Using GNSS to Evaluate Threats to the Mobility of Resources and People on Coastal Roads in USDOT Region 10

USDOT Region 10 includes three states that have extensive lengths of coastal roads (Oregon, Washington, and Alaska). In each state, long stretches of oceanfront roads are the only way to move goods and people between coastal cities and inland population centers, which makes their potential vulnerability critical. In each of Oregon, Washington, and Alaska, coastal erosion due to high water levels and high waves is a known hazard. Roads perched on top of coastal bluffs are at risk because of undercutting from combined high water levels and waves (Olsen et al. 2009), and roads near sea level on open coasts are at risk because of changing shorelines. Our objective was to develop a new technique to assess the hazard level of coastal erosion hotspots on existing and planned coastal roadways by continuously monitoring coastal water levels and wave heights with a new remote sensing technique the incorporates the land-based Global Navigation Satellite System (GNSS). The proposed technique measures nearshore water levels and wave heights using land-based and easily mobilized GNSS, which is an all-weather, continuous, global radio satellite system.US Department of Transportation Oregon State University Pacific Northwest Transportation Consortiu