Journal of Waterway, Port, Coastal, and Ocean Engineering

Yearly tidal datum statistics and tide ranges for the National Oceanic and Atmospheric Administration/National Ocean Service long-term stations in the United States tide gauge network were compiled and used to calculate their trends and statistical significance. At many stations, significant changes in the tide range were found, either in the diurnal tide range [mean higher high water (MHHW)−mean lower low water (MLLW)], or mean tide range [mean high water (MHW)−mean low water (MLW)]. For example, at San Francisco, the diurnal tide range increased by 64 mm from 1900 to 1998, while at Wilmington, N.C., the mean tide range increased at a rate of 542 mm per century from 1935 to 1999. This analysis suggests that any studies concerned with present or future water levels should take into account more tidal datum statistics than just mean sea level (MSL). For example, coastal flooding and storm damage studies should consider trends in high water levels, since it is the peak values that cause flooding and determine the design of coastal structures. For habitat restoration planning, mean low water and tide range changes should be considered.

A statistical model is developed to predict wave overtopping of extreme waves on a fixed deck. The probability density function for the volume of overtopping water is based on the truncated Weibull distribution with the assumption of a local sinusoidal wave profile. The sensitivity to the wave nonlinearity parameter and deck clearance is discussed. The statistical model is compared to laboratory data for the instantaneous free surface elevation measured in front of a fixed deck and the instantaneous free surface elevation and overtopping rate measured at the leading edge of the deck. The statistical theory compared well with the measured exceedance probability seaward of the deck. Conditional sampling of the crest heights seaward of the deck gave a normalized probability distribution similar to that of the maximum water level measured on the deck for each overtopping event. The model prediction of the exceedance probability of deck overtopping gave very good agreement for large overtopping values.

During storms, the effects of wind loading and drift currents are among the major hazards to offshore structures. In order to objectively determine overwater friction velocity and the exponent of the power-law wind profile, the concept of in-situ gust factor, which reflects the composite effect of air-sea interaction, is employed. During Hurricane Kate in 1985, pertinent meteorological and oceanographic parameters including wind speeds at the standard 10 m height were measured by National Data Buoy Center buoy 42003, located along the hurricane path at 25.88°N and 85.95°W. It is demonstrated that, during this storm, the mechanical turbulence dominates the thermal effect and the exponent of the power-law wind profile is nearly equal to the turbulence intensity in the downwind direction. Relationships among friction velocity, gust factor, and the exponent of the power-law wind profile are also found and provided for engineering applications.

The continuing growth of marine container transport and the complexity in the analysis of terminal port operations have resulted in a situation where computer simulation is mostly suited. This paper focuses on the simulated handling of incoming containers transported on trucks. It is applied on a medium-size terminal using an “All-Straddle-Carrier” system. Input data include parameters of space, speed, and arrival frequency in a generic format, thus making the model adjustable. Results on the service level, i.e., service times, utilization factors, and queues, are generated for analysis. The simulated system is used for short to midterm planning purposes, as well as a process improvement tool. A number of experiments provided the basis for evaluating case terminal performance and determining the potential for further operational improvements.

New correlations are presented for the compressibility and permeability of normally consolidated, fine-grained, marine and riverine dredged materials that are based on the liquid limit alone. They are simpler, statistically stronger, and applicable over a wider range of effective stress and permeability than comparable, earlier correlations based on the liquid limit, plasticity index, and activity of fine-grained dredged materials, mine tailings, and similar soils. However, like the latter, they must be applied with caution to sandy materials and to materials with high organic contents or that contain atypical clays with fibrous particles.