Sediment Transfer through the Fluvial System (Proceedings of a symposium held in Moscow, August 2004). IAHS Publ. 288, 2004 308 Sediment transport and morphodynamics of the Tanaro River, northwestern Italy ANNUNZIATO SIVIGLIA 1 , BIANCA FEDERICI 1 , IGNAZIO BECCHI 2 & MASSIMO RINALDI 2 1 Dipartimento di Ingegneria Ambientale, Università di Genova, via Montallegro 1, I-16145 Genova, Italy nunzio@diam.unige.it 2 Dipartimento di Ingegneria Civile, Università di Firenze, via S. Marta 2, I-50139 Firenze, Italy Abstract This paper describes a study to determine sediment transport processes and morphodynamics of the Tanaro River in northwestern Italy to support river manage- ment strategies. An integrated hydraulic-geomorphic approach was used to: (a) assess geology, land use and climate controls affecting sediment yield at the catchment scale; (b) evaluate changes in channel morphology and sediment transport processes; (c) model river channel change. Numerical simulations were used to evaluate the transient solution for flow and bed profile due to the propagation of the flood wave. It is concluded that Alessandria town is the most critical reach from the flooding point of view and so different design solutions were tested in order to verify whether geometric alteration of the river bed would allow for an increase in flood capacity. Key words bed equilibrium configuration; channel changes; morphodynamic; sediment transport; Tanaro River, Italy INTRODUCTION River management programmes in Italy rarely address sediment transport processes in the design of flood control structures (Autorità di Bacino del Fiume Po, 1997; Autorità di Bacino del Fiume Arno, 2000). More recently, there has been an increasing awareness of regional sediment issues and channel morphodynamics as an integral part of river manage- ment. Consequently, there is a need to develop or further refine methodological approaches that include an assessment of sediment transport processes and morphodynamics to ensure their application to widespread river management practice. A multidisciplinary study is required to quantify catchment and reach-scale processes, forms and causes of instability as a basis for quantitative hydraulic modelling and analyses (Environment Agency, 1998; Thorne, 1998). A large flood event, with an estimated return period of about 100 years, occurred along the Tanaro River in northwestern Italy during November 1994. During the event, hundreds of landslides occurred in the drainage basin and sediment transfer to and by the river resulted in damage to several towns. This event emphasizes the need for developing better flood control strategies and to take into account sediment transport processes and morphodynamic aspects of river management. The objective of this paper is to examine morphodynamic and sediment transport processes in the Tanaro River to provide appropriate information for river management. Data on channel morphology and sediment transport are used to develop a numerical model to calculate the equilibrium configuration and possible effects of bed changes on flood capacity.