Lake ice ties age-old traditions to land during cold months in Canada, creating a cultural roadmap for recreation that utilizes the country’s frozen lakes. In all, there are more than 30,000 lakes in Canada. First Nations, the indigenous peoples of Canada who lived below the Arctic Circle, knew the value of these lakes more than anyone.
Lake ice records, kept over hundreds of years by First Nations, support long-held evidence that frozen lakes were a causeway for travel and trade between communities.
By keeping track of the seasonal thaw and freeze, indigenous groups could predict when it was safe to use frozen lakes as passage to local islands. But what they didn’t predict was climate change.
With water temperatures rising at a rapid pace, Canada’s lake ice is becoming more infrequent, or disappearing altogether during winter seasons. Not only will this upset the ecological balance of Canada’s various fresh water sources, it will take regional traditions with it, too.
Published in the Nature science journal, a 2019 report titled “Widespread loss of lake ice around the Northern Hemisphere in a warming world” warns: “Warming winters have reduced the duration and quality of ice roads, limiting access to remote communities. In addition, the quality and duration of winter recreational activities is declining with warming winters.”
But there is more at risk from disappearing lake ice than recreation, explains scientist Paul M. Cooley, Ph.D., founder and president of NextGen Environmental Research Inc. in Winnipeg, Canada. The presence of seasonal ice acts as a canary in a coal mine for monitoring the onset of climate change. As populations grow, so do the risks for people who use the waterways. “This is a new environment for everyone,” Cooley explains. “So even for people who are familiar with lake ice, we don’t have a history of the changes that are expected to come due to climate warming.”
This year, Cooley and the NextGen team will unveil the world’s first RADAR satellite based Lake Ice Hazard Advisory Service, packaged in a mobile app called “Ice Time.”
Over three winters and 84 lakes, the NextGen team utilized a mix of onsite data, unmanned aerial vehicle (UAV) photogrammetric images and synthetic aperture radar (SAR) satellite data to measure ice cover. Funded by the Canadian Space Agency, NextGen’s research will help provide regional residents and recreational visitors safe passage through the lake ice and help manage the onset of climate change.
“What we are doing is taking the research, developing what we’ve done with mapping and monitoring ice and putting it in the hands of people,” Cooley says about the development of Ice Time, which will be available in time for winter. “So even for indigenous communities, having access to technology like this will help them because it allows us to track and monitor the ice conditions.”
Surveying In Dangerous Conditions
Paul M. Cooley, Ph.D., isn’t a professional surveyor, per se. “I’m actually a scientist,” he clarifies. “I’ve done a lot of surveying to support science. It’s something I’ve learned along the way as opposed to something that I had dedicated study towards. But my surveying is always in support of the science.”
To map Canada’s regional lake ice, the use of a drone — or an unmanned aerial vehicle (UAV) — was an essential survey tool, says Cooley. While the NextGen team was safe on solid ground, a UAV collected photogrammetric images of lake ice from above, over areas too hazardous to survey by foot.
Considering the region’s rough winter air, NextGen chose senseFly’s eBee Plus for the job, a medium-sized, fixed-wing mapping drone that can map wider areas and is more aerodynamic when compared to copter drones. “When you get down to working in environments like winter conditions, and the requirements to map relatively large areas from a drone perspective, the list gets quite short real quick,” says Cooley about why he chose the eBee Plus model. “We’ve witnessed incomparable results from using drone technology. With senseFly’s eBee Plus, we were able to capture data from much larger regions and identify key areas for ice validation, even during challenging conditions. We were confident that the senseFly eBee Plus would be reliable enough for us to fly over the lake at a safe distance from the hazardous ridges — even once the ice had begun to decay and move, and we had to work from shore.”
When there are hazards on the ground, UAVs give surveyors an aerial advantage. As drone technology continues to improve, there are drones designed to fit nearly every working condition.
The co-founder of Swiss company Flyability, Adrien Briod, Ph.D., developed and patented novel approaches for the safe navigation of flying robots in cluttered environments while completing his doctorate at École Polytechnique Fédérale de Lausanne (EPFL). Briod’s interest in using robotic methods to enter hazardous and confined spaces increased after the Fukushima nuclear disaster in 2011. This led to the development of the Elios drone, equipped with a video camera, lights and a protective cage enclosing the entire unit. The collision-resistant system is designed specifically for indoor inspections.
Instead of utilizing LiDAR or SLAM technology to orient itself in a GNSS-deprived environment, the Elios relies on the operator, from outside the structure, to safely navigate while watching a live stream transmitted by the drone. After data are collected, photogrammetric software, such as Pix4D, creates a 3D model from the overlapping images and provides meaning and context. Operators are trained to plan their inspection and organize the data in a systematic manner, which enables the inspector to precisely locate a specified data point within the asset. Furthermore, the 3D models allow for advanced analytics of the data, such as performing measurements of defects or volumetry.
“Since the model itself is a patchwork of pictures extracted from a video, it is necessary to have one known distance within a model to scale the measurements,” explains Alexandre Meldem, vice president of sales, Flyability. “In a sewer, for example, the distance between the center of both manholes is known, which enables the inspector to accurately scale the 3D model and to draw accurate measurements from it.”
To protect life and property and avoid interruptions in service, critical infrastructure is subjected to rigorous inspections. Depending on the type of structure, there are governmental and industry organizations that set standards and recommend best practices for conducting periodic reviews. To perform as well as a person, the resolution of the data captured by the camera is comparable to what one would get with a human eye at “arm’s length” from the target. The Elios 2 collects images with a Ground Sampling Distance (GSD) down to 0.18 mm/px (0.007 in/px) at a 30 cm (11.8 in) distance.
In May 2019, the American Petroleum Institute (API) published a “Guide for Developing a UAS Program in the Oil and Natural Gas Industry.” With safety as its number one priority, the organization continues to study how drones can be integrated into very complex processes and how they might be used for inspections. It can take years to write new standards, but with increasing pressure to cut costs as oil prices fall, drones are getting more attention as a cost effective way to safely maintain industrial facilities.
During bathymetric surveys, drones also prove to be a cost effective way to access water and underwater data.
Not to be confused with hydrography, “bathymetry” refers to the ocean’s depth relative to sea level. However, over the years, bathymetry is widely used to refer to any type of underwater topographic survey, including rivers, streams and lakes. In some cases, dense seaweed can prevent the lowering of echo sounders in water, or complicated water access can rule out unmanned surface vehicles (USVs) entirely. In other cases, you may need to conduct multiple surveys of small ponds, lakes or trenches. For such survey projects, drones can be outfitted with an echo sounder to move across a water’s surface.
“It is better to use a drone with an echo sounder for mapping, measuring and inspecting tasks and environmental monitoring if you are conducting bathymetric surveys of tailings dams and ponds,” explains Alexey Dobrovolskiy, CTO at SPH Engineering, which provides software and integration services for unmanned systems. “Drones are also used in bathymetric surveys of ponds in open pits, mapping of sediments of oxidation and tailing ponds, and mapping water depths and sediments before dredging and cleaning of ponds, lakes, rivers, and canals.”
Whether surveying above or below ice, Dobrovolskiy explains that the most important thing to know is the types of data files that will be needed to provide survey results. Depending on the technology needed for the job, drone models typically can adjust.
“For (bathymetric) operations, we recommend using standard commercially available drones like DJI M600 Pro, M210 or the new M300,” says Dobrovolskiy. “You can also use drones based on the open source Pixhawk autopilot. If you choose to use standard popular drones, the echo sounder will be just one more sensor for your multi-purpose bird. You can use it for photogrammetry, LIDAR, magnetometer and other missions.”
In combining satellite and drone technology, Cooley says he was able to gather low altitude data on ice changes more effectively than using terrestrial techniques. In total, NextGen carried 14 surveys to gain a comprehensive overview of the terrain and create detailed digital elevation models.
With approval from Transport Canada, the eBee Plus was deployed within the visual line of sight (VLOS), with the aid of a visual observer. To streamline processes and data analysis, NextGen utilized senseFly’s eMotion flight management software prior to each flight to assess project feasibility, plan flight routes and load elevation data in advance.
Each flight collected hundreds that were mosaiced together at an average resolution of 3.2cm per pixel. Images were processed using Pix4DMapper software to create highly detailed digital surface models and thermal imaging that were subsequently used to draw comparisons between the location and size of ice ridges across the lake from week to week.
The photogrammetry software enabled the team to process data in less than a day before the satellite overpass, which is typically a challenging feat for this kind of large-scale project.
On Lake Winnipeg, the eBee Plus was deployed to cover an area spanning approximately 1km by 0.8km across two sites, together with data from 14 satellite overpasses. From late February to early May 2018, the team carried out a full topographic survey every week, using the digital surface models to help complement the data provided by the satellite imagery. The drone was flown the night before the satellite overhead would pass, allowing an intricate bird’s-eye view of the ice features, and enabling a better understanding prior to collecting larger scale data with the satellite.
High-resolution images captured by senseFly’s eBee Plus in low earth orbit enabled the creation of orthomosaics maps, which clearly showed the location of ice hazards, including rough ice. Expanding on the insights reported by satellites, the data captured by the eBee Plus also showed that it can be utilized to determine safe lake ice travel routes.
The Elevation of Survey Tools
When the Ice Time mobile app is unveiled to the public, users will be able to access information on ice hazards in real time.
“It also allows users to input their own ice hazards on a map or look at the radar imagery uploaded by the NextGen team that shows ice hazard features,” Cooley explains. It's something that has never been done on lake ice before and is exactly the type of project Cooley created NextGen to take on.
“Integrating technologies is one of the premises that the company is built on,” he says. “In the last 5 to 8 years, we’ve seen the maturation of the internet; we’re seeing the maturation of technologies like satellite technology and surveying technology. The tools available are precise enough where someone who is a non-specialist in it can easily access that information and therefore you can integrate multiple things.”
If warming climates continue at today’s pace, ice safety will become a critical issue for Canada. Melting ice can result in leads and cracks as open water becomes exposed, while pressure ridges can extend 3 m above the surface and run along it for more than 100 km on larger lakes. In winter, these pressure ridges are barriers to travel and a collision risk, while in spring the axis of the ridge is typically where the first open water occurs. During cold periods, cracks can also create open water when horizontal ice sheets shrink. Thin ice then forms in the crack overnight and become covered in snow, creating an unseen hazard the following day.
Studies have shown that the next few years could lead to a reduction of the lake ice mass, increasing the risks for those travelling on the ice roads — from rough ice collision to immersion of property and people.
“And so we are seeing people making the same mistakes because you can’t base your travel on the ice on a calendar like you used to be able to,” says Cooley. “So we need technology to help us monitor that. And whether you’re an angler going ice fishing or you’re an indigenous person in a remote location, using technology like this, and we are using synthetic aperture radar imaging, is important to everybody to help us adapt through climate change.”
One of the challenges of the project is helping people relate to what they are seeing on a map versus what they can see through their own eyes. In the coming years, the NextGen team will continue to work with the Canadian Space Agency to further their understanding of challenging ice conditions with the use of technological advances, such as drones.
“And surveying is going to be one of the underlying professions in helping us understand satellite data,” says Cooley. “We can get these images relatively easily but you need technology like drones to help us understand what the satellites are seeing. So we are taking observations at the human level, when you are standing on the ice, extending that to local areas using drones and extending that again using satellites for this.”
He adds, “What our company is doing is integrating remote sensing platforms, surveying platforms and now software application development so we can have environmental applications in the hands of users. So it’s really technology integration and that’s what I see the overall theme of science and technology is doing now.”
For more information about Ice Time, visit nextgenenvironment.ca.