BioretentionBioretention Cell DesignCell DesignDonald Carpenter, Ph.D. Donald Carpenter, Ph.D.

Lawrence Technological UniversityLawrence Technological University

January 26January 26thth, 2007, 2007Michigan Groundwater Stewardship ProgramMichigan Groundwater Stewardship Program

Bioretention Bioretention CellCell

Filter Bed

Additional Storage

Underdrain

Ponding

In-situ soils

Bioretention Bioretention CellCell

Lathrup Village, MICourtesy of Lillian Dean

Bioretention Bioretention CellCell

Madison, WisconsinCourtesy of Roger Bannerman

Bioretention Bioretention CellCell

Madison, WisconsinCourtesy of Roger Bannerman

Bioretention Bioretention CellsCells

Bioretention Bioretention CellsCells

BioretentionBioretention: Design Notes: Design NotesOverviewOverview

Key feature for LID/conservation designKey feature for LID/conservation designFocus on water quality volume ( ½” rain) Focus on water quality volume ( ½” rain) Remove TSS (85%), nutrients (50%) , metals Remove TSS (85%), nutrients (50%) , metals (95%), and hydrocarbons (80%)(95%), and hydrocarbons (80%)Planting mix comprised of sand, topsoil, and Planting mix comprised of sand, topsoil, and compost compost –– top with mulchtop with mulchProper landscaping is essential Proper landscaping is essential For site development For site development stormwater stormwater management should include overflow drainsmanagement should include overflow drainsLess than 1 ac total and ½ acre imperviousLess than 1 ac total and ½ acre impervious

BioretentionBioretention: Design Notes: Design NotesInfiltrationInfiltration

Hydraulic conductivity of inHydraulic conductivity of in--situ soils is keysitu soils is keyNeed inNeed in--situ soil information for infiltrationsitu soil information for infiltration

HSG maps (soil type A (1 to 3 in/hr); B (0.5 in/hr); C HSG maps (soil type A (1 to 3 in/hr); B (0.5 in/hr); C (0.2 in/hr); D (< 0.1 in/hr)(0.2 in/hr); D (< 0.1 in/hr)Soil borings & laboratory testsSoil borings & laboratory testsField infiltration testsField infiltration tests

Home testHome test18” hole 18” hole –– fill with water; drain, refill and recordfill with water; drain, refill and record

Improve infiltration by tilling, ripping or jettingImprove infiltration by tilling, ripping or jettingBottom should be 3 ft higher than seasonal g.w.t.Bottom should be 3 ft higher than seasonal g.w.t.

BioretentionBioretention: Design Notes: Design NotesSizingSizing

Minimum size is typically 10 ft by 20 ftMinimum size is typically 10 ft by 20 ftMinimum depth is 2.5 ftMinimum depth is 2.5 ftPondingPonding depth is typically 6” to 18”depth is typically 6” to 18”Recommend 24 to 48 hours to drain (< 72 Recommend 24 to 48 hours to drain (< 72 hours)hours)ii > 0.5 in/hr (or 1 in/hr) then basic design; > 0.5 in/hr (or 1 in/hr) then basic design; ii< 0.5 in/hr need < 0.5 in/hr need underdrainunderdrain

BioretentionBioretention CellCellDesign Equation (Darcy’s Law)Design Equation (Darcy’s Law)

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Note: if no underdrain than use infiltration rate (i) of existing soilsinstead of coefficient of permeability (k) if i < k

Bioretention Bioretention Cell Cell Design ExampleDesign Example

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Pavg

Copyright 2003, University of Wisconsin

Bioretention Bioretention Cell Cell Design ExampleDesign Example

Bioretention Bioretention Cell Cell Design ExampleDesign Example

DA 1

DA 2

References & ResourcesReferences & ResourcesNew York Stormwater Manual -

http://www.dec.state.ny.us/website/dow/toolbox/swmanual/Minnesota Stormwater Manual-

http://www.pca.state.mn.us/water/stormwater/stormwater-manual.html

USEPA Bioretention fact sheet -http://www.epa.gov/owm/mtb/biortn.pdf

Univ of Wisconsin DNR –http://clean-water.uwex.edu/pubs/home.htm#rain

LID Urban Design Tools -http://www.lid-stormwater.net/

SOCWA Healthy Lawns and Gardens -http://www.socwa.org/lawn_and_garden.htm

Rain Gardens of West Michigan -http://www.raingardens.org/Index.php

Prince George’s County, D.E.S. Bioretention -http://www.goprincegeorgescounty.com/Government/AgencyIndex/DER/ESD/Bioretention/bioretention.asp