Sutter Extension Water District outlines Sunset Weir removal and new pump station to restore fish passage

Sutter Extension Water District on Thursday presented a detailed plan to remove the Sunset weir, build a replacement pump station with modern fish screens and stabilize a failing section of the river’s left bank to restore fish passage upstream.

Lynn Phillips, general manager of Sutter Extension Water District, told the Sutterbutes Flood Control Agency board that the district relies on the Sunset pumps to make up canal capacity shortfalls and that the existing 10‑foot boulder weir, installed in the 1920s, can impede fish passage at low and moderate flows. Rachel Balante, a Department of Water Resources project manager, said the proposal has two co‑equal goals: “to accommodate the passage of threatened migratory fish species at the Sunset weir,” and to “preserve overall water‑delivery system stability and reliability with no change in SEWD’s operations.”

Consultant Jonathan Kors detailed the package of work: removing the weir, constructing a reinforced‑concrete pump intake and sump with five conical fish screens feeding six pumps sized to match existing diversion capacity, and stabilizing an ongoing left‑bank erosion by laying back slopes, placing rock slope protection and planting willows. The team said removal of the weir would restore unimpeded passage to roughly 28 miles of river upstream of the structure.

Designers said most permanent facilities will sit outside the levee; the only in‑levee work would be replacement discharge piping that crosses the levee into the Sutterview main canal. Kors said the project team will request a local levee‑district endorsement (Levy District 9) as part of the Army Corps 408 permit process and that contractor access during construction will require temporary ramps and a crane pad.

The consultants emphasized sequencing and environmental constraints. Kors told directors that the weir cannot be removed until the replacement intake and pumps are in place because the existing station would not function at the lower water surface after removal. He also described two temporary bypass options for keeping water service during construction: tying temporary pipes into an existing manifold (which would avoid levee disturbance) or routing pipes up and over the levee on a temporary ramp (fill over pipes). On the levy impact question, the team said the presented ramp option would use fill over pipes and would not require excavation into the levee.

Permitting, environmental work and construction windows are driving the schedule: staff said the project is approaching 95% design, with one more round of geotechnical borings required in the July 15–September 30 in‑water window; the team is pursuing a Section 408 approval from the Army Corps and other clearances before bidding. The team’s present schedule shows construction targeted for 2027, but staff said securing the 408 permit and right‑of‑way access are critical prerequisites for bidding in late 2026 and beginning construction when the floodway work window opens in April.

The agency’s board asked several technical questions about sequence, temporary bypass impacts and environmental constraints; the presenters said they are coordinating with the Department of Fish and Wildlife and federal agencies and that they are aiming to minimize off‑site export of excavated material by re‑using cut material on site.

The presentation concluded with a reminder that the in‑water work window for fish‑sensitive species and other constraints (July 15–Sept. 30) will tightly constrain construction steps and that additional permits and approvals must be in hand before major work begins.