Hi, we just bought some land in central illinois and want to put in a pond.We have a ravine about 100yards long and 30-40 yard with that looks like it would work great to put a dam in at the end??How can we determin if the soil will hold the water?will all the trees have to be removed or can we leave most in there and let it flood? I just don't know where to start ?I have seen other pond build this way in the area,but don't know if they cleared everything out or just dammed it and let it fill? Any helpful input would be great..THANKS BOB