I fish a lake that has some great bass fishing, underwater trees and plenty of vegatation....of course this is only when the lake is full. The lake is used for irrigation and when the lake is drained, although never draned completely, it can get pretty low. which makes it hard to find any structure and hard for me to find bass. I know they are there. just not how to find them. any advise?

drop back to a breakline or the first edge. 

I would think that having lower water would help confine the bass. How deep is the water when it's down?

The lake still is big, there is just no longer any visble structure. The lake is about 20 feet at its deepest. Also I dont have a boat. im fishing on the shore.