Slip Sliding Away: Northern Kentucky hillsides gain attention

After three inches of rain fell recently over a few days in Bellevue, there was a hillside behind a row of condominiums that slid into the homes. This is just one of a growing number of landslide sites Matt Crawford from Kentucky Geological Survey (KGS) has visited in Northern Kentucky.

“I got involved in this slowly at first by compiling a landslide inventory of sites all around Kentucky with data from a variety of sources,” Crawford says. “I started visiting the sites to check the information I was putting into the database.”

Northern Kentucky has become a frequent destination for his visits, because of the high number of landslides in the region. “Our job is to communicate what we know about geology, steep slopes, soils, and about activities that destabilize slopes,” stated Crawford.

Field studies also help to verify landslide locations using light detection and ranging (LiDAR) data provided to KGS by the Northern Kentucky Area Planning Commission on behalf of the LINK-GIS partnership. Crawford explains LiDAR data is taken from an aircraft and uses pulses of light or lasers to collect very accurate terrain information. “It allows the creation of high-resolution digital elevation models,” he says, “and there are features in this data that can indicate landslide activity not easily noted by simply looking at the terrain.”

The data helped identify susceptible areas that may not have been a problem—yet. “It may have been a creeping slope that after a large rain will be more susceptible to material sliding off.”

LiDAR may not detect some landslide-related features because of development and other changes to a landscape. But field visits have confirmed landslides at many of the 234 locations indicated by LiDAR data to be a possible risk in Northern Kentucky.

Due to the geology of the Northern Kentucky area and the LiDAR data available this made the study by KGS a perfect match. Though local government and regional planning agencies have been considering whether to enact regulations relating to landslide susceptibility, Crawford says he limits his scope to geologic work.