On wide rivers it is not generally a requirement to protect across the full width of the bed of the river. It is normally only required to protect the bed for a distance of 1.5 to 2 times the anticipated scour depth to protect against under sour at the toe of the revetment (See Scour Protection Apron below)

Gabion mattress is a good material for river bank protection.The mattress units should be orientated correctly with the diaphragms parallel to the flow, otherwise stone migration down the slope can occur.

Where the river is navigable and the revetment is subject to wave wash, it is advisable to have an additional diaphragm down the centre of the unit. This gives a maximum cell size of 1m x 1m or 1m x 0.5 dependant on the slope to prevent movement of the stone infill across the unit.

For slopes of up to 1 in 1.75, the cross diaphragm spacing should be no greater than 1m and for slopes of 1 in 1.75 to 1 in 1, the cross diaphragm spacing should be no greater than 0.5m .