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STATEMENT OF DR. ROBERT CURRY, ENVIRONMENTAL
GEOLOGIST, UNIVERSITY OF MONTANA
Mr. Curry. I am Robert Curry, and I will conclude this panel presentation. I am an associate professor of Environmental Geology at the University of Montana. I hold advanced degrees in plant ecology and geology with a Ph. D. in geology and geophysics from the University of California at Berkeley.
Beginning in February 1969, I have been deeply involved with the scientific analysis of problems associated with Arctic Alaskan petroleum development. In the early spring of 1969, while employed as a professor at the University of California, I was engaged by the Department of the Interior, U.S. Geological Survey, to conduct a reconnaissance survey of the then pending Alaska pipeline proposal and to help to formulate policy guidelines that might be used by the Department of the Interior to assure minimization of environmental impacts for the Alaskan petroleum development.
I was then serving as a scientific adviser to the U.S. Senate Public Works Committee on matters of environmental effects of offshore petroleum development prompted by the Santa Barbara oil spill and was advising the President's science advisory staff on the same matter,
Since I held a research hydrologist position with the Geological Survey and was employed part time by them and since I have lived in Alaska and studied arctic landscape processes there while employed by the University of Alaska, I was asked to begin work for Interior in April of 1969 on route selection criteria for determining environmental impact of the various petroleum transshipment and roadway schemes then being proposed and effected by petroleum companies and the pipeline consortium. This work included overflight and ground visits to the Hickle-Highway and the surveyed trans-Alaska pipeline route, and preparation of an advisory report.
Following presentation of my findings and conclusions to Interior, I began a long and intense involvement with other scientists to bring the issues into the public realm. This contributed to the preliminary injunction and long litigation in Wilderness Society v. Morton, Civil No. 928–70.
I have served in an advisory capacity in this litigation since the granting of the injunction and have prepared and digested many thousands of pages of documents on those aspects of the arctic pipelines within the areas of my expertise, namely arctic geomorphology, hydrology, and plant ecology.
I have published professional papers in these fields, specializing particularly in those geologic processes that constitute hazards to human beings and their works such as river flooding, seismic hazards, permafrost considerations, slope stability, and similar natural events.
Since 1961 I have visited and conducted field work on approximately 95 percent of the proposed trans-Alaska pipeline route from Prudhoe to Valdez and have investigated representative portions of both the Alaskan and Canadian portions of several alternative Mackenzie Valley pipeline routes as far south as Edmonton, Alberta.
I have also traveled extensively within Canada and had frequent discussions and assistance from Canadians to help me evaluate the basic data for their routes.
At this time I wish to attempt to summarize an extremely large volume of factual information on the comparative terrestrial environmental impacts of the Alaskan and Canadian pipeline alternatives. These geologic and hydrologic data overwhelmingly favor Mackenzie Valley routes.
These geologic and hydrologic data overwhelmingly favor Mackenzie Valley routes. Primary factors under consideration are seismic risk through pipeline failure associated with local ground accelerations and offsets, sea waves, slope failures, and glacier accelerations; flood and scour hazard associated with buried river crossings and glacier outburst floodways; foundation failure hazard associated with high ground-ice permafrost melting, and service and haul road substrate destruction causing increased siltation in waterways and loss of permafrost and vegetative covers.
Some serious misinformation is still being used as the basis for comments and decisions regarding the environmental impacts of the two major pipeline routes.
Although it is true that the trans-Canada route is longer, it is not at all true that there is more unstable permafrost, more chances of slope failure, equal seismic risk, or equal hydrologic risk.
Morton's letter to Congressmen of April 4 also illustrates some misconceptions about the hazard geology of the two routes, such as his ideas about design for earthquakes, permafrost, and river crossings that cause me to seriously doubt that he has the ability to grasp these technical matters sufficiently to assure his capability to attach adequate environmental and technical stipulations to any Arctic pipeline permit, no matter where constructed.
Those factual and implied errors are so overwhelmingly incorrect that they must be thoroughly challenged in open scientific forum. The following analysis will cover some of the major points of terrestrial impact.
It is well-known that the Canadian alternatives offer less seismic risk than the Alaskan route but the degree of this difference is not fully appreciated. First, the magnitude of expected earthquakes was seriously underestimated in the environmental impact statement for the longest midsection of the Alaska pipeline route, 67° north to Donnelly Dome, because earthquake of several times larger magnitudes have occurred within 30 miles of the proposed pipeline within recent historical times. The very high risk seismic zone comprises over twothirds of the Alaskan route while the lesser, 6, highest risk zone for the Canadian route is less than 120 miles in length.
About 450 to 500 miles of the Alaskan route are through areas with a conservatively determined risk of 8 to 8.5 while but one-fourth that distance in Canada has but one-thirtieth or less expected ground movement.
If we multiply length by risk factor, the longer Canadian line has but one one-hundred-twentieth the risk from ground acceleration that the Alaskan pipeline has. But ground acceleration is not the most dangerous seismic risk.
Secretary Morton assures the Congressmen that "The environmental and technical stipulations that I will attach to the Alaska pipeline permit will assure that this pipeline is designed to withstand the largest earthquake that has ever been experienced in Alaska.”
You heard Governor Egan that that was indeed the largest earthquake that we had experienced in the continental United States. I presume Secretary Morton means that the pipe will be designed to withstand ground accelerations of on the order of 1 g, or twice that of gravity.
Although it is very doubtful that this can be done for all modes of operation of a pipeline under all temperatures throughout its lifetime, even if it could be done, it would not accommodate the much larger fault offsets expectable in Alaska. Periodic fault offsets of on the order of 3 feet are not all unexpectable along each of the many traces of the Denali fault system that the pipeline must cross in Alaska.
This fault is apparently a major circum-Pacific fault bounding two plates of the earth's crust. Such faults have many traces and many fault blocks are caught between large moving masses during earthquakes. This causes local displacements much greater than the regional displacements, as was observed in Alaska in 1964 when local movement of as much as 45 feet was observed.
Much of this local displacement is vertical since the smaller blocks are wedged upward between the two blocks of the earth's crust.
Canada does not have this sort of faulting along any of the pipeline route. Nowhere have the pipeline companies or Department of the Interior demonstrated an ability to design pipelines operating at full capacity capable of withstanding 10 to 45 foot offsets that are entirely probable along the Alaskan route.
Since the highest seismic area in Alaska coincides with the area of greatest tectonic, mountain-building, activity, the highest mountains and steepest slopes are found over the foci of the largest earthquakes.
Thus, the highest ground accelerations are expected in the mountains near the sea, leading to much greater landslide and seismic sea wave hazard for the Alaskan route. Recent work by the U.S. Geological Survey and others, Boore, D. M., 1972, Geological Society of America Abstracts with Programs, page 454, has shown that previous estimates of ground accelerations to be expected near large-magnitude earthquakes were too low by factors of 5 to 10. This means that landslides, particularly landslides into the sea with associated giant sea waves up to hundreds of feet high as observed in southern Alaska, virtually certain in the pipeline vicinity within its lifetime and many parts of the pipeline and associated structures would be very much more vulnerable to these hazards in southern Alaska than Canada.
The Alaskan route differs completely from the Canadian in its close association with active coastal-zone glaciers. These glaciers are subject to surges that may or may not be triggered by seismic activity. Some of the glaciers in the vicinity of the Alaskan pipeline are known to have surged in historic time and the route passes within the area over which the glaciers traverse.
Seismic sea waves, generated by submarine ground displacements such as that associated with the 1964 Alaskan earthquake, are a particular hazard to shore installations such as that at Valdez, the terminus of the pipeline.
In narrow harbors, such as Valdez, these sea waves are particularly disastrous in that they generate waves that shoal in the confined waters and focus energy onshore; sending wash hundreds of feet above tidal range.
These are associated with earthquakes, when the partly-full holding tanks and tankers at the terminus are vulnerable to rupture. No amount of protective berms around those tanks will prevent the oil from floating off on a sea wave surge. It is not true that these risks are shared by the Canadian route. The Canadian routes from Alaska fully circumvent these high risk hazards. The Alaskan seismic risks will result in delay for construction because we cannot map all of these faults as we go along. As we detect these in the excavation put proposed for the pipeline, then it is necessary reengineer for that particular site.
Now, I would like to move to stream hazard.
Secretary Morton was again given completely false information upon which to base his information that the stream-crossing hazards are equal or greater for the Canadian route. Quite the opposite is true.
It is true that a Mackenzie pipeline route would cross more water courses, but those are generally different kinds of water courses than are crossed along the Alaskan route.
First, the so-called 12 major rivers that must be crossed in Canada are not at all similar to those in Alaska. It is true that they are large rivers in terms of flood discharge volumes, but it does not follow that they are large in width.
These large rivers would most certainly be treated just as they are in Alaska, with an elevated suspended pipeline. It is not at all implausible that a full elevated suspended pipeline would be constructed throughout the Canadian reach of the northern portion of the pipeline since that may be the least costly in terms of money and environmental damage and requires the least right-of-way. Barry Donnellan, 1972, an evaluation of the basic soil mechanics decisions on the trans-Alaska pipeline project, paper presented to the 139th Annual Meeting of the American Association for Advancement of Science, Washington, D.C., December 1972.
These large rivers would be almost impossible to tunnel beneath and would create risks as absurd as some of those proposed for stream crossings in Alaska. R. R. Curry, 1972, Comments to the Honorable Rogers C. B. Morton on the Environmental Impact Statement for the trans-Alaska Pipeline, 109 p. in Technical Comments, v. 1, Compiled by the Wilderness Society, et al., May 1972.
The Alaskan streams of intermediate and small size are generally wide and gravel-filled and flow on beds that become mobilized for many times the river's mean depths during floods. The critical Canadian rivers, on the other hand, flow on or near bedrock in narrow channels. Problems associated with burial of pipes in Alaskan streams are extreme and have not been adequately dealt with in the work of the Department of the Interior, with the exception of one USGS, paper not used in preparation of the impact statement: Emmett, W. W., 1972 Hydraulic Geometry of Some Alaskan Streams South of the Yukon River, Open File Report, Water Res. Div., Alaska.
Data presented by Emmett suggest that burial depths proposed for the Alaskan stream crossings are sometimes inadequate to accom
modate the mobile river beds to be expected and that serious problems exist with many Alaskan crossings.
In Canada, however, the generally greater distance between the pipeline route and high mountains means that fewer larger rivers will drain the majority of the regional runoff to the regional runoff to the major Mackenzie watercourse.
This means that the bulk of the tributary discharges can be crossed subaerially with advantage and that hazard is thus considerably reduced. The greater distance to the mountains and the very different nature of the glacial history of parts of the Canadian route, also accounts for the lesser depths of gravels encountered in many of the Canadian small streams.
Thus, large rivers in Canada present no more hazard than they do in Alaska, the Yukon, except that in Alaska the seismic risk to suspend crossings is greater than in Canada.
On the intermediate river risks are about comparable if pipe is to be buried, and on smaller rivers Canada affords sa fer crossings for the general case. Hazard to crossings for suspended pipelines for large rivers are very much less than to intermediate and small rivers with wide fluctuations in flow volumes and attempted pipe burial.
In Alaska, in addition, there is the compound problem of glacier dam bursts to be contended with along the sections of the route passing near and through the Alaskan range. This is not encountered along any of the Canadian route either in Alaska or Canada. These dam bursts occasioned when lakes imponded behind glaciers force their way outward suddenly, adding many times the expected discharges to small drainage channels with much scour and sediment movement. These occur in the highest seismic and landslide risk parts of the southern Alaskan route only.
While the Secretary is again technically correct when he states in this congressional letter of April 4 that the Canadian pipeline would cross nearly twice as great a length of area underlain by permafrost, based on very inadequate data from Alaska and Canada, he has been seriously misled if he believes that the Canadian permafrost will create greater hazard.
Depending upon the actual route chosen from Prudhoe Bay to the Mackenzie corridor, permafrost hazard may be equal or considerably less with the Canadian route. This is because the flanks of the Brooks Range are underlain by drier permafrost than the Arctic Coastal Plain or interior Alaska permafrost areas.
These upland dry permafrost areas post some hazard to concentrations of runoff but do not pose the thaw-instability problems that are by now well understood for the Alaskan route.
The offshore alternative doubtless has some permafrost formed during the lower glacial-age sea level stands, but this does not probably extend to depths below 100 to 200 feet and such depths are found within several miles of shore along most of the route, particularly toward Canada.
Thus, there is a potential route with very little permafrost. The Mackenzie River Valley itself has less permafrost than might be expected by comparison to Alaska since it is the locus of a north flowing river carrying huge quantities of heat northward and thawing its