Landslides can have impact in Nebraska
By Dan Moser
Feb. 11, 2016, 6:45 a.m. ·
Landslides in Nebraska? Yes, they happen. And although they aren’t the dramatic type that sweep homes and people away, they do have an impact.
University of Nebraska-Lincoln geologist Duane Eversoll, author of the book "Nebraska Landslides," has spent years tracking and cataloging landslides in the state – including where they’re most prevalent and how they can be prevented or mitigated. He has recorded more than 300 landslides but says it’s likely there have been many more. During one research period, from 1981-2002, landslides caused an estimated $4.6 million in costs.
Duane Eversoll is a UNL geologist and author of "Nebraska Landslides." (Photo courtesy of Nebraska Extension)
Three factors can make an area subject to landslides.
“You have to have an area that’s prone to landslides, and we know that just by where they’re at,” Eversoll said. “Second, you’ve got to have a certain slope and it’s not as steep as you think. We do have landslides occur on very flat areas. The third thing is water, and water’s probably the biggest part of that triangle.”
Northeastern and eastern Nebraska are particularly susceptible to landslides, Eversoll said. Eastern Nebraska has glacial tills, deposits left by several ice ages, overlaid by loess. Together they create ideal conditions for landslides.
Although landslides in Nebraska aren’t likely to merit Weather Channel coverage, they do have an impact.
“You’d probably be surprised. You go over by Fremont … “There’s a big hill. There used to be four or five houses there, and a landslide took out” back yards and sewer systems, leading ultimately to the houses’ razing.
Landowners can decrease their properties’ susceptibility to landslide:
- Exercise caution in watering and placement of sprinkler systems.
- Do not place septic tanks near slopes.
- Don’t cut trees down on a steep bank to improve your view.
- Get a geological engineer to help make sure water is draining sufficiently.
A variety of methods are used to prevent landslides. In Nebraska, common methods include: improving subsurface draining and surface-water movement; flattening or modifying slopes; construction of restraining structures; filling slide areas with lighter-weight fill; and planting vegetation whose roots will provide stabilization.
Most landslides in Nebraska move fairly slowly – inches to a few feet per day – but some do occur within a few hours.