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Dinamiche dei sedimenti sospesi nella Laguna di Venezia: effetti delle mareggiate e del sistema MOSe

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La Laguna di Venezia rappresenta un ecosistema unico e fragile, costantemente esposto a pressioni naturali e antropiche. Un recente studio, pubblicato nel Journal of Hydrology, approfondisce gli effetti delle mareggiate e delle operazioni del sistema MoSE sui flussi di sedimenti tra la laguna e l’Adriatico, con implicazioni rilevanti per la gestione e la sostenibilità dell’area.

Il sistema MoSE (Modulo Sperimentale Elettromeccanico) è stato concepito per proteggere Venezia dalle alte maree. Tuttavia, il suo impatto sui flussi idrici e di sedimenti è stato meno studiato fino ad oggi. Lo studio si è concentrato su due eventi significativi: una mareggiata nel novembre 2022 e una nel gennaio 2023. I dati raccolti provengono da una rete di osservazione integrata, che combina immagini satellitari e misurazioni in situ ai tre principali ingressi della laguna: Lido, Malamocco e Chioggia.

Principali risultati

  1. Flussi di sedimenti durante le mareggiate:
    • Durante l’evento del 2022, si è registrata una perdita netta di circa 13.880 tonnellate di sedimenti dalla laguna.
    • Nel 2023, la perdita totale è stata simile (14.850 tonnellate), ma con differenze regionali: l’importazione di sedimenti ha prevalso nel bacino settentrionale (Lido), mentre l’esportazione ha predominato nei bacini centrale e meridionale (Malamocco e Chioggia).
  2. Ruolo delle barriere mobili:
    • Le chiusure del MoSE riducono significativamente la perdita di sedimenti durante le mareggiate, ma impediscono anche l’ingresso di materiali sospesi provenienti dall’Adriatico, che sono fondamentali per il bilancio sedimentario della laguna.
  3. Effetti sul bilancio sedimentario:
    • La regolazione operata dal MoSE può avere effetti positivi a breve termine, limitando la perdita di sedimenti. Tuttavia, a lungo termine, potrebbe aggravare l’erosione di habitat chiave come le barene e i bassi fondali lagunari, già minacciati dall’innalzamento del livello del mare.

Implicazioni per la gestione

I risultati sottolineano l’importanza di un approccio adattivo nella gestione del sistema MoSE. L’implementazione di modelli di previsione e monitoraggio in tempo reale potrebbe ottimizzare l’uso delle barriere, bilanciando la protezione contro le alte maree e il mantenimento degli habitat lagunari.

In un contesto di cambiamenti climatici, con un innalzamento progressivo del livello del mare, il mantenimento della diversità geomorfologica e degli ecosistemi della laguna diventa una sfida cruciale. Lo studio suggerisce che interventi mirati e una gestione integrata possono offrire soluzioni replicabili per lagune e aree costiere in tutto il mondo.

Contributi scientifici e collaborazione

Questa ricerca, parte del programma Venezia2021 coordinato da CORILA, è stata realizzata con il contributo del Provveditorato per le Opere Pubbliche del Veneto, Trentino-Alto Adige e Friuli Venezia Giulia. I dati raccolti e analizzati provengono da un sistema di osservazione avanzato, sviluppato in collaborazione con enti di ricerca nazionali e internazionali.

Per approfondire i risultati e le metodologie adottate, è possibile consultare l’articolo completo su Journal of Hydrology (link all’articolo).

Listing Details

Titolo: Suspended sediment dynamics at the inlets of Venice Lagoon: Unraveling the effects of storm surges and mobile barrier operations
DOI: https://doi.org/10.1016/j.jhydrol.2024.132588
Autore: Gian Marco Scarpa
Rivista: Journal of Hydrology
Anno: 2025
Parole chiave: Sediment transportVenice LagoonFlood barriersMoSE projectIn-situ instrumental networkStorm surge
Citazione: Gian Marco Scarpa, Silvio Davison, Giorgia Manfè, Giuliano Lorenzetti, Luca Zaggia, Federica Braga, Suspended sediment dynamics at the inlets of Venice Lagoon: Unraveling the effects of storm surges and mobile barrier operations, Journal of Hydrology, Volume 651, 2025, 132588, ISSN 0022-1694, https://doi.org/10.1016/j.jhydrol.2024.132588. (https://www.sciencedirect.com/science/article/pii/S002216942401984X) Abstract: This study investigates the effects of flow regulation by the floodgate system (MoSE: Electromechanical Experimental Module) on sediment and water exchanges between the Venice Lagoon and the Adriatic Sea, during two significant storm surges in 2022 and 2023. An integrated observation system, which combines satellite-derived products and data from in-situ instrumental networks, was implemented at the three lagoon inlets (Lido, Malamocco and Chioggia). The high spatial and temporal resolution of continuous in-situ data allowed to characterize the complex interactions between sediment fluxes driven by tidal flow and the repeated and prolonged activations of the floodgates, considering the intense particle resuspension within the lagoon and along the coasts by wind waves. Our findings reveal a quite similar net sediment loss from the lagoon during each event (∼13,880 tons and ∼ 14,850 tons), but with distinct spatial and temporal patterns in the four inlet channels. During the 2022 event, sediment export during ebb tides exceeded import during floods, leading to a net loss at all inlets (Chioggia ∼ 4,720 tons, Malamocco ∼ 3,360 tons, Lido ∼ 5,800 tons). By contrast, in the 2023 event, sediment import dominated in the northern basin (Lido ∼ 5,900 tons), while export prevailed in the central and southern basins (Malamocco ∼ 6,570 tons, Chioggia ∼ 14,160 tons). As observable in satellite images, this input at north is related to fine particles resuspended under northeasterly wind along the adjacent coast and transported in the lagoon by flood tidal currents. The presence of jetties at the inlets interrupts the natural coastal drift at south inhibiting such inputs at central and southern basins. Besides being effective in preventing high waters in Venice, this study suggests that the regulation operated by the barriers can potentially determine positive or negative short-term feedbacks on the lagoon sedimentary budget, minimizing sediment losses from the lagoon or blocking the inputs from the nearby coast. In an operational context, near real-time information deriving from the tested methodology can support an effective management of the MoSE system, adaptable to the evolution of meteo-marine conditions. In the long term, adaptive strategies are essential to prevent alterations of the sediment fluxes and the consequent loss of habitat in shallow tidal environments that are already threatened by natural and anthropogenic pressures. Keywords: Sediment transport; Venice Lagoon; Flood barriers; MoSE project; In-situ instrumental network; Storm surge
Abstract: This study investigates the effects of flow regulation by the floodgate system (MoSE: Electromechanical Experimental Module) on sediment and water exchanges between the Venice Lagoon and the Adriatic Sea, during two significant storm surges in 2022 and 2023. An integrated observation system, which combines satellite-derived products and data from in-situ instrumental networks, was implemented at the three lagoon inlets (Lido, Malamocco and Chioggia). The high spatial and temporal resolution of continuous in-situ data allowed to characterize the complex interactions between sediment fluxes driven by tidal flow and the repeated and prolonged activations of the floodgates, considering the intense particle resuspension within the lagoon and along the coasts by wind waves. Our findings reveal a quite similar net sediment loss from the lagoon during each event (∼13,880 tons and ∼ 14,850 tons), but with distinct spatial and temporal patterns in the four inlet channels. During the 2022 event, sediment export during ebb tides exceeded import during floods, leading to a net loss at all inlets (Chioggia ∼ 4,720 tons, Malamocco ∼ 3,360 tons, Lido ∼ 5,800 tons). By contrast, in the 2023 event, sediment import dominated in the northern basin (Lido ∼ 5,900 tons), while export prevailed in the central and southern basins (Malamocco ∼ 6,570 tons, Chioggia ∼ 14,160 tons). As observable in satellite images, this input at north is related to fine particles resuspended under northeasterly wind along the adjacent coast and transported in the lagoon by flood tidal currents. The presence of jetties at the inlets interrupts the natural coastal drift at south inhibiting such inputs at central and southern basins. Besides being effective in preventing high waters in Venice, this study suggests that the regulation operated by the barriers can potentially determine positive or negative short-term feedbacks on the lagoon sedimentary budget, minimizing sediment losses from the lagoon or blocking the inputs from the nearby coast. In an operational context, near real-time information deriving from the tested methodology can support an effective management of the MoSE system, adaptable to the evolution of meteo-marine conditions. In the long term, adaptive strategies are essential to prevent alterations of the sediment fluxes and the consequent loss of habitat in shallow tidal environments that are already threatened by natural and anthropogenic pressures.