KEY POINTS:
Despite assistance from Contact Energy in controlling the flow of Otago's powerful Clutha River, searchers have had no luck in finding the teenager who went missing there yesterday.
The 16-year-old Dunedin youth was swept away about 3pm by a strong current about 2km below the Roxburgh dam.
His swimming companion called for help and emergency services were quickly on the scene.
However, searching the riverbanks on foot was too dangerous and a helicopter was called in.
"We're using a helicopter to search the edges, as there is no point in risking the lives of other people," said Senior Sergeant Mike Cook, of Alexandra police.
Several jet boats and a jet ski were also used.
Roxburgh dam operator Contact Energy had been "a great help" by lowering the river flow and level to assist searchers, he told the Otago Daily Times.
The river had carved shelves into the rocks under the water and people could get stuck and it would be difficult to get out, Mr Cook said.
He was considering asking the power company to lower and raise the river today to provide a hydraulic action.
"The change in river flow can sometimes release a person if they have been caught under the ledges."
The search was called off when darkness fell last night but will resume this morning.
- NZPA
