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The Islamic Republic of Iran covers a total area of about 1.65 million km and is bordered by Azerbaijan, the Caspian Sea and Turkmenistan to the north, Afghanistan and Pakistan to the east, the Gulf of Oman and the Persian Gulf to the south, and Iraq and Turkey to the west. About 52 % of the country consists of mountains and deserts and some 16% of the country has an elevation of more than 2 000 m above sea level. The largest mountain massif is that of the Zagros, which runs from north-western Iran first southwards to the shores of the Persian Gulf and then continues eastwards till the most south-eastern province. Other mountain ranges run from the north-west to the east along the southern edge of the Caspian Sea. Finally, along the eastern frontier of Iran several scattered mountain chains exist. The Central or Interior Plateau is located in between these mountain chains and covers over 50% of the country. It is partly covered by a remarkable salt swamp (kavir) and partly by areas of loose sand or stones with stretches of better land near the foothills of the surrounding mountains.

The cultivable area is estimated at about 51 million ha, which is 31% of the total area. In 1993 about 18.5 million ha, or 36% of the cultivable area, were considered usable for agriculture, while 14.4 million ha were actually cultivated. Of this area, 12.8 million ha consisted of annual crops and 1.6 million ha of permanent crops. About 70 % of the landholders possess less than 5.5 ha (of which on average 2.13 ha irrigated and 3.25 ha rainfed).

TABLE 1 - Basic statistics and population

Physical areas:
Area of the country 1995 164800000 ha
Cultivable area 1993 51 000000 ha
Cultivated area 1993 14 382 418 ha
- annual crops 1993 12 732 418 ha
- permanent crops 1993 1 650 000 ha
Total population 1995 67 283 000 inhabitants
Population density 1995 41 inhab./km
Rural population 1995 41 %
Water supply coverage:
Urban population 1992 91 %
Rural population 1996 86 %

The total population is about 67.3 million (1995), of which 41% is rural. The average population density is 41 inhabitants/km, but it ranges from less than 10 in the eastern part of the country up to more than 150 in the Gilan province, located in the Caspian Plain in the north, which is by far the most densely populated region in the country. In the Tehran province, where the capital is located, the population density reaches 400 inhabitants/ km. The annual demographic growth rate was estimated at 3.4% over the period 1980-1990 and at 2.6% over the period 1990-1994. In 1991, agriculture employed around 29% of the total labour force and accounted for 21 % of GDP, while in 1992 it accounted for 23% of GDP. In 1989, agriculture accounted for 47% of non-oil exports.

TABLE 2 - Water: sources and use

Renewable water resources:
Average precipitation   252 mm/r
  415.3 km/yr
Internal renewable water resources   128.5 km/yr
Total (actual) renewable water resources 1995 137.51 km/yr
Dependency ratio 1995 6.6 %
Total (actual! renewable water resources per inhabitant 1995 2 044 m/yr
Total dam capacity 1993 39 200 106 m
Water withdrawal:
- agricultural 1993 64 155 106 m/yr
- domestic 1993 4 395 106 m/yr
- industrial 1993 1 484 106 m/yr
Total water withdrawal   70 034 106 m/yr
per inhabitant 1993 1 091 m/yr
as % of total (actual) renewable water resources   50.9 %
Other water withdrawal 1993 39 228 106 m/yr
Average groundwater depletion 1993 3 795 106 m/yr
Wastewater - Non-conventional water sources:
- produced wastewater 1992 4 409 106 m/yr
- treated wastewater 1992 219 106 m/yr
- reused treated wastewater   - 106 m/yr
Desalinated water 1991 2.9 106 m/yr



The climate of Iran is one of great extremes due to its geographic location and varied topography. The summer is extremely hot with temperatures in the interior rising possibly higher than anywhere else in the world, certainly over 55C has been recorded. In winter, however, the great altitude of much of the country and its continental situation result in far lower temperatures than one would expect to find in a country in such low latitudes. Minus 30C can be recorded in the north-west and minus 20C is common in many places.

Annual rainfall ranges from less than 50 mm in the deserts to more than 1600 mrn on the Caspian Plain. The average annual rainfall is 252 mm and approximately 90% of the country is arid or semiarid. Overall, about two-thirds of the country receives less than 250 mm of rainfall per year.

Water resources

Iran can be divided into the following major river basins: the Central Plateau in the middle, the Lake Orumieh basin in the north-west, the Persian Gulf and the Gulf of Oman in the west and south, the Lake Hamoun basin in the east, the Kara-Kum basin in the north-east and the Caspian Sea basin in the north. With an area of 424 240 km, the Caspian Sea is the largest landlocked water body in the world and its surface lies about 22 metres below sea level. The rainfall characteristics of the above basins are summarized in Table 4.

TABLE 3 - Irrigation and drainage

Irrigation potential 1995 15000000 ha
1. Full or partial control irrigation: equipped area 1993 7 264 194 ha
- surface irrigation 1993 7 173 494 ha
- sprinkler irrigation 1993 47 200 ha
- micro-irrigation 1993 43 500 ha
% of area irrigated from groundwater 1993 50.1 %
% of area irrigated from surface water 1993 49.9 %
% of area irrigated from non-conventional sources 1993 0.0 %
% of equipped area actually irrigated 1993 100 %
2. Spate irrigation area   - ha
3. Equipped wetland and inland valley bottoms (i.v.b.)   - ha
Total irrigation (1 + 2 + 3) 1993 7 264 194 ha
- as % of cultivated area   51 %
4. Flood recession cropping area 1993 10 000 ha
Total water managed area (1 +2+3+4) 1993 7 274 194 ha
- as % of cultivated area   51 %
- increase over last 10 years 1983-93 30 %
- power irrigated area as % of water managed area 1993 36.0 %
Full or partial control irrigation schemes: Criteria
Large-scale schemes > 50 ha 1991 708260 ha  
Medium-scale schemes 1991 3 159 924 ha
Small-scale schemes < 10 ha 1991 3 396 010 ha
Total number of households in irrigation 1991 2 620 000  
Irrigated crops:
Total irrigated grain production 1993 10000000 tons
as % of total grain production 1993 61 %
Harvested crops under irrigation (full or partial control) 1993 7 264 194 ha
- permanent crops: total 1993 1 564 884 ha
- annual crops: total 1993 5 699 310 ha
. wheat 1993 2 340 676 ha
. other cereals (barley and rice) 1993 1 256 310 ha
. fodder crops 1993 790 063 ha
. vegetables 1993 425 116 ha
. other annual crops 1993 887 145 ha
Drainage - Environment:
Drained area 1995 40 000 ha
as % of cultivated area   0.3 %
- drained areas in full or partial control irrigated areas 1995 40 000 ha
- drained areas in equipped wetland and i.v.b   - ha
- other drained areas   - ha
- total drained area with subsurface drains 1995 40 000 ha
- total drained area with surface drains   - ha
Flood-protected area   - ha
Area salinized by irrigation 1993 2 100 000 ha
Population affected by water-borne diseases   - inhabitants


TABLE 4 - Rainfall in the major basins in Iran

Basin Total area (km) As % of total area Rainfall (mm/year) Rainfall (km/year) As % of total rainfall
Central Plateau 832 000 51 165 138 33
Persian Gulf and Gulf of Oman 431 000 26 366 158 38
Caspian Sea 178 000 11 430 77 19
Lake Hamoun and Kara-Kum 150 000 9 142 21 5
Lake Orumie 57 000 3 370 21 5
Total 1 648 000 100 252 415 100

All these basins, except the Persian Gulf and Gulf of Oman, are interior basins. There are several large rivers, the only navigable one of which is Karun, the others being too steep and irregular. The Karun river, with a total length of 890 km, flows in the south-west of the country to the Shatt ElArab, which is formed by the Euphrates and the Tigris after their confluence. The few streams that empty into the Central Plateau dissipate into the saline marshes. All streams are seasonable and variable. Spring floods do enormous damage, while there is little water flow in summer when most streams disappear. Water is however stored naturally underground, finding its outlet in subterranean water canals (qanats) and springs. It can also be tapped by wells.

Internal renewable water resources are estimated at 128.5 km/year. Surface runoff represents a total of 97.3 km /year, of which 5.4 km/year comes from drainage of the aquifers, and groundwater recharge is estimated at about 49.3 km/year, of which 12.7 km/year is obtained from infiltration in the river bed. Iran receives 6.7 km/year of surface water from Pakistan and some water from Afghanistan through the Helmand river. The flow of the Arax river, at the border with Azerbaijan, is estimated at 4.63 km/year. The surface runoff to the sea and to other countries is estimated at 55.9 km/year. The total safe yield of groundwater (including non renewable water or unknown groundwater inflow from other countries) has been estimated at 49.3 km/year.


Dams have always played an important role in harnessing Iran's precious water reserves and the long-term objective of Iran's water resources development plan is based on the control and regulation of water resources through dams. In 1994, 27 storage dams were in operation with a total regulation capacity of 39.2 km. At the same time, 24 storage dams were under construction with a design regulation capacity of 11.5 km. In 1993, the annual electricity production from dams was 25 116

GWH, which is 33 % of the total energy production of the country. Dams also play an important role in flood control through routing of floods. Several reservoirs behind the dams seem to offer good sailing and water-skiing facilities, but have not been used for recreation so far.

Water use

The total agricultural, domestic and industrial water withdrawal was estimated at about 70 km in 1993 (Figure 1). Although this is equal to 51% of the actual available renewable water resources, current annual abstraction from aquifers (from 49 km in 1990 up to 57 km in 1993) is already more than the estimated safe yield (46 km). Further to these 70 km, another 39 km of water is used annually, of which about 20 km for electricity production, 11 km for flood control, 2 km for environmental protection (control of downstream parts of rivers), while the remaining part is considered to be surplus water.

Figure 1 - Water withdrawal (total: 70.034 km in 1993)


The problem of water supply has been a constant preoccupation since the beginning of the country's history, thousands of years ago. Its inhabitants learnt to design and implement efficient techniques for harnessing limited water resources and for irrigation. Apart from the qanat, which was a major source of irrigation and domestic water supply for centuries, Iranians have in the past built dams of various types and weirs. Some of these head control structures, built as long as 1000 years ago, are still in good condition.

Agricultural land availability is not a major constraint in the development of Iranian agriculture. The major constraint is the availability of water for the development of these lands. The irrigation potential, based on land and water resources, has been estimated at about 15 million ha, or 29% of the cultivable area. However, this would require optimum storage and water use.

In 1993 out of 14 382 million ha of cultivated land 7 264 million ha, or 51 %, were equipped for full or partial control irrigation. Annual crops covered 5 699 million ha and permanent irrigated trees covered 1 565 million ha. In addition, flood recession cropping is practiced on an area of about 10 000 ha in the southwest (Figure 2).

Surface irrigation techniques are used on 98.75 % of the area equipped for irrigation and 1.25 % benefits from a pressurized irrigation system (Figure 3). About half the area is irrigated from groundwater, including spring water (Figure 4). According to the landholding and technologies which are used, the farming systems are grouped as: small farms (< 10 ha) 47%, medium size farms (10-50 ha) 43%, and large farms (>50 ha) 10% (Figure 5).

The cost of surface irrigation development varies from $US 2 300/ha for large to $US 2 500/ ha for medium and $US 2 600/ha for small schemes. Average operation and maintenance costs are estimated at $US 130, 175 and 60 per ha and per year respectively. The cost of micro-irrigation and sprinkler irrigation development is estimated at about $US 2 200 and 1 200/ha. The average price of water delivered to farmers by government is $US 0.2 to 0.8/ 1 000 m, while the cost of withdrawal of groundwater by the farmer is $US 5 to 9/1 000 m and the cost for regulating surface water in existing projects is $US 3 to 5 per 1 000 m. This means that the government heavily subsidizes delivered water, which is probably one of the main reasons for the low irrigation efficiency throughout the country.

Figure 2 - Distribution of the water managed area (total: 7 274 194 ha in 1993)

Figure 3 - Irrigation techniques f/p [total: 7 264 194 ha in 1993)

On-farm application rates in the country are rather high and in general irrigation has a low efficiency, % on average at national level. Major causes of inefficiency include: careless operation, poor maintenance, negligible water prices, fragmentation of responsibilities among different governmental agencies and inadequate training of farmers. Low irrigation efficiency causes waterlogging and salinization in the irrigated areas, which are a major problem in Iran. No comprehensive study has been undertaken regarding the extent of irrigation-induced salinity, but according to an estimate (ICID, 1977) for the year 1974 about 38% of the irrigated area had soils with considerable salinity and drainage problems. Over 2 million ha are estimated to be salt-affected anal or waterlogged at present.

By far the most important irrigated crop is wheat covering almost one-third of the total irrigated area, followed by irrigated fruit trees, covering one fifth of the total area (Figure 6). Other major irrigated crops are barley, rice, vegetables and nurses Wheat is also by far the most important rainfed crop covering 4.47 million ha, or almost two-thirds of the rainfed area. The yield for irrigated wheat was estimated at 2.78 tons/ha in 1993 against 0.95 tons/ha for rainfed wheat.

Figure 4 - Origin of irrigation water f/p (total: 7 264 194 ha in 1993)

Figure 5 - Types of f/p control irrigation schemes (total: 7 264194 ha in 1991)

Figure 6 - Irrigated crops f/p (total: 7 264 194 ha in 1993)


According to the water legislation, three ministries are in charge of water resources assessment and development:


Agriculture is one of the main priorities in national development plans. The annual increase in irrigated land over 15 years (1978-1993) was 3.8% along with a 4.4% annual increase for agricultural water supply. An increase of 500 000 ha of irrigated land and an increase of 10 km/year of agricultural water supply was planned in the second national five-year plan (19952000).

At present, a big gap exists between water delivery from the main canals and water application in the field. Compared to the large investments for water resources development, little has been done to improve irrigation water use at farm level. Water is delivered to old traditional irrigation canals and on-farm conveyance and the use of irrigation water is generally rudimentary and wasteful. The use of earth bunds, unlined canals and poor levelling combined with low water charges have resulted in very low levels of water conveyance and use efficiencies (30% as a national average) and caused the emergence of serious drainage problems.

A fundamental review of the organizational chart and institutional changes were made to improve this situation. Since 1992, the Deputy Ministry for Infrastructure Affairs of the Ministry of Agriculture created five departments: farm development, pressurized irrigation systems, water supply, hydraulic constructions and operation and maintenance.

The government policy includes:


Bureau of Information and Statistics. 1994. Agricultural Statistics Yearbook 1993. Deputy Ministry of Plan and Project, Ministry of Agriculture.

Bureau of Operation and Maintenance of Dams and Irrigation Networks. 1995. Water utilization in the year 1993. Deputy Ministry of Water Affairs, Ministry of Agriculture.

Deputy Ministry for Infrastructure Affairs. 1991. Summary of the social and agricultural economy of Iran. Ministry of Agriculture.

Keshavan, M.A. 1993. Improvement of farm level infrastructures. Deputy Ministry for Infrastructure Affairs. Ministry of Agriculture.

Shakiebie. 1994. Seventh Iranian National Seminar on Irrigation and Drainage. IRNCID, Ministry of Energy.

Statistical Centre. 1994. Yearly Statistical Book 1993. Plan and Budget Organization.

Water and Sewage Engineering Co. Situation of water and wastewater in the country in 1992. Ministry of Energy.

World Bank. 1993. Staff appraisal report: Irrigation improvement project. Report No. 11393-lRN.

Yekom Consulting Engineers. 1995. Cost of Irrigation and Drainage Projects - Tender Documents.

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