Detention Basin Retrofits and Detention Basin Retrofits and EnhancementsEnhancements

November 29, 2007 November 29, 2007

Kelly C. Karll, P.E.Kelly C. Karll, P.E.

Senior Civil EngineerSenior Civil EngineerMichigan Water Environment AssociationMichigan Water Environment Association

Innovative Solutions for Storm Water ManagementInnovative Solutions for Storm Water Management

If converting a detention pond from If converting a detention pond from thisthis……

Before Construction 2002

……could result in this?could result in this?

……or this?or this?

Or retrofitting a pond from thisOr retrofitting a pond from this……

Before Construction 2002

……to this?to this?

After Construction July 2005

Or from thisOr from this……

……to this?to this?

Benefits of RetrofittingBenefits of Retrofitting

NPDES Phase II NPDES Phase II ProgramProgramWater quality Water quality improvementsimprovementsChannel protectionChannel protectionNative riparian and Native riparian and wetland vegetationwetland vegetationHabitat enhancementHabitat enhancementProperty owner Property owner acceptance and acceptance and ownershipownershipStorm water educationStorm water educationLower maintenance Lower maintenance costscosts

NPDES Phase II ProgramNPDES Phase II Program

Water quality Water quality enhancementsenhancements

Sediment forebaySediment forebayOutlet controlOutlet control--first flushfirst flush

Channel protectionChannel protectionOutlet controlOutlet control--bankfullbankfull

Water Quality EnhancementsWater Quality Enhancements

Reduce nonReduce non--point sources of pollution such as point sources of pollution such as sediments, oils, grease, nutrients & pesticides.sediments, oils, grease, nutrients & pesticides.

Native VegetationNative Vegetation

Wetland vegetationWetland vegetationPond ZonePond Zone

Edge ZoneEdge Zone

Riparian bufferRiparian bufferUpland ZoneUpland Zone

Benefits of Native VegetationBenefits of Native Vegetation

FloatingFloating--leaved plants leaved plants cool watercool water

Emergent plants near Emergent plants near the edge provide the edge provide habitat and water habitat and water filtering filtering

Trees, shrubs, prairie Trees, shrubs, prairie and meadow plants and meadow plants stabilize soil on banks stabilize soil on banks and deterand deter geesegeese

Habitat EnhancementHabitat Enhancement

Property Owner Acceptance & Property Owner Acceptance & Storm Water EducationStorm Water Education

NPDES Phase II NPDES Phase II Public education Public education planplan

StewardshipStewardship

Passive Recreational OpportunitiesPassive Recreational Opportunities

Bird watchingBird watching

Frog and toad surveysFrog and toad surveys

FishingFishingBluegill, Spotfin shiner, Banded killifish, Blackstripe topminnow, Brook silverside

Benthic surveysBenthic surveys

Nature photographyNature photography

Lower Maintenance CostsLower Maintenance Costs

Mow annually as Mow annually as opposed to weeklyopposed to weekly

Eliminate chemical Eliminate chemical treatmenttreatment

Minimize fountain Minimize fountain requestsrequests

Considerations for RetrofitsConsiderations for Retrofits

Outlet structure modificationsOutlet structure modifications

Addition of sediment Addition of sediment forebaysforebays

Modifications to eliminate shortModifications to eliminate short--circuitingcircuiting

Basin expansionsBasin expansions

Installation of outlet restrictorsInstallation of outlet restrictors

Installation of vegetative buffers and wetland Installation of vegetative buffers and wetland vegetationvegetation

Conversion of dry basins to wet basinsConversion of dry basins to wet basins

Factors to considerFactors to consider

Existing conditionsExisting conditionsProperty owner vs. Property owner vs. regulatory needsregulatory needsLand area constraintsLand area constraintsNonpoint source pollutantsNonpoint source pollutantsLongLong--term maintenance term maintenance expectationsexpectations

Frequency and duration of Frequency and duration of floodingflooding

Water depth and visibilityWater depth and visibility

Example Detention Basin RetrofitExample Detention Basin Retrofit

Ongoing ProblemsOngoing ProblemsAlgae GrowthAlgae Growth

Minimal Functioning Minimal Functioning Outlet PipeOutlet Pipe

Poor Water QualityPoor Water Quality

Invasive SpeciesInvasive Species

EnhancementsEnhancementsSediment ForebaySediment Forebay

New Outlet StructureNew Outlet Structure

Volunteer Planting Event Volunteer Planting Event

Wetland VegetationWetland Vegetation

Riparian BufferRiparian Buffer

Covington Square Subdivision, Canton TownshipCovington Square Subdivision, Canton Township

Construction ProcessConstruction ProcessCovington Square Subdivision, Canton TownshipCovington Square Subdivision, Canton Township

Final ResultsFinal Results

Example Detention Basin Example Detention Basin EnhancementsEnhancements

Detention Pond Buffer EnhancementsDetention Pond Buffer Enhancements

Example Detention Basin RetrofitExample Detention Basin Retrofit

Ongoing ProblemsOngoing ProblemsAlgae GrowthAlgae Growth

Plugged Outlet PipePlugged Outlet Pipe

EnhancementsEnhancementsNew Outlet StructureNew Outlet Structure

Volunteer Planting Volunteer Planting Event by Home OwnersEvent by Home Owners

Install Wetland Install Wetland VegetationVegetation

Construct Riparian Construct Riparian BufferBuffer

Meadowbrook Subdivision, Canton TownshipMeadowbrook Subdivision, Canton Township

Meadowbrook SubdivisionMeadowbrook Subdivision

Outlet Structure Outlet Structure ModificationsModifications

Meadowbrook SubdivisionMeadowbrook Subdivision

Outlet Structure Outlet Structure EnhancementEnhancement

Wetland & Buffer Wetland & Buffer PlantingsPlantings

Final ResultsFinal Results

Offer Opportunities to Enjoy Your Offer Opportunities to Enjoy Your Neighborhood AmenityNeighborhood Amenity

Park benches and Park benches and walking trailswalking trailsEducational signage Educational signage for homeownersfor homeownersCreate pondCreate pond--stewardship group stewardship group (kids and adults) to (kids and adults) to make maintenance make maintenance funfunHabitat Habitat opportunities (bird opportunities (bird boxes, logs)boxes, logs)

Opportunities are numerousOpportunities are numerous……

……benefits are obvious?benefits are obvious?

Before constructionBefore construction……

……after construction?after construction?

Before constructionBefore construction……

……After Construction?After Construction?

Thank youThank you

Questions or Comments?Questions or Comments?

Many photos courtesy of Canton Township