I live in southern IN and I sometimes fish an old quarry/gravel plant that is around 20 acres in size.  It is approximately a long oval and has mostly bluff banks with plenty of wood cover but NO vegetation.  The bottom is clay and/or sand with chunks of the quarry stone sparsely scattered about.  The water is very muddy.  The lake is connected to the White River by a small channel around 1-3 feet deep, 6-10 feet wide and about 20 yards long.  I catch some pretty nice bass here in the spring and fall, but it gets really tough in the heat of summer as the water approaches and surpasses 80 degrees.  I have tried fishing deep and shallow, slow and fast.  I use jigs, deep and shallow cranks, t-rigs, c-rigs, shaky head, Chatterbait, spinnerbait, topwaters, etc.  In short, the whole tackle box at all depths, sizes and speeds.  My question is this -  As the water warms up, are the bass moving back out into the current?  Is that why they're so elusive?

Cool water.

Oxygen.

Current.

This is where you will find them.

And once you find them you still have to catch them. Once they stage like that they are hard to catch. In NC I have know them to stay like that for weeks.

Try some electroshock therapy on them. ;D

i fish a similar area, your bass have been pressured with all those baits you listed then use baits that they never seen before. small channel around 1-3 feet deep, I caught 5lb bass in channels that deep. Fish the small channel.

Have you tried fishing at night?

I live in southern IN and I sometimes fish an old quarry/gravel plant that is around 20 acres in size. It is approximately a long oval and has mostly bluff banks with plenty of wood cover but NO vegetation. The bottom is clay and/or sand with chunks of the quarry stone sparsely scattered about. The water is very muddy. The lake is connected to the White River by a small channel around 1-3 feet deep, 6-10 feet wide and about 20 yards long. I catch some pretty nice bass here in the spring and fall, but it gets really tough in the heat of summer as the water approaches and surpasses 80 degrees. I have tried fishing deep and shallow, slow and fast. I use jigs, deep and shallow cranks, t-rigs, c-rigs, shaky head, Chatterbait, spinnerbait, topwaters, etc. In short, the whole tackle box at all depths, sizes and speeds. My question is this - As the water warms up, are the bass moving back out into the current? Is that why they're so elusive?

IN fish are a tough breed this time of year.  Im a IN boy too.  Stick with it especially early in the morining and late in the evening.  Also if there is any moss or crud anywhere throw a green and white Scum Frog as deep into the junk as you can and drag it across the top.  This is my number one producer when the water is worm.  It seems to work anytime a day.  Also, the first time you get a hit on that from you better be holding your breath cause if you not expecting it you might have an accident.  Good Fishing

PS.  If you are from Linton have you ever met MINNER FISH??

Ceph -

I have noticed a significant increase in the population of our lake so perhaps?

if there is any moss or crud anywhere

Sorry.  As I said, there is ZERO vegetation

PS. If you are from Linton have you ever met MINNER FISH??

Oh, yes.  He lives about 1/4 mile from the house in which I was raised.  My parents still live there, so I drive by his bait shop several times a week.

Ceph -

I have noticed a significant increase in the population of our lake so perhaps?

If you get a chance, could you bring some back here for me?