Unless they planned to destroy the dam for other reasons, I don't see why somebody wasn't capable of cutting the tree up and removing it without destroying the neighborhood dam.
Should have had the guys that implode buildings come and blow this up. Leave the concrete , it would have made a great place for fish habitat. The only problem is the rebar,
There are so many reason to take down the damns on this river. The natural habitat will be restored as fish can swim upstream from the Delaware River. Water will be cleaner as flow increases. Area behind damn will no longer flood as there is a place for the water to go. Repairs necessary to have damn operate properly (which serves no present purpose) would cost too much. Finally, since water flow increases, the river will no longer form a lake upstream which always kept that water too warm for the native habitat.