By Don A. Wright
Most of us get along without too much notice of a 27-mile or so long canal. The Folsom South Canal (FSC) starts on the American River east of Sacramento where the Nimbus Dam forms Lake Natoma along Highway 50. It flows west along the highway turning south near Sunrise Boulevard east of Sacramento and continuing south until it ends a few miles east of Galt.
According to the US Bureau of Reclamation website the Folsom South Canal is part of the federal Central Valley Project. It was designed to be 69-miles long and terminate 20-miles southeast of Stockton. Only two of the five reaches were completed in 1973 and there are currently no funds authorized to finish the project.
As it is the Folsom South Canal has a capacity of 3,500 cubic feet per second. This is the same as the design capacity for the last eight or nine miles of the Friant Kern Canal. One cubic foot per second of flow moves an acre foot of water every 24-hours. At full capacity the Folsom South Canal can move 7,000 a/f per day or 2.5 million a/f per year – if it ran at full capacity – not a likely scenario at this time but it shows what the infrastructure is capable of.
Putting the Canal to Work
Congressman John Duarte has some ideas for utilizing the potential of the FSC. We asked Duarte some questions regarding how this could come about and what that would do for the San Joaquin Valley’s water supply. The following is an edited response.
WW: What is the situation?
JD: The Folsom Reservoir is currently undersized, meaning that during the winter months, December through March, Reclamation must make flood-related releases to create headspace for future snowmelt runoff to prevent overtopping. My understanding is that this released water is not earmarked for downstream users or environmental requirements in
the Delta. My unrefined, rough estimates is that Reclamation makes flood-related releases of about 200K acre/feet on average per year between December and March, but sometimes it is zero and other times it’s as high as 800,000 acre-feet. Just below Folsom Dam is the Folsom South Canal. It has a capacity of 3,500 cubic feet per second but is only used on average at about 40 CFS (yes forty CFS). This canal terminates near Clay Station, CA, in Sacramento County.
WW: What do you propose to do with the FSC?
JD: I would like the Bureau of Reclamation to conduct a General Planning Study (GPS) about extending the Folsom South Canal south to one of four different alignments near the Delta. These Reclamation flood-related water releases during the December to March timeframe could be diverted into an extended canal to be delivered to the Delta region; and building several small off-canal storage facilities along the FSC & extension to capture and hold this water temporarily for when it is needed later in the year.
These flows are not used for environmental purposes in the Delta nor are they earmarked for downstream users. They could be captured and if the canal is extended conveyed to the Delta on to the Central Valley.
WW: Are there things that can be done to improve conditions while waiting for a GPS?
JD: Dredging is important because it restores channel capacity. This allows more water to
flow thru the channels to reduce flood risk, enables more cold water flows to help migrating fish and it potentially allows the Bureau to reoperate their reservoirs to maximize storage so when releases are needed they can do so without risking downstream flooding.
To do this, local stakeholders, the Bureau and the Army Corps of Engineers would work together to dredge rivers and streams in the Central Valley. I was able to include language in the 2024 Water Resources Development Act specifically authorizing the Army Corps to engage in dredging operations with locals in the Valley. (This bill has not been enacted yet.)
WW: What would be the results of this dredging?
JD: Dredging could yield tens of thousands of acre feet of “restored” water (i.e. water that is not lost because of unnecessary flood releases). The Folsom South Canal extension could bring an average (estimated unrefined numbers from Bureau data) 200,000 a/f during the December through March timeframe – annually. That number could be less some years and much higher other years depending on hydrology. Water from the Folsom South Canal extension would likely go to Central Valley Project contractors in the San Joaquin Valley as Folsom is a CVP facility. But this would ultimately be decided by the Bureau.
WW: Any estimates as to the cost of this project?
JD: The cost is unclear both for dredging and the canal extension. It would likely be expensive but that would need to be balanced against the value of the water lost that could otherwise be delivered to our communities. For the canal extension project, the Bureau is working on a rough estimate.
WW: Any idea how long this project could take?
JD: Timing is difficult to estimate because permitting and studies of the canal are needed. The canal project will likely take 10 years or so between studies, permits, private property acquisition and construction.
The plan for the canal is as follows:
- The Bureau conducts a general planning study. This determines if the canal extension is possible, plausible and feasible including water likely available to be sent south and a very rough cost.
- The Bureau would then need to conduct a formal feasibility study of the extension to finalize all the details – water rights, engineering, etc. – that can take several years.
- Then the Bureau would move to construction if the project was found feasible. Both the feasibility study and construction would likely require some congressional action on authorization and funding.
However, the GPS can be accomplished by the Bureau without congressional action. A formal request has been made to the Bureau for a general planning study. We sent a bipartisan letter making the request back in September. The Bureau has acknowledged receipt and is starting to work on it. This study could take 6-18 months.
WW: There has been a flurry of blatant politicization over water policy lately. Is there a way this project can steer clear?
JD: If state permits are required the state could try to slow this down. But whether or not that happens is still to be determined. The California Environmental Quality Act would likely be needed in addition to a federal National Environmental Policy Act review.
There are not too many environmental minuses. The water that would initially go into the canal isn’t tagged for environmental benefits in the Delta. Benefits of the project could include reduced flooding in the region. Once built the canal could pick up additional flood waters from any number of rivers it crosses on its route from Clay Station and the Delta. This would reduce adverse environmental impacts in the region. Also bringing this water to the Delta helps reduce the Valley’s dependence on groundwater, so aquifers could be recharged or subsidence slowed or stopped.
WW: Is this too much common sense for the government to deal with?
JD: This proposed extension of the FSC is worth studying because it could ultimately help us bring more water down the Sacramento-San Joaquin River Delta that could ultimately be delivered to the Central Valley or southern California. Right now, we know that Reclamation is making flood-related water release from Folsom Reservoir in December through March and it mostly flows out to the Pacific Ocean – a waste. This is the reason we want Reclamation to study off-canal storage facilities. When these flood-related releases are being made [December through March] there’s not necessarily demand for that water in in the Valley. So small off-canal storage sites would allow us to hold that water for use later in the year when it’s needed.
Final Note
So, Duarte’s proposal would take a piece of already constructed water infrastructure and improve and expand it and provide more water for recharge in the San Joaquin Valley during the age of SGMA. What could go wrong? Well, one thing that could go wrong is you don’t vote and then complain. If you don’t vote, don’t complain.
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