The gypsum karst units which are spread over a large area in the vicinity of Sivas, and especially in the east of Sivas, are presumed to be of Miocene age. Geomorphological features include numerous collapse dolines. The Seyfe and Goydun springs have high discharge rates of water of unsuitable quality (EC: 13,000 mho/cm). Lakes are formed in the collapsed gypsum areas and the water quality of these lakes is poor (Hafik lake, Todurge lake, Western Lota lake, Eastern Lota lake, etc.). The water quality of the Kizilirmak River, part of which is in this region, is not good enough for drinking water or irrigation.