Water temperature and electrical conductivity as an indicator of karst aquifer: the case of Jadro Spring (Croatia)

Abstract The variability of continuous hourly water temperature data and electrical conductivity measured at the Jadro karst spring was analysed for the period from January 1, 2011, to December 31, 2021. In this paper, the mean daily air temperature and daily precipitation data measured at the meteo...
Ausführliche Beschreibung

Abstract The variability of continuous hourly water temperature data and electrical conductivity measured at the Jadro karst spring was analysed for the period from January 1, 2011, to December 31, 2021. In this paper, the mean daily air temperature and daily precipitation data measured at the meteorological station Sinj, and the mean daily flow of the Jadro Spring, in the period 1995–2021 were also used. The analyses were performed on various time scales of year, month, and day. The aquifer that feds Jadro Spring has a very complex hydrogeological structure that is insufficiently explored. Jadro Spring has a limited capacity of maximum discharge. Its catchment area is not defined precisely. The relationship between water temperature and electrical conductivity is directly proportional while the relationship between water temperature and spring discharge is inversely proportional. As the flow of the spring increases, water temperature and electrical conductivity decrease. The narrow range of water temperatures and electrical conductivity indicates that the karst aquifer from which the spring is fed is not directly influenced by air temperatures and that flow does not occur through large karst conduits with a free water surface. The underground water level is located deep below the surface of the terrain, more than 100 m. Ausführliche Beschreibung