A similarly mad plan would be draining it. Create a bypass and then pump out the water from the deep pockets and see what's in there. I imagine there's some p

A similarly mad plan would be draining it. Create a bypass and then pump out the water from the deep pockets and see what's in there. I imagine there's some political challenges to that, but from an engineering perspective it's old hat. High likelihood of being sued and shut down by the local government, but low likelihood of anyone dying.