VISFRIM - The Italian case study: Lemene basin

The Lemene basin is located in northern Italy and covers an area of 1018 km2over the Veneto and Friuli Venezia Giulia (FVG) regions. It is delimited from the east by the Tagliamento river, from the west by the Meduna and Livenza rivers and from the south by the Caorle lagoon (Fig. 1).This transboundary basin is of high interest since, unfortunately, it has been frequently subject to flood events, the most recent one occurring in November 2019 (Fig. 2). 

Data collection phase

In order to setup the Lemene hydrological and hydraulic model, spatial and hydro-meteorological data have been collected. A brief description of such information is presented below:

Data harmonization and sharing

In order to facilitate data sharing among technical project partners and to support public consultation of flood-related information, the following steps were taken:

• processing and harmonizing all the previously collected spatial data according to a jointly structured geodatabase;
• development of a WebGIS platform through the open-source software Lizmap, a
• imed for online consultation of flood-related data and simultaneous processing by all the involved project partners (Fig. 3).

Hydraulic model

The hydrographic network from the Hydrogeological Structure Plan (PAI) for the Lemene catchment was considered as a reference for the development of a new hydraulic model, including, however, more recently acquired topographical data. In detail, in order to facilitate the import of raw geometrical data into the hydraulic model, different codes were developed, allowing for a more fluent and speedy inputting process. 

The 1D modelling of the entire PAI hydrographic network was completed (Fig. 4), as well as the 2D modelling of potentially flooded areas.

Future steps

In the upcoming months, the following activities are programmed:

• modelling analysis of low, medium and high probability flood scenarios;
• implementation of new river topographical surveys, whose spatial location is set on the basis of preliminary model results;
• update of the hydraulic model, inputting the new river sections’ data from planned topographical surveys.