What Does 15,000 cfs Look Like? – A Perspective from the Freeport Project

For the past several years, the Bay-Delta Conservation Planning process has been studying the potential benefits and impacts of a large “alternative conveyance facility” in the Delta.  Such a facility would run from the northern Delta more than 30 miles to the state and federal pumps in the southern Delta.  There are several design options, including a pipeline, a canal or a tunnel.  Planners have looked at running such a facility along the east side of the Delta, the west side, and under the Delta in a tunnel.  But the maximum proposed capacity of 15,000 cubic feet per second has remained constant. The reason is quite simple.  That’s the maximum combined capacity of the State Water Project and Central Valley Project pumps in the Delta – it's as much as the projects can pump.  (The implications of such a facility are enormous.  I’ve written more about a “Peripheral Canal” here.)

It’s not easy to visualize a 15,000 cfs Delta facility.  The numbers help a little – a canal with this capacity would be approximately a quarter-mile wide – including the canal’s levees.  A tunnel project with this capacity could consist of twin tunnels, each more than thirty feet in diameter. 

The Freeport Regional Water Project, which held a dedication ceremony yesterday, provides a more tangible way to get a sense of the scale of a large Delta facility.  The Freeport facility, which will serve Sacramento County and the East Bay Municipal Utility District, is quite imposing, with large fish screens along the river, a massive pump building, a buried pipeline 7 feet in diameter, along with sedimentation basins, surge tanks and a power substation – all on a six acre site.  A portion of the water pumped here will run east to the Folsom South Canal, and then south until it joins the EBMUD aqueduct from the Mokelumne River to the Bay Area.  (Yes, this means that EBMUD just built a “peripheral pipeline”.)

Here’s what struck me as remarkable about the Freeport project.  This impressive piece of engineering is all for a facility that diverts less than 300 cfs.  That’s a lot of water, but it’s just two percent of the capacity of a large Delta facility.  As the Sacramento Bee points out here a canal or pipeline could require five intakes along the river, each with ten times the capacity of the Freeport Project.  Wow. 

The Freeport project provides another important perspective for the BDCP and the Delta Stewardship Council, as they plan for the future of the Delta.  EBMUD started trying to take water from the American River in 1971.  They faced decades of withering opposition and gridlock.  After a quarter century, EBMUD decided to consider alternatives to their project and ways to build partnerships.  Eventually, EBMUD and the Sacramento County Water Agency accomplished what is thought by many to be impossible – they built a large water project in the Delta with broad support.  

This lesson shows the value of flexibility, alternatives and partnerships.  The final Freeport project looks nothing like the project EBMUD initially envisioned.  The final result has more benefits, broader support and is better for the environment.  This lesson was not lost on the Delta Vision Task Force or on the State legislature.  The former recommended, and the latter required, state agencies to consider a full range of alternative sizes and designs in evaluating conveyance options in the Delta. 

A few weeks ago, State agencies said, in a joint Senate and Assembly oversight hearing, that they would evaluate alternatives to a large canal in the EIR/EIS that will be prepared for the BDCP.  That’s the wrong approach.  A broad range of alternatives must be evaluated carefully in developing the BDCP, not just in evaluating the final proposed project. 

A visit to the Freeport Project is quite thought provoking.  The facility itself is not open to the public, but fortunately, it’s right along the public levee trail in Freeport.  It’s on the southern edge of Sacramento and the northern edge of the Delta.  Go take a look.