I don't know about the legalities of breaching the dam and releasing the water and DNR or state jurisdicition. But, I do know that impounding water inherently creates a legal liability. Many, many dams are poorly maintained. Think about how much water from even a small pond can run down the watershed with a catastropic dam failure. Eight pounds per gallon of water times a million gallons equals a bunch of potential energy. Sometimes it's best to breach the dam and properly repair the it and the outlet works. Is that the case here or are they just getting out of the pond business? It appears to be a beautiful site.