Arial laser surveying helps spot hazards at development sites

Arial laser surveying technology is helping pinpoint hazards at UK development sites.

Card Geotechnics (CGL) is applying aerial survey data from Bluesky as part of its investigation stage on proposed developments across the UK.

The geotechnical and consultancy agency prepares detailed reports for its clients on sites that range from residential developments to investigations for loverhead powerlines.

High-resolution aerial photography, specialist imagery and LiDAR (light detection and ranging) terrain maps from Bluesky are helping to identify areas of high geological hazards and associated risks.

These include issues such as sinkholes in chalk and other soluble rocks, saturated soft ground and peat deposits presenting compression hazards and areas with slope instability and landslides. 

The Bluesky data enables CGL to provide an accurate first-level expert interpretive scan of a site to assess and target more intrusive surveys for additional investigation and detailed design, saving time and money within the development process.

“The UK has many diverse landscapes with a wide spectrum of geological hazards, each of which can present challenges for development,” said David Giles, technical director at CGL. 

“Using geospatial data from Bluesky we have developed a digital imagery consultancy provision to offer the visualisation, analysis and interpretation of data for site investigations. This provides our clients with substantial cost and time savings.”

The Bluesky data used by CGL includes traditional aerial photographs which, when combined with the simultaneously captured near infrared wavelength data, can be used to produce colour infrared (CIR) images. 

CIR photography is a useful way of assessing the health of vegetation as healthy plants reflect more of the NIR wavelength and therefore appear brighter in the image. 

It can also be used as a tool to evaluate water quality as water absorbs the NIR wavelength whilst sediment and suspended particle reflect it. 

CGL is also using Bluesky’s LiDAR data, which is processed to produce both Digital Surface Models (DSM) that include vegetation cover and Digital Terrain Models (DTM), often referred to as bare earth models. 

LiDAR is extremely accurate allowing for various aspects of site assessment including flood hazard, geomorphological assessment and geological hazard identification.

“LiDAR models provide a highly accurate yet low-cost first development site scan which can identify construction and development risks at an early stage in the investment process,” added Dr Giles. 

“Ground-related issues can be interpreted from the imagery, delineating hazards that may not be possible to see or detect at the ground surface.”

Ralph Coleman, chief commercial officer at Bluesky, added: “We are continually seeing the cost and time savings that accurate geospatial data offers customers across a range of industry sectors and applications. 

“With a full national coverage of aerial imagery, Bluesky is well-placed to support the delivery of investigation projects like these.”