The dam site lies 40 Km northwest of Darehshahr County and 106 Km southeast of Ilam City. The Seymareh River running at a slope of 0.3% and 417 Km in length is formed by the confluence of the Gharesu and Gamasyab rivers. Chardavol and Shirvan rivers are the most important tributaries of the Seymareh River.
The Site investigation studies for the Karkheh tributaries were conducted by Mahab Ghodss in association with Electroconsult in 1990. And three construction sites were considered, namely Tang Sazbon, Tang Kafe Nila or Kafan Dehla (Seymarh Dam), and Tang Pa’alam for the preliminary studies. The preliminary studies began in December 1993 and ended in 1996. The phase II studies were assigned to Mahab Ghodss in July 1997 and were completed in 1999, and then they were approved by the Owner’s technical assistant and the technical committee of Water and Power Company. The construction supervision was assigned to Mahab Ghodss Consulting Engineering Company. The concreting of the dam body began in early 2007, and the reservoir began to be filled in April 2011. The commissioning tests of the power plant units were conducted in mid 2025.
Dam Type | Double-Curvature Concrete Arch Dam |
Dam Height from Foundation (m) | 180 |
Dam Crest Length (m) | 202 |
Dam Crest Width (m) | 6 |
Dam Body Volume (m3) | 1,033*۱۰³ |
Total Reservoir Capacity (m3) | 2,845 *۱۰⁶ |
Active Reservoir Capacity (m3) | 1,750 *۱۰⁶ |
Average Annual River Discharge (m3) | 84 *۱۰⁶ |
Spillway Type | Gated Side Spillway & Free Spillway |
Discharge Capacity of Spillways (m3/s) | 8,370 |
Powerhouse Type | Surface |
Number of Units | 3 |
Installed Capacity (MW) | 480 |
Average Annual Energy Generation (GWh) | 684 |