Culverts are crossing structures in running waters and allow the passage of water. They may be pipes that are laid under a road, allowing the flume to cross.
The culvert may be flowed through partially or in full, depending on the discharge occurring. A partially filled culvert with free surface is treated in the same way as an open channel, while a full flow through culvert corresponds to a pipe flow. By contrast, a full flow through culvert and a culvert in which the inlet is completely submerged are classed as control structures. These result in a limiting of the discharge. There may also be a combination of these two states, so that the culvert is in part fully flowed through and in part partially filled.
The culvert HM 161.45 contains two different cross-sections with the same cross-sectional area. The transparent material allows to observe closely the flow and occuring hydraulic jumps in the culvert. The culvert is fixed in the experimental flume using a clamping device.