But along with the water comes the fish. And in the fall, when the irrigation networks shut down, thousands of them become stranded. "It's absolutely a recurring problem," said Lesley Peterson, a Calgary biologist with Trout Unlimited Canada. "There's no need to divert water throughout the winter. So as the canals drain … the fish are vulnerable right now to birds and predators and just desiccation [drying out] and freezing."