Groundwater & Aquifers

Groundwater is the region’s largest water resource and its least visible. It is the most relied-upon source in at least 11 of the 22 Arab states, and more than 80% of freshwater withdrawals in Libya, Djibouti, Saudi Arabia and Palestine.⁴ Unlike a river, nobody can see it. Unlike a reservoir, nobody can easily measure what is left.

The satellite record puts hard numbers on the decline. NASA’s GRACE mission measured 143.6 km³ of fresh water lost across the Tigris and Euphrates basin and western Iran in the seven years from 2003 to 2009, nearly a Dead Sea’s worth. Roughly two-thirds of it, 91.3 ± 10.9 km³, came out of groundwater, at 17.3 ± 2.1 mm a year of equivalent water height against a total storage loss of 27.2 ± 0.6 mm a year.¹ It remains the clearest single measurement of a region spending its buffer.

Much of this water is not renewable on any human timeframe. The Nubian sandstone was filled in the Pleistocene, and its recharge today is described as effectively zero, so pumping it is closer to mining than to harvesting.²⁸ Saudi fossil water in the north is about 20,000 years old, and rainfall of 100 to 200 mm a year does not replace it.²⁷ For the Gulf states as a group, depletion of non-renewable groundwater has been estimated at 317% of the renewable volume.⁴

The renewable aquifers, the coastal and alluvial systems, are usually being drawn down faster than rainfall replaces them, which pulls seawater inland and pushes salinity up. The Arabian Aquifer System sits among the most overstressed on earth on the GRACE-based stress ratios, though the same study puts the Murzuk, North Western Sahara and Nubian systems above it, so the superlative belongs to the group rather than to one aquifer.²

For companies and lenders, this is a market defined by measurement and remediation. It covers drilling and well-field rehabilitation, monitoring and metering, managed recharge, brackish desalination, and the modelling work behind every abstraction licence and transboundary negotiation.

Four systems dominate the map. The Nubian Sandstone Aquifer System, among the largest bodies of fresh water on earth, underlies Egypt, Libya, Sudan and Chad and feeds Libya’s Great Man-Made River. The North Western Sahara Aquifer System, NWSAS in English and SASS in the French literature, is shared by Algeria, Tunisia and Libya. The Saq and Ram sandstone, known in Jordan as Disi, runs under Saudi Arabia and Jordan and supplies Amman through a 325 km conveyor. The Umm er Radhuma and Dammam limestones stretch beneath most of the Gulf peninsula, and the regional inventory maps them as three separate sections rather than one.⁸

The systems, and what is known about them

The region’s major aquifer systems, largest first. Where the regional inventory and IGRAC delineate the same system differently, both figures are shown.

Sources: UN-ESCWA and BGR, Inventory of Shared Water Resources in Western Asia (2013), groundwater chapters; Observatoire du Sahara et du Sahel (2008) for the North Western Sahara; the Joint Authority figures for the Nubian Sandstone; Mabrouk et al. (2018) for the Nile Delta volume; IGRAC, Transboundary Aquifers of the Middle East and of Africa (2022) for the delineated extents. The two extent columns disagree because they map different things, and a storage figure for a fossil system is a stock estimate, not water available for use.

The four systems, and the state of each

Nubian Sandstone: the largest, and the one being spent

About 540,000 km³ of water is thought to be stored, of which some 15,340 km³ is considered exploitable, across an area the Joint Authority puts at 2 million km² and IGRAC delineates at 2.45 million.¹⁴¹² Recharge today is effectively zero.²⁸

Libya’s network is about 4,500 km long and supplies more than 70% of its urban areas. In December 2024 the authority committed to a fifth and final phase costing US$7 billion, against roughly US$25 billion spent since the project’s inception in the early 1980s.²⁹ Nothing about the resource is renewable on a human timeframe.

Saq and Ram, known in Jordan as Disi

Sandstone running under Saudi Arabia and Jordan, supplying Amman through a 325 km conveyance since 2013 at 100 million cubic metres a year from a field of 55 wells, under a 25-year build-operate-transfer concession.¹⁹¹⁵

The asymmetry is the point. Jordan holds 4 to 10 billion cubic metres of the system against Saudi Arabia’s 740 billion, recharge is 2 to 20 mm a year, and Saudi abstraction near Tabuk rose from about 29 million cubic metres a year in 1983 to between 1,050 and 1,700 million by 2004, against recharge of 3 to 10 million.⁶ It is also a bridge rather than a supply, which is why Jordan spent the years it bought building a carrier from the sea.

Umm er Radhuma and Dammam: the Gulf’s shallow reserve, turning brackish

Three mapped sections, not one. The southern section under Oman, Saudi Arabia, the UAE and Yemen covers about 680,000 km²; the central section under Bahrain, Qatar and Saudi Arabia about 281,000; the northern section under Iraq, Kuwait and Saudi Arabia about 246,000, where water levels have fallen by up to 60 metres in both formations.⁷⁸⁹

Abstraction of 97 million cubic metres a year in Bahrain, 91 in Qatar and 608 in Saudi Arabia has left the central section open to salinisation, and seawater intrusion has been reported up to 8 km inland on the Omani coast.⁵¹ Where the system still works for cities, it works because water was put back: Abu Dhabi banks desalinated water in the Liwa dunes as a strategic reserve, which is storage rather than abstraction.

North Western Sahara: shared by Algeria, Tunisia and Libya

Over 1 million km², of which 700,000 in Algeria, 80,000 in Tunisia and 250,000 in Libya, recharged by only about 1 billion cubic metres a year.¹⁰ IGRAC lists the system with two riparians rather than three.¹²

Abstraction has quadrupled, from 0.6 billion cubic metres a year in 1970 to 2.5 billion today, which is two and a half times recharge, drawn from roughly 8,800 water points.¹⁰ Its pressure comes from irrigation rather than cities, which makes it a problem of metering wells rather than of building plants.

The renewable aquifers, which are the ones actually failing

Coastal and alluvial systems do recharge, and are almost everywhere drawn down faster than rainfall replaces them. That pulls seawater inland and pushes salinity up.

Morocco’s Souss is the clearest measured case: piezometer 859/62 in the upstream Souss fell 1.9 metres a year between 1998 and 2008 and 3.5 metres a year between 2012 and 2020, while the correlation between the rainfall index and the standardised water-level index across the Souss and Massa is 0.07, which points at pumping rather than drought.³⁵ In Iraq’s Sinjar and Ba’aj districts, where groundwater is the only source, more than 75,000 people in Wardiya, Solagh, Tal Banat and Tal Qasab face shortages, rainfall has fallen 40% in five years and 15% of residents have already migrated.³⁰

One scheme in this sector, examined in full: what was built, what it cost, what worked and what did not.

The hub's headline metric for all twenty countries. Hover, tap or focus a country; the ranked table sits alongside.

Four independent measurement methods now cover the region: satellite gravity for whole aquifers, piezometric records for national totals, radar interferometry for the ground surface, and well logs for individual basins. They agree on direction and differ on magnitude, which is worth saying plainly rather than averaging away.

North Africa, from satellite gravity

Between 2003 and 2016 the Nubian system lost around 50 km³ and the North Western Sahara more than 30 km³. The Nubian loss is attributable to abstraction alone; the North Western Sahara loss is part climate and part abstraction, and the nearby Tindouf basin, which tracks rainfall closely, lost under 10 km³.²¹ Depletion rates have been put at 6.08 ± 1.9 km³ a year for the Nubian and 2.69 ± 0.8 for the Sahara, against non-satellite estimates of 2.2 and 2.17 km³.³

Iran, from well records and radar

Piezometric records across 478 sub-basins give a loss of about 74 km³ between 2002 and 2015, some 5.25 km³ a year, with extreme overdraft across roughly 77% of the land area and a national deficit of 1,737 million cubic metres a year.²²²³ These are well records, not gravity measurements, so they cannot be added to GRACE totals.

The ground is following the water down. Sentinel-1 interferometry for 2014 to 2020 makes Rafsanjan the fastest-sinking place in the country at 37 cm a year, ahead of Arzuiyeh at 34, Savojbolagh at 29 and Nazarabad at 27, with subsidence hazard across 56,000 km², 3.5% of Iran, where more than 14 million people live.²³ Mashhad has the longest record and the clearest pairing of cause and effect: a water table down 65 metres over four decades, and vertical deformation of about 19 cm a year.²⁴

Egypt and Saudi Arabia

For Egypt, GRACE gives depletion of 0.64 ± 0.03 cm a year over Sinai and 0.32 ± 0.03 over the Nile Delta aquifer between 2003 and 2021, with about 7.25 km³ taken from the Nubian in the Western Desert. Losses from the Moghra aquifer rose roughly eightfold across the same period, from 32 to 262 million cubic metres a year.²⁵

Saudi Arabia’s total water storage fell 7.94 ± 0.22 mm a year from 2002 to 2016. The Saq is where the methods genuinely conflict: the same study reports a significant negative storage trend over the aquifer and a positive recharge estimate of 4.65 ± 0.10 km³ a year, so no single clean figure for the Saq can responsibly be quoted.²⁶ Storage under the northern desert is put at 252 to 870 km³, and hydrologists expect only about 50 more years of economic pumping, which is why the wheat programme was phased out from 2008 and ended in 2016.²⁷

Jordan, Morocco and Yemen, from the basin records

Six of Jordan’s twelve basins are pumped at 146 to 235% of safe yield; Azraq, whose four springs dried out in 1992, has fallen about 25 metres in 28 years against a safe yield revised from 20 to 24 million cubic metres a year.⁴² A separate ministry-based account puts national abstraction at 625 million cubic metres from 3,138 known wells, 130% of a 275 million safe yield, with water levels across six basins falling about a metre a year and the worst single well at nine.⁴¹

Morocco’s aquifers run at 100% of recharge in the Moulouya to 248% in Chtouka-Massa, with Tadla, Souss, Haouz and Saïss between 150 and 170%; national withdrawals of about 5 billion cubic metres exceed renewable groundwater by 28%.³³³⁴ Levels have dropped 20 to 65 metres across all basins in 30 years.³³

In Yemen the water table under Sanaa falls about six metres a year, against two and a half to four and a half elsewhere, and western Yemen is at its lowest level since satellite records began in 2002.³¹³² Well counts disagree: roughly 100,000 mostly illegal wells are reported for Sanaa and its surroundings alone, and roughly 100,000 for the whole country.³²³¹

One caveat applies to the dashboard above. The World Resources Institute did not update its groundwater-table-decline indicator for the Aqueduct 4.0 release, so that layer is not 4.0-era data and should be read as a floor.⁷² And any claim that an aquifer becomes uneconomic within a generation rests on a storage estimate, not a depletion rate: for the Sahara, time to 90% depletion ranges from about 10 years to 150,000 years depending on which storage estimate is used.³

Quantity and quality fail together. As a water table drops, the remaining water sits in older, more mineralised rock and gets saltier. Coastal aquifers draw seawater inland to replace what was pumped. Shallow contamination, meaning nitrate from fertiliser, sewage from unsewered districts and industrial discharge, concentrates in a smaller volume.

Gaza is the extreme case, and the best documented. Some 97% of the water extracted from its coastal aquifer is unfit for human consumption against WHO standards, because the only aquifer has been depleted by over-extraction and contaminated by sewage and seawater.⁴⁵⁴⁶ A survey of 115 municipal wells found chloride averaging 1,419 mg/L and peaking at 9,491, nitrate averaging 112 mg/L against a WHO guideline of 50, and fluoride up to 2.6 mg/L.⁴⁷ In the 2017 monitoring round only about one well in nine met the nitrate limit and one in five the chloride limit, and salinity has risen by a third in twenty years while nitrate shows no clear trend.⁴⁸

On the Gulf coast the same process is measured in kilometres. At Al-Qatif in eastern Saudi Arabia the shallow aquifer runs from 4,220 to 34,090 mg/L of dissolved solids, averaging 10,108, with the intrusion front about 3.5 km inland.⁴⁹ In the multi-layered aquifers further along the coast, dissolved solids range from 1,955 to 15,560 mg/L.⁵⁰ On the Libyan coast intrusion was already estimated to be advancing 100 to 250 metres a year in FAO’s 1997 regional survey.⁵⁴

In the northeastern Nile Delta the salt has reached the soil. Electrical conductivity across surveyed fields runs from 0.53 to 49.7 dS/m and averages 22.2, with 42.8% of the area strongly saline and 21.4% very strongly saline, over shallow groundwater of 837 to 34,900 mg/L sitting half a metre to three metres below the surface.⁵² Modelling the seawater wedge is harder than it looks: published reconstructions differ on the position of its toe by up to 10 km.⁵³

Nitrate and fluoride are local rather than regional problems, and should not be generalised. On the Angads plain near Oujda in Morocco, nitrate runs from 7 to 171 mg/L and nearly half of samples exceed the WHO limit.⁵⁶ Globally about a tenth of fluoride measurements exceed 1.5 mg/L, and across 15% of Africa’s land area the probability of exceeding it is above one in two; in Iran’s Bushehr province every monitored station averaged above the guideline, from 1.52 to 3.64 mg/L.⁵⁷⁵⁸

Sources for the case files: Parimalarenganayaki (2020) on the Salalah recharge scheme⁵⁹; Shomar and Rovira (2023) on Gaza’s municipal wells⁴⁷; FAO, Irrigation in the Near East region in figures (1997), for the Iraqi salinity shares⁵⁵; the 2024 Scientific Reports survey for the Nile Delta.⁵²

The engineering response is managed aquifer recharge: deliberately putting water underground when it is available and taking it out when it is not. In a region where surface reservoirs lose a punishing share to evaporation, an aquifer is the cheapest large-scale storage available.

Abu Dhabi’s Liwa reserve, and what is actually proven

The scheme holds more than 26 million cubic metres of desalinated water in a dune aquifer, enough to supply the emirate for about 90 days, filled from the Shuweihat plant at 32,000 cubic metres a day over 27 months, with some 315 recovery wells reaching 80 metres and a recovery capacity of 100 million gallons a day, completed in January 2018 at about US$435 million.⁶¹⁶⁰ Earlier figures in circulation are 17 million cubic metres injected in 2012 and a 23 million target, which is worth knowing before quoting any single volume.⁴³⁶²

A recovery efficiency of 88% is widely quoted.⁵⁹ What is documented is the pilot, where recovery through the wells around the infiltration basin worked without problems and the recovered water most likely met Abu Dhabi’s drinking water standards.⁶⁰ No published account covers a full-scale recovery cycle, so treat 88% as a claim rather than a demonstrated result.

Recharge dams, which are the region’s largest MAR programme by count

Oman operates 209 dams with a combined capacity of about 458.7 million cubic metres, having impounded more than 3.17 billion cubic metres of floodwater to the end of 2025; the ministry’s own figure in December 2024 was 191 dams and 357.7 million cubic metres, so the series is moving.⁶⁵⁶⁶⁶⁴ By type, the stock is 89 surface retention dams, 45 purpose-built recharge dams and 14 flood protection dams, all built since 1985, with recharge efficiency measured at up to 75% in Dhofar.⁴⁴

Saudi Arabia has 522 dams with 2.3 billion cubic metres of capacity, of which 1.6 billion is utilised, for runoff collection, storage and recharge.⁶⁷ The UAE’s AQUASTAT register lists 68 dams built between 1982 and 2004, including Al Tawiyeen at 18.5 million cubic metres; at the Wurayah and Tawyeen dams, 20 to 40% of stored water was measured as reaching the aquifer.⁶⁸⁵⁹

Reuse to recharge, where it exists

Bahrain has recharged the Khobar aquifer with treated effluent since 1986.³⁹ Oman injects treated wastewater in a managed way in exactly one place, Salalah, where it pulled the saline front back from 3.4 to 2.7 km.⁴⁴⁵⁹ Tunisia recharged 20 of 28 targeted aquifers with 38.4 million cubic metres in 2011, 92% of it from hill dams and only 4% from treated wastewater, under a policy that ran experimentally from the 1970s and structurally from 1992.⁴⁰

Gulf aquifer storage and recovery schemes with published numbers include Kabd in Kuwait, recovering 100,000 cubic metres a day from eight wells at 77% efficiency, Sharjah, and Nizwa in Oman.⁵⁹ Qatar is often listed alongside them, but the peer-reviewed work there is a siting study rather than infrastructure, identifying zones that could hold up to 182.8 million cubic metres if a scheme were built.⁶³

An aquifer is the only reservoir in this region that does not evaporate.

Tracked projects involving wells, well-fields, groundwater supply and recharge. Hover a marker for the project and its status; click through to the database.

Only a handful of tracked projects are primarily groundwater schemes. That is the market, not a gap in the database: the region's capital pipeline is dominated by desalination and reuse, and groundwater is mostly abstracted through dispersed private wells that no tender register captures.

The tracked projects in this sector and the structured procurements coming next, straight from our databases.

Projects

Every country in the region licenses wells. Almost none measures what comes out of them, and fewer still charge for it. The gap between the statute book and the wellhead is where groundwater policy actually fails.

• Iran: of about 416,000 authorised agricultural wells, roughly 125,000 carry volumetric smart meters, under a quarter, and more than 400 plains are classed critical or prohibited
• Jordan: By-law 85 of 2002 licenses drilling, rigs and abstraction, but the first 150,000 cubic metres from a single well remain free of charge
• Morocco: Article 115 of Law 36-15 created aquifer contracts, and by the state auditor's 2018 review only one had been signed against a target of ten
• Oman: 180,444 wells and 4,198 aflaj are registered, and meters have effectively never been installed beyond pilots
• Abu Dhabi: Law 6 of 2006 licenses drilling and over 80,000 wells are permitted, but farm metering was dropped after landowner resistance
• Tunisia: authorisation is required only below 50 metres, and the 9,300 deep boreholes counted in 2010 had no meters, so declared volumes cannot be checked

Iran shows the measurement gap at its largest. Of about 416,000 authorised agricultural wells, roughly 125,000 carry volumetric smart meters, under a quarter, and the obligation to fit them runs back through the Fair Water Distribution Law and at least fifteen later annual laws without a completion deadline.⁶⁹

Jordan has gone furthest on enforcement. More than 1,293 illegal wells had been backfilled or capped by 2016, 644 of them by June 2015, alongside 1,228 notices, halted rigs and stopped excavators, with meter-installation compliance reaching 95%; up to 159 drilling rigs had been confiscated by April 2015.⁴¹³⁸ The pricing, though, still exempts the first block, which is the clearest example in the region of measuring without charging.⁴¹

Morocco shows the other failure mode, which is an instrument that exists on paper. The aquifer contracts rest on Article 115 of the 2016 water law, piloted on Souss and Mnasra from 2007 and codified after an interministerial circular in November 2013; by the Cour des comptes’ review only the Souss contract had been signed against ten targeted by the end of 2018, the implementing decree was unpublished, Chtouka was the only gazetted safeguard zone, and more than 102,264 abstractors were operating outside the authorisation regime altogether.³⁶³⁷ Metering, a key Souss measure, was postponed.³⁸

The older statutes are sound enough. Oman declared its groundwater public wealth by royal decree in 1988 and required registration and permits from 1990, with power to set permissible discharge and require flow meters; the well inventory that followed registered more than 167,000 wells, and the law on meters was never effectively applied.⁴⁴⁶⁵ Egypt has required a ministry permit to dig any well since Article 46 of Law 12 of 1984, for no more than ten years at a time.³⁹ Saudi Arabia regulated drilling permits by executive order in 1989 for farms above 2.5 hectares.³⁹ In Algeria’s Wilaya of Blida, on the Mitidja plain, 2,000 illegal wells sit alongside 1,200 legal ones.³⁹ Abu Dhabi prosecuted 34 illegal-drilling cases in 2012 and 87 in 2013, and issues about 1,750 new well permits a year.⁴³

Almost every major aquifer here crosses a border, and almost none is governed by a binding sharing agreement. IGRAC’s current global map, published in 2021, identifies 468 transboundary aquifers and aquifer systems, up from 366 in 2015, of which 106 are in Africa.¹¹¹² For the Arab region specifically, 42 transboundary aquifer systems cover almost 58%% of the land area, and every Arab state except the Comoros draws on at least one.⁴ Across Africa, cooperation has been formalised for seven.¹³

The regional inventory is blunt about the record. Its 26 chapters, nine on surface water and 17 on groundwater, conclude that there are no specific agreements on shared groundwater resources in Western Asia, though a few bilateral agreements include groundwater provisions.⁵ That was written in 2013, which is what makes the next paragraph the exception.

Disi, 2015: the one operational aquifer agreement

Signed in Riyadh on 30 April 2015 and in force from the date of signature. It creates a protected area of about 400 km² on each side of the border, requires the elimination within five years of all activities there that depend on extracting groundwater, adds a management area of roughly 1,000 km² each side limited to municipal abstraction, and is reviewed every 25 years.¹⁸¹⁵ The agreement works with survey markers rather than a fixed width, so the “10 km each side” figure in press coverage should not be repeated.

Nubian Sandstone: an authority, and data sharing

Egypt and Libya created a joint authority in 1989 and adopted its constitutive agreement in 1992, seated in Tripoli; Sudan joined in 1996 and Chad in 1999.¹⁴¹⁶ Two further instruments on monitoring and the exchange of groundwater information followed in October 2000, and all four water ministers signed a Regional Strategic Action Programme on 18 September 2013.¹⁶¹⁴ None of it allocates water.

North Western Sahara: a mechanism without a treaty

There is no treaty. A procès-verbal was endorsed separately by Algeria on 6 January 2003, Tunisia on 15 February and Libya on 23 February.¹⁷ Options agreed at FAO headquarters in December 2002 led through Algiers and Tunis in 2005 to the creation of a consultation mechanism and its secretariat at the Sahara and Sahel Observatory in November 2007.¹⁰

The Mountain Aquifer: interim arrangements, thirty years on

Governed by Article 40 of Annex III to the Oslo II agreement of 28 September 1995, under which Israel recognised Palestinian water rights in the West Bank to be negotiated in permanent status talks, a Joint Water Committee was created for the interim period, future Palestinian needs were estimated at 70 to 80 million cubic metres a year, and 28.6 million a year was to be made available.²⁰ The interim period has outlasted the arrangement.

Our Region Atlas maps the transboundary aquifer systems (IGRAC) alongside river basins and infrastructure.

Where the commercial and donor activity concentrates:

The bodies that commission, regulate or deliver in this sector, and the names that recur across its tenders.

• Ministry of Environment, Water & Agriculture (MEWA)Ministry · Saudi Arabia
• Ministry of Water & Irrigation (MWI)Ministry · Jordan
• Environment Agency – Abu Dhabi (EAD)Environment · United Arab Emirates
• Hydraulic Basin Agencies (ABH, ×10)Basin & resources authority · Morocco
• UN-ESCWARegional body · Regional

Mandates, procurement routes and the rest of the region’s institutions are in the decision-maker directory.

The direction of travel is not in doubt. What is genuinely uncertain is the timetable, and the uncertainty sits in storage rather than in depletion: for the Sahara systems, the time to 90% depletion ranges from about a decade to 150,000 years depending on which storage estimate is used.³ Saudi hydrologists expect about 50 more years of economic pumping in the north.²⁷ Some coastal systems, meanwhile, are already effectively lost to salt.

The encouraging signal is that the biggest users have started acting. Saudi Arabia ended its wheat programme to save groundwater, Abu Dhabi banks desalinated water underground, and Jordan protects the Disi zone by treaty. The discouraging signal is that solar pumping has removed the fuel-cost brake on abstraction, exactly where governance is weakest, and has the potential to exceed what diesel ever pumped.³²

Strategic storage has also acquired a security argument. Desalination supplies about 90% of Kuwait’s drinking water, 86% of Oman’s, 70% of Saudi Arabia’s and 42% of the UAE’s, and in early March 2026 reported strikes damaged desalination plants in both Bahrain and Iran.⁷⁰⁷¹ The damage was limited and supply held, but the exposure was the point, and an aquifer is the one reserve that cannot be hit from the air. Groundwater management here is now less a hydrological problem than an institutional one.

Standing references for this sector. Every one is a real work and every link was checked.

• IGRAC, Global Groundwater Information System. The transboundary aquifer inventory, and the polygons behind the aquifer maps on this site. un-igrac.org
• Transboundary Waters Atlas, the shared-basin and shared-aquifer reference this site links to for every cross-border system. transboundarywatersatlas.org
• FAO AQUASTAT, the standing database of national water resources, withdrawals and irrigated area. The denominator behind most figures on this site. fao.org