METROPOLITAN IMPORTED WATER COMMITTEE: Challenges ahead for Southern California’s water supplies

A region-wide water allocation will be required should conditions remain dry

Southern California’s water supply news remains dismal, with little good news for Metropolitan’s Imported Water Committee members at Monday’s meeting.  Demetri Polyzos, Team Manager of Resource Planning, gave the update, which included where water supplies are currently at, as well as a look forward to what supplies might be in 2023 and 2024.  The next day, the Metropolitan Board voted on a declaration of drought emergency for Southern California.

The Emergency Water Conservation Program was implemented in April of 2022 when it became clear that there would not be enough water available to meet the projected demand for the areas within Metropolitan’s service area that are dependent on State Water Project supplies.  The program has been successful, with water use just under available supplies (or volumetric limit), as shown by the dashed line.

Metropolitan’s forecasted water demand for 2022 is 1.66 MAF; available supplies are 1.34 MAF, leaving a gap of 322,000 acre-feet, which will be filled by drawing water from storage.  Mr. Polyzos noted that the demand-supply gap was wider earlier in the year, but additional supplies received along with conservation in the State Water Project-dependent areas and throughout Metropolitan’s service area narrowed the gap.

Mr. Polyzos also noted that the Human Health & Safety Allocation of water from the State Water Project comes with an obligation to return the water within five years.  If the State Water Project is 40% or higher in the upcoming years, at least 96,000 acre-feet of water from a previous year must be returned.

Metropolitan staff are projecting to end the year with 2.3 million acre-feet in storage, but where the water is located and the access to that water is critical.  The slide below shows the breakdown of those storage supplies by the three locations: the State Water Project, the Colorado River, and in-basin storage supplies.  The maximum take capacity for each of those three supplies is noted at the top of the box.

We have been drafting on all of the storage programs to help us get and manage through these dry years, and in particular, from the State Water Project where significant withdrawals have been made because of the unprecedented dry conditions and the very low State Water Project allocations,” said Mr. Polyzos.   “On the State Water Project, roughly 95,000 acre-feet will be available from our dry year storage.  You couple that with the initial allocation we received this year, which is 5%.  That combined supply will not get us through the year with the projected demand.  That is why the Emergency Conservation Plan is expected to continue.  That plan was authorized through June of next year.  We’ll need to see that allocation increase much higher than where it has started at 5% before we can end that particular program.”

Mr. Polyzos acknowledged that there has been a lot of rain and snow recently, but it’s still early in the season, and projections for a wet or dry winter are uncertain.  It could go either way, he said.  However, he noted that last year, there was record-breaking precipitation in December followed by record-breaking dry in January, February, and March, so only time will tell.

Planning for future years

With the State Water Project, the final allocation won’t be determined until the spring of next year.  However, on the Colorado River, due to the interim guidelines and DCP obligations, Metropolitan knows what the obligations and contributions would be if conditions remain dry.  However, a lot is happening in the Colorado River Basin, and negotiations may require contributions sooner than 2024.

With the existing agreements, the interim guidelines, and the DCP obligations, we anticipate some level of impacts to our supplies in 2024,” said Mr. Polyzos.  “But whether it’s voluntary on our part that we choose to contribute or not, depending on how the negotiations go, we could see some impacts to our supplies starting as early as 2023.”

This slide below shows the projections for the remainder of 2022, 2023, and 2024 for Colorado River supplies.  Given the uncertainty, a range of supplies is presented.  While the priority 4 water and the transfers and exchanges are relatively known, the uncertainty is in the higher priority use; that number has fluctuated as much as plus or minus 100,000 acre-feet, which would directly impact supply, Mr. Polyzos said.  A small drop in transfers and exchanges is expected in 2023.

In 2024, further reductions in transfers and exchanges are expected, and the range for higher priority water use reflects the staff’s best estimate for the low and high end. 

The Drought Contingency Plan (DCP) contributions are perhaps the most important.  The formula for triggering DCP contributions is known, so given that, the staff estimates that 280,000 acre-feet could possibly be required in 2024.  However, if conditions improve, that might not be necessary.

Keep in mind that the value that ICS brings is not only to help fill up the aqueduct when we need it to, but it also brings some peace of mind that we have that water in storage to satisfy these contributions, not just the contribution for 2024, but beyond.”

But for how long?  The graphic shows the ICS balance if contributions are needed in the upcoming years.  “If we were to satisfy the DCP obligations with the water we have stored in ICS, it would start eating away at that water,” Mr. Polyzos said.

In 2025, there will be enough ICS water to satisfy DCP contributions; however, by 2026, there may not be enough.  Mr. Polyzos emphasized that this is all hypothetical, but it gives an idea of how the water in ICS storage could be used to meet those obligations if conditions remain dry.  So if the water in ICS is earmarked for future DCP contributions, then available storage supplies at the end of 2022 will be only 1.1 million acre-feet in storage. 

In the past, typically, we start talking about a water supply allocation when we are projecting to end that year with about a million acre-feet in storage,” he said.  “That is why we need to discuss potentially moving into water supply allocation next year.”

So, putting the estimates of the Colorado River supplies alongside the State Water Project, the graphic shows the projected total supplies for 2023 and 2024.  Mr. Polyzos emphasized that there is a lot of uncertainty with aspects of each line item, so again, a range of values is presented.

The bottom line is when you put together the State Water Project supply assumptions with Colorado River assumptions, and then balance that out with demands on Metropolitan and all the other additional obligations that we have, we could expect in 2023, a supply-demand gap of minus 520,000 acre-feet to 725,000 acre-feet on the positive,” he said.  “It’s not always all negative.  We are focused on the negative because that’s what we’re dealing with right now.  But if things can improve, and if they did, we could see ourselves in a position where we would be putting water into storage.”

In 2024, the potential gap or surplus widens a little bit,” he said, noting that many details are in the notes about the assumptions.

Preparing for 2023

Staff is working on the assumption dry conditions will continue, so they are protecting existing supplies and pursuing supplemental supplies for the entire service area.

This isn’t a business-as-usual approach,” said Mr. Polyzos.  “We are in unprecedented times, so we’re going to be turning over every rock; we’ve already started to do that.  Not just for this year but certainly for next year, we’re working to squeeze out as much water as possible.  So we continue to support the development of new supplies, whether supporting our ILRP or Pure Water Southern California.”

Staff will also be pursuing new transfer supplies much more aggressively and will ask the Board next month for authorization to seek supplies throughout the state.   “In fact, we’re going to be pursuing them in a much more aggressive manner than what we typically do,” he said.

Staff is working to maximize groundwater banking programs on the State Water Project and Colorado River groundwater storage withdrawals.

Key takeaways

  • Both imported water supplies are experiencing unprecedented challenges.
  • Uncertainty in hydrologic conditions and potential rules and obligations leads to a range of possible outcomes.
  • Metropolitan is preparing for a fourth year of drought and continues to pursue supplemental supplies and protect existing supplies.
  • Metropolitan is not planning a full Colorado River Aqueduct for 2023 or beyond.
  • The use of ICS to meet future DCP contributions alleviates potential reduction in future Colorado River diversions.
  • Discussions are now beginning for the implementation of a possible water supply allocation for Metropolitan’s entire service area.
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