green infrastructure retrofit opportunities

8/9/2019 Green Infrastructure Retrofit Opportunities

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Green InfrastructureRetrofit Opportunities

May 13, 2010

Dallas, TXDaniel P. Christian, PE, D.WRETetra [email protected]

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Agenda

Introduction Why Retrofit? Retrofit Basics

Objectives and criteria Desktop analysis Quantity estimation Field assessment and prioritization

IdeasCase Examples

Summary

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Solve ChronicFlooding Problems

Fix Past Mistakes &Maintenance Problems

Demonstration &Education

Reduce Pollutants ofConcern

3Photos: CWP

Reduce StormwaterRunoff Volumes

Support StreamRestoration Projects

Trap Trash &Floatables

Reduce DownstreamChannel Erosion

4Photos: CWP

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Retrofit verse New DevelopmentIntroduction

Retrofit New Development Higher costs

Sized to meet restoration objectives

Typically installed on public land

Compacted soils

Limited locations

Need neighborhood acceptance

Most are publicly maintained and thepublic expects that they will be

Not all candidate sites are feasible

Often tied into existing stormwaterconveyance system

Public investment dollars

Site visit is prerequisite for design

Designers seek least costly options

Sized to meet local design standards

Installed at new development projects

Soils are typically better

More location flexibility

More aesthetics flexibility

More options on maintenance, oftenrequire private maintenance

Nearly all sites are made to work

Usually creates the new stormwaterconveyance system

Private investment dollars

Design may occur without site visit

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Agenda



Ideas Case Examples Summary

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Private land willingnessby property ownersRoads (ROW)Open green spacesExisting BMPs that may bemodifiedIn-line storageopportunitiesLarge parking lotsHotspots

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Look For Basemaps for field

assessmentUse GIS

Topography Hydrology Aerial photographs

Utilities Soils Parcel boundaries Land use

Define ObjectiveRetrofit Basics

Clearly identify the overall objective, for example Store 1-inch of surface runoff and release over 24-hours

Infiltrate the first 1-inch of rainfall

Match natural hydrology

Reduce TSS by 80 percent

Capture 90% of trash and debris

Objectives may come from Watershed or storm water management plans

Permit requirements Modeling

Define general locations

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Desktop AnalysisRetrofit Basics

Prepare

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Estimate QuantityRetrofit Basics

Estimate area or volume needed for retrofits Example

Store the first 0.5-inches of runoff from a 1-acre parking lot Storage volume needed is 1,815 cubic feet Assume bioretention with 8-inches surface storage plus 4-foot of

engineered soil (25% void space) BMP yields 1.7 cubic feet of storage per square foot of area Therefore need = 1090 square feet or 2.5% of the parking area

Field Assessment and PrioritizationRetrofit Basics

Ownership

Access

Utility conflicts (up and down)

Soils

Topography water flowsdownhill

Inline verse offline

Existing stormwater BMPs

Education opportunitiesMaintenance

Brainstorming

Nearby vegetationPhotographsPublic acceptance

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Field Assessment and PrioritizingRetrofit Basics

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Field Assessment and PrioritizationRetrofit Basics

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Agenda



Ideas

Case Examples Summary

Green Roofs Individual PropertyIdeas

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Downspout Disconnect Individual PropertyIdeas

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Rain Barrel / Cistern Individual PropertyIdeas

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Rain Gardens Individual PropertyIdeas

Photo: Ward Wilson Tt17

Porous Pavement Impervious to PerviousIdeas

Photo: Abby Hall USEPA18

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Porous Pavers Impervious to PerviousIdeas

Photos: Abby Hall19

Green Impervious to PerviousIdeas

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Photo: LID Center Photo: LID Center

Photo: LID Center

Photo: Abby Hall

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Parking LotsIdeas

Parking LotsIdeas

Photo: Abby Hall USEPA



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Increased InfiltrationSpecific Ideas

Soil amendmentsSoil replacementsTilling/rippingVegetationIncreased residence time

Longer flow path Increased storage Increased resistance

Photo: Ward Wilson23

Between the curband the sidewalk

Photo: City of Vancouver Photo: Abby Hall USEPAPhoto: Bob Domm Tt24

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Into the Street


Swale StorageSpecific Ideas

Photo: Scott Struck Tt

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Roadway Boulevard


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Increased Local/Regional StorageSpecific Idea

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Agenda



Ideas Case Examples

Summary

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Tetra Tech Lansing Office (2006)Project by K&L Acquisitions, LLC and Tetra Tech

BEFORE

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Tetra Tech Lansing, MI Office (2006)Project by K&L Acquisitions, LLC and Tetra Tech

Tetra Tech Lansing Office (2006)Project by K&L Acquisitions, LLC and Tetra Tech

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NE Siskiyou Street (2003)Project by the City of Portland, designed by Kevin Perry

BEFORE

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0.00

0.05

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0.15

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0.25

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0.35

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09:30 09:45 10:00 10:15 10:30Time

Flow

(cfs)

InletOutlet

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NE Siskiyou Street (2003)Project by the City of Portland, designed by Kevin Perry Area

10,000 square foot total drainage area 600 square foot landscaping area (6% of drainage area)

Hydrology Modification (25-year flow test) 81% peak flow reduction

82% peak volume reduction

16 minute additional peak flow delay

Cost $17,000

Maintenance Semi-annual visits

Neighbors help at will

Successes

Incredible community acceptance of project Successful as a catalyst project for other green streets

Challenges Juncuspatensgrows too tall, needs annual trimming Unequal distribution of runoff due to crown of street

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ProjectSW 12thby the City of Portla

Avenue (2005)nd, designed by Kevin Perry

BEFORE

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SW 12th Avenue (2005)Project by the City of Portland, designed by Kevin Perry


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Area 7,500 square foot total drainage area 300 square foot landscaping area

(4% of drainage area)

Cost $35,000 ($117/sf)Maintenance - semi-annual visitsSuccesses Successful as a catalyst project for other urban green streets

Nobody has tripped yet (good to have 3 egress zone and 2landscape buffer zone at carriage walks)

Challenges Juncuspatensgrows too tall, needs annual trimming High loading of sediment requires more frequent cleaning

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Michigan AvenueLansing MI, by Tetra Tech and C2AE

Before


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MichiganAvenue

Lansing MIby Tetra Tech and C2AE


4 city blocks, both sides

Typical garden, no overflow for 1-inch event

600 block north side, no overflow for4.1-inches (25-year event)

$122/square foot 46

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Sandy Boulevard (2007)Project designed by Nevue Ngan Associates and URS

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15th Street and Sandy Blvd

After

After

Before

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21st Street and Sandy Blvd

Before

After

After

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22nd Street and Sandy Blvd

Before

After

After

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39th Street and Sandy Blvd

Before

After

After

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Harold Kelley Plaza and Sandy Blvd

Before

After

After

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School Courtyard Entry

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Mount Tabor Middle School (2006)Project by the City of Portland, designed by Kevin Perry and Brandon Wilson

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Mount Tabor Middle School (2006)Portland OR, designed by Kevin Perry and Brandon Wilson

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School Parking Lot

Before

Mount Tabor Middle

School (2006)Project by the City of Portland,designed by Kevin Perry and

Brandon Wilson

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Agenda



Ideas Case Examples Summary

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Summary Retrofits work to reduce problems in developed watersheds

When identifying retrofits begin by: Clearly identifying the objective and criteria

Start in the office gathering and organizing available information

Walk the site and look for opportunities

Think Reduce imperviousness

Increase infiltration and water uptake by plants

Provide storage Consider maintenance

Communicate your ideas

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Questions

green infrastructure retrofit opportunities

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