Testing of Lake Colac, Wye River and Kennett River

Published on 18 December 2019

Colac Otway undertakes testing of Lake Colac, Wye River and Kennett River

Colac Otway Shire Council has taken its water quality testing of Lake Colac, Kennett River and Wye River to the next level and its health protection team is pleased with the results.

Council’s Health Protection Co-ordinator Tony Gullone said in addition to resuming monthly water quality testing in October when warmer weather started encouraging more recreational water use, Council had also undertaken DNA marker testing at Lake Colac, Kennett River and Wye River.  The DNA marker testing indicates whether the source of the bacteria is from human, animal or bird species.

“The tests have indicated no evidence of human E.coli (human faecal contamination) in the three bodies of water which is great news for water users, residents, health and water authorities.

“Tests of samples taken at Lake Colac boat ramp and Meredith Park detected no human or waterfowl E.coli but did detect animal E.coli, which could be from dogs, livestock or other animals in that DNA category.

“This reaffirms our messaging around making sure you pick up after your dog so we reduce any dog faeces washing into the lake from our stormwater system.

“Tests at Kennett River and Wye River also detected no human E.coli however waterfowl (ducks, seagulls, etc) and animal E.coli was detected,” Mr Gullone said.

“But overall, these are positive results because they demonstrate that nearby septic tanks are not overflowing and polluting our waterways.”

Mr Gullone said enterococci levels had generally been below the acceptable organism count* for water use since water testing resumed this season.

However water quality is likely to fluctuate whenever it rains or if water levels in Lake Colac drop over the summer.

“We are publishing results of water testing on our website to keep people informed, but it is important for water users to understand that test results are about a week old by the time we receive them and there are factors which affect the results,” Mr Gullone said.

“Direct sunlight certainly plays an important part in improving the water quality because enterococci is susceptible to sunlight.   

“However Australia and New Zealand Environment and Conservation Council guidelines advise that people should avoid swimming near stormwater, creek or river outlets 24-48 hours after heavy rain.

“Any lake or river which can be contaminated with animal faeces from wildlife and other animals such as dogs will have levels of enterococci, so swimming in Lake Colac and estuaries is at the swimmer's risk.”

*According to the (Australia and New Zealand Environment and Conservation Council) ANZECC guidelines, for primary contact the median enterococci organisms per 100mL over the season should not exceed 35 org/100mL.

Similarly, for secondary contact the median enterococci organisms per 100mL over the season should not exceed 230 org/100mL.

Primary contact is defined as recreation where you are in direct contact with the water, can be fully immersed and could swallow water; this includes water skiing, diving and swimming. 

Secondary contact includes boating.

Visit https://www.colacotway.vic.gov.au/Recreation-tourism/Lakes-and-Waterways for water quality test results and further information.