General summary Near East Region

Salinization, drainage and environment

Arid areas are sensitive to salinization problems because the volume of rainwater dissolving the salts generated by the soil is low. By extracting water from the soil, evaporation and evapotranspiration tend to increase salt concentrations. Direct evaporation from the soil surface causes a rapid accumulation of salt in the top layers. When significant amounts of water are provided by irrigation with no adequate provision for leaching of salts, the soils rapidly become salty and unproductive. Water storage in the reservoirs, where evaporation is intense, tends to increase the salt concentration of the stored water. For all these reasons, the Near East is a region subject to salinization and the problem has been known and recognized for a long time. However, assessment of salinization at national level is a difficult enterprise and very little information on the subject could be found during the survey. Furthermore, no commonly agreed methods exist to assess the degree of irrigation-induced salinization. Figures on areas salinized by irrigation were available for only eight of the 29 countries. In the near future, more information on salinization will probably become available and strategies to improve the situation should be defined, as this has been recognized as a priority by most of the Near East countries. On average around 29% of the irrigated areas in the eight countries are reported as having salinization problems, varying from 3.5% in Jordan to over 85 % in Kuwait.

One of the measures necessary to prevent irrigation-induced waterlogging and salinization in arid and semi-arid regions is the installation of drainage facilities. Drainage, in combination with adequate irrigation scheduling, allows for the leaching of excess salts from the plant root zone. Figures on drained areas are available for 13 of the 29 countries. About 34% of the irrigated areas in these countries have been provided with drainage facilities, varying from 0.6% in Iran to over 90% in Egypt.

Over-extraction of groundwater leads to a lowering of the groundwater table and a deterioration of the groundwater quality due to sea water intrusion and/or the upward diffusion of deeper saline water. Using saline groundwater for irrigation may increase soil salinity. All the countries of the Arabian Peninsula are facing this problem as are the islands of Cyprus and Malta and the coastal zones of countries like Libya and Egypt. Also in Tunisia and Djibouti the groundwater used for irrigation is reported to be rather saline.

The Aral Sea basin

The Aral Sea is not included in the Near East Region. However, since most of the countries of the Aral Sea basin are part of the Near East Region, special attention has been paid to the Aral Sea basin, in view of its particular environmental problems related to water resources and irrigation. Due to the increasing need for water for irrigation in the Aral Sea basin, mainly from the 1950s onwards, the sea level continually fell as more water was diverted from its two major effluents, the Amu Darya and the Syr Darya. Between 1960 and 1965, its surface area shrank by more than half, from 64 500 km² to less than 30 000 km². At the same time, the level fell by 19 metres and its salinity tripled. Once the world's fourth largest lake, the Aral Sea has now lost so much of its water volume that what remains is contained in three separate highly saline lakes. The dry seabed exposed to weathering has increased soil salinization and desertification around the sea. It is estimated that since the 1970s dust storms yearly spread tens of millions of tons of dust and salt, polluted with pesticides, over the whole region. Traces have been found at a distance of more than 1 000 kilometres. Waterlogging is reported in large areas due to inefficient irrigation combined with insufficient or no drainage. In 1993, all five Aral Sea basin countries (Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan) signed an agreement to improve the situation in the basin, but so far progress has been slow due to the region's political and economic situation.

More information can be found in the regional overview of the countries of the Former Soviet Union, where a special section has been dedicated to the Aral Sea basin.

Thematic maps