LID Cost ConsiderationsLID Cost Considerations“ALL Technologies”“ALL Technologies”

Project Life CycleProject Life Cycle

Planning Design

ConstructionOperation

MaintenanceRecapitalizationDecommission

Conventional 244 Lots

Cantura Coves: Cantura Coves: Mesquite, TexasMesquite, TexasD.R. Horton 241 Coved LotsD.R. Horton 241 Coved Lots

Cantura Coves: Cantura Coves: Mesquite, TexasMesquite, TexasD.R. Horton 241 Coved LotsD.R. Horton 241 Coved Lots

Coving:Coving:42% Less Street42% Less Street40% Larger Lots40% Larger LotsMeandering WalksMeandering Walks

3.7

Per A

c

3.7

Per A

c

3.7 Per A

c

3.7 Per A

c

3.7 Per Ac

3.7 Per Ac

Photo: Cantura Cove – Mesquite, Texas

Placitas de La Paz: Placitas de La Paz: Coachella, CaliforniaCoachella, CaliforniaCanaday & CompanyCanaday & Company271 Coved Lots271 Coved Lots

Coving:Coving:

42% Less Street42% Less Street

Same Avg. Lot Size.Same Avg. Lot Size.

Connective WalksConnective Walks

31 MORE Lots!31 MORE Lots!

Conventional Coved

City of Coachella, CaliforniaCity of Coachella, CaliforniaRESIDENTIAL PROJECT RESIDENTIAL PROJECT

OF THE YEAROF THE YEAR20022002

Awarded for Providing Awarded for Providing Beautiful, QualityBeautiful, Quality

Affordable HousingAffordable Housing

Construction Cost ComparisonConstruction Cost Comparison

Patuxent Riding

Conventional Low Impact

Grading /Roads 569,698$ 426,575$

StormDrains 225,721$ 132,558$

SWM Pond / Fees 260,858$ 10,530$

Bioretention / Micro -$ 175,000$

Total 1,086,277$ 744,663$

Unit Cost 14,679$ 9,193$

Green - LIDGreen - LID

Yellow - Conventional Yellow - Conventional

 A Comparison of Two Different Land Plans  

PROJECTED RESULTS FROM TOTAL DEVELOPMENT

Total SiteLot YieldLinear Feet - StreetLinear Feet - Collector StreetLinear Feet - Drainage PipeDrainage Sections(Inlets, Boxes, Headwalls)Estimated Total Cost

Conventional Plan35821,7707,36010,098103

$4.6 million

Revised Green Plan37521,12506,73379 $3.9 million

   

ACTUAL RESULTS FROM PHASE ONE

Total Site (engineer’s estimate)Lot YieldTotal Cost Cost Per Lot

Conventional Plan

63$1,028,544$16,326

Green Plan

 72828,523$11,507

   

ECONOMIC AND OTHER BENEFITS FROM LOW-IMPACT DEVELOPMENT

Higher Lot YieldHigher Lot ValueLower Cost per Lot Enhanced Marketability Added Amenities Recognition

17 additional lots$3,000 more per lot than competition$4,800 less per lot80 percent of lots sold in the first year23.5 acres of green space/parksNational, state, and professional groups

  

TOTAL ECONOMIC BENEFIT More than $2.2 million in savings.

No Cost Stuff No Cost Stuff

1.1. Site Design to Conserve Terrestrial FunctionsSite Design to Conserve Terrestrial Functions

2.2. Disconnection Disconnection

3.3. Grading TechniquesGrading Techniques

4.4. Distributed Controls Distributed Controls

5.5. Multifunctional Use of SpaceMultifunctional Use of Space

6.6. Less Grading and Clearing Less Grading and Clearing

““Optimize the use of these smart design techniques” Optimize the use of these smart design techniques”

Rain Garden Treatment Train Approach

Bioretention CellStorm Drain System

Bioretention Cell

Flow Path

Grass Swale Grass Filter Strip

Rain Gardens

Conventional Conventional DevelopmentDevelopment

Stormwater Pond Problems

• High Design / Construction Costs

• Moderate Maintenance– Functional / Aesthetics

• Consumes Land / Resources

• Limited Effectiveness

• Disease

• Public Safety

LID Development

Conservation Conservation Minimization Minimization Soil Soil Management Management Open Drainage Open Drainage Rain Gardens Rain Gardens Rain Rain Barrels Barrels Pollution Pollution Prevention Prevention

Conservation Conservation Minimization Minimization Soil Soil Management Management Open Drainage Open Drainage Rain Gardens Rain Gardens Rain Rain Barrels Barrels Pollution Pollution Prevention Prevention

Disconnected Disconnected Decentralized Decentralized Distributed Distributed Multi-functional Multi-functional

Disconnected Disconnected Decentralized Decentralized Distributed Distributed Multi-functional Multi-functional

Multiple SystemsMultiple Systems

No Cost Stuff No Cost Stuff

1.1. Site Design to Conserve Terrestrial FunctionsSite Design to Conserve Terrestrial Functions

2.2. Disconnection Disconnection

3.3. Grading TechniquesGrading Techniques

4.4. Distributed Controls Distributed Controls

5.5. Multifunctional Use of SpaceMultifunctional Use of Space

6.6. Less Grading and Clearing Less Grading and Clearing

““Optimize the use of these smart design techniques” Optimize the use of these smart design techniques”

Construction Cost ComparisonConstruction Cost Comparison

Patuxent Riding

Conventional Low Impact

Grading /Roads 569,698$ 426,575$

StormDrains 225,721$ 132,558$

SWM Pond / Fees 260,858$ 10,530$

Bioretention / Micro -$ 175,000$

Total 1,086,277$ 744,663$

Unit Cost 14,679$ 9,193$

Rain Garden Treatment Train Approach

Bioretention CellStorm Drain System

Bioretention Cell

Flow Path

Grass Swale Grass Filter Strip

Rain Gardens

Somerset Cost Savings

• $780,000 Total Cost Savings – Eliminated

• Curb / Gutter $350,000• 4 stormwater ponds $650,000• Pipes / Structures $150,000

– Added • $370,000 for Rain Gardens

Bioretention Bioretention • Shallow Ponding - 4” to 6”

• Soil Depth 2’ - 2.5’

• Sandy Top Soil

• 50% Sand

• 20% Sandy Loam

• 30% Compost

• Under Drain System

• Plant Selection

Aesthetic Value / Habitat Value

Property Value / Low Cost

Low Maintenance

X 2’

Under Drain

Proprietary Devices

2” Mulch

Sandy Filter Media

Drain Pipe

Storm Drain

Roadway

A Grow ing Idea in Stormwater Filt ration.

Optional Infiltration Storage

Volatilization

BioretentionClean-out

Rip-Rap

Biodegradation

Root Uptake

Drains to infiltration storage

Tree Grate

Rain Garden on a commercial project with turf grass near I-395 and Edsall Road.

Rain Garden longitudinal view showing overflow device.

Cost Comparison Proprietory BMP's

Device Type Unit Cost Main.Cost Annual

Storm Solutions Absrobant 5,500$ 455$ Ab Tech Absrobant 5,000$ 1,600$ Bay Saver Hydrodynamic 6,700$ 2,000$ Vortechnics Hydrodynamic 12,000$ 2,000$ CDS Hydrodynamic 15,000$ 2,000$ Fossil Filter Filter Inlet Insert 5,400$ 6,300$ Stormceptor Hydrodynamic 34,570$ 2,000$ Stormtreat Filter Wetland 33,000$ 4,500$ Stormfilter Filter Cartrages 40,000$ 5,000$ Filterra Bioretention 6,000$ 100$

High Flow Rate Filter and Infiltration

Treats 90% of Total Annual Volume

Maintenance Cost - $200 / Year

Perspectives on Perspectives on Implementing Implementing Low-Impact Low-Impact

Developments since 1998Developments since 1998

Waukesha, WisconsinWaukesha, Wisconsin

Use native species in restoring open spaces and in lot bioretetnion landscapingUse native species in restoring open spaces and in lot bioretetnion landscaping

© Applied Ecological Services, Inc.

Home and Lot SalesHome and Lot Sales

Conventional Conventional Village of Jackson

Lot Size: 7,000 – 8,000 ft2

Price: low-mid $40,000$40,000

Low ImpactLow ImpactPrairie Meadows

Lot Size: 7,000 – 8,000 ft2

Price: mid-high $50,000$50,000

Advantages of LID Over Advantages of LID Over Conventional DesignConventional Design

Advantages of LID Over Advantages of LID Over Conventional DesignConventional Design

Added Value of LID Results in:Added Value of LID Results in:

• Lot PremiumsLot Premiums

• Increased Sales VelocityIncreased Sales Velocity

• Increased Sales Volume Increased Sales Volume

• Reduced Debt Service Reduced Debt Service

• Reduced Infrastructure CostsReduced Infrastructure Costs

Lessons Learned Nature Sells!Lessons Learned Nature Sells!Lessons Learned Nature Sells!Lessons Learned Nature Sells!

Biggest Obstacles to LIDBiggest Obstacles to LID

Local Ordinances Local Ordinances and and

Knowledge / Experience Knowledge / Experience of of

Local Building Officials Local Building Officials & &

Consultants!Consultants!

Biggest Obstacles to LIDBiggest Obstacles to LID

Local Ordinances Local Ordinances and and

Knowledge / Experience Knowledge / Experience of of

Local Building Officials Local Building Officials & &

Consultants!Consultants!