Sioni reservoir is a reservoir in eastern Georgia on the middle course of the Iori River, laid out between the townlet of Sioni and the village of Lelovani. It occupies the floor of the Sioni basin. The reservoir is of valley type, its bed covered with recent alluvium. The right bank is steep and rocky, mantled with thick colluvium and subject to landslides; the left bank is gentle. The upper parts of the shore slopes are clothed in deciduous forest, the lower parts bare of trees. It is fed mainly by the Iori and is intended for the long-term regulation of the river's flow.