This map from April 4 shows areas where the Washington State Department of Natural Resources has acquired LiDAR, Light Detection And Ranging, data and areas where the agency plans to use LiDAR technology to map the geology.
Pilots have recently been flying over areas of Lewis County shooting eye-safe lasers at the ground, collecting measurements to map landslides.
The information is gathered using a 3D mapping tool called LiDAR — Light Detection And Ranging — which uses a laser, scanner and GPS. The maps can then be used for land use and disaster preparedness planning purposes.
“We just want to provide them with the best tools,” said Joe Smillie, public information officer with Washington State Department of Natural Resources.
Maps from DNR’s Division of Geology and Earth Resources last updated on Monday show LiDar readings have been taken east of Centralia and in northwest Lewis County. DNR plans to collect data from much of South Lewis County as well as areas in East Lewis County.
Smillie said with the leaves coming in, DNR has to stop doing the low areas and will move to the eastern side of the state.
He said the state is focusing on population centers as well as near Mount Rainier and Mount St. Helens due to the geological activity there.
The Board of County Commissioners will consider an agenda item at its Monday meeting to enter an interlocal agreement with DNR for the project, which is taking place elsewhere in Western Washington as well.
If approved, Lewis County will contribute $30,000 to the project to have access to the data, according to Public Works Director Tim Elsea.
“It’s just another tool we put in our toolbelt to make better decisions,” he said.
The county does have some LiDAR data, but this will offer more robust information, Elsea said, which will help the county plan for a potential disaster.
Currently there is LiDAR data in Lewis County for areas along much of U.S. Highway 12, Interstate 5 north of Napavine, state Route 6 and state Route 7.
Elsea said the county uses the LiDAR data it has anytime there is a slide or if a river moves to see what is going on under the surface.
A total of 2,424 square miles in Southwest Washington, including Lewis County, are scheduled to be mapped between 2016 and 2017. Crews began mapping 4,048 square miles of the north Puget Sound lowland and King County last year and are expected to continue mapping them this year.
The project began after the Legislature in 2015 ordered DNR to collect, analyze and distribute information about the state’s geology, focusing on landslide mapping, following the Oso landslide in 2014.
Lawmakers allocated $4.6 million for the project.
About 25 percent of the state was mapped previously, but not at a high resolution, so the mapping isn’t the most reliable, Smillie said.
LiDAR works by pointing an eye-safe laser from a plane, car or a standing platform at the ground. DNR is using planes for its project. The laser reflects off trees, buildings and other objects on the ground. The light is measured using GPS, survey stations and computer processing.
Measurement locations are created for latitude, longitude and height value, and are grouped according to what the laser hits. Models are then created and typically show the ground surface without vegetation, but models can show buildings, forest canopy and other information, according to DNR.
Other partners in Southwest Washington include Sierra Pacific Industries and the Washington State Department of Transportation.
DNR has a webpage dedicated to the project at dnr.wa.gov/lidar.
