This project aims at the identification of a methodological approach for the analysis of medium-small basins prone to flash floods, this document is the conclusive study of the main territorial aspects of Civiglia basin, which represents a case study in order to put in practice the theoretic guidelines emerged in the development of project Premo. The study of the Civiglia basin represents both a practical application of the indications emerged in the evolution of the project and the verification and refining, with a direct evaluation of an actual case, of the theoretical analysis. This study is the prosecution of the preliminary analysis of Civiglia basin that was prepared in the first phase of project “Premo” in 1997-98. Information collected in that phase was integrated and examined in depth with analysis and field surveys that have consented to acquire a more complete information of the aspects directly or indirectly involved in the formation of flash alluvial events. In particular, the analysis of territorial aspects has foreseen the acquisition of technical information from Scientific Bodies and Public Offices in charge in the management and control of this river basin. On the basis of collected information, the study has aimed at the integration of the available data or the preparation of an ex-novo collection of the incomplete data. This procedure has permitted to prepare an up-dated and significant database of the territorial characteristics of this basin and to compare correlated information in order to identify the causes responsible for the formation of recurrent alluvial events that involve the lower urbanized area of the basin (Terrarossa area).