End called on lake's reduced water level

The water level was lowered for engineering works on Scrivener Dam. Although that work is not due to be completed until March, the National Capital Authority has received advice it is safe to return the lake to full-supply level.

Refilling the lake is expected to take six to eight weeks, but could happen overnight in a deluge.

The return to normality is being welcomed by Canberra's rowing fraternity.

''It was a serious annoyance,'' Rowing ACT president David Bagnall said on Friday.

''We've had a couple of years of quite difficult conditions where boats were damaged because there were shallow parts of the lake. We damaged propellers [of safety boats] and scraped boats across rocks. You are more likely to run across rocks that you didn't know were there because the level is half a metre lower. People had to wade through mud and, occasionally, glass.''

Mr Bagnall said Lake Burley Griffin was the best training venue for rowing in Australia.

''So it was very difficult initially when the lake was lower because it happened so suddenly,'' he said.

''However, the NCA and the ACT government have been quite good in modifying the various entry points to the lake for us.''

The work on Scrivener Dam involves the replacement of 120 corroded anchor bolts providing structural support for the flap gates. The gates are opened in floods to regulate the water level of the lake. Bolts on three of the five gates have been replaced.

Given the forecast of a hot, dry summer, refilling the lake may take some time.

''An additional 3500 megalitres of water is required to return the lake to normal levels, so now we just need to wait for rain,'' NCA acting chief executive Andrew Smith said. ''It may take some time for the community to see a noticeable change - 25 millimetres of rain is needed across the entire catchment for 24 hours to increase the lake to normal levels.''