6 minute read
Use of drone technology for wildfire management purposes - By Rob Erasmus
By Rob Erasmus, Enviro Wildfire Consultancy
The use of technology for fire management is not new and progressive wildfire managers continue to seek methods of obtaining information that allow them to make sound decisions. The old saying that ‘information is power’ holds true and a simple example is the use of cell phone apps to obtain local weather forecasts to predict fire behaviour.
The use of technology is only effective if the equipment is used within its operating parameters and the information analysed and interpreted by suitably skilled personnel.
The use of drone or remotely piloted aircraft systems (RPAS) technology has become increasingly common in all spheres of integrated wildfire management, ranging from pre-burn veld assessments and firebreak inspections to fire spread monitoring and burn scar perimeter patrolling.
UsesThe use of drone technology can effectively be divided into three categories, namely pre-, active and post-fire periods.
Pre-fire use can generally be undertaken with a normal visual camera drone and there are plenty of makes and models to choose from. Tasks can include veld assessment ie fuel load density and arrangement, topography, general site overview, firebreak conditions, access roads and paths and the location of infrastructure requiring special attention.
During active fire operations (wildfires or prescribed burning), a thermal camera drone is of significant value as it is able to ‘see through the smoke’ and provide valuable information as to the location and extent of fires that are burning. In high fire risk areas this becomes really valuable as the smoky areas downwind of the fire can be monitored for spot fires or firecreep across the breaks.
Post-fire tasks include fire-scar mapping and patrolling of burn area perimeters for smouldering material that has the potential to start rekindled fires. The most efficient time to conduct smouldering ember patrols is just before sunrise when the surrounding ground is probably at its coolest, increasing the likelihood of hidden embers being detected. Bear in mind that some thermal camera drones are able to detect a smouldering item 10cm in size from 100m away. Very rocky habitats have the potential to shield embers from the cameras view. Once again the experience and skills of the drone pilot becomes of value in interpreting the information.
Recently a fire spread through the Onrus River and ignited the desiccated underground peat bed. Upon inspection with a thermal camera drone it was determined that the entire river bed was burning and it took 12 months of active fire management to eventually extinguish the fire.
Most drones with thermal cameras have as variation of three viewing modes. The visual mode makes use of the normal visual camera that usually has a high resolution capability and possibly a zoom option.
The infrared (IR) mode uses the thermal camera and the resolution can range from average to very good. In some cases the thermal view can also be zoomed.
The skills of the drone operator can maximise the value of this thermal information by managing the settings. A third viewing mode uses a combination of the visual and thermal cameras, overlaying visual camera data on the thermal image to provide a clearer definition of objects in the thermal view. In some drones this combined mode is the standard for the IR view.
LimitationsThe majority of drones can fly in winds that gust up to about 30km/h. Although not ideal due to increased battery power consumption, necessary flights can be undertaken. They can be flown in stronger winds when operating in sports mode but the risk is that the obstacle avoidance system is then disabled. Once again, understanding your drone and your flying environment will allow decisions to be made.
Another option of using the sports mode is when it is required to fly through smoke. The drones’ sensory system would regard the smoke as a barrier and start to hover.
When using a thermal camera drone, the ability of the pilot to set the camera parameters ie thermal window range, palate, temperature alarms, etc and interpret the thermal image becomes really important. Situations could result when an inexperienced pilot does not have the skills to manage the thermal data and blames the equipment for it being inadequate.
Raptors have learned that fires flush out insects and other small animals, providing easy meals. These large birds such as Yellowbilled Kites, are known to attack drones and in such cases it is suggested that the pilot rapidly ascend approximately 20m and return to the landing zone before the drone is lost due to a bird strike.
SafetyDue to the potential catastrophic implications of a drone striking an aircraft, no drones are to be operated within the fire arena without the express authorisation of the incident commander. The drone pilot should also be in radio contact with the Spotter pilot, alternatively the aerial resources, purely for safety purposes.
Drones should not be flown over public roads or at a height exceeding 150m (there are exceptions) and on or over property without the landowner or incident commander’s permission.
While drones can be flown while aerial resources are operating, this is an activity that needs to be extremely carefully coordinated.
Additional optionsSome drone models allow for a set of goggles to be connected (Wi-Fi or wired) to the flight controller providing the wearer with an ‘Imax’ type real-time camera view from the drone. Some models even allow the wearer to control the direction of the camera by simply moving their head sideways and up/down.
For experienced wearers, there is also the advanced option of them controlling the direction, not speed or ascending/ descending, of the drones’ travel.
A commonly used technique is to connect the controller to a large external screen, which provides a large group a real-time live view from the drone. Some drones can also be programmed to fly preplanned routes autonomously. This is extremely useful when repeated fire perimeter patrol flights need to be undertaken in remote areas.
ClosingIt could be difficult to dispute that drone technology, when used responsibly, has the potential to be a game-changer when it comes to integrated wildfire management.
For further information or interest, please contact Rob Erasmus at Enviro Wildfire Consultancy on Mobile: 083 411 3378 Email: enviro@absamail.co.za.
NOTE: Enviro makes use of the DJI Mini 3 Pro, Mavic 2 Pro, Mavic 2 Zoom, Mavic Enterprise Dual (thermal) and Mavic Enterprise Advanced (thermal) drones.
