Phreatimetric campaigns of the major valleys in Trentino

These are measurement campaigns aimed at knowing the depth and slope of the water table (also known as the phreatic surface). Measurements are made in wells and piezometers available in the area, and are concentrated over a few days and away from significant rainfall. At each point, the depth of the water table is measured. Several surface water levels (lakes and streams) are also taken on the same days. Each measurement point is located with a precision GPS, which also measures its altitude.

At the end of the campaign activity, a cloud of points characterised by a pair of coordinates (X,Y) and a Z, which expresses the elevation (in metres above sea level) of the water table at that time, is then obtained in GIS. The point data are then interpolated to obtain a spatial distribution, i.e. a surface representing the upper limit of the water table at that time. This surface is represented, similarly to what is done in topographical maps with the terrain, with curves of equal height, known as isophreatic curves.

Measuring campaigns are preferably carried out in the spring (in which the aquifer is most grazed, soft), and late summer (presumably lean), in order to get an idea of the maximum fluctuation of the water table.

Each measurement campaign thus provides a "snapshot" image of the surface area that delimits the upper part of the water table: this is conditioned by the climatic situation at that time, such as a dry season, or a particularly rainy one, or a more or less abundant thaw, but also by the extent and distribution of the withdrawals that take water from the water body.

Having several phreatimetric campaigns a few years apart makes it possible to obtain indications on theevolution of the water body over time: this evolution can be considered an indicator of the quantitative health of the aquifer and also of the sustainability of its exploitation.

Phreatimetric campaigns carried out in the Trentino valleys

* Campaigns carried out by the Geoalp study on behalf of the Geological Service of the P.A.T.

The isophreatic maps can be consulted via the following Webgis: