Name several accumulations on the treska

The Treska River is a river that runs between the Jakupica (Mokra Planina) massif and Suve Gora massif for most of its flow. Its flow starts near the town of Kichevo and ends in the Skopje valley where it enters the Vardar River.

On the lower flow of the river there's two accumulations made, the larger Kozjak which is also newer, and the smaller and older is Matka.  Both of the accumulations are used for production of electricity, but also for tourist purposes as they are both in very attractive locations where there's beautiful nature, and the accumulations are further complementing it.