Mon June 23, 2014
Collbran Landslide Far From Finished
The Collbran landslide is far from over.
Last week the Colorado Oil and Gas Conservation Commission met with industry members and scientists to look at the current state of the slide.
"When this earth flow failed, a large mound of disturbed bedrock had rotated back and created a large depression. There's a pond in there now," said Jonathan White, a senior engineering geologist for the Colorado Geological Survey.
West Salt Creek used to flow through the valley, but now that runoff just feeds this pond, held back only by loose soil and debris.
White said that water buildup is very destabilizing, creating conditions for more landslides. What makes this even more of a problem is the amount of water that is building up.
"When you look at 15 to 30 cubic feet per second over succeeding days, we're looking at 1000 acre feet," said White.
One acre foot is an acre of land covered in a foot of water. One-thousand acre feet is approximately 500 Olympic swimming pools worth, all of which is being held back by loose soil.
They don't know how long this will last, but it will probably end one of two ways. Either the pond will grow so much that it will spill over and cut its way through the wall of dirt, draining rapidly, or the dirt will become so water logged that it will turn into mud and give way, like a damn breaking, and the pond will empty instantly.
"It's either going to happen very fast, or just fast," said White. "We simply don't know the strength of that mass of landslide material. It may be very strong and the pond could stay there for years. It could stay there so long that it becomes a marshy bench. We just don't know."
The whole area is still extremely dangerous. There are multiple sensors on the slide to monitor any movements, and it’s been still so far, but that could change at any moment.