State needs $6 million to expand high resolution mapping of slide zones
Oct 8, 2014, 6:48 AM | Updated: 6:48 am
The image above is the SR 410 Nile Valley Landslide that occurred in October 2009. The image reflects a combination of short range, long range and airborne LiDAR data sets. The Washington State Department of Natural Resources is requesting $6.6 million to expand LiDAR mapping across Washington. (WSDOT Image)
(WSDOT Image)
The landslide disaster at Oso might finally make the case for a new multimillion-dollar program to create a high resolution map of geologic hazards across the state.
Days after the massive slide in March that killed 43 people, we saw 3D aerial images of remarkable clarity, done with a laser-surveying technology called LiDAR. It strips away vegetation to reveal telltale land deformations, faults and other hazards.
Now, the Washington State Department of Natural Resources is requesting $6.6 million to expand LiDAR mapping across Washington.
“There’s high resolution (and) low resolution. Really, not that much of it has been done at high resolution, which is what’s needed by us in the geology program, for doing some of the things that we are looking at for geological hazards,” said state geologist Dave Norman.
LiDAR mapping costs about $500 per square mile and new mapping would take several years to complete.
“But it’s well worth knowing what hazards you have out there so some mitigation can be done,” Norman added.
Counties and cities would get the LiDAR data to enhance their own mapping programs. Seattle’s senior engineering technician Gavin Schrock said the city needs more high resolution data on its numerous hazard areas. More than 1,500 documented landslides have occurred in Seattle since 1890, over 8.4 percent of the city’s land area, according to the City of Seattle.
“There’s shorelines, there’s the bluffs, there’s all the access and pipeline corridors for the water supply, quite a few of the power line corridors and around some of our dams,” he explained. “I’m kind of looking forward to the new data.”
First, Norman has to convince the state legislature to find the $6 million.
“It’s a fundamental thing that we have to have,” argued Norman, “to be able to map landslides, active faults, know how to do modeling for tsunami inundation zones.”
Since Oso, Schrock said LiDAR technology is generally known outside scientific circles.
“It’s starting to click and the general public are seeing the value in it,” said Schrock. “A lot of us have been waiting decades for this to get hip and trendy, and now it is.”
