The 2022 Runoff Graphed

SDuncan

Active Member
The graph is the total of the three major tributaries to the Lake. (Colorado, Green and San Juan Rivers)
Graph shows average flow in cfs, the 2022 flow in cfs, and the 2022 flow as a percent of the average.
I'll try to post this every Monday. All data is from the USGS

USGS 06-27.JPG
 
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Dougie

Well-Known Member
Nice work. Great visual representation. Lake level actually declined again Sunday. No major heat waves in the forecast to kick up the runoff. No major late-winter storms to add water to our soils and high-mountain snowpack. Lucky we have the 2 stopgap measures in place--less going down the drain to Mead, and more inflow from Flaming Gorge.
 

sparkin5280

Well-Known Member
I hope it happens soon too and in abig way. I will say that today is Tuesday May 3rd I've been camping on the lake since Sunday. I've been monitoring the lake level closely not much change but from the end of yesterday until the end of today it seems like it's come up 2 or 3 in. I think the rise is actually starting to happen...
 

Dom Tomac

Member
Nice visual of what is happening & how the '22 runoff will affect the lake level. Unfortunately, it doesn't look too good.
 

Gunny

Active Member
Over one third of the snowpack is already gone and the lake has risen but a couple of inches in over two weeks. So where in the hell did it all go?
 

Colorado Expat

Well-Known Member
The fact that a moderate chunk of the Upper Basin snowpack has already melted but the rivers have not shown a major hydrological response has been puzzling to me as well. There could be several reasons for this, all of which might be additive:

1) Unseasonably warm temperatures in March and April, coupled with some high wind events could have created an atmosphere with a high vapor pressure deficit and evaporative demand, so that some of the snowpack simply sublimated and got taken up by the air. A recent NOAA study looking at the ongoing Southwest drought warned about this phenomenon. See the following reference, available online, which makes sobering reading:
Mankin, J. S., Simpson, I., Hoell, A., Fu, R., Lisonbee, J., Sheffield, A. & Barrie, D. 2021. NOAA Drought Task Force Report on the 2020–2021
Southwestern U.S. Drought.
NOAA Drought Task Force, MAPP, and NIDIS.

2) Because we carried a soil moisture deficit over from last year’s very dry November of 2021, and because quite a bit of the Upper Basin vegetation was drought stressed when it went dormant at the start of the cold winter season, there may have been a fair bit of latent moisture demand in the forests and shrublands, which immediately utilized melting snowpack when it became available. From what I recall in USDA briefs from a few months ago, the soil moisture deficit, although not as bad as we had coming out of the winter of 2020-2021, was still going to be enough to reduce potential runoff by 15 percent. And that was just to replenish water in the soil pore spaces, and did not figure in additional demand from stressed vegetation.

3) Trans-basin diversions in the river headwaters, particularly in Colorado, almost certainly pulled off a moderate bit of the initial runoff before it ever got to points where it could be gauged. Even so, Denver’s water supply reservoirs are hardly brimming and topped up. At its quarterly board meeting on April 20, leaders of the Colorado River District met to discuss current matters regarding the state’s river waters. In an update to the board, Director of Science and Interstate Matters Dave Kanzer and Senior Water Engineer Don Meyer reported that the reservoirs across Colorado are very unlikely to fill before the summer. As of late April, Denver Water reported that Dillon Reservoir, their primary Western Slope storage facility, was only 78% full.

This group’s report also noted that, much along the lines of my reasoning above: “Lower-than-normal snowpack across the West continues to be exacerbated by dry soil conditions and ‘thirsty’ atmospheric conditions. This is expected to continue to cause the larger-than-normal demand for water that has adversely impacted reservoir storage across the Upper Colorado River Basin, and the prospect for refilling them is not optimistic. In other words, the significant cumulative hydrological deficit continues to grow; it will take multiple years of above average conditions to recover.”

In sum, there appear to be multiple factors that are decoupling the relationship between snowpack melt rate and river flows this year. At the moment, the cumulative flow hydrograph for the Colorado River at the Cisco gauge, near the Utah line, is tracking the pattern from the very dry year of 2002, which was the lowest ever recorded. If that continues, it is going to be a bleak runoff year indeed, and my sense is that BOR already realizes this, thus their recent emergency measures to stabilize a system that is in far worse shape than they thought it would be even two months ago. This is all just the cumulative result of a 20-year drought that with each passing year is trending more toward a pattern of long-term regional aridification, and until this climate pattern changes, the entire region is going to have major water issues that will impact all users up and down the Colorado River system. The question is not going to be whether we can fill Lake Powell, but whether we can fill any of the major reservoirs, and if so, which ones and why.
 

flowerbug

Well-Known Member
having accurate measurements is pretty tough when your instruments are not comprehensive. i was just nosing around the news and came across this article:



this article has some interesting pictures from satelites:

 
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ndscott50

Active Member
A major factor this year is the amount of water being held back in upstream reservoirs. While this is always a factor, I think downstream releases are less than normal at many due to low water levels. Blue Mesa is a good example, that average release for this date looks to be around 1150cfs. The average for the last two weeks is 600cfs. I took a quick look at the large and mid-size reservoirs with no reservoir below them and Powell. The net difference between inflow and outflow is currently 8,000cfs. This number is low as there are several smaller ones I did not look at as well as all the reservoirs above these also adding more water than they release. Ballpark maybe 10,000cfs net storage underway upstream of Powell. Not sure what this would be in a "normal" year. It seems like that data should exist somewhere.
 

Dougie

Well-Known Member
Warm and windy across most of the headwaters with a sharp and mostly dry cold front cutting the state in half about I-70. Extended 10 day forecast shows little precip and mostly above normal temps. By the 20th of this month we will have melted 2/3 of the snow water equivalent. If we are going to see 30,000 CFS on any single day into the lake this runoff season, it better happen soon. Snowpack is going down fast, and river flows are dawdling way behind. I’m starting to think we may have a worse runoff than even the recent projections are forecasting. I thinks most of it will be over by the end of the month.
 

drewsxmi

Escalante-Class Member
Warm and windy across most of the headwaters with a sharp and mostly dry cold front cutting the state in half about I-70. Extended 10 day forecast shows little precip and mostly above normal temps. By the 20th of this month we will have melted 2/3 of the snow water equivalent. If we are going to see 30,000 CFS on any single day into the lake this runoff season, it better happen soon. Snowpack is going down fast, and river flows are dawdling way behind. I’m starting to think we may have a worse runoff than even the recent projections are forecasting. I thinks most of it will be over by the end of the month.
I recall the spring of 2021 being warm, dry, and windy. Along the Wasatch Front this year it "feels" cold, wet, and windy, but I see the severe weather alerts for northern Arizona, New Mexico, and southern Colorado, and it sounds like the weather for the Colorado River Basin is closer to the warm, dry, and windy pattern. Last year the USBoR seemed quite surprised by how low the runoff was, and gave the low soil moisture as the explanation (if I recall correctly). This year the snowpack appears to be better, and we had the monsoon rains in the summer, so the soil moisture levels should be higher. If we get really low runoff again this year, I think the forecasters will need to figure out how to quantify the "warm, dry, and windy" conditions as part of the ongoing forecast.
 

Dougie

Well-Known Member
Humidity under 20% for 72 hours straight in Page and Grand Junction with strong warm southwest winds. Clear up at Aspen airport many such hours too, although some overnight recovery as wind speeds lower and then pick up by noon. This has got to be evaporating a ton of snow from the top down, sending moisture up into thin air, not trickling down into soils. These dry and windy conditions are forecasted for 72 additional hours. River flows up to 15K CFS this Monday morning, but snowpack water storage is now less than 50% of the high we reached this spring, so like it or not, we are very near the peak of the 2022 spring runoff, a month early and at half the river volume we should be seeing. I’m afraid that after this week, no matter how hot it wants to get, there simply won’t be the snowpack left to melt fast enough to produce a 30,000 CFS day.
 

Dom Tomac

Member
If the BOR is having difficulty explaining low runoff levels, perhaps they need to "dig" into the effects of deep wells and the depleted aquifer? With a ground water depleted, any surface moisture just keeps getting drawn deeper into the ground. Even flowing river beds my be loosing allot of water to vertical absorption that never becomes saturated due to a now dry aquifer?
 

SDuncan

Active Member
OK, here's the updated graph. I updated the graph in the opening post as well. The USGS data is marked "Provisional data subject to revision" and when I checked the numbers this morning, the previous numbers for the Colorado had been revised down 20 CFS, with a couple of days going down 30 CFS. Small potatoes in the grand scheme of things. No adjustments appeared for the Green or San Juan rivers.
USGS.jpg
 

Dorado

Escalante-Class Member
Warm and windy across most of the headwaters with a sharp and mostly dry cold front cutting the state in half about I-70. Extended 10 day forecast shows little precip and mostly above normal temps. By the 20th of this month we will have melted 2/3 of the snow water equivalent. If we are going to see 30,000 CFS on any single day into the lake this runoff season, it better happen soon. Snowpack is going down fast, and river flows are dawdling way behind. I’m starting to think we may have a worse runoff than even the recent projections are forecasting. I thinks most of it will be over by the end of the month.
That is definitely not the case further north…Cold, wet and windy in the green river headwaters, the snowpack as a percentage of average keeps going up. But I agree that runoff is still going be pretty paltry whenever it does happen. We are just fortunate that the we are getting the edge of the moisture that has been pouring through the Pacific Northwest. Not a ton of precipitation, but at least it is keeping things wet and delaying runoff. Most of the big lakes around Pinedale are still frozen or just starting to thaw. Looks like it is nothing but a warm dry wind as you go south….
 

Dougie

Well-Known Member
And even farther south and west I got 1 inch snow at my house last night along with a nice wetting rain in Provo. But our Wasatch snowpack is 60% of normal, so this little storm did nothing substantive for our Great Salt Lake which is hitting all-time lows and exposing wide areas of salt beds and noxious minerals that the wind picks up and delivers as mud rain. Also, if you look, the headwaters of the Green are below 100% of normal snowpack. So it may “feel” cool and windy and wet, but the facts on the ground show otherwise.
 

Dorado

Escalante-Class Member
And even farther south and west I got 1 inch snow at my house last night along with a nice wetting rain in Provo. But our Wasatch snowpack is 60% of normal, so this little storm did nothing substantive for our Great Salt Lake which is hitting all-time lows and exposing wide areas of salt beds and noxious minerals that the wind picks up and delivers as mud rain. Also, if you look, the headwaters of the Green are below 100% of normal snowpack. So it may “feel” cool and windy and wet, but the facts on the ground show otherwise.
Yes, but it was at 68% back in March! To clarify, that is the Upper Green Snotel for Wyoming, not the overall upper Green in the Colorado River basin table. It is 28 degrees and snowing right now, so it doesn't just feel cool! But yeah, it is not looking good for water, there is no way around that....
 
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Colorado Expat

Well-Known Member
I recall the spring of 2021 being warm, dry, and windy. Along the Wasatch Front this year it "feels" cold, wet, and windy, but I see the severe weather alerts for northern Arizona, New Mexico, and southern Colorado, and it sounds like the weather for the Colorado River Basin is closer to the warm, dry, and windy pattern. Last year the USBoR seemed quite surprised by how low the runoff was, and gave the low soil moisture as the explanation (if I recall correctly). This year the snowpack appears to be better, and we had the monsoon rains in the summer, so the soil moisture levels should be higher. If we get really low runoff again this year, I think the forecasters will need to figure out how to quantify the "warm, dry, and windy" conditions as part of the ongoing forecast.
Snowpack losses due to “warm, dry, windy” conditions relate back to technical concepts like increasing vapor pressure deficit and associated evaporative demand, but it all comes down to the fact that a warmer atmosphere holds more water. Mean temperatures across the Colorado Rockies ran above normal all winter long, within the top 33 percent of long-term averages. This does not mean it was 80 degrees in the middle of winter, but it does mean that throughout that period the atmosphere was pulling more water out of the land and the snowpack than would otherwise have been the case. In the long run, this all adds up, and we now seem to be seeing the aggregate results of that steady atmospheric demand. This is a problem that may stay with us going forward, and as you note, forecasters will need to do a better job of integrating it into their runoff models.

The snowpack losses since the end of March have also shown a marked north to south gradient, based once again on temperature patterns. The persistent La Nina pattern kept the storm track and cooler weather consistently north through April and now into May, so that as of today in Colorado the remaining snowpack as percent of normal for this date, across major river basins (from northernmost to southernmost) is:

Yampa & White: 87%

Upper Colorado: 82%

Gunnison: 64%

San Miguel, Dolores, Animas & San Juan: 26 %

So at this point, runoff from the San Juan Mountains, normally a snow factory, is basically over, and will be soon in the Gunnison Basin as well. So 30K cfs is looking further out of reach with each passing day, and even if we do hit that number it will only be for a short period of time.
 

upthecreek

Active Member
Looking at the release numbers from the upstream lakes will show where most of the runoff is winding up. Mcfee average outflow for this day since filled is 740 cfs, They are releasing 7cfs daily now. Navajo average is 1600 cfs, 300 cfs now and it goes on for the others as well.
 

Colorado Expat

Well-Known Member
Looking at the release numbers from the upstream lakes will show where most of the runoff is winding up. Mcfee average outflow for this day since filled is 740 cfs, They are releasing 7cfs daily now. Navajo average is 1600 cfs, 300 cfs now and it goes on for the others as well.
And even with that, those reservoirs are still at rock bottom. Blue Mesa and Navajo are below their 10th percentiles of long-term average storage volume, and McPhee just managed to creep into the 10th percentile range this week. In addition to those three, there are many smaller reservoirs run by local ditch companies whose water rights pre-date the Compact, and no doubt they are taking a share as well. It all ends up being pretty slim pickings by the time the remaining flows get to Hite.
 
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