Environmental Concerns on the Murray
The Murray-Darling Basin rivers are dying. Although climate change has caused average inflows to decline, extractions used for irrigation purposes are still at levels that are damaging to the environment.
However, fundamental problems are ignored by the plan for managing the water resources of the basin that the Murray-Darling Basin Authority (MDBA) has drawn up, and is scheduled to be adopted later this year by the federal parliament.
Politically-driven and unscientific, the plan should be scrapped, and the tasks for saving what is possible to save of the rivers, along with their human communities and ecosystems, should be addressed with a fresh perspective.
Large river flows during the La Nina wet years of 2010 and 2011 have made it possible for irrigators to get their complete water entitlements. In addition, inundations that are desperately needed have been received by floodplain environments.
However, in the basin’s southern part, which accounts for a majority of the inflows, a brutally dry winter is being predicted by forecasters. In those region, the “Big Dry,” which was unprecedented and ran from 1997 through 2009, might be about ready to start again.
In Southern Australia, rainfall is currently on a downward trend. This process has well-established links with increasing global temperatures. A new study is suggesting that as warming continues, the effects will be including more severe and rapid reductions in the amount of rainfall than had been believed previously. In addition, runoff to rivers in the Murray-Darling Basis will decline as well, resulting in lower soil moisture and higher evaporation in the warmer, new climate.
For all of the numerous towns surrounding the Murray-Darling Basin with irrigation being their economic base, they are facing a scary future.
One result of this warming is going to be tropical-style deluges produce floods that are staggering in size. They will fill up water storages, however they will also wreck infrastructure and house as well as destroy crops. However, inflows will still not be sufficient for sustaining the river ecosystems, never mind allow diversions for irrigation for anything resembling our current scale of things.
Recent years climate modelling projects that the median annual rainfall for the Murray-Darling Basin will decline by 5 to 15% by 2060. What is ominous for the rivers is that a 1% decrease in rainfall in the area tends to result in a 3 to 4% decrease in inflows.
However, what is indicated by the new study is that for a certain global temperature increase, the “water cycle” of rainfall and evaporation speeds up much more than what was previously believed. The conclusion is based on ocean evaporation data that comes from salinity readings that thousands of free-floating, automatic buoys collected.
According to Paul Durack, the lead author, the study by the Lawrence Livermore National Laboratory in California and the CSIRO found that the water cycle of the world had accelerated over the last 50 years at a rate twice of what was predicted by climate models.
For each degree of surface warming, it is now thought that rainfall and evaporation rise by approximately 8%.
That isn’t good news for the Murray-Darling Basin, which is drying. The rate in rainfall decreasing might have been underestimated significantly.
Higher evaporation coming from land surfaces will reduce stream flow further as temperatures continue to rise. CSIRO researchers Tim Cown and Wenju Cai, in 2008, came to the conclusion that an increase of 1 degree C in the southern Murray-Darling leads to an approximate reduction of 15% in climatological inflow on an annual basis.
The effect is irrespective of rainfall. It is suggested by Cowan and Cai that an increase in global temperatures of 3 degrees C above current levels, which has been widely forecast for later on in this century, will reduce average flows by approximately 45%.
What will the overall decline in stream flows be? For an increase in temperature of more than 3 degrees C over current levels, it seems plausible that there could be a reduction of 70%. That is an average figure. It is predicted that annual flows will become very irregular in the future, with more severe and longer droughts as well as gigantic floods. This suggests that the future Murray will be an intermittent river.
Study’s Findings Were Ignored
The draft plan of the MDBA’s, which was presented last November, is currently being worked after numerous submissions. However, it completely ignores findings like those from Cowan and Cai. Faced with conflicting demands coming from different state governments, pleadings from environmental NGOs and pressures from various agribusiness groups, the drafters appear to have thought that climate change was yet another complication that they didn’t want to have to face.
In reality, if the science had been considered, the political task of the MDBA would have been impossible. The task is viewed as providing a policy deadlock with sanction, where environmental campaigners are set against large-scale economic interests. This deadlock provides cover, and allows a pro-business federal government an excuse for throwing its hands up in despair – and then go on to shaft not only the environment but working farmers and workers as well.
Accounting for the effects that climate change brings would have blocked the outcome through making the case made by environmentalists unassailable. When revealing the actual scale of all of he damage, pressures made on governments to take strong action against climate change undoubtedly would have intensified.
Asbestos on the Murray
As with many places there is many shelters and buildings that contain asbestos, as well the occsional illegal dumping that goes on. Fresh and Clear have been part of a team that has been helping to conduct asbestos disposal in Perth and they have conducted several jobs along the Murray as contractors.
In recent decades, water extractions have averaged around 13,000 gigalitres per year. It comes as no surprise that when diversions exceed the system’s previous outflow, the Murray fails reaching the sea around 40% of the time, for years at a time sometimes. When flows are reasonable, every year the river flushes around 2 million tonnes of salt to sea. When these flows are not there, the salt stays, which harms agriculture and poisons wetlands.
To counter over-alllocations of irrigation water in the past, the MDBA has been given the responsibility to set levels for extraction right buy-backs. The draft plan makes allowances for the 13,700 gigalitres per year total to be cut by an amount of 2827 gigalitres, that over seven years will be phased out.
Large-scale irrigators, as well as their lobbyists, object and state that level of cuts would result in economic ruin for the river communities.
According to environmentalists, the cuts should be larger, since the figure from the MDBA leaves the rivers with too little water for protecting ecosystems. In June of last year the Australian stated that the findings from a CSIRO report showed that in order to preserve the health of the Murray’s lakes and floodplains. These diversions need to be reduced by 3500 to 4000 gigalitres at least.
A cut of over 4000 gigalitres is needed in order to meet the target set by the MDBA for flushing salt out of the basin.
Towards the ending of the Big Dry, irrigation rights were meaningless, many allocations had been set at zero and storages were close to empty.
The talk among climate scientists increasingly is about how “freak” events like the Big Dry are start to become more the “new normal.” Extreme weather phenomena continue to become more commonplace, and in addition, the extremes are becoming more extreme.
However, it will get a lot worse. The haywire climate of today is a reflection of global warming of around 0.8C since about the middle of the 19th century. It is now believed that warming of 2C is nearly impossible to avoid.
Clearly, large areas in the river environment are doomed. In the centuries to come, sea level increases that emissions to date have locked in will be drowning lakes in South Australia and sending seawater up the Lower Murray for hundreds of kilometres.
With average stream flows reduced drastically further upstream, the struggle will be saving samples that are representative of key ecosystems.
The best hope for irrigators within the basin, lies with new technology that will allow them to use more saline water and a lot less water overall. This equipment could be commercially available soon.