Putting Haliburton County on the LiDAR map
By Sue Tiffin
Published Sept. 19, 2017
LiDAR is coming to Haliburton County, one way or another.
The county was presented with a comprehensive look at the cost of LiDAR, or Light Detection and Ranging, a technology that uses a laser-based system to produce very detailed topographical images, by director of planning Charlsey White on Sept. 12.
LiDAR would be used to take height measurements from the ground and elevation above the sea level and water level for select lakes and rivers within Gull River and Burnt River watersheds, creating updated flood plain mapping. Consultants hired by the county would obtain the LiDAR mapping data, then process it, turning it into actual mapping and flood mitigation plans. The data would never expire.
“Specifically, the information would lead to new flood mapping as well as flood mitigation and preparation plans to help alleviate and/or reduce property damage, infrastructure damage, as well as provide information to each of the local municipalities for when you’re doing infrastructure upgrades in the near or distant future,” said White. “Some other information that I’ve obtained is the usefulness in having it turned into hydrologic studies, so we actually get the assessment of what the flows are from each lake, within each basin, how they move through the rivers and what the impact is, and what the impact is when we have, say, 10 mm of rain versus 70 mm of rain, plus snow melt, to actually come up with what that flood would look like in our area.”
After much research, and discussion with experts, White presented several options for the county to choose from in applying for funding through the National Disaster Mitigation Program (NDMP) funding application. Option A would see the LiDAR mapping done in two rounds, first for the Lower Gull at a cost of $531,820, and later in the Upper Gull and Burnt River, at a cost of $641,690 for a total cost of $1,173,510. Option B would see the LiDAR just done on the Gull at a cost of $1,050,140, and Option C would see it done for the Burnt River at a cost of $514,870. Option D offered LiDAR for both the Gull and Burnt watersheds for the total cost of $1,173,510. The NDMP funding could potentially cover half of the expenses of the project.
White recommended Option A, largely for reasons of cost. She noted that LiDAR doesn’t go through water, and so in this area, it would be best to fly the LiDAR starting in the fall of 2018 when water levels are low and leaves are off of trees.
“Once the data is collected it will need to be processed,” White told the Echo. “All of that will be completed for both watersheds under this round of funding if approved. What happens next is the surveying, engineering, hydrology, and other detailed work to create the model and mapping for each watershed. It is intensive work which, due to the project area, is not possible to be completed in the timeframe set out by this funding window. Therefore it was recommended that the Gull River Watershed from Hwy 118 south be completed.”
With LiDAR completed, White said the upper Gull River watershed and Burnt River watershed could be completed at a later date, with additional funding available at that time.
“I know it’s an awfully big chunk to bite off, but I think we’re kind of behind the eight ball,” said Liz Danielsen, deputy-mayor of Algonquin Highlands. “This should have been done … it would have been so helpful to have this information in place years ago. And I personally would like to see us go for the whole thing.”
Dysart et al Deputy-reeve Andrea Roberts asked what could be done with the information obtained in the LiDAR project.
“Once we take this data and convert it into a mapping product, what we can look at it is say, OK, we have X metres of snow currently on the ground, our temperature is going up to this temperature, we have 30 ml of rain coming and it can show you where that water’s going to come, so emergency management preparedness, local or county councils could have people move out of those areas, increase sand bags, co-ordinate emergency services, and the mapping could be used in future planning of those areas to know where those flooded areas actually are,” said White.
Minden Hills Reeve and Haliburton County Warden Brent Devolin said the mapping would also help in other areas, such as the management of dams.
“They’ll be able to run some of the ‘what ifs’ in developing and designing those,” he said. “It’s just a much, much more accurate tool for all kinds of purposes. In the end, I make this statement, it will be done eventually for the whole watershed.”
“How close are the TSW going to follow this when it comes to managing it?” asked Dysart et al Reeve Murray Fearrey, who said he appreciated the project.
“I think past actions are good predictors of future intentions,” said Devolin. “I would say they’ve already started to make some movement with some of this kind of data. They’re encouraging their bosses that this is necessary and required, for them with the TSW, for the MNRF to manage what they’re doing, for the municipalities – they know a more precise tool improves benefits.”
Council voted for Option A, and all agreed to have LiDAR mapping completed for the full watershed.
“Our absolute intention is to do it all, but we’ll compartmentalize it,” said Devolin.
The project would have to begin by March 31, 2019 and be completed by the end of March 31, 2020.