RIVER MANAGEMENT: RIVER RESTORATION AND FLOOD HAZARD Nicola Surian Department of Geosciences, University of Padova Masaryk University Brno, 24 September 2019 Introduction Most of the rivers (at least in Europe) are managed River management…a geomorphic perspective Content and aims of this lecture 1. River management: key concepts 2. River management in Europe 3. The role of fluvial geomorphology in river management River management: key concepts Managing the river…and its catchment A complex system: natural processes and human activities What is river management (e.g. small and large scale interventions)? Who manages the river? THE FLUVIAL SYSTEM Temporal scales (from Newson and Sear, 1993) A complex system: natural processes and human activities Main uses of rivers: Agriculture Navigation Production of energy Drinking water Recreation activities …and flood protection Channelization Dams Bank protection Sediment mining Who manages the river or play a role in river management? River management in Europe Water Framework Directive (2000/60/CE): to improve ecological quality of rivers Flood Directive (2007/60/CE): mitigation of flood risk «Integrated river management» Water Framework Directive (WFD)? Drivers Pressures State Impacts Reponses (Measures) E’ DATO DALLA COMBINAZIONE DELLO STATO DI: Ecological condition of rivers 3. Elementi idromorfologici: regime idrologico, continuità fluviale, condizioni morfologiche 1.Elementi biologici 2. Elementi chimico-fisici (generali, inquinanti specifici) Elevato Buono Moderato Scarso Cattivo Nessuna o minime Moderate Rilevanti Severe PRESSIONI STATO Ecological condition of rivers Leggere The role of fluvial geomorphology in river management An historical perspective: traditional approach (manly an engineering approach) and modern approach (including also geomorphology and ecology) From «control of nature» to «work with nature» Key physical processes that should be taken into account: Fluvial processes Appropriate spatial and temporal scales Bank erosion Classe A: frequenti sponde in arretramento, soprattutto sul lato esterno delle curve (frecce rosse nella foto a sinistra). A Bank erosion Classe C: completa assenza o presenza molto trascurabile (erosioni molto localizzate) di sponde in erosione per presenza di interventi di protezione e/o dinamica dell’alveo assente. C Erodible corridor Classe A: nonostante il centro abitato e la strada, è presente una fascia potenzialmente erodibile continua e sufficientemente ampia. Classe B: la fascia erodibile presenta media continuità (33÷66%) e qualunque ampiezza (seconda figura da sinistra), oppure è continua (>66%) ma non sufficientemente ampia (larghezza media