Hydrogeothermal characteristics of groundwater from Ribarska Banja spa, central Serbia

Veselin Dragisic,Vladimir Zivanovic,Tanja Petrovic-Pantic

doi:10.2298/gabp1576061d

Abstract

Ribarska Banja spa is one of the most popular balneotherapy and recreation centers in Serbia. It features several thermal groundwater sources whose temperatures range from 26 to 54?C. The mineral content of these waters is low and their composition is of the SO4-Na or HCO3-Na type. Thermal water exploration has been conducted in the general area for many years, to assess the hydrogeothermal potential in order to extract larger amounts of thermal water for multiple uses. The hydrogeothermal system of Ribarska Banja spa was defined based on a synthesis of the results of comprehensive structural geology, geophysical, hydrogeological, hydrochemical and geothermal research. The primary groundwater reservoir of the hydrogeothermal system is comprised of tectonic zones (systems of faults and fractures) within Cretaceous-Paleogene metamorphosed and non-metamorphosed rocks. The overlying hydrogeological and temperature barrier is made up of a series of low metamorphosed rocks (chlorite, chlorite-sericite schists, gabbros, etc.), highly metamorphosed rocks (gneisses) and Neogene clay and sand sediments. The system is recharged by infiltration of atmospheric precipitation and surface water at the highest elevations of Mt. Jastrebac. Investigations have also shown that the system?s heat source is younger granitoide intrusion spreading northwest of Ribarska Banja spa. Based on the quartz geothermometers, expected reservoir temperatures are in the range of 85-97?C that can be expected at a depth of 1.87 km. Total energy usage at Ribarska Banja spa is 31 TJ/y with thermal capacity of 1.65 MWt and utilization factor of 0.58. Geothermal gradient is 0,051?C/m, while heat flow density is 163.5 mW/m2.

Highlights

Ribarska Banja spa is located in central Serbia, on the northeastern slopes of Mt
The thermal water samples at Ribarska Banja spa were found to be alkaline with a low EC (Table 3)
The hydrogeothermal system of Ribarska Banja spa was defined on the basis of structural geology, geophysical, geothermal, hydrogeological, hydrodynamic and hydrochemical research conducted in the narrow and extended zones of thermal water discharges

Summary

Introduction

Ribarska Banja spa is located in central Serbia, on the northeastern slopes of Mt. Jastrebac.Thermal water wells, featuring water temperatures in the range from 26 to 54 °C, as well as thermal spa facilities, are situated in the Ribarska River valley, some 3 km from the village of Ribare. Intensive research of thermal waters starting in the late seventies (MILOVANOVIĆ 1978; MILOVANOVIĆ 1980; MILOVANOVIĆ 1992; MILOJEVIĆ 2004; ŠPADIJER et al 2005; ŽIVANOVIĆ & ATANACKOVIĆ 2013). Drilling yielded considerable amounts of water from metamorphic rocks, characterized by increased temperatures suggesting the existence of a complex hydrogeothermal system. It was originally assumed that the system was recharged at higher altitudes of Mt. Jastrebac and that its granitoid was the cause of the elevated temperature groundwater regime at Ribarska Banja spa (MILOVANOVIĆ 1980; MILOVANOVIĆ 1992). Recent research (ŠPADIJER et al 2005; ŽIVANOVIĆ & ATANACKOVIĆ 2013), like as stable isotope analyses and chemical tests of the water samples collected from wells allowed insight into the individual contributors to the formation of the hydrogeothermal system of Ribarska Banja spa, from the source of recharge to the point of discharge

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