The protected territory of 60 ha. Unique geological object - Karst sinkholes Ezernieki are earth sinkholes (approximately 1-6 m depth, 3-10 m in diameter), formed in areas where groundwater has washed out gypsum, creating voids in underground layers.

In the karst processes the ravines, funnel shape sinkholes and two lakes were formed - Vecezers and Linezers, where irregular water level fluctuations have been observed. Linezers sometimes behave quite strange - water partially or completely flows underground. Over the last decades, it has been observed that in Linezers, through about 9m deep funnel's water swallower, the water disappears partly or completely.