Email from Corps: Tailwater D.O. Improving

[Phil Lilley]

Subject: Change in recommended maximum generation rates

The cold spell has greatly aided in the recovery of all the lakes.  Some short term heavy generation test have shown that tailwater D.O. levels remain well above 4 ppm at Table Rock, Bull Shoals, and Norfork.  The recommended maximum generation rates at all 3 are now 100% nameplate, or 50Mw per unit at TR, 40Mw units 1-4 and 45Mw units 5-8 at BS, and 40 Mw per unit at Norfork.

The next step is closing the vents whenever the D.O. levels remain above 6 ppm.  That could happen in another week or less.

Steve Bays

[cracklebak]

Phil, can you translate that for us? Guess I haven't heard what the vents do.  What I am hoping this means is the big spikes in generation may slow down a little- makes it tough! Been 2500 cfs up to 10,000 cfs seems like daily. Trying to plan our next trip down but haven't done well in the last six weeks down there.

I did find this on Wikipedia- " Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, or maximum effect, is the intended full-load sustained output of a facility "

[Phil Lilley]

In the fall each year, the Corp puts limits on how much water they can run through the turbines because of low DO.  They can keep the DO at 4 ppm (the lowest they can go by their standards) by injecting liquid O2 into the water as it goes through the turbines and by opening vents in the turbine chamber allowing the water to slosh around with the air.  When the DO is high enough, they will shut the vents till next fall.

As Table Rock's water turns over and mixes, which sometimes happens quickly but this year it's happening gradually, the Corp starts to lift the restriction that have on generation.  Right now they're not running at full capacity because the DO isn't up over 6 ppm.  When it reaches 6 ppm, which shouldn't be long seeing it's 10 degrees outside, then they will lift all restrictions and run water at 4 units full.

This all has nothing to do with their generation schedule though.  It's not unusual for them to run water fairly hard early and late in the day on cold days - power demand.  What is kinda unusual is them running 35-50 megawatts all day but that's been a pattern all year.

[cracklebak]

Thanks for the explanation. Fishing sure has seemed to be sluggish for us- we have been fishing from the dam to trophy run several weekends in the past six weeks. Hoping that when the lake finishes turning over (and O2 goes up, sounds like) that the fishing will pick up for us. It's been super tough. We fish mainly at night, hoping to drop one in front of a big brown. One night I actually caught more non-trout than trout! 2 largemouth, one small mouth, a BIG crappie and a walleye!

[cracklebak]

Am I close in thinking that 35-50 megawatts is something like 2000-4000 CFS if calling in to the automated number?

[Phil Lilley]

Yes- about 704.3 feet level

[cracklebak]

Phil, another question...  @Phil Lilley

 

When I look at the charts that you have sticky posted in this forum it says that DO is way worse at the dam (2-6ppm), but great at college of ozarks (5-8ppm)? Is there a conclusion to be drawn from this? Will fish evacuate to the better water quality downstream (outside of maybe the outlets?) I realize I may be way off base but....Trying to learn... thanks for any input! 

[cracklebak]

bump for ideas/answers

[snagged in outlet 3]

On ‎12‎/‎16‎/‎2016 at 10:22 PM, cracklebak said:

Phil, another question...  @Phil Lilley

 

When I look at the charts that you have sticky posted in this forum it says that DO is way worse at the dam (2-6ppm), but great at college of ozarks (5-8ppm)? Is there a conclusion to be drawn from this? Will fish evacuate to the better water quality downstream (outside of maybe the outlets?) I realize I may be way off base but....Trying to learn... thanks for any input! 

As the water flows downstream it picks up O2 naturally so it will be higher down there.

If you follow the reports you can get a good idea of where the bite is.

[cracklebak]

Ah... I see. so the fish DO follow the good water (or at least those fish where 02 is higher are more willing to bite) Thanks!