Accepted Reports

Long-term monitoring in Prince William Sound shows lowest contamination levels in study’s history

by

Results from the Council’s efforts to monitor the long-term environmental impacts of the operation of Alyeska Pipeline Service Company’s Valdez Marine Terminal and associated tankers since the Exxon Valdez oil spill have shown oil contamination in Prince William Sound and the Gulf of Alaska has reached all-time low values. The Council has been conducting environmental monitoring since 1993.

Alyeska and its owner companies have implemented several improvements over the years which have contributed to the reduction of pollutants being discharged. These include the elimination of single-hulled tankers and Alyeska’s ability to effectively operate their Ballast Water Treatment Facility which removes oil contamination from tanker ballast water.

Read more

New study analyzes weather at Hinchinbrook Entrance

by

A recent Council-sponsored report found that wind and waves at Hinchinbrook Entrance may be under reported as observed by the Seal Rocks weather buoy.

Researchers from Tetra Tech analyzed wind and wave data to better define weather conditions at the Entrance, as well as how these conditions might affect rescue operations by the escort tugs. To do this, researchers looked at the frequency and duration of weather events when the Entrance was closed to laden tankers.

Average closure conditions

A "wind rose" graphic that shows the speed and direction of wind as recorded at Seal Rocks.
This “wind rose” graphic shows the speed and direction of wind as recorded at Seal Rocks.

Wave height alone was found to be the cause of most of the closures, occurring 10 to 26 times a year on average. Average wave height during closures was over 17 feet and the highest recorded wave was over 26 feet. Wind speed closes the Entrance one to three times annually, as do closures for both wind and waves. Winds average just over 54 miles per hour during closure and the highest recorded wind speed was over 61 miles per hour.

Closures for winds typically last less than two hours, while waves close the Entrance for an average of just over six hours.

Seal Rocks buoy’s data may not be precise

Read more

Skip to content