The Aparan Reservoir is located in the central part of the town of Aparan, on the upper course of the Kasagh River, between the villages of Kuchak, Yeghipatrush, and the former village of Astvatsenkal.
It was built between 1962 and 1967 as an earthfill dam reservoir. It is one of Armenia's large reservoirs and was built for the purpose of using the water resources of the Kasagh River.
The reservoir's total volume is 91 million cubic meters, its surface area is 7.9 square kilometers, and its outflow capacity is 18 cubic meters per second. In 2014 the volume of water dropped to only 5–7 million cubic meters, far below the normal level. Over the course of its operation, the Aparan Reservoir has filled completely 9 times — in 1969, 1976, 1978, 1993, 2006, 2007, 2010, 2011, and 2026.
Whitefish and Sevan trout brought from Lake Sevan have been naturalized in the reservoir. The Church of Sts. Poghos-Petros (Peter and Paul) has been preserved within the flooded area.
