Disproving Myths About the CVP's 2017 Water Allocation

Perhaps I should not be surprised that some irrigation districts and special interest groups representing corporate agribusinesses are twisting the facts to complain about the federal Central Valley Project’s “mere” allocation of 8.8 million acre feet of water for 2017, the vast majority of which goes to agriculture. That’s enough water to submerge the entire state of Connecticut with more than 2 feet of water, and is equivalent to an allocation of 92.7% of the maximum contract amounts of 9.5 million acre feet of water.   

To be fair, they would rather that the public and decision-makers ignore all of the irrigation districts, cities, and water rights holders who are getting a 100% allocation from the Central Valley Project this year (see table above and here). They would rather focus solely on the Westlands Water District and other South of Delta agricultural water service contractors, who are generally the last in line for water from the Bureau of Reclamation, and which constitute less than a quarter of the total water allocations from the Central Valley Project.   

Why the CVP Allocation for Westlands Water District Is Currently 65%

(1) Fact: Westlands admits it’s not the ESA or environmental laws. San Luis Reservoir is full (but not all the water in federal storage is included in the CVP allocation)

As Maven has reported, Reclamation officials say carryover storage is to blame, not endangered species regulations. While some try to blame the allocation announcement on protecting salmon and other native fish species, Reclamation staff explained on their briefing call with reporters that, “We’ve had very little constraints as it relates to operations for protecting listed or endangered species, so that’s really not the limitation here. It’s really the plumbing…”  

Even the Westlands Water District recently admitted that, “it is correct that because of the extremely wet hydrology, the ESA and other regulations have not restricted CVP operations in 2017.” In the past few years, protections for Delta Smelt have had little to no impact on water supply, as drought was the overwhelming cause of reductions in water supply (protections for endangered salmon have had some impacts on supply, but even those impacts were small compared to hydrologic changes). 

Pumping from the Delta has slowed dramatically in recent weeks, because San Luis Reservoir was filled completely with water (in addition, after filling the state side of San Luis Reservoir, the State Water Project pumps shut down for emergency repairs). Despite Reclamation making additional water available for irrigation districts and cities if they can store or use it now, very few people are purchasing this water, causing pumping to slow.  

But not all of the water in the federal side of San Luis Reservoir is water that counts towards the CVP allocation.  Some of it is what’s known as “carryover water.” Last year, some South of Delta irrigation districts purchased water on the market (a water transfers), and they chose to store that water in San Luis Reservoir (it is known as “carryover water,” because water users choose to carry over the water to the next year). These water users choose to use the federal reservoir to store their water even though they knew that if San Luis Reservoir filled with water from the CVP and SWP, their water would be spilled in order to make room to store water for all of the CVP contractors (which is the primary purpose of this reservoir). According to staff from the Bureau of Reclamation, nearly 30% of the water in federal storage in San Luis Reservoir was carryover water; as the Sacramento Bee story explained, this water does not count towards the CVP allocation but is still part of those users’ s supply.   

Alert readers may remember that in early 2013, NRDC included additional south of Delta storage as part of our Portfolio Alternative for the Bay-Delta, recognizing that in these really wet years (like 2011), there’s the ability to pump more water but no place to put it; our Portfolio Alternative recognized that water users could use some of the $5.9B in cost savings from a single tunnel alternative to fund improvements in south of Delta storage, local and regional water supply projects like water recycling, and levee improvements. While other water users have built their own storage projects, including Los Vaqueros Reservoir (Contra Costa Water District) and Diamond Valley Reservoir (Metropolitan Water District of Southern California), the CVP contractors carrying over water in San Luis Reservoir rely on taxpayer subsidized infrastructure, instead of paying for their own water storage.

200,000 acre feet of carryover water would be equivalent to more than a 10% increase in the CVP allocation for South of Delta agricultural contractors. While that carryover water may not count towards the CVP allocation, it is substantial additional water for these CVP contractors. 

(2) FACT: Westlands’ share of Delta water has declined in recent years, as the State Water Project has increased pumping.

Although this has been less of an issue so far this year, part of the reason why Westlands and other CVP contractors were able to export more water in the past was that the State Water Project was not using its full capacity. Until the 1990s, the Metropolitan Water District of Southern California was not demanding its full allocation from the Delta, and as a result, the CVP was able to use the larger State Water Project pumps to export water for CVP contractors like Westlands. The Public Policy Institute of California estimates that the share of water from the Delta going to the San Joaquin Valley has decreased by around 500,000 acre feet per year as a result of increased demand by SWP contractors. So even though combined CVP/SWP exports of water from the Delta on average are the same today as the 1980 to 2000 average, there is less water going to Westlands and other CVP contractors south of the Delta.  


Source: Public Policy Institute of California 2017, page 22

In addition, according to data from the Bureau of Reclamation (see table 2-25), State Water Project facilities in the Delta have historically been used to pump water to CVP contractors like Westlands. In some years as much as 500,000 acre feet of water were pumped by the SWP for CVP contractors, although that has slowed in recent years as SWP demands for delta water have increased. 

In fact, since 1976 the federal Tracy pumping plant in the Delta has never pumped enough water in a single year to deliver the more than 3.2 million acre feet of water necessary to meet full CVP allocations for all South of Delta contractors: 

Maximum Historic CVP Tracy Pumping

Maximum South of Delta CVP Contract Allocations

2.94 million acre feet (calendar year 1989)


3.259 million acre feet (includes SOD Ag, SOD M&I, Refuge Level II, and Exchange Contractors)

Even in recent wet years (like 2006 and 2011), the CVP’s Tracy Pumping Plant exported less than 2.8 million acre feet from the Delta.  In order for the CVP to deliver the more than 3.2 million acre feet of full water allocations for all of its South of Delta contracts from the Delta, the Tracy Pumping Plant must run at 4,600 cfs for more than 357 days in a year. It does not appear that the CVP can physically pump at that capacity for a full year, even under perfect hydrological conditions. So with increased SWP demand, and reduced access to SWP facilities to move CVP water, deliveries to Westlands and other CVP contractors have been reduced over time. Indeed, back in 2011, the CVP and SWP exported record amounts of water from the Delta, but it did not result in a 100% allocation to all CVP and SWP contractors. 

(3) FACT: Westlands’ CVP Allocation is likely to increase over the course of the year.

The initial water allocation from the Bureau of Reclamation is conservative, with a 90% chance that the allocation will stay the same or increase over the course of the year (what’s known as a 90% exceedance forecast). Reclamation reminds the media and stakeholders of this each year, but it often gets lost in the shuffle. Water users like Westlands know this, and just this week Westlands informed their growers that they anticipate the allocation may increase by 10-15% this year. The allocations are conservative because it’s far worse to have to reduce the allocation over the course of the summer planting season than it is to increase the allocation. While some have complained about higher allocations in 2006 or 2011 (other recent wet years), they ignore the fact that in March of those years, the allocation was lower than it is in 2017. This is true of years both before and after biological opinions in the Delta. 


CVP Allocation in March for South of Delta Ag

Final CVP Allocation for South of Delta Ag





55% (March 22, 2011)

65% (March 28, 2011)



65% (increased to 85% on April 20, 2006)



65% (increased to 70% on April 15, 2005)


Source: Bureau of Reclamation

I suppose I shouldn’t be surprised to see Westlands and their allies twisting the facts to complain about this year’s allocation, but the facts simply don’t back up their complaints.