DENR Revised Construction Stormwater Permit

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 changes include:

Permit

• 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

Inspections

• Once every 7 days
• Within 24 hours after storm that is 0.5 inches or greater

Maintenance

• 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 environmental consultant services in South Dakota to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.


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