St. George Island Breakwater and Dredging Improvements

St. George Island Breakwater and Dredging Improvements

St. George Island Breakwater and Dredging Improvements

St. George Island is centrally located to the Bering Sea’s rich fisheries, and its small boat harbor is the primary means for vessels to access the community.

Safe mooring and navigation into and out of the harbor is frequently limited due to breaking waves and shallow water at the entrance. The breakwater has been damaged by major storms, and shoaling within the entrance channel limits draft available to the fishing fleet.

The Alaska Department of Transportation and Public Facilities (DOT&PF) hired us for a detailed engineering and environmental review to find cost-effective solutions to the harbor’s deficiencies. Work included an extensive data collection campaign collecting both upland and marine surveys utilizing state-of-the-art multibeam and ground-based LiDAR technology, wave and current data by deploying multiple Acoustic Doppler Current Profilers (ADCPs), and on-site investigations of the existing structures.

Following the data collection campaign, we performed a series of detailed advanced numerical wave modeling utilizing both spectral wave models and time-domain Boussinesq-type wave models. These models were used to help develop breakwater structural design elements for new design solutions and to compare various design configurations.

Using these data, we worked closely with DOT&PF and the community of St. George to better and more efficiently address issues and concerns with the harbor. An extensive alternatives analysis screening process resulted in a recommended breakwater extension designed to decrease wave heights within the entrance channel, thus helping to reduce the potential for vessel collisions.

St. George Island Breakwater and Dredging Improvements
Client
Alaska Department of Transportation & Public Facilities
Location

St. George Island, AK
United States