indiana; green infrastructure and low impact development

8/3/2019 Indiana; Green Infrastructure and Low Impact Development

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Green Infrastructure and Low Impact

Development in Northwest Indiana

Conservation Design Forum | Northwestern Indiana Regional Planning Commission

USEPA | Northwest Indiana MS4 Community Partnership


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Two out of every threepeople in the world will befacing water shortages by2025global conflict will

inevitably resultUnited Nations


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Low Impact Development is a planning approach that

concentrates site development on areas leastsensitive to disturbance

uses distributed, on-site stormwater bestmanagement practices (BMPs) to emulate naturalhydrology, reduce runoff, and improve water quality.

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

necessary helps address: wet weather flows, Combined Sewer

Overflows, National Pollutant Discharge EliminationSystem permits, Total Maximum Daily Load permits,and Nonpoint Source Pollution Program goals.

can be applied to almost any element of thedeveloped landscapebuildings, yards, driveways,roads, walkways, open


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What kinds of strategies are used?

Conserving open space and protectingstreams, wetlands, and wet soils

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

Reducing and disconnecting impervioussurfaces (roads, sidewalks, rooftops)

Preserving and using the naturaltopography and drainage features of thelandscape, as well as some engineeredsystems, to manage stormwater, suchas


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Examples of stormwater BMPs

Natural landscape systems

Green roofs

Bioswales and rain gardens

Permeable paving

Rain barrels and cisterns

Naturalized retention


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Low Impact Development

Benefits

Preserves andintegrates open space

Creates / preservesnaturalized drainagesystems

Improves aesthetic

views

Protects water quality

Minimizes changes tothe natural hydrologic

cycle (less flooding)

Increases propertyvalue

Cost Implications

Reduces regulatoryburden (mitigation,

stormwater mgt)

Reduces site gradingand infrastructure costs

Reduces engineering

costs

Increases approvaltime / cost


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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 rightconditions for implementation

Stormwater management, drainage anddetention

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


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How are these practices integrated into development?

Site Design


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Site Design First Principles

Identify and protect natural features and openspace early

Use site topography and natural drainage patternsto guide site layout and stormwater management

Use the natural landscape and engineered,naturalized drainage and detention BMPs to filterand 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 spacethe total site area minus floodplains, wetlands,

waterways, steep slopes, natural areas

Concentrate built areas in a range of lot sizes andorientations to create views, privacy, and amenitiesfor each home


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Site Boundary

Wetlands

FloodplainSoils

Vegetation

Step 1: Identify sensitive areas


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Step 2: Identify development and restricted areas

Wetlands, floodplain,remnant woodlands

Hydric soilsHydric soils Site accessSite access TopographyTopography

No limitationsNo limitations


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Step 3: Develop site plan


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Permeable

paving and

rain gardens

Green roofs Bioswales Level

spreaders


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Merry Lea Environmental Learning Center, Wolf Lake, IN

Native LandscapePavement BaseBioswalesRain GardensWater reuse


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Conservation Design Templates

Moderate-Density Residential

Moderate Density Residential


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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


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Combined infrastructure &landscape cost 10% to 15% lessthan conventional template.

50% less detention required.

Native Landscaping

Bioswale

Naturalized Detention

Vegetated Swale/ RainGarden


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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. Site

Preparation1

2. Stormwater

Management

3. Sanitary

Sewer

4. Water

Distribution

5. Site

Paving and

Sidewalks

6. Landscape

Development

Design

Contingency2

Conventional

Conservation

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


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Commercial / Industrial / Multi-Family


Commercial/Industrial/Multi-Family


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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 landsca in

Green roof

garden for

second floor

units

Green roof

garden for

second floor

units


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Similar combined infrastructure andlandscaping cost as conventionaltemplate.

Significant potential for additionalcommercial space.


Bioswale

Green Roof

NaturalizedDetention

Porous

Pavement


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Rural Residential

Rural Residential


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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


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Combined infrastructure andlandscape cost 5% to 10% less than

the conventional template.


VegetatedSwale

Rain Garden

Naturalized Detention

Native Landscaping

R l R id ti l


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Rural Residential

$-

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

$700,000

1.Sit

ePrep

aration

2.Storm

water

Man

agem

ent

3.Sa

nitary

Sewer

Constru

ctedW

etlan

dPrem

ium

4.W

aterDist

ributi

on

5.Sit

ePa

vinga

ndSide

walks

6.La

ndscap

eDev

elopm

ent

Desig

nContin

gency

Conventional

Conservation

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



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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 StructuresInlets/Boxes/Headwalls

6,73310,098Linear Feet Drainage Pipe

07,360Linear Feet Collector Street

21,12521,770Linear Feet Street

375358Lot Yield

Sustainable PlanConventional PlanTotal Site

Projected 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 1

Actual Results from First Phase of Development



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A Comparison of Two Different Land Plans in Arkansas

More than $2,200,000 added to profitTotal Economic Benefit

National, state, and professional groupsRecognition

23.5 acres of green-space/parksAdded Amenities

80 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 Value

17 additional lotsHigher Lot Yield

Economic and Other Benefits From Low Impact Development


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indiana; green infrastructure and low impact development

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