have also been very supportive of us winning the contract, including The Nature Conservancy and Reclamation District (RD) 2140. “I am overjoyed that River Partners received the Restoration Award for the Hamilton City Flood Damage Reduction and Ecosystem Restoration Project! River Partner has been a long standing partner and neighbor for a majority of the time it has taken us to get to this point in the project. RD 2140 is excited for our future to complete the project together,” said Lee Ann Grigsby-Puente, President of RD 2140.

If we have been doing projects like this for so long, how can we call this one a new paradigm? It comes down to the way the local community has partnered with environmental interests to make its case for funding. According to federal expenditure requirements, the US Army Corps of Engineers must consider the cost versus the benefit of any federal expenditure in flood management. Construction of large engineered levees is very expensive. The assets being protected by them often need to be very high value to justify the cost. A small community like Hamilton City is already at a disadvantage in the cost-benefit equation merely because of its size. By including the value of the restored ecosystem as part of the “benefits” side of the equation, this project was able to not only meet the federal requirement, but blow it away with a benefit-to-cost ratio of 1.8. If we can successfully place a reasonable value on ecosystem recovery that can be used rationally as is the case in Hamilton City, we’d see considerable movement of the needle on the gauge of ecosystem recovery in the Central Valley.

The above article originally appeared in the Fall 2016 issue of the River Partners Journal.