Tundra travel quandary

Alaska seeks to protect both North Slope tundra and winter exploration: field work tests just completed, results will be released in November

Kristen Nelson

Petroleum News Editor-in-Chief

The Alaska Department of Natural Resources is responsible for opening and closing state lands on the North Slope for off-road tundra travel each winter. Since the state began setting a tundra opening date 34 years ago, the window for on-tundra work has shrunk from more than 200 days to around 120.

The department’s Division of Land, Mining and Water has just completed field work testing the tundra impact of different vehicles at different times from fall through early winter. Results are expected in November.

The division is also completing a study on how the tundra opening determination has been made over the years, and evaluating the economic impact of the reduction in the number of days the tundra is open.

Results of the field study will provide scientific data.

It will be, says Harry Bader, the division’s northern region land manager, the first time the state has ever had a scientific basis for its tundra opening decisions. And it’s not an academic exercise. The division has been given a mission, he said: to extend the on-tundra work season while maintaining — or exceeding — the current level of tundra protection.

The number of days allowed for winter tundra work has dropped significantly since the state began to set the tundra opening date in 1969, and a chart of that decline, Bader said Aug. 1, prior to a tour of some of the division’s tundra test plots, has been widely used to illustrate climate change.

And “part of this project is to tease out how much of this graph is a result of climate change and how much is the result of management choice.”

Bader said he hopes to find that a fraction of the changes in the tundra opening dates are due to management choice, “because if it’s entirely climate driven, I’m going to have a hard time opening up the season.”

The $1 million study

The division is studying a number of things in what is, Bader said, “the first-ever test on the tundra in a controlled environment.”

One question being asked is “what is the level of disturbance under our current standard?” Public consensus seems to be, he said, that the current level is acceptable. Measuring that level of disturbance is significant, because the division has been asked to change how it opens the tundra so the season will be longer, while maintaining — or enhancing — the present level of tundra protection.

Bader said he wanted people outside the system for the study, and chose to go with academic interns, most of them graduate students, from the University of Alaska Fairbanks, the University of Oregon Law School, McGill University in Canada and Yale University.

Two test areas

The Foothills site is dominated by tussock shrubs, he said, while the coastal plain site is 90 percent wet sedge meadow.

The test work was done over the fall and winter season, and included five treatments on six dates, for a total of 30 plots at each site.

In the treatments vehicles were driven in a figure eight pattern on the plot. The ground was staked to indicate the pattern. Treatments were: a trucker, a wheeled front-end loader, a D-7 cat tractor, a challenger (a rubber-tracked vehicle) and a “no-treatment” treatment.

The “no-treatment treatment” is not the control, Bader said. The control was the baseline ecological data that he and interns working on the project collected the summer before the tests.

The “no-treatment” treatment “is to calibrate the natural variation in change that occurred in the tundra” Bader said. To be significant, any change in the area driven over by, for example, the D-7 Cat, compared to the baseline, “has to be statistically significantly different than the change that occurred in the no-treatment treatments for the same time period.”

Measurements crucial to study

Before the driving tests, measurements were made of snow depth, snow slab thickness, hoar frost thickness and ground hardness.

Ground hardness is measured with a drop hammer. One person lifts a weight and drops it; a second person is on the ground, recording how many drops it takes for each inch of penetration by the probe to a depth of 12 inches.

For the vehicle treatments, each was driven over a figure-eight course, marked by stakes.

Bader said the tests, which included 10 passes through the cross “gate” marked by stakes in the center of the figure eight, exceeded anything the division would allow companies to do on the tundra in terms of repeated driving over a single spot.

For each test date, each vehicle was driven in a figure eight pattern on a separate plot; then the plots were left alone. For the next test date, vehicles were driven over different plots.

This enables the division to compare both the date of the test (and the snow and ground hardness conditions on the test date) and the results from different vehicles.

October represents “worst case”

This summer Bader and interns Jacynthe Guimond, a graduate of McGill University, in Montreal, Quebec, and University of Alaska Fairbanks undergraduate Jonathan Fiely, returned to the test plots. They took measurements of tussock frequency and disturbance; shrub frequency and disturbance; vegetative cover; depth of active layer; soil temperature at depth; soil volumetric water at depth; and microthermography.

One test, measuring plant stress, used a device developed to measure plant stress on golf courses.

This project will wrap up with modeling, but Yale has applied to the Department of Energy for money to monitor the plots over a 20-year period.

Bader said just entering the data for computer analysis will take 175 to 200 hours.

Has he found a way to increase on-tundra time? Bader says he doesn’t know: look for results in November.

Tundra opening tools have changed

Kristen Nelson

When Harry Bader took over as northern region land manager for the division in 2002, he had a study done of the division’s decision-making processes. One outcome of that study was a recommendation for further analysis of the decision making behind the tundra opening.

As with the tundra plot work, Bader wanted people working on the project who don’t, as he put it “have a dog in the fight.” He chose academic interns: University of Oregon law student Patricia Bradwell; University of Alaska Fairbanks graduate student Sherri Wall, a Ph.D. candidate in economics; and Alison Macalady, a master’s degree student at Yale University School of Forestry.

They studied how the state made tundra opening decisions in the past, and what the economic cost is to the state of a shorter tundra opening.

Institutional history, transparency

Tundra opening, Bradwell said, “is a product of a variety of factors including climate variability, the measure techniques that DNR has used to determine the frost level and ground hardness of the tundra, and also changes in the way that DNR decision makers have valued the tundra ecosystem over the years.”

The assumption at the beginning of the study was that the state had always used the 12 inches of hard ground and six inches of snow standard for determining tundra opening. What they discovered was “that that standard was applied in a number of different ways over the years, and in some cases it wasn’t applied at all.”

General guidelines have changed a lot.

The 12 and six guidelines were developed by Max Brewer, formerly director of the Naval Arctic Research Laboratory in Barrow, in advising the U.S. Geological Survey and the U.S. Navy on construction of airplane landing strips, roads and drilling pads on permafrost. In conversations with Brewer, Bradwell said, “it became clear that the 12 and six standard was less of a scientific standard than it was an engineering rule of thumb.”

What the state actually relied on, however, has varied a lot: from 1969-82, air temperatures at Barrow and Barter Island were the basis for tundra opening. From 1982-84, the state also measured the thickness of ice on rivers, or asked oil companies working in the area to measure it. In these early years, Bradwell said, there wasn’t a budget for state staff to go to the North Slope to take measurements.

In 1985, however, the state started directly measuring tundra hardness: driving a graduated steel rod into the frozen ground with a sledgehammer. In 1993, the state began to experiment with different techniques to take measurements, and in 1995 began using a slide hammer: as the hammer was dropped down the weight would push the point into the ground.

There were problems with both the sledgehammer and the slide hammer, however, because the number of sledgehammer strokes — or the number of drops of the slide hammer — depended on the strength of the person doing the measuring, and the slide hammer often required application of additional pressure to drive it into the ground. And that affected the measurement of how hard the tundra was.

Bader helped develop the drop hammer, in use since 2002. The drop hammer has a probe which is both harder and slimmer than that used on the slide hammer, so it can penetrate the ground service without additional pressure, so the strength of the person operating the equipment doesn’t affect the measurements.

Economic implications of tundra season

Most exploration is done from ice roads and ice pads: they take time and cost money to build. Wall said she was told that $100,000 a mile is a good estimate for ice road costs. Taking 60 miles as an example, that’s $6 million just to put in the ice road, and then you have to drill. If you can only drill one well from that ice road, because of the shorter tundra season, that adds $6 million in cost to a single well, whereas if you had time to drill two or three wells the cost could be split between the projects, she said.

And what are the oil companies saying? Anadarko Petroleum told Wall: “Alaska’s a difficult place to do business, given the lack of access to infrastructure and cold weather. The shortened season is considered for fund allocation. There is no doubt that there have been many decisions that our dollars are better spent taken elsewhere.”

And ConocoPhillips, in recent years the most active North Slope explorer, said: “We have more projects than money and we must consider where we can most efficiently spend our money. So Alaska is in a disadvantaged position to compete, given the seasonal operations. Exploration is teetering on the brink of extinction.”

If there is no exploration, then production declines as existing reserves are produced.

Oil royalties and taxes account for 84 percent of the state’s general fund revenues. In 2003, royalties were $1.2 billion and tax, severance and other payments by the industry were $800 million, Wall said. Alaska provides 19 percent of U.S. oil production, so as the tundra season shortens, “there are economic implications not only to the oil companies themselves, but also to Alaska’s fiscal stability and national energy security.”