KARST GROUNDWATER IN THE UPPER REACH OF ABDALKA RIVER (SIMFEROPOL, THE CRIMEAN PIEDMONT)
The paper is devoted to study the condition of karst waters flow in the upper reaches of the river Abdalka basin (Simferopol, Crimea). In the course of the studies performed, it was established that the key role in the formation of karst waters feeding the Verhny Kluch and Bely Kluch springs have precipitation, swallowing flow of the Abdalka river in Rakov ponor and anthropogenic groundwater formed on the garden and residential areas as a result of irrigation and leaks. These waters are distributed unevenly among the springs in the discharge area. Predominant portion of groundwater flow discharged through Bely Kluch spring providing its permanence, high flow rate and stable temperature. Verhny Kluch spring demonstrates frequent summer drying and relatively contrast in seasons temperatures. There is a relatively high synchronization of the response of springs waters to events (precipitation, the appearance and disappearance of the swallowing flow, etc.) occurring in the recharge area in winter-spring (high filling system) and approximately a month delay in summer-autumn period (low filling system). Taking into account the distance between the Rakov ponor and the Verhny Kluch springs, in the latter case it is possible to calculate the average velocity of karst waters movement (1.5 km / 30 days) 50 m / day. An analysis of the combined graphs of the distribution of temperature and flow characteristics of the spring waters within the year generalized for the entire observation period showed that there is a reliable statistical relationship between the flow rates and water temperatures in both springs. In each of the springs, when studying the relationship of flow-temperature within a year, two periods are distinguished with a direct and inverse dependence of the considered parameters. This indicates that the springs are recharged from a same karst groundwater system. The electrical conductivity and mineralization of the springs show no significant correlation. Intra-annual variations of their values in the case of the Verhny Kluch can be explained by controlling influence of temperature, but in the case of the Bely Kluch, it is almost impossible to explain them. To understand the causes of uncorrelated variability, additional studies are needed involving stable water isotopes method. Nevertheless, it can be stated that the formation of electrochemical parameters of waters occurs after the karst groundwater system is divided into independent channels recharging each springs.