its actually the salem and Beverly water supply the water is actually really clean it has a healthy population for all kinds of wildlifeI just read a story about how this lake used to be so pure and clean that the ice was shipped overseas to a queen; and that we somehow ruined it with fly ash from a nearby coal combustion waste dumping site - making the waster toxic. The story ended there, but I presume there was some sort of clean-up to make it useful as a reservoir.