Updated Bioretention Standards

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1 , P.E. Division of Surface Water Ohio EPA Northwest District Office Reynolds Road - Toledo

2 Why would I use bioretention? Pollutant & Volume reduction To meet NPDES permit requirements CGP MSGP MS4 West Side Montessori - Lucas

3 NPDES Permit for Storm Water associated with Construction (CGP) Renewed April 21, Issued by Ohio EPA Still requires that bioretention areas are sized to treat the Water Quality Volume (WQv), but Reduced the target drain time from 40 hrs to 24 hrs

4 Rainwater and Land Development manual Provides Ohio s standards for storm water BMP construction Published by ODNR Is utilized by Ohio EPA to determine compliance with NPDES requirements for new construction and redevelopment where larger common plan disturbs 1 or more acre. Bioretention standards in manual updated October 21, /default.aspx

5 The term bioretention area includes: Bioretention Cell Turfed Linear Bioretention (formerly known as Dry Enhanced Swale) The term bioretention area does not include rain gardens. Rain gardens are best utilized in a retrofit scenario not subject to NPDES regulations for construction activity Can be approved by Ohio EPA on a case-by-case basis as an alternative post-construction BMP at regulated sites

6 With the publication of updates in the Rainwater manual, Ohio EPA expects engineers to design bioretention areas in accordance with new standards SWP3 reviewers should ensure that new standards are being utilized for bioretention design moving forward Bioretention areas can be designed with internal water storage (IWS) This does not mean that bioretention areas can now be located where they will intersect ground water A 1-ft separation from groundwater is required, with 2 feet recommended Purpose of IWS is to promote infiltration and allow denitrification

7 Bioretention on Brownfields Use must be evaluated on a case-by-case basis Brownfields Vacant Parcels Infill Redevelopment Better to locate on portions of site not impacted by prior use Impermeable liner and underdrain required in most situations upload/brownfield_infiltration_decision_tool.pdf

8 What I expect to see in the SWP3: Calculations, detailed plans & profile views Include stand alone O&M Plan: Designates entity for inspection & for maintenance List routine & non-routine maintenance tasks Inspection & maintenance schedule Any needed legally binding easements & agreements Map of all access & maintenance easements Pay attention to maintenance during design Expect regulated MS4s to review these as well

9 Questions? Contact Ohio EPA WILLIAMS MERCER DEFIANCE PAULDING VAN WERT FULTON HENRY PUTNAM AUGLAIZE ALLEN X3009 LUCAS HANCOCK HARDIN WOOD DSW NWDO Storm Water OTTAWA WYANDOT Manager- Elizabeth Wick x3002 Supervisor- Tom Poffenbarger x3000 SANDUSKY SENECA MARION CRAWFORD ERIE HURON Pat Tebbe RICHLAND Pat Tebbe ASHLAND Pat Tebbe Effective7/1/2014 (419) Patricia Tebbe (419) Or, visit our website at