Lower Sutter Bypass Anadromous Fish Habitat Management Planning Project
Photo by Daniel Nylen
Lower Sutter Bypass encompasses over 6,000 acres of floodplain at the confluence of Butte Creek and the Feather River, immediately upstream of their confluence with the Sacramento River. This location within the designated flood bypass has been described as the single best opportunity for improving floodplain rearing habitat for the salmon populations of the Butte Creek and Feather River watersheds. Current land-use in addition to flood protection includes, agriculture, wildlife refuges and waterfowl hunting clubs, and for multiple purposes including flood safety, food production and wildlife habitat. The Lower Sutter Bypass Anadromous Fish Habitat Restoration Planning Project aims to integrate improved management for fish habitat into this multi-benefit landscape, through a facilitated multi-stakeholder planning process.
Project Location
The Lower Sutter Bypass (from the Nelson Slough Unit to Sacramento Slough) runs for 8.25 miles between the Feather River and lower Butte Creek. The west levee of Butte Creek and the east Levee of the Feather River are flood system levees, but the berms that separate Butte Creek and the Feather River from the floodplains in the bypass are locally owned and maintained. During large flood events the Feather River consistently overtops or breaches these berms. Flood flows spill from the Sacramento River into the Sutter Bypass to the north of the project site via three engineered weirs (Tisdale, Colusa, and Moulton).
How It Could Work
Under the current hydrologic operation of the Bypass, flood frequency and fish access to the floodplain are limited to relatively infrequent large flood events. The floodplains within the proposed project boundary are farmed, primarily to rice. This planning project looks at opportunities to increase the frequency and extend the duration of inundation so that tens of millions of fish could access to high-quality floodplain rearing habitats multiple times every year under multiple and various hydrologic conditions. As high flows on Lower Sutter Floodplain recede and drain back to the stream channels, floodplain-produced food webs (fish food) will also flow downstream, enriching the in-river food web of the lower Sacramento River watershed.
The Challenge
Central Valley salmon populations are dwindling. Managing endangered species is complicated with many levels of regulatory authorities. Accessible inundated floodplains are critical habitat for juvenile salmon. Currently, Lower Sutter Bypass safely conveys high flows floods away from farms and towns during flood; it is productive farmland, and it is a stunningly beautiful landscape that provides important fish and wildlife habitat. All stakeholders in the Bypass including wildlife managers and fish regulators, farmers, water and reclamation district managers Department of Water Resources (DWR) flood managers, and neighbors all have important perspectives and parts to play as we improve this multi-benefit landscape to better provide for fish on the Lower Sutter Bypass.
This challenge –multiple benefit floodplain land use – applies to many parts of the western US where streams have been disconnected from their floodplains. The hope is that Lower Sutter Bypass Habitat Management Plan can be a model for an inclusive, collaborative planning model that empowers participation from diverse stakeholders to scale up solutions for endangered fish population recovery.
Contact Us
Contact Helen Swagerty at hswagerty@riverpartners.org for more info and to receive alerts of meetings and web updates.