Construction Site Permitting and

New Bioretention Standards

Chris Cotton

Stormwater Program Coordinator

Ohio EPA – Southwest District Office

Christopher.cotton @ epa.ohio.gov

937.285.6442

OEPA’s Construction General PermitOEPA’s Construction General Permit

Revised every 5 yearsRevised every 5 years ESC at active construction sites, andESC at active construction sites, and Proper mgmt of materials, wasteProper mgmt of materials, waste “ “Post-construction” runoff mgmt toPost-construction” runoff mgmt to

Improve water quality Improve water quality Protect stream stability/functionProtect stream stability/function

Post-ConstructionPost-Construction & the & the “Water Quality Volume”“Water Quality Volume” (p 18 of CGP) (p 18 of CGP)

WQv = C x P x A/12 WQv = C x P x A/12 C = runoff coefficientC = runoff coefficient P = 0.75 inches of rain P = 0.75 inches of rain

A = area draining to BMPA = area draining to BMP

-- BMPs listed in permit (p 21) -- BMPs listed in permit (p 21)

-- Alternative BMPs => OEPA approval-- Alternative BMPs => OEPA approval

Bioretention as Post-con BMPBioretention as Post-con BMP

• Size to handle all (or part) of a siteSize to handle all (or part) of a site• • 24 hour draindown 24 hour draindown •• Rain gardens not considered bioretentionRain gardens not considered bioretention

• Lack specific design standardsLack specific design standards• Rain gardens typically smallRain gardens typically small• Better suited for retrofitsBetter suited for retrofits

• Erosion/Sediment Control BMPs Erosion/Sediment Control BMPs

• Post-con standards (Chapter 2)Post-con standards (Chapter 2)• http://www.dnr.state.oh.us/tabid/9186/default/aspxhttp://www.dnr.state.oh.us/tabid/9186/default/aspx

Bioretention Standards Updated 10/13Bioretention Standards Updated 10/13