Water Research Inistitue. Water Research Inistitue. Abstract.
Water Research Inistitue
Sedimentation in dams reservoir is one of the main problems facing too many dams worldwide. According to the report published by International Committee of Large Dams (ICOLD), over 40,000 large dams exists in the world with a total storage capacity of 7,000 billion m3, operated for different purposes such as water supply, hydroelectric power generation and flood control. On the other hand, an average rate of 0.5 to %1 of their storage capacity is lost each year due to sedimentation. In order to compensate this reduction, between 300 and 400 large dams are required to be constructed each year. Presenting and applying appropriate treatment methods are strongly suggested to deal with this problem as well as paying special attention to the problem. Any neglect in this regard – esp. in arid and semi-arid regions like Iran – will result in more complicated situation and more problems regarding finding good solutions and is considered a real threat for future generations.
Over 42 large dams are now under operation in Iran with a total storage capacity of about 33,000 mm3. According to made measurements, yearly rate of sedimentation in dams reservoir in Iran is estimated 0.5 to %0.75 which is equal to 175 to 250 mm3 per year.
In other words, about 200 mm3 of capacity of dams reservoir in Iran is lost each year.
Some major dams in Iran and their specifications are presented in the following.
Storage capacity 7,000 Milliard m3
Average rate of sedimentation worldwide %0.5 - %1
Storage capacity 33,000 million m3
Average rate of sedimentation in Iran %0.75 - %1
Yearly rate of settled sediment in dams reservoir: 175 – 250 million m3
Grading from the viewpoint of the rate of yearly reduction of reservoir volume