Coastal Engineering Analysis for Airport Improvements, False Pass, AK

Abstract

A coastal engineering and numerical model (Delft3D) assessment of waves and flow was performed to support the Alaska Department of Transportation and Public Facilities (ADOT&PF) proposed extension of the False Pass Airport runway into Isanotski Strait on the eastern shore of Unimak Island. The objective of this analysis was to provide design current, water level, and preliminary wave parameters for the project site, and to assess potential project impact on tidal circulation and the wave field resulting from the proposed airport runway extension design. This study was executed by analyzing existing data, collecting new water level and acoustic Doppler current profiler (ADCP) data used to successfully validate the numerical model, and simulating 50-year design waves coupled with flow in the vicinity of the Isanotski Strait. Significant wave height simulated with a 50-year design storm range between 0.3 m and 1.1 m in the immediate vicinity of the design project extension. Moderate changes in current velocity and circulation are noted near the east side of the runway extension with current speed differences up to ±0.5 m/s.