UAE groundwater levels falling

on .

Abu Dhabi: The UAE’s groundwater is being pumped out for irrigation at a rate of about 860 billion litres per year, and is dropping at a rate of 0.5 centimetres a year, according to new research from the Masdar Institute of Science and Technology in Abu Dhabi.

This is significant, considering that the UAE relies on its groundwater reserves to provide over 50 per cent of the country’s freshwater.

The research findings provide the government with crucial information needed for optimal management of the country’s freshwater reserves.

While groundwater provides over half of the country’s freshwater needs, most of it goes toward the agricultural sector for irrigation. Desalination provides around 37 per cent of the UAE’s water demand, which is used mostly for industrial and domestic consumption. The remaining portion, around 12 per cent, is recycled water, which is used for landscaping irrigation. Considering the dependence on groundwater, knowing its status is crucial in water management.

Masdar Institute graduate student Maria del Rocio Gonzalez Sanchez created the UAE’s first ‘water budget’ — a term that reflects the relationship between all inputs and outputs of water through an area.

Stopping unsustainable and uneconomical irrigation practices in the agricultural sector is the immediate solution to the water scarcity in the UAE, Sanchez toldGulf News on Wednesday.

One-third of recycled water is discarded for want of infrastructure in the country and using that water for irrigation is also a solution, said the 33-year-old researcher from Spain. Improving the irrigation system is essential to make the agriculture sector sustainable and cost-effective, she said.

Dr Taha B.M.J. Ouarda, Professor of Water and Environmental Engineering and Head of the Institute’s Centre for Water and Environment (iWater) and faculty supervisor to Sanchez, said: “Water budget is just like managing your finances — you need to know how much money you have in savings, how much your income is, and what your expenses are, so you can manage it all efficiently.”

In a water budget, the ‘income’ is the amount of usable water that flows into the country through precipitation, or is produced through desalination and wastewater treatment. The ‘savings’ are the amount of groundwater being stored in underground aquifers; and the ‘expenses’ include the amount of water that leaves the groundwater through evapotranspiration and human activities.

The research measured ‘expenses’ of evapotranspiration — which refers to soil evaporation and plant transpiration — and groundwater depletion. Sanchez found that despite the UAE’s slight rise in rainfall over the past 15 years, evapotranspiration has been taking water out of the ground at approximately the same rate that rainfall has been adding to it. This means that there is no real net gain to the UAE’s groundwater reserves from rain presently.

Sanchez used remote sensing and satellite-based measurements to determine variables that would be difficult to obtain by other methods. For instance, she used data from Nasa’s Gravity Recovery and Climate Experiment (GRACE) to determine UAE groundwater levels and the rate at which water is lost through evapotranspiration.

According to the Environment Agency-Abu Dhabi (EAD), the emirate’s aquifers — including those with 10,000-year-old water reserves — are expected to run out in 50 years, if the current rate of water extraction continues. It is estimated that Abu Dhabi alone uses more than 3 billion cubic metres of water per year — more than enough to fill 1.2 million Olympic-sized swimming pools.

At the current rate of consumption, the country is utilising underground water resources more than 20 times as fast as they can be recharged. And this situation is only likely to be exacerbated with projections indicating that Abu Dhabi’s population and economy are likely to triple in the next 15 years.

Figures

860 billion litres per year groundwater use for irrigation

0.5cm a year depletion rate of groundwater

37% of UAE’s water demand met by desalination

12% of UAE’s water demand met by recycled water

50% of UAE’s water demand met by groundwater

http://gulfnews.com/news/uae/environment/uae-groundwater-levels-falling-1.1501491