I visited last week and someone had torn down part of the dam. The pond had drained at least a foot. But they have repaired it and the pond is full again! I also discovered a smaller dam just about 30 feet below the first one where the creek drained into some pipes. In the last few photos you can see where they've repaired it with fresh vegetation and mud. There were human footprints on the dam and it was busted in the center.
Water oak? Lots of definite water oak in area, but this one had much larger different shaped leaves.