Gabion weirs are widely used for river training, for the formation of reservoirs and for water diversion (for irrigation and for the supply of domestic water). Gabion weirs are classified in three principle types, according to the shape of their downstream face at the centre of the flow:

Vertical Weirs are the simplest type, often used for small structures, in particular if a series of weirs is employed to control a stream reach or in rivers carrying heavy bed loads. In order to ensure the best performance from the structure, the wire netting over the crest of the weir and also the surface of the upstream ramp (which may consist of an embankment resting against the ramp) must be fully protected and protection also given against scour at the toe of the foundation.

Stepped Weirs differ from vertical weirs only because the water flowing over the weir dissipates part of its energy at each step of the weir face. This structure is suitable only if the unit discharge is small, and no heavy bed load is carried by the river.

Sloped Weirs offer greater guarantees from the static and hydraulic points of view; their use is to be preferred for large weirs designed to train reaches of rivers having large discharges, light bed loads, and soils with a poor bearing capacity. With this type of weir it is advisable to protect the crest and the downstream face by means of concrete or, preferably, sand asphalt mastic.