Local legend has it that there is a city (not a village - or even a town - but a city!) submerged beneath the waters; this was apparently flooded when an angel disguised as a beggar was repeatedly refused hospitality by all of the residents except for one who had helped the beggar (and who conveniently lived on higher ground) who was spared.
"Semerwater rise, Semerwater sink - and bury the town all save the house where they gave me meat and drink." - so goes the verse of Sir William Watson's Balled of Semerwater. Whatever the origins of the story this is Yorkshire's very own "Atlantis" legend!