Lake where the strange drownings are occurring in episode 1x03 "Dead in the Water".
Carter and Stark go to talk to Dr. Todd while he is fishing on the lake in episode 2x02 "Try, Try Again".
Liv wakes up inside a body bag on the beach after the ill-fated boat party in pilot episode.
A young girl disappears while her family is camping by the lakeside in episode 1x04 "Conduit".
Source: XF Marks the Spot
Shelby visits the lake to pray to god about the strange events on the island in episode 2x03 "Unclean".