Lower Butte Creek
Several agencies and water districts have implemented restoration projects in the Butte Creek watershed, with the goals of improving fish passage, increasing natural salmon and steelhead production, and enhancing riparian habitat. Lower Butte Creek encompasses Butte Sink south through the Sutter Bypass.
We coordinated permitting for the Sutter Bypass East Borrow Canal Water Control Structures Project, which consisted of modifications to Weir No.2 and Willow Slough Weir.
Weir No. 2
Weir No. 2 is located along the East Borrow Canal (EBC) of the Sutter Bypass, in Sutter County, and is owned and operated by DWR. The original structure consisted of concrete piers which created twelve bays containing wooden flashboards used to control the upstream water elevation, and a pool and weir fish ladder with a capacity of 13 cubic feet per second (cfs), located at the right abutment.
The new Weir No. 2, which has the same dimensions as the existing weir, was constructed downstream of the existing weir. The new fish ladder was constructed on the bank opposite the existing fish ladder. The new weir has 3 main channels, which use remotely operated inflatable Obermeyer gates to control water levels upstream in the EBC, and 6 side bays controlled by manually removable flashboards. The new fish ladder is a full Ice Harbor design which will facilitate passage of adult and juvenile salmon and steelhead past the structure over a greater range of flows. This design was chosen after an analysis of conditions and needs at the site by DWR, California Department of Fish and Wildlife (CDFW), and National Marine Fisheries Service (NMFS) staff and after receiving input from other agencies and stakeholders.
We prepared a preliminary engineering technical report (18 MB) in 2003 and a mitigated negative declaration and initial study for the project, as well as, obtained all local, state, and federal approvals and permits for the project.
Willow Slough Weir
Willow Slough Weir is an earthen dam constructed in the 1920s to control water levels in the EBC for agricultural diversions. The original structure had 2 60-inch diameter corrugated metal pipe culverts and a 60-inch diameter concrete culvert that conveyed flow, controlled by slide gates from the lower end of the EBC into Willow Slough; and a Denil fish ladder that was constructed in the 1980s to provide anadromous fish passage.
The project included the removal of the existing fish ladder and culverts and the replacement of the original culverts with new structures whose design and configuration provide better flow control from the EBC into Willow Slough, and provide effective fish passage between the two waterways. Four new corrugated metal pipe culverts were installed to provide more flow capacity, and a new pool and chute fish ladder, which operates in a greater range of flows (6 to 270 cfs), was constructed through the weir. The fish ladder design was the alternative chosen after an analysis of conditions and needs at the site by DWR, CDFW, and NMFS staff, and after receiving input from other agencies and stakeholders.
We completed a preliminary engineering technical report (7.5 MB), funded by the U.S. Fish and Wildlife Service (USFWS) Anadromous Fish Restoration Program, in 2005. We prepared a mitigated negative declaration and initial study for the project, as well as, obtained all local, state, and federal approvals and permits for the project.
Is this an Active Project or Completed Project? Completed.
Watershed: Lower Butte Creek / Sutter Bypass
Why is the project needed? What are the project goals?
The original Weir No. 2 structure was in place for more than 50 years. Wear and deterioration has taken a toll on the structure to the point that maintaining a normal upstream operating stage for diversions and a fish ladder wasn’t possible during certain low-flow periods. Replacement of Weir No. 2 was necessary due to the deterioration and the excessive leakage of the structure. The existing weir was also an operational hazard because it relied on flashboards that are manually placed and removed from a narrow walkway, which exposed personnel to possible injury with every flow adjustment.
The original Willow Slough Weir fish ladder, which had a capacity of 90 cfs, had a number of structural issues and failed to provide the appropriate attraction flow when compared to the water being discharged through the culverts during much of the migration season. In addition, the existing culverts were undersized with respect to the planned operational flows from the EBC into Willow Slough.
The objectives of the project included:
- Replacing the existing manually operated Weir No. 2 flashboard structure with a remotely operated gate structure that is safer and more effective to operate
- Reconstructing the earthern Willow Slough Weir and replace its culverts to improve flow of water from the East Borrow Canal into Willow Slough
- Replacing the fish ladders at both weirs to improve passage for migrating Chinook salmon and steelhead
Long Term Maintenance
On June 16, 2008, we submitted a Proposed Mitigated Negative Declaration and Initial Study (MND/IS), pursuant to the California Environmental Quality Act (CEQA), for the Sutter Bypass East Borrow Canal Water Control Structures Project to the State Clearinghouse. After the public review period ended, we revised the MND/IS and added Appendix N, which includes comments pertaining to the proposed MND/IS and our responses to the comments. DWR certified the MND/IS and submitted a Notice of Determination (NOD) to the State CEQA Clearinghouse.
In 2009, we recirculated the Proposed Mitigated Negative Declaration (MND/IS) for a 30-day public review period to disclose additional impacts and mitigation resulting from project changes. The comment period ended October 12, 2009 and the Notice of Determination (NOD) (64 KB) was submitted to the Clearinghouse on October 19, 2009.
In addition to CEQA compliance, we obtained all local, state, and federal approvals and permits prior to the start of construction for both Weir No. 2 and Willow Slough Weir.
Replacement of the culverts and fish ladder at Willow Slough Weir was completed in 2010 and construction on Weir No. 2 was completed in 2013.
Sutter Bypass restoration activities were coordinated through the Lower Butte Creek Project's Sutter Bypass Eastside Stakeholder Group. Members of the stakeholder group included us, California Department of Fish and Wildlife (CDFW), National Marine Fisheries Service (NMFS), Ducks Unlimited, Sutter Bypass Water Users Association, Butte Slough Irrigation Company, U.S. Fish and Wildlife Service (USFWS), and the U.S. Bureau of Reclamation.