Q/A: How does DWR manage water allocations to the state’s public water agencies?


Aerial view looking South at the S Bacon Island road bridge over Middle River, connecting the eastern side of Bacon Island (right) and Jones Tract, both part of the Sacramento-San Joaquin River Delta in San Joaquin County, California. Photo taken March 08, 2019.Ken James / California Department of Water Resources, FOR EDITORIAL USE ONLY

Aerial view of the Sacramento/ San Joaquin Delta. DWR/2019

The business of water allocations – simply put, who receives water from the State Water Project (SWP) and who gets to decide how much – is the subject of two new episodes in the Delta Conveyance Deep Dive video series.  In Part One, State Water Operations Chief Molly White explains the operations and regulations that govern the process of allocating water to the state’s 29 Public Water Agencies and addresses the question of how the proposed Delta Conveyance Project would affect that process.  In Part Two, DWR Water Management Group Chief BG Heiland talks about how DWR works with the state’s 29 public water agencies to supply water to more than 27 million Californians and three-quarters of a million acres of farmland.


Moderator: Patricia Clark, Associate Governmental Program Analyst in the Delta Conveyance Office. 



With Molly White, Chief, State Water Operations


So, Molly, take us through some of the fundamentals of your job.  What are some of the big considerations when it comes to water supply planning and moving water around the state? 

Molly White: You bet.  There are many considerations that we take into account when we are developing our water supply and allocation studies.  I'll talk about a few of those here today.  One significant component is hydrology, and that includes not only rainfall but also snow pack and the runoff forecasts that we receive that show how much water and tell us how much water is coming into our reservoirs as well as how much water is moving through the system as it runs off from the snow pack as it melts in the spring. 

We also take into consideration flood control requirements for Lake Oroville, conditions throughout the State Water Project as a whole, whether it be in our reservoirs or our contractor and water delivery demands.  One significant aspect as well is that we do not operate alone in the Delta.  We jointly operate and coordinate our State Water Project operations with the U.S. Bureau of Reclamation, our federal partner, who operates the Central Valley Project.

In addition, we also take into consideration our senior water rights holders in the Feather River and their water supply and their water demands, as well as another key component, the environmental regulations that govern our diversions from the South Delta. 


So, speaking about environmental regulations, how do these affect how much the State Water Project can divert in the South Delta? 

MW: Let me start by just expanding on what type of environmental regulations that we have that govern some of our operations, especially as they relate to the Delta.  First, we have our water rights permit, which is issued by the State Water Resources Control Board, and we have water quality and flow standards that are required per that permit.  We also have our Incidental Take Permit.  We received that this year from the California Department of Fish and Wildlife, and that sets forth flow requirements in the Delta that are for the protection of state listed species.  As well as we have biological opinions that were issued in 2019 by the National Marine Fisheries Service as well as the U.S. Fish and Wildlife Service, and those also set forth flow requirements for the protection of federal listed species. 

So now let's move on to the Delta and the proposed Delta Conveyance Project.  If the tunnel is built, will it allow DWR to divert more water than is currently allowed by the State Water Board?  As we know, this kind of goes to the heart of the debate about the pros and cons of the project. 

MW: No, Pat, the tunnel would not allow the State to divert more water than what is already allowed under our current water rights permit that has been issued by the State Water Resources Control Board.  With the onset of the operation of the tunnel, just like we do now, there's many key considerations that we take into account when we do our water supply allocation planning.  That rigorous process will still continue and will still account for environmental regulations, hydrology considerations, and also just our joint operations with the Central Valley Project. 

So, if the tunnel is built, how would it change the way that we're able to move water around and through the Delta

MW:  This additional diversion location in the North Delta would provide more operational flexibility that we don't have right now.  Also, with the proposed locations, there are potentially less conflicts with fisheries regulations that exist currently in the South Delta.  The tunnel would also provide additional opportunities to capture additional storm water that may not have been possible without the tunnel.  And lastly, the tunnel would provide a reliable water supply should there be a catastrophic levee failure in the Delta due to a seismic event. 




With BG Heiland, Chief, Water Management Group


The whole topic of water allocations is pretty complicated, to say the least.  So let's start with some of the basics.  How are State Water Project water supplies allocated each year?

BG Heiland: So, we have what's called a contracted Table A amount.  Essentially our contractors sign up via contract to receive a certain allocation every year up to their maximum amount that they contract for and operations will move the water through the system to our contractors all based upon how much rain we get each year within the Feather River Watershed.  There are some slight differences in allocations between those that are north of the Delta versus south of the Delta because it takes a little bit of water to get through the Delta but some of those details get pretty complicated pretty fast. 

Once our contractors receive that water, they have a variety of options looking at transfers or exchanges, and/or looking at augmenting their supplies with non-project water such as water from the Yuba Watershed.

Before we get into how those allocations might be affected by the Delta Conveyance Project, I'd like to back up just a little bit.  And this is really basic, but could you describe for us what exactly a public water agency is and how they operate? 

BGH: Of all the public water agencies in the state, 29 of those agencies contract for water from the State Water Project.  I'll refer to them as contractors.  And for those agencies, the State Water Project may only be one of their sources of water.  There's a large range in size and location for those contractors.  It varies from agricultural districts to large urban suppliers.  Location-wise it goes as far north as Plumas County all the way down to Southern California for the Metropolitan Water District.  For allocation amounts, it could be as small as several thousand acre feet (an acre foot being like a football sized field one foot deep of water) to our largest contractor to 1.9 million acre feet. 

Of the contractors, looking at them overall, about 25 percent of our water is for agricultural and 75 percent is for municipal and industrial.  And each year those contractors are given an initial allocation that operations will regularly update throughout the winter.  The contractors inform my team of their desires given those allocations of when they want their water so we can start looking at the timing of deliveries.  And after the contractors get their initial allocations they have additional options available to them.  The contractors can work amongst themselves with transfers or exchanges from some contractors that may not need all their water in a given year to those that may need a little extra.  And the contracts also allow the contractors to potentially store some of their water in San Louis Reservoir from one year to the next and these tools have evolved and changed over time as we've had various amendments to those contracts.

All right, now to the question of how the allocations to the water agencies would be affected by the Delta Conveyance Project.  If the tunnel is built, how would State Water Project contracts change to accommodate it? 

BGH: All right.  Good question.  So, Pat, with that I just want to clarify that while the deliveries may change for the participating contractors, it will not increase the maximum contracted amount for those water contractors.  We just went through a public negotiation process to get to an Agreement in Principle on Delta conveyance and the Agreement in Principle outlines what changes will be made to those water supply contracts.  Having the Delta Conveyance facility will give the department additional flexibility to move water for those contractors that choose to participate.  This facility will help address the potential impacts of sea level rise and climate change to help us prepare for the future and for those contractors that choose to participate, they will receive a most likely a higher allocation than those contractors that choose not to participate.  But the decision to participate is solely at the discretion of our contractors.

Watch the full interviews.