PWSRCAC--Oil Spill Response Gap

Project Manager
Dan Gilson

907.834.5040
PO Box 3089
Valdez, AK 99686

Oil Spill Response Gap

A tanker transits rough water in Prince William Sound.

PWSRCAC believes that an oil spill response gap exists in Prince William Sound. A response gap occurs when oil can be transported in weather conditions not feasible for executing a successful oil spill response. For example, the closure limits to tanker traffic in Hinchinbrook Entrance are set at either 45 knot winds or 15 foot seas, but so far the industry hasn’t illustrated the capability to respond in weather conditions anywhere near those closure limits.

The response system in place today in Prince William Sound is the result of many years of development by industry, regulators, and PWSRCAC. Technical studies and analyses were done on response equipment and tactics based on varying weather conditions to develop the response capabilities in place to meet the response planning standard (able to contain and recover 300,000 barrels within 72 hours after a spill has occurred).

The Response Planning Group (RPG), a partnership of shipping companies, and the Alaska Department of Environmental Conservation (ADEC) recognize that the gap exists. ADEC and the RPG tried to quantify this in the early 1990s, with the result being a Realistic Maximum Response Operating Limitation (RMROL) set at 30-40 knot winds and ten foot seas with the idea that adequate prevention measures would mitigate the gap. Part of these prevention measures include tanker speed limits, ice detection strategies, and double tug escorts for each of the outbound tankers. However, the council believes that even the RMROL agreed to in the contingency plans are still unrealistic and that the gap needs to be addressed. Since better weather station data now exists, PWSRCAC is revisiting this issue. The goal of this project is to quantify, with real weather data, the frequency and severity of the response gap.

The council has hired Nuka Research & Planning LLC to assess the extent, seriousness, and possible mitigating measures of the response gap. Since they were contracted, Nuka has completed two reports characterizing the response gap for central Prince William Sound and Hinchinbrook Entrance. The mechanical response gap report analyzes the ability to respond to a spill by mechanical means, such as using booms and skimmers. The gap is compounded by such factors as sea conditions, limited visibility, human factors, and other environmental and oceanographic factors that limit oil spill response. The Non-Mechanical Response gap report addresses response gaps that exist when responding with non-mechanical means, such as in-situ burning and dispersants.

Mechanical Response Gap

Mechanical Response Gap Methods. By Nuka Research and Planning Group, LLC. May 5, 2006 (pdf/918KB)

Ideally this project would cover Port Valdez, Valdez Arm, central Prince William Sound, Hinchinbrook Entrance, Gulf of Alaska (State waters), and other Nearshore areas of the Sound. However, the response zones currently being studied will be limited by existing weather data and project funds to central Prince William Sound and Hinchinbrook Entrance.

Oil Spill Response Gap

Mechanical Response Gap

Non-mechanical Response Gap