Question on Outflow

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jasonjsimon

jasonjsimon

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According to the LP Database, Today is day 228 of 365 for the Water Year 2019. We are 62% through the Water Year.
And, Total releases for water year 2019: 5,416,516 acre feet. This is 72.22% of the minimum required of 7,500,000 acre feet.

So, we are 62% through the water year, but have already released 72% of the minimum outflow. Does this mean that at a certain point, the outflow will be reduced down below the average outflow, or will we continue to release and go well beyond the minimum outflow? Data seems to tell me that we are releasing more than we need to. I know this is very complicated stuff, but am I missing something or oversimplifying?
4931
 
Well, as you might suspect, it's more complicated than the LP Database indicates. Under the current protocol followed by the Bureau of Reclamation, the minimum release requirement is 8.23 MAF, not 7.5 MAF. The "extra" accounts for the Upper Basin's share that goes to Mexico's allocation of the Colorado River. The Bureau can release up to 9.0 MAF (but not more) in order to achieve a better operational balance between Mead and Powell, and right now, since Lake Mead is in more critical shape than Powell, they plan on releasing 9.0 MAF from Powell in Water Year 2019. That means the LP Database is misleading/wrong. Instead of saying we are at "72% of the minimum required 7.5 MAF", it should really say we are at "66% of the minimum required 8.23 MAF", or more accurately, we are at "60% of the projected release of 9.0 MAF expected in the current Water Year".

That being the case, since we are at 60% of projected releases for the year, but 62% of the water year has gone by, we are going to see similar if not slightly higher average releases through the end of the water year, which is September 30. Doing the math, in order to get to 9.0 MAF by the end of September, there would need to be a total release of about 3.6 MAF over the next 130 days, which is an average of about 27,500 AF/day, which is the same as roughly 13,800 cfs every day. Right now the average releases are on the order of 12,000 cfs, so I'd expect this to actually tick up a notch, especially as inflows really start picking up at the end of May and into June...
 
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I don't know a lot of the stats and details, but common sense tells me the authorities want to balance the water level between Powell and Mead. I don't know ratios and relationship between the two, but with run-off projections running high I would assume many are looking to replenish Mead a good amount if possible... so yeah, I would expect some increased outflow from Powell.
 
JFRCalifornia said:
Well, as you might suspect, it's more complicated than the LP Database indicates. Under the current protocol followed by the Bureau of Reclamation, the minimum release requirement is 8.23 MAF, not 7.5 MAF. The "extra" accounts for the Upper Basin's share that goes to Mexico's allocation of the Colorado River. The Bureau can release up to 9.0 MAF (but not more) in order to achieve a better operational balance between Mead and Powell, and right now, since Lake Mead is in more critical shape than Powell, they plan on releasing 9.0 MAF from Powell in Water Year 2019. That means the LP Database is misleading/wrong. Instead of saying we are at "72% of the minimum required 7.5 MAF", it should really say we are at "66% of the minimum required 8.23 MAF", or more accurately, we are at "60% of the projected release of 9.0 MAF expected in the current Water Year".

That being the case, since we are at 60% of projected releases for the year, but 62% of the water year has gone by, we are going to see similar if not slightly higher average releases through the end of the water year, which is September 30. Doing the math, in order to get to 9.0 MAF by the end of September, there would need to be a total release of about 3.6 MAF over the next 130 days, which is an average of about 27,500 AF/day, which is the same as roughly 13,800 cfs every day. Right now the average releases are on the order of 12,000 cfs, so I'd expect this to actually tick up a notch, especially as inflows really start picking up at the end of May and into June...
Click to expand...
As always, thanks for sharing your analysis and thorough understanding of how this all works. It's pretty interesting stuff. Not sure who is responsible for setting the projections on the DB site, but might be good to update the statement so it is based on projected release.
As a side note, I did notice today that the Database page was updated for the Bullfrog ramp - the minimum level was raised. Does anyone know if this was because of the coffer dam that was left intact?
 
How does the new water law just passed this spring effect this. My understanding was Powell would become the priority water storage.
 
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