Returning to Elevation 3588 in Lake Powell – Can It be Done?

JFRCalifornia

Escalante-Class Member
Oh, I get the significance of that elevation now. Thanks. Can we see that in your lifetime? Or even in mine?
If USBR reduced the outflow through Glen Canyon Dam by 30% right now, we'd see 3588 next year. The trade-off is that Lake Mead would drop like a rock, Hoover Dam power generation would be jeopardized, and the Lower Basin states wouldn't get all the water they're used to getting. But anything is possible if you're willing to accept trade-offs and change the rules to allow it to happen.

There's a precedent for this. In 1964, USBR reduced flows through Glen Canyon Dam all summer long to about 1000 cfs (about 10% of the current outflow) in an effort to make Lake Powell fill faster. It worked. Between May and August 1964, Lake Powell rose by 95 feet. At the same time, with river flows through the Grand Canyon reduced to a trickle, Lake Mead dropped 25 feet--about a foot every four days. So it's possible. It's all just a matter of priorities.

So will we see 3588 in my lifetime? Sure. Maybe even in yours.
 

Gunny

Active Member
Longer growing season for profitable crops, not that hard to understand with plentiful water. I also like to visit my aunt in Phoenix around January when it's freezing in SW Colorado. Unfortunately, recent history has proven that water isn't always plentiful. Now we know how the Anasazi felt(but they didn't have as much technology, or reservoirs).
So selfish greed. They fit into our society well.
 

Trix

Escalante-Class Member
After reading full report and rereading this thread, my light bulb take away is that we don't need an unprecedented period of high snowpack to restore lake to levels I have enjoyed for 5 decades. My notion was we needed something like multiple years of 150+% snowfall to get back to 3600ish. As John has demonstrated, 20% above 2016-2020 average is not unprecedented and gets the lake back to "normal."
I know the climate alarmists tell us the western megadrought is the new normal (forget that a warmer atmosphere holds more water nonsense), but John's analysis gives me honest hope that the kids can yet throw the old man onto the transom seat and cruise through The Cut before my ashes are spread in Dungeon Canyon.
 

Greg Archer 71

Active Member
Since the beginning of 2020, Lake Powell, like the sun in the late afternoon, sometimes appears to be slowly sinking over the horizon. With all the recent reports of impending doom from continued drought, and just seeing things with your own eyes, it’s easy to believe this trend will go on forever until nothing of the lake is left at all. And yet, it’s just as easy to forget that 2019 was a banner year for Lake Powell, one in which it rose 53 feet that spring. That wasn’t so long ago, but right now it sometimes feels like an eternity.

Rather than focus on the extremes to predict a future outcome, its sometimes helpful to focus on the average. The mundane. The ordinary year. And with that concept in mind, I wanted to figure out the answer to this question: What would it take to make Lake Powell rise again, and then stay there? To make the marinas, launch ramps, the Castle Rock Cut—all of the key recreational infrastructure—usable and viable for the long haul? And practically speaking, that means this: what would it take to keep the lake over elevation 3588? That’s the target elevation identified by Fill Lake Powell that would achieve those goals.

Figuring that out is a tall order, and depends on many factors, some of which can’t be controlled (like the snowpack), but some of which can (like water use). And of course to really solve that puzzle, you’ve got to consider the entire system—not just Lake Powell, but Lake Mead too. And the other smaller reservoirs. Not just water use in the Upper Basin, but all seven states and Mexico too. It’s complicated. But as with any complicated puzzle, it’s best to take it one piece at a time, and eventually you will fill in the blanks. Complete the picture. Solve the problem. Or at least identify what it would take to solve the problem. And from there, you can change the way things have always been done into the way they need to be done.

All that means, for our purposes, starting by focusing on Lake Powell. I’ll save Lake Mead and the Lower Basin for another day.

Where to begin? For all the numbers that can be run, the “what-if” scenarios that can be considered, it’s best just to simplify that challenge.

It’s basically just a simple question of inflow vs. outflow.

Let’s first consider outflow. For Lake Powell, there’s really three important factors to consider, but here’s the only one that really matters: USBR’s releases through Glen Canyon Dam. Sure, there is also a small amount directly used from Lake Powell by the city of Page, and then there are evaporative losses from the lake, but both are orders of magnitude less than what flows through the dam. And then, yes, there is the theoretical drain from future water diversion projects not yet online, and perhaps never will be, such as the proposed pipeline to St. George.

With the exception of evaporative loss, all those are controllable factors.

And then on the inflow side, snowpack (precipitation in general) is by far the most important issue, but unlike outflow through the dam, this is out of anyone’s control. There are also other important considerations: the amount of water diverted to serve the needs of the Upper Basin states, and the amount of water available for release stored in the reservoirs above Lake Powell. Unlike the snowfall, these are controllable factors.

In May 2022 the USBR issued its latest 24-Month Study, which forecasts inflows and outflows for all reservoirs affecting the entire Colorado River watershed. The forecast is based in part on projected long-range precipitation forecasts, historic trends, and projected releases from each reservoir. The forecast extends through May 2024, or roughly midway through Water Year 2024 (WY 2024).

Based on this, and other existing USBR documentation, I developed sixteen scenarios to model what could happen to Lake Powell depending the various factors described above related to inflow and outflow. The most important of these factors is how much total water would be available in the system before anybody uses or stores it. In a simplified model, this number is possible to reverse engineer from existing reported data:

Total Water Availability = Inflow to Lake Powell + Upper Basin Water Use + Upper Basin Additional Storage + Upper Basin Reservoir Evaporation

My report goes into some detail about what those mean and the assumptions behind them, but I'll leave that to those interested in reading the full report.

And then there’s the question: what should be considered a baseline “average” year for modeling purposes? Is it the historic average inflow since Lake Powell came into existence? That seems too broad. Or maybe the period USBR focuses on to establish an “average” inflow, which is 1991-2020? Or should it be something more recent, reflecting the observed realities closer to our time? For example, the 5-year period 2016-20 was a very “average” time in the life of the lake. In terms of inflow, it featured two good years (2017 and 2019), two bad years (2018 and 2020), a pretty average year (2016). In all, the average inflow to Lake Powell during that time was about 8.99 maf, which is a little less than the USBR’s reported 1991-2020 average of 9.6 maf. Based on that, it’s reasonable to use the 2016-20 period as a more conservative “baseline average”, because it would tend to produce less optimistic results when projecting percentage increases (or decreases) from that baseline. It’s also a period where we have very detailed and realistic recent water use data for both the Upper and Lower Basins. For all these reasons, the period 2016-20 is what is used as the baseline “normal” for the purposes of this study.

Based on the assumptions described below, the Total Water Availability in the Upper Basin on average from 2016-20 was 13.6 maf.

What went into developing the various modeled scenarios? Were they just arbitrary? Spitting into the wind?

Sixteen scenarios were developed to predict what would happen to Lake Powell’s surface elevation through Water Year 2027 (WY 2027). Each of these varied one or more of the factors discussed above. In general, these scenarios considered a range of future Total Water Availability via snowpack, from 40% less than the 2016-20 average, to 20% more than average (something like what happened from 1996-2000). Within many of those scenarios, consideration was given to reducing existing Upper Basin Water Use anywhere from 5% to 50% in order to test the sensitivity of that variable and its effect on creating more downstream inflow potential to Lake Powell. Or increasing (or decreasing) flows from the upper reservoirs such as Flaming Gorge. Or varying the outflow through Glen Canyon Dam, although in general, I tried to adhere to existing USBR protocols for that. No effort was made to address Lower Basin water use or effects on Lake Mead in general. While those are extremely important considerations in the big picture, I left them for another time. But they are important.

And without getting into how the sausage was made, I'll cut to the key conclusions of the study, some obvious, some less so:

1. The most important factor in maintaining Lake Powell’s volume is total water availability, primarily through snowpack in the Upper Basin.

2. If the next 5-year period (WY 2023-27) matches the total water availability that occurred from 2016-20 (a very modest goal in historic terms), it is possible to achieve the target elevation of 3588 during WY 2025, although it would require a 5% reduction in Upper Basin water use during that time.

3. It is possible to achieve the target elevation of 3588 in WY 2025 even with a 5-year period with 5% less available water than in 2016-20. But it would require a 5-10% decrease in Upper Basin water use, and potentially additional releases from Flaming Gorge and other Upper Basin reservoirs that could further reduce capacity in those lakes.

4. In any scenario, reducing Upper Basin water use by 10% could add 400,000 AF to Lake Powell each year, which would raise the lake annually 5-6 feet by itself.

5. If the watershed sees a 5-year period of water availability similar to what occurred in 2000-04, which was about 40% less than the 2016-20 average, the outlook is grim. Only substantial reductions in Upper Basin water use and releases from upstream reservoirs (particularly Flaming Gorge) would allow Lake Powell to avoid hitting the dead pool elevation of 3370 in WY 2025. With this sort of 5-year flow regime, it would be impossible to avoid dropping below the minimum power pool of 3490, no matter what was done short of drastically reducing outflows through Glen Canyon Dam to the point of jeopardizing water deliveries to the Lower Basin and power production through Hoover Dam.

6. Conversely, with a 5-year period of water availability 20% above the 2016-20 average (similar to what happened in 1996-2000), it would be possible to fill Lake Powell to 3700 by 2027, provided that outflows through Glen Canyon Dam are generally limited to 8.23-9.00 maf, rather than the larger releases that typically occur in such higher flow years in support of increasing the volume of Lake Mead.

What this all says is that the watershed is a highly dynamic system, and very sensitive to what happens in any five-year period. Long-range precipitation forecasts in the southwest are generally not optimistic, and for that reason, we need to prepare with open eyes for what might happen in if we see another period that matches what we saw in 2000-04. On the other hand, it really doesn't take much to turn things around--even a return to the period 2016-20 could work. We just don't know at this point, but need to think ahead to consider different possible outcomes.

If you want to read the entire analysis with all its mundane details, have at it. It's 13 pages long, and that's leaving out all the original spreadsheets. I'm going to guess there's about five of you who will want to read the whole report...

Here it is:

Interesting stuff. Shouldn't you be dumping all this on the desks of the BoR? They might even give you a job.
 

Gunny

Active Member
It’s feasible that the lake could refill in just a few years.
And hopefully NOT at the expense of Lake Mead nor the upstream reservoirs. What would happen to these two big reservoirs if we killed California's water for one year? Anybody?
 

flowerbug

Well-Known Member
And hopefully NOT at the expense of Lake Mead nor the upstream reservoirs. What would happen to these two big reservoirs if we killed California's water for one year? Anybody?

you would have to stop Arizona too as i doubt that CA would accept such a move if AZ didn't. from those combined you'd get about 7maf change in both combined so it again all comes up to how much inflow you get along with such a move. of course wild-a$$ed guessing, that's really not a huge bump but it would help bring them up off the lows.
 

JFRCalifornia

Escalante-Class Member
And hopefully NOT at the expense of Lake Mead nor the upstream reservoirs. What would happen to these two big reservoirs if we killed California's water for one year? Anybody?
I'll answer that one another way. What if every state reduced their use of river water by 10% from their average use from 2016-20? And Mexico did the same? And the total available water in the system was similar to the average from 2016-20?

Still working on detailed numbers for that one, but here's the rough analysis. First, the key data:

Average Annual Water Use, 2016-20:

Lower Basin - 6.9 maf
Upper Basin - 4.1 maf
Assume Mexico gets 1.5 maf

Evaporation (annual), 2016-20:

Lower Basin - 0.54 maf
Upper Basin - 0.47 maf

Input below Glen Canyon Dam (from Little Colorado and Virgin rivers) - 0.89 maf

Assume average annual release (from 2023-27) through Glen Canyon Dam of 8.23 maf.

If you reduced all parties water use by 10%, but kept evaporation the same, and assumed total water availability similar to 2016-20, here would be the September 30 elevations of Powell and Mead from WY 2023 to WY 2027:

Lake Powell -

2023 - 3546
2024 - 3563
2025 - 3579
2026 - 3593
2027 - 3605

Lake Mead -

2023 - 1051
2024 - 1065
2025 - 1078
2026 - 1089
2027 - 1101

You can see it doesn't take a lot to get both lakes to rise, but it does require the collective will to reduce water use on the part of all states (and Mexico), plus average luck in terms of snowpack--just meet the 2016-20 average, which is about 6% less than the average from 1991-2020. In other words, doable. I'm working out the "what ifs" of what would need to be done if snowpack remains terrible (as in 2021), but it's not hard to see that with a little effort on the part of the states and some modest snowpack luck, both lakes can see a rise over the next few years. And with actual good snowpack and continued water conservation, the rise can be dramatic...

More detailed numbers to come soon...
 
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Colorado Expat

Well-Known Member
I'll answer that one another way. What if every state reduced their use of river water by 10% from their average use from 2016-20? And Mexico did the same? And the total available water in the system was similar to the average from 2016-20?

Still working on detailed numbers for that one, but here's the rough analysis. First, the key data:

Average Annual Water Use, 2016-20:

Lower Basin - 6.9 maf
Upper Basin - 4.1 maf
Assume Mexico gets 1.5 maf

Evaporation (annual), 2016-20:

Lower Basin - 0.54 maf
Upper Basin - 0.47 maf

Input below Glen Canyon Dam (from Little Colorado and Virgin rivers) - 0.89 maf

Assume average annual release (from 2023-27) through Glen Canyon Dam of 8.23 maf.

If you reduced all parties water use by 10%, but kept evaporation the same, and assumed total water availability similar to 2016-20, here would be the September 30 elevations of Powell and Mead from WY 2023 to WY 2027:

Lake Powell -

2023 - 3546
2024 - 3563
2025 - 3579
2026 - 3593
2027 - 3605

Lake Mead -

2023 - 1051
2024 - 1065
2025 - 1078
2026 - 1089
2027 - 1101

You can see it doesn't take a lot to get both lakes to rise, but it does require the collective will to reduce water use on the part of all states (and Mexico), plus average luck in terms of snowpack--just meet the 2016-20 average, which is about 6% less than the average from 1991-2020. In other words, doable. I'm working out the "what ifs" of what would need to be done if snowpack remains terrible (as in 2021), but it's not hard to see that with a little effort on the part of the states and some modest snowpack luck, both lakes can see a rise over the next few years. And with actual good snowpack and continued water conservation, the rise can be dramatic...

More detailed numbers to come soon...
Trying to get another 10 percent reduction in water use across all the Compact states is going to be a heavy lift, given that we are not starting with a base of profligate water use anymore. In fact, many of the Compact states have undertaken significant water conservation programs over the past couple of decades, so the easy fixes are now gone. In addition, the Upper Basin states seem to be increasingly concerned that they are never going to be able to utilize what they see as their fair share of the river (traditionally viewed 7.5 maf, although that is clearly not codified or guaranteed), so are adopting a use-it-or-lose-it approach (witness several new trans-basin diversion proposals recently discussed in this forum). So the best you might get out of Colorado, Wyoming, and New Mexico is status quo on current use, and more likely modest increases. Utah is a different matter, since they want Lake Powell fuller into order to build the pipeline to St. George.

Then there is the question of the tribes. On 27 May, Secretary of the Interior Deb Haaland and Assistant Secretary for Water and Science Tanya Trujillo joined Senator Mitt Romney, Utah Governor Spencer J. Cox and Lt. Governor Deidre Henderson, and Navajo Nation President Jonathan Nez at a press conference in Monument Valley to sign the Navajo-Utah Water Rights Settlement Agreement. To quote the press release, this agreement will:

“...help ensure the Navajo Nation has adequate drinking water infrastructure, the agreement affirms the Nation’s right to use 81,500 acre-feet of water per year from the San Juan River. This will protect existing water uses and support future development in this community.

The agreement also provides over $200 million in federal funding, which will be provided from the Bipartisan Infrastructure Law, and $8 million in state funding for water infrastructure development on the reservation. Overall, the Bipartisan Infrastructure Law includes a $2.5 billion investment to implement the Indian Water Rights Settlement Completion Fund, which will help deliver long-promised water resources to Tribes, certainty to all their non-Indian neighbors, and a solid foundation for future economic development for communities dependent on common water resources.”

So that is a completely foreseeable increase in Upper Basin use right there, and there will be more straws in both the upper and lower river as more of this water infrastructure for the tribes throughout the Colorado system is built out over the next 5 years.

The bottom line here is that I just do not realistically see a 10 percent reduction in Upper Basin use of the Colorado River system. If anything, it will be quite the opposite.
 

JFRCalifornia

Escalante-Class Member
Trying to get another 10 percent reduction in water use across all the Compact states is going to be a heavy lift, given that we are not starting with a base of profligate water use anymore. In fact, many of the Compact states have undertaken significant water conservation programs over the past couple of decades, so the easy fixes are now gone. In addition, the Upper Basin states seem to be increasingly concerned that they are never going to be able to utilize what they see as their fair share of the river (traditionally viewed 7.5 maf, although that is clearly not codified or guaranteed), so are adopting a use-it-or-lose-it approach (witness several new trans-basin diversion proposals recently discussed in this forum). So the best you might get out of Colorado, Wyoming, and New Mexico is status quo on current use, and more likely modest increases. Utah is a different matter, since they want Lake Powell fuller into order to build the pipeline to St. George.

Then there is the question of the tribes. On 27 May, Secretary of the Interior Deb Haaland and Assistant Secretary for Water and Science Tanya Trujillo joined Senator Mitt Romney, Utah Governor Spencer J. Cox and Lt. Governor Deidre Henderson, and Navajo Nation President Jonathan Nez at a press conference in Monument Valley to sign the Navajo-Utah Water Rights Settlement Agreement. To quote the press release, this agreement will:

“...help ensure the Navajo Nation has adequate drinking water infrastructure, the agreement affirms the Nation’s right to use 81,500 acre-feet of water per year from the San Juan River. This will protect existing water uses and support future development in this community.

The agreement also provides over $200 million in federal funding, which will be provided from the Bipartisan Infrastructure Law, and $8 million in state funding for water infrastructure development on the reservation. Overall, the Bipartisan Infrastructure Law includes a $2.5 billion investment to implement the Indian Water Rights Settlement Completion Fund, which will help deliver long-promised water resources to Tribes, certainty to all their non-Indian neighbors, and a solid foundation for future economic development for communities dependent on common water resources.”

So that is a completely foreseeable increase in Upper Basin use right there, and there will be more straws in both the upper and lower river as more of this water infrastructure for the tribes throughout the Colorado system is built out over the next 5 years.

The bottom line here is that I just do not realistically see a 10 percent reduction in Upper Basin use of the Colorado River system. If anything, it will be quite the opposite.
Very well said, your analysis is right on the mark...which lays out the challenge before us all... a big challenge, but so is building a dam.
 
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Trix

Escalante-Class Member
Trying to get another 10 percent reduction in water use across all the Compact states is going to be a heavy lift, given that we are not starting with a base of profligate water use anymore. In fact, many of the Compact states have undertaken significant water conservation programs over the past couple of decades, so the easy fixes are now gone. In addition, the Upper Basin states seem to be increasingly concerned that they are never going to be able to utilize what they see as their fair share of the river (traditionally viewed 7.5 maf, although that is clearly not codified or guaranteed), so are adopting a use-it-or-lose-it approach (witness several new trans-basin diversion proposals recently discussed in this forum). So the best you might get out of Colorado, Wyoming, and New Mexico is status quo on current use, and more likely modest increases. Utah is a different matter, since they want Lake Powell fuller into order to build the pipeline to St. George.

Then there is the question of the tribes. On 27 May, Secretary of the Interior Deb Haaland and Assistant Secretary for Water and Science Tanya Trujillo joined Senator Mitt Romney, Utah Governor Spencer J. Cox and Lt. Governor Deidre Henderson, and Navajo Nation President Jonathan Nez at a press conference in Monument Valley to sign the Navajo-Utah Water Rights Settlement Agreement. To quote the press release, this agreement will:

“...help ensure the Navajo Nation has adequate drinking water infrastructure, the agreement affirms the Nation’s right to use 81,500 acre-feet of water per year from the San Juan River. This will protect existing water uses and support future development in this community.

The agreement also provides over $200 million in federal funding, which will be provided from the Bipartisan Infrastructure Law, and $8 million in state funding for water infrastructure development on the reservation. Overall, the Bipartisan Infrastructure Law includes a $2.5 billion investment to implement the Indian Water Rights Settlement Completion Fund, which will help deliver long-promised water resources to Tribes, certainty to all their non-Indian neighbors, and a solid foundation for future economic development for communities dependent on common water resources.”

So that is a completely foreseeable increase in Upper Basin use right there, and there will be more straws in both the upper and lower river as more of this water infrastructure for the tribes throughout the Colorado system is built out over the next 5 years.

The bottom line here is that I just do not realistically see a 10 percent reduction in Upper Basin use of the Colorado River system. If anything, it will be quite the opposite.
FWIW, I viewed JFR's 10% user reduction as just scenario 17, not a recommendation or expectation.
 
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