Official lake levels forecast for the coming year (May 24 Month Study)

D

DVexile

Well-Known Member
Powell24MS.png

The May 2026 24 Month Study was just released. This one is interesting because it now includes all the operational changes meant to "save the lake" by keeping the elevation above minimum power pool.

This means:
  • Reduce the release for WY 2026 to only 6.0 Maf
  • Transfer 1.0 Maf from Flaming Gorge through April 2027
If you've been paying attention to threads here already, then there isn't that much new as Wordlings had already adjusted the previous forecasts to include the new operations. But this is the "official" forecast and does indeed show that the BoR operational changes should keep things above minimum power pool until next spring.

Interesting things to note:
  • The "minimum" is somehow slightly higher than the "most probable" through this summer? If you look at the tables themselves it appears the "minimum" forecast actually has slightly higher regulated inflows than the "most probable", in other words in that scenario they release water faster during the summer from upstream sources. Why I have no idea, but it is largely in the noise.
  • The "most probable" forecast for WY2027 assumes 9.16 Maf of unregulated inflow. Wouldn't that be nice...
  • The "minimum" forecast for WY2027 assumes 6.97 Maf of unregulated inflow. For reference, the unregulated inflow for WY2025 and WY2026 combined is only going to be about 8.0 Maf. So that "minimum" for WY2027 is in reality far, far, above what we've just experienced in the past two years.
  • The WY2027 numbers assume either 7.00 or 7.52 Maf of release, but of course they could drop it to 6.0 Maf like they did this year.
Lastly, there is a very strong El Niño forecast. Unfortunately El Niño is not usually a good thing for the upper basin. It can be wet, but it is usually quite warm and results in a low snowpack. Keep in mind, this winter was actually reasonably wet but because it was so warm we ended up with a record low runoff. A similar thing is now more likely for this coming winter if El Niño hits as expected. But there is a lot of uncertainty in such things, and perhaps we can get some summer and fall moisture to help things a bit.
 
I've followed these charts and the overall water situation at powell and throughout the upper basin for the past 5-6 years. It didn't take me long to figure out these forecasts are always wildly optimistic. It's truly laughable. A good rule of thumb, I've found, is take the probable max case and throw it out. That may happen one season, but won't hold throughout the 24 months. Most probable is the probable maximum, and the probable minimum is the most probable. That's how you get a decent forecast across 24 months.
 
I guess I don't understand why they are not metering out upper dam releases in a more measured way -- one that allows safe power generation, but holds as much water as possible higher up where evaporative losses are not as great.

Have I missed something?
 
Trix said:
Well, Rich, did you make a phone call to BOR? A few days ago they throttled back FG outflows from about 8,500 cfs to about 1,250.
Click to expand...
Well they had some wet snow northern Colorado and it melted pretty quick so Lake Powell got a decent amount. Well 30% of average I guess it;s not much but I think that was the reason they held off on more water release from FG for a while.
 
Went to Kanab yesterday. They are watering/growing alfalfa up there like crazy. All the new construction/ a lot, has huge green real grass lawns. Guess since Cali, AZ and Nevada are the only states that have the new cuts in water supplied, its game on for the upper four states.
 
mobius481 said:
I've followed these charts and the overall water situation at powell and throughout the upper basin for the past 5-6 years. It didn't take me long to figure out these forecasts are always wildly optimistic. It's truly laughable. A good rule of thumb, I've found, is take the probable max case and throw it out. That may happen one season, but won't hold throughout the 24 months. Most probable is the probable maximum, and the probable minimum is the most probable. That's how you get a decent forecast across 24 months.
Click to expand...
I'd prefer if we started taking the minimums and treating them like the max, then planning and actually acting around that. Water policy as it is looks like a gambling addict taking on a bunch of credit card debt based on what they think their upcoming slots winnings will be.
 
Trix said:
Well, Rich, did you make a phone call to BOR? A few days ago they throttled back FG outflows from about 8,500 cfs to about 1,250.
Click to expand...
That is part of the plan. They are releasing an average of about 4500 cfs from Flaming Gorge until next April. The 8000 cfs release over about a week was scheduled for supporting a fish species below the dam, now they are dropping to 1000 cfs for about a week to balance out the outflow to 4500 cfs.
 
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