Toe Jam Hill on Bainbridge Island rises as a paramount challenge for cyclists touring the scenic island’s south end, with a grade so steep that a popular club-sponsored ride each February no longer includes it on the route. Any riders who still take on Toe Jam are likely to have no idea that, right under their wheels, a violent earthquake lifted the ground 23 feet when it struck a millennium ago.
Geologists did not know of the Toe Jam Hill fault either until the late 1990s, when advanced light pulse technology unveiled the huge subterranean crack, one of the largest of many underlying the Puget Sound region. The fault was detected using technology called lidar, for Light Detection and Ranging, a sophisticated form of aerial photography. Lidar sends piercing laser beams to the ground to collect data used to drawing high resolution, three-dimensional geographic representations of the earth below.
Lidar is just one of the many tools that are increasingly being harnessed by Geographic Information System (GIS) professionals working in state, local and tribal governments in Washington. A coordinated, statewide lidar strategy will be among the many topics to be discussed during the 7th annual Joint Agency GIS Day event on Nov. 14 in Olympia.
The annual event at the 1500 Jefferson Building, co-coordinated by WaTech's Office of the Chief Information Officer, gathers GIS professionals and policy makers from across the state. They will learn the latest in geographic data management, especially as it applies to sharing mapping technologies to make critical decisions about land use and assessing risks when locating infrastructure like airports, sewer lines, highways and housing developments.
Lidar technology is used not only in planning for the potential of future earthquakes along known fault lines, but also to identify geological hazards, map forests and aquatic lands, determine where tsunamis have hit coastlines to aid in finding the best evacuation routes. It even guide future responses to climate change.
Washington is one of eight states to be developing a statewide lidar plan under the assistance of the National States Geographic Information Council. Once in place, the plan will be available to other states and will help with the establishment of best practices nationally. Well over 30 state, federal, local and tribal governments are currently involved in the process. The statewide strategy, expected to be complete in February, is aimed to guarantee a broad spectrum of participation among government and a common means of sharing both the high-resolution data lidar produces and the costs of gathering it.
Data sharing is especially important when it comes to lidar, says State GIS Coordinator Joanne Markert in the Office of the Chief Information Officer, who is helping with the coordination of the statewide plan as well as serving as co-coordinator of GIS Day.
Toe Jam Hill Fault (Washington Department of Natural Resources)
“One local government might use it for determining building heights. The U.S. Forest Service uses it for fire management and forest health, while F.E.M.A. uses it for emergency management planning. Tribes may use it for locating historical stream channels that could be used for salmon recovery,” Markert said. She and Abigail Gleason with the state Department of Natural Resources will co-present on the lidar plan.
Lidar relies on aircraft loaded with highly specialized equipment to make repeated passes over land and water. The data then must be meticulously compiled and plotted in any number of ways depending on how it will be used.
Lidar achieved global attention in recent years when the technology was deployed by the National Geographic Society to discover a long-lost civilization in a rain forest in the Honduras and a vast Mayan “megalopolis” hidden for centuries deep below a vast jungle in Guatemala.
Washington’s Department of Natural Resources (DNR) is the biggest user of lidar technology in the state. In 2015 DNR received a $4.5 million appropriation to collect lidar data across western Washington to identify geological hazards such as landslides and better identify flood risks.
Joe Smillie with DNR said the technology is especially useful in areas of the state’s west side that are covered with heavy vegetation and big timber as the lidar lasers can peer right through it. “We can see where the old landslides are, where land has moved and how glaciers have carved through valleys,” he said.
DNR is leading a county-by-county inventory using lidar to locate critical landslide hazard areas. Pierce County was completed last year. The agency will move on to Skamania County along the Columbia Gorge and King County later this year. After reviewing the lidar data, DNR sends geologists to the suspected landslide areas for additional verification and mapping work.
Sauk River as seen with aeriel photography and with lidar technology (Washington DNR image)
Washington tribes have been at the forefront of using lidar technology for years, according to the Northwest Indian Fisheries Commission.
For instance, the Puyallup and Muckleshoot tribes are using lidar-based maps to track the effectiveness of a salmon habitat restoration project along the Greenwater River earlier this decade. The Stillaguamish and Tulalip Tribes have partnered with DNR and three private timber companies to map forestlands in the Stillaguamish and Skykomish basins.
The Squaxin Island tribe is using lidar mapping models of Squaxin Island and Oakland Bay to help predict how sea level rise will impact their fishing rights and other natural and cultural resources. The Sauk-Suiattle Tribe is monitoring the amount of sediment moving through the watershed as glaciers recede with the aid of lidar.
Another potential use is in agriculture, where lidar-based calculations for slope and direction of croplands can help determine crop yield, drainage efficiency and fertilizer placement. It could also be used for orchard management.
The potential for lidar technology is just beginning to be realized, especially in Washington, Markert said.
“We are unique in the country. For one we’re on the west coast. We are large, we have a lot of coastline and shoreline areas, and we had already been collecting lidar already,” she said. “We want to do it more and do it better.”
The GIS Day event in Olympia kicks off with keynote speaker Josh Greenberg, who provides GIS analysis and remote sensing activities for the Skagit County GIS Department. It is one of many events around the nation in observance of GIS Day.
The Squaxin Island Tribe is using 3-dimensional models of Squaxin Island and Oakland Bay to predict how sea level rise will impact their treaty-protected fishing rights and other natural & cultural resources. (Northwest Indian Fisheries Commission).
Lidar imagery shows slides along the Cedar River (Washington DNR)