Pollution of Karun-Arvand Rood river system in Iran.
Karun River originates from the Zagres mountains and after travelling for 400 km enters into the Khuzestan plain. From this point on it winds its way through this flat alluvial plain until it reaches the Persian Gulf some 40 km south of Abadan. Upon entering Khuzestan plain Karun enjoys a good drinking quality. However after passing through a number of cities and towns whose sewage flow directly into the river, uptake for irrigation, and after collecting drainage water from large sugar cane plantations, its quality deteriorates significantly. Agriculture is by far the biggest user of the Karun river, consuming around 10 billion m3 per year. The returning drainage water from current agricultural projects account for 1.3 billion cubic meter of Karun's water. The last two major cities on this river are the port cities of Khoramshahr and Abadan whose entire 1.5 million population depends on this river for drinking water and their subsistence agriculture. The last decade of the 20th century witnessed a big upsurge in the expansion of agricultural and industrial use of Karun water. A push for achieving self-sufficiency in sugar production meant that several large irrigation-drainage projects were hurriedly planned and executed in areas with highly saline soils and near surface, highly saline ground water. The drainage system from one such project, Amir Kabir, has a flow rate of 6-8 m3s-1 and the EC of 45 to 70 dS/m. This practice, coupled with the drought of the last five years, meant that in the summer of 2000 river salinity in Khoramshahr and Abadan was so high that the water could no longer be used for drinking or even sanitary purposes. For the last 60 km of its route to Persian Gulf Karun is joined by the two Iraqi rivers of Euphrate and Tigris, thus forming a huge shipping waterway over which the two countries have gone to war a number of times. Excessive use of water by Iran and Iraq has reduced flow rate in this waterway to such extent that last year seawater entered Abadan's drinking water. Seawater encroachment has also put the future survival of the two country's huge date palm plantations on the banks of this shared waterway in jeopardy. Ecosystem of the region is very fragile and assault on this ecosystem by both Iran and Iraq is causing huge environmental, social and ecological problems. An investigation is under way to develop a long-term management plan for the reclamation and sustainable use of Karun river.
Proceedings of Environmental Science and Technology (2005)