Wooden Revetments

Timber revetments can range from substantial, impermeable breastwork to temporary permeable upper beach wave barriers. The former is a final line of erosion protection, while the latter serves to partially dissipate wave energy before it reaches the shoreline

Woodern revetments have been widely used in the UK for coast protection where the costs or impacts of a seawall may have been unacceptable.

Construction flexibility allows timber revetments to serve various purposes. They can provide a partial barrier to wave energy when built as a permeable “fence” along the upper beach.

Alternatively they can form a final wave protection wall when built as an impermeable vertical breastwork along the dune face. Temporary structures can be built relatively cheaply of pressure treated softwood but more substantial structures are usually built of imported hardwood.

Concerns over the sustainability of hardwood sources have increased material costs considerably, making it unlikely that large scale timber defences will be used in the future. Timber is now only likely to be viable for smaller schemes in relatively low energy areas.

On an open beach exposed to large storm waves, hardwood structures will be abraded, giving a life expectancy of around 15-20 years. Within estuaries or on low energy beaches the timber may last 25-30 years before abrasion and wood boring invertebrates cause significant damage. Softwood structures are likely to have a life of only 5-10 years.

Happisburgh's (Norfolk), timber revetments, shown above, were constructed in 1959 as part of a series of protection measures put in place following the 1953 East Coast floods. They started failing in the 1980's, and by 1989 North Norfolk District Council (NNDC) identified the need for a major investment in new defences.