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.

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.

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.