Analysis Of Crude Oil Tanker Ballast Water Data For Valdez And Prince William Sound, Alaska

Executive Summary: This report describes ballast water source and management data reported by crude oil tankers arriving to Valdez and Prince William Sound, Alaska from 2005 through 2012. The analysis includes the following: Annual number of vessels that discharged ballast water, Annual volumes of ballast water discharge, Ballast water source locations, Ballast water management locations, Ballast water management rates, Ballast water management methods. Between 2005 and 2012, 18 crude oil tankers reported discharging 54,642,270 metric tons of ballast water to Valdez and Prince William Sound. The majority of ballast water was sourced from locations on the west coast of the United States, such as Anacortes, WA, Benicia, CA, and Bellingham, WA, resulting in 97% coastwise ballast discharge. The remainder (3%) was sourced from distant locations such as Hawaii and Singapore. Of the 28% of ballast water that was reported to be managed, flow-through ballast water exchange was the preferred method (71%), followed by empty-refill exchange (27%), and alternate methods (2%). Trends in data should be considered in the context of changes in policy during the time period. For example, the Environmental Protection Agency?s 2008 Vessel General Permit (VGP) significantly changed the management and record keeping requirements for crude oil tankers involved in coastwise trade. The VGP went into effect in Alaska on February 6, 2009.