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Control Structures

  • Pond
    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. 

  • Silt Fence
    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.

  • Grass Filter
    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. 

  • Nonerodible 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.

  • Erodible Channel
    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.

  • Vegetated Channel
    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.

  • Riprap Channel
    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 method.

  • Culvert Sizing
    Culverts are used to convey runoff beneath roads.  The culvert design routine sizes the pipe based on headwater, tailwater, pipe characteristics, and peak flow requirements.

  • Plunge Pool
    A plunge pool is often used to dissipate energy at the down gradient outlet of a pipe to avoid developing a scour hole.

  • Null Structure
    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 control. 


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Last modified: 09/12/07.