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.

中文翻译：

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威尼斯泻湖入口处的悬浮沉积物动力学：揭示风暴潮和移动屏障操作的影响


本研究调查了在 2022 年和 2023 年的两次重大风暴潮期间，闸门系统（MoSE：机电实验模块）的流量调节对威尼斯泻湖和亚得里亚海之间沉积物和水交换的影响。在三个泻湖入口（丽都、马拉莫科和基奥贾）实施了一个综合观测系统，该系统结合了卫星衍生的产品和来自原位仪器网络的数据。考虑到风波在泻湖内和沿海岸的强烈粒子再悬浮，连续原位数据的高空间和时间分辨率允许表征潮汐流驱动的沉积物通量与闸门的重复和长时间激活之间的复杂相互作用。我们的研究结果显示，在每次事件中，泻湖的净沉积物损失非常相似（∼13,880 吨和 ∼ 14,850 吨），但在四个入口通道中具有不同的空间和时间模式。在 2022 年事件期间，退潮期间的沉积物出口超过了洪水期间的进口量，导致所有入口出现净损失（基奥贾 ∼ 4,720 吨，马拉莫科 ∼ 3,360 吨，丽都 ∼ 5,800 吨）。相比之下，在 2023 年事件中，沉积物进口在北部流域占主导地位（丽都 ∼ 5,900 吨），而出口在中部和南部流域占主导地位（马拉莫科 ∼ 6,570 吨，基奥贾 ∼ 14,160 吨）。正如在卫星图像中可以观察到的那样，北方的这种输入与在东北风下沿相邻海岸重新悬浮并通过洪水潮汐流在泻湖中传输的细颗粒有关。入口处的码头中断了南部的自然沿海漂移，抑制了中部和南部盆地的此类输入。 除了有效防止威尼斯的高水位外，这项研究表明，屏障实施的监管可能会决定对泻湖沉积物收支的正或负短期反馈，最大限度地减少泻湖的沉积物损失或阻止附近海岸的输入。在操作环境中，从测试方法中获得的近乎实时的信息可以支持对 MoSE 系统进行有效管理，以适应气象海洋条件的变化。从长远来看，适应性策略对于防止沉积物通量的改变以及随之而来的浅潮环境中栖息地的丧失至关重要，这些环境已经受到自然和人为压力的威胁。