JFRCalifornia
Keeper of San Juan Secrets
The BOR put out it's latest 24-month forecast for Lake Powell just a few days ago. Not too many obvious new things in there, but there are a few interesting deeper observations that tell you what BOR is thinking might (or might not) happen in 2023 in terms of water conservation in the states. I'll get to that in a minute.
On the upside, BOR upward revised the WY2022 end points for both Powell and Mead compared to what they expected in the spring, probably reflecting the unexpectedly good monsoon season. In the case of Mead, it will be 1044 on September 30, and for Powell it will be 1029. That's 7 feet better for Mead than expected this past spring, and 4 feet better for Powell. That's all good.
On the neutral side of things, they predict a better runoff year in WY2023 than this past year, with an unregulated inflow of 8.3 maf. Still well below average, but an improvement over this year's 6.1 maf, and way better than 2021. Not entirely sure how they derived that number, although historically they tend to be overly optimistic. I hope that's not the case for the coming year.
But here's where there's an interesting (and potentially scary) wrinkle. Recall that in June, BOR called for a 2-4 maf cut in use from the states, or else they said they would do it for them. But so far no action on anyone's part. So I wanted to see if BOR somehow baked in water use reductions into their predicted lake level end points for the end of WY 2023. To test that, I plugged BOR's projected inflow and evaporation numbers into my own spreadsheet model that predicts lake levels. I then plugged in the average Upper Basin water use for the period 2016-20, which is about 4.1 maf. This number essentially would represent a "business as usual scenario", with no new water conservation efforts in the coming year. Here's the interesting result: with my model, I come up with a Sept 30, 2023 water level of 3537.25. That is an almost exact match to BOR's prediction of 3537.20. In other words, BOR is assuming that the states will not be cutting their water use in any way next year. That might be the realistic and conservative approach to making a projection, but it also reflects BOR's lack of desire to push the point on the states and hold them to their June 2022 threat.
What this says to me is that without any outside push on the states from BOR (and it seems there won't be), the states are going to keep using water as they always have. I just hope that BOR's "most probable" scenario is right, because if it's anything worse, there's going to be some big trouble brewing without the states taking a more immediate and decisive approach to serious water conservation... Their "minimum probable" scenario kind of tells this story. In that pessimistic forecast of 4.7 maf inflow (slightly better than in 2021), the lake tops out at just 3510 next summer and drops to minimum power pool (3490) by November 2023. This situation would be avoidable with some serious and immediate water use cutbacks in the Upper Basin, say at least 10-15%, but 30% would be much more effective...
By the same token, cuts of a similar magnitude in the Lower Basin would allow the BOR to release less water through Glen Canyon Dam in 2023 than the 7 maf they plan to because the demand on Lake Mead would be correspondingly less...
By the way, this dynamic of increased conservation and reduced releases to keep the lake levels up is all spelled out in the Plan For 3588, which I'd say is worth a read to anyone at the BOR with an extra 15 minutes on their hands...
On the upside, BOR upward revised the WY2022 end points for both Powell and Mead compared to what they expected in the spring, probably reflecting the unexpectedly good monsoon season. In the case of Mead, it will be 1044 on September 30, and for Powell it will be 1029. That's 7 feet better for Mead than expected this past spring, and 4 feet better for Powell. That's all good.
On the neutral side of things, they predict a better runoff year in WY2023 than this past year, with an unregulated inflow of 8.3 maf. Still well below average, but an improvement over this year's 6.1 maf, and way better than 2021. Not entirely sure how they derived that number, although historically they tend to be overly optimistic. I hope that's not the case for the coming year.
But here's where there's an interesting (and potentially scary) wrinkle. Recall that in June, BOR called for a 2-4 maf cut in use from the states, or else they said they would do it for them. But so far no action on anyone's part. So I wanted to see if BOR somehow baked in water use reductions into their predicted lake level end points for the end of WY 2023. To test that, I plugged BOR's projected inflow and evaporation numbers into my own spreadsheet model that predicts lake levels. I then plugged in the average Upper Basin water use for the period 2016-20, which is about 4.1 maf. This number essentially would represent a "business as usual scenario", with no new water conservation efforts in the coming year. Here's the interesting result: with my model, I come up with a Sept 30, 2023 water level of 3537.25. That is an almost exact match to BOR's prediction of 3537.20. In other words, BOR is assuming that the states will not be cutting their water use in any way next year. That might be the realistic and conservative approach to making a projection, but it also reflects BOR's lack of desire to push the point on the states and hold them to their June 2022 threat.
What this says to me is that without any outside push on the states from BOR (and it seems there won't be), the states are going to keep using water as they always have. I just hope that BOR's "most probable" scenario is right, because if it's anything worse, there's going to be some big trouble brewing without the states taking a more immediate and decisive approach to serious water conservation... Their "minimum probable" scenario kind of tells this story. In that pessimistic forecast of 4.7 maf inflow (slightly better than in 2021), the lake tops out at just 3510 next summer and drops to minimum power pool (3490) by November 2023. This situation would be avoidable with some serious and immediate water use cutbacks in the Upper Basin, say at least 10-15%, but 30% would be much more effective...
By the same token, cuts of a similar magnitude in the Lower Basin would allow the BOR to release less water through Glen Canyon Dam in 2023 than the 7 maf they plan to because the demand on Lake Mead would be correspondingly less...
By the way, this dynamic of increased conservation and reduced releases to keep the lake levels up is all spelled out in the Plan For 3588, which I'd say is worth a read to anyone at the BOR with an extra 15 minutes on their hands...
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