The Controflow® orifice design is based on well-established flow rate performance characteristics using the standard orifice equation. The Controflow® orifice profile is recognised as delivering a standard 0.65 coefficient of discharge irrespective of orifice size.

The performance of Controflow® mimics the gradual response of natural drainage particuarly during short duration or low intensity rainfall. Full flow characteristics operate once the storage depth provides the designed ‘hydraulic head’.