The Millennium Drought, from 2001 to 2009, devastated communities, industries and the environment, which all rely on a healthy River Murray to prosper.
A combination of low rainfall and the lowest inflows into the river in recorded history meant flows over the border into South Australia virtually ceased, with unprecedented impacts.
Adelaide’s water supply was threatened, and pipelines had to be built to deliver drinking water to the Lower Lakes communities and sustain valuable horticultural industries.
Supplies to the nearly 4000 South Australian irrigators that get their water from the River Murray were severely restricted, putting pressure on agricultural and horticultural industries and regional communities.
33 wetlands were temporarily disconnected to help save water, risking long-term damage to the ecosystem.
The Lower Lakes began to dry up, exposing acidic soils, and the Murray Mouth closed, forcing around-the-clock dredging to ensure salt and other pollutants could be flushed out of the river system.
Parts of the Coorong became too salty for many native plants and animals to survive, becoming five times saltier than the sea.
At the peak of the drought:
- flows across the South Australian border fell to just 960 GL per year
- Adelaide was placed on Level 3 water restrictions
- irrigators started 2008-09 and 2009-2010 with the lowest starting allocation on record – just 2 per cent
- low water levels caused riverbank collapse along the river below Lock 1
- lakes Alexandrina and Albert reached their lowest point in a thousand years with the water level in Lake Alexandrina plunging to 1.1 metres below sea level in April 2009
- 20,000 hectares of acid sulfate soils were exposed in the Lower Lakes region
- salinity reached record levels, damaging ecosystems and threatening water supplies for people and livestock
- the Murray Mouth almost closed in 2002, triggering the start of round-the-clock dredging for the next eight years
- Aboriginal communities suffered the exposure of ancient burial grounds.
Dr Luke Mosley of the Environmental Protection Agency discusses water quality risks in the lower River Murray and lakes associated with the extreme drought.
Much work has been done to help drought recovery and build resilience into the river system so it is better able to cope with future droughts, including working on the Basin Plan.
There are many signs of improvement, but we are just at the start of the journey to return the river to health and a sustained effort is needed to ensure we have a healthy, working river for the future.