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Abstract An environmental baseline study has been conducted in a large (370 km) natural and remote area of Southern Italy on behalf of an International Oil Company (IOC) to verify the potential impact of exploration and production activities. The territory is mainly mountainous and covered by forests, with limited human pressures and significant biodiversity. The study has been undertaken over a period of approximately one year. Four seasonal field campaigns have been conducted, to investigate the chemical quality of soil, waters (springs, rivers and groundwater), air and the ecological and functional quality of the river environments, with the definition of EBI (Extended Biotic Index), WSI (Wild State Index) and BSI (Buffer Strip Index). The study comprised a complex data analysis, with the use of statistical, hydrochemical and geochemical methods. Chemical analyses showed an unexpected presence of heavy metals in all the environmental matrices. Statistical and geochemical methods have been applied to evaluate this result. Principal Components Analysis (PCA) has been used to simplify and aggregate the original information with a repeatable and defensible method. Geochemical interpretation of soil sample test results was undertaken to investigate correlation of heavy metal concentrations with parameters unlikely to have been affected by human activities, such as Iron and Aluminum concentrations which are widely diffused in natural soils, and with silt and clay abundance. Undisturbed bedrock samples have also been collected and analyzed, to make a comparison with the concentrations found in soil samples. The statistical and geochemical methods applied helped to interpret the natural background abundance of heavy metals. The aim of the project was to establish an environmental baseline for due diligence purposes in a exploration site and to demonstrate that the unexpected heavy metals concentrations measured in soil and water probably have a natural origin. The application of such methods can be of general interest at exploration and production sites to define the environmental baseline prior to the beginning of the development activities.
Offshore pipelines (sealines) represent a safe and environmental friendly technology for the transportation of hydrocarbons. The technical community has dedicated a significant effort in the evaluation of environmental issues relevant to offshore fixed installations such as platforms and terminals. Minor attention has been paid to the environmental aspects relevant to offshore pipelines particularly in open sea condition. The authors have focused their attention in the identification, assessment and evaluation of environmental impacts relevant to sealines in open sea conditions. Technical and safety requirements may require the sealines either to be trenched or exposed, resting on the seabed. The environmental effects relevant to the trenched configuration are assessed and are compared against the environmental setting of the work areas. The paper addresses environmental aspects relevant to the trenching operations in view of minimizing environmental impacts on the surroundings, taking into account safety aspects as well, and disregarding economical aspects related to the two options. The aim of the paper is to outline environmental issues in order to provide the technical community with a further tool to be applied during the design decision process.
Wang, Xinggang (Nanjing Hydraulic Research Institute) | Xiong, Wei (Zhejiang Keepsoft Information & Technology Corp., LTD) | Li, Chunhui (Nanjing University of Information Science & Technology) | FU, Xiaoyan (College of Oceanography, Hohai University) | Ren, Zhuoyu (Changjiang River Scientific Research Institute)
A three-dimensional mathematical model is developed which is applied to study sediment transport under gales in radial sand ridge area in the South Yellow Sea. MIKE21 SW model is used to simulate waves under gales and FVCOM model is applied to compute currents field and sediment transport. In radial sand ridge sea area, sediments are easy to be picked up or settle down under waves caused by gales because of the properties of the sediment and hydrodynamics. In the FVCOM_SED module, bed load is classified by median particle size and the suspended sediment is calculated by three-dimensional sediment diffusion equation. The wave-tidal-sediment model is applied to the Yangkou Port in radial sand ridge sea area. The results given by the wave-tidal-sediment model show that the present model works well and could be used to simulate the sediment transport in the radial sand ridge sea area under gales.
Sediment movement in the coastal area has a huge impact on the erosion and deposition of the coast and the deformation of the beach boundary, and it will also bring about problems such as the scour of the bottom of the building and the sedimentation of the channel. Since the 1990s, a large number of scholars at home and abroad have worked tirelessly for the development of the numerical simulation of sediment transport in the estuary and coast, and made outstanding contributions in the field of sediment research. The research on sediment mathematical models has been greatly developed. In the study of suspended and bottom sand transport and river bed evolution, Luo (2004) derived a prediction formula for near-bottom sediment transport and channel sudden sedimentation under waves and currents. Horvat and Horvat (2020) applied the derived equations to develop open channel water flow, sediment transport and bed evolution models, and conducted a series of preliminary numerical tests on them. On the basis of considering the characteristics of silt and silt sand, Zhang and An (2012) constructed a mathematical model that can simultaneously simulate the movement of two different types of sediment. At present, due to the rapid development of the computer level and the continuous improvement of theoretical knowledge, sediment mathematical models are also widely used in solving various coastal and estuary dynamic problems, such as estuary regulation projects, port and waterway engineering, etc. Liu and Cai (2019) established a three-dimensional wave-current-sediment coupling numerical model to understand the sediment transport dynamics of the Pearl River Estuary. Yang and Lu (2015) established a two-dimensional mathematical model of the water and sediment transport process in the estuary coast and applied it to the Severn estuary in the United Kingdom. Li, Ouyang, Pan and Yang (2014) established a two-dimensional mathematical model of tidal current and sediment under the action of waves in coastal estuaries, which has a good application prospect. Ding, Kong and Zhu (2011) established a 3-D suspended sediment transport numerical model under combined waves and currents for the estuary and coastal areas. Zhang (2017) used the ECOM model to study the problem of sudden sedimentation of deep-water channels in estuaries under waves caused by gales. These outstanding scholars have made great contributions to the numerical simulation of sediment movement, making the sediment mathematical model play an extremely important role in the estuary and coastal area.