KODIAK, Alaska — Federal researchers are surveying the seafloor in Uganik Bay and west of the Kodiak Archipelago as part of an effort to update 100-year-old navigation charts.
A 50-member crew is surveying the area aboard a National Oceanic and Atmospheric Administration vessel. The ship uses a shallow-water, multi-beam sonar to collect images of the seafloor, The Kodiak Daily Mirror reported (http://bit.ly/2cFIMqS).
“We basically call it mowing the lawn,” said Capt. E.J. Van Den Ameele, commanding officer of the surveying vessel. “Every pass we make with a boat maps a swath of sea floor and then we collect the adjacent swatch and so on.”
The crew collected data from the Uganik Passage this spring and is now working on Uganik Bay as well as two areas west of Viekoda Bay and Kupreanof Straight and an area west of Raspberry Island.
The current data in some areas dates back to 1900.
“They certainly did not have the capabilities then,” Van Den Ameele said. “They did surveys with a lead line to measure depth, which was accurate for that particular position.
The crew conducts surveys for two to three months at a time throughout the year.
Van Den Ameele said they have spotted some areas that can be hazardous to mariners and are in need of an update.
“We have found some things that were not on the charts that probably should be,” Van Den Ameele said. “What we find from time to time are new shallow spots or pinnacles or rocks, and on occasion, they can be dangerous to navigation.”
It will take at least a year before the new information can be recorded in an updated navigational chart. Areas deemed hazardous will take priority and get updates sooner.
“When we do find something, we’ll immediately issue a chart correction update and notice to mariners,” Van Den Ameele said. “We want to get that info out right away.”
The current trip for the researchers began earlier this month and will end in late October.
Information from: Kodiak (Alaska) Daily Mirror, http://www.kodiakdailymirror.com