Case study: Efficiency of slit-check dams in the mountain region of Versilia Basin

Slit-check dams are widely employed in mountain river control. However an analysis of their performance in the field is still lacking. In the present work a field verification to evaluate the interaction between solid discharge regime and four slit-check dams built in two subcatchments of the Versilia River in Tuscany, Italy is presented. The analysis is based on a relatively detailed field knowledge consisting of hydrological, topographical, and sedimentological data, together with a recent model proposed by Armanini and Larcher. Slit-check dam efficiency is analyzed in terms of deposit formation during major floods and its influence on long-term sediment transport regime. Results suggest that the design efficiency is affected by the high sediment trapping capacity associated with the relatively minor floods. A comparison between the deposit geometry predicted by the theory and the field measurements gathered during a systematic monitoring activity shows good agreement.