Smoke is rising again over Australia's drought-stricken bush, but this time the flames are from orange trees. For the small farming community of Waikerie, on the banks of Australia's iconic Murray River in the region once known as the country's fruit bowl, bonfires of dead or dying citrus trees are an increasingly common sight this year. Weighed down by debt and two years of severe drought, farmers have 'turned off' many of their citrus trees, depriving them of increasingly expensive irrigated water and leaving them to die instead. Instead of selling oranges at a loss, farmers are burning their trees to stop them becoming a bushfire hazard. 'The region has never looked more down the barrel,' said local farmer Kent Andrew, chairman of a citrus growers' association of South Australia. 'The bottom line is equity for water.' Water is a sensitive issue here and one that elicits strong emotions. This area, the Riverland of South Australia, takes its name from the river that winds through it like a snake. Trees still grow on its green banks and pleasure boats drift along its waters but, after several dry years, both farmers and environmentalists know that all is not well. At an old coaching inn built around 1850 for cattlemen who used to drive their herds down here to the sea, there are photographs of a famous flood half a century ago. It left the inn, located well uphill from the river, with waist-high water in all of its main rooms. But the floods that were part and parcel of the river's ecosystem have not come for many years and the ecosystem itself has begun to change. In the past few months, the Australian government has started to take serious notice, although for many critics it has come far too late. It is spending millions of dollars on a 'buy-back' scheme to repurchase water rights so the resource can be diverted to valued environmental resources, including wetlands of world significance. It has commissioned Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) to undertake a major study to map out exactly where the river's water comes from. Furthermore, it has secured agreement for the river basin, which is spread over four states and stretches far north into tropical Queensland, to eventually be managed on a national basis, hopefully eliminating the frequent, harmful squabbles between state governments over water. The Murray-Darling Basin Commission has been given the task of preparing a management plan. Its head, Wendy Craik, said the plan should be ready by 2011 but admitted it would not be easy reconciling the competing interests. 'There was never really a shortage before. There was a big focus on development,' she said. 'The basin plan is going to be a real challenge.' The Murray flows for approximately 2,500km and winds through Waikerie on its way to the sea. Although much shorter than the Amazon, Nile, Mississippi or Yangtze, it is still Australia's largest river. Its catchment area covers roughly one-seventh of the continent's surface area and produces 40 per cent of the country's agricultural output. But, in recent years, Australia has begun to pay the price for years of overuse of the river's limited resources. Its main tributary, the Darling, flows only intermittently. In South Australia, where more than 1 million people in the city of Adelaide depend on the Murray for drinking water, the planting of water-intensive crops like cotton and rice on tributaries in other states is liable to work the most mild-mannered up into a near frenzy. Waikerie's orange trees will not be easy to replace. It takes around seven years to grow an orange tree and 10 before it will turn in a profit. This tight-knit community of around 4,500 people is one of a series of small towns along this part of the river. Like many of its neighbours, it receives little rainfall and its agricultural sector is largely dependent on irrigated water. Neighbouring Berri gave its name to one of the country's best-known fruit juice brands. In the last century, particularly after the second world war, Greek and Italian immigrants to Australia realised that the region's climate was similar to the one they had left behind in the Mediterranean. They reasoned that the same crops they grew in Europe might do well there. The area turned into a major grape producer, accounting for a substantial proportion of Australia's wine production, as well as citrus fruits, almonds, avocados and a variety of crops that like a warm, dry climate. Signs written in Greek can still occasionally be seen. But a little water is not the same as none. As Australia slowly woke up to what was happening to its greatest river, farmers' allocations were slashed. Many now receive 6 per cent of their nominal allocation, which is too little for some crops. They can buy in or 'lease' water in the still very young and somewhat chaotic water market - which features an official 'water exchange' operating something like a stock exchange. With the current price at around A$550 (HK$3,470) a megalitre, however, people are having to take hard decisions. Local farmers say millions of dollars have already been spent keeping plants alive and many are deeply in debt. Property prices are down, young people have little reason to stay on the land and banks are increasingly reluctant to dole out more credit. Farmers whose families have held their properties for two to three generations increasingly wonder if the time has come to sell up. 'I think in the last year 12 per cent of the citrus in the Riverland was switched off,' said Tom Martin, vice-chairman of the South Australian Murray Irrigators, a group representing 3,000 water users across the state. 'All of our profits are being spent on leases and interest.' Around Waikerie, locals can point out the sharp line on the riverbank that indicates how high it used to flow. Scientists say it needs a radical rethink if Australia is to avoid the kind of environmental disasters that have occurred in the Aral Sea in Central Asia or the marshes of southern Iraq. 'The difficulty is that water allocation was only ever based on volume,' said Justin Brookes, an associate professor at the University of Adelaide and expert on water conservation. 'Even though we knew there was not that much water available, we still used it at the same rate. We really don't experience floods like we used to.' The floods were a critical part of the river's ecosystem, sustaining the red gum trees and others on its banks. The river would flood, replenishing the water table in the land around it, then sink again. It was a natural, periodic cycle which cultivators found a major nuisance and tried to halt. Down river, the mouth of the Murray has seen some dramatic changes, which environmentalists fear could be a taste of things to come if the changes being undertaken are not properly and forcefully implemented. Near its mouth is a system of lakes and wetlands known as the Coorong, which was once a major refuge for migratory birds, many of them seasonal visitors from Asia. It is an estuarine environment and, as the river's flow has diminished, parts of it have become more and more salty, with salinity levels five times that of sea water in some places. Some have compared it to the Dead Sea. The plant life, which ultimately nourished the ecosystem, has been dying off, resulting in bird numbers dropping off catastrophically. According to one audit, 8,000 hoary-headed grebe were recorded in 2000 but, by 2005, there were 2,600. Historically, there are thought to have been tens of thousands. The site is recognised as being of world significance, like many in the Murray's catchment area. Environmentalists are deeply troubled. Australia is a very dry continent and its parched interior is full of dry riverbeds, which occasionally flow after heavy rains. While the Murray remains very broad and rich in wildlife around Waikerie, that could change. The answer, according to one environmentalist, may be a move away from the traditional crops which have been planted in its basin and away from exports of water-intensive varieties like citrus fruit. Instead, said Paul Sinclair of the Australian Conservation Foundation, there could be new industries including some dependent on managing the river's ecosystem. Before it was settled by Europeans, the Murray sustained one of Australia's most dense populations of Aborigines, who lived with the river and respected it. With climate change predicted to hit hard, hands may be forced. 'Australia is extremely vulnerable, probably more so than most countries on the planet, to climate change,' said Dr Sinclair. 'Rivers like the Murray are basically a river running through a semi-arid landscape. It is a river in a desert.'