The 7 March 2015 flood event at the Asso Torrent basin (Apulia, Italy)

The 220km2 extended Asso Torrent basin (Apulia, Southern Italy) is crossed by natural and artificial channels flowing towards swallow holes and absorbing wells. The 7th March of 2015, the basin was struck by an unpredicted flood event. Rain intensity during the previous days was not exceptional, however damages to agriculture and dangers to vehicle traffic were experienced. In this respect, the analysis of the event may be useful to improve the alert system of the regional Protection Civil Agency. Despite of several urban and rural floods occurred in the last decades, new problems of water management raised after this event, because of the extensive hydraulic works previously made to reduce the hazard. The areas damaged by the event are placed at the lower branch of the basin (surrounding of karst swallow holes) and at the middle branch. From the analysis of precipitation of the CNR ISAC micrometeorological station it is apparent that the runoff generated by rains on 5th and 6th of March added to that of the previous days (not yet absorbed by the receptors), thus causing an overflow. The prediction of the flood events at the Asso Torrent basin needs two elements: a) a network of hydrometric stations and rain gauges; b) an efficient hydrologic model based on the actual geological features of the basin. In this note, indications are reported about these two elements in the context of a preliminary work, together with the analysis of the 2015 flooding.