Lower Murray Water is a convening agency within the region for Blue Green Algae monitoring and reporting. The monitoring of the Murray River for BGA is undertaken by staff from the New South Wales Department of Environment and Water and is reported back through the Sunraysia Regional Algal Coordination Committee. LMW also monitors the raw water entering our water treatment plants.
Natural Occurence of blue green algae in the environment
Blue-green algae (cyanobacteria) are an important, naturally occurring component of aquatic ecosystems and provide the primary food source to more complex organisms in the food chain.
In response to favourable environmental conditions, they may undergo spectacular population explosions, called blooms, which may be toxic to a wide range of aquatic and terrestrial organisms.
Blooms occurred under natural conditions, prior to the development of inland Australia and to river regulation. In 1830, explorer Charles Sturt noted that the waters of the Darling River had a taste of vegetable decay as well as a slight tinge of green. This note may well have been describing a blue-green algal bloom.
Regional Incidence of blue green algae blooms
Over the past 25 years, toxic and non-toxic algal blooms within water storages, weir pools and the inland rivers network of New South Wales, Victoria and South Australia, have been reported with increasing regularity.
In the Sunraysia Region of New South Wales and Victoria, significant algae blooms have been identified and monitored in recent years.
In January 1990, an extensive bloom of Microcystis aeruginosa covered an estimated 400 hectares of Lake Victoria requiring the isolation of the Lake which would otherwise have supplemented the water entitlement to South Australia.
In November 1991, high counts of Anabaena spp. were identified throughout the Mildura weir pool, which forced the cessation of town water supply to Gol Gol (population 600) and threatened the municipal supply to Mildura (population 22,000).
Typically, blue-green algae blooms affect many of the tributaries, backwaters and slower moving reaches of the River Murray during the warmer months from November to May.
During 2004/05 potentially toxic algae blooms were identified and monitored in the Darling River between Burtundy and Wentworth, and in many backwaters of the River Murray during summer and winter months.
Identifying algal blooms
