I would take it down. It appears that dirt from the dam has significantly changed the depth of its roots. It will probably die anyway from suffocation or lose a lot of its vigor on the dam side. Here are some pics of me enjoying some of my clearing work. Cleared about 150' of shoreline on the west side, got about 50' to go and got to cut out the mangled trees the old owner butchered with 5' tall resprouting stumps around the rest while leaving brush and healthy trees for the wildlife.
My wife fishing for the first time and mom watching 11/8/08:
Me fishing 11/8/08 while enjoying the fall colors and weather:
