Engineering Disciplines


Wave Runup & Overtopping

Seawall Protection Structure, Great Highway, San Francisco, CA.

NCI conducted a physical hydraulic model study as part of the Ocean Beach concrete seawall design. Components of the seawall included a sheet pile cut-off wall, a wave rundown dispersion bench, a sloping stepped section, a wave runup dispersion bench, and a recurved wall. The hydraulic model investigation was utilized to determine dimensions and shape of the wall for the purpose of minimizing potential wave overtopping and beach scour. In addition, hydraulic loads on the wall were determined. The tests were conducted in a wave flume at the University of Florida using an undistorted scale of 1:10. Tests were conducted for variations in structural shape, beach elevations, stillwater levels, wave heights and wave periods. For beach scour tests, the sand was modelled following Lepetit and Leroy.

Seawall Protection, Mole C, King Harbor, Redondo Beach, CA.

NCI designed, constructed and operated an undistorted 1:15 scale hydraulic model to investigate the seawall improvements required to provide storm wave protection for the Portofino Inn in King Harbor. A hydraulic flume basin at the Hydraulics Laboratory of the University of California, Berkeley was utilized for constructing this model. Model test results verified final seawall height and shape requirements for the construction of a new recurved concrete seawall on top of an existing rock revetment. The selected design sufficiently reduced the amount of wave runup and overtopping, and provided adequate protection to the improvements located directly behind the Mole C revetment.


San Rafael Ave Seawall Study, Belvedere, CA.  

NCI performed the necessary investigation and analysis in order to provide design recommendations with possible alternatives to prevent wind-driven waves from overtopping the existing approximately 2,000 lineal feet of stone revetment along San Rafael Avenue that fronts Richardson Bay within San Francisco Bay.

A topographic survey was conducted for the existing San Rafael Avenue seawall and the existing installation of the revetment was reviewed.  A coastal analysis was performed for the existing baseline condition, which included (1) determining return tidal stages, (2) estimating seal level rise, (3) wind-wave hindcasting and return frequency analysis of storm wave events, (4) computing wave runup using CEDAS, SPM method, CEM method, and FEMA model, and (5) determining the coastal flood elevations based on the return tidal stage, sea level rise and wave runup.  The design recommendations and potential seawall improvement alternatives were developed based on the engineering analysis.  In Addition, the design and construction costs for the potential alternatives were developed, and the regulatory permitting requirements and potential funding sources were identified.


Foster City Levee Wave Runup Analysis, Foster City, CA.

NCI performed a levee wave runup analysis to determine the Base Flood Elevation (BFE) for a proposed levee plan at Foster City, California. The engineering analysis that was performed in accordance with the Guidelines and Specifications for Flood Hazard Mapping Partners issued by FEMA included deduction of fetch-limited wind waves and wave runup analysis based on the extreme tidal stage and severe hindcasted wind waves generated in San Francisco Bay.  Hourly readings of historical wind data for the San Francisco Airport from 1948 to 2004 were analyzed. The highest wave primarily generated by winds blowing from the northwest direction was estimated. Wave runups were predicted by using the FEMA wave runup model RUNUP2.0 for the highest wave as well as moderate waves that can be generated in the Bay.    Consequently, the 1-percent annual chance Base Floor Elevation (BFE) at the project site was determined by including both the extreme tide state and the effects of wave action.


Storm Surge Protection Wall for Gulf LNG Clean Energy Project, Jackson County, MS.

In September of 2008, Gulf LNG submitted a Federal Energy Regulatory Commission (FERC) filing which provided responses to FERC Environmental Data Requests.  The FERC filing provided detailed data that support the final design of a new LNG facility’s Terminal Seawall and supplemented the general design information that was filed with FERC.

NCI conducted the independent coastal engineering technical review of the proposed surge protection wall design and supporting documents.  The tasks NCI performed included; Investigation of the 100-year storm surge elevation and offshore storm wave conditions; review of the hurricane storm wave modeling studies; review and re-calculate the wave forces on the surge protection wall;  review the wave-induced toe-erosion; calculate the wave runup and wave overtopping on the wall; recommendation of additional wave studies, and  providing detailed written review comments on the surge protection wall design.


Wave Runup Analysis and Beach Impact Assessment For Aquatic Youth Center, Dockweiler Beach, Los Angeles County, CA.

A detailed engineering analysis was performed for the proposed (since constructed) Aquatic Youth Center at Dockweiler Beach to specifically address the characteristics of beach morphology during the winter seasons as well as on a long-term basis, and the wave runup elevations and impact on the beach during extreme storm conditions.  Therefore, the following work tasks were specifically addressed in this report; define the characteristics of the winter beach profile; characterize the long-term trend of the subject beach; analyze the storm return frequency; estimate the short-term eroded beach profiles under the severe storm conditions; computer wave runup elevations for the eroded beach profiles; assess the susceptibility of the proposed building against storm wave attack; and evaluate any adverse impacts to the adjacent beaches.

This coastal engineering assessment report described the site’s oceanographic conditions beach morphology particularly during the winter months, the storm-induced beach conditions and the resulting wave runup elevations.  It then assessed the vulnerability of the proposed Aquatic Youth Center against wave attack, and the potential adverse impacts on coastal processes as a consequence of the proposed coastal development.


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