Jezero Butoniga, reservoir near Pazin, Istria, Croatia

Jezero Butoniga is an artificial lake built in 1988 in a valley near Pazin in Central Istria. Fed by several streams, it holds water that is distributed through pipes to supply drinking water to surrounding towns and villages.

Built in 1988, this reservoir was created to meet the growing water needs of the Istrian region. Since its completion, it has become the main drinking water source for several towns including Pazin, Porec, and Rovinj.

The reservoir's water is treated because of trihalomethane levels before it reaches taps in Pazin, Poreč and Rovinj. A cycling trail circles the water surface, letting riders look down on the dam and the surrounding hills. The streams feeding the lake form silt banks where they enter during low water.

The reservoir is reachable by road, particularly from the scenic route between Kašćerga and Ukotići. Swimming and fishing are not permitted because the water is protected for drinking supply purposes.

The reservoir's dam sits on the former course of the Butoniga river, which still flows below the dam and joins the Mirna between Gradinje and Motovun. The catchment lies on Istrian flysch of sandstone and marlstone, and the shared boundary of Buzet and Pazin runs roughly through the middle of the dammed area.