Water quality monitoring at rivers and lakes in Otago

Cyanobacteria at a reduced level in Lake Hayes

This week’s water quality testing from Lake Hayes shows that cyanobacteria in the Lake has reduced to a suitable level for contact recreation. However, swim warning signage will remain in place for at least another week. This is in-line with government water quality guidelines for recreational swimming whereby following a cyanobacteria warning, biovolumes have to return to a safe level for two consecutive weeks before a waterway is deemed safe for swimming. The results from next week’s testing will be available on 21 March.

Swim warning removed from Frankton Bay – Lake Wakatipu

Water quality samples taken from Frankton Bay at Lake Wakatipu have shown significantly reduced levels of the bacteria E. coli. Water sampling on Monday 12 March showed E.coli levels at 3 E. coli/100 ml. This has reduced from last week’s elevated bacteria levels which indicated 1414 E. coli/100 ml. The Lake is once again suitable for swimming and warning signage was removed yesterday.

Swim warning removed from Manuherikia River

Water quality samples taken from Manuherikia River at Shaky Bridge have shown reduced levels of E. coli. Water sampling on Monday 12 March showed E. coli levels at 122 E. coli/100 ml. This has reduced from last week’s bacteria levels which indicated 866 E. coli/100 ml. Signage advising against swimming was removed yesterday.

Government water quality guidelines for recreational swimming areas are that those with less than 260 E. coli/100 ml should be safe, whereas water with more than 550 E. coli/100 ml indicates a potential health risk. 

Additional rivers and estuaries

Many rivers and estuaries in the Otago region are now showing reduced levels of bacteria this week. This includes Macandrew Bay in Dunedin, which last week returned an elevated level of the bacteria Enterococci due to rainfall. With calmer weather this week, the bacteria has reduced to a minimal level and is suitable for swimming. 

Please check the LAWA’s ‘Can I Swim Here’ website regularly to stay informed about water quality levels around the region: www.lawa.org.nz/swim