Scott, great visual horror story. In Oregon, near the Idaho border is a lake called Owyhee Resevoir. It has a real one of these things. When the resevoir is full, the spillway is fed by a big hole, just like a big bathtub drain, large enough to swallow a pleasure craft. Local urban legend has it that two fishermen lost track of where they were drifting and just barely got their motor started before being sucked into the drain which empties into the river some 300 feet below. A scary prospect, indeed.