South Sauty USGS - Bucks Pocket correlation

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gwpartain
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South Sauty USGS - Bucks Pocket correlation

Postby gwpartain » Tue Dec 01, 2015 9:22 pm

Adding this post to gather visuals of the Bucks Pocket stick gauge to compare to the USGS South Sauty gauge (http://tinyurl.com/usgssauty). This data will be used to refine or validate the current correlations for the flowpage. Please post your visual of the Bucks Pocket stick gauge in inches and the time of your reading. The more entries the better, even if your particular level has been reported in the past.

Similar to the prior data gathering effort we will keep an accumulated list of the readings in this thread.

Note:
The previous post (http://alabamawhitewater.com/alwwforum/viewtopic.php?f=2&t=10535) gathering data has been locked and *unstuck* to keep the readings prior to the gauge repair, separate from the more recent readings. Thanks to all those who gathered readings for that post. That data will still be used for a long running comparison.
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Re: South Sauty USGS - Bucks Pocket correlation

Postby Samurai Chuck » Tue Dec 01, 2015 9:50 pm

Last Update: January 26, 2017
Note: Old stick gauge was wiped out in the Christmas flood; was replaced recently and aligned with previous correlation values--correlation still holds.

Please post any levels, with time of day and date observed here and I will keep this post, and the correlation updated.

Current linear correlation is roughly ( USGS X 8.9 ) - 67 = Bucks Pocket Stick reading in inches. Current correlation stick height error is roughly ±2 inches.

Current correlation. Find USGS gauge height on X-axis, go up until you hit the correlation line, that is your estimated stick height in inches on the Y-axis.

Image

Image

Just a little background. I wanted to keep the original correlation effort going, so I took all levels from the previous forum post, compiled them in an excel file, then gathered all levels that I had logged on my own, and any levels I found with dates and times from facebook, emails, etc, to get as much recent data as possible. I noticed that somewhere around late 2012, the gauge must have shifted because there is a noticeable difference in pre-2013 (blue) and post-2013 (orange) correlation. Additionally, there was a note in February 2015 on the USGS page that the Sauty gauge underwent repair due to "extensive damage". So far, this doesn't seem to have affected the correlation, but I may further refine the date range once we get more data going forward.

Image

So, I separated the two and will maintain a 2013+ correlation, as well as a comparison correlation for the purposes of seeing how far from the original the new correlation becomes.

Of course a few factors will always affect the use of this gauge.
1) USGS gauge is upstream of put-in and Kirby creek, a major tributary. This will cause the USGS gauge to read higher than the stick in some cases if the water hasn't reached the pocket yet, or if rain was locally heavier in Sauty, but not Kirby. It could also cause USGS gauge to read lower in some cases if the rain was recent, or heavy amounts fell very locally into Kirby, which won't register on the USGS gauge.
2) The correlation is subject to changing ground water conditions, so towards the beginning and end of the season, or if it has been a few weeks since a big rain, the error will increase and may be off several inches. It should be quite reliable in the main winter months in the main boatable range of 12-24 inches.
3) There is always a risk that some new cave will open changing the correlation completely, like what happened before. If the readings start drifting way off, we'll tackle that when it happens.
Last edited by Samurai Chuck on Thu Jan 26, 2017 9:42 am, edited 6 times in total.

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mr ray
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Re: South Sauty USGS - Bucks Pocket correlation

Postby mr ray » Fri Dec 04, 2015 1:44 pm

This is great, guys! Thanks so much for doing it!

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Re: South Sauty USGS - Bucks Pocket correlation

Postby chris a » Mon Dec 07, 2015 7:55 am

The level was dead on with your graph this past weekend. Great job!


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