Specifics of hydrological functioning in two neighbouring karst springs: a case study from the Dinaric karst
摘要
This study presents the hydrological analysis performed on two adjacent karst springs, Rumin Veliki and Rumin Mali, located 640 m apart in a straight line. Rumin Veliki is a perennial spring, whereas Rumin Mali is intermittent and situated 19.2 m higher in elevation. Both springs lie within the Cetina River basin in Croatia, with their catchment areas predominantly extending into Bosnia and Herzegovina. The commissioning of the Orlovac Hydropower Plant in 1973 significantly altered the hydrological regime of both springs. In the period up to and including 1972, the characteristic annual flows (minimum, mean, and maximum) under natural, undisturbed conditions were significantly higher than those observed from 1973 onward. The average annual discharge of Rumin Veliki under natural conditions was 18.6 m3/s, which has decreased by 11.7 m3/s to 6.9 m3/s in recent years. Similarly, the average annual discharge of Rumin Mali declined from 2.74 m3/s in its natural state by 1.03 m3/s to 1.71 m3/s in the present period. This reduction in characteristic flows is attributed to water diversion through a system of canals and barriers constructed in Livanjsko Polje, directing water to the Lipa and Buško Blato reservoirs. The study further investigates whether these two spring are fed by the same aquifer. While the findings strongly suggest this possibility, additional measurements are recommended to reach a definitive and reliable conclusion.