Sandbags for flooding

In every emergency situation, being prepared is one of the best means possible in order to try and minimise the amount of damage inflicted on yourself, your family and property.

Sandbagging / creating a levee

Sandbags stacked to form a barrier against rising floodwaters are one of the most common emergency (flood-proofing) techniques used.

The bags used must be of suitable construction and have sand (brick or packing sand) or other fill placed in them to hold off water as long as possible.

Water exerts large amounts of pressure against the bags therefore (and if possible) a shallow trench should be dug to provide a footing. Other methods used to create an anchor for a small levee are to place the bags on or against specific features such as a ditch, open drain, raised roadbed or against a foundation wall.

When laying the sandbags it is a good idea to anchor sheet plastic underneath and place up across the front of the levee facing the floodwaters as this will assist in preventing seepage. (Refer to the diagram below)

Cross section diagram of a sand bag levee construstion.

Sandbags should never be totally filled with sand for two reasons:

  1. It allows them to 'overlap' one another, which locks them in place (as you would stack hay). In addition, the bags should be stacked at right angles to layers above and below, this is done so to provide greater stability.

  2. They will be too heavy to lift, particularly after the waters have subsided, because wet sandbags are heavier than dry ones.

Page last updated: Friday, 8 October 2021