On January 31st, from 10:35 to 11:20, in Grandori Room (Building 4 – Piazza Leonardo da Vinci, 32 – Milan), a seminar titled “Flood hazard mapping: the HORA project” will be held by Prof. Günter Bloeschl (TU Wien, Institute of Hydraulic Engineering and Water Resources Management).

Following that, from 11:30 to 12:30, there will be a round table discussion with Prof. Günter Bloeschl, Prof. Renzo Rosso, and Prof. Giovanni Menduni, addressing the question: “Which design recommendations are suitable for flood hazard mitigation in urbanized territory under climate change meteorological forcing?”

The seminar is accessible online at the following link.

Abstract

Flood hazard mapping is currently in a transitional phase involving the use of data and methods that were traditionally the domain of local studies in a regional or nation-wide context. Challenges include the representation of local information such as hydrological particularities and small hydraulic structures, and computational and labour costs. This paper proposes a methodology of flood hazard mapping that merges the best of the two worlds (local and regional studies) based on experiences in Austria. The analysis steps include (a) quality control and correction of river network and catchment boundary data; (b) estimation of flood discharge peaks and volumes on the entire river network; (c) creation of a digital elevation model (DEM) that is consistent with all relevant flood information, including river bed geometry; (d) simulation of inundation patterns and velocities associated with a consistent flood return period along the entire river network. In each step, automatic methods are combined with manual interventions in order to maximise the efficiency and at the same time ensure estimation accuracy similar to that of local studies. The accuracy of the estimates is evaluated in each step. The study uses flood discharge records from 781 stations to estimate flood hazard patterns of a given return period at a resolution of 2 m over a total stream length of 38000 km. It is argued that a combined local-regional methodology will advance flood mapping, making it even more useful in nation-wide or global contexts.