Gundar seemed to come to a decision.
"Well, as my old mam used to say, if it looks like a duck and quacks like a duck and walks like a duck, it's probably a duck."
"Very wise," Halt said. "And what exactly do your mother's words of wisdom have to do with this situation?"
Gundar shrugged. "It looks like a channel. It's the right place for a channel. If I were digging one, this is where I'd dig a channel. So. . ."
"So it's probably the channel?" Selethen said.
Gundar grinned at him. "Either that or it's a duck.

Author: John Flanagan