Flood-induced ground effects and flood-water dynamics for hydro-geomorphic hazard assessment: Orba River (Alessandria, Italy)

GEOCORSI E-learning

Andrea Mandarino, Fabio Luino & Francesco Faccini (2021):
Flood-induced ground effects and flood-water dynamics for hydro-geomorphic hazard assessment: the 21–22 October 2019 extreme flood along the lower Orba River (Alessandria, NW Italy). 
Journal of Maps
To link to this article: https://doi.org/10.1080/17445647.2020.1866702

Abstract
The knowledge of flood-induced ground effects and flood-water dynamics is a crucial issue for hydro-geomorphic hazards assessment and mapping, and thus for river management and land use planning. This paper and the related 1:15,000 map illustrate the lower Orba River (NW Italy) and its adjacent floodplain geomorphic response to the 21–22 October 2019 extreme flood. This was estimated to be a 500-years flood and caused severe damage to cultivated fields, structures, and infrastructures. The research is based on extensive post-flood field surveys, ante- and post-flood GNSS surveys, and aerial photographs interpretation. Intense in-channel sediment mobilization, bank retreats, and channelization structures collapses were surveyed. Furthermore, alluvial gullies, overbank deposits, crevasse splays, and surficial-erosion evidences were mapped over the floodplain, along with the flooded area (17.65 km2) and the flood-water features. A specific legend developed for flood-related and anthropogenic elements mapping in a typical lowland agricultural landscape with regulated rivers is proposed.

KEYWORDS
Floods, geomorphic effectiveness, geomorphological mapping, alluvial gully, Orba River, north-western Italy

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.​
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