I would contact your local Department of Natural Resources. Seeing as how you have a river designation leading in and out of the property and that there is marsh/swamp as well on that topo map. I am betting you will need permits for sure. Also the Gravel labeling is a concern to me but I am not a pond builder that should be designating a surface feature.

Coming from Wisconsin myself(Originally), you have to realize we had a lot of glacial deposits in that area over the history of the world so the soil can change semi rapidly. Sand and loam to gravel and large boulders. All things to consider.

I wish you luck in your pursuit and hopefully some of the other guys will chime in on what they think as well. It still looks like a nice piece of property.