How to read a wind rose: This graphic, referred to as a “wind rose,” helps researchers visualize average wind direction, frequency, and speed. This rose represents all of the data for June 2020. The bars point toward the direction the wind is blowing from, the length represents the frequency of wind from that direction, and the color indicates wind speed. This particular rose shows that winds during June 2020 were generally from the west and some were from the east. The strongest winds came from the west and were between 10 to 20 knots (approximately 11.5 to 23 miles per hour).
A new study will help responders plan for the effects of weather on an oil spill. Dr. Rob Campbell, a researcher at the Prince William Sound Science Center, has been working with the Council to collect data about ocean currents, wind direction and speed, wave direction and heights, and other information from two buoys in Prince William Sound.
The buoys have been in place since 2019, and have collected enough information to begin to analyze trends. Dr. Campbell recently analyzed the nearly two million pieces of information.
Dr. Campbell found that the air and water temperatures generally followed a typical annual cycle for a subarctic region. Highest temperatures were seen in August, and the lowest in February. There were a few deviations, however:
During the summers of 2019 and 2020, the region experienced a marine heatwave, referred to by locals as “The Blob.” These unusually warm temperatures matched what was occurring in the Gulf of Alaska.
Late 2020 brought impacts from a La Nina event. La Nina is a climate pattern associated with cooler temperatures in the Pacific Ocean.
Regional temperatures increasing
Temperature data has been collected in the region since 1908. Dr. Campbell was able to compare this historical data with data from the buoys to confirm a warming trend of approximately 5 degrees Fahrenheit over the last 114 years.
Surface temperatures trending warmer in winter, cooler in summer
Interestingly, in the last few years Port Valdez has experienced cooler than average temperatures at the water’s surface during summer. This appears to be related to melting glaciers, which have been melting much faster in the Gulf of Alaska region than the rest of the world. Most of this melting happens between May and October. Cold water from the Lowe River and Valdez Glacier Stream flows into the port, cooling the water’s surface.
How does this affect oil spill prevention and response?
Understanding how factors such as wind, waves, currents, and temperatures are behaving and changing can help responders better prepare for an oil spill, and make sure spill contingency plans are tailored to real conditions in the region. Real-time weather data can also provide valuable information during a spill response.
The oil spill contingency plan for the Valdez Marine Terminal is undergoing its five year renewal. During a public comment period in December, the Council voiced concern over a “prevention credit” that reduces the amount of oil that the industry must be ready to clean up if a spill were to occur.
One of the Council’s primary duties is reviewing spill contingency plans for the oil industry in Prince William Sound. The Council has been reviewing these plans since 1990.
“Over 30 volunteers, staff, and contractors spent hours reviewing documents and coordinating these comments,” noted Linda Swiss, the Council’s project manager for contingency planning. The three volumes that make up the oil spill contingency plan for the Valdez Marine Terminal contain over 1,000 pages in total.
What’s in a contingency plan?
Oil spill contingency plans contain details about the steps to be taken before, during, and after an oil spill.
Before: what’s being done to prevent an oil spill
During: how the industry will respond to an oil spill, including where the equipment and personnel would come from
After: plans are updated to reflect lessons learned from previous spills
“These plans are a good way for stakeholders to understand how their resources and livelihoods are protected,” Swiss says.
Oil spill contingency plans are prepared by the operators of Alyeska’s marine terminal and oil tankers and are subject to state approval.
There are separate plans for spills from the Valdez Marine Terminal and from the tankers that load crude oil at the terminal. Plans undergo an update, review, and approval process approximately every five years.
Liners under crude oil storage tanks still of concern
The crude oil storage tanks at the Valdez Marine Terminal are surrounded by massive asphalt-lined cells that are designed to contain oil in case of a spill from a tank. The cell walls can be seen in this photo. Photo by Linda Robinson.
One of the central issues the Council is concerned about is an asphalt liner surrounding the large oil storage tanks.
Each tank holds approximately 23 million gallons of oil. If a tank were to leak oil, the liners act as a backup system that is supposed to contain the oil until it can be cleaned up and before it can contaminate ground water or Port Valdez. The backup or “secondary containment” system consists of a huge bowl-shaped area around the tank. The area is lined with asphalt, which is buried under several feet of gravel.
Why does the Council care about this liner?
The Exxon Valdez oil spill taught the lesson that a certain amount of equipment and trained personnel must be on hand to respond quickly.
The amount of response equipment and personnel varies according to the storage capacity. At the terminal, this is based on the maximum amount one of the oil storage tanks can hold, which is approximately 23 million gallons.
Alyeska receives a 60% “prevention credit” for various prevention measures. Most of that 60% is for having the asphalt liner around the tanks. This means they plan for a spill of 40% of the total volume of one tank, which is 8.5 million gallons. If more than 8.5 million gallons is spilled, they would still be responsible for cleaning it up, however, more equipment would be needed than is currently listed in the plan.
Is the liner still intact?
This liner was installed when the terminal was built and is approaching 50 years old. From time to time, sections of the gravel layer over the liner have been removed when work is done for other projects. When this is done, cracks and holes are often found in the liner.
“There are crude oil storage tanks holding half a million barrels of oil sitting on a steep slope above Port Valdez within a secondary containment system with known integrity issues,” the Council noted in their comments.
Testing the liner
Because the liner is buried under gravel, it is expensive and time-consuming to dig it up for a visual examination. Excavation could also damage the liner. In 2022, the Council conducted a study of methods to evaluate the liner without removing the gravel. Alyeska is planning to conduct a pilot test this summer using an approach similar to the method recommended in that report.
What is a prevention credit? Spilled oil can never be completely recovered, so regulations are designed to encourage companies to prevent spills from happening in the first place. One way to do this is to give “credit” for prioritizing spill prevention.
In Alaska, the amount of equipment and personnel that an oil company must keep on hand to respond to a spill depends on the potential size of a spill. If a company takes actions to prevent or reduce the risks of a spill, they can qualify for such a credit. This allows the company to keep less equipment and personnel on hand to respond, because a spill is less likely.
Additional issues
The Council noted several issues aside from the liner, including:
The length of time between internal inspections of the storage tanks.
A lack of detail about the training to prevent oil spills.
Documents containing plan information that were not made available as part of the public review.
The oil spilled in 1989 (pictured above) was “heavier” than the oil flowing through the Trans Alaska Pipeline today.
Crude oil is often referred to as a “fossil fuel” because it is made up of plants and animals that lived millions of years ago. Over time, these remains were exposed to heat and pressure inside the Earth’s crust, forming crude oil.
This process is full of variables. The organic materials that make up one pocket of oil can differ from another, or the deposit could have been exposed to different pressures or temperatures during formation. These variables mean oils have different properties such as density, viscosity (thickness), or tendency to form an emulsion.
The oil pumped through the Trans Alaska Pipeline System is a mixture from different fields. That mixture changes over time. The properties of oil can change as the field ages, and new fields are brought into production.
These variations mean the oil behaves differently. It can flow faster or slower, or evaporate more readily.
These, and other variations, influence the techniques used to clean up a spill.
Approximately every five years, the Council obtains a sample of crude oil from the Trans Alaska Pipeline System for analysis. Researchers look at properties such as weight, evaporation, and emulsification. A new report summarizes the latest findings.
Weight
A “heavy” oil is denser than a “light” oil, which flows more easily. Heavy oils are more useful for asphalt and plastics, while lighter oils are processed into gasoline and jet fuel.
When the pipeline first started transporting oil, the oil was considered “heavy.” In 2010, a sample analyzed by the Council found that the oil had lightened considerably. The trend continued in 2015 and again with this recent sample, although the shift has not been as dramatic since 2010. The most recent analysis categorizes the oil as a “medium” viscosity.
These properties may affect response tactics. For instance, if spilled, lighter oils may be easier to pump, however lighter oils could spread more rapidly, covering a larger area.
Evaporation
Lighter weight oils are made up of substances that evaporate more easily. A fuel such as gasoline can evaporate completely at temperatures above freezing. In crude oil, however, evaporation of lighter molecules leaves behind heavier components of the oil. The heavier oil components emulsify more readily.
Emulsification
Emulsification is the process by which one liquid is dispersed into another one in the form of small droplets. Mayonnaise is an example of an emulsion: oil, water, and egg yolks are whisked together to form a thick paste, with the egg serving as the emulsifier to keep the oil and water from separating. In a similar fashion, ocean waves and wind can mix water droplets into spilled oil.
Some emulsified oils break down and separate back into oil and water over time, however in heavier oils, this mixture can stabilize, becoming permanently emulsified.
Emulsified oil is much more difficult to clean up. The volume can triple in size and become almost solid. If the emulsion stabilizes, it is difficult or impossible to recover with a skimmer.
Oil samples analyzed by the Council prior to 2001 formed stable emulsions when weathered. Tests performed on the recent sample found that the newer oil will emulsify, but does not stabilize into a permanent emulsion.
Report available online
The tests on the sample were conducted by Environment and Climate Change Canada. Dr. Merv Fingas interpreted the lab results, which are summarized in the new report:
The Council would like to see more exercises performed during low-visibility conditions. If a spill were to occur during winter or a foggy summer day, crews don’t have as much practice in how to adjust tactics for these conditions. Photo by Jeremy Robida.
For the past few years, the COVID-19 pandemic affected many aspects of daily life. Oil spill drills and exercises were not exempt. Restrictions to protect the health and safety of responders limited these activities.
Not only were there fewer drills and exercises, they were harder to observe. Social distancing meant that Council staff could not board tugs and barges to see response operations up close. Council staff members Roy Robertson and Jeremy Robida, who have monitored drills and exercises in Prince William Sound for the past 18 and 13 years respectively, conducted some observations from a separate chartered vessel.
Fortunately, this year many of the restrictions were lifted.
New report summarizes 2022 drills
The Council’s annual report on drills and exercises conducted in Prince William Sound in 2022 has been released. The report highlights some of the continuing effects from the pandemic, along with a few changes that are here to stay.
Conducting business online
Virtual conferencing has changed many workplaces, including oil spill response. These technologies have shown up in several ways.
Coordinating online: Many drills are now hybrid (in person with online participants). Meetings are broadcast on videoconferencing platforms. Documents and other data are shared through online collaboration tools. Robertson says there are still some glitches, but these are improving.
Live video streaming: During a drill in May, the Alaska Department of Environmental Conservation deployed a drone over some activities out on the water. They were able to stream live video to the Valdez command center and participants in Jacksonville, Florida. The video was also recorded and available for later review.
Online training options: Alyeska’s Ship Escort Response Vessel System conducts annual trainings for crews of local fishing vessels, who are contracted to respond in case of a spill. Before the pandemic, part of the training sessions were held in a classroom, part were hands-on experience with equipment on dry land, and finally, crews would practice deploying equipment on the water.
Since the pandemic, the classroom sessions have been held online. The dry-land portion that required closer physical interaction between participants had not been held since 2020, but returned in 2023. The on-water portion remains the same.
Improvements at Valdez Duck Flats
Pandemic restrictions particularly affected exercises to practice either diverting oil from shorelines or protecting locations that are particularly sensitive to oil contamination, such as hatcheries. These tactics are performed by fishing vessels which have little room for social distancing. The return to in-person exercises is important for these activities.
Robertson noted in the report that responders spent more time this year practicing tactics to protect the Valdez Duck Flats, a highly productive biological area that provides critical habitat for a variety of waterfowl, small mammals, and marine mammals. This area is particularly sensitive to oil contamination. This was time well spent, he says. Robertson said that the responders have become more proficient at these tactics.
