next full moon.....

[popperonahead]

Anyone got their almanac handy to know when the next full moon will be?

[rango]

august 19th

[big "E"]

I've heard the new moon can be just as deadly , that is tomorrow night from the look of the moon this morning.Might be worth a try.

[popperonahead]

I've heard the new moon can be just as deadly , that is tomorrow night from the look of the moon this morning.Might be worth a try.

as hot as the water is now, i'm going to stick to gills until the weather cools off and some better reports come in for the crappie.... :D

[big "E"]

Hot water up top should mean the crappies are on bottom.My two cents , but that dont mean they gonna bite.

[Moose1am]

Hot water on a lake with little water flowing though it means that the water is hot on top and colder as you go deeper.

You will have three layers of waters in some lakes depending on where the lake is and the shape of the lakes bottom and the amount of water in the lake.

The top layer is hot and then there is a thermocline inbetween the top water layer and the bottom water layer called the hypolimnium. The top layer is called the epilimnium. SP? I didn't get the book out to look up these spellings.

In the summer time the lower water levels can be depleted of OXYGEN. Fish won't be living in this deep water due to the lack of Oxygen. The water will be very cold at the bottom of a very deep lake. Deeper than 50ft or so. Bacteria live in the soil at the bottom of the lake and they feed on dead materials in the mud. These bacteria are consuming oxygen out of the water to survive and they will eventually use up a lot of the dissolved oxygen. Oxgen gets into the water at the lakes surface via a diffusion process. Water from the air above is dissolved into the surface waters. The greater the wind and waves the more oxygen that can get into the surface water. Now in the hot summer months the surface waters oxygen can't get down to the bottom of the lake. The lake's waters are stratified and are not mixing with each other. It's as though someone took a glass plate and stuck it between the top waters of the lake and the bottom waters of the lake. This is the thermocline where there is a sudden drop in water temp in just a few feet change in depth. You have probably felt this when you went swimming and dove down to the lakes bottom and went down thought the thermocline and suddenly got really really cold as you hit the colder water below the thermocline.

Now deep water is a RELATIVE Term. It depend on how deep you are talking about. Bottom can be a relative term to. Bottom at 5ft depth is different than the bottom in 50ft of water. One may be above any thermoclines and the ohter well below the thermocline

So the trick here guys is to find out where the thermcline is in your lake if there is one. The thermoline only exists in the hot summer months and during the fall turnover it's broken up and the waters at the top of the lake can again mix with the bottom waters and then the bottom waters can be REOXYGENATED once again.

But in the hot summer months of July and August the thermoclines will be there in a lot of the lakes in North American. Especially in the South. Maybe not so much up in Canada but in Alabama and IN the lakes will have a thermolcine.

So fish above the thermoclines and you will find the fish. Also crappie can find food (insects etc) in the shallow flats that have weed growing in the water (submergent vegetation) that are producing lots of oxygen.

To find the thermocline you may use the depth finder and turn it up on high using the manual settings. Sometimes the thermocline will show up as a thin line at about 15 to 25 ft. The change in water density can reflect sound waves back up to the surface and make the thermocline visible on your graph recorder.

The other way to find a thermocline is to get a thermometer or thermocouple device and attach a long electrical cable to it. Then you can lower the thermocouple temp recording device down into the water one foot at a time and record the different water temps at the various depths. They make instruments that can do this and they vary in cost. I have access to a YSI temp recording device that I can use to test the water temps down to 25 ft. My cable is only 25 ft long. Wish I had the 50 ft long cable though. LOL


Here is a web site where you can look at a typical summer temperature and dissolved oxygen profile for Patoka Lake in southern IN. The Army Corp of Engineers perform a temp test on this lake once a week during the summer months. I will post the link to the Corps web site that shows the graphs of these lakes temperature and do profile

http://www.lrl.usace.army.mil/wc/wq/prrtext.html

Hot water up top should mean the crappies are on bottom.My two cents , but that dont mean they gonna bite.

[tnvol]

Moose:

Does a man-made lake that has flow thru turbines
have thermoclines? Or...does the on-again, off-again
flow pattern keep the water from establishing them?
I do know that the surface water is still very much
hotter than the water at..say, 7 or 8 ft.

[Fishin_Magician]

I think I can see the thermocline on my sonar unit. (Lowrance LCX-15mt) It appears as a thin light colored line with solid dark pixels filled in below it. I guess the solid area is that dense cold hypolimnium layer. I know if I drop minnows down 12-18' this summer they die allot faster then those up at 6-10'. I like the graph of depth temp and oxygen levels Moose, thx for link.

~Fishin' Magician~

[Moose1am]

It would be hard for me to say for sure. Not without testing the water temps at varous depth. Can you use a depth sounder with the gain turned up high in the manual mode and see the thermocline? That might be the easiest way to answer your question.


It would depend on the depth of the lake and the amount of water volume and then how much water was running through the lake.

Rivers with adequate water flow normally won't stratify.

Also a lot depends on where on the damn the water is released. Some damns have valved at the bottom of the damn and release water from the bottom of the lake which is very cold water. Other dams may run the water though the damn in other areas.

How big is your lake and whats the average depth and how many cubic feet per second do they run though the system? Those are the questions you have to ask without actually testing. It would be far harder to calculate the volume of water in the lake, the amount of heat required to make the lake stratify and the flow though the lake. Those types of mathmatical calculations would involve the use of calcius and a big computer to figure out. Way beyond my expertise.

Does the corp or anyone else do water temp profiles on your lake? They might be able to help answer the question

I do know that small lakes that are only about 20ft deep at the deepest will have a thermocline in the hot summer months. I use to work at a local lake as a life guard. This lake was about 6 to 12 acres in size and I was able to go scuba diving in this lake over the years. I spend a lot of time on the bottom of this lake searching for money and crayfish or just exploring the lakes bottom. I found the thermocline out in the deepest part of this lake. The lake was a public swiming and recreational park and there were concrete docks out in the middle of the lake about 50 yard from the beach. These docks had iron super structures that rose up about 100 above the top of the dock. There was a platform where you stood and went off a swing. Swimmers would swing out over the water and drop or flip into the lake. The area where they had to land was dug out when they built these docks and had the lake drained one year. So that area was about 20ft deep and the water down there was about 70 deg F when the surface waters were in the upper 80's F and low 90's. Now that is a 20deg drop in water temp and even with a wet suit on you feel that colder water. This lake didn't have any flow though it.

The stip pits I fish are about 200 acres in size and have a lot of deep water. The sides of the lake can drop straight down into 50ft of water on one side of the narrow pit and be vairly shallow on the other side. These pits are long and narrow. There is some flow though these three pits as they are connected to each other via 20" diameter culverts that run under some country roads that divide these three strip pits. At times of high water the area is flooded as water backs up from the Ohio River into pigeon creek and then up into blue grass creek then into the North End of blue grass pit. But this normally does not happen in the summer time. So there is very little water flowing though these three pit during the hot summer months.

At Patoka lake which is 8800 acres at summer pool the water stratifies easily in the summer time. The lake's flow is very low at this time of the year. Little rain has occured and they are not letting much water out of the lake in an effort to try to bring the lake up to normal summer pool. But they have to let water out to keep the Patoka River below the damn full of water.

Now KY lake and Barkley Lakes are huge and they have lots of water flowing though them. But since they are so big they still can form thermoclines even with lots of water flowing though the damn.

Hot water will always ride above the colder water even if you still the lake up for a while. So the lake can have the thermocline broken up temporarily and as soon as the flow stops the lake will most likley stratifiy again pretty quickly. You would have to cool all the surface waters down to the temps of the water below the thermocline before the lake would not stratify anymore. This is what occurs during the fall turnover when the lakes surface waters are cooled down by mother nature.

If you don't have a depth sounder that can see the thermocline try to find someone that has and see if they can use their depth sounder to see if they can see the thermocline. The thermoclines also trap lots of sediment in this boundry water and that sediment can reflect sound waves back up to the surface and be seen on the display if you turn the signal strenght of the depth sounder up to high.

Moose:

Does a man-made lake that has flow thru turbines
have thermoclines? Or...does the on-again, off-again
flow pattern keep the water from establishing them?
I do know that the surface water is still very much
hotter than the water at..say, 7 or 8 ft.