Pauline, a Wadi Wadi woman from near Swan Hill, has lived near the Murray River all her life. Her family has swum in the river for generations. “When my grandmother was a girl and she stood in the water, she could see her feet. When my mother was a girl and she got in the water, she could see her waist. When I was a girl, I could see my elbow. Now when my daughter goes in the water, she can hardly see her hand.”
Pauline’s story is a perfect illustration of how water quality has declined in our rivers. She is referring to the increasing amount of sediment in the water which is due to changes in the catchment – basically clearing native vegetation means more sediment gets washed into the river, making the water less clear. Some rivers like our brown Yarra have naturally high levels of very fine sediment due to the topography, but others like the Murray have suffered a major increase. The sediment causes all sorts of problems – it reduces light penetration so inhibits plant growth, it can clog up the gills of fish and the feeding apparatus of invertebrate filter feeders, and once deposited on the river bed can destroy habitat for fish eggs and invertebrates.
Sedimentation is one form of water pollution – there are many others. They include:
• Fertilisers that raise nutrient levels and encourage algal growth
• Other agricultural chemicals including pesticides and herbicides
• Industrial pollution from factories, mines etc which can include heavy metals and other toxicants
• Sewage pollution from septic tanks, faulty connections and unsewered properties
• Faecal pollution from stock grazing on river banks and in waterways
• Salt – both in industrial discharge and as a result of dryland and irrigation induced salinity
• Effluent from waste water treatment plants which generally has raised nutrient and salinity levels
• Stormwater run-off from roads and streets with litter and chemicals
Industrial pollution is theoretically the easiest to identify and control because it is point-source and easily monitored. The EPA is the regulatory body and it has made a significant difference – waste from abattoirs and dye plants no longer runs straight into the nearest river. But there is still a long way to go –contaminated water from mines and industrial plants is still released into river systems. The EPA needs more teeth and a bigger stick to make polluters take responsibility for their discharge and either re-use it or clean it up before releasing it to the environment.
Agricultural pollution is harder to control because it is diffuse and occurs over a broad area. It requires catchment scale action to be effective. Farmers need to adopt agricultural practices that reduce inputs – both fertilisers and chemicals – and reduce runoff into rivers and wetlands. Such an approach saves farmers money as well as protecting river systems. There’s a wealth of research on this topic – it needs to be built into agricultural practice as a duty of care, not an optional extra to be funded by government.
Gippsland Lakes – a no-win situation
The Gippsland Lakes make up the largest estuarine lagoon system in Australia. They are fed by seven rivers and were originally a mainly freshwater environment, separated from the sea by a line of dunes that was only breached at times of flood. The Lakes are internationally recognised for the diversity of their wetlands and vegetation and for their bird life – they are home to over 80 species of waterbirds with 40-50,000 birds in residence. They are also a magnet for tourists, boaters and recreational fishers, and support commercial fishing valued at $2million per year.
All is not well with the Gippsland Lakes. In 1889 a permanent opening to the sea was established at Lakes Entrance which has been continuously dredged ever since. This opening has allowed the Lakes to become much more salty over time with Lake King most affected. At the same time the catchment round the lakes has been cleared for agriculture which has led to the Lakes becoming polluted with nutrients, especially nitrogen and phosphorus, and sediments. These in turn stimulate algal blooms which have had a big impact on the region’s economy. A single algal bloom in summer 2007/08 at the height of the tourist season had a direct economic impact of $18.2 million, and a total cost to the region of $26.2 million and 306 jobs.
A recent study by the EPA shows that the Lakes are caught in a water quality tug-of-war between salinity and nutrients. In dry years, when freshwater inflows are low, nutrient levels drop but salinity increases, especially in Lake Wellington which is normally quite fresh. The higher salt levels kill off vegetation in the fringing wetlands and encourage invasion by marine species.
In wetter years the opposite occurs – inflows are higher so the water is fresher, less salty, but it has a much higher concentration of nutrients, both washed in from the catchments and stirred up from the bottom. These nutrients encourage algal growth which can quickly develop into algal blooms and affect the oxygen content of the water – enriched at the surface, depleted at depth. Bad news for fish and bottom dwellers.
The EPA concludes ‘the ecological health of the Gippsland Lakes is driven by the quality and quantity of catchment inputs, sediments behaviour (ie storage and release of nutrients) and oceanic influence. The Lakes would vastly benefit from a more and better integrated monitoring and reporting program, encompassing sediment and catchment impacts, helping improve the effectiveness of management actions undertaken to protect the Lakes’.
The EPA is right but we need to go further if the Gippsland Lakes are going to retain their values. The water quality guidelines for the Lakes are out of date and don’t reflect the latest scientific knowledge. Catchment programs to control nutrient inputs are at the whim of government priorities and individual farmers – they need to be made a duty of care under the Catchment and Land Protection Act and a condition of farming at all. But there are even more pressing issues -the ‘oceanic influence’ identified by the EPA is currently the opening at Lakes Entrance but in future will be rising sea levels. Climate change poses an inexorable threat to the Lakes with the dune barrier to the sea at Ninety Mile Beach likely to be overwhelmed. Towns like Seaspray and Lakes Entrance could be under water in 50 years. Urgent action to reduce CO2 emissions and decarbonising the economy is the only way to avert this disaster .
Water quality management is complex and spread across a range of regulators and management agencies – the Victorian Waterway Management Strategy takes 3 pages to list the roles and responsibilities of key agencies involved in water quality management and incident response! This has been a problem identified time and again, most clearly in the 2005 Environmental Audit which followed a fish kill in the Goulburn River , and which still hasn’t been fully resolved. The state government’s flagship action plan for the Yarra has ‘identifying the lead agencies for managing water quality’ as its no 1 action , and the VWMS give a timeline of 2015 for ‘clarifying and strengthening’ roles and responsibilities in incident management. It’s time to decide once and for all who is responsible for water quality (the EPA or the CMAs) and give them the funding and tools to manage it. Revising the State Environmental Protection Policy (Waters of Victoria) which provides statewide water quality benchmarks so that it is more comprehensive, strategic and user friendly would be a good start.