Every fall at a local lake they open the dam up and let the lake drain to where it is 15-20 feet low. Does anyone know what the reasoning for doing this may be? This is a lake that has a lot of algea and weeds in the Summer months due to the surrounding farms and the amount of fertilizers that run into it. I was thinking that they may be trying to kill of the weeds but to me it seems like most of them die off in the winter anyway.

Also how would you approach a lake that is that low? I tried using some faster moving baits and didn't have any luck.

They do the same thing to Mauch Chunk Lake. When the water freezes it protects the dam from having too much pressure against it. It also allows for the snow and water accumulation during ice in.

They usually bring it down around 6 ft, however I believe because of a local drought it is about 4 to 5 feet down now

  The creek bed: Jig head with a trailer I use iether a 3.5 inch brush bug or an *** Beaver Craw, slow

I have found that you need to work the first drop off which most likely is the channel.

I don't know where your lake is but a lot of southern lakes are dropped to get some of the vegetation to die.  Find out who is in charge and give them a call.  They will tell you why they do it.

When the water drops around her the fish move out so move out to ledges and drop offs and go for jigs and trigged plastics.

Most Winter draw downs are done for flood control with the anticipation of heavy spring rains.