The Grand Union Canal can be fed by local reservoirs, external, such as Drayton and Daventry, and also by pumping water from rivers such as the Great Ouse and Tove.
When reservoir or river levels are low, that supply is limited so the canals have to conserve what water is already in them.
Rigby, who keeps his boat at Culcutt Marina near Daventry, said the locks at Stoke Bruerne were only open between 10:00 and 14:00 BST and queues had formed.
“It’s not desperate but you just need to be aware,” he said.
“I think everyone that I know on the network is on high alert now.
“Northampton Arm’s already closed — you now have to plan and be ready.”
