There was an interesting report on a BBC Radio 4 program Open Country this morning, 14/8/2010, with contributions from geologist Mike Simms and cave diver Pat Cronin.  If you weren't up early enough to catch it try the BBC iplayer.

http://www.bbc.co.uk/iplayer/episode/b00tcfhl/Open_Country_Western_Irish_Lake_District/

Nice programme -- particularly interesting to hear about the ill-fated Cong Canal  :