With a laser focus, LIDAR collaboration provides data, savings

A consortium of 28 cities and service providers came together to fund a LIDAR flight generating new, detailed mapping of the greater Portland region.

The LIDAR flights covered 976 square miles offering the most comprehensive data set ever collected in the area. Metro’s Data Research Center says the $800,000 project would have cost nearly $6 million if each of the 28 participants had ordered their flights individually.

LIDAR, or Light Detection and Ranging, uses laser point measurement to produce a topographical image of an area. The data shows both where the ground is and what’s on top of the ground – offering insight into vegetation height and density as well as building height and floor-to-area ratio.

In producing these detailed images, scientists are able to evaluate land conditions and do precise land assessments. Assessing risks of erosion and landslides is made more effective and efficient with the detailed data achieved with LIDAR.

Slopes, ground conditions, changes over time, all help natural area planners and land use planners make informed decisions from trail planning to development, said Tommy Albo, Metro natural areas GIS coordinator.

In addition to general topographical uses, the data can be customized to provide information on specific items collected within it. By setting parameters the data can evaluate specifics such as vegetation height mapping. Maps can be created that use color to identify vegetation height which allow scientists to distinguish areas of invasive species, such as blackberries and hawthorn, from native trees, and target treatment areas. Metro natural areas scientists used this type of LIDAR vegetation height mapping in recent restoration work at Scouter Mountain.

“For restoration it’s so helpful,” said Kate Holleran, a Metro natural areas scientist. “You might be able to get this information by walking back and forth on a property, but we’re talking over about 25 acres.”

“It’s a great way of telling a story,” she said. “Someone with no technical knowledge would be able to see the colors and know how much work there was to do.”

Metro natural areas scientists also use the data in the land acquisition process, Holleran said. LIDAR mapping can help in trying to understand previous land-use – old building material, old roads or slides – things you might miss on a larger property.

Clean Water Services, a Washington County sewage treatment agency that is one of the project’s partners, is using the new LIDAR data to more effectively monitor their water temperature management strategy in a way that would not otherwise be possible.

Clean Water Services has taken a natural approach to reducing the temperature of the Tualatin River, which receives 60 million gallons of treated wastewater each day. The company has planted dense native vegetation along stream banks to shade the environment, creating a solar offset to the heat increase caused by the treatment facilities.

The new LIDAR data gathered provides the company with a way to evaluate the growth and loss of that streamside vegetation and the changes in solar offset over time. Comparing the new LIDAR data to smaller flights from 2008 and 2012 they can assess how much additional coverage has taken shape, as well as where they’ve experienced vegetation loss, most commonly found near new beaver dams.

“This project won’t just give us shade credit but provides enhancements to salmon habitats or runoff or wildlife connectivity throughout the watershed,” said Brian Shepard, a specialist with Clean Water Services.

Original feature appeared at Metro News.
Photo credit: Metro.