What river morphology after restoration? The methodology VALURI

This paper proposes a tool which river managers may need to ascertain whether the key idea of River Restoration is valid, i.e. that rivers in more natural status are desirable not only for pure environmental reasons, but also to combat flood and geomorphic risk. The point addressed is how to predict the morphology and geometry that a river will assume after the application of a River Restoration project which foresees significant changes in the system of defence and exploitation works as well as morphological adjustments (e.g. reconnection of an incised main channel with the surrounding ex-floodplain). To this aim we developed a semi-quantitative methodology that integrates several differing criteria: from historical analysis of geomorphic evolution, expert-based mechanistic reasoning, checking with empirical qualitative formulas and analytical support from fluvial geomorphology and classic hydraulics. The development of the methodology has taken place on a case study along the 80 km of Chiese River, downstream of Idro lake, in northern Italy. Although the product to be considered is just a pilot one, we see it as a promising tool, which also opens several challenging questions suited for further fascinating research work.