General News
14 March, 2025
Ideal conditions see algae bloom
Blue-green algae warnings across five local water storages are due to recent hot and dry conditions, according to Goulburn-Murray Water (GMW).
While it’s common for GMW storages to experience high levels of blue-green algae in late summer and early Autumn. GMW water quality manager Greg Smith said conditions have been “particularly conducive” this year.
“[Blue-green] algae thrive when there is plenty of sunlight, little wind and temperatures are warm,” he said.
This has been exacerbated by a number of factors including hot weather and lack of cloud cover in recent months.
“Dry weather and high irrigation demand have also seen water levels in many of GMW’s Loddon storages fall. When there is less water in storages, the water tends to be warmer, which can also support blue-green algae growth,” Mr Smith said.
Due to the size of GMW storages they are particularly challenged by blue-green algae. Methods to reduce algae levels trialed to relative success in small water bodies aren’t yet feasible at the larger scale.
However, Mr Smith said GMW still take various steps to manage their water bodies including regularly testing blue-green algae levels.
“This is done using a combination of water samples that are collected and sent to a laboratory for analysis, visual inspections by storage staff, and monitoring of chlorophyll levels via satellite imagery,” he said.
Also, because blue-green algae tends to gather near the surface, GMW take steps to reduce the risk of it spreading down stream from impacted storages.
“When releasing water from storages with high levels of blue-green algae, GMW looks to do so using outlets and valves that are deep beneath the waterline,” Mr Smith said.
GMW issues warnings when blue-green algae levels become harmful to humans and animals, such as those currently in place for Carin Curran Reservoir, Laanecoorie Reservoir, Newlyn Reservoir, Tullaroop Reservoir, and Hepburns Lagoon.
“People who come into contact with water contaminated by blue-green algae can often become quite ill, so it is crucial people heed the warnings that are in place,” Mr Smith said.
People can stay up to date with the latest alerts via the GMW website: www.gmwater.com.au/bga