Badgers have been blamed for the collapse of a 40-metre stretch of embankment on the Llangollen Canal.
Boats can travel between Llangollen and Nantwich in Cheshire
The animals are thought to have burrowed too close to the canal, causing 10 million gallons of water to flood onto fields.
A section of the waterway has been closed since the breach near Bettisfield on the Wales-England border on 7 December.
Canal holiday companies have said they are worried about losing business.
British Waterways staff managed to stem the flow of water on the night the bank broke but the level had already dropped by a foot.
They have worked around the clock since to rebuild the sides but repairs are not expected to be finished until Easter 2005.
The total cost has been estimated at £500,000.
Visitors take holidays on the waterway, which is part of the Shropshire Union Canal, throughout the winter months.
Canal boat operator Colin Hill is advising customers to cut trips short
Now boating holiday operators have said they fear having to turn people away because of the canal's closure.
Colin Hill, who runs Maestermyn Canalholders, said: "We have taken quite a few bookings and advertised the fact that we can have these holidays and short breaks during the winter months.
"Now we are in the throes of getting in touch with customers and telling them they would have to have a short break instead of a week's holiday.
"We don't think it is fair for them to have a short trip in a week."
The 47-mile canal flows between Nantwich in Cheshire to Llangollen and is due to celebrate its bicentenary in 2005.
The popularity of the area was boosted in the summer of 2004 when Hollywood stars Harrison Ford and Calista Flockhart took a trip up the canal on a narrowboat.