Brushpiles and cribs have better fish attracting qualities, normally. But putting anything in a Public lake usually requires some kind of permit and/or permission from the DNR before doing so. (unless your lake is private)
Making sure items are placed deep enough, so as to not create a boating hazard, are usually some of their requirements.
Proper non-polluting materials being another consideration.
Working with a local club (conservation/fishing) usually helps with the process, rather than approaching this situation on your own.
Just some ideas to consider.
Good Luck!