Snow pack drainages

#1
Looking at this map:
https://www.usbr.gov/UC_SnowMap/

I am very pumped to see the high snow pack totals right now, but it got me thinking. Which of these drainages are the most important? Which ones produce the most runoff for Lake Powell? I'm too lazy to look up the exact numbers, but I know some of those drainages don't contribute much to the total amount of water for Lake Powell. For example, the snow pack in Southeastern Utah is a small fraction of the water that the snow pack from the Upper Colorado. Does anyone have some numbers to show in order from most water contribution to least from the drainages that contribute to Lake Powell? The impetus for this question was seeing that the Yampa/White drainage was the lowest and only at 121% right now.
 

Chet Garling

Well-Known Member
#2
my guess would be the Colorado river provides the most inflow even from way up the drainage. The White and Yampa are much smaller rivers.
 

Gem Morris

Well-Known Member
#3
It's unconventional for the bigger of 2 rivers above a confluence to NOT have the name of the river below the confluence. Does that make sense? Couldn't figure out how to word that more clearly.

But that is exactly what happened in the case of the "Colorado" River and the Green River. Above the confluence of these 2 rivers, the smaller river (currently named "Colorado") was named the "Grand River". This is where "Grand" Junction comes from and "Grand" Mesa - because the river that runs past them used to be named "Grand". A delegation of Colorado politicians didn't like the thought of the Colorado River running through Utah so they lobbied the powers that were and got the Grand River name changed to Colorado.

That's a long story to a short question.

And honestly I don't know if the Green contributes more to Lake Powell or the Colorado. But I do know that the Green River is longer than the Colorado River. I guess that's what I meant by "bigger" above. Not actually "bigger", but certainly longer.
 

JBinNM

Well-Known Member
#4
I remember reading somewhere that the name was changed because there was already a Rio Grande. But don't trust my memory. Now I need to know!
 

Dale

Well-Known Member
#5
WB probably has the answer. My guess is the Green is the biggest contributor, but it could vary, depending on where the storms hit. Unrelated: My brother in N Idaho had his 100th consecutive day of snowfall yesterday! I left that in 1974!
 

Dave I.

Well-Known Member
#6
Right now the Green river is putting more water into the lake than any other but over all, the Colorado is the biggest drainage into Powell.
Right now the Green is putting in 6760 CFS and the Colorado is putting in 4040 CFS but the normal averages are pretty close to each other.
Since Colorado has a much later spring than southern Utah, those number will change starting next month and the Colorado will definitely start to flow more.
It has been a GREAT snow year so far so it will be interesting to see how much flow each one actually puts out. I do know the pass on the way to Escalante, UT has more snow than I've seen in a long time.
Now as long as we can keep the environmentalist from getting 20 feet drained from the lake to save some endangered mosquito....Maybe the lake would stay up for a while.
 

Waterbaby

Moderator
Staff member
#7
Don't discount the San Juan - some years the northern drainage has been well below normal and the San Juan drainage well above, this very scenario brought us up from a very big drop a few years into the drought......for many years at the start of the drought the Green River drainage was pathetic as the snow levels in the areas feeding into the Green were lucky to hit 80% of normal, but luckily the drainage in the San Juan was over 100% at the same time... the biggest hits we took were the years when there was little snow to be found anywhere or the winds came in the spring and wiped it out throughout the drainage.... it is all the luck of where the storms land, whether the winds come and stay, and how low or high the lakes above Powell are, and how they pulse storage above Powell in Flaming Gorge and Navajo lakes to keep fish in the river happy when it is time to spawn.......
 

Dorado

Well-Known Member
#8
In terms of annual acre feet of water (average), the Green is bigger than the Colorado..... But back to the original question; what it the average relative contribution of each drainage? I have wondered this myself, and am not sure where to get that information. Probably could Google it...

I am pretty sure that the relatively arid drainages in southern Utah do not contribute much compared to the upper Colorado and Green River Drainages....
 

Dave I.

Well-Known Member
#9
What's funny is there seems to be a debate as to which one contributes more to Lake Powell, but the fact is that the Green River drains into the Colorado River. At that point it becomes the Colorado and the Green no longer exists. Therefore, technically, the Colorado obviously contributes more to Lake Powell. haha

But seriously, I think it does really depend on the snow storms in each area each year. It's been dry for to many years, it's exciting this year.

The southern part of Utah usually doesn't contribute a large quantity of water usually. The pass going to Escalante, UT drains into the Fremont River which comes thru my property and it is very small compared to the Colorado and the Green. It is here in Hanksville where the Fremont flows into the Dirty Devil. But I just drove that pass this month and there is a lot of snow up there.

End result is the lake is going to really benefit from all the tributaries this year. Very exciting!
 
#11
So I did a little digging today, not as much as needed, but I find a few indicators on which rivers have the greater contribution to the water flow to Lake Powell. The Colorado River measured at Cisco Utah provides about 40% of the flow, the Green River at Green River, UT provides about 40%, the San Juan at Bluff, UT provides about 15%, and all of the others in Southern Utah like the Dirty Devil, San Rafael, Mill Creek and Escalante only provide about 5%. I've always known those southern Utah rivers provided just a small fraction. But what I'd really like to see is how much those others like the Roaring Fork, Gunnison and Duchesne provide.
 

Waterbaby

Moderator
Staff member
#13
Heavy snow from this storm in the high country and the White Mountains. This will help the Arizona lakes and what drains into the Little Colorado ends uo in Lake Mead, since it is snowing heavy on both sides of the Grand Canyon this will also help Lake Mead and since it is moving into Colorado it will help boost the snowpack for Lake Powell, too!
 

WaterMan

Well-Known Member
#14
Roosevelt Lake was at 59% today and Bartlett Lake was 100% with 0.29' remaining. SRP water shed is at 70%, all we have left to fill is Roosevelt with 37.21' remaining to full.
This rain should help with Roosevelt Lake. All lakes are under 5' or less remaining.

The Little Colorado was at 88% snow pack this morning. The majority of the snow was to hit the west end of the Mogollon Rim. and a little snow for the White Mountains.
We will see tomorrow if the snow pack goes up. The SAN FRANCISCO PEAKS was the best at 199%.

This storm is staying south and heading to the Four Corners to Colorado.
 

WaterMan

Well-Known Member
#17
AZ got so much snow they can't even get readings.:p

ARIZONA SNOTEL Snow Water Equivalent Update Graph
As of TUESDAY: FEBRUARY 28 , 2017
Basin Snow Water Equivalent Percent of Median
VERDE RIVER BASIN *
SAN FRANCISCO PEAKS *
CENTRAL MOGOLLON RIM *
LITTLE COLORADO - SOUTHERN HEADWATERS *
UPPER SALT RIVER BASIN / WHITE MOUNTAINS *
SAN FRANCISCO / UPPER GILA RIVER BASIN *
CHUSKA MOUNTAINS *

Legend:
<70%
70-90%
91-110%
111-130%
>130%
 

Waterbaby

Moderator
Staff member
#18
AZ got so much snow they can't even get readings.:p

ARIZONA SNOTEL Snow Water Equivalent Update Graph
As of TUESDAY: FEBRUARY 28 , 2017
Basin Snow Water Equivalent Percent of Median
VERDE RIVER BASIN *
SAN FRANCISCO PEAKS *
CENTRAL MOGOLLON RIM *
LITTLE COLORADO - SOUTHERN HEADWATERS *
UPPER SALT RIVER BASIN / WHITE MOUNTAINS *
SAN FRANCISCO / UPPER GILA RIVER BASIN *
CHUSKA MOUNTAINS *

Legend:
<70%
70-90%
91-110%
111-130%
>130%

I had a feeling when I watched the weather report on the local news last night. It was a cold rain here yesterday and it rained without letup literally all day and until around midnight last night... this is very good for all our lakes.
 

WaterMan

Well-Known Member
#19
The site is back up. Here are the graphs for today.
As of TUESDAY: FEBRUARY 28 , 2017
Basin Snow Water Equivalent Percent of Median
VERDE RIVER BASIN
107%
SAN FRANCISCO PEAKS
207%
CENTRAL MOGOLLON RIM
110%
LITTLE COLORADO - SOUTHERN HEADWATERS
106%
UPPER SALT RIVER BASIN / WHITE MOUNTAINS
62%
SAN FRANCISCO / UPPER GILA RIVER BASIN
57%
CHUSKA MOUNTAINS *

Legend:
<70%
70-90%
91-110%
111-130%
>130%
 
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