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Water Quality in UAE

جودة المياه في الإمارات العربية المتحدةUAE- Liwa Desert water quality in UAE

Photo 1: Salt pan in Liwa Desert, UAE (Source: Obaid Obaid, Flickr).

Groundwater quality in the shallow and deep aquifer systems, particularly in the Bajada region, ranges from 600 to 2000 parts per million (ppm). Household water quality is considered one of the best in the world, reaching 96%.[1]

Groundwater accounts for 44% of the total used water resources. There was a significant drop in groundwater levels of about 10 metres per decade until the mid-1990s, and 70 metres since then.[2] The UAE is currently using groundwater reserves more than 20 times faster than they can be recharged.[3]

The agriculture sector is the largest water consumer, accounting for 34% of the total water usage. It is also one of the main contributors to water quality deterioration, due to excessive water abstraction for farming and as a result increased salinity and chemicals. According to the Food and Agriculture Organization of the United Nations (FAO), ‘The groundwater level has declined from 60 metres to 80 metres in Hamaranyah and Jabal al-Heben in the Northern Emirates due to intensive agriculture activities.’[4] Furthermore, recent data from the Environment Agency Abu Dhabi revealed that there was a decline in the water level of Khazna, west of al-Ain, from 56 metres in 1999 to 96 metres in 2014,[5] as well as a decline in the water level of Sweihan from 46 metres in 1998 to 104 metres in 2013.[6]

The return flow from irrigation to the groundwater reservoir is estimated at an average of 25% of the gross water application. Although this irrigation return flow increases the recharge to groundwater, it diminishes the water quality. This is because the percolating poor-quality water dissolves salts from the soil and underlying strata and carries them to the aquifers bearing relatively fresh water. Map 1 shows the groundwater salinity across the UAE.

Groundwater was and still is one of the main water sources in the UAE, but due to rapid expansion mainly in agricultural areas, two major environmental problems have occurred: 1) overabstraction of groundwater for agriculture, which has caused a sharp drop in water levels in freshwater aquifers; and 2) salt water intrusion from the sea in coastal areas (near sabkha (marshes)) into shallow freshwater aquifers.

United Arab Emirates

Map 1. Groundwater salinity across the UAE.[7]

Environmental pollution

Pollution from sewage

While the coverage rate of basic sanitation services appears to be quite high, a fairly large portion of the country is covered by on-site sanitation facilities such as septic tanks and cesspits that may not provide adequate water pollution control measures in high-population areas. Municipal wastewater from urban centres is discharged either into the sea for coastal cities or into the alluvial channels for inland cities and towns. In rural areas, improperly constructed and poorly maintained septic tanks and cesspools have led to percolation of effluent to shallow aquifers and to contamination of the water supply. As a result, the shallow aquifers are polluted from concentrated use of septic systems in some areas, giving rise to high levels of nitrates in the shallow groundwater reserves.

Furthermore, soil salinization resulting from deterioration in the quality of the groundwater used in irrigation has led to a general reduction of the cultivated lands. Water logging and salinization problems are increasing at a high rate, underlining the urgent need to study drainage requirements, both for agricultural and landscaping areas, and to convince farmers/users of the need for adequate drainage facilities.

Groundwater pollution

Groundwater pollution is caused by several factors. The most important is overpumping from wells.  Other factors include seawater intrusion, irrigation returns, heavy application of chemicals, high evaporation rates and liquid effluents from septic tanks.

Extraction of groundwater beyond safe yield levels has also resulted in the pollution of the existing groundwater aquifers. This is due to seawater intrusion and upcoming brackish and saline water from lower aquifers. Many wells have been abandoned as a result of seawater intrusion.

Environmental impacts of desalination plants

Desalination plants consume high amounts of energy. Their capital costs and space requirements are also relatively high. There are many potential negative environmental impacts from desalination plants, such as the adverse effect on land use as most of the factories are located near the shoreline, which serve as the sites for industrial plants and for pumping stations rather than for recreation and tourism. Another consideration is the noise impact of desalination plants especially if located near populated or tourist areas. If a desalination plant is constructed inland, then any leakage from the pipes may result in penetration of salt water to the aquifer. In addition, there are negative impacts on the marine environment because of the reject brine

Any chemicals added to the desalination process to reduce scale (deposition of particles on a membrane, causing it to plug) and corrosion might be discharged to those water bodies, negatively affecting marine biodiversity. Likewise, inland brackish water desalination plants can also face major challenges in disposing of brine discharges in a safe manner and incur heavy treatment costs.[8]

[1] UAEZOOM, 2016. ‘96% is the ratio of tap water quality in Abu Dhabi.’ Available at www.uaezoom.com/articles/جودة-مياه-الصنبور-في-أبوظبي/, accessed 11 March. 2017.
[2] Ministry of Environment and Water, 2015. UAE State of Environment Report.
[3] Gulf Business, 1 May 2016. ‘UAE eyes man-made mountain to maximise rainfall.’ Available at http://gulfbusiness.com/uae-eyes-man-made-mountain-to-maximise-rainfall/, accessed 19 January 2017.
[4] The National, 21 February 2015. ‘Groundwater at danger level in UAE.’ Available at www.thenational.ae/uae/groundwater-at-danger-level-in-uae, accessed 21 January 2017.
[5] Ibid.
[6] Ibid.
[7] Ministry of Environment and Water, 2015. UAE State of Environment Report.
[8] Abdel Raouf, M., 2009. ‘Water Issues in the Gulf: Time for Action.’ Middle East Institute, Washington, DC.