Bluesky Airborne Lasers Assess Flood Risks

26 March 2009, 3:06pm

Highly accurate 3D digital maps, captured from aircraft mounted lasers, are being used to assess the risk of flooding at critical utility sites across the UK. The project, undertaken by Ambiental on behalf of one of the UK’s largest water companies, used LiDAR (Light Detection and Ranging) data supplied by aerial survey specialist Bluesky to help examine the likelihood, extent and depth of potential flooding as part of a review of flood defence measures at each of the five sites.

The Bluesky data is part of 3D terrain map, available online, that covers most of England and Wales including all major urban centres, coastal areas and flood plains.

Ambiental, a specialist environmental risk mapping and modelling consultancy, used a combination of existing datasets, models and gauged data in combination with their proprietary modelling and mapping techniques to assess and quantify each flood source in turn. Potential sources of flooding considered during the analysis included fluvial (river), tidal, surface water, sewer and groundwater. The high resolution LiDAR data, supplied by Bluesky, was used to map each risk in 3D to ascertain the spatial distribution of different flood depths. The results of these assessments were used for business planning purposes, specifically within cost-benefit analysis for flood defence measures at each site.

“The use of high-resolution, high-accuracy remotely-sensed data, such as the LiDAR data supplied by Bluesky, was critical to timely and cost effective completion of this project,” commented David Martin, Technical Manager at Ambiental Technical Solutions. “By utilising off-the-shelf data we were able to achieve considerable savings in terms of time and money over conventional ground-based surveying techniques for a project where time was very limited.”

In order to capture the highly accurate LiDAR (Light Detection and Ranging) data a survey aircraft equipped with a system of lasers is used. Lasers are beamed to the surface and the time taken for the beam to be bounced back to aircraft-mounted receivers is recorded. Using the known position of the aircraft (derived from on-board satellite positioning equipment), the time taken for the return of the laser beam and the known value of the speed of light, the distance between the aircraft and ground is calculated. Additional readings can also be taken to determine the height of buildings, vegetation and other surface structures.

Ambiental is a specialist environmental risk mapping and modelling consultancy founded in 1997 as a partnership of researchers at Cambridge University. The company has grown rapidly and now includes experts in the fields of flood modelling, risk management, insurance, rainfall simulation, climate change, geomorphology, computer programming, civil engineering, Geographical Information Systems (GIS) and applied mathematics. Ambiental offers a complete flood risk assessment service for property developers, architects, energy providers and loss adjustors and has completed projects in the UK, USA, mainland Europe and Asia.

www.bluesky-world.com
www.ambiental.co.uk
Contact Bluesky on +44 (0)1530 518 518

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