Shahid Rajaei Reservoir Dam is located 40KM south of Sari city in Mazandaran province. This dam was built on the Tejn River and its operation began in 1997. The main purpose of the dam is to provide water for agricultural/industrial sectors and also drinking water for Sari.

Energy production was a secondary goal. Therefore, the necessary facilities for a 13 MW power plant have been considered during the construction of the dam. This power plant is now operating with a maximum discharge of 18 cubic meters per second. Minimum flow rate of the power plant is about 1.65 cubic meters per second. Taking into account small water flow from the dam for agricultural use, it has been decided to establish a small power plant to fully utilize water energy.

From the dam to the Sari, there is 300m level difference. Hence, two more power plants have been designed in place of pressure breaker alongside of the drinking water pipes before entering Sari water treatment.