Mike,
With costs being equal, thats a tough call.
In addition to the comments you've received already, I'll throw out my thoughts. If the conservation lake was built with government funding, are there any restrictions attached to the purchase of the property and/or lake? Who made the call that the dam was in excellent shape? With the impoundment being 30+ years old, is there some maintenance work that you may be looking at in the near future?
On the flip side, a new project, designed from scratch with your goals in mind "could" be a fun project however I would certainly do the necessary homework to determine what obstacles you may encounter. One possible obstacle that has been touched on in the past conerns local government agencies, i.e. ACOE permitting.
DD1 just posted and is obviously more knowledgeable with your situation. Never ran across problems with mineral rights in my area but I'm sure that would be a concern to you.
Thanks for posting and good luck with your decision. Please keep the board updated.
