In the Tagliamento Valley (NE Italy) are present several
situations related to sinkholes and subterranean voids
threatening the built-up environment above, as the Quinis
village. In particular many absorption points occurred in the
Enemonzo municipality. This last one committed to the
researchers of the Trieste Univ. and OGS institute a
multidisciplinary study in order to define and outline the
sinkholes phenomena and to individuate the triggering factors.
The historical analysis permitted firstly to identify the
phenomena evolution during the last century, the cases that took
to the demolishment of the existing buildings, among which
there was also the church, and the ones that today are still
causing instabilities. This allowed to realize a monitoring network
for the unstable infrastructures and a defined geophysical and
hydrogeological monitoring program. To better understand the
groundwater flow mechanisms and to try to define the intrinsic
vulnerability of the different areas a multidisciplinary approach
was adopted. A groundwater monitoring network consisting of
several multiparametric devices (electrical conductivity,
temperature and water level) was implemented. Water samples
were collected and geochemical analysis performed. Two wells
were equipped with assestimeters. The groundwater table has
huge variations between dry and rainy seasons and also between
two different precipitation events. Geological and
geomorphological surveys jointly with the stratigraphical data
and geophysical ones (seismic, ERT and GPR techniques)
permitted to deeply investigate the area and to reconstruct the
bedrock and the quaternary deposits above. Quinis village lies on
fluvio-glacial and alluvial deposits with an estimate thickness of 6
- 40 meters. The northern part of the study area, characterized
by the outcropping of evaporitic units (Upper Carnic), is widely
affected by caves, voids and dolines. The present study illustrates
the state of the art on the sinkhole knowledge in Enemonzo
municipality and shows how a broad spectrum investigation can
help in identifying safer areas for a more conscious future
territorial planning.
