Monday, January 18, 2010

South Dakota General Stormwater Discharge Permit - Construction

On February 1, 2010, the revised NPDES discharge permit for construction site stormwater discharges takes effect in South Dakota. The South Dakota Department of Environment & Natural Resources (DENR) issued the revised permit on December 31, 2009; this permit replaced the previous, which had been issued in 2002 and has been expired since 2007. The revised permit makes a number of changes to the stormwater compliance requirements needing to be met at affected construction sites.

Some of the key requirements include:

  • NOI must be signed by the owner
  • SWPPP must be developed before the NOI is submitted
  • All SWPPPs, inspection reports, or other information must be signed and certified by a signatory official or by a “duly authorized representative” (Signatory authority must identify authorized representative and submit written authorization letter to DENR)

Stormwater Controls

  • Controls must be designed to meet 2 inch 24 hour event (2-year, 24-hour storm event)
  • Sediment basins required if >10 acres disturbed at one time, where possible
  • Sediment traps or other equivalent controls required if <10>
  • All storm drain inlets must be protected until site is stabilized
  • Install velocity dissipation devices at points with high flows
  • Soil stockpiles must have silt fence or other effective controls Properly store and dispose of litter, construction debris, and chemicals
  • Once every 7 days
  • Within 24 hours after storm that is 0.5 inches or greater
  • Remove sediment when ponds are 50% full
  • Clean silt fences before sediment is 50% of the fence height
  • Must minimize dust generation and tracking; street sweeping required at a minimum
  • Remove sediment that accumulates off-site
  • Site must be stabilized within 14 days after construction has ceased at the site

Caltha LLP provides expert consulting services to public and private sector clients nationwide to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.

For further information contact Caltha LLP at
Caltha LLP Website

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