Water profile of Oman

Source: FAO
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Geography and population

The Sultanate of Oman occupies the south-eastern corner of the Arabian Peninsula and has a total area of 312,500 km2. It is bordered in the north-west by the United Arab Emirates, in the west by Saudi Arabia and in the south-west by Yemen. A detached area of Oman, separated from the rest of the country by the United Arab Emirates, lies at the tip of the Musandam Peninsula, on the southern shore of the Strait of Hormuz. The country has a coastline of almost 1,700 km, from the Strait of Hormuz in the north to the borders of the Republic of Yemen in the south-west, overlooking three seas: the Persian Gulf, the Gulf of Oman and the Arabian Sea.

Oman can be divided into the following physiographic regions:

caption Map of Oman. (Source: FAO)

  • The whole coastal plain. The most important parts are the Batinah Plain in the north, which is the principal agricultural area, and the Salalah Plain in the south. The elevation ranges between zero near the sea to 500 meters (m) further inland.
  • The mountain ranges, which occupy 15% of the total area of the country. The mountain range that runs in the north close to the Batinah Plain is the Jebel Al Akhdar with a peak at 3,000 meters. Other mountains are located in the Dhofar province, in the extreme southern part of the country, with peaks from 1,000 to 2,000 meters.
  • The internal regions. Between the coastal plain and the mountains in the north and south lie the internal regions, consisting of several plains with elevations not exceeding 500 meters

The cultivable area has been estimated at 2.2 million hectares (ha), which is 7% of the total area of the country. The cultivated area was 61,550 ha in 1993, of which 18,550 ha consisted of annual crops and 43,000 ha consisted of permanent crops. Over half the agricultural area is located in the Batinah Plain in the north which has a total area representing about 3% of the area of the country.

The total population is about 2.16 million (1995), of which 87% is rural according to United Nations (UN) estimates.

According to the national population census of 1993, 28% of the total population was rural. The difference between the two figures is explained by the fact that the UN standards for Oman consider as rural all the inhabitants of the country, except those of the two cities: Muscat and Matrah. The annual demographic growth rate is estimated at 3.7%. While agriculture and fisheries employed about 37% of the total labor force in 1993, they accounted for only 3.3% of gross domestic product (GDP).

Climate and water resources

Climate

The climate differs from one region to another. It is hot and humid during summer in the coastal areas and hot and dry in the interior regions with the exception of some higher lands and the southern Dhofar region, where the climate remains moderate throughout the year. In the north and center of Oman, rainfall occurs during the winter (November-April), while in the south and some internal parts of the country it is a result of seasonal summer storms (June-September). Average annual rainfall has been estimated at 55 mm, varying from less than 20 mm in the internal desert regions to over 300 mm in the mountain areas.

Water resources

A great deal of uncertainty lies in the assessment of Oman's water resources. Internal renewable water resources have been evaluated at 985 million m3/year. Surface water resources are scarce. In nearly all wadis, surface runoff occurs only for some hours or up to a few days after a storm, in the form of rapidly rising and falling flood flows. Since 1985, 15 major recharge dams have been constructed together with many smaller structures, in order to retain a portion of the peak flows, thus allowing more opportunity for groundwater recharge. In addition, several flood-control dams produce significant recharge benefits. In 1996, the total dam capacity is 58 million m3. Groundwater recharge is estimated at 955 million m3/year.

Non-conventional water sources

In 1995, the total produced wastewater was estimated at 58 million m3. Only 28 million m3 was treated, of which 26 million m3 was reused. Also in 1995, the quantity of desalinated water was 34 million m3.

Water withdrawal

In 1995, total water withdrawal was 1,223 million m3, of which 93.9% for agricultural purposes (4.6% is withdrawn for domestic use and 1.5% for industrial use). The treated wastewater was reused mainly for the irrigation of trees along the roads, while the desalinated water was used for domestic purposes. At present, groundwater depletion is thus estimated at around 240 million m3/year.

Irrigation and drainage development

All agriculture in Oman is irrigated and since the 1970s the equipped area increased from about 28,000 ha to 61,550 ha in 1993, of which 34,930 ha, or almost 57%, is located in the Al Batinah province in the north. Although 2.2 million ha are considered to be suitable for agriculture, there are no figures on the irrigation potential, as no reliable data are available on groundwater availability in the deep aquifers. At present, groundwater depletion already takes place, especially in coastal areas, leading to seawater intrusion and a deterioration in water quality.

The falaj system ('aflaj' in the plural) is the traditional method developed centuries ago for supplying water for irrigation and domestic purposes. Many of the systems currently in use are estimated to be over a thousand years old. The falaj comprises the entire system: the source, which might be a qanat, a spring or the upper reaches of flowing wadis from which water is diverted; the conveyance system, which is usually an open-earth or cement-lined ditch; and the delivery system. The falaj has assumed social significance, and well established rules of usage, maintenance and administration have evolved.

Originally, the falaj developed where higher-elevation water sources such as springs, qanats or surface water could be intercepted by diversion or small catchment dams and then conveyed by gravity to the point of use. More recently, however, dug wells have been used to supplement the falaj water. This is especially the case in the coastal areas where many hand-dug wells and tubewells have been constructed. For 47% of the total number of 62,411 households involved in irrigation, wells are now the main source of water, 39% rely on falaj water, while the remaining 14% have access to both sources.

Of the total area of 61,550 ha equipped for irrigation, all of which is power-irrigated using groundwater (wells, falaj), only 1,640 ha, or 2.7%, benefit from sprinkler irrigation and 2,090 ha, or 3.4%, from micro-irrigation techniques. Although the Ministry of Agriculture and Fisheries (MAF) is making efforts to introduce modern irrigation techniques, the traditional flood system remains the most common irrigation technique. In order to encourage farmers to take up the new techniques, MAF has approved a financial subsidy varying between 75% for small-scale schemes (less than 10 feddans or 4.2 ha), 50% for medium-scale schemes and 25% for large-scale schemes (more than 50 feddans or 21 ha). Most of the area consists of small schemes.

In 1996, the cost of irrigation development was estimated at US$3,250/ha for medium and large schemes and US$4,415/ha for small schemes. These costs represent the average cost of installing sprinkler irrigation and micro-irrigation systems. The average annual operation and maintenance costs are US$845, 1,170 and 1,820/ha for large, medium and small schemes respectively.

Date palm is the main crop grown in Oman, occupying about half the total cropped area. Other crops are fodder crops (mainly alfalfa), other fruit trees (citrus, bananas, mangoes, coconuts) vegetables and cereals (mainly barley, wheat and sorghum).

No reliable information on the area salinized by irrigation is available. A study done in 1994 on the salinity of soils in general in Oman, states that an area of 11.7 million ha, which is 35% of the total area of Oman, is affected by salinity. No drainage is practiced.

Institutional environment

Until May 2001, the Ministry of Water Resources (MOWR) was in charge of water resources assessment, whereas the Ministry of Agriculture and Fisheries (MAF) was in charge of irrigation. However, in May 2001, the Ministry of Water Resources was cancelled and its activities were transferred to the Ministry of Regional Municipality and Environment and Water Resource.

In 1988, Royal Decree No. 83/88 declared the water resources of Oman a national resource. This is the most far-reaching and important piece of legislation on water resources. Oman has several laws on water resources and the main measures taken for water management and conservation are:

  • no wells may be constructed within 3.5 km of the mother well of the falaj;
  • permits are required for the construction of new wells, for deepening existing wells, for changes in use and for installing a pump;
  • all drilling and well digging contractors are required to register with MWR on a yearly basis;
  • MWR has the cooperation of other government agencies such as the Ministry of Interior and the Royal Oman Police in dealing with offenders.

Trends in water resources management

Three broadly-based programs have been set up by the government for:

  • the improvement of data collection;
  • a detailed assessment of the water resources;
  • a study of water demand and its spatial distribution.

In addition to the above measures taken for water management and conservation, the government has recently initiated programs to relocate some of the large-scale farms in the Batinah and Salalah Plains, where the water resources are over-utilized, to areas with underutilized water resources. Several water conservation initiatives have been developed, like leakage control in municipal water supply schemes and the improvement of irrigation methods through subsidy programs. Public awareness of water resources issues has created a general and focused understanding of the overall situation and of the specific contribution each citizen can make.

The main issues and strategies that the government will address in the coming years are:

  • creating and cultivating conservation awareness;
  • matching water use to water availability;
  • establishing an integrated program for the conservation and management of the resources at basin level;
  • controlling saline intrusion by reducing abstraction below the long-term recharge;
  • adopting improved irrigation techniques and selecting appropriate crops to reduce agricultural water use;
  • controlling urban water losses;
  • increasing the use of treated wastewater and desalinated water;
  • protecting the groundwater resources in qualitative as well as quantitative terms;
  • constructing new groundwater recharge dams.

Further Reading

  • Improve and Development of Irrigation Water Management in aflaj system, Salim Al-Mamari, 2002
  • Department of Agricultural Statistics. 1995. Agricultural Census 1992-93. Ministry of Agriculture and Fisheries.
  • Ministry of Agriculture and Fisheries. [?]. Development and optimization of the use of water resources in the Sultanate of Oman.
  • Ministry of Water Resources. 1991. National Water resources Master Plan, Oman.
  • World Bank. 1988. Sultanate of Oman: Recent economic developments and prospects. Report No 6899-OM. Washington DC.



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Citation

(2007). Water profile of Oman. Retrieved from http://www.eoearth.org/view/article/51cbef307896bb431f69cfc3

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