I've done quite a bit of family research in the past for people who have ancestors in the Isle of Ely area, including Littleport, which gets mentioned in the programme. The term Waterman was ubiquitous as an occupation given in the Censuses in this region in the 19thC. The done to death comment about the locals having "webbed feet", alas, too...
Keith
Graham Swift's 1983 novel "Waterland" is a classic of it's kind, too. Steeped in the history of Fenland. Also made into a film with Jeremy Irons starring...who also appeared on WDYTYA many series ago, if I recollect, btw...