GEOGRAPHY AND POPULATION
Saudi Arabia, with a total area of about 2.15 million 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 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 cultivable area has been estimated at 52.7 million 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 labour force compared with 6.5% in 1989. The share of 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.
TABLE 1 - Basic statistics and population
|Area of the country||1995||214969000||ha|
|Cultivable area||1992||52 684 000||ha|
|Cultivated area||1992||1 608 000||ha|
|- annual crops||1992||1 512 500||ha|
|- permanent crops||1992||95 500||ha|
|Total population||1995||17 880 000||inhabitants|
|Water supply coverage:|
TABLE 2 - Water: sources and use
|Renewable water resources:|
|Internal renewable water resources||2.4||km³/yr|
|Total (actual) renewable water resources||1995||2.4||km³/yr|
|Total (actual} renewable water resources per inhabitant||1995||134||m³/yr|
|Total dam capacity||1993||475||106 m³|
|- agricultural||1992||15308||106 m³/yr|
|- domestic||1992||1 517||106 m³/yr|
|- industrial||1992||193||106 m³/yr|
|Total water withdrawal||17018||106 m³/yr|
|per inhabitant||1992||1 040||m³/yr|
|as % of total (actual) renewable water resources||709||%|
|Other water withdrawal||-||106 m³/yr|
|Average groundwater depletion||1990||13558||106 m³/yr|
|Wastewater - Non-conventional water sources:|
|- produced wastewater||-||106 m³/yr|
|- treated wastewater||1991||454||106 m³/yr|
|- reused treated wastewater||1992||217||106 m³/yr|
|Desalinated water||1995||714||106 m³/yr|
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 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 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.
TABLE 3 - Irrigation and drainage
|1. Full or partial control irrigation: equipped area||1992||1608000||ha|
|- surface irrigation||1992||547 000||ha|
|- sprinkler irrigation||1992||1029000||ha|
|- micro-irrigation||1992||32 000||ha|
|% of area irrigated from groundwater||1992||95.6||%|
|% of area irrigated from surface water||1992||3.2||%|
|% of area irrigated from non-conventional sources||1992||1.2||%|
|% of equipped area actually irrigated||1992||100||%|
|2. Spate irrigation area||-||ha|
|3. Equipped wetland and inland valley bottoms (i.v.b.)||-||ha|
|Total irrigation (1+2+3)||1992||1608000||ha|
|- as % of cultivated area||1992||100||%|
|4. Flood recession cropping area||-||ha|
|Total water managed area (1+2+3+4)||1992||1608000||ha|
|- as % of cultivated area||1992||100||%|
|- increase over last 10 years||1982-92||170||%|
|- power irrigated area as % of water managed area||1992||95||%|
|Full or partial control irrigation schemes: Criteria|
|Large-scale schemes > 200 ha||1992||428 000||ha|
|Medium-scale schemes||1992||730 000||ha|
|Small-scale schemes < 5 ha||1992||450 000||ha|
|Total number of households in irrigation||1992||188 370|
|Total irrigated grain production||1992||4645424||tons|
|as % of total grain production||1992||100||%|
|Harvested crops under irrigation (full or partial control)||1992||1608000||ha|
|- permanent crops: total||1992||95 500||ha|
|- annual crops: total||1992||1512500||ha|
|. wheat||1992||907 300||ha|
|. fodder crops||1992||293 100||ha|
|. other cereals (mainly sorghum, barley)||1992||195 400||ha|
|. vegetables||1992||109 100||ha|
|. other annual crops||1992||7 600||ha|
|Drainage - Environment:|
|Drained area||1992||44 000||ha|
|as % of cultivated area||2.7||%|
|- drained areas in full or partial control irrigated areas||-||ha|
|- drained areas in equipped wetland and i.v.b||-||ha|
|- other drained areas||-||ha|
|- total drained area with subsurface drains||-||ha|
|- total drained area with surface drains||-||ha|
|Area salinized by irrigation||-||ha|
|Population affected by water-borne diseases||-||inhabitants|
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 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 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.
Figure 1 - Water withdrawal (total: 17 km³ in 1992)
Figure 2 - Origin of water used by all sectors (total: 16.3 km³ in 1990)
In 1992, total water withdrawal was estimated at 17 km³, of which 90% for agricultural purposes (Figure 1). 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 (Figure 2). 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 (Figure 3). 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 % (Figure 4).
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 (Figure 5).
The average cost for irrigation development is about $US I 093, 372 and 251/ha for microirrigation, sprinkler irrigation and surface irrigation systems respectively. Water is free of charge.
The cropped area has more than tripled between 1977 and 1992 (Figure 6). 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 (Figure 7). 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.
Figure 3 - Irrigation techniques f/p (total: 1 608 000 ha in 1992)
Figure 4 - Origin of irrigation water f/p (total: 1 608 000 ha in 1992)
Figure 5 - Typology of f/p control irrigation schemes (total: 1 608 000 ha in 1992)
Figure 6 - Evolution of the cropped area
Figure 7 - Irrigated crops f/t (total: 1 608 000 ha in 1992)
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 concretelined canals.
Soil salinity is being noticed in parts of the newly developed areas, due to poor irrigation water quality and thedrainage 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 programmes:
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 1985-91. 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 1991/92 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:
Extensive pumping of groundwater has resulted in a significant drop in the groundwater level (for example 100 metres 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 sea water 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.
MAIN SOURCES OF INFORMATION
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 [aloud. 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 1. 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.