RobertGosselin
Well-Known Member
Interesting. Where did you get the info on the May 4 release? Is it just a one day release?
How much do we expect the lake to rise this spring/summer
- Thread starter doc
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I think your projects may be a little rosy. Inflow of water to Lake Powell is 25% of average and that based on in inflows continue at 6621. Where in the past five days they ranged from 3143 - 4105.Scientists have warned for a long time about climate change and the South west has been in a severe drought for twenty plus years. I think it was two years ago that the mountains received some snow and people laughed and said climate change is a hoax. People even talked about running a pipeline and pump water from either the Mississippi river or the Great Lakes to Lake Powell. Something so ridiculous it's hard to believe a comment like that would be made.
RobertGosselin
Well-Known Member
The planned releases from Flaming Gorge (already underway) and the reduction in outflow at the Glen Canyon Dam (also underway) will keep the lake at the levels described in JFR's post. He states those reasons as a basis for his projections.
Flaming Gorge | Water Operations | UC Region | Bureau of Reclamation
Bureau of Reclamation - Managing water and power in the West
And you can see the planned releases out for a couple of weeks here:
That shows the 8600 cfs release running at least until May 11th. I haven't tracked down any statement about how long the release is planned for beyond that.
RobertGosselin
Well-Known Member
Thanks for the info and the links. I've been messing around with the Lake Powell Water Base, delving into some of the mountains of information there but had not reached this point yet. It appears that the 8K+ release will continue until, at least, the 12th. That should result in a stretch of green on the LP water level chart for a similar length of time about May 13 to the 21 and maybe beyond! I launch on June 3 and if it is still in the green by then, I will be thrilled. Maybe we will see less muck on the beach landings in Oak Bay where we usually stay on the first day of our trip.Flaming Gorge | Water Operations | UC Region | Bureau of Reclamation
Bureau of Reclamation - Managing water and power in the Westwww.usbr.gov
And you can see the planned releases out for a couple of weeks here:
That shows the 8600 cfs release running at least until May 11th. I haven't tracked down any statement about how long the release is planned for beyond that.
RobertGosselin
Well-Known Member
Whoops! Change that to May 11 to 19. I was using 9 days for the journey from FG to LP but it is 7 days as you have stated.
doc
Active Member
Great info. So, we should see the effect on LP in a little over a week. It'll be interesting.Flaming Gorge | Water Operations | UC Region | Bureau of Reclamation
Bureau of Reclamation - Managing water and power in the West
And you can see the planned releases out for a couple of weeks here:
That shows the 8600 cfs release running at least until May 11th. I haven't tracked down any statement about how long the release is planned for beyond that.
Well were 58% through the water year already. Yet we have only released the 48% of the minimum required to date.
You’re using the wrong minimum and will need to keep up to date with reality if you are going to contribute anything useful to the thread:
JFR has been keeping up, which is why his numbers make sense and yours are wrong. We are at 60% of the release for this WY.
doc
Active Member
The BOR article is concise and informative.You’re using the wrong minimum and will need to keep up to date with reality if you are going to contribute anything useful to the thread:
JFR has been keeping up, which is why his numbers make sense and yours are wrong. We are at 60% of the release for this WY.
Trix
Keeper of San Juan Secrets
It’s kind of a shame that BOR didn’t ramp up FG releases to full turbine output of about 4,000 cfs sooner than this week. That would have put more cheap hydropower on the grid, although system loads are pretty low this time of the year. Releases now of about 8,000 cfs means “wasted” water going through the outlet works. I wonder if there is concern about possible damage from consistent flows through FG outlet works as has been mentioned somewhere in our discussions of sustained flows through GC outlet works.
Interesting thread, glad there is more water headed our way.
Interesting thread, glad there is more water headed our way.
They are using the bypass to intentionally create a high flow for a "larval trigger study".
Here's some info about when they did a similar thing back in 2022:
Since earlier in the thread we were talking about the CBRFC runoff forecast methods, and their some time disconnect from reality, I thought I'd post today's GEFS based forecast:
There's at least a 10% chance that water will flow back up the Colorado from Powell!
So we can tell that "observed accumulation" is clearly NOT an input to the forecast model...
What this really illustrates is just how far out of family this year is from anything in the past. Often times models don't include inputs that seem "obvious" to us because in more "normal" times they don't actually improve the model forecasting ability. As another poster pointed out a few weeks ago this means the models can run amok when we get into weird times. Earlier in the season the climatological ensemble forecasting seemed to be very clearly biased high. Now, later in the season, we are seeing the bottom end of the ensemble resulting in a different kind of nonsense (some other folks pointed out the bottom end seemed unrealistically pessimistic a few weeks ago as well, but now it is to the point the numbers don't even add up).
Anyway, the CBRFC forecast is sort of moot at this point. The runoff is going to be extremely low and exactly how low just doesn't affect much at this point. For recreation lake levels it is all about the BoR plan.
There's at least a 10% chance that water will flow back up the Colorado from Powell!
So we can tell that "observed accumulation" is clearly NOT an input to the forecast model...
What this really illustrates is just how far out of family this year is from anything in the past. Often times models don't include inputs that seem "obvious" to us because in more "normal" times they don't actually improve the model forecasting ability. As another poster pointed out a few weeks ago this means the models can run amok when we get into weird times. Earlier in the season the climatological ensemble forecasting seemed to be very clearly biased high. Now, later in the season, we are seeing the bottom end of the ensemble resulting in a different kind of nonsense (some other folks pointed out the bottom end seemed unrealistically pessimistic a few weeks ago as well, but now it is to the point the numbers don't even add up).
Anyway, the CBRFC forecast is sort of moot at this point. The runoff is going to be extremely low and exactly how low just doesn't affect much at this point. For recreation lake levels it is all about the BoR plan.
Are you referring to the amount of water your expecting to be released from FG that is to go into to Lake Powell. Based on 1,591.000 acre feet it would increase Lake Powell by 20-25 feet. That would still be 11- 6 ft below the 2025 level as of this date and that would be if it were dropped in all at once. I don't understand also how water would run from Lake Powell up to Colorado like you wrote. What does ESP mean?
I agree we are at 59-60% through this water year. What I said was that we only released 48% of the minimum required for the water year.You’re using the wrong minimum and will need to keep up to date with reality if you are going to contribute anything useful to the thread:
JFR has been keeping up, which is why his numbers make sense and yours are wrong. We are at 60% of the release for this WY.
So what is the correct minimum required for this water year? The data base says it's 7,500,000.You’re using the wrong minimum and will need to keep up to date with reality if you are going to contribute anything useful to the thread:
JFR has been keeping up, which is why his numbers make sense and yours are wrong. We are at 60% of the release for this WY.
BoR will only release 6,000,000 af this water year as outlined in the link I provided from BoR.
This was expected for most of the spring because the drought operations in place for a number of years now have specified that BoR can drop the release that low to protect the power pool. The conditions to allow such a low release have existed since February and everyone was just waiting for BoR to officially announce that they were going to do what the drought plan says they are suppose to do. And they did exactly that in their April press release.
No, we have released 60% of the required 6 Maf for the year already. In other words, we are on pace. This is because of the reduced release for this water year. Your 48% is based on the incorrect number for this water year (which has been the "correct" number for the past few years and probably why the volunteer run database is wrong).
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The CBRFC forecast models "unregulated" flow, meaning it ignores dam operations and thus does not include the FG release. It is just how much runoff is available to the entire basin. Which reservoirs it ends up in at what time depends on what BoR does. So it doesn't actually directly tell you what ends up in Lake Powell. Even if the forecast was exactly correct you might get less in Powell because more was held in upstream reservoirs, or you might get more because there were larger releases from upstream reservoirs (like this year with the big FG release).
The water "running up the Colorado" is just a silly joke. The bottom end of the forecast range is that the upper basin (indirectly Lake Powell) will receive less water from April through July than has already happened! (Note the ESP 90 number compared with the Observed Accumulation number). That's of course impossible unless the river were to "run backwards" as the joke says. As mentioned in the post, this is because the year is so weird it is breaking the CBRFC ESP model itself. The ESP model doesn't actually use observed flow as an input, so it can come to the ridiculous conclusion that the forecast total runoff is less than the already observed runoff! Big forecasting error, but only "big" in the sense that it is an impossible outcome. The actual amount of water in the error isn't that big compared with typical errors, but the run off is just so low this year even a "smallish" error can result in a nonsense forecast output.
ESP stands for Ensemble Streamflow Prediction which is the model the CBRFC uses for predicting runoff. "Ensemble" means that it uses the statistics of past runoffs combined with various current measurements to make a forecast for the present year. The problem with such a model is that when the current year is way outside the "ensemble" of past years the modeling doesn't work very well.
You can see the forecast here:
There are some links in the various pull downs that give some explanation to the model, links to monthly briefings about the model outputs, and controls to change forecast parameters and what the graph displays. Again, this year it isn't a great forecast, but it is really the "best" tool available to water planners for the Colorado Basin.