Dreding Projects In Iran and Environmental Management Aspects of Dredged Materials

The dredging industry in Iran, despite some difficulties, has been growing during the last two decades, The volume of the dredged materials has increased from 1 million cubic meters in 1979 to 10 million cubic meters 1999. However, the issues related to the management of the dredged materials, especially from environmental viewpoints, have not yet been considered. Statistics show between 10 to 25 percend the dredged materials all around the world are contaminated either by organic matters such as oil constituants and various types of hydrocarbons or mineral matters such as heavy metals. There is not much data present on these in Iran, although some analysis on the samples of dredged materials taken from Imam Khomeini and Nowshahr ports indicate thet similar problems do exist in the Iranian ports. Environmental Management of dredged Materials is based on disposal on land or sea. Land Dosposal of the dredged sediments is carried out by discharging them into the areas surrunded by dikes or into landfills. The uncontaminated dredging materials can also used for beach nourishment, construction of artificial islands, or agricultural uses. On the other hand, offshore dosposal is discharging the dredged sediments in the sea, wherever the depth of water is 30 meters or more. if the materials are contaminated, they should be disposed in confined disposal facilities (CDF) in order to prevent possible environmental damage to the sea. Investigations show that the dredged materials from Iranian ports, harbors, and approach channels are mainly disposed in the sea. However, the dredged materials from inland waterways are disposed in the riverbanks. At this time, there are no specific regulations to follow for managment of the dredges sediments in Iran. Only in Balmanshir river a kind of temporary stabilization method is used for the silty sediments. In this paper, after reviewing the situation of the Iranian dredging industry, Solidification and Stabilization (S/S) methods for uncontaminated sediment are discussed. Also some methods for decontamination of the contaminated sediments are presented. Finally according to the Ecological and Environmental characteristics of the Iranian coastal area, suitable managements methods are discussed.