thermocline levels?

[bassman_ky]

Does anyone know how to check thermocline levels on the internet? If so could you point me in the right direction.

[Grumpy]

Four years ago, the Corps of Engineers started publishing WATER QUALITY DATA on its Louisville site and I have found that you (i) can use this data to determine the APPROXIMATE depth of the thermolcline.

I will show you my unscientific means of finding the thermolcline using the COE web site listing area lakes:

http://www.lrl.usace.army.mil/wc/reports/lkreport.html

After the lake list comes up, click on the (blue) name of the lake you want. e.g. NOLIN.

When the Nolin page comes up, click on the LAKE TEMPERATURES, then at the top of the temperatures page you will see a line that says: "Click here to see raw date for this lake reservoir" click on it. You will get a listing of depths with temperatures and oxygen levels at each depth.

The traditional way to determine a thermolcline was to use a thermomitor to find a place where the temperature drops rapidly in a space of three to five feet. You can look for that on the WATER QUALITY DATE site of a lake but I have found that it is easier and clearer (to me) to use the OXYGEN level data to find the thermolcline. My understanding is that the oxygen levels will drop off very fast at/in the thermolcline, just like the temperatures do. I also understand that the fish will not be anywhere, where there is little or no oxygen so using these charts, I look to see the depths at which there is little or no oxygen and fish above that level.

Anyhow, I look for an area where the oxygen level drops fast in just a few feet. e.g. using the Nolin page for 09/22/08, you will see that at 25' the oxygen level is 7.3; then at 30' its 5.0; then at 31' its 2.9, and at 32' its 0.7.

For my purposes, I figure the Nolin thermolcline was at about 30 to 32 feet below the surface. It probably was somewhere around 27 or 28 feet to 32 feet but they don't list one foot increments in this example.

Anyhow, once I am sure that a thermolcline has set up in the Spring or Summer, I concentrate my fishing at dephs SHALLOWER then the thermolcline that I figure from the COE data. It is really pretty easy since I don't like to fish deeper thant 25 to 30 feet anyhow.

Hope this helps and if someone else has another site, please share it will all of us.

Grumpy

[bassman_ky]

I really appreciate the info. That is exactly what I was looking for.

[fishing4kids]

Survivable oxygen levels for bass range from 5 to 13 parts per million (ppm), though they highly prefer and will seek out waters with 9 to 12 ppm oxygen. If the oxygen level falls below 3 ppm, the fish will die of asphyxiation. And if they remain in areas with more than 13 ppm, they will experience oxygen poisoning.

And the corps graph shows mg/L ---- 1 ppm = 1mg/L

Eddie

[Grumpy]

Eddie,

Either there is is typo or I am missing the point of your post: if 1ppm equals 1mg/l then they are both the same just using different mediums of measurments, so it wouldn't make any difference which they used. in the graph.

Grumpy