The news that the University of Leeds will be developing drones that could make self-repairing cities a reality has highlighted the myriad of potential uses for drones in civil engineering.
Closer to home, drones, or unmanned aerial vehicles (UAVs) are already making life easier for engineers and public works professionals.
intouch spoke with Logan City Council surveyor Scott Grattan about how the council is using UAVs to inspect landfill.
intouch: Why did Logan City Council decide to investigate the possible use of drones?
Scott Grattan: Logan City Council is committed to ensuring we provide the best possible service for our residents. Part of this is a commitment to innovation and encouraging staff to investigate emerging technology and techniques. UAVs have been around for some time now and are becoming more cost effective, making them suitable for use for a wider variety of projects.
intouch: Are there any similar organisations utilising drones that you took note of?
Grattan: We are aware of other local councils also investigating the use of UAVs in their areas and private companies using them for projects such as pipeline mapping and stockpile surveys.
We can draw a pretty clear comparison to mining operations at places like our Browns Plains landfill site – just in reverse. A mine site needs to know how much spoil is coming out for their reporting and we need to quantify how much material is coming in.
Aerial photography has been a useful tool for many years for land management projects. Anyone who has ever used Google Maps can appreciate the wealth of information a picture can provide. Using a UAV is an efficient and effective way to have up-to-date information provided for project areas, with minimal ground resources. The usage of aerial photography isn’t limited to just government undertakings as many private companies, and indeed the public, can source that information for daily use.
intouch: What method did you use to determine how accurate drones could be?
Grattan: To ensure that we could reproduce the accuracy required for our environmental reporting, we made a direct comparison to field data captured by traditional surveying methods. We compared 3D surface models, produced by the two methods, within a Computer Aided Design (CAD) software package to create precise volumetric calculations. Results achieved with UAV information were found to be comparable and in line with expectations for reporting.
intouch: What were your findings?
Grattan: We found that as long as sufficient ground control was used that in open areas, the information provided by UAVs could meet and even exceed the accuracies previously achieved via field surveys. UAV accuracy is assisted by a much smaller point spacings assisting overall accuracy.
Simple point-to-point comparisons found field survey to have an advantage, but a UAV is able to produce significantly more points over the required area in a shorter timeframe.
This additional information (that identified greater detail in surface undulation, which otherwise may have fallen between field survey shots) allowed for accuracy in reporting.
intouch: What possible applications do you think drones could have in Logan City Council, and why?
Grattan: Logan City Council has already begun using UAVs for regular volumetric reporting at its Browns Plains landfill. It has the noted advantage of removing field staff from the active fill site and possible conflict with site machinery. The UAV floats safely overhead and the machinery operators can continue their work uninterrupted. A job that previously took the better part of a day can now also be completed in a few hours.
We have had similar success using a UAV with LiDAR (Light Detection And Ranging) instead of imagery at our previous quarry sites, to aid in their rehabilitation. The information was used to create accurate surface models of the sites, allowing for better future site use planning. Further use of UAVs on these sites could allow for accurate reporting in respect to long term planning.
We have also recently trialled their use for areas of environmental concerns, where remnant vegetation has been disturbed or soil has allegedly been introduced to inundation areas. A picture sometimes truly is worth a thousand words and being able to quickly and easily see and quantify affected areas is expected to be a useful tool.
intouch: Have you come across any limitations to the technology?
Grattan: As a developing technology, there are still some processes that are being improved. Environmental factors such as high wind or heavy rain can prevent a survey flight from occurring. Thick vegetation, such as lantana, can also prevent a UAV from accurately creating a ground model.
UAVs are treated as aircraft by CASA. Australia was the first country in the world to regulate remotely piloted aircraft. All the safety restrictions binding aircraft flight apply to UAVs. The community can be assured there is appropriate regulation and safety management when we use this emerging technology.
intouch: Where to from here? Will UAVs become a regular sight around Logan?
Grattan: Council is assessing its use of UAVs and other technology in regards to land survey works. Our team is briefing other areas of the organisation on progress and achievement with this technology. We will continue to evaluate potential beneficial uses for this emerging technology.
Intouch: There have been a number of concerns linked to drones, namely privacy. Is that something you have needed to work around?
Grattan: Our work with UAVs has predominantly been over properties we own and operate, such as the Browns Plains landfill and a quarry. Where the technology has been used over private properties, we have completed this work with owner consent or enforcement notices, if necessary.