In hydraulic model tests, it is common practice to relate the response of the tested structure to the incident wave parameters at the toe. Estimation of the incident wave parameters at the toe is thus an essential part of the analysis of hydraulic model testing. In many cases, the design conditions at the toe are given by waves that are highly nonlinear or even depth limited. Modelling such conditions requires reproducing the prototype foreshore slope in the model. The present paper provide guidelines on the accuracy of a nonlinear reflection separation algorithm when applied to nonlinear waves over sloping foreshores. A simple methodology has been established to estimate the expected errors on the incident wave parameters.
The idea for this project originated within the Arctic Council’s Protection of the Arctic Marine Environment (PAME) Working Group, where a concern was raised about the disposal of tailings from onshore mining operations onto the seafloor. This led to a broader reflection on the impacts of mining operations on the marine environment. Many Arctic governments support the development of a mineral extraction industry, provided it operates in an environmentally responsible manner and considers socio-economic impacts to local communities. However, the environmental impact of existing and future mining operations is often debated. This report summarizes the results of the multi-year Existing Waste Management Practices and Pollution Control for Marine and Coastal Mining project, developed under the auspices of the Protection of the Arctic Marine Environment (PAME) Working Group.
The space occupied by traditional and new human-based marine uses at sea is expanding, creating a need for developing methods to assess interactions between co-located uses in maritime spatial planning (MSP). However, no clear terminology for use-use interactions exists. Thus, an analytical framework for spatial decision support tools (DSTs) to assess use-use interactions is deduced from literature. Four spatial-temporal links are found to either alone or together constitute use-use interactions: location links, environmental links, technical links, and user attraction links. It is found to be important for DSTs to support co-location management in MSP by iteratively through the MSP process 1) spatially-temporally locate spatial-temporal links constituting use-use interactions, 2) list conflicts and synergies of the located use-use interactions, and 3) weight the conflicts and synergies. With this analytical framework, two types of DSTs are analysed for their ability to include co-location; matrix- and ranking-based DSTs to detect conflicts and synergies and space allocating DSTs to avoid/minimise conflicts and optimise synergies. Whereas the first group of tools categorise or rank use-use combinations, the latter group use information about which multi-use combinations are possible as pre-existing knowledge, and thus the two groups of DSTs can advantageously be used together. A discrepancy is found between the co-location framework and the DSTs. It is argued that future tools could work on removing this discrepancy by considering the spatial-temporal links of use-use interactions, strengthen the focus on synergies, as well as prioritize ranking of synergies and conflicts over binary approaches that only evaluate spatial compatibility.
Automated fish documentation processes are in the near future expected to play an essential role in sustainable fisheries management and for addressing challenges of overfishing. In this paper, we present a novel and publicly available dataset named AutoFish designed for fine-grained fish analysis. The dataset comprises 1,500 images of 454 specimens of visually similar fish placed in various constellations on a white conveyor belt and annotated with instance segmentation masks, IDs, and length measurements. The data was collected in a controlled environment using an RGB camera. The annotation procedure involved manual point annotations, initial segmentation masks proposed by the Segment Anything Model (SAM), and subsequent manual correction of the masks. We establish baseline instance segmentation results using two variations of the Mask2Former architecture, with the best performing model reaching an mAP of 89.15%. Additionally, we present two baseline length estimation methods, the best performing being a custom MobileNetV2-based regression model reaching an MAE of 0.62cm in images with no occlusion and 1.38cm in images with occlusion. Link to project page: https://vap.aau.dk/autofish/.
The present paper deals with overtopping prediction for berm breakwaters in line with the EurOtop methodology. The basis for the paper is the recent advances proposed for EurOtop for conventional breakwaters with respect to the influence of the wave steepness and the crest width. New model tests have been performed to investigate the applicability of these influence factors to berm breakwaters. To cover a white spot in existing data for berm breakwaters, the model tests included wave conditions with very low wave steepness. The results show that the recently developed influence factors for conventional breakwaters also improve predictions for berm breakwaters. Based on this, an additional influence factor for the dimensionless berm width is established. The berm width was in previous studies made dimensionless by the wave height, but the present study indicates that the wavelength is more appropriate.
Maritime Spatial Planning (MSP) requires a spatially explicit framework for decision-making, and on that background the overall objective of BONUS BASMATI is to develop integrated and innovative solutions for MSP from the local to the Baltic Sea Region scale. This is to be realised through multi-level governance structures and interactive information technology aiming at developing an ecologically and socio-economically sound network of protected marine areas covering the Baltic Sea. Based on the results of former MSP projects, the BONUS BASMATI project sets out to analyse governance systems and their information needs regarding MSP in the Baltic Sea region in order to develop an operational, transnational model for MSP, while maintaining compliance with existing governance systems. It also develops methods and tools for assessments of different plan-proposals, while including spatially explicit pressures and effects on maritime ecosystem services in order to create the Baltic Explorer, which is a spatial decision support system (SDSS) for the Baltic Sea region to facilitate broad access to information. During the project running until 2020, new data will be produced and tested in assessments corresponding to policy goals. The data will support the combined analysis of the three elements of the concept of ecosystem services: the capacity, flow and benefit of provisioning, regulating and cultural services. A central aim of the project is to facilitate cross-border collaboration, and the project is carried out in close cooperation with relevant stakeholders in the BSR. The impact of the project will be facilitated and assessed in transnational case studies, where integrated solutions are required. The local scale will consist of case study areas in the South-West Baltic, the Latvian territorial and EEZ waters including open part of the Baltic Sea and the Gulf of Riga, and across the region, a pan-Baltic case study will be performed.
Determination of the causes of mortality in stranded marine mammals can contribute valuable information for conservation of wild populations, as well as contribute to risk assessments for different pathogens, hosts, and environmental conditions. This study examined necropsy reports for harbor (Phoca vitulina; n = 213) and gray (Halichoerus grypus; n = 40) seals stranded in Denmark in the period 2014 to 2021 to determine the causes of mortality where feasible. The likelihood that human interactions did or might have contributed to the mortality was also assessed. Infection with lungworms, heartworms, gastrointestinal roundworms, and influenza virus was tested for each seal in the data. Parasitic bronchopneumonia was the most common cause of death in both harbor (n = 68) and gray (n = 8) seals, and significantly more juveniles than adults died as a result of parasitic infections in the harbor seal cohort. Starvation was also a major cause of death in juvenile seals. Cause of death, death class (found dead, euthanized, or culled), and whether human interactions played a role in mortality did not vary significantly between the two species. Traumatic causes of death, resulting from confirmed or probable human interactions, were associated with adult and subadult seals of both species. Culling was the cause of death for 13.6% of harbor seals and 17.5% of gray seals.
This paper analyses challenges and enablers for integrating a transboundary land-sea interaction (LSI) perspective into marine spatial planning (MSP) practice as experienced in the Baltic Sea Region. Collaborative research results from the Pan Baltic Scope project indicate that LSI remains an amorphous concept, particularly within a transboundary MSP context. Difficulty lies in bridging planning practices across land and sea and between varying uses, administrative settings and governance functions. Addressing LSI requires capacity, time, resources, awareness, reflection, and forums for collaborative learning across sectors and governance levels.
To clean the produced water is always a challenging critical issue in the offshore oil & gas industry. By employing the plant-wide control technology, this paper discussed the opportunity to optimize the most popular hydrocyclone-based Produced Water Treatment (PWT) system. The optimizations of the efficiency control of the de-oiling hydrocyclone and the water level control of the upstream separator are discussed and formulated. Some of our latest research results on the analysis and control of slugging flows in production well-pipeline-riser systems are also presented. The ultimate objective of this research is to promote a technical breakthrough in the PWT control design, which can lead to the best environmental protection in the oil & gas production, without sacrificing the production capability and production costs.