I remember last year it was torrential rain and we were setting high on Dartmoor. I remember opening a tunnel and it was literally a full tube of running water, gushing like a spring and my mate said you are never going to set that? I did and over night the rain had subsided, the moles then rush in to clear the tunnels. In the morning I had a mole in that trap and when I lifted it to reset it the tube was clear and reasonably dry!