| Popis: |
Two of the largest sinking rivers in Europe, the Lika and Gacka rivers, are located in the region called Lika in Croatia. Studied region is the central part of the Dinaric karst and the divide between Black Sea and Adriatic watersheds is running through it. Both of the rivers belong to the Adriatic watershed. The water, swallowed in the karst underground on the numerous swallow holes, can be traced to the submarine karst springs along the Adriatic Sea coast. Lika and Gacka are the rivers of a great interest for the hydrologists because of their close vicinity, yet extremely different hydrologic regimes. The Lika River has torrential water regime and its tributaries with characteristics of ephemeral streams, generate a ratio between its minimum, mean and maximum discharges: 1:130:3800. On the other side, that ratio by the River Gacka, a perennial river, is: 1:4:27, where its minimum discharge values are no less than 2, 2 m3/s. The water losses by the both rivers along their open watercourses are significant, especially in the case of the Lika River. In the summer months, the River Lika can have no discharge at all. According to topography of the two chatchment areas and its hydrogeological characteristics, an assumption can be made, that a great part of water losses of River Lika reappears in the springs of River Gacka. Physical evidence in the form of the karst connection through the conduits in the underground between two rivers hasn't been discovered yet, but many of geologists and hydrologists are working on it. The origin of the water in the springs of the Gacka River can be partially assigned to the topographic catchment, but the most quantities of water are feeding the springs by the karst underground flow. |
