Not to state the obvious, but be really careful-if that tote were to be suddenly sucked through the pipe while you were sawing or poking it, the resultant vacuum could pull you down too....it'd be both tragic and embarressing to drown in 3.5 feet of water.
A young boy died just this past summer on a newly built public lake because he fell too close to an outlet pipe. Tragic indeed.
I'd go with the idea of stretching a chain or rope across the pond to pull it loose with the 4-wheeler. It sounds, and will look, ridiculous, but I think that'd be your best bet.
