Port of Alaska, AK
eTrac has conducted 3rd party hydrographic survey services on contract for the Port of Alaska Maintenance Dredging Project since 2012. Survey services include: establishing a new GNSS control network, biweekly summer multibeam hydrographic surveys (April to November), monthly and bimonthly winter singlebeam hydrographic surveys (November to March), CAD plots and volume computations, and additional on-call services. The sea and weather conditions add a challenging component to these surveys. During the start and end of the summer season (April and November), there is generally a large amount of sea ice present in the Cook Inlet and Port of Alaska. An intimate knowledge of the local tide and weather patterns, including the tendencies of the swiftly-flowing sea ice is critical to safe and successful surveys during these periods. Careful weather assessment, awareness, and contingency plans are a vital part of these surveys during any time of the year. Due to the abundant ice in the Cook Inlet during these months, the singlebeam surveys are conducted with a 60 foot tugboat boat capable of navigating through the ice flow.
Survey data products are produced and delivered within 48 hours of data acquisition. Full-size paper and digital CAD plots contain gridded numerical soundings and a depth-colorized bathymetry image. Volumes are computed using AutoCAD Civil 3D in order to track the material removed by dredging operations and the natural accretion/erosion throughout the survey area. Digital Terrain Models (DTM) are created and submitted for each survey. This project required eTrac to coordinate a GNSS control survey, Tidal Datum mapping, multiple multibeam hydrographic surveys, and fast-turnaround high-quality data products. eTrac, now into our third 3-year contract, has mapped a cumulative survey coverage equal to over 300 square miles. eTrac’s local survey vessels and personnel are mobilized as needed in order to ensure responsiveness to a tight schedule with complete and accurate products.