Editorial

The state, in its quest to pave the way for a natural gas pipeline, is planning to use a high-tech technique to detect any big geological potholes along the route. The state Department of Natural Resources is taking bids on a contract to map the proposed gas line route using aerial laser imaging.

The engineers and geologists who worked on the trans-Alaska oil pipeline in the early 1970s would have loved this technology. Their work has held up well, but having this sort of tool no doubt would have given them greater confidence in their assessments.

The mapping technique relies upon Light Detection and Ranging, or LiDAR. An aircraft equipped with LiDAR flies over a route, directing laser signals toward the ground. The signals bounce back and the aircraft captures variations as data. When combined with a global positioning system and other navigational aides, the system can create extremely precise maps of the ground and anything on it.

That map can help reveal geological faults, unstable slopes, thawing soil, eroded areas and other features that need special treatment during pipeline construction.

Knowledge of these features is essential. During construction of the trans-Alaska oil pipeline, the Denali Fault through the central spine of the Alaska Range was already a well-identified challenge. So the pipeline’s builders installed special supports at the fault line. The supports worked just as designed and prevented the line from rupturing as a result of slippage associated with the 7.9-magnitude earthquake on Nov. 3, 2002.

The imaging will document a mile-wide swath along the potential gas line routes in Alaska, from the North Slope to the Canada border, as well as to Valdez. State officials say the information will be public, so it could be used for projects other than a gas line.

The $1.75 million project will be paid for mostly by the state, but the federal pipeline coordinator’s office will cover $250,000. This seems like a worthwhile investment, one that could not only assist construction of a proposed gas line but any other project in these corridors for years to come.