THE CANYON OF THE RIVER JERMA
The river Jerma (Sukovska reka) is the left tributary of the river Nisava, and its length is 72 km. It has its headwaters east of Vlasinsko lake, where the river Vucja Reka presents its source branch. After 17 km it enters the region Znepolje in Bulgaria (the river is also known as the river Trnska reka). Then it flows across Bulgarian territory for 27 km, and it enters Serbia again near the village Petacinci in the municipality of Dimitrovgrad , where it flows mainly northwards for about 28 km, until it empties into the river Nisava near the village Sukovo (11 km away from Dimitrovgrad).
The gorge of the river Jerma had been formed during the Tertiary period, after the regression of the Senon Sea (about 65 million years ago), and complex and long-lasting changes of the initial paleorelief. The forming of the today appearance happened in the Plicene and Pleistocene phase as a result of the combined effect of tectonic activities, water erosion, denudation and karst processes. That is when the river Jerma was formed.
In the region of Derekul, the riverbed of the river Jerma is wide in the extensions, and very narrow in the gorge. The water flows through the gorge with a roaring sound, it makes its way near huge blocks, or throws down them, whirls and foams. In the wider part of the riverbed, the depth of clear water amounts to several dozen centimeters, and about two metres in the gorge during the summer. The water level is considerably higher during the winter when snow melts. Flowing through Mount Greben (1337 m) and Vlaska Mountain (1442 m), the river Jerma builds two huge ravines which are commonly known as Odorovsko and Vlasko zdrelo (gorge), and whose sides are 300-400 m high and 10-30 m wide. The ravines had been completely impassable until 1927. A narrow-gage railway route was built at that time (for the needs of the coalmine ‘Rakita'). The mine was closed during the 60s of the previous century, and an asphalt road replaced the route during the 70s.
A narrow-gage railway route was built at that time (for the needs of the coalmine ‘Rakita'). The mine was closed during the 60s of the previous century, and an asphalt road replaced the route during the 70s.
