The U.S. Army Corps of Engineers’ Buffalo District Survey Team conducted project condition surveys (PCS) for the Alaska District in Southeast Alaska from June 5, 2017 through June 16, 2017, covering the Aurora and Harris harbors in Juneau, and the North Harbor in Petersburg.
The Buffalo District Survey Team has provided similar survey services assistance to several other Districts over the last 4 years, including Jacksonville, Galveston, St. Louis, Norfolk, Huntington and Louisville.
The Alaska District had a temporary need of experienced surveyors who could conduct “project condition surveys”.
A PCS is a periodic assessment of Federal navigation channels and projects, which is used for channel clearance assessment. These condition surveys are primarily used to determine if project conditions (e.g. shoaling) have changed enough to warrant maintenance dredging. Shoaling is the sand, silt, soil and other materials that builds up on the bottom of a body of water over time.
“The PCS is very important because it allows our stakeholders to determine the current condition and clearance of the navigation channels,” said Roman Figler, Chief of the Buffalo District Survey Team.
“Knowing how much available clearance there is and the draft a boat has can prevent it from running aground or being damaged.”
Each year, 2.3 billion tons of cargo (foreign and domestic) moves through U.S. ports and waterways, at a value of $2 trillion. Fifty-nine high-use harbor projects account for 90 percent of the cargo moving on the harbors and channels, carrying more than 10 million tons per year.
The survey team uses a multi-beam sonar system, which provides a full-bottom, three-dimensional mapping of the harbor. To capture the project conditions, 256 sonar beams are directed downward to the harbor floor and once the data is collected and analyzed, it is converted to a map using computer-aided drafting software.
The team is still in the process of analyzing the data, Figler said.