Based on kindly provided information by the Scottish Natural Heritage

General description

Sand bags of various sizes and lengths can be used to form temporary reefs, breakwaters, groynes, headlands or revetments on sand beaches. Sturdy geotextile bags are filled in-situ with local beach sand and therefore have a relatively low cost.


Sand bag structures can be placed without the need for costly equipment or skilled labour. They can be used to form any form of shoreline structure but will have a short life expectancy due to lack of resistance to physical damage (wave borne debris impacts or vandalism) and the effects of UV sunlight. They are potentially most useful as a buried revetment under the dune face, where they will form a final line of protection after the overlaying sand has been eroded by storm waves. An alternative use is to form temporary headlands (Summary 9) to protect backshore assets while other, longer term, options are planned and implemented.


Bags should be filled and closed according to manufacturer’s recommendations. Care is required throughout to avoid selection should be governed by the anticipated methods of filling and placing on site. Labour intensive operations will limit bags to about 50kg and will only be appropriate for small schemes in low wave energy conditions. Large schemes will require filling and lifting equipment. A practical bag size limit is about 3m x 1.5m x 0.5m, containing about 3 tonnes of sand. Long tubes have been used in the past, but these are more likely to fail, as a single tear will affect the whole tube.

Damage to sand bag structures will be most intense at the alongshore extremes due to displacement by wave action, local scouring of beach levels and vandalism/public pressure. The ends of exposed structures should be feathered smoothly back into the dune face with the last 5m-10m of bags buried by several metres to allow for some future erosion. Maintenance attention should be focused on these potential problem areas.

Costs depend mainly on labour, structure dimensions and the need to bury the sandbags. Small schemes can be undertaken with volunteer labour with a minimum of lifting equipment, while larger schemes will require contractors with heavy lifting, pumping and earth moving plant. Costs of up to £100,000/km can be expected, with an anticipated scheme life of no more than 5 years.


Exposed sand bags are unsightly and easily damaged. As structures are effectively impermeable they will not absorb wave energy, and may cause local beach scour to accelerate. Damaged bags will release the fill material back onto the beach, but the bags will remain as unsightly debris along the shoreline. Assuming that the fill material is taken locally or is similar to the beach material then losses will be harmless.

As with all fixed defences the sand bags will interfere with the natural dynamic interchange of material between beach and dune. They will also influence the longshore transfer of sand, modify dune habitats, disrupt the natural landform and potentially result in localised dune face scour at their terminal ends.

Best practice and environmental opportunities

Buried sand bags can form a useful and low cost final line of defence in areas subject to mild, seasonal erosion. They are also useful for temporary (less than 5 years) headland protection while other options are considered, planned and implemented, but they should be superseded by a longer term solution. They have no environmental benefits except that they are temporary structures, easily removed with no significant long term impacts on the physical or natural environment.