Enabling rapid response to flood defence breach

The ARC-Boat is an innovative remote controlled boat that is used to collect river, reservoir and estuarine data such as flow rates, depth and suspended sediment concentrations. Produced by HR Wallingford, the ARC-Boat has delivered real operational benefits for the Environment Agency in England, and helped them to quickly respond to breaches in flood defences during the storms of winter 2013/14.

HR Wallingford developed the ARC-Boat in response to a request from the Environment Agency. The two organisations worked in partnership to develop the boat, ensuring that it met the needs of end users. The ARC-Boat’s V-shaped hull was designed by naval architects to give optimal manoeuvrability and minimal air entrainment, ensuring that the data collected is of the highest quality. It can be equipped with GPS, and features a ‘moon-pool’, a sealed instrument holder with an open base, that can be adapted to carry a variety of instrumentation including Acoustic Doppler Current Profilers (ADCPs), sub-bottom profilers and echo sounders. The boat also has the potential to carry multi-parameter probe systems, further broadening its potential application.

At Seal Sands in Teesside, the ARC-Boat was used to survey an 80 m breach in a flood defence embankment
[© Environment Agency]

The operational boat is just less than 2 metres in length, but the bow can be quickly detached from the main hull to reduce the length to 1.2 m; and as a result it will fit into an average sized car, eliminating the need for trailers or specialist vehicles. Grab handles allow it to be safely deployed from the most difficult locations and the independently controlled propellers and twin rudders deliver excellent manoeuvrability, even in the roughest conditions. The boat employs an industry standard remote control with a range of up to 200m and Bluetooth communications for data transmission to an onshore laptop.

Launched in 2012, the boat is now in use internationally, and users include the regulatory bodies such as the Water Survey of Canada, and the National Institute of Water and Atmospheric Research (NIWA) in New Zealand.

In the UK, as the ARC-Boats prove their value in operation, the Environment Agency’s fleet continues to grow, and they now have at least one boat in use by every area office in England (and in Wales by Natural Resources Wales).

Data collected using the ARC-Boat was used to produce a 3D image showing the extent of a flood embankment breach near Boston in Lincolnshire [© Environment Agency] - Click image to view large image

Environment Agency staff deployed ARC-Boats in December 2013 when storms caused significant damage to a number of coastal structures. Among these were flood defence embankments in Teesside and Lincolnshire. The Environment Agency used the boats to assess the extent of the damage to these structures, and to rapidly provide data that could inform their plans for remedial action.

In Teesside, severe weather and a storm surge resulted in the highest tide recorded in 150 years. This caused significant damage to a flood embankment at Seal Sands near Billingham, scouring a hole in the structure that was some 70-80 metres across. The breach allowed large volumes of sea water into a nature reserve listed as a biological Site of Special Scientific Interest (SSSI) and threatened local industry and residents.

As the full extent of the damage to the embankment was not visible, even at low tide, an ARC-Boat fitted with an ADCP was used overnight to survey the area in around an hour at high tide. The data collected was used by staff on site to produce a 3D map of the hole. This enabled the Environment Agency to act swiftly and effectively to repair the damage. Initially, Chinook helicopters were enlisted to bring in construction materials. Later a temporary road was built to provide access by land.

“In the past, this type of survey would have been conducted by a team from a boat using instrumentation mounted on poles,” explains Nick Everard, Technical Adviser in the Environment Agency’s Hydrometry & Telemetry team. “In both Teesside and Lincolnshire the deployment of the ARC-Boat was a great success. It allowed us to carry out surveys very quickly and to collect high quality data that let us take swift action to protect these areas. Importantly, our staff could stay safely on land throughout.”

 

HR Wallingford Logo

For more information please contact Dr Keith Powell, Director, HR Wallingford (01491 835381; E-mail k.powell@hrwallingford
.com
).

 

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