Long Term Discharge Analysis to Improve Knowledge About the Behavior of Karst Spring Under Climate Change—Praondè Spring, Civate (Lecco).

Climate change can significantly impact on water resource, in terms of quality and quantity. The combination of long dry summers with the change in the trend of precipitation (characterized by few but very intense events) is expected to influence the storage of water that could intensely decrease with important consequences on potable water in mountain area. Also, quality of water may change: water turbidity and water pollutant can increase. The aim of this work is to better understand the behavior of a karst spring (Praondè) located in the province of Lecco, in the town of Civate. The purpose is to identify possible models of spring behavior for a better management of water resource. In the beginning, precipitation, and temperature data, extrapolated from ARPA Lombardia, were analyzed to identify a specific climate trend in this area. Then, thanks to the collaboration with Lario Reti Holding S.p.A, discharge data of the spring were analyzed. Since November 2023 discharge data were paired with electro conductivity and temperature of the spring, thanks to the installation of a multiparameter probe. Since January 2024, an automatic sampler has been installed to collect a sample of water every day (24 days) to obtain a continuous isotopic series of oxygen and deuterium. To describe the behavior of the spring, several parameters were detected. These parameters provide us information on how aquifer in being drained and the level of vulnerability of the spring. The most important parameter detected is the depletion coefficient α (E. , Essais d’hydraulique souterraine et fuviale, vol. 1, Paris). The α analysis highlighted two different magnitudes, suggesting two different velocities of drainage. The data available highlighted that 2022 was the most drought year since 2015. The hope is that this work will help in the future for better water management to make up for the increasingly frequent drought periods that affect several areas of the world.