A Vision on Water Resources Situation, Irrigation and Agricultural Production in Iran

Land
Out of the total land area of the country of 165 million ha (Mha), 51 Mha is cultivable. However, the actual cultivated area of the country is about 19 Mha, or 36 percent of the cultivable area. An area of 12.4 Mha comprises forests while 89.2 Mha consists of pastures, mountains and deserts. The interior plateau lies in the central and eastern Iran and occupies about half of country’s total area.

Climate
Iran’s climate varies from region to region. While the winter temperatures in the mountainous areas of the north-west drop as low as -29oC, the Khuzestan Plain has extremely hot humid summer with an average temperature of about 35oC. Most of the interior plateau has a dry climate, but the winters are mild and pleasant. An average of about 50 mm of rain falls on the deserts yearly. The Caspian Sea Coast is Iran’s only region of abundant rainfall of 1600 mm per year. Iran has 8 climatic zones varying from very dry to very wet. The average rainfall in the country is 250 mm.

Water Resources
According to the water comprehensive plan of the country, the total annual precipitation throughout the country as the main water resources in Iran is equal to 413 billion cubic meters, of which 93 billion cubic meters flows as the surface water, 25 billion cubic meters penetrates to the mobile aquifers and the rest becomes inaccessible in the form of evapotranspiration from the surface of the land, forests, pastures & dry farming areas. Besides, water resources supplied through precipitation, about 12 billion cubic meters enters our country via rivers which make the total surface water resources reach 105 billion cubic meters.
Considering the 25 billion cubic meters of the underground mobile aquifers, the total renewable water resources of the country reaches 130 billion cubic meters.
The studies reveal that about 89.5 billion cubic meter of the total renewable water resources is used for the sectors of agriculture, industry, mines and home usage as the following:

Water Stress in Iran
Having insufficient and improper locational, as well as, periodical precipitation, we consider Iran among the arid & semi-arid countries of the world. Population increase, hygiene development, agriculture and industry extension, etc. increase the water demand, cause the widening gap between supply and demand of this valuable material in the future, and make the approach towards an economical planning for water resources, with an optimal allocation of funding, difficult.
Rapid population increase is the most important factor of per capita renewable water decrease in our country during the last 80 years. Iran’s population increased from 10 million in 1925 to 68 million in 2005, which are about 6.8 times as many as the previous 8 decades. The per capita renewable water resources (PCRWR) of the country were decreased from 13000 cubic meters in 1925 to about 1900 cubic meters in 2005.
Figure 1 and 2 illustrate the periodical trends of the population increase and PCRWR decrease. In figure 1, the trend of the population increase and in figure 2 the trend of the PCRWR decrease in the previous 80 years are clearly illustrated.

Reviewing the situation of Iran Water Resources, we use the 3 indicators of FALKEN-MARK, UN and IWMI for analysis. Tables 1 & 2 illustrate the specific conditions of such indicators:

Table 1, illustrates the specific conditions of such indicators

a: Country per capita renewable water
b: Ratio of Water Consumption to Renewable Water Resources

At present, Iran with 68.8 million population using 89.5 billion cubic meters out of 130 billion cubic meters of the Annual Renewable Water Resources (ARWR) has a PCRWR of 1900 cubic meters per year. Thus, Iran is at the water crisis threshold (WCT) according to the FAIKENMARK indicator. However, as 69 percent of the total ARWR is used, Iran is in a severe water crisis (SWC) situation according to the indicators of UN and the International Water Management Institute (IWMI).
Table 2, International Water Management Institute (IWMI) Indicator

I iwmi1: Percent of Present Water Withdrawal to Annual Renewable Water Resources.
I iwmi2: Percent of Future Water Withdrawal to Present Water Withdrawal.

Table 3, Analysis of Iran Water Resources

According to the IWMI report, Iran should increase 112 percent to its supply of water resources up to 2025 in order to maintain the present situation. Therefore, the authorities, managers and experts are required to make rational, applicable decisions to solve such abstrusity.

The Irrigation and Agricultural
Iran with an area of 165 million hectares has 37 million hectares arable land of which only 8 million hectares are irrigated, 6 million hectares are rain-fed, and 4.5 million hectare remain in the form of fallow land. From the total of 8.1 million ha of irrigated lands in Iran; 7.6 million ha (95%) are under surface irrigation and 0.4 million ha (5%) under the pressurized irrigation.
The agricultural sector plays a vital role in the national economy and food products of Iran. About 27 percent of GNP and 23 percent of Iran labour power are related to this sector. Although equal land areas are allocated for the irrigated and rain-fed farms, the irrigated farming is the basic factor of food production because of the improper locational and periodical precipitation, that is, about 89 percent of the total agricultural products in the last 5 years have been produced from the irrigated cultivation and rest (11 percent) produce from rain-fed (figure 3).

Figure 3, Comparing food production between irrigated and rain-fed agriculture in the world and Iran
The potentiality of Iran agricultural sector compared with the other countries of the world is fairly in a suitable situation. After India, China, US and Pakistan, Iran is ranked the fifth level in the irrigated farming area, however, in the 20th level, relevant the total arable land. Considering 8 million hectares of Iran irrigated area, that is about 118 hectare per 1000 persons, compared with 45 hectares of the Average World Irrigated Area (AWIA) per 1000 persons, Iran per capita area of the irrigated farming is about 2.5 times as many as the AWIA.