How low will it go?

flowerbug

Active Member
i'm in love with Mono Lake and what they've managed to do to come up with a plan to get LA water to scale back during the dry times so they can gradually replenish the lake level. it is gradually going up and if they can get a couple more wet years that will set the stage for them to get back to where both LA and Mono Lake community gets what they want. a functioning ecosystem and a supply of fresh water.
 

JFRCalifornia

Well-Known Member
i'm in love with Mono Lake and what they've managed to do to come up with a plan to get LA water to scale back during the dry times so they can gradually replenish the lake level. it is gradually going up and if they can get a couple more wet years that will set the stage for them to get back to where both LA and Mono Lake community gets what they want. a functioning ecosystem and a supply of fresh water.
Yes, Mono Lake these days is a success story, and the product of a win-win settlement between LA and environmental groups... and the increased flow along the Owens River has kept the dust down from Owens Lake too...

Apart from Lake Powell, the eastern Sierra from Lone Pine up to Bridgeport is my favorite place to be.... The irony of the LA Aqueduct in the Owens Valley is that because LA bought a lot of the land there decades ago, and diverted water southward to LA instead of its former use to irrigate ag fields in the Owens Valley as was the case in 1900 or so, the valley has remained largely undeveloped, and returned to its historic desert state as it was in the days before agriculture... without that, I’d imagine those valley towns like Bishop and Lone Pine would have grown quite a bit... The big loss of course of LA’s scheme was the annual spring flood of the Owens River that once created a lot of the riparian/wetland habitat near the river... now long gone on a large scale, but there are still some nice remnants...
 

PBR

Active Member
No one has mentioned the reservoir levels above Powell, they are all substantially higher then they were last year at this time. I would guess that the inflow to Powell will be higher than expected even if we only have an average snow year. Flaming Gorge 3' higher than it was last year, Blue Mesa 51' higher and Navajo 41' higher. I know this is only a drop in the bucket but all of those reservoirs where in horrible shape last year and there was enough water to bring them way up and still put 50+ into Powell.
 

flowerbug

Active Member
No one has mentioned the reservoir levels above Powell, they are all substantially higher then they were last year at this time. I would guess that the inflow to Powell will be higher than expected even if we only have an average snow year. Flaming Gorge 3' higher than it was last year, Blue Mesa 51' higher and Navajo 41' higher. I know this is only a drop in the bucket but all of those reservoirs where in horrible shape last year and there was enough water to bring them way up and still put 50+ into Powell.
i've seen the level reported on the data website vary quite a bit the past few days/week or so. sometimes i see the total around 80-82% and other times up to 85% or so. i just checked and it is saying 80.46% the river flow numbers also seem to be bouncing around some.

otherwise yes, i agree with you, like CA, CO is in a much better spot this year than it was the year before.
 

JFRCalifornia

Well-Known Member
No one has mentioned the reservoir levels above Powell, they are all substantially higher then they were last year at this time. I would guess that the inflow to Powell will be higher than expected even if we only have an average snow year. Flaming Gorge 3' higher than it was last year, Blue Mesa 51' higher and Navajo 41' higher. I know this is only a drop in the bucket but all of those reservoirs where in horrible shape last year and there was enough water to bring them way up and still put 50+ into Powell.
Thats a good point about the reservoirs above Powell. That said, I'm not sure how much of a difference they will really make. The fact is that the entire capacity of those reservoirs isn't huge. The six main reservoirs--Flaming Gorge, Blue Mesa, Navajo, Morrow Point and Crystal--have a combined capacity of only about 6.5 MAF, or roughly a fourth of the total capacity of Lake Powell. It's also notable that on June 6, 2019--in the midst of the huge rise on Powell--those reservoirs were already at a collective 81% of full capacity, or 5.2 MAF. So I think the fact is there wasn't too much water that could be held back at that time.

And here's the thing: the current reservoir volume in those 6 reservoirs as of 1-7-20 is 5.3 MAF--almost identical to what they were holding in June of last year. Yes, they will likely fill even more as snowpack melts, but it's not enough to make a huge difference in Powell, if any. There's going to be some release from them even as they fill, just as there was last year. But the more important consideration is simply that USBR is going to have to release at least 8.23 MAF past Lees Ferry just as a matter of the Law of the River...last year they released 9 MAF, which was also following protocols based on relative lake levels in Mead and Powell, so the contributions of the upper reservoirs won't make a ton of difference if the release through the dam is big...

The eye-opening story is this: even with the huge runoff of spring 2019, the collective peak storage of Powell and Mead that year was only 49%, or 24.8 MAF, or only about 3% more than in 2018. And the average capacity for the year was actually less than the average of 2018--mainly because the first 3 months of 2019 were actually terrible. In 2019, the average collective capacity was at 44%, compared to 44.6% in 2018. In fact, the two reservoirs collectively have hovered in the 45-50% range pretty steadily since 2013 after the sharp drought of 2012-13. That is, it doesn't take a long drought to drop the levels, but it takes a long recovery to start bringing them back (unless you get two straight monster years like 1983-84, which has happened exactly once). In a nutshell, that's because the demand on water from the Colorado River basis, on average, far exceeds supply via precipitation. The only way out of that one is to renegotiate the shares of each of the 7 basin states, because as it is, what they are entitled to collectively is way more than what is actually there on a sustainable basis. No other way around that one...

But I'm optimistic that in the coming years there will be variability in the lake levels, up and down. Hopefully, this winter is huge, and it's promising that the snowpack is already good with some pretty full reservoirs above Powell. Let's hope for the best. In that context, you might ask why didn't we have any trouble getting the lakes to full capacity by 1980, and what has changed since then? Well, we did have trouble--it took 17 years to do that as Powell was filling, and in 1963, Mead was about 80% full already. Some big years were offset by a lot of pretty bad ones in the late 1960s and especially in the mid-1970s. But some truly giant years in there--1973 and 1979 come to mind--brought Powell to the top, and some unprecedented and never-seen-again years from 1983-86 made everyone believe that should be normal and would last forever. But those were abnormally huge runoff years, and we'll never likely see that kind of run again in our lifetimes...nor had we seen any run of years like that in the recorded data before Powell began to fill in 1963... Still, from the full pool period of 1983-87, we only dipped to a collective 75% in 1993 before slowly working back to near full in 1998-99. That's because we didn't have a truly catastrophic drought in that time. But all it took was a huge drought from 2000-04, only five years, to reduce the volume of those two reservoirs from basically full to 50%. It inched up to nearly 57% by 2012 after a few better years, but then all it took was those two bad years in 2012-13 to drop us back to closer to 45%. So you can see the trend line--short sharp drops followed by slow recoveries... that will continue... hopefully this is another year toward slow recovery...
 

flowerbug

Active Member
Thats a good point about the reservoirs above Powell. That said, I'm not sure how much of a difference they will really make. The fact is that the entire capacity of those reservoirs isn't huge. The six main reservoirs--Flaming Gorge, Blue Mesa, Navajo, Morrow Point and Crystal--have a combined capacity of only about 6.5 MAF, or roughly a fourth of the total capacity of Lake Powell. It's also notable that on June 6, 2019--in the midst of the huge rise on Powell--those reservoirs were already at a collective 81% of full capacity, or 5.2 MAF. So I think the fact is there wasn't too much water that could be held back at that time.
...
it shall be interesting! plus i'm going to be excited to finally be able to take part in the water level guessing contest after watching everyone else take the kerplunks i get to put my neck on the line!


from the inkstain website this was a quote from an item from a few days ago regarding CA's use of CO river water:

"Its use of Colorado River water in 2019 will be 3.858 million acre feet. The last time it was below 4 million acre feet was 1950, as the state’s big diversions – the All-American Canal and the Colorado River Aqueduct – were ramping up."
 

JFRCalifornia

Well-Known Member
it shall be interesting! i'm going to be excited to finally be able to take part in the water level guessing contest after watching everyone else take the kerplunks i get to put my neck on the line!


from the inkstain website this was a quote from an item from a few days ago regarding CA's use of CO river water:

"Its use of Colorado River water in 2019 will be 3.858 million acre feet. The last time it was below 4 million acre feet was 1950, as the state’s big diversions – the All-American Canal and the Colorado River Aqueduct – were ramping up."
That's very interesting, good news, and a big step in the right direction, considering that CA's entitlement is for 4.4 MAF annually... so that's almost 15% less than what they theoretically could take...

CA actually does a lot of good things in the water world, in spite of the reputation. On the demand side, they have water conservation baked into most local plans, drought-tolerant landscaping is generally required, low flow plumbing, etc. And per capita use is way way down over the past 30 years. Some cities will even pay you to get rid of your grass lawns, and replace them with native drought-tolerant plants which look better than grass anyway. For ag fields, there's an emphasis on less irrigated ag crops (away from things such as almonds, lettuce, etc.), plus better irrigation practices that minimize runoff and evaporation. Then on the supply side, there's a big effort to do even radical solutions, like "toilet-to-tap" recycled water plants, which essentially means drinking treated wastewater...I've had it, it tastes fine... and then of course desalination plants...
 

JFRCalifornia

Well-Known Member
In general, when the lake is anywhere from 3610-3650, the rule of thumb is 10 feet of rise for every 1 million acre feet of added volume. So if the lake is at 3615 and you add 0.5 MAF, you end up at 3620. If you started at 3615 and added 1.0 MAF, you end up at 3625.
 

flowerbug

Active Member
In general, when the lake is anywhere from 3610-3650, the rule of thumb is 10 feet of rise for every 1 million acre feet of added volume. So if the lake is at 3615 and you add 0.5 MAF, you end up at 3620. If you started at 3615 and added 1.0 MAF, you end up at 3625.
interesting! for some reason i didn't think it would be that much. thanks! i'll keep hoping for more snow soon! a nice gradual series of repeated storms and another long slow melt like last season would be pretty nice...
 

KYKevin

Well-Known Member
I'm kinda like the glass of water being half full, or half empty. I would rather ask the question, how full will it get (y), with mother nature you never know, there will be another 1983, when history repeat's itself. I hope I'm still fishing, it will be awesome.
 

JFRCalifornia

Well-Known Member
And another nice way to track the rise of the lake is to track the net inflow. It takes a total of 500,000 cfs of net inflow to produce a volume of 1 MAF. So if you think of the spring as the main opportunity for lake rise, and you assume that's roughly the months of April through June, maybe a few days into July, that's about 100 days of rise. (In fact the measured average period of springtime rise since 1965 is 100.2 days, but it's got a huge degree of variability...) So that means if you average 5,000 cfs more inflow each day than outflow over those 100 days, you get 500,000 cfs total, or 1 million acre feet.

What all that means is if you are shooting for a 50 foot rise (like last year), and assume you've got a 100 days to do it, you think in these terms:

50 foot rise = 5 MAF net volume increase = 2,500,000 cfs = 25,000 cfs net inflow each day for 100 days. So just track inflow minus outflow every day on the LP water database, and you've got good idea how things are progressing...

By the way, in 2019, the "rise" period was 115 days...
 

JFRCalifornia

Well-Known Member
Very interesting story...and ironic how rising lake levels in Mead are costing somebody money--well, are at least causing one small marina to have to move its operations a bit. Mead has risen about 9 feet since Halloween, and really that can be mostly attributed to one thing--the recent voluntary cutbacks in use from CA, AZ, and Mexico. But it's got a long way to go--Mead is still about 130 feet below full.

In terms of what factors affect lake levels in Mead and Powell, it's pretty simple, and those factors are different. The big difference between the two lakes is this:

Powell's lake levels depend almost entirely on inflow, and that means precipitation/snowpack runoff in the upper Colorado River basin. On the other hand, Mead's levels depend almost entirely on outflow, and that means water use in the lower basin states and Mexico. Other influences on the system are way less important.

The key in all this is that outflow from Powell (i.e., inflow to Mead) is largely fixed and regulated by the USBR, and it generally ranges between 8.23-9 MAF. This means that inflow to Mead is almost always the same from year to year, as is outflow from Powell. It also means that the math doesn't really work for sustaining Mead in the long run, unless we change things up a bit. The theoretical water rights of the Lower Basin states and Mexico are a collective 8.5 MAF (7.5 to CA, AZ, and NV; 1.0 to Mexico). In addition, there is significant water loss through evaporation and vegetation along the way using the water. So the typical releases from Powell are not really enough to cover all that, and inflow from Mead's other sources (Virgin River, Muddy River and Las Vegas Wash) doesn't amount to a whole lot. Hence, the need for the lower basin states and Mexico to cut back--which they are now doing under a recent agreement--and it's apparently working. Good news.

As an aside, if the St. George pipeline ever happens (and I think it's a really bad idea, for several reasons I won't get into here), what that is going to do is transfer water out of Powell into the Virgin River basin--essentially an interbasin transfer. And since the Virgin River flows directly into Mead, any return flow will have the tendency to raise Mead a bit, while Powell will be lowered by the direct diversion to St. George.

For Powell, these actions would mean USBR would one day likely have to modify its Glen Canyon Dam release protocols, but don't look for that happening anytime soon until Mead is out of the woods and the pipeline issue is resolved. Until then, we're counting on heavy sustained snowpack in the upper basin, and avoiding drought...
 

flowerbug

Active Member
I was about to make this very point. Upstream reservoirs are in much better condition this winter.
i think the underlying hydrology is also better. that pulse of water in the system from last year may take years to fully go through the ground. at least as far as i know not all water that hits the surface comes off immediately. i'm sure the water people have some ideas of how that works by now, but there is still much worth learning to be found out too. :) i wish i had a few lifetimes to do it.

the technology is changing quickly. some time ago we had no real idea of how to measure groundwater changes. now they can measure some of this from space. it's really going to be interesting to watch how this continues to play out.
 

flowerbug

Active Member
i was looking at the two year chart for the river flows as reported by the data site. even though this summer was pretty dry the river flows did not go down nearly as much compared to the very dry spell of the year before. as of now the river has been running above the average flows so i consider this a continued good sign of the season to come. *doing the rain/snow dance* :)
 

Dorado

Well-Known Member
The biggest reservoir above, Flaming Gorge, has been pretty full for a while (the Upper Green has been wetter, 2018 water year was actually above average, compared to the miserable snowpack in the rest of the Colorado River Drainage). So releases last year weren't that different. That being said, Blue Mesa was super low, along with the other Colorado and San Juan Reservoirs. Their refilling definitely caused some to the delay in inflow to LP last year. Plus, as noted above, the soil moisture and groundwater were very low going in to winter last year. One can hope more water will end up in the river if we keep the good snowpack through the winter.

Lets just hope the storm cycle continues through March, it looks like high pressure is going to put a pause on the storm systems bringing all the snow...the worst thing would be a prolonged high pressure blocking moisture during the prime snow months!!!
 

flowerbug

Active Member
looking at the snow pack graph i see the recent pop from the storms has put the level at where two of the past five years levels maxed out at. with months to go, things are shaping up nicely.
 
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Rivergoer

Well-Known Member
OK water nerds, down in AZ and So Cal we’ve seemingly hit a dry patch weather-wise for the past month or so...how’s the Upper Basin doing and any revisions to the forecast low? (will the Cut remain open still?)...Thanks!
 
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