Discharges into Kaikorai Stream, in Dunedin, are the first to be investigated as the Otago Regional Council looks at stormwater discharges into Otago's streams, lakes and rivers.
Kaikorai Stream was the first to be investigated because of ongoing concerns about its poor water quality, council resource management director Selva Selvarajah said.
"There has been an inference that undetected stormwater discharges have caused poor water quality."
Throughout the region there were many pipes, both private and local authority-owned, that discharged into freshwater bodies.
In the past, the regional council had concentrated on stormwater discharges to the coastal marine area.
"We have never given attention to freshwater bodies. The presumption was they were meeting permitted-activity conditions."
For the Kaikorai Stream, the first stage of the investigation involved discovering and mapping all outlet pipes and recording their discharges. Of the 278 pipes inspected, 78 were discharging stormwater, 27 of them at more than one litre a second.
The second phase of the investigation would look at the effects of the discharges.
A similar project would probably be undertaken with the Water of Leith and Lindsay Creek.
