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Wednesday 29 March 2017

Environment experts from Southampton Solent University have been using Unmanned Aerial Vehicles (UAVs) to provide the National Trust (NT) with information on the erosion and deposition of the environmentally sensitive area they manage at East Head near West Wittering.

East Head is a significantly dynamic coastal feature at the western side of the mouth to Chichester Harbour. It has a range of habitats - from sandy and shingle beaches through to salt marsh – that support a wide range of flora, as well as providing winter nesting areas for a variety of birds.

Popular with visitors, the National Trust has to manage the competing pressures of public access and supporting the area’s status as a Site of Specific Scientific Interest (SSSI).

“As part of an Adaptive Management strategy for coastal defence it is important to have up to date and regular data on changes to the landscape,” says Dr Paul Wright, Head of Environment and Geography studies at Solent.

Using the Sensefly eBee UAV with an onboard camera, the team from Solent University have been able to collect over 400 images in just three hours, as opposed to the weeks it would take to get data of similar accuracy and detail using traditional tools and techniques.

The final orthomosaic - 400 images matched and stitched together like a big jigsaw!

Initial data collected shows that the main point of access to the site - The Hinge, in the very south - is susceptible to overwashing at higher tides; saltmarsh habitats on the eastern side of the site show rill erosion; and there are many desire lines (well-trodden paths created by visitors to the site).

“This survey allows the area’s National Trust’s Countryside team to decide upon their strategy for boardwalk replacement and path management,” says Paul. “Further processing of the data will give us a 3D model that can be used to create video flythroughs and, more importantly, comparative 3D models that will show not just loss/gain of area, but also of volume. This might help in planning any future work needed to conserve the area,” he continued.

Only trained drone pilots, with a license from the National Trust, are allowed to fly UAVs at East Head. Lisa Trownson, Area Ranger at East Head explains the value of making the most of new technology to commission regular surveys:

“Working with Southampton Solent University to be able to get such detailed survey data is amazing.  East Head is such a dynamic environment that it is often difficult to be able to explain the changes we see on a daily basis in such detail.  Now, with this technology and the analysis being done by experts, we’ll be able to show and explain the sand and shingle movement along with vegetation change to a wider audience. Importantly, we can also make detailed plans to manage these changing habitats in the best possible way for nature conservation, access and coastal change. We are glad to be able to share this with our partners on the East Head Coastal Issues Advisory Group, which includes the Environment Agency, Natural England, Chichester Harbour Conservancy, West Wittering Estate, Chichester District Council, West Wittering Parish Council, FG Woodger Trust and Cakeham Manor Estate.”

UAVs are beginning to play a big part in the collection of geographic and environmental information.

“We believe that this is going to be the go-to technique for surveyors, whether they are doing environmental work, construction site surveys, archaeological enquiry, or agronomy,” says Paul, “Sensors are being developed all the time, and it is great to be ahead of the game here at Solent.”