Silting estimation of the Farneto del Principe (Calabria, South Italy) artificial reservoir by means of the EPM model

In the present paper, the average annual silting of the Farneto del Principe artificial reservoir was estimated through the potential erosion model (EPM) in a GIS environment over a time range from 1991 to 2008. Four calculations were performed, the first by giving a value of the geo-lithological soil erodibility factor based on the table proposed in literature and three others by using different calibration methods (geomechanical, petrographic and granulometric). For each calculation, the net sediment volume arriving at the closing session was calculated. The net sediment volume values obtained have been compared with the average value of the siltation measured using the echo-sounder survey. It was noted that last three calculations show an overestimation of the silting of values of 45% for geomechanical calibration, 4% for petrographic calibration and 3% for granulometric calibration. Probable causes for this overestimation could be: i) the presence of the Esaro artificial lake at the closure section of the Farneto basin; ii) the fact that the EPM model incorporates in the net sediment volume value estimated part of the sediment trapped by infrastructures (bridges, waterfalls, etc.) along the river as no corrections are made for these during the appropriate calculation procedure. Although there are several overestimates, the results of the study show how the petrographic and granulometric calibrations proved to be better as they are closer to the real value of the silting.