The Pond structure type can be used for a sediment basin, or retention basin if
only hydrology is being used, a sediment trap, and an elongated sediment control
such as a terrace or bench with a controlled outlet.
A silt fence (or filter fabric fence) is a structure that is located in series
on the flow path of a slope or at the lower section of a slope. In series, it
reduces the slope length, L, in the RUSLE algorithm. A silt fence creates
backwater, thereby reducing transport capacity and enabling sediment deposition
of eroded particles.
A grass filter is a vegetated filter. It is only listed as an option when
sedimentology is enabled.
Porous Rock Check Dam
The check dam is a porous rock check dam located in a channel.
The nonerodible channel is simply solved using Manning’s equation and the
continuity equation. It is used for concrete channels and commercial
products that base their design on Manning's n solutions.
A channel consisting of bare soil or spoil is modeled as an erodible channel.
The limiting permissible velocity method is used that accommodates the design of
channels conveying both clear and sediment-laden water. Various commercial
products that base their design on a specified critical velocity can be designed
using this algorithm. Erodible channels are often designed to convey
sediment-laden water to sediment controls.
A vegetated channel is a grass waterway. It is used to permanently stabilize
areas during the final phase of reclamation or site development. Designs are
based on channel stability and capacity requirements.
Rock riprap is used to stabilize a channel conveying a large quantity of runoff
on steeper slopes. It may be a temporary or permanent channel stabilization
Culverts are used to convey runoff beneath roads. The culvert design routine
sizes the pipe based on headwater, tailwater, pipe characteristics, and peak
A plunge pool is often used to dissipate energy at the down gradient outlet of a
pipe to avoid developing a scour hole.
The Null structure is used to output data at a specified location. It can also
be used as a place-holder where alternative control structures can be
substituted for the Null structure. This enables the user to determine the
effectiveness of alternative controls, at a specific location, versus having no