Construction Site Diversion

CONSTRUCTION SITE DIVERSION

Code References

• "Channelized runoff from adjacent areas passing through the site shall be diverted around disturbed areas, if practical." (Reference: Section 290-7.2.e-1 of the City Code of Ordinances).

• "Diverted runoff shall be conveyed in a manner that will not erode the conveyance and receiving channels." (Reference: Section 290-7.2.e-1 of the City Code of Ordinances).

• "Erosion control measures shall be placed along down slope areas and along side slope areas as required to prevent or reduce erosion where erosion during construction will result in a loss of soil to waters of the state, public sewer inlets or off-site." (Reference: Section Comm 21.125(1)(a) of the Wisconsin Administrative Code).

 Quick Tips

• Diversion structures shall be inspected weekly at minimum and within 24 hours after a precipitation event of 0.5 inches or greater.

• Sediment deposits shall be properly disposed of when the deposits have accumulated to 1/2 the height of the diversion berm.

• Diversion can be used as a temporary storm water runoff control measure for the following conditions: (1) Above disturbed areas to limit runoff coming onto the site; (2) Across slopes to limit slope length; (3) Below slopes to divert runoff to stabilized areas; (4) To divert sediment laden runoff to treatment facilities; (5) At the perimeter of the the disturbed area to keep sediment retained on the construction site.

• Diversion berms shall have side slopes of 2 (horizontal) to 1 (vertical) or flatter and not be overtopped by the 2-year, 24-hour duration storm event.

• Diversion berms shall have a minimum top width of 2 feet and a minimum height of 1.5 feet.

• Diversion berms shall be stabilized as soon as they are constructed and prior to any down slope disturbances.

• When designing diversion berms, consider the use of an emergency overflow section to limit damage during storms exceeding the 2-year, 24-hour duration event.  Rip rap protection shall be provided at overflow sections.

Applicable Standard

• "Construction Site Diversion" (WDNR Technical Standard 1066). 

Related Weblink

• "Temporary Diversion Dikes" (USEPA - National Menu of Stormwater Best Management Practices).

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