M&T/Llano Seco Fish Screen Facility Short-Term / Long-Term Protection Project

Introduction and Background

The M&T/Llano Seco pumping plant location is just downstream of the confluence of Big Chico Creek and the Sacramento River, on the east bank of the Sacramento River just south of the Bidwell State Park at river mile (rm) 193, approximately 6 miles SSW of the City of Chico View Location. The pump diverts water from the Sacramento River to M & T Ranch, Llano Seco Ranch, and the State and Federal Llano Seco Wildlife Refuge. The pumping plant has a capacity of 150 cfs and pumps water year-round. See the Project Timeline below.


Sediment deposition has posed a threat to the normal operation of the fish screened diversion. An encroaching gravel bar adjacent to the Bidwell State Park migrates at an unpredictable rate to the vicinity of the fish screened diversion and WWTP outfall. As a result of this sediment deposition, the intake screens are no longer receiving sufficient sweeping flows, potentially adversely impacting anadromous fish in the Sacramento River and Big Chico Creek. The uncertain rate of river meandering and sediment deposition will continue to pose problems to the operations and safety of the M&T/Llano Seco intake and fish screen system. The rate at which the sediment is accumulating near the fish screened intake is mostly dependant on the flow conditions on the Sacramento River (the gravel bar growth and rate of migration is accelerated during wet years). This condition poses a dilemma between protecting ecosystem functions by accommodating the natural processes of the river and also protecting the present pumping facility in order to provide a fish screened diversion without presenting a threat to the anadromous species and providing water for crops, habitat and waterfowl.

Project Timeline

1915Intake Pumps located in Big Chico Creek, about 0.5 miles upstream from confluence with Sacramento River for providing water to two large ranches.
1980sIntake identified as impacting resident and anadromous juvenile fish, particularly spring-run Chinook salmon. Several state and federal planning documents identify relocating and providing for function of intake.
1991M&T enters management agreement regarding Butte Creek waters and water diverted from Sacramento River. M&T, USFWS, CDFW, TNC enter agreement for fee title and easements.
1995-2001Upstream bank-attached gravel bar migrates downstream towards intake and also City of Chico sewer outfall facilities.
1996-2007West bank of Sacramento River eroded by up to 400 feet upstream from pumps and City of Chico outfall.
1997$5 million M&T/Llano Seco Pumping and Fish Screen Facility (M&T Pumps) moved from Big Chico Creek to east bank of Sacramento River, south of Bidwell State Park.
2001 & 2007200,000 and then 100,000 tons of material dry dredged from gravel bars as short-term solution to limit sedimentation. Information & reports of the six technical workshops produced.
2003-2011Expert panel meets with stakeholders to develop and assess alternatives for a long-term solution
2007Short-term bank protection project initiated. 1,500 feet of short-term toe-protection bank protection installed on west side of river at SRNWR.
2010City of Chico moves wastewater outfall 1200 feet downstream, estimated to provide 15-20 years of project life.
2011Alternatives Assessment Report released: 17 potential alternatives identified.
2013-2014EA/ISMND prepared for additional short-term protection of facility and permitting two additional gravel removals if deemed necessary
2014Ducks Unlimited / CDFW release RFP for Long-term Protection Project.
2015ICF selected as firm to facilitate CEQA/NEPA requirements of long-term alternatives. Stake holder group assembled. Public meetings of NOI/NOP planned for late spring.

Documents and Links