Now that the surface temp at Fork is hovering around 90 degrees most days I am curious what the temp would be at 10 feet, 20 feet & beyond.

I always wanted to buy a good temp gauge and drop it down and record the temps at various depths in the heat of the summer and the dead of winter.

Has anyone ever done this?

Great idea. Very interesting

I know about 6 ft down it feels cooler. that's all I've ever figured out.

It does not drop a lot till it hits the thermocline.

Back when I had a Color-C-lector there was a temp drop of a couple degrees in the first 5 feet but after that almost no temp drops till you hit the thermocline.

I have seen Bill Dance talk about it and use a thermometer at different depths and get readings. Maybe go research him and you might find it and what he was using.

With my lack of scientific data I can’t argue as to how many degrees temps rise or fall at certain depths but who as a child didn’t swim down just 10’ or so in our reservoirs and didn’t experience way cooler water during the summer? I have dove(SCUBA) in several lakes in Texas and temps drop substantially as you go down in the summer. Would be interesting to see some actual numbers.

Look for the thermocline. If you can find it and water in the mid 70s, you have found where 80 percent of the fish in the lake want to be. Doug Hannon did a lot of looking at this. Bill D was a great advocate of it. I started doing it with a lowrance temp guage with 40 feet of wire on it. Then bought one of the early Color-C-Lectors and continue to use it today.

I have been looking at this one:

https://fishhawkelectronics.com/fish-hawk-td/fish-hawk-td/

But have not pull the wallet yet.

Never have done it but you just gave me an idea on what to do with old broke, as in broke off mount bracket, ducer. Put a weight on it and drop it down with it hooked up to unit instead of mounted one.

I was an experienced SCUBA Divemaster at one time, and was used to ocean temps from surface to 110' on the east coast of FL. Summer was mild temps all the way to 60' and just a little cool below that. When I had occasion to do an object recovery dive in a freshwater lake (not spring fed), I was amazed at: 1) how quickly it got dark given that I did not rate the water as "low visibility" as Florida lakes go, and 2) how quickly it got COLD! I had to abort to come back with a dive-light even for the middle of the day - in less than 20' of water. It made me wonder just how much color can actually be seen at those depths.

The Applied Research Lab at UT Austin monitors temperature of Lake Travis down to 40 feet.

Lake Travis Test Station

Temp varies from about 77 at 40 feet to 85 at surface.

Good info. Is there ever any current in Travis?

I've jumped into the lake to cool off many times on Fork in July & Aug. You can feel a marked difference 6-8' below the surface.

Yesterday I jumped in my pool that was showing 90 at the time. I turned on the pool fill to bring the water level back up as there is a lot of evaporation this time of year. The water from the filler comes off the hose bib, felt at least 5 degrees cooler.

The Color-C-Lector will give you all the information. The most valuable part of it is the Oxygen content reading. Any device like this is time consuming to use while trying to fish and the interest in using one falls by the wayside quickly. You are going to get a few degrees cooler in almost every lake at 10 ft.. Lakes that have the thermocline gives you the coldest drop and very low oxygen below that line. Your fish will be working above the line; but will chase below it. They just will not stay below it for very long. This can even change form one area of a large body of water to another area.

Your depth finder will show the thermocline and I used that depth to locate fish quickly and stay on them as the water a few feet above it was cooler and the Oxygen level above it was high. When fishing shallow water the Oxygen level is the most important knowledge you can have. In dead still water the oxygen level is the most important reading to have. Many times the only thing that can help with this when you are in a hurry, is plenty of wind blowing into the area you are fishing. Wind also delivers lots of other factors to support Bass other than the Oxygen.

Probes are interesting; but time consuming. Use the fast track theories instead.
- Fish the mid-range dept to find cooler water.
- Fish above; but near the Thermocline.
- Fish Heavy Cover on wind blown high Oxygen areas.

I don't think the original Color-C-lector measured Oxygen saturation. That's a tough thing to measure - the equipment to do so was expensive back in the day I checked into it.. The Color-C-lector I STILL have measures pH if I remember correctly. The "color" part of it is just bands placed on the dial face of an elaborated pH meter, I believe. I have not had it out of the case in 20 years; I'll pull it and see if I remember any of this correctly.

Update: I pulled out my top-of-the-line model "Combo-C-lector" unit. It has a 4 position switch for OFF & 3 different parameter readings, but NOT oxygen saturation.