The Wyoming Department of Transportation (WYDOT) may soon adopt technology that could give them an earlier warning when a "creeper" landslide is occurring and allows them to respond.
"Creeper" landslides move slowly over time and are not sudden events.
Aerial LiDAR uses a bunch of tiny lasers and technology similar to sonar to make a highly accurate map of an area's landscape. The number and size of the lasers allows LiDAR to penetrate vegetation, including between blades of grass, to get a true reading of the height of the ground.
That map can be used to detect potential landslide activity like cracks or tilting and allow WYDOT employees to take action.
"They [the geologists] have different methods for managing landslides, it depends on how big it is. Sometimes they can develop fixes for them with different geotechnical means, but sometimes, if it's big enough, it just has to be managed over time," John Goyen, the state's photogrammetry and surveys engineer, said.
LiDAR is much more accurate and easier than aerial photography.
"With aerial photography, we considered that, but because of the amount of vegetation that grows up there in the summer, the ground is obscured and unlike LiDAR aerial photography has a hard time penetrating all the vegetation," Goyen said. "So, it's going to leave a lot of void areas where we cannot see the ground - it just gets obscured. And so then we have to get surveyors out there to fill those places in."
It's also safer and easier than in-person surveys.
"Just to have boots on the ground and have surveyors walking up and down very, very rough, bear-infested terrain is pretty difficult. To cover that much area, it would take a long time and lots of man-hours," Goyen said.
WYDOT has completed two aerial LiDAR flyovers of three areas near Yellowstone that have a lot of landslide activity. They plan to complete a third this summer and compare the data to see how much and how fast material is moving.
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