Headwalls or wingwalls improve the flow of water into and out of conduits, provide anchoring support for the pipe and prevent dislodging under excessive pressures, control erosion and scour resulting from high water velocities and turbulences and to prevent adjacent soil from sloughing into the waterway opening. Headwalls are necessitated by limited space and poor soil conditions.
The inherent flexibility and porous nature of gabions address the design concerns of headwalls which must properly dissipate the energy of water flow, withstand or relieve soil and hydrostatic pressures, and in areas prone to such seasonal changes, withstand the effects of frost action acting upon the soil. preclude detrimental heave or lateral displacement resulting from frost action.
The outlets of pipes and lined channels are points of critical erosion potential. The velocity of water conveyed through pipes or conduits often exceeds the capacity of the receiving basin or channel to resist erosion.
scour at these sites, protect the outlet structure and minimize the potential for downstream
erosion, a flow transition structure is needed to absorb the initial impact of flow and reduce the
speed of the flow to a non-erosive velocity.
Aprons constructed from gabion mattresses placed at these
outlets will absorb energy to calm turbulence and slow the velocity of the discharged flow.
See Project Profiles featuring culvert outlets or headwalls
Download drawings of a typical culvert outlet or headwall.
Review the Design Guide or Assembly Guide for more information about using Modular Gabion Systems in your application