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TastyWaves
Super Looper
Joined: 03 Jul 2009
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Posts: 172
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   Topic: Robe in CFS?
Posted: 18 Dec 2012 at 3:49pm |
My brother asked me a few days ago what Robe was at in CFS, I think that day (last sunday) we ran it at 5.4 or so.
Do the veteran Robe wearers have any method for estimating cfs on the run? I gave him an estimate using the "seat of the pants" method and guessed about 600 cfs
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Wise men say forgiveness is divine, but never pay full price for late pizza.
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fiddleyak
McNasty
Joined: 26 Oct 2007
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Posts: 386
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Posted: 18 Dec 2012 at 3:59pm |
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Check out the NWRFC graph. Looks like you guessed a bit low
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WA-Boater
Big Boofer
Joined: 30 Jun 2005
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Posts: 505
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Posted: 18 Dec 2012 at 5:31pm |
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like ben said: http://www.nwrfc.noaa.gov/station/flowplot/textPlot.cgi?id=GFLW1&pe=HG
5.4' = 1014 cfs
5' = 700
5.8' = 1400
6.5' = 2100
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TastyWaves
Super Looper
Joined: 03 Jul 2009
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Posted: 18 Dec 2012 at 11:36pm |
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Duh.. Thanks guys, I forgot the graph had CFS on the right side.
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Wise men say forgiveness is divine, but never pay full price for late pizza.
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TastyWaves
Super Looper
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Posted: 18 Dec 2012 at 11:53pm |
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Ok Darren so I was just going to ask how you got the exact cfs then realized your link was different than the quick graph posted along with the PP listing.
Forgive the ignorance...but out of curiosity how does it work with the conversion? Its obviously not linear but is there a generic formula? Or I guess it would depend based on the volume and size of the river? but I'm just curious how they are able to populate that graph for so many different flows, unless they have archived CFS to corresponding feet based on gauge history??
Would it be possible to mathematically calculate CFS for a given river if all one had was a gauge measuring height in inches/feet?
For instance I found this online calculator to covert feet to CFS for the Poudre river near Ft. Collins:
http://www.poudrerockreport.com/calculator/
How would they go about creating something like that???
Adrian
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Wise men say forgiveness is divine, but never pay full price for late pizza.
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JeffR
Rock Bumper
Joined: 20 Apr 2009
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Posts: 25
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Posted: 19 Dec 2012 at 7:15am |
Here's an explanation of how the USGS measures streamflow. Basically, they measure the cross-section of the riverbed and then measure the velocity of the water at a lot of points along that cross section. The problem with the cfs measurement on the NWRFC site for Robe is that I don't think that measurement has been done in years. The NWRFC doesn't generally perform their own measurements. They usually rely on other agencies to do that, and they just focus on the forecasting. In the case of Robe, the USGS is the most likely agency to measure streamflow since they operate the gauge that the NWRFC center uses to get their data. And the last recorded measured streamflow by the USGS for Robe is from 1980 - there's a 100% chance that the cross section of that streambed has changed substantially since 1980! My guess is that the NWRFC is simply using the last stage-to-streamflow correlation that the USGS measured in 1980.
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hardboof
Paddler
Joined: 06 Nov 2007
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Posts: 51
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Posted: 19 Dec 2012 at 7:25am |
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JEff R you want to go paddle robe now? I just picked up my new boat.
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tiziak
Forum Moderator
Joined: 31 Aug 2008
Location: United States
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Posted: 19 Dec 2012 at 7:36am |
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CFS be damned! Who's looking for some Robe action this weekend?
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If you don't know where you are going, any road will get you there.
Daniel Patrinellis
360.434.4616
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TastyWaves
Super Looper
Joined: 03 Jul 2009
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Posts: 172
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Posted: 19 Dec 2012 at 1:43pm |
Awesome, Thanks for the detailed response Jeff.
Maybe this should spawn a new competition, he or she with the most rolls on Robe this year has to go take the new measurements. Or whoever places last in the Robe race.
Er, nevermind that might be me for both categories I'm doooomed.
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