Groundwater Flow Modeling for the Sustainable Exploitation of the Monte Castello Aquifer

Ravedis reservoir is located in the Carnic Prealps, within the municipality of Montereale Valcellina (Friuli Venezia Giulia, North Eastern Italy). It is fed by Cellina stream, and is situated just before the outlet of Cellina Valley in the Venetian-Friulian Plain. The reservoir was designed to mitigate flood events and to store water for hydroelectric power generation and for irrigation purposes. For this reason, the lake level is raised in summer to higher levels than in the winter or wet months. This study focuses on Monte Castello, a thin hilly system that separates the reservoir from the plain. It hosts an aquifer characterized by the presence of variously fractured dolomitic limestone. The reservoir’s creation resulted in a change in groundwater supply regime downstream of it. The presence of the lake guarantees, especially in the dry summer months, a constant source of recharge for the Monte Castello aquifer. This fact prompts evaluation of the Monte Castello aquifer's potential for use as an alternative to plain groundwater resources, which are more susceptible to overexploitation and climate change. An extensive work of bibliographic research and analysis of piezometric data by means also of geostatistical techniques was carried out in order to characterize the study area from a hydrogeological point of view. This study is aimed at developing a groundwater flow model of the study area with Modflow. The three main goals of the research are: - To obtain, through inverse modeling, a reliable estimate of the distribution of the hydraulic conductivity parameter; - To estimate the amount of water that leaks underground from Ravedis reservoir or, in other words, its losses; - To simulate the effects of drilling a pumping well to supply water to Montereale Valcellina and surrounding villages. The sustainable management of water bodies like Monte Castello’s one, small in size but with a high potential, could represent one of the ways forward to a more resilient response to the growing demand for high-quality water resources.