The karst complex of "Grotte di Frasassi-Grotta Grande del Vento" is located in the gorge cut by the River Sentino in the anticline of Mt. Valmontagnana, about 50 km from the town of Ancona (central Italy). In order to manage the caves in a rational way, and to get new information about the karstic processes at the cave "Grotta Grande del Vento", a computerized monitoring system was installed for temperature, humidity, rain, percolation and air velocity, inside and outside the cave complex. The first data collected suggest the following preliminary results: (a) Normally the flow of groundwater is towards the Sentino River. During floods this flow is reversed. The effect of the waters mixing can increase karstic dissolution. This hypothesis seems to be confirmed by the greater dimensions of the cavities close to the Sentino River, (b) As expected there is a close correlation between air flow through the cave and the temperature difference inside and outside the cave. However the data seem to show that in some zones of the caves the air flow is mainly controlled by the processes of condensation-evaporation, (c) The condensation phenomena probably play an important role in the karstic evolution of the system, (d) An initial estimation of the groundwater draining into the Sentino River along the Frasassi Gorge has been made (about 50 1/s); according to the Maillet equation the depletion constant of the river is 2.8 X 10"2 day"1, that of the aquifer is around 8.4 x 10"2 day"1.
First results of the Monitoring System of the karstic complex of " Grotte di Frasassi-Grotta Grande del Vento", (Central Apennines, Italy)
DRAGONI, Valter Ulderico;
1990
Abstract
The karst complex of "Grotte di Frasassi-Grotta Grande del Vento" is located in the gorge cut by the River Sentino in the anticline of Mt. Valmontagnana, about 50 km from the town of Ancona (central Italy). In order to manage the caves in a rational way, and to get new information about the karstic processes at the cave "Grotta Grande del Vento", a computerized monitoring system was installed for temperature, humidity, rain, percolation and air velocity, inside and outside the cave complex. The first data collected suggest the following preliminary results: (a) Normally the flow of groundwater is towards the Sentino River. During floods this flow is reversed. The effect of the waters mixing can increase karstic dissolution. This hypothesis seems to be confirmed by the greater dimensions of the cavities close to the Sentino River, (b) As expected there is a close correlation between air flow through the cave and the temperature difference inside and outside the cave. However the data seem to show that in some zones of the caves the air flow is mainly controlled by the processes of condensation-evaporation, (c) The condensation phenomena probably play an important role in the karstic evolution of the system, (d) An initial estimation of the groundwater draining into the Sentino River along the Frasassi Gorge has been made (about 50 1/s); according to the Maillet equation the depletion constant of the river is 2.8 X 10"2 day"1, that of the aquifer is around 8.4 x 10"2 day"1.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
