In the present study we describe a straightforward and highly replicable methodology to assess the anthropogenic sediment budget within a coastal system (the Northern Tuscany littoral cell, Italy), specifically selected in a partially natural and partially highly urbanized coastal area, characterized by erosion and accretion processes. The anthropogenic sediment budget has been here calculated as an algebraic sum of sediment inputs, outputs and transfer (m3) within a 40 year time interval (1980–2020). Sediment management strongly influences the sediment budget and, even if its evaluation is crucial to assess the efficiency of a coastal management policy, it is often difficult to quantify the anthropogenic contribution to sedimentary processes. Different types of intervention are carried out by a variety of competent authorities over time (Municipalities, Marinas, Port Authorities), and the correct accountability of sediment budget is no longer known, or possible, for the scientific community. In the Northern Tuscany littoral cell, sedimentation is concentrated in a convergent zone and updrift of port structures, which have determined a series of actions, from offshore dumping and disposal into confined facilities (sediment output), to bypassing and redistribution interventions (sediment transfer); conversely, river mouths and coastal areas protected by groins and barriers are subjected to severe erosion and coastline retreat, resulting in many beach nourishments (sediment input). The majority of coastal protection interventions were carried out to redistribute sand from one site to another within the study area (2,949,800 m3), while the sediment input (1,011,000 m3) almost matched the sediment output (1,254,900 m3) in the considered time interval. A negative anthropogenic sediment budget (−243,900 m3) is here documented.

中文翻译：

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沿海细胞系统的人为沉积物预算评估（意大利北部托斯卡纳）

在本研究中，我们描述了一种直接且高度可复制的方法来评估沿海系统（意大利北部托斯卡纳沿海地区）内的人为沉积物收支，特别是在部分自然和部分高度城市化的沿海地区中选择的，其特征是侵蚀和吸积过程。此处人为沉积物收支计算为 40 年时间间隔（1980-2020 年）内沉积物输入、输出和转移 (m3) 的代数和。沉积物管理强烈影响沉积物预算，即使其评估对于评估沿海管理政策的效率至关重要，但通常难以量化人为对沉积过程的贡献。随着时间的推移，各种主管当局（市政当局、码头、港务局）进行了不同类型的干预，科学界不再知道或不可能对沉积物预算进行正确的问责。在北托斯卡纳沿岸单元中，沉积物集中在港口结构的会聚区和上浮区，这决定了一系列行动，从海上倾倒和处置到封闭设施（沉积物输出），到旁路和再分配干预（沉积物转移） ; 相反，受腹股沟和屏障保护的河口和沿海地区遭受严重侵蚀和海岸线后退，导致许多海滩营养物（沉积物输入）。大多数海岸保护干预措施是为了将研究区域内的沙子从一个地点重新分配到另一个地点 (2,949,800 立方米)，而在所考虑的时间间隔内，沉积物输入 (1,011,000 立方米) 几乎与沉积物输出 (1,254,900 立方米) 相匹配。此处记录了负的人为沉积物收支（-243,900 立方米）。