Lake Hafik

Hafik Lake, Büyük Lake or Koçhisar Lake, a small karst lake located north of the district of Hafik, belonging to Sivas in the Central Anatolia Region. It is 1100 m long, 1000 m wide, at an elevation of 1295 m, with an area of about 80 ha, and a depth of 2–6 m.

General characteristics

The lake is referred to as Büyük Lake on official maps, and because Hafik was a district named Koçhisar in the late Ottoman period, it is also called Koçhisar Lake. However, the name Hafik Lake is common in the region and in scientific publications. The lake is 1.5 km from the district center and 2.7 km from the Kızılırmak River.

The surface area of the lake is approximately 80 ha. Despite its small size, it is important because it is one of the few gypsum karst lakes found in Turkey. It formed in a depression carved in gypsum terrain, a rock type that dissolves easily like limestone and is widespread around the lake, and accumulated water. The lake lies in a karst basin surrounded by low hills.

Geomorphology

The area where gypsum karst is most common in Turkey is between Sivas and İmranlı. The dominant lithology of the region consists of Oligocene–Miocene aged gypsum layers. Light gray, mottled and white sandstone, as well as siltstone and conglomerate layers, are observed. The presence of wave marks in the gypsum–sandstone layers indicates that the terrain formed in a shallow water environment. The gypsum layers are covered by Quaternary alluvium.

The surrounding relief is formed by low ridges and the Hafik Plain. Between the dolines formed in the gypsum layers of the sedimentation area, there are melt-level ridges. To the west of the ridges the Hafik Plain is divided by an east‑west striking fault line. In the area gypsum has hydrated and expanded in volume, and a gypsum tectonics characteristic of the region has developed. Gypsum layers have risen over older layers along the fault, sometimes forming 90° slopes. Stream erosion and uplift have produced karstic forms. Karstification on gypsum develops faster than on limestone. This has caused a large number of karstic forms to appear in the region. Melt dolines with depths ranging from a few metres to several hundred metres are striking. Those containing water, such as East Lota Lake and West Lota Lake, are typical doline lakes.

Hydrography

The lake, located within the Kızılırmak basin, is at the same level as the river. The lake is fed by precipitation, springs and groundwater. The Sultanpınarı karstic spring in the lake’s catchment area is one of the sources feeding the lake. The waters used for irrigation no longer reach the lake. This has disturbed the lake’s hydrological balance. It is thought that the waters of the Mağaraönü cave reach the lake via a ditch. Another source feeding the lake is Sıtmapınarı.

The outflow of Hafik Lake drains into the Kızılırmak, therefore its waters are fresh. The lake experiences level drops due to drought.

Flora and Fauna

The lake contains freshwater fish such as mirror carp, yellow carp, crucian carp and black carp, as well as velvet fish, mullet and silver fish.

Transportation

The E 88 international highway connecting Erzincan to Sivas passes within 2 km, north of Hafik by 3 km. In 2006, 80 000 carp were stocked in the lake. The lake, one of Turkey’s 135 wetlands, hosts species such as reed bunting, crane, stork and wild goose. In the surrounding area, wild ducks such as fork‑tailed, long‑tailed, speckled and green‑head are hunted.