Nearby, there is a derelict wood and corrugated iron boat shed, which was further damaged during flooding about a year ago.
She believes debris from the shed is on the lake bed.
Yesterday, a large piece of corrugated iron could be seen jutting out of the water.
Huemmer said the whitebaiting season started next Thursday and the area was frequented by scoop net whitebaiters and recreational fishermen.
''A serious cut involving an artery in a fairly isolated area could be lethal,'' she said.
She had contacted both the Otago Regional and Clutha District Councils and had received sympathetic responses, but no concrete action yet, she said.
''At the very least, a clear warning sign should be placed in the area as the potential for injury even more severe than mine is very real.''
Clutha council acting chief executive Jules Witt said the lake bed was the responsibility of the Otago Regional Council.
ORC compliance manager Martin King said by email the council was made aware of the complaint in March, and staff visited the area.
''Debris from the boat shed is not a pollution risk, but we understand Ms Huemmer's concern about the health and safety risk to people in the water.
''Inquiries are ongoing to establish the owner of the boat shed and to have them remove the debris from Lake Waihola.''