Nolin Water Temps

[Grumpy]

Thanks, Wizzard.

[fishing4kids]

Grumpy ,
at what temp do you think it turns over on Nolin?

Eddie

[Grumpy]

Eddie, the short answer to you question is at about 60 degrees. But if you want my explanation, keep reading.

Believe me I am not an expert in any of the stuff I am about to write about, but my reason for trying to determine when the Fall Turnover occurs is to be able to be on the water when the Fall Feeding Frenzy occurs. I think that the Feeding Frenzy starts after the temperatures and oxygen levels equalize (become the same/constant from top to close to the bottom) after the Turnover.

Sometime toward the end of September (in most years) the water will start to cool from its Summer time highs and this will cause the shad to move into the creeks and Bass will go after them. I call this the pre-turnover feeding frenzy, although it is not generally as frantic as the Fall Feeding Frenzy.

The pre-turnover feeding frenzy usually occurs in the creeks and longer coves, off the main lake, that are shallower then the depth of the lake’s thermolcline. The water/oxygen in the creeks/coves will be the first to mix but there won’t be a true “Fall Turnover” because there is not a Thermocline it these shallower areas.

Anyhow, I have watched the Corps’ Water Quality Data for the last couple of years. This year, as of September 22nd, the Thermolcline was at about 25 to 30 feet and the water temp. was about 75 degrees. At about 40 to 45 feet, which I think is a good average depth for Nolin, the temps were about 63 to 65 degrees. According to the “experts” that I have read, the Thermlcline will be at a constant depth throughout a lake. In other words, if it is a 30 feet at the dam, it will be around 30 feet everyplace in the lake that is 35 to 40 feet or deeper (there has to be room below the thermocline for the bottom layer to set up).

I think that when the surface water cools to about 70 degress, the water ABOVE the Thermocline will start to mix but not break through the Thermocline. When the upper layer cools to about 60 degrees (in this example) it will break through the Thermocline and cause the whole water column to turn over and mix from top to bottom, When this happens, the oxygen content is all mixed up along with all the muck and debris that comes up from the bottom and lower depths. After the Thermocline breaks up, I think it takes about seven to ten days for the water to stabilize and then the Fall Feeding Frenzy begins. Obviously, all of these timeframes, depths and guesses can vary greatly depending on when the weather changes or doesn’t change also on how fast or slowly it changes,..

The bottom line is that IN MY OPINION in most years the Fall Turnover and the Fall Feeding Frenzy happen sometime in between late September and the middle of November, but generally sometime in October. I love fall fishing, except during and right after the Turnover.

OK, now all of you others can chime in and tell me what you think.

Grumpy

[greenriverman1]

Grumpy,

Doe's the draw down fit into this? My understanding is that the draw down is takeing place at this time.

DA

[Grumpy]

Grumpy,

Doe's the draw down fit into this? My understanding is that the draw down is takeing place at this time.

DA

Greenriveram1, I think that the drawdown plays a MINOR role in the initial mixing of the water above the Thermolcline in most years. If we have an unusually long, warm Fall and the turnover is late, then it may play a bigger part. My reasoning is that Nolin starts a slow drawdown in September but doesn't pull the plug intil the first of November and by thet time, usaully, the Fall Turnover has happened.

Grumpy

[00SKEETER]

Greenriveram1, I think that the drawdown plays a MINOR role in the initial mixing of the water above the Thermolcline in most years. If we have an unusually long, warm Fall and the turnover is late, then it may play a bigger part. My reasoning is that Nolin starts a slow drawdown in September but doesn't pull the plug intil the first of November and by thet time, usaully, the Fall Turnover has happened.

Grumpy

I don't think Rough, Barren or Nolin have started the winter draw down. I think they're holding off until Oct.22. Correct me if I'm wrong but usually they start the slow draw on Sept. 15 and pull the plug Oct.15. on these lakes. I would say they're holding the lakes because of the dry summer we've had.

[greenriverman1]

Headlines in the Edmonson News stated in the Oct. 2nd. issue that the Corps has started the fall drawdown. The paper said the drop would be from 515 in mid Sept. to 513 by mid Oct and then by the end of Nov. they should be at winter pool at 492.

DA

[Grumpy]

OOSKEETER, you could be correct but the way I see the Corps listing, each of those lakes have a different start and end date for the Drawdown. I was referring to Nolin in my example above. Rough is the only lake I heard that they are holding untill the end of Oxber.

Grumpy

[CTFSHWHISKER]

rough is down about 2 feet..72 and bubbling with some places of black,coffee water.

[MsgMills]

Nolin, down 2 feet from summer pool...Water fairly clear to slightly stained on the main lake and up into some coves.... Water in creeks and main lake was anywhere from 70.2 to 75.7...No signs of turnover at all.....

[fishing4kids]

Eddie, the short answer to you question is at about 60 degrees. But if you want my explanation, keep reading.

Believe me I am not an expert in any of the stuff I am about to write about, but my reason for trying to determine when the Fall Turnover occurs is to be able to be on the water when the Fall Feeding Frenzy occurs. I think that the Feeding Frenzy starts after the temperatures and oxygen levels equalize (become the same/constant from top to close to the bottom) after the Turnover.

Sometime toward the end of September (in most years) the water will start to cool from its Summer time highs and this will cause the shad to move into the creeks and Bass will go after them. I call this the pre-turnover feeding frenzy, although it is not generally as frantic as the Fall Feeding Frenzy.

The pre-turnover feeding frenzy usually occurs in the creeks and longer coves, off the main lake, that are shallower then the depth of the lake’s thermolcline. The water/oxygen in the creeks/coves will be the first to mix but there won’t be a true “Fall Turnover” because there is not a Thermocline it these shallower areas.

Anyhow, I have watched the Corps’ Water Quality Data for the last couple of years. This year, as of September 22nd, the Thermolcline was at about 25 to 30 feet and the water temp. was about 75 degrees. At about 40 to 45 feet, which I think is a good average depth for Nolin, the temps were about 63 to 65 degrees. According to the “experts” that I have read, the Thermlcline will be at a constant depth throughout a lake. In other words, if it is a 30 feet at the dam, it will be around 30 feet everyplace in the lake that is 35 to 40 feet or deeper (there has to be room below the thermocline for the bottom layer to set up).

I think that when the surface water cools to about 70 degress, the water ABOVE the Thermocline will start to mix but not break through the Thermocline. When the upper layer cools to about 60 degrees (in this example) it will break through the Thermocline and cause the whole water column to turn over and mix from top to bottom, When this happens, the oxygen content is all mixed up along with all the muck and debris that comes up from the bottom and lower depths. After the Thermocline breaks up, I think it takes about seven to ten days for the water to stabilize and then the Fall Feeding Frenzy begins. Obviously, all of these timeframes, depths and guesses can vary greatly depending on when the weather changes or doesn’t change also on how fast or slowly it changes,..

The bottom line is that IN MY OPINION in most years the Fall Turnover and the Fall Feeding Frenzy happen sometime in between late September and the middle of November, but generally sometime in October. I love fall fishing, except during and right after the Turnover.

OK, now all of you others can chime in and tell me what you think.

Grumpy

Thanks Grumpy for your insight. I would say you hit the nail on the head.

Eddie