Geography and Population
Saudi Arabia, with a total area of about 2.15 million square kilometers (km2), is by far the largest country in the Arabian Peninsula. It is bordered in the north by Jordan, Iraq, and Kuwait, in the east by the Persian Gulf with a coastline of 480 kilometers (km), in the south-east and south by Qatar, the United Arab Emirates, Oman, and Yemen, and in the west by the Red Sea with a coastline of 1,750 km.
It can be divided into 4 main physiographic units:
- the Western Mountains, called the Arabian Shield, with a peak at 2,000 meters (m) above sea level and crossed by deep valleys;
- the Central Hills, which run close to the western mountains and lie in the center of the country. Their elevation ranges between 900 and 1,800 meters above sea level;
- the Desert Regions, which lie to the east of the Central Hills, with elevations ranging between 200 and 900 meters. Sand dunes are commonly found in these deserts;
- the Coastal Regions, which include the coastal strip along the Red Sea with a width of 16 to 65 km. The important part is the Tahama Plain in the south. The plain on the eastern side overlooks the Persian Gulf. is generally wide and includes the region of oases.
The cultivable area has been estimated at 52.7 million hectares (ha), which is almost 25% of the total area. In 1992, the cultivated area was 1,608,000 ha, of which 1,512,500 ha consisted of annual crops and 95,500 ha consisted of permanent crops.
The total population is 17.9 million (1995) of which 20% is rural. In 1992, about 73% were estimated to be Saudi nationals. The natural demographic growth rate of Saudi nationals is probably over 3% and structurally the age of the population is very young, with 62.6% aged under 24 years in 1995, according to World Bank estimates. In 1994, agriculture employed 5.5% of the labor force compared with 6.5% in 1989. The share of Gross Domestic Product (GDP) accounted for by agriculture, which was 8.8% in 1993, has risen since the early 1980s, mainly as a result of the decline in revenue from the petroleum sector and government efforts to pursue a policy of greater self-sufficiency in agriculture.
Climate and Water Resources
Saudi Arabia falls in the tropical and subtropical desert region. The winds reaching the country are generally dry, and almost all the area is arid. Because of the aridity, and hence the relatively cloudless skies, there are great extremes of temperature, but there are also wide variations between the seasons and regions. In the central region, the summer (May to October) is overwhelmingly hot and dry, with maximum temperatures of over 50°C, while the winter is dry and cool with night-time temperatures close to freezing. There can be severe frost generally and even weeks of snow in the mountains. The western and eastern regions are hot and humid in the summer months, with maximum temperatures around 42°C, while the winters are warm.
In the north, annual rainfall varies between 100 and 200 millimeters (mm). Further in the south, except near the coast, annual rainfall drops below 100 mm. The higher parts of the west and south do, however, experience appreciable rainfalls and over some small areas 500 mm/year is not uncommon. Total precipitation has been estimated at 126.8 km3/year, which is equal to 59 mm/year over the whole country.
Heavy rainfall sometimes results in flash floods of short duration. River beds are dry for the rest of the time. Part of the surface runoff percolates through the sedimentary layers in the valleys and recharges the groundwater, some is lost by evaporation. The largest quantity of runoff occurs in the western region, which represents 60% of the total runoff although it covers only 10% of the total area of the country. The remaining 40% of the total runoff occurs in the far south of the western coast (Tahama) which covers only 2% of the total area of the country. Total surface water resources have been estimated at 2.2 cubic kilometers per year (km3/year), most of it infiltrating to recharge the aquifers. About 1 km3 recharges the usable aquifers. The total (including fossil) groundwater reserves have been estimated at about 500 km3, of which 340 km3 are probably abstractable at an acceptable cost in view of the economic conditions of the country.
In 1993, approximately 185 dams of various sizes had been constructed for flood control and groundwater recharge with a combined storage capacity of 475 million cubic meters (m3). About 45 new dams were planned to be built. A major dam, the Bisha dam in the south-west with a capacity of 325 million m3, was under construction in 1993.
Desalinated Water and Treated Wastewater
Saudi Arabia is the largest producer of desalinated water from the sea. In 1992, there were 18 desalination and power plants in the western coast, with a total capacity of over 0.7 million m3/day of water and 1,286 megawatts (MW) of electricity, and four plants on in the east coast, with a total capacity of over 1.1 million m3/day of water and 1,550 MW of electricity. Moreover three plants were under construction and two plants under bidding. In 1992, actual desalinated water production was about 675 million m3.
Some 265 million m3 were produced on the western coast, of which over 50% was exported to the city of Jeddah, while 410 million m3 were produced on the eastern coast, of which over 65% was exported to the city of Riyadh, which is located about 400 km from the sea. The total length of pipelines used for the transmission of desalinated water is about 3,722 km. The capacity of desalinated water reservoirs amounted to 1.85 million m3. In 1995, desalinated water production was 714 million m3.
In 1991, there were 22 sewage treatment plants in operation (10 of them being waste stabilization ponds) with a total wastewater treatment of 1.2 million m3/day or 454 million m3/year. Five new plants were being designed and the 22 existing were proposed for upgrading/extension in order to have a total flow of 1.8 million m3/day by the year 2000. In 1992, 217 million m3 of treated wastewater were reused.
In 1992, total water withdrawal was estimated at 17 km3, of which 90% for agricultural purposes (8.9% is withdrawn for domestic use and 1.1% for industrial use). In 1990, total water withdrawal was estimated at 16.3 km3. Desalinated water is used for municipal purposes, as it is too saline, even after treatment, for irrigation. Treated wastewater is used to irrigate non-edible crops, for landscape irrigation and for industrial cooling. However, most of the water used (> 13.5 km3) comes from non-renewable, deep aquifers. At the 1990 rate of abstraction, it is estimated that the usable reserves will last for a maximum of 25 to 30 years. The quality of the abstracted water is likely to deteriorate with time because of the flow from low quality water in the same aquifers towards the core of the depression at the point of use. In 1988, there were 4,667 multi-purpose government wells and 44,080 multipurpose private wells.
Irrigation and Drainage Development
The most recent soil surveys (1989) and classifications put the area of land suitable for irrigated agriculture at about 10 million ha. However, as shown above, the limiting factor is water. At present, depletion of non-renewable fossil water is already taking place at a very fast rate.
All agriculture is irrigated and in 1992 the water managed area was estimated at about 1.6 million ha, all equipped for full/partial control irrigation. Surface irrigation is practiced on the old agricultural lands, cultivated since before 1975, which represent about 34% of the irrigated area. Sprinkler irrigation is practiced on about 64% of the irrigated areas. The central pivot sprinkler system covers practically all the lands cropped with cereals. Normally, pumped groundwater from one deep well supplies one or two central pivots. The irrigation application efficiency of this method is estimated at between 70 and 85%. Vegetables and fruit trees are in general irrigated by drip and bubbler methods respectively. Groundwater is used on almost 96% of the irrigated area, treated wastewater on 1%.
In 1992, 428,000 ha were estimated to be cultivated by 1,070 large farms, with an area of more than 200 ha each. The total area of medium farms (5 - 200 ha) was 730,000 ha, comprising 7,300 farms. Small farms ( < 5 ha) covered 450,000 ha, comprising 180,000 farms.
The average cost for irrigation development is about $US 1,093,372 and 251/ha for micro-irrigation, sprinkler irrigation and surface irrigation systems respectively. Water is free of charge.
The cropped area has more than tripled between 1977 and 1992. In general, there is only one cropping season. The major irrigated crop is wheat. In 1988, it consumed almost 40% of the total quantity of irrigation water while it covered almost 62% of the irrigated area. Other major crops are fodder, other cereals (particularly sorghum and barley), fruit trees, and vegetables. Since 1988, self-sufficiency in wheat has been reached and part of the production is being exported. In 1992, wheat production was almost 4.1 million tons, while national demand was only about 1.2 million tons. Vegetables, fruits and dates, and fodder are also exported.
Waterlogging, Drainage, and Salinity
Waterlogging and drainage problems occur in the central and southern parts of the country, due to the existence of shallow, impervious layers. About 44,000 ha, or 2.7% of the irrigated area, have drainage facilities. The drainage systems mainly consist of open drainage canals. In several projects, such as the Al-Hassa irrigation project in the east, agricultural drainage water is reused for irrigation after blending with fresh groundwater. Old irrigation networks are replaced with concrete lined canals.
Soil salinity is being noticed in parts of the newly developed areas, due to poor irrigation water quality and the drainage conditions of some soils.
The Ministry of Agriculture and Water (MAW) is in charge of water resources research, drinking water supply, construction, and the operation and maintenance of water resources projects.
The Agency of Water Affairs within MAW has three main programs:
- water resources development, which includes all activities related to geological and hydrological studies, wastewater reuse investigations, well drilling, and dam construction, and the preparation of the national water plan;
- drinking water supply, which includes the construction of drinking water supply networks to various towns and cities that do not have local water authorities or municipalities;
- the operation and maintenance program. On-farm management is the farmers responsibility, but problems affecting more than one farmer (common irrigation networks, drainage, pest control, etc.) are under the responsibility of the Ministry.
The General Organization for Desalination of MAW is responsible for the construction, operation, and maintenance of desalination plants.
The Al-Hassa Irrigation and Drainage Authority (HIDA) is part of MAW and is in charge hydrological studies and data collection to improve the use of water for irrigation. It is also responsible for irrigation water conservation, estimation of crop water requirements, irrigation water distribution to the farms and the operation and maintenance of irrigation and drainage canal systems in the irrigation schemes managed by MAW.
The Ministry of Municipal and Rural Affairs is responsible for the construction, operation, and maintenance of drinking water supply networks and for the installation of water connections at house level. It is also responsible for the construction, operation, and maintenance of wastewater treatment plants.
Trends in Water Resources Management
In 1981 there began a change in agricultural cropping patterns by adopting new technologies, exercising extensive and effective agricultural extension, using improved seed varieties with high productivity and providing advanced plant protection services in line with modern agricultural methods.
The government's involvement in the agricultural sector has been extensive. During the 1980s food self-sufficiency, particularly in wheat and dairy products, became a major priority and, with the support of heavy subsidies, the added value in agriculture increased by more than 70% in the period 1985-1991. Wheat production was even sufficient to enable Saudi Arabia to become the world's sixth largest wheat exporter. However despite its success, this policy is a threat to the country's water reserves. On economic grounds, the 1991/1992 harvest was estimated to have cost the government around $US 480/ton compared with world prices for wheat of $US 100/ton. At present, the national goal is the diversification of agricultural production in order to meet the growing demand for other types of crops and to adjust the wheat production to the level of annual national consumption.
Because of the development of agriculture, which is by far the largest water user, the depletion of fossil groundwater takes place at very fast rates. It is expected that at the present rates of abstraction all the reserves will be used within the next 25 to 30 years. The Ministry of Planning has proposed a target to reduce annual irrigation water use from the current 15.3 km3 to 14.7 km3 by the year 2000. Measures to be taken are:
- implementation of effective irrigation schedules at farm level to deliver irrigation water according to actual crop need, which is expected to result in a saving of water of at least 30%;
- replacement of surface irrigation systems by sprinkler irrigation and micro-irrigation systems;
- shifting of some of the fodder and cereals areas from high water consumption zones to lower water consumption zones and cultivation of crops with lower water requirements;
- introduction of water meters at farm level to control the pumping of water.
Extensive pumping of groundwater has resulted in a significant drop in the groundwater level (for example 100 meters in the north-west in the last decade), requiring deeper and larger holes to be drilled and a higher head for pumping which results in a higher production cost. Groundwater quality has also deteriorated to the point where it can no longer be used for municipal supply without expensive treatment. Furthermore, only half the groundwater reserves are located near the areas of demand. The coastal areas suffer increasingly from seawater intrusion.
While Saudi Arabia is already by far the largest producer of desalinated water, future development will have to depend even more on the development of this source and on the reuse of treated wastewater. However, as up to present the desalinated water is still too saline for agricultural use, the problem of the rapid depletion of fossil water is still a long way from being solved.
- Abdallah E. Dabbagh and Wali A. Abderrahman. 1996. Management of groundwater resources in Saudi Arabia under various irrigation water use scenarios. In: Arabian Journal of Science and Engineering.
- Ali A. Al Jaloud. 1991. Agriculture and fertilizer use in Saudi Arabia. Research Institute of Natural Resources and Environment. Country paper for expert consultation on fertigation/chemigation, Cairo, Egypt, 8-11 September 1991.
- Department of Economic Studies and Statistics. 1989. Agricultural Sector Development: Graphical Indicators. Ministry of Agriculture and Water.
- Ministry of Agriculture and Water. 1992. Agricultural statistical yearbook.
- Munther J. Haddadin, Director of the Regional Office for Integrated Development. 1990. Progress of the Implementation of the Mar del Plata Action Plan in the Region of the Near East and North Africa; Country: Saudi Arabia. UNDTCD [United Nations Department of Technical Cooperation for Development].
- National Irrigation Department. 1988. Wastewater reuse for agricultural purposes. Ministry of Agriculture and Water.
- Saline Water Conversion Corporation. Annual Report 1992.
- Walid A. Abderrahman. 1994. Advanced and modern efficient irrigation technology in the Arab World.
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