Trebišnjica
The Trebišnjica (Cyrillic Требишњица) is 93.8 km, the longest karst river in Europe (Ponornica) and also the second longest river in Herzegovina . It has a catchment area of around 2300 km² and an average water flow of 114 m³ / s. The entire course, like the catchment area of the Trebišnjica, runs in the high karst of the Dinarides in Bosnia and Herzegovina . A pronounced karst hydrological system is formed through underground karst reservoirs . So the Trebišnjica drains underground to the Neretva and through some strong karst springs, u. a. the ombla , straight to the Mediterranean. Due to a hydroenergetically advantageous location, a major hydroenergetic project is being carried out in the Trebišnjica catchment area by setting up accumulation in natural poljes, which were connected to each other with underground tunnels with a drop of several hundred meters. With the completion of the Gornji horizonti system and the completion of the Dubrovnik 2 and Dabar hydropower plants , the work that has been underway since 1965 will form one of the largest hydroenergetic systems in Southeast Europe. The river is already dammed in several places for drinking water and energy generation and is used hydroenergetically in its headwaters and in the adjoining gorge by two dams ( Bilećko jezero , Grančarevo). Dubrovnik gets its drinking water from the Trebišnjica through the gallery of the Grančarevo reservoir. During the Yugoslav war, the drinking water supply to Dubrovnik was interrupted by this water resource for several years. The Trebišnjica flows through the city of Trebinje . Behind the town it crosses the Popovo polje plain for 25 km before disappearing underground near Hutovo .
Run
The source streams of the Trebišnjica lie in the Bilečko Polje. They are fed by karst aquifers in the Phreatic zone from Fatničko polje. Several powerful karst springs with a discharge of 80 m³ / s are located near Bileća . You can no longer see them today because the Polje was dammed up to the Bilećko jezero . The eastern bank of the reservoir is now almost entirely in Montenegro , but the border was originally east of the former course of the river. Between Donje Grnčarevo and Lastva , the Trebišnjica bends westward into the Trebinjsko polje , where it is again dammed in a small dam near Gorica. Then flows along the southern slopes of the mountain range Bjelasnica through Trebinje and Dražin Do, Tvrdoš , Gornja Kocela and Donja Kocela before one of the most Karstpoljen ( Polje ) the Balkans , the Polje Popovo ( Priest field ) flows.
The Popovo polje
The Popovo polje is also a special landform within the Karst polje, which is explained in particular by its function as the most important hydrological node in the karst hydrological system of eastern Herzegovina. In its upper part it is covered by 1–2 m thick alluvial sediments, which grow to 15–20 m in the lower (western) part. In the Polje itself, 500 ponors, estavelles (periodic springs or ponors depending on the formation of the phreatic zone and the water inflow in the polje) and intermittent springs have been identified to date. Intermittent springs dominate the upper, Estavellen the middle and Ponore the lower polje area. The water loss of the Trebišnjica in Popovo polje is 63 m³ / s in the dry season. The total sinking capacity is over 300 m³ / s. The capacity of the last ponor (Doljašnica) alone is 60 m³ / s. In contrast, however, the winter inflow of 1000 m³ / s is substantially more important. The record on December 3, 1903 was 1362 m³ / s. The inundation of the Polje reaches 40 m at such high water levels and the former average flood time of the Polje was 253 days. After 62.2 km of the course of the river had got a concrete border and two reservoirs control the water supply, no more floods can be observed today.
In Popovo polje, the Trebišnjica originally seeped away directly behind Trebinje, but was channeled in a concrete bed in 1979 and flows past the villages of Staro Slano, Đedići, Dobromani, Žarkovo, Tilje, Sedlari, Grmljani and Zavala. At Zavala is the Vjetrenica cave, the largest in Bosnia and Herzegovina. Then it flows in a wide bend past the places Dvrsnica, Orašje, Čavaš and Turkovići and finally disappears in the lower Popovo polje, near the Croatian border, in several crevice-like infiltration points (the two most important: Doljašnica and Ponikva ). The water of the Trebišnjica reappears below the Popovo polje in three different places:
Karst hydrological catchment area
The Trebišnjica has a large karst hydrological catchment area in eastern Herzegovina .
This includes all karst water systems south of the Gatacko and Nevesinjsko poljes.
- the Mušnica , which crosses the Gatačko polje ( Gacko field ) plateau from east to west (from Lebršnik to Bjelašnica ), through the Klinje Lake and the towns of Avtovac , Gacko , Srđevići, Bašići, Drugovići, Kula and Branilovići before it flows it cuts into the karst in the Cerničko polje ( Cernica field ) and seeps into the ground west of the Baba mountain near the villages of Cernica and Ključ as Ključka rijeka ( Ključ river ).
- the Gračanica , which also flows from Čemerno near the places Bahori and Gračanica into the Gatačko polje and joins the Mušnica at Srđevići. Both source rivers change their direction of flow frequently and abruptly.
In the southern Fatničko polje ( Fatnica field ) the river reaches the surface again for a short distance and is called Fatnička rijeka ( Fatnica river ) there.
After about 30 km underground, the water of the Fatnička rijeka reappears in the form of several powerful springs near the town of Bileća . The source brooks unite a little later to form the actual Trebišnjica, the most important river in eastern Herzegovina, which flows from there through the Miruša Depression to the south. At the southern end of the Miruša Depression near Gornje Grnčarevo, the river to Bilećko jezero was dammed, the eastern bank of which is almost entirely in Montenegro .
Karst springs, Vruljen and Estavellen
- a series of underwater springs ( called vrulje , which means boiling water ) near the port of Slano in Croatia, northwest of the city of Dubrovnik .
- after 20 km underground, the Trebišnjica emerges as a powerful spring in the large cave near Komolac, a district of Dubrovnik, and feeds the Ombla river (also Umbla or Dubrovačka rijeka ; river of Dubrovnik ). The ombla is only unaffected at 20 meters from the sea. The estuary, which is sometimes incorrectly attributed to the river, as part of the Rijeka Dubrovačka bay in the Adriatic north of Dubrovnik, is 4.2 km long, quite wide and very watery with an average discharge of 24 m³ / s. The water depth in the estuary is up to 30 m. If the estuary is assigned to the Ombla, in contrast to all other sections of the Trebišnjica, it is navigable over a length of 3.7 km. Some districts of Dubrovnik ( Mokošica , Komolac, Rožat, Prijevor, Lozica) extend along the estuary of the river, whose water of the 20 m long upper course has been used in the waterworks of Dubrovnik since 1437.
Catchment area
The catchment area of the Trebšnjica covers a total of 4,926 km², of which about 600 km² also belong to the catchment area of the Neretva (Čapljina source). The middle course, the longest above-ground section of the Trebišnjica, drains 2,225 km².
regulation
Although the Trebišnjica flows in a geologically unstable karst area and comparatively irregularly, it has a great hydroelectric potential, which was harnessed by various regulatory measures, which were among the most extensive of their kind in Yugoslavia at that time .
- In 1965 the river at Gorica was dammed, creating a reserve reservoir for the future Trebinje hydropower plant . The water from this lake is led through two 16 km long tunnels to the Croatian town of Plat on the Adriatic coast near Cavtat , where it powers the Dubrovnik hydroelectric power station .
- 1967 The main dam for the Trebinje hydropower plant was built near Grnčarevo . The Bilećko jezero ( Bileća Lake or Miruša Lake ) was created with an area of 33 km², a maximum water depth of 104 m, and a volume of 1.3 billion m³. The lake level is 400 m above sea level. The old Arslanagić Bridge was dismantled and rebuilt in Trebinje. Together, the two hydroelectric plants in Dubrovnik and Trebinje have an output of 422 MW and produce up to 2.19 billion kWh of electricity annually.
- In 1979 the Čapljina hydropower plant was completed, which is supplied via an 8 km long tunnel and two reservoirs (with a volume of 12.5 million m³). The power plant has an output of 430 MW (2 × 215 MW) and can produce up to 619 million kWh annually.
- 1979 In order to reduce seepage in the area of Popovo polje, the river was channeled to a length of 67 km.
- In 2006 another tunnel of 15.6 km in length was completed, which leads part of the water from the Fatničko polje directly into the Bileća Lake.
swell
- ^ Dušan Dukić: Jugoslavija - Vode. In. J. Sirotković (ed.). Enciklopedija Jugoslavije. Second edition, vol. 6, Jap-Kat, Jugoslavenski leksikonigrafski zavod, Zagreb 1991. p. 191.
- ^ Petar Milanović: Dinaride Poljes. In: John Gunn (Ed.): Encyclopedia of Caves and Karst science. Fitzroy Dearborn, New York, 2004. ISBN 1-57958-399-7 , pp. 291-293.
- ^ Petar Milanović: Dinaride Poljes. P. 292
- Mala Prosvetina Enciklopedija , 3rd edition (1985); Prosveta; ISBN 86-07-00001-2
- Jovan Đ. Marković (1990): Enciklopedijski geografski leksikon Jugoslavije ; Svjetlost-Sarajevo; ISBN 86-01-02651-6
Web links
- Hydroelectric power plants on the Trebišnjica
- Study on the effects of the Fatničko polje tunnel (PDF file; 3.65 MB)
Coordinates: 42 ° 42 ′ 45 ″ N , 18 ° 20 ′ 51 ″ E