County Partners with State on Valuable Lidar Data

Data will help mitigate flood risk and aid in damage assessments.

by Jim McKay / March 9, 2018

Midland County, Mich., which was overwhelmed by flooding last year, will benefit from an agreement with the state to get access to new flood data collected last fall with lidar (light detection and ranging).

The data will help mitigate future flooding and also with recovery efforts. It will be shared by emergency management, the drain commission and the road commission, and the cost to the county is less than $5,000.

“There’s a federal push for elevation data across the country,” said county IT/GIS Director Chris Cantrell. “The state of Michigan partnered with the feds and a third-party vendor did the lidar.”

The lidar imaging will allow for GIS mapping that the county didn’t have before. “Those capabilities are huge for emergency management when you’re planning for emergencies and responding to them, especially when you’re going through damage assessments,” said Emergency Management Director Jenifier Boyer.

She said having the capability to map damages and severity of damages in certain areas of the community after flooding is huge. “Especially through the declaration process, but also in the city where they had sewer backups and whatnot.”

A downpour of more than 8 inches of rain last summer caused flash flooding that led to 16 road closures and millions of dollars in road damage.

Cantrell said the data will especially be useful for mitigation purposes. “Because we’ll be able to identify where the water will be at different flood stages and we can preplan on road closures and residential and commercial impacts. {We can] identify those areas that need to be closed and communicate it to the public.”

Lidar is captured with an airplane, which has an instrument on it that shoots a laser pulse down to the ground and measures the return back to the system on the plane. That measurement yields the elevation of the ground or whatever it was bouncing off, such as a treetop or building.

There are different Quality Levels (QL) of lidar, from one through four. Midland’s data is rated a QL2, which is the federal standard and very accurate.