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Prevention of hydrogeological risk: long-term objectives for the defence against hydrogeological instability

Climate change poses challenges that require innovative measures to prevent and mitigate hydrogeological risk. Global warming affects the intensification of the hydrogeological cycle, leading to an increase in evaporation and precipitation. Such phenomena, in particular meteorological and environmental conditions, can affect the stability of slopes and river courses, affecting the safety of anthropic activity.
Soil defence action for the mitigation of hydrogeological risk (in the scenario of changing hazardous conditions due to climate change) pursues the following objectives:

• Maintenance and improvement of flood embankments
• Securing roads against hydrogeological instability
• Safety of inhabited centres from risks posed by hydrogeological instability.

The planning and programming of synergistic soil defence interventions with the organisation of the next edition of the Olympic and Paralympic Winter Games in Milano Cortina 2026 aims to intervene on the phenomena of hydrogeological instability that determine risk conditions in the territory involved in the event.

Prevention of hydrogeological risk: strategies in place to defend against hydrogeological instability

The planned interventions, with actions to ensure safety from hydrogeological instability, have involved two waterways in particular: the rivers Boite and Bigontina, which cross the territory involved in the event.
On the Boite River, "Extraordinary maintenance and adaptation of the hydraulic works on the Boite River in the section between the towns of Sopiazes and Polveriera in the municipality of Cortina d'Ampezzo (BL)" has been planned.
The measure refers to mitigation of the propagation effects of flooding by the Boite River, which induce both erosive and depositional phenomena in the section in question with consequent erosion of the banks, damage to the hydraulic defence structures present, introduced over 90 years ago, and possible flooding.
For economic-financial planning reasons, the project has been divided into several sections, two of which have already been carried out with OCDPC 558/2018 funds. A third section is in progress with funding requested as part of the national plan of interventions for the mitigation of hydrogeological risk of the MITE for the year 2022, to a total amount of 3,476,503.71 euros.

Subsequently, during the adjustment of the 2025-2027 regional budget, approved by Regional Law no. 16 of 4 August 2025, resources were made available that will allow for planning and starting by the end of the year the project for “Extraordinary maintenance and restoration of hydraulic defence works near the locality Polveriera on the Boite stream” for a total amount of € 700,000.00. For completing the intervention, it will be necessary to disburse funds for a fourth section, at a cost estimated at approximately € 4,000,000.00. Also on the Boite stream, on the right bank, following the flood event of August 2018, works financed with OCDPC 558/2018 funds were carried out for a total of € 1,500,000, which affected the Gatto brook in the area between the first section of the plants upstream of the regional road for Passo Falzarego and the confluence with Ru Torgo, with complementary road safety works.                                                                                                 

For completion of the intervention, it will be necessary to finance a fourth phase, with expenditure estimated at approximately 4,000,000.00 euros.

Also on the right bank of the Boite River, following the flooding of August 2018, works financed with OCDPC 558/2018 funds were carried out totalling €1,500,000. These works involved the Gatto brook in the area between the cable car station before the regional road for the Falzarego Pass and the confluence with the Ru Torgo, with complementary road safety works.

On the Bigontina River, after the violent debris flow event of 5 August 2017, a series of interventions were planned in collaboration with the Department of Land, Environment, Agriculture and Forestry (TESAF) of the University of Padua, for the safety of housing and road infrastructure throughout the entire basin. These included the mitigation of sediment transport, mass transfer by laminar flow and the adaptation of canalisation for the crossing of all inhabited areas (including the centre of Cortina) up to the confluence of the Boite, the adjustments and embankment maintenance. Thus, a series of organic interventions to reduce hydraulic risk were planned, divided by priority classes, according to geomorphic criteria with low environmental and landscape impact, for a total amount exceeding 8 million euro.

Once the “Drainage systems of the riverbed of the Bigontina stream and the minor right-bank tributary rivers” in the Municipality of Cortina D’Ampezzo (BL) has been completed, in order to complete the interventions on the Bigontina stream it would be necessary to complete maintenance and embankment works of the canal system located downstream of the Corso Italia bridge, at an estimated cost of at least € 3,000,000.00. 

Prevention of hydrogeological risk: additional funding to be found for defence against hydrogeological instability