2.3.7 Hydraulic Drop
The converse of the hydraulic jump, the hydraulic drop, can also occur due to an abrupt change in channel slope or cross-section. It can frequently occur near the entrance to a culvert flowing under inlet control. An explanation of culverts flowing under inlet control is given in Section 3.8.3 – Culverts Inlet Control.
Source: Chow (cited in DTMR 2010).