Journal of Waterway, Port, Coastal, and Ocean Engineering

The US Army Corps of Engineers (USACE) traditionally uses two metrics to evaluate the maintenance of coastal navigation projects: tonnage at the associated port (representing relative importance) and the controlling depth in the channel (representing operating condition). These are incorporated into a risk-based decision framework directing funds where channel conditions have deteriorated and the disrupted tonnage potential is the highest. However, these metrics fail to capture shipper demand for the maintained depth service provided by the USACE through dredging. Using automatic identification system (AIS) data, the USACE is pioneering new metrics describing vessel demand for the channel depth, represented by vessel encroachment volume (VEV). VEV describes the volume of the hull intruding into a specified clearance margin above the bed and captures how much vessels use the deepest portions of USACE-dredged channels. This study compares the VEV among 13 ports over 4 years by combining AIS, tidal elevations, channel surveys, and sailing draft. The ports are ranked based on the services demanded by their user base to inform the decision framework driving dredge funding allocations. Integrating demand-for-depth metrics into the Harbor Maintenance Fee assessment and/or Trust Fund disbursements could alleviate the constitutionality concerns and several criticisms levied against Harbor Maintenance funding.

Scour is a significant contributing factor to bridge failures, and when a bridge fails, it totally or partially loses its serviceability, causing fatalities, delays in emergency transportation and evacuation efforts, and economic losses. The mechanism of scour in riverine environment is different from those in areas under wave action, that is, coastal, and lacustrine environments. A total of 38 experiments were conducted in the laboratory under wave-alone, current-alone, and waves–current combined conditions to investigate the flow pattern and geometry of scour holes around bridge piers. Under these conditions, different flow parameters were considered and the influence of these parameters on the scour hole geometry was observed. The results showed that the combination of wave and current produced scour depths larger than those of the wave-alone experiments but smaller than those created by the current. Particle image velocimetry was used to investigate the flow field around piers and observe changes in vortex characteristics due to the change in flow conditions. Finally, an attempt was made to relate the size and shape of vortices to the scour process. It was concluded that the strength of wake vortices, the relative direction of the flow and wave, and the distances of waves from the channel bottom influenced the scour geometry and the downstream deposition pattern.

Estimating maritime climate accurately is essential to ensure the safety of marine structures. The most reliable data are in situ measurements, but due to the lack of this kind of data in both time and space, other datasets, from reanalyses and wave models, have to be used. In this study, data from the three main databases of the Spanish Mediterranean Sea used for the design of maritime structures (ERA5, Waverys and SIMAR-WANA) were compared with buoy data from Valencia, Alicante, and Cabo de Palos. A statistical analysis, using Python, MATLAB, and the Ameva tool, was performed on both the entire historic record (20,362,032 data) and the most extreme data distribution (95th percentile). Then, further analysis was performed to assess the consequences of using these datasets in the design of coastal protection and their reliability. Waverys performed slightly better than the in situ measurements and SIMAR-WANA underestimated the extreme values of significant wave height the least. Regarding the consequences on the design of coastal protection structures, the estimation of extreme events proved to be of particular interest, with the databases typically underestimating the values of extreme events, which was determined to have the potential to lead to errors in the design of coastal protection structures by up to 60%.

Recent constructions of large sea locks in the Netherlands at IJmuiden and Terneuzen have been accompanied by extensive hydraulic research, including physical scale model tests which took into account the effects of density differences across the lock heads during leveling operations. The case study presented here compares the situations and results from the studies of the two locations, and shows the importance of density effects in an accurate assessment of the hydrodynamic forces on the vessels and subsequently the forces on the mooring lines. Supposedly small differences in the local boundary conditions at the two locations lead to very different results, owing primarily to the differences in propagation of the density currents. Numerical models do not as yet predict this with sufficient accuracy. This further underlines the importance of doing extensive preliminary hydraulic investigations when designing large new shipping locks.

With the ever-increasing emphasis on climate change and sustainability, there is growing interest in using environmentally friendly coastal structures. In addition to engineering and cost factors, the construction global warming potential (GWP) can and should be an influencing factor in the selection and design of the structures. Therefore, knowledge of construction GWP facilitates informed decision-making in coastal projects to achieve climate goals. Considering the number of Icelandic-type berm breakwater (IceBB) structures worldwide, this structure's design method is commonly accepted in coastal protection projects. In this paper, the construction process of an IceBB was assessed for its GWP and compared with concrete armor unit protection of a conventional rubble mound breakwater (ConRMB). The assessment and comparison were made for constructing a breakwater to protect the port of Thorlakshofn in southwest Iceland. The life cycle assessment (LCA) methodology was applied to calculate the construction carbon footprint of the structures using GaBi software, version 10.6.1. Using the International Union for Conservation of Nature (IUCN) criteria for nature-based solutions (NBS) and based on the existing literature, the characteristics of IceBB were briefly explored. The results showed that the construction of IceBB has a lower GWP than ConRMB, mainly due to using natural rock armor instead of concrete armor units. Furthermore, the results indicated that IceBB characteristics meet the IUCN criteria for NBS and thus can be granted as a (hard) NBS coastal structure. Acknowledging the advantages of IceBB, adopting this structure in coastal protection projects could meaningfully contribute to climate change mitigating policies.