Boat users on Lake Wakatipu, Lake Wanaka and Queenstown Lakes rivers are being urged to ''be very careful'', as water levels are dropping by the day.
Yesterday morning, Lake Wakatipu's level was 309.476m above sea level - about 1.7m lower than its level in January, when heavy rain swelled the lake to just below 311.2m.
Records began for lake levels in 1962 and the lowest on record was on September 16, 1966, when it measured 309.295m above sea level.
Queenstown Lakes district harbourmaster Marty Black told the Otago Daily Times yesterday the shrinking lake and lower river levels were throwing up obstacles, requiring caution from boat users.
''Be very careful on the Frankton flats across to the Hilton - there are rocks appearing in the Kelvin Grove ski lane ... certainly, you need to be very careful.''
Mr Black said boat users at Bremner Bay, Beacon Point and west of the Edgewater Resort in Wanaka also needed to take extra care.
''Jet skiers shouldn't go down the Kawarau at the moment ... it's running at 91cumecs ... for the Kawarau, that is bloody low. The Kawarau is very, very bony.''
The Shotover River - which peaked at 180cumecs on January 2 - was now running at only 11cumecs, while the Dart River, which rose to 900cumecs in January, was now at 70cumecs, Mr Black said.
He advised boat users to double their distances from the shore to avoid running aground or hitting rocks.
Meanwhile, Otago Regional Council water resource scientist Matthew Dale said the low level of Lake Wakatipu was not cause for alarm, as there were ''no significant out-takes'' from the lake which would be affected by the level.
''In September last year it was lower, in July 2010 it was lower - almost every year it's lower than that at times.
''It is on its way down [and] if it keeps going like this for a few weeks, we might get to one of the lower ones [levels] on record.''
