About 15 percent of the water taken out of rivers in Victoria is used for industrial and commercial purposes. The manufacturing industry consumed 144 gigalitres (GL) in 2010/11 – 6 percent of the water used in the state. A further 117 GL was consumed by the electricity and gas supply industry.
Metered water use by various industrial/commercial sectors
|Water use 2005/06 (ML)||Water use 2010/11 (ML)||Reduction (ML)||Reduction %|
|Other Latrobe Valley industrial users||25,510||24,229||1,281||5.0%|
Industrial and commercial users have been quite successful in reducing their water use.
Non- residential use has decreased by 24 percent in Melbourne and by 20 percent in regional Victoria since 2005/06. All large water users have been required by government to identify opportunities for water savings and were obliged to implement actions that had a pay-off period of less than 3 years under the EPA’s Environment and Energy Resource Plan (EREP) program. This highly successful program has been discontinued by the Coalition government. Smaller businesses have been encouraged to make savings through the WaterMAP program.
EREP case study – Warrnambool Cheese and Butter Factory
This company, Australia’s fourth largest dairy processor, is saving over $200,000 per year by implementing an EREP. It has saved energy by reducing leaks and synchronising its refrigeration cycles and is saving up to 37 million litres of mains water by substitution and better management. The gains made through EREP have inspired the company to make further investments to save an additional 45 million litres of water and reduce waste.
For this and other EREP case studies, see http://www.epa.vic.gov.au/business-and-industry/lower-your-impact/ereps/…
The EREP program shows how cost effective water savings can be. The UN sponsored CEO Water Mandate has recognised water security as a key risk for business and recommends water stewardship as a mitigating strategy . This international group is leading the way in making sustainable water use a key part of business planning and an integral part of the business supply chain. Victorian industries are under increasing commercial pressure to follow this trend and continue to make savings of the type demonstrated by EREP.
Latrobe Valley power generators
The exceptions to the water savings success of Victorian industry are the power generators and other industrial users in the Latrobe Valley (see Table). Their water use is remarkably constant from year to year and show less variation over time than any other sector.
The brown coal generators are the only water users in Victoria who hold their own private, perpetual bulk entitlements to water – other industrial users have to buy their water from a water corporation. Blue Rock dam on the Tanjil River, a tributary of the Latrobe, was built by government specifically to service the power generators.
The problem for the generators is that they have to use water for cooling and this water has to be of suitable quality. Their high water use is the result of burning brown coal – not only is the generation process very high in carbon dioxide emissions, it’s also a very inefficient user of water. A 1,000MW brown coal plant consumes 13-17GL freshwater per year, depending on the type of cooling system used. A similar size gas plant uses 1-5 GL per year at half the CO2 intensity.
The conclusion is obvious – to address the high water use in the Latrobe Valley, and its impact on the Latrobe River and the Gippsland Lakes, we need to stop burning brown coal for electricity generation. Gas can be a stepping stone in the transition to clean energy– its impacts are much lower than coal, but its extraction causes other problems (see below). A transition to renewable energy will have two great benefits for river systems and for groundwater- it will reduce the direct impacts through reduced water use but even more importantly it will address the biggest threat of all which is climate change. Burning fossil fuels is causing global temperatures to rise and rainfall in Victoria to decline – reducing CO2 emissions is the single best thing we can do for our rivers.
Brown coal mining in Gippsland – multiple impacts on water
Mining for brown coal involves digging a very large open pit that extends well below the water table. Continuous pumping of groundwater is required for the lifetime of the mine to prevent the pit from filling with water. This simple fact is often overlooked when considering the water impacts of the coal industry – if we think about water at all in this context we tend to focus on cooling towers and the direct needs of the power generators.
The fact is that coal mining is having a very significant impact on groundwater in Gippsland. The geology of the area is complex with several aquifers at different depths. The ‘middle’ aquifer on which agricultural users and the Gippsland Lakes depend is being depressurised due to mining activity. This depressurisation is having a dramatic effect on groundwater levels which are showing a steep declining trend over the last 30 years. Even if mining stopped today, it could take centuries for the aquifer to recover. This means that farmers are having to drill deeper and deeper to access water for irrigation and it is possible that instead of freshwater flowing from the aquifer into the Gippsland Lakes, salt water will start seeping in the opposite direction and pollute the aquifer. The area affected is quite large – the bores shown in Figure 1 are at Stratford and at Longford, near Sale, well away from the actual coalmines at Moe, Morwell and Traralgon.
Figure 1. Declining groundwater levels at Stratford (yellow) and Longford (red)
Unfortunately the impacts of coal mining on water resources do not stop at groundwater. Rivers are seriously impacted as well. The effect can be quite literal – the Morwell River has been relocated 6 times to accommodate the Yallourn open cut mine (Link to Latrobe page). The last artificial river bed failed spectacularly in 2012, flooding the mine, and the river is still confined to a pipe. A recent report suggests the collapse was not unexpected , especially as it followed a previous collapse of the Latrobe River itself into the mine in 2007. Both collapses resulted in billions of litres of polluted water being pumped out of the mine and into the Latrobe River, which is already the most polluted river in Victoria. The water ends up in the Gippsland Lakes with unknown consequences.
Bad as this situation is, it’s still not the end of the story. The large scale of the open cut mines means that they trap considerable quantities of rain water which would otherwise find its way into groundwater or rivers. This so-called ‘incidental take’ is unaccounted for and hard to control. The water may be used on site for dust suppression, drilling etc but becomes polluted with the by-products of mining, particularly heavy metals and salts. This creates an effluent that needs to be disposed of. As the mines get bigger there is more and more of it – the Yallourn mine has just received an increased discharge licence from the EPA to pump more water into the Morwell and Latrobe Rivers just because the mine is increasing in size. Instead of the polluter being required to clean up, the river is taking a hit.
In all, brown coal mines remove billions of litres of water from groundwater and rivers and return it in a highly polluted state. The impact on the Ramsar listed Gippsland Lakes and their fringing wetlands have been quite devastating with permanent changes in water quality, and the mines’ groundwater pumping is affecting other users. If the climate change implications of proposed new coal allocations (and therefore new mines) were not enough to stop them, the water impacts should be.
Off-shore oil and gas – a drain on deep aquifers
When oil and gas is extracted from the sea bed, it is accompanied to the surface by large volumes of groundwater. Oil and gas wells in Bass Strait off the Gippsland coast are estimated to bring around 100 gigalitres of water to the surface each year. Because this extraction occurs in offshore waters it is not regulated and does not have to be licensed or accounted for.
The Latrobe Group aquifer is deep under the Latrobe Valley coal mines and runs far out to sea to where the oil and gas deposits are. The aquifer is accessed on land by the coal mines and agribusiness. Pumping is exceeding recharge, and as discussed above, the coal mines are causing aquifer depressurisation. But closer to the coast these impacts are dwarfed by the effects of the offshore drilling. Groundwater levels are dropping consistently by around 1m/year.
Figure 2 Declining groundwater levels in the deep Latrobe Group aquifer
This fall in groundwater levels has the potential to cause coastal subsidence and to allow saltwater pollution of the aquifer. It can also interfere with surface-groundwater interaction where the aquifer reaches the surface in the Strezelecki ranges. For example, baseflows in the Tarra River are 13% lower now than in the 1950s before drilling started. In other words offshore extraction is very bad news for a resource that is potentially thousands of years old and is bring replenished only very slowly at a rate less than the rate of extraction. Oil and gas drilling is just as bad for groundwater in Gippsland as coalmining, providing another reason to transition to renewable energy as quickly as possible.
Coal seam gas – just as ugly
Currently there is no coal seam gas (CSG) extraction in Victoria. However large areas of the Gippsland and Otway Basins are covered by exploration licences and some test bores have been drilled. While the Victorian government has currently imposed a moratorium on fracking to extract CSG, the potential impact on groundwater is very real.
A CSG well requires about 100ML/year of groundwater to release the gas from the coal. Commercial operations could involve several hundred wells so the impact is potentially very large. Groundwater brought to the surface with the coal seam gas may be polluted with chemicals used in the extraction process, as has occurred in Queensland and NSW, or may be salty or naturally contaminated. Since the wells are deep (up to 1000m) they may pass through other aquifers, opening up the possibility of cross-contamination and pollution of aquifers used for drinking and agricultural water, not to mention groundwater dependent ecosystems. And the polluted water could well end up in river systems as is happening on the Condamine-Balonne in Queensland
All in all, if CSG extraction industry develops it could present a major threat to groundwater and river systems on top of all the existing demands. The moratorium currently in place should become permanent.