General Information 
Bastions can be used as temporary structures on civil engineering construction sites or as rapid deployment flood protection barriers in place of sandbags in certain circumstances.
When used for temporary works they should be properly engineered as gravity retaining walls. For temporary retaining structures a suitable drainage fill should be incorporated through the structure at regular intervals along the wall length to prevent build up of hydrostatic pressure. Bastions are not free draining like stone filled gabion structures.
For flood defence purposes bastions should be sand filled. It is also common practice for the front face to be additionally externally lined with an impermeable liner.