ABU DHABI // Farmers face curbs on their use of ground water next year as Abu Dhabi's's dwindling supplies reach a "tipping point".
Agriculture is the largest consumer of ground water and while measures to increase its efficiency are having an effect, more needs to be done, said Razan Al Mubarak, secretary general of the Environment Agency Abu Dhabi.
"We are reaching a tipping point and we really have to act," Ms Al Mubarak told delegates to the International Water Summit.
She said one option was to update an existing law from 2006 that gives the agency the right to oversee ground-water wells. The law was followed by a decree banning the drilling of any new wells.
Ms Al Mubarak said the law could be amended to give the agency authority over how much water users were allowed to take from each well, and to deal with the illegal sale of ground water by well-owners.
"We would like to give the agency more authority to better regulate such incidents," she said.
Laid down in underground aquifers up to 10,000 years ago during the last Ice Age, Abu Dhabi's ground-water reserves recharge so slowly that they are in effect non-renewable, she warned.
"In areas of Abu Dhabi such as Al Ain, Al Shweib and Liwa, 50 years ago groundwater was easily accessible," she said.
"The groundwater was between half a metre and a metre below the surface and wells could be dug by hand," Ms Al Mubarak said.
Overuse of the water for agriculture, forestry and the oil sector has tapped a substantial amount of the reserves and at some places ground water depletion is so significant that the water table has dropped by as much as five metres a year.
In 2011, total demand for water in Abu Dhabi was 3,313 million cubic metres. Two thirds, 67 per cent, of this demand was filled by ground water reserves, 29 per cent from desalinated water and 4 per cent from recycled water.
From 2009 to 2011 the amount of water used in irrigation fell by 7 per cent, possibly as a result of growing fewer water-intensive crops such as Rhodes grass. However, more needs to be done and the agency has made extending the life of Abu Dhabi's groundwater reserves a strategic priority.
In addition to possible changes to the law, other approaches supported by the agency involve supporting agriculture in greenhouses and the use of hydroponic systems, which can be as much as 80 per cent more water efficient.
While agriculture and forestry account for the bulk of Abu Dhabi's ground water use, experts suspect that most of the emirate's potable water, produced at desalination plants, is being used outdoors in private gardens and swimming pools, and for non-essential tasks such as car washing.
The emirate's Regulation & Supervision Bureau said last week that of three billion litres of water produced in Abu Dhabi every day in 2011, only about 680 million litres were returned to the sewage treatment system, with the rest unaccounted for.
Like the rest of the UAE and the Arabian Gulf, Abu Dhabi produces its potable water in combined-cycle desalination and power plants. This has significant environmental costs. In 2010, almost 30 per cent of greenhouse gas emissions in Abu Dhabi were produced by the power and water sector.
Inefficient use of potable water also has serious financial implications. In 2011, it cost on average Dh10.43 to produce a cubic metre of water through desalination. Emiratis receive water free, and expatriates are charged Dh2.2 a cubic metre. The difference is covered by the Government.
The International Water Summit, which is part of Abu Dhabi Sustainability Week, concludes today.