2009 March: Lake Hume (Vic/NSW). Blue Green Algal Bloom

Cyanobacterial Bloom Management Current and Future

Options Abstracts from the meeting held 12 & 13 August, 2009, Parramatta, NSW

The Victorian response to the 2009 Murray River algal bloom

Victorian water managers are required by the government to monitor their storages for blue green algae (BGA) and prepare incident response plans to enact when algae levels reach certain (human health) triggers. Goulburn-Murray Water (G-MW) has also been nominated to coordinate BGA preparedness and response across the G-MW region of northern Victoria.

The Murray Region Algal Coordinating Committee (MRACC) is the cross-border body that prepares for and coordinates response to algal blooms along the Murray River, from the headwaters to the confluence with the Murrumbidgee River. The MRACC members include representatives from G-MW, MDBA, and water, health and local government agencies from both NSW and Victoria. The Sunraysia RACC performs a similar role from the Murrumbidgee confluence to the South Australia border.

In early March 2009 Lake Hume developed high levels of BGA, leading to public health warnings to avoid contact with the raw water. A week later high BGA levels were confirmed in Lake Mulwala (Yarrawonga Weir) and a public alert was issued by G-MW on 13 March 2009. In the following weeks high BGA levels were also detected in the Murray River between Lake Hume and Torrumbarry Weir and later downstream as far as Robinvale (Euston Weir). The initial alert for the Murray River was issued on 26 March 2009 after a teleconference of key MRACC members including GMW.

The alert was extended to Tooleybuc, downstream of Swan Hill, on 6 April 2009. Blue green algae levels started to decline in late April 2009 and by 15 May 2009 had all fallen below high alert. The MRACC convened via teleconference and the response included monitoring plans, media communication, signage, town supplies, aerial surveillance and toxin testing.

G-MW coordinated the Victorian response. This included contacting local councils and Parks Victoria to advise them of the need for signage at recreational areas and liaison with urban water authorities.

The main method of communicating with the public was media releases and subsequent media interviews combined with signage advising against contact with and use of the water. Media releases were issued weekly. Information was also available via websites and telephone information services in both states. No reports of adverse health effects due to the bloom have been received despite the continued use of the river and lakes by many people. The three main species of blue green algae detected can be toxic through contact (skin irritation) and ingestion.