When Carla Mason and her children visited North Mole on Friday afternoon, they found rust-coloured water surging out of a pipe and into the river.

The family sometimes fishes at the mole, and it was an unwelcome sight.

Nobody else was there and Miss Mason took a video. “It was gross really,” she said. “I’m concerned about my fishing.”

Castlecliff photographer and naturalist Lynne Douglas found the same thing last year. She watched rusty orange water gushing out of a stormwater outfall and into a clear river on May 5.

At the time, Whanganui District Council senior stormwater engineer Kritzo Venter didn’t know where the water had come from. He said it could have come into the stormwater system from any of a thousand sources, some of them natural.