Whitewater Forum: Sky Gauge
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Sky Gauge

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Category: General
Forum Name: Whitewater Forum
Forum Discription: Open Discussion Forum. Whitewater related subjects only
URL: http://www.professorpaddle.com/forum/forum_posts.asp?TID=15084
Printed Date: 28 Feb 2024 at 7:06pm

Topic: Sky Gauge
Posted By: megspk
Subject: Sky Gauge
Date Posted: 13 Oct 2015 at 11:29am
So I'm not sure if I'm just not used to seeing actually water in the Sky or what, but I'm feeling like the gauge is reading a bit lower than what I'm seeing. Yesterday they gauge read around 2600-2700 when I was out there, but it seemed closer to 3500 or so.

Any locals or people that have this run memorized agree or disagree?

The rock at the exit of Boulder Drop on river left, that's kinda shaped like a whale's tail, was almost all the way under water yesterday (def no rock showing). Also ledge drop at the base of BD was really filled in and didn't really have any exposed rock.....

A strong person and a waterfall always channel their own path. -Unknown

Posted By: Ellingferd
Date Posted: 13 Oct 2015 at 12:41pm
seemed accurate on sunday...

Wave Sport

Posted By: Slackkinhard
Date Posted: 13 Oct 2015 at 1:00pm
I was out early on Sunday to see the high water. Gauge read 9600+ and it looked like it. Water piling up and sometimes cresting house rock, mercy chute wide open, almost an eddy the river was so wide. By noon it had settled down to about 8000 and big rocks were well above water. By 3:30 that day it had dropped to about 6000 and I putin at cable drop, portaged boulder and got out at split rock.  By the time I reached the takeout it had prolly dropped to 5500.
I went again yesterday afternoon about 5pm and it was down to about 2400. This morning the gauge reads 2380 as of 8:30pm last night. When I went to the USGS site, it said 2680.

It seems about right.  Not sure at what level the rock in the center of the weir drop gets covered up?

my $.02

Posted By: tiziak
Date Posted: 13 Oct 2015 at 3:51pm
You gotta remember to account for level rising and dropping.

When I woke up, I checked level and I think the gauge said 9K and going up 300ish cfs an hour. A few hours later it was in the 6k range and dropping over 500 cfs an hour. 6k and dropping 500cfs and hour (basically a full on tributary every hour) is not gonna look or feel the same way a static 6k will feel in the Spring.

Make any sense?

If you don't know where you are going, any road will get you there.

Daniel Patrinellis

Posted By: huckin harms
Date Posted: 05 Nov 2015 at 7:31am
Based on my experience the gauge is off by at least 1k. Yesterday's run revealed this to be the case. Gauge reading was 4800 but felt and looked like 6k, based on a several rocks I've used in the past for levels.

No major changes, NF channels are deeper, a slightly new iteration below House rocks in BD, and Split was 'in' fluffy.

Gotta love having snowpack back in the mnts as it keeps the river up higher for longer!

Posted By: mprussak
Date Posted: 05 Nov 2015 at 12:09pm
I think this was posted before the big rains, but that would make sense, the sky gauge wound up off by about 2k after last year's flood iirc.

Marek Prussak     206-465-2055

Posted By: Sam_Graftton
Date Posted: 05 Nov 2015 at 10:50pm
The gauge has been off since last November. It seems the higher it gets the more off it is...

Posted By: LisaF
Date Posted: 06 Nov 2015 at 5:00pm
If the gauge is off, it's most likely off by a percentage (which would explain Sam's comment). So, if Harms says it felt 1000 off at 4800, that would translate to about 20%. So, a reading of 2000 might feel more like 2400; 1000 more like 1200 (I think I noticed that myself last summer). Also, keep in mind that the gauge is at Goldbar, which is a bit downstream of the main run. If you figure water moves at more-or-less 4-6 MPH, and the gauge is 6 miles below where you're paddling (just a guess, I don't know exactly how far down it is), then a rapidly rising or dropping river would, necessarily, not be reflected on that gauge reading (I'll let someone else do the math; it's not my strongest subject).

Posted By: huckin harms
Date Posted: 07 Nov 2015 at 7:58am
Yes, I would agree with you. The higher it gets, the more off it goes.

Posted By: Slackkinhard
Date Posted: 11 Jan 2016 at 3:20pm
gauge correction?  I've felt like the gauge has been reading higher than it really is lately....today there seems to have been a change?  I've seen it do this before, so maybe it's just me.

Posted By: Jed Hawkes
Date Posted: 11 Jan 2016 at 3:35pm
That little blip you see can be lots of things. The USGS page says that it can be ice affected. Remember that the number you see posted on the site might not be the most accurate number, be sure to use all data points. If you look at the USGS page and the NWRFC page they are all posting different information.

If they do a gauge update you will see a note on the USGS page that tells you when and what they did. My guess is that they won't adjust the gauge for a bit unless it's wildly off and affects their ability to determine flood levels. Realistically the gauge being off a couple hundred cfs on a drainage this large doesn't warrant them updating it let alone in the middle of winter.

It's likely blipped because it starting to rise.

The line will become apparent

Posted By: huckin harms
Date Posted: 02 Feb 2016 at 2:17pm
So the gauge is off again. Reading lower than what's actually in the river. I'm guessing it's off by 700 to 1k cfs. It's really hard to judge with all the recent flood related changes.

Posted By: Sam_Graftton
Date Posted: 02 Feb 2016 at 7:14pm
I'll second that today felt a lot more like 4,600 then 3,600

Posted By: dave
Date Posted: 03 Feb 2016 at 3:36pm
You guys should leave your comfort zone and journey to the Upper Green sometime, it has been spectacular at 2,500 -3, 000 lately! Also the gauge is accurate...


Posted By: James
Date Posted: 03 Feb 2016 at 8:09pm
^---- He just said comfort zone to Sam...

When ever I am constipated I load one of Sam's clips, does the trick in about 15 seconds.

Posted By: dave
Date Posted: 04 Feb 2016 at 8:00am
That seems to be the phrase that everyone is using these days...


Posted By: Jed Hawkes
Date Posted: 04 Feb 2016 at 9:47am
Originally posted by dave

That seems to be the phrase that everyone is using these days...


The line will become apparent

Posted By: jP
Date Posted: 04 Feb 2016 at 11:50am
Originally posted by Slackkinhard

gauge correction? I've felt like the gauge has been reading higher than it really is lately....today there seems to have been a change? I've seen it do this before, so maybe it's just me.

Ok here is the answer to your quandary. You aren't Slackin as Hard as your moniker implies- you've an
avid pressence on this forum and on the river. But, like a lot of boaters on the scene you are a relative new comer. So the nuances of detail throughout the river escape your attention, no matter how observant you may be. This is natural. Such details are quite subtle. But over time you get so familiar with your environment that you know what you are observing.

After a few decades of observing rivers and specifically about a dozen trips down the Sky since these last 4.5 floods, I have come to know, with confidence, what I'm observing. I'll share that now...
The river bed as we know it in a general sense has a certain depth to it, as we've grown to be familiar with it in our 'lil geological blink of an eye.

So, when the sky is running 6,000 cfs for example, the picket fence has had the peaks of its rocks visible, but the spaces between them are filled in. i.e Ned's Needle, The Needle Proper, and Paul's Needle all have pretty full channels. Keep in mind that "The Bubble Pool" (proper name) located immediately upstream of the Picket Fence (Also a Proper Name) has been a very very deep pool the whole time we've known the Sky. This deep pool has provided slack water and is the saving grace for raft guides as they try to line up for the needle. This slower water has also helped many a kayaker rescue or self rescue above the Picket Fence. "The Bubble Pool" is likely filled in with some extra gravel now. That is going to effectively Raise the Level of the River Bed.This is evident by comparing the guage reading with the waterline on boulders, such as those at the Picket Fence.

I feel like my recent runs through the standard raft entrance are kicking me through the bubble pool faster than before the recent floods, but the extent of this could be partially or entirely in my imagination. Repeated runs through at varying water levels will reveal the truth, unless that 32,000 spike last week altered things further, which it probably did. Although, this time, it probably scoured and scrubbed out a *small* amount of these recent gravel deposits.

The "Raised River Bed Due to Fresh Gravel Deposition" Theory is quite evident elsewhere throughout the run, most notably from the Confluence to the bottom of BDrop. Anderson Hole is perhaps the most striking example because there you have a relatively Simple, Flat and Wide river bed with a simple composition of just a few medium sized boulders. Flows between 3-4,000 give Anderson Hole a much more filled in look, with the boulders nearly pouring over. It looks more like 6-7,000 there, loosely speaking.

Again: wide and uniform distribution of gravel across the whole run from top to bottom, from bank to bank. (and that's a slight exageration for conceptual purposes)

My theory: Baseball to bowling ball sized gravel, an amount big enough to fill...20 dump trucks, let's guess. "Baseball to Bowling Ball size". I postulate this because that size range is small enough to easily moved around, yet big enough to stay put unlike sand and finer gravel. So when I say "gravel" I'm talking about "Cobble". You and I could unload a dump truck full in a day and move it somewhere with wheel barrels. Might not be fun, but from a logistics standpoint its doable. It's logistically doable for the river, too, except it probably enjoys moving that sh*t around. I know I would, If I was a Skykomish River

Not My Theory, Just observation: All of this came out of the North Fork. This is obvious paddling down form Index to the confluence, most notably in "Powerline" Rapid. (Not Cable Drop- that's on the S. Fork, and the power lines cross both forks duh) Powerline (I'm hearing people call it "Toothpaste", but I never heard that name before and I been around awhile. Guys, stick with or find out what the original names are- its less confusing) Anyway, Powerline (for lack of a better name) is completely different now much to the consternation of the esteemed Mr. Harms and probably Sam too since that big monster hole that used to form at high water is gone now.

The NorthFork has miles of that kind of gravel. If you've put in at or above Trout Crik you know what I'm sayin. Well now a large share of that gravel is below the confluence but above Aquagasm (Lunch Hole Proper looked consistent with my theory at 1900 cfs. Similarly, Any large amounts of gravel being pumped and rolled down the South Fork won't make it to the confluence because you got Eagle Falls, Canyon Falls and Sunset Falls to cull out those deposits. Big drops have big pools. And Otter Slide and Cable Drop can arrest any gravel that manages to get that far, not to mention the flatwater from there to the bridge.

Having a large pool above and below each rapid is obviously a very common attribute of whitewater anatomy. These pools are perfect for recieving these deposits, leaving less gravel to proceed into the next rapid.

But 32,000 is the low end of "Flooding" according to NOAA/USGS. Its wasn't severe enough or in series like the other events to bring down more gravel. No, last fall the North Fork PUKED HARD. Now the job of a 32,000 cfs event would be, I suspect, to "Tidy Up" or Sweep Away" some of that loose material that rests on top of the more firmly bedded deposition. Because that is Definitely enough water to move the gravel deposits we are talking about. So I'm sure its changed yet again, but not as dramatically.

Hope that sheds light on everyone's questions about why the guage seems off (if you're still reading it means you were interested enough). Keep in mind the gauge is in Gold Bar. While the Cross section it measures may shift and change (gravel bars down there in the glacial valley), it is still just a measurement of volume and time. 6,000 cfs is 6,000 cfs. So the Gauge isn't "Off". The River is "Off". but, The River is The River, so it can't be "Off". That means the only ones left who can be "off" are... Us.


Posted By: Slackkinhard
Date Posted: 04 Feb 2016 at 12:16pm
great info....thanks jP

Posted By: huckin harms
Date Posted: 04 Feb 2016 at 10:33pm
Yeah, I saw that cross-section. I'm still trying to deal with my part being 'off'. All those years of experience 0000 washed away. It's hard starting over...   the way of nature.

I think your general analysis of the changes to the river bed are spot on, hence the misinterpretation of the gauge reading. What once was, is now gone. Se la vie

Posted By: Sam_Graftton
Date Posted: 05 Feb 2016 at 1:13pm
Well said JP, I'm stoked low water just got a lot better!

Posted By: megspk
Date Posted: 05 Feb 2016 at 1:40pm
JP your posts are the best. Too bad no one has snorkeled and documented the riverbed. That would be really neat.....looking forward to differing flow adventures on the Sky!

A strong person and a waterfall always channel their own path. -Unknown

Posted By: Slackkinhard
Date Posted: 05 Feb 2016 at 5:35pm
I've spent a lot of time upside down looking at the bottom of the sky....rocks....lots of rocks

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