I’m racking my brains trying to remember what this was called. The scanty details I remember - uk tv series, a group of friends have a party in a house the night before it’s due to be flooded as part of a reservoir, maybe in Wales? A murder happens or maybe it’s an accident and it would be covered up by the flood. I thought Andrew Lincoln was in it but I can’t see it on IMDB. Probably late 90’s/ 2010’s