The Gran Sasso is a calcareous-karst aquifer of about 1000 km2 of total extension, one of the most representative karst aquifers of the central-southern Apennines. The permeability due to fractures and the karstification of the Gran Sasso calcareous complex are influenced by the stratigraphic and structural elements. They often act as an obstacle to groundwater flow determining different hydrogeological subbasins and influencing the flowpaths. Within the framework of the European project KARMA (karma-project.org), a tracer test was carried out in April 2022 in the recharge area of Tavo springs (Vitella d’Oro and Mortaio d’Angri springs). One injection point (Rigopiano ditch) and two selected monitoring points (i.e., Vitella d’Oro spring and Tavo River), located at the north-eastern boundary are considered. We used previous turbidity events which occurred at the Vitella d'Oro spring as basis for planning the tests. Uranine and Sodium Naphthionate were used as tracers, as they are considered to be toxicologically safe for humans and the environment, a necessary condition for the application in a National Park such as the Gran Sasso Mountain. The monitoring has been performed using two continuously measuring field fluorometers, coupled with discrete water sampling, and charcoal bags at different locations. Both continuous data and discrete ones highlighted the arrival of the Uranine dye 9 h 45 min and 11 h after the injection, at Tavo River and at Vitella d’Oro spring, respectively. The results highlighted that catchment areas are different although the two springs belong to the same regional Gran Sasso aquifer. Besides, by analysing the charcoal bags, we inferred the superimposition of two local flowpaths, a shallow and fast one, and a deeper and slower one, both feeding the Vitella d'Oro spring. The results obtained show how the springs are particularly sensitive to both basin-scale variations and local conditions, placing them as vulnerable to discharge reduction/exhaustion in a potential climate change scenario.
New Insights on Groundwater Flow of the Tavo Tapped Karst Springs (Gran Sasso Aquifer, Central Apennines) Using Tracer Tests
Sergio Rusi
2023-01-01
Abstract
The Gran Sasso is a calcareous-karst aquifer of about 1000 km2 of total extension, one of the most representative karst aquifers of the central-southern Apennines. The permeability due to fractures and the karstification of the Gran Sasso calcareous complex are influenced by the stratigraphic and structural elements. They often act as an obstacle to groundwater flow determining different hydrogeological subbasins and influencing the flowpaths. Within the framework of the European project KARMA (karma-project.org), a tracer test was carried out in April 2022 in the recharge area of Tavo springs (Vitella d’Oro and Mortaio d’Angri springs). One injection point (Rigopiano ditch) and two selected monitoring points (i.e., Vitella d’Oro spring and Tavo River), located at the north-eastern boundary are considered. We used previous turbidity events which occurred at the Vitella d'Oro spring as basis for planning the tests. Uranine and Sodium Naphthionate were used as tracers, as they are considered to be toxicologically safe for humans and the environment, a necessary condition for the application in a National Park such as the Gran Sasso Mountain. The monitoring has been performed using two continuously measuring field fluorometers, coupled with discrete water sampling, and charcoal bags at different locations. Both continuous data and discrete ones highlighted the arrival of the Uranine dye 9 h 45 min and 11 h after the injection, at Tavo River and at Vitella d’Oro spring, respectively. The results highlighted that catchment areas are different although the two springs belong to the same regional Gran Sasso aquifer. Besides, by analysing the charcoal bags, we inferred the superimposition of two local flowpaths, a shallow and fast one, and a deeper and slower one, both feeding the Vitella d'Oro spring. The results obtained show how the springs are particularly sensitive to both basin-scale variations and local conditions, placing them as vulnerable to discharge reduction/exhaustion in a potential climate change scenario.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
