The Regions of Saudi Arabia
Saudi Arabia has four major geographical regions. They are Nejd (Najd; "highland") in central Arabia; Hejaz (Ḥijāz; "barrier") along the upper Red Sea coast; Asir (‘Asīr; "rough terrain") along the Red Sea between Hejaz and Yemen; and the Eastern Province (al-Ḥasā or al-Aḥsā’; "sandy ground with water"), along the Persian Gulf.
The largest region is Nejd, with the cities of Riyadh (Riyāḍ), Anaiza, Ḥā’il, and Buraydah. Nejd is a plateau in the center of the peninsula rising 2,000 feet (600 meters) in the east and 5,000 feet (1,500 meters) in the west. It is isolated by a waterless desert, the Dahnā’, to the east; by two vast sand deserts, the Empty Quarter to the south and the Nafūd to the north; and by a mountain range separating it from Hejaz to the west. Daytime temperature in the summer can rise to 130° F (54° C) and plunge to nearly freezing in the winter. Night temperatures, however, even during summer, are comfortable. The central area of Nejd is known as al-Qaṣīm. Historically a region of oasis farming, it is now a primary producer of wheat.
The region of Hejaz stretches along the Red Sea from the Gulf of Aqaba south to Asir. Its coastal plain is separated from the interior highlands by the western mountain slopes. Winter rains provide water, making settlement of the highlands possible. Important cities are two Red Sea ports—Jiddah and the modern industrial city of Yanbu‘, which is the terminus of a transpeninsular oil pipeline—and the holy city of Medina, situated 2,500 feet (760 meters) above sea level in the interior highlands. Mecca, the holiest city of Islam and forbidden to non-Muslims, is on the western side of the escarpment dividing the coastal plain from the mountainous interior. The city of Tā’if, with its mountain location and cool temperatures, is a summer haven for residents of Mecca and the unofficial summer seat of government for the kingdom. The population of Hejaz is the most racially and ethnically mixed in the kingdom owing to centuries of pilgrimage traffic and its Red Sea ports.
Asir extends along the Red Sea littoral south of the Hejaz. It has a fertile western coastland, the Tihāmah, which receives up to 12 inches (300 mm) of rainfall a year; this is more precipitation than any other part of the kingdom. In the southwestern corner of the Tihāmah is the city of Jizan. The surrounding region consists of fertile plains, forests, mountains (the highest peak rising to 11,000 ft, or 3,350 meters), and 100 islands. Coffee beans, grains, and fruits are grown there. In the Tihāmah lowlands, malaria infection is endemic year-round. The mountains rising from the coastal plain are terraced for agriculture. In the interior, several peaks southeast of Mecca reach heights of over 8,000 feet (2,440 meters). The city of Najrān, located near the Yemen border, has a desert climate. Nevertheless, plentiful groundwater and the kingdom's largest dam have allowed for agriculture and further urban development. The main city is Abhā. The natural beauty of the Abhā district has prompted the government to establish national parks there, but it is among the poorest and least developed areas in the kingdom.
The Eastern Province extends south from Kuwait along the Persian Gulf coast and from the coast to the Dahnā’. Its oil is the main source of Saudi Arabia's national income. The area's sedimentary rock, gravel, and sand are oil-producing land formations typical of the Middle East. Annual precipitation is sparse, sometimes less than 4 inches (100 mm). Ras Tanura (Ra’s al-Tannūra) is the terminus for the pipeline from the Dhahran ( ahrān) oil fields; it is the largest oil-exporting port in the world. Dammām, is the name of the municipal area formed by the three adjoining towns of Dammām, Khobar (Khubar), and Dhahran. It is the terminus of a railroad to Riyadh and the departure point for the King Fahd Causeway (completed in 1982), which connects the kingdom with the island state of Bahrain.
Also located in the region are the oasis towns of Qa īf and Hofuf (Hufūf) and the city of Jubail. Once a tiny coastal village, Jubail was turned into an industrial city in the late 1970s and 1980s. The Ḥasā oasis is Saudi Arabia's largest oasis and a center for its Shī‘ī population. It had plentiful groundwater for agriculture, including date production, until overuse by industry began to deplete this resource and cause salinity. Northwesterly winds, called the shamāl, are prevalent during the late spring and early summer.
In the southern part of Saudi Arabia, extending eastward some 750 miles (1,200 km) from the borders of Asir to the Persian Gulf, is the immense desert called the Empty Quarter (Rub‘ al-Khālī). It is the largest continuous body of sand in the world and covers about 200,000 square miles (518,000 sq km). Parts of it are uninhabited except after infrequent rains, when the al-Murrah Bedouin move in to take advantage of the sparse pasturage.
Saudi Arabia has very few permanent sources of surface freshwater. Seasonal wetlands are found throughout the kingdom. They are fed by runoff from rainfall and are most commonly seen as dry riverbeds known as wādīs. A few perennial rivers are fed by mountain runoff. Underground geothermal, fossil-water springs in the southwest produce perennial wetlands. There are underground lake systems, sometimes connected to each other by underground channels. A few surface lakes have been created by the erosion and collapse of the roof over an underground lake. The largest surface lake, however, disappeared in the early 1990s owing to the overuse of underground water.
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Because of the scarcity of freshwater, Saudi Arabia must rely on deep aquifers and desalination plants on the Red Sea and Gulf coasts to provide for the needs of its growing population. Currently, 77.5% of the water produced in the kingdom comes from the ground, but this resource is rapidly being depleted as a result of increased consumption, especially by agriculture and industry. Twenty-five desalination plants provide the balance of water resources, including about 70% of the kingdom's drinking water. Even though Saudi Arabia is now the world's largest producer of desalinated water, the plants will have to be expanded and desalination technologies improved to meet future needs, estimated at 6 trillion cubic feet (170 billion cu meters) of water annually by 2020, compared with some 530 billion cubic feet (15 billion cu meters) in 2003.
Water for irrigation also comes from a network of 200 dams with a total reservoir capacity of 15.9 billion cubic feet (0.5 billion cu meters), including the Wadi Bisha dam, the second largest in the Middle East. Recycling plants in Jiddah and Riyadh treat urban wastewater for reuse.