Adding rocks isn’t practical. You need a lot of them or some really big boulders to make a difference
I sink trees and brush along with some pvc/irrigation tubing trees
The best brush piles will produce year round, but I also sink brush piles with prespawn, post spawn, winter, and summer in mind
In general, I like like 8-20 feet of water. Placing a brush pile too deep and you risk it being below the thermocline in the summer. Place one too shallow, and it becomes useless in drought conditions.
My usual process
Find an area that really sticks out from the rest of the lake.
For example, there is a small lake I fish where all the bank is either grass or clay dirt. There is one bank that is white limestone rock and gravel. That bank also happens to be the closest to deep water About 50 yards off that bank there is a sharp
Channel swing that comes close the bank. The channel swing makes a “v” with the point of the “v” facing the bank. There are humps on both sides of the “v” The brush pile sunk along that drop off into the “v” is very good
Find dramatic change in contours. There’s this expansive flat 4ft deep for about 200 yards, but in the middle of that samie samie flat is a cut that is about 20 yards wide and 8-10ft deep. Brush pile there is good
Find the deepest spot closest to the bank. Drop brush along that slope
Brush pile adjacent to the deepest dock
Brush pile adjacent to the drain or water intake/out take, adjacent to a fresh water spring, water fall
In the summer, take note of where you see the deepest aquatic vegetation (lily pads, grass, etc). Place a brush pile adjacent to this area. (This area is usually a hump or underwater point)