Bahrain's geography: an archipelago that keeps adding land

Why no two sources agree on Bahrain's area

Most countries have an area that changes only when a border moves or a survey improves. Bahrain's changes because land is added to it, and every source prints the figure for the year its authors measured. Wikipedia's geography article gives about 694 square kilometres in one paragraph and 780 in its data box; its main article gives 665 before reclamation and 780 after; Minority Rights Group gives some 668. None is wrong for its date, and none carries that date.

The Land reclamation in Bahrain article on Wikipedia supplies two dated points: 665 square kilometres in 1981 and 741 in 2007, an increase of 11%. The satellite study published by the American Association for the Advancement of Science (AAAS) measured the main island and the islands next to it from Landsat imagery and found the land grew from approximately 650 to 730 square kilometres between 1987 and 2013.

The archipelago's shape is less disputed. Britannica describes two groups of islands. Bahrain Island and its neighbours extend about 50 kilometres from north to south and 16 from east to west; the Hawar Islands lie about 19 kilometres to the south-east, close to the coast of Qatar. Wikipedia puts Bahrain Island at 604 square kilometres, about 78% of the land, and 48 kilometres long. The islands lie about 24 kilometres off the Saudi coast and 28 kilometres from Qatar.

How the sea became building land

The Gulf off the north and east coasts is shallow enough that land can be dredged up from the seabed cheaply, which is how the United States Geological Survey explains the pace of the work: the coastal zone grew by about 40 square kilometres in less than two decades. The AAAS study found that the first phase, about 10 square kilometres between 1987 and 1998, went mainly onto Muharraq Island in the north-east, and that by 2013 approximately another 50 square kilometres had been added. In August 2008, Wikipedia records, the islands and island groups numbered 84; the main Bahrain article counts 33 natural islands and 50 artificial ones.

The new land was built on as fast as it was made. The AAAS classification found built-up land more than doubling over the 26 years of its study, from approximately 76 to 155 square kilometres, and the USGS summary reports the same doubling of the urban extent. The study was commissioned by the Bahrain Center for Human Rights, which had raised concerns about what the changes meant for access to the coast and to water.

The sea paid for it. Wikipedia's account of the reclamation, drawing on marine studies, records that an estimated 95% of the native mangrove forests have been lost, that Tubli Bay shrank by 40%, and that a further 150 square kilometres of Bahrain's maritime area is believed to have been destroyed by dredging and fill.

What the islands are made of

Beneath the new land the old island is a single geological dome. Britannica describes gently folded sedimentary rock, limestones, sandstones and marls laid down from about 145 to 2.6 million years ago. The surface rises from flat raised beaches around the coast to a ring of inward-facing cliffs around an oval central depression, and in the middle of that depression stands Jabal al-Dukhan, the Mountain of Smoke, named for the mists that often cover it. Britannica and Wikipedia give its height as 134 metres; the CIA World Factbook, quoted in Wikipedia's data box, gives 122.

The dome is also the oil field. Most of the country's wells are near Jabal al-Dukhan, and the first well of 1932 sits below it.

Wikipedia's geography article, quoting an older geological survey, gives the proportions: the cliffs stand eighty to one hundred feet high, and the depression inside them is about twelve miles long and four wide. The limestone that forms most of the island is porous, and it holds most of the water in the northern half.

The south and west of the main island are a sandy plain with salt marshes. The north and north-west coasts are different: a fertile strip about five kilometres wide carries date palms and vegetable gardens, and Britannica credits that water-fed land with the island's historical importance as a harbour and trading centre. About 92% of the country is desert, and Britannica puts the arable share at less than 3%. The Hawar group is small and rocky; Hawar itself is 19 kilometres long and about one and a half wide. Britannica describes the group as inhabited by only a few fishermen and quarry workers and believed to hold oil and gas. Of the smaller islands near the main one, Nabih Saleh has freshwater springs that irrigate its date palms, and the rocky islet of Jiddah, once the state prison, has become a private residence.

Where Bahrain's fresh water comes from

No permanent river or stream exists on any of the islands. The water that made Bahrain worth settling comes from underground: rain falling on the western mountains of Saudi Arabia, in Britannica's account, flows east through porous rock and rises as artesian springs along the north coast, on the small islands and even in the sea off the north shore. The principal aquifer, the Dammam, is recharged by underflow from eastern Saudi Arabia.

That mix of fresh and salt water is one reading of the country's name. Bahrain means the two seas in Arabic, and Wikipedia records that the phrase is now taken to mean the bays east and west of the island, the seas to its north and south, or the fresh water under the ground and the salt water above it.

Growth outran it. The AAAS study cites annual water use rising from 138 million cubic metres in 1980 to 269 million in 2000, and the Dammam aquifer has turned saline where brackish water, seawater and water from the salt flats have seeped in. Since the early 1980s desalination plants have supplied the difference: about 60% of daily consumption in Wikipedia's figure, some three-fifths of all water used in Britannica's, powered by natural gas. The date palms went with the springs, and reports cited by the AAAS study describe the main island and its neighbours losing a substantial part of their palm groves.

How the heat and humidity shape the year

The climate has two seasons. From April to October afternoon temperatures average 40°C and can reach 46°C in May, June and July. The sea around the islands is so shallow that it heats quickly, which is why a Bahraini summer is humid as well as hot, especially at night. A hot, dry south-westerly called the qaws blows sand across the south of the island towards Manama, and the north-westerly shamal brings dust from Iraq and Saudi Arabia in June and July and damp air in winter. Winters, from November to March, run between 10 and 20°C, and humidity then often rises above 90%.

Rain is scarce and falls in winter, in short heavy storms that flood the dry wadis. Wikipedia gives an annual average of about 72 millimetres in one article and 70.8 in another, and Britannica says rain falls on about ten days a year. The World Bank's Climate Change Knowledge Portal, using the ERA5 reanalysis, gives a mean annual temperature of 26.24°C and precipitation of 63.68 millimetres for 1995 to 2014, and a warming rate of 0.25°C per decade since 1970. It projects a median rise of 1.76°C by 2040 to 2059 under the high-emission scenario SSP3-7.0.

The Zagros Mountains in Iran, across the Gulf, turn the low-level winds towards the islands, which is part of why the dust arrives when it does. Wikipedia's geography article describes more frequent extreme heat, drought, flooding and dust storms under a changing climate, and a threat from sea level rise to islands that rise only a few feet above the water at their edges. The government has committed to net zero emissions by 2060 and to a 30% reduction by 2035; emissions were about 42 tonnes per person in 2023, mostly from burning fossil fuels for energy.

Extremes run in both directions. On 20 January 1964 the temperature fell to minus 5°C at Awali, with icicles on trees and fences, and in April 2024 heavy rain across the Gulf flooded the country.

Where Bahrain's people live on the islands

Most of the population lives in the north of the main island and on Muharraq, the side with the springs. The 2020 census, published by the Information and eGovernment Authority and tabulated by the Gulf Labour Markets and Migration programme, counted 1,501,635 people in four governorates. The Capital Governorate, around Manama, held the most, and it was also the one with the largest share of non-Bahrainis.

The growth was recent. The USGS and AAAS both give a population of 213,000 in 1970; the AAAS puts it at 1,252,000 in 2010, and the USGS estimated over 1.5 million in 2023. Wikipedia gives 1,588,670 for 2024, of whom 739,736 were Bahraini nationals. Muharraq and Sitra are joined to the main island by causeways, and Britannica notes that those links carried residential and industrial building onto both islands.

What lives on the islands and the reefs

On land, desert conditions keep the wildlife sparse. Gazelles, hares, lizards and jerboas live in the dry interior, and Britannica suggests that the mongoose found in the irrigated gardens was probably brought from India. Forest covered about 700 hectares in 2020, up from 220 in 1990. Wikipedia counts 18 species of mammal, 25 of amphibians and reptiles and 307 of flora, and Britannica about 200 species of desert plant. The Arabian oryx, the national animal, was hunted out on the island and survives in the Al Areen Wildlife Park, the only protected area on land.

The sea is richer. Coral reefs cover much of the rocky seabed off the north, sea grass beds feed dugongs and green turtles, and in 2003 Bahrain banned the capture of dugongs, marine turtles and dolphins in its waters. Most birds are passage migrants: Britannica notes that birdlife is sparse except in spring and autumn, when birds rest on the islands between breeding and wintering grounds. More than 330 bird species have been recorded, 26 of them breeding, and up to 100,000 pairs of Socotra cormorants have been counted on the Hawar Islands. Four of the five protected areas are marine: the Hawar Islands, Mashtan Island, Arad Bay and Tubli Bay.

How the causeway tied Bahrain to Arabia

The King Fahd Causeway, opened in 1986, runs from Aziziyah, south of al-Khobar in Saudi Arabia, to al-Jasra west of Manama, on 536 concrete pylons. Britannica gives its length as 24 kilometres and Saudipedia, the Saudi reference work, as 25. A border post sits on an artificial island at its centre, split between the two countries, and Saudipedia records 382 million crossings between 1986 and 2018. A second fixed link, the Qatar-Bahrain Friendship Bridge, has been planned but not built.

The Hawar Islands, the one part of Bahrain close to another coast, were confirmed as Bahraini by the International Court of Justice on 16 March 2001. The same judgment drew a single maritime boundary between Bahrain and Qatar, and gave Janan Island to Qatar.