Račna Karst Field

The Račna Karst Field (pronounced [ˈɾaːtʃna]; Slovene: Radensko polje) is a karst field in the northern edge of the Lower Carniolan karst area, south of Grosuplje, Slovenia. It has rich natural and cultural value. Because of its ecological significance, it is anticipated that a nature park will be established there and that it will be included in the Natura 2000 program.

The Račna Karst Field is named after the settlements of Velika Račna and Mala Račna. The local adjective form radenski (as well as the demonym Radenc) are based on the older form of the settlements' name.

Researchers started studying the Račna Karst Field during construction of the railroad to Kočevje in 1893. During this period, several karst caves in the Ribnica–Kočevje karst region were discovered and explored. One of the pioneers of such research was Pavel Kunaver, who wrote about the area in 1922, as well as the photographers Bogumil Brinšek, Josip Kunaver, and Ivan Tavčar. The geographers Drago Meze and Ivan Gams wrote more detailed studies of the area in 1977 and 1986. The botanical features of the karst field were explored by Luka Pintar in 1991. The last major study was carried out in 2000 by the Fauna and Flora Cartography Center (Slovene: Center za kartografijo favne in flore), commissioned by the local municipality.

The Račna Karst Field lies in an area with Dinaric-oriented ridges; it is approximately 4 kilometers (2.5 mi) long and 1 kilometer (0.62 mi) wide, and has a total area of 4 square kilometers (1.5 sq mi). It lies at an elevation of 325 meters (1,066 ft).

The karst field has a bowl-like shape with a level floor and a distinctly higher margin, and water enters it from the karst underground. Many other karst features are present in the karst field, such as springs, sinkholes, and estavelles. The karst field has three different watercourses; the Dobravka River flows from a non-karst area, whereas Zelenka Creek and Šica Creek are true karst streams. Kopanj Hill, an isolated dolomite hill 70 meters (230 ft) high, rises in the middle of the karst field and is a unique example of such a feature in a Slovene karst area. The floor of the karst field is covered in alluvial clay 5 meters (16 ft) to 10 meters (33 ft) deep, deposited on relatively pure Jurassic limestone. Only a few patches of the surface are composed of Triassic dolomite, which is more or less impermeable. During the Pleistocene, the Račna Karst Field was a lake and water drained from it into the karst underground through what are now dry inflow caves higher on the slopes at the edge of the area. At that time, Kopanj Hill was an island in the lake.

...
Wikipedia