Spring Runoff Reality Check - May 7

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Outside said:
View attachment 28234View attachment 28234
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If we play out the implications of @Outside's chart of inflows from Cataract Canyon through June 20, assume that San Juan inflows remain in the 2,000 cfs range, and that outflows from Lake Powell are as planned by USBR (about 10,600 cfs on average each day in June), here's what the next 10 days look like on Lake Powell:

1. The lake reaches 3582.6 on June 20.

2. The peak rise happens June 11-13, about 0.90 feet per day.

3. The daily rise slows down after that, and is back in the vicinity of 0.5 feet per day by June 20.

4. After June 20, the daily rise is likely to drop quickly. Extrapolating out the graph, we'll be back down to 3 inches a day by June 23 or so.

5. The lake likely hits 3583 on June 22 or so.

6. If we're lucky, the lake crawls up to about 3585 the first few days of July, then plateaus about there...

That's the best guess for now....
 
jimmybame said:
water database shows inflows dropped by more than half yesterday 😳
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The inflow number is basically a guess since they don't have a good way to determine that exact number. Accordingly, they make an adjustment that satisfies the equation ; New Lake Level = Old Lake Level + inflow - outflow. Minor adjustments for bank storage, bank release and evaporation are also needed.
 
JFRCalifornia said:
That sounds right. That means the lake rose 0.90 feet yesterday, and inflow was around 45,000 cfs. That's about what we should have expected... My guess is that on the Water Database, it will "overcorrect" tomorrow...
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I think I jinxed it. Yesterday on my Facebook page, I posted some basic facts on the cut how we're up to 8"+ a day now, and less than 8 feet from the Cut opening. Then promptly the numbers (incorrectly) were chopped in half on the site :ROFLMAO:
 
RobertGosselin said:
The inflow number is basically a guess since they don't have a good way to determine that exact number. Accordingly, they make an adjustment that satisfies the equation ; New Lake Level = Old Lake Level + inflow - outflow. Minor adjustments for bank storage, bank release and evaporation are also needed.
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And sometimes it's just a mistaken number and is corrected the next day as this one was.😉
 
So what is the lake at today is it 3577.12? Or was that a mistake I’m hoping it was not a mistake! If it was a mistake it will be corrected or should I say over corrected tomorrow?
 
Jon.Diedrich said:
So what is the lake at today is it 3577.12? Or was that a mistake I’m hoping it was not a mistake! If it was a mistake it will be corrected or should I say over corrected tomorrow?
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I would say 3577.12 is accurate. In the last two days, the lake rose 1.82 feet. It should have been shown as about 0.91 feet each day, but instead the "correction" of 1.57 feet was added to the inaccurate 0.25 feet reported from the day before to make up for the shortfall. We're back on track now.
 
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