The health of the River Murray is critical to the current and future wellbeing of South Australia. The Murray provides Adelaide with approximately 40% of its drinking water and its water is piped south to Keith and west to the Eyre Peninsula. The river also supports diverse aquatic ecosystems, including RAMSAR wetlands, provides much of the state's irrigation and stock water, and is used for swimming, water skiing and other recreation activities.
There are many pollution sources along the river's length, such as stormwater runoff, shack septic tanks, and river vessel discharges. However, the major source of pollution is the return of irrigation drainage from the Lower Murray Irrigated Reclaimed Areas (LMRIA). This is wastewater coming from flood irrigation of dairy farm pasture. It contains high nutrient, organic and pathogen loads from cattle faeces washed off the pastures, and salt from the shallow groundwater.
The LMRIA consists of 27 reclaimed irrigation areas between Mannum and Lake Alexandrina. Up to about 180 gigalitres (GL) of water per year is diverted to these pastures for flood irrigation and approximately 80 GL per year of polluted drainage water is returned to the river.
As a result of these and other pollution sources, pathogen and dissolved nutrient concentrations increase significantly downstream of Mannum and exceed water quality guidelines. The nutrients discharged into the river are likely to contribute to algal blooms in the river and the Lower Lakes. The pathogens compromise water supplies taken from the river, including for several townships that have minimal treatment facilities.
A $35 million restructuring project has been carried out in the Lower Murray Irrigation Areas. This project was jointly funded by irrigators and the state government and will improve water efficiency and reduce pollution of the river. Restructuring included infrastructure upgrades such as water metering, laser levelling of paddocks, and installation of runoff water reuse systems.
The EPA's objective was that there would be no return of excess flood irrigation runoff to the Murray after June 2008.
Other EPA strategies included:
- audits of milking shed effluent systems
- water quality monitoring programs
- audits of river vessel wastewater system for grey and black water discharge
- audits of marinas and slipways.
‘Sand dumping’ is the practice of dumping beach or other sand on a river bank to create an artificial beach or embankment. Sand is often dumped when unstable mud or rocks on the river bank are exposed.
Unfortunately sand dumping can harm the environment and create safety hazards (eg riverbank collapse). However, there are alternatives for stabilising your river bank that are far less harmful and dangerous.
Why is sand dumping not allowed?
During periods of drought and prolonged low river levels, landholders along the River Murray dump more sand, usually to improve their access to the river for recreation (eg boating and water-skiing). The river is already under great stress due to low flows. Sand washed into the river can:
- reduce water quality, increase river turbidity and lead to in-filling of creek pools
- smother natural sediments that support native plants and animals
- restrict access to river water for navigation and create uncharted sandbars
- block irrigation channels
- damage pumping equipment for mains water supply intakes
- increase the need for dredging
- increase the risk of cracking and slumping due to the creation of added weight on banks already under stress.
Sand removal can also have environmental and cultural impacts including:
- damage to Aboriginal cultural heritage sites
- the spreading of weeds (such as branched broomrape, a serious pest of crops and pastures), pests and other contaminants.
What are the reasons for dumping sand?
- I’ve always had a beach for my boat access.
- It’s hard to walk in the mud.
- I want to extend my grass down to the water line.
- I need to cover rocks and branches that are now exposed.
The EPA understands that it can be difficult to access the river, particularly where there is an unstable bank, mud or rocks.
However, a short-term solution of sand or other sediment will quickly wash away when the river returns to normal. Once the sand is covered with grass and mixes with the existing bank, removal will be difficult and the impact will be quickly forgotten.
|Sand deposited to create a beach or
mobilised to block the adjoining channel
|Sand that will wash into the river|
The EPA has observed instances where dumped sand has been sucked into water pumping infrastructure nearby, leading to costly repairs and damaging relations between landholders. Aerial views of the River Murray show how large amounts of sand have washed away from shack areas to create new sandbars, creating risks for boats and danger for others enjoying the river.
Is sand dumping illegal?
Dumping sand is always illegal and very harmful while the river is low.
Depositing sand into the riverbed contravenes Section 34(2) of the Environment Protection Act 1993, in this instance through a breach of Clause 11 of the Environment Protection (Water Quality) Policy 2015 (the Policy), which states:
A person must not discharge a class 2 pollutant into any waters.
Soil, clay, gravel and sand are class 2 pollutants listed under Schedule 3 of the Policy. Also, according to clause 3(2) of the Policy, the discharge of waste or a pollutant into a watercourse that is temporarily dry will be regarded as the discharge of the waste or pollutant into waters.
Similarly, dumping sand into the river is also a breach under the River Murray Act 2004.
What are the authorities doing about sand dumping?
The EPA, along with the Department of Environment, Water and Natural Resources; Natural Resource Management Boards and local councils are running an education and awareness campaign on sand dumping.
Where sand is found to be causing a problem, the owner may be asked to remove the sand and deposit it in a place from which it is unlikely to enter any waters (including by processes such as seepage or infiltration, or carriage by wind, rain or stormwater). Penalties may also apply, such as an expiation notice or an Environment Protection Order.
In extreme cases, where pollution of the River Murray is regarded as intentional or reckless, penalties of up to $30,000 for an individual and $120,000 for a company may apply.
How can I stabilise my riverbank frontage if I can’t use sand?
Geotech sheets, shadecloth, temporary plastic floor tiles or sand stabilisation products can be secured over any exposed mud to allow access to boats and the water. However, these must only be used on a daily, as-needed basis and removed after use.
All proposed permanent works, including cutting, filling, excavating, permanently positioned geotech 'pillow' bags, dredging or any construction on the river edge will require a Development Application. Please contact your local council directly, or visit the links below.
Alternative materials and methods for stabilising your riverbank include:
- a retaining wall constructed of stone, timber or similar
- bank restructure using sand bags or similar (see pictures below)
- secured synthetic turf or geotech fabrics (which can support sodding or seeding of fast growing vegetation).
These materials are more stable and less vulnerable to erosion. Shadecloth and carpet are not recommended as they will perish and break down with long-term immersion and sun exposure. Pontoons and jetties are being actively discouraged, with few new structures being granted permission to be built.
Synthetic materials must be firmly secured to the bank with pegs/staples, sand bags or other appropriate means and must be UV stable and not break down or rot. Many fertiliser bags will break down in sunlight (see pictures below).
|Excellent examples of sand and river edge management|
|Poor examples of sand management: Sand that can still wash into the river when using non-UV stable bags.|
There are many suppliers of geotech materials, plastic flooring and other materials, which can be found through the Yellow Pages or an internet search.
Local councils along the River Murray
- Alexandrina Council
- Berri Barmera Council
- The Coorong District Council
- District Council of Karoonda East Murray
- District Council of Loxton Waikerie
- Mid Murray Council
- The Rural City of Murray Bridge
- District Council of Renmark Paringa
For further information, please contact the EPA on 8204 2004 or 1800 623 445.
- South Australian Murray Darling Natural Resources Management Board
- The Murray-Darling Basin Authority
- Help Save the Murray from Sand brochure.