SC050071 - Dunwich Coastal Defence Demonstration Project

Theme:Sustainable Asset Management
Project status:Completed
Start date:01/05/2006
End date:01/05/2013
  • coastal zone management,
  • Flood Defence,
  • adaptive capacity,
  • Erosion,
  • Climate Change,
  • Sustainable Development,
  • geomorphology
  • Terry Oakes Associates


Following the completion of the works in March 2007, monitoring was undertaken for five years to investigate the hydraulic performance and the condition of the various elements. The monitoring regime consisted of a series of beach cross-sections, aerial photographs and visual inspections. The project showed that the use of geomembranes and local beach material can provide a low-cost option for constructing structures intended to stabilise eroding beaches. The monitoring data indicate that the structures may have been in place during a period of relative calm when the beach has been accreting naturally. There was no detectable evidence that the structures were having a major impact of the condition of the SSSI or interrupting shoreline processes. As the humps have not yet experienced long periods of pressure from the weather and sea conditions, the project team recommended that they remain in place to allow continued monitoring and a judgement on the longer term impacts and effectiveness. The team also noted the need for careful selection of the plant used to construct schemes of this type and the need for further work on how best to handle and position the geotextile without jeopardising the design shape of the ‘geo-humps’. The results of this demonstration project have provided the Environment Agency, local authorities and coastal defence practitioners with valuable and real life information about the application of a new, innovative and low-cost technique for beach stabilisation. If the approach trialled here should prove effective in the long term, it may have potential for replication elsewhere in the UK.