GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 3.2 GNGTS 2024 Monitoring of the saline wedge in the Po di Goro river. P. Boldrin 1 , E. Ferrari 1 , F. Droghet 1 , A. Bondesan 2 , E. Rizzo 1 1 University of Ferrara (Dipartmento di Fisica e Scienze della Terra, Ferrara, Italy ) 2 Consorzio di Bonifca di Ferrara (Italy ) Keywords: salt wedge intrusion, EM, climate change, tdes Seawater intrusion in coastal aquifers is a worldwide problem caused, among other factors, by aquifer overexploitaton related to human actvites, such as irrigaton and drinking water supply, and the reducton in natural groundwater recharge due to climate change [1]. In order to prevent or limit the degradaton of both surface water and groundwater quality due to saltwater contaminaton, research studies have been conducted to gain a comprehensive understanding of the issue, identfy fundamental parameters, and assess possible correctve measures. The territory of the Po Delta is characterized by minimal slopes and it is largely situated below sea level. The elevaton profle of the territory signifcantly infuences land management. The morphological characteristcs of the Po Delta make the largest Italian wetland partcularly unstable and very fragile when subjected to human pressure. Only the applicaton of careful policies concerning coastal defence, food mitgaton, anthropogenic subsidence reducton and salt wedge intrusion control will allow reducton of the present or predicted negatve efects [2]. In order to detect the salinity of the water river, a probe system that measure the water conductvity (EC) is necessary. Typical monitoring system for EC data involves moving boat acquisitons, which depict a low resoluton of the salt wedge detecton. Moreover, long rivers are not suitable for point acquisiton approach as they require long acquisiton tmes. To overcome these limitatons, geophysical methods could appear as a good alternatve for fast mapping and detailed resoluton. Taking in account these aspects, a monitoring research actvity was applied along the Po di Goro River by geophysical method. In detail, a FDEM system was used to carry out the in-phase and out-phase components, in order to obtain the ECa distributon along the river. The geophysical monitoring began in summer 2022 [3], during the last salt wedge crisis along the Po River, and contnued this summer. The frst results of the Summer 2022 data set highlighted the saline wedge intrusion, on the contrary the Summer 2023 data set showed that saline intrusion was absent in the same investgated area. Anyway, the acquired data during last summer permited to observe the infuence of the tde on the advance and retreat of the salt wedge along the river (Fig.1). The results highlight the signifcant potental of the proposed geophysical