Monitoring NBS for coastal erosion and marine flooding: the Emilia-Romagna case study

The study was conducted in the context of the OPERANDUM project which is an H2020 project which aims at providing tools and methodologies for the assessment of NBS efficiency around the world. As NBS will be tested an artificial dune built with natural materials. The artificial dune is an engineered structure that will mimic the functioning of natural dunes. Its aims are reducing both natural dune erosion and flooding in adjacent coastal lowlands. It consists of a barrier between the sea and land, in a similar way to a seawall. Unlike the latter, the NBS are ‘dynamic’, i.e. the dune/beach system interacts a great deal and is constantly undergoing small adjustments in response to changes in wind and wave climate or sea level. Its construction involves the placement of sediment from dredged sources on the beach and it will be reinforced with a structure composed of biodegradable material. Different typologies of experimental solutions are foreseen. The Bellocchio Beach at Lido di Spina (Italy) was initially chosen for the study, however the Volano beach was selected as the new study area because of the strong erosion caused by an intense storm event in December 2020 at Bellocchio. The dune was built on the Volano beach and monitoring surveys were carried out on this new site. A morphological monitoring aimed to assess the beach evolution and the performance of the NBS were performed. Monitoring of morphology evolution of shoreline and inland area provide information about impact of the NBS on coastal erosion. Furthermore, the changes in the form of the work give information about the resistance of the NBS to wave attacks. Sedimentological campaigns have been planned in order to provide information regarding the texture of the sediments present in the area detected and possibly highlight changes after the construction of the dune. Three monitoring campaigns were carried out before, immediately after and six months later the construction of the dune (January, May and October 2022). All data were analysed to assess local coastal dynamics and NBS evolution. The monitoring consisted of: topographic and bathymetric surveys (GNSS and multibeam/singlebeam echosounder) to generate DTMs of the entire area (10 m cell size); aerial photogrammetric surveys by UAV for the production of orthophotos and high resolutions DTMs of the emerged beach (1m cell size) and of the dune area (0.2 m cell size); sediment sampling and grain size analysis. Surveys show that morphological and sedimentological changes are determined mostly by anthropic actions to the beach and seabed maintenance (artificial winter banks and Sacca di Goro channel). Regarding the dune area no significant changes in morphology were observed due to the limited period between the surveys. Appreciable signals were detected, such as the natural recolonization by pioneer plant species and the slight sand accumulation on the dune foot. This dataset consists of data related to monitoring activities.本研究依托OPERANDUM项目开展，该项目为欧盟“地平线2020”（Horizon 2020）框架下的科研项目，旨在为全球范围内基于自然的解决方案（Nature-based Solutions, NBS）的效能评估提供工具与方法论。本研究将以天然材料构筑的人工沙丘作为NBS的测试载体。该人工沙丘为工程化结构，可模拟自然沙丘的运行机制，其核心目标为减缓自然沙丘侵蚀，并降低邻近沿海低地的洪涝风险。它与海堤类似，构筑于海洋与陆地之间，但与海堤不同的是，NBS具备“动态性”特征——即沙丘-海滩系统会与周边环境产生大量交互，并会随着风、波浪气候或海平面的变化持续进行小幅调整。该人工沙丘的施工涉及将疏浚获取的沉积物铺设于海滩之上，并辅以可生物降解材料构成的结构进行加固。研究计划采用多种不同类型的试验方案。最初选定意大利斯皮纳利多（Lido di Spina）的贝洛基奥海滩作为研究场地，但由于2020年12月的强风暴事件导致贝洛基奥海滩发生严重侵蚀，最终改选沃拉诺海滩作为新的研究区域。研究团队在沃拉诺海滩构筑了人工沙丘，并在此新场地开展了监测工作。为评估海滩演化进程与NBS的效能，研究人员开展了地貌学监测。对海岸线与内陆区域的形态演化进行监测，可获取NBS对海岸侵蚀影响的相关信息；同时，构筑物形态的变化可反映NBS抵御波浪冲击的性能。此外，研究团队还规划了沉积学调查，以获取研究区域内沉积物的质地信息，并探究沙丘构筑后可能出现的沉积物变化。研究分别在沙丘构筑前、构筑后即刻以及构筑后六个月（即2022年1月、5月与10月）开展了三次监测工作。所有监测数据均用于分析当地海岸动态与NBS的演化情况。本次监测包含以下内容：1. 地形与水深测量（采用全球导航卫星系统（Global Navigation Satellite System, GNSS）、多波束/单波束回声测深仪），以生成全区域的数字地形模型（Digital Terrain Model, DTM），栅格单元尺寸为10米；2. 无人机（Unmanned Aerial Vehicle, UAV）航空摄影测量，用于生成出露海滩（栅格单元尺寸1米）与沙丘区域（栅格单元尺寸0.2米）的正射影像与高分辨率数字地形模型；3. 沉积物采样与粒度分析。监测结果显示，地貌与沉积学变化主要由海滩及海床维护的人类活动（如冬季人工护岸与戈罗水道（Sacca di Goro channel）疏浚作业）所主导。就沙丘区域而言，由于各次监测的间隔时长有限，未观测到显著的形态变化，但检测到了若干明显现象：例如先锋植物物种的自然定植，以及沙丘脚处少量的泥沙堆积。本数据集涵盖与上述监测活动相关的全部数据。