Green Infrastructure and Low Impact Development in Northwest Indiana

Conservation Design Forum | Northwestern Indiana Regional Planning Commission

USEPA | Northwest Indiana MS4 Community Partnership

Two out of every three people in the world will be facing water shortages by 2025…global conflict will inevitably result…

United Nations

Low Impact Development is a planning approach that

• concentrates site development on areas least sensitive to disturbance

• uses distributed, on-site stormwater best management practices (BMPs) to emulate natural hydrology, reduce runoff, and improve water quality.

• BMPs can be simple, nonstructural, low-tech, and low cost (e.g., vegetation), more complex when necessary

• helps address: wet weather flows, Combined Sewer Overflows, National Pollutant Discharge Elimination System permits, Total Maximum Daily Load permits, and Nonpoint Source Pollution Program goals.

• can be applied to almost any element of the developed landscape—buildings, yards, driveways, roads, walkways, open

What kinds of strategies are used?

• Conserving open space and protecting streams, wetlands, and wet soils

• Reducing the use (and cost) of pipes, detention ponds, curbs and gutters, mass site clearing and grading, and paving

• Reducing and disconnecting impervious surfaces (roads, sidewalks, rooftops)

• Preserving and using the natural topography and drainage features of the landscape, as well as some engineered systems, to manage stormwater, such as…

Examples of stormwater BMPs

• Natural landscape systems

• Green roofs

• Bioswales and rain gardens

• Permeable paving

• Rain barrels and cisterns

• Naturalized retention

Low Impact Development

Benefits

• Preserves and integrates open space

• Creates / preserves naturalized drainage systems

• Improves aesthetic views

• Protects water quality

• Minimizes changes to the natural hydrologic cycle (less flooding)

• Increases property value

Cost Implications

• Reduces regulatory burden (mitigation, stormwater mgt)

• Reduces site grading and infrastructure costs

• Reduces engineering costs

• Increases approval time / cost

Create Conditions to Support Low Impact Development

• Establish local commitment and support

• Policies, funding, incentives, practices, standards, rules, codes and regulations must point in the same direction to create the right conditions for implementation

• Stormwater management, drainage and detention

• Natural area protection and management

• Landscaping

• Parking and transportation

• Zoning and subdivision standards

• Block and lot dimensions and setbacks

• Street and sidewalk dimensions

•Development density, lot yield, and ‘bulk’

How are these practices integrated into development?

Site Design

Site Design “First Principles”

• Identify and protect natural features and open space early

• Use site topography and natural drainage patterns to guide site layout and stormwater management

• Use the natural landscape and engineered, naturalized drainage and detention BMPs to filter and infiltrate stormwater on site

• Reduce the impervious area of development• Allow flexibility in lot size, street, block, and lot

layout• Calculate site yield based on developable space—

the total site area minus floodplains, wetlands, waterways, steep slopes, natural areas…

• Concentrate built areas in a range of lot sizes and orientations to create views, privacy, and amenities for each home

Site BoundaryWetlandsFloodplainSoilsVegetation

Step 1: Identify sensitive areas

Step 2: Identify development and restricted areas

Wetlands, floodplain, remnant woodlands

Hydric soilsHydric soils Site accessSite access TopographyTopography

No limitationsNo limitations

Step 3: Develop site plan

Permeable paving and rain gardens

Green roofs Bioswales Level spreaders

Merry Lea Environmental Learning Center, Wolf Lake, IN

Native LandscapePavement BaseBioswalesRain GardensWater reuse

Conservation Design Templates

Moderate-Density Residential

Moderate-Density Residential

Conventional (90 lots)• Wide roads• No public open space• Storm sewers that discharge into

turf or rip-rap-lined detention basins

Conservation (90 lots)• Narrower streets• Integrated, naturalized stormwater

system• Public trails and open space• Views of naturalized open space

• Combined infrastructure & landscape cost 10% to 15% less than conventional template.

• 50% less detention required.

Native Landscaping

Bioswale

Naturalized Detention

Vegetated Swale/ Rain Garden

Moderate Density Residential

$-

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

$700,000

$800,000

$900,000

$1,000,000

1. SitePreparation1

2. StormwaterManagement

3. SanitarySewer

4. WaterDistribution

5. Site Paving andSidewalks

6. LandscapeDevelopment

DesignContingency2

ConventionalConservation

Conventional $3,350,000 ($37,600/lot) / Conservation $2,880,000 ($32,400/lot)

Commercial / Industrial / Multi-Family

Conservation Design Templates

Commercial/Industrial/Multi-Family

• Typical strip mall• Two “big box” retail

establishments • Isolated outlet shops• Parking, landscaping, and

detention according to code

• “Main Street” retail setting• “Big box” retail incorporates

green roof• Second floor mixed-use areas• Parking areas feature

permeable paving, bioswales, and naturalized landscaping

Green roof garden for

second floor units

Green roof garden for

second floor units

• Similar combined infrastructure and landscaping cost as conventional template.

• Significant potential for additional commercial space.

• 40% less detention required.

Bioswale

Green Roof

Naturalized Detention

Porous Pavement

Conservation Design Templates

Rural Residential

Rural Residential

Conventional (22 lots) • Cul-de-sac design• Storm sewers discharge into

detention basins

Conservation Design (22 lots)• Narrow lane streets• Naturalized stormwater detention• Naturalized landscaping• Walking and biking trails

• Combined infrastructure and landscape cost 5% to 10% less than the conventional template.

• 70% less detention required.

Vegetated Swale

Rain Garden

Naturalized Detention

Native Landscaping

Rural Residential

$-

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

$700,000

1. Site

Prep

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n

2. Stor

mwater M

anag

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Sanita

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Constr

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Wetl

and P

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4. W

ater D

istrib

ution

5. Site

Pav

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walks

6. La

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ign C

ontin

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y

ConventionalConservation

Conventional $1,570,000 ($71,000/lot) / Conservation $1,470,000 ($67,000/lot)

Low Impact Development A Comparison of Two Different Land Plans in Arkansas

$10,512$12,907Estimated Cost per Lot

$3,942,100$4,620,600Estimated Total Cost

79103Drainage Structures Inlets/Boxes/Headwalls

6,73310,098Linear Feet Drainage Pipe

07,360Linear Feet Collector Street

21,12521,770Linear Feet Street

375358Lot Yield

Sustainable PlanConventional PlanTotal SiteProjected Results From Total Development

$11,507$16,326Total Cost Per Lot

$828,523$1,028,544Total Cost

7263Lot Yield

Sustainable Plan(Actual Figures)

Conventional Plan(Engineer's Estimate)

Phase 1Actual Results from First Phase of Development

Low Impact Development A Comparison of Two Different Land Plans in Arkansas

More than $2,200,000 added to profitTotal Economic BenefitNational, state, and professional groupsRecognition23.5 acres of green-space/parksAdded Amenities80 percent of lots sold in first yearEnhanced Marketability$4,800 less cost per lotLower Cost Per Lot$3,000 more per lot over competitionHigher Lot Value17 additional lotsHigher Lot Yield

Economic and Other Benefits From Low Impact Development