This system internally dissipates most of the energy produced by the water. Concrete Catch Basins, Plastic Drop Pipes and Steel Sloped Culverts are all examples of drop inlet spillways. View of an erosion control demonstration project which utilizes several drop inlet spillways. Grate structure in the foreground is an inlet for the central drop pipe. The incline height is normally greater than 1 m with no upper limit.
Common applications are gully control, surface water inlets to open ditches and terrace inlets.
Once water is in the spillway it is totally contained. The water does not rely on local soil conditions for erosion resistance. The spillway unit is normally prefabricated, reducing on site construction time. The unit has a limit to capacity. This makes it very suitable for floodwater storage systems.