Green Infrastructure and Low Impact Development

1. Green Infrastructure and Low Impact
Development in Northwest Indiana
Conservation Design Forum | Northwestern Indiana Regional Planning Commission
USEPA | Northwest Indiana MS4 Community Partnership

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

11. 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

12. 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…

13. Examples of stormwater BMPs
• Natural landscape systems
• Green roofs
• Bioswales and rain gardens
• Permeable paving
• Rain barrels and cisterns
• Naturalized retention

14. Low Impact Development
Benefits Cost Implications
• Preserves and • Reduces regulatory
integrates open space burden (mitigation,
stormwater mgt)
• Creates / preserves
naturalized drainage • Reduces site grading
systems and infrastructure costs
• Improves aesthetic • Reduces engineering
views costs
• Protects water quality • Increases approval
time / cost
• Minimizes changes to
the natural hydrologic
cycle (less flooding)
• Increases property
value

15. 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’

16. How are these practices integrated into development?
Site Design

17. 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

18. Site Boundary
Wetlands
Floodplain
Soils
Vegetation
Step 1: Identify sensitive areas

19. Wetlands, floodplain,
remnant woodlands
No limitations
Hydric soils Site access Topography
Step 2: Identify development and restricted areas

20. Step 3: Develop site plan

28. Permeable Green roofs Bioswales Level
paving and spreaders
rain gardens

30. Merry Lea Environmental Learning Center, Wolf Lake, IN
Water Landscape
Rain Gardens
Bioswales
Pavement Base
Native reuse

34. Conservation Design Templates
Moderate-Density Residential

35. Moderate-Density Residential
Conventional (90 lots) Conservation (90 lots)
• Wide roads • Narrower streets
• No public open space • Integrated, naturalized stormwater
• Storm sewers that discharge into system
turf or rip-rap-lined detention basins • Public trails and open space
• Views of naturalized open space

36. Native Landscaping Naturalized Detention
Bioswale Vegetated Swale/ Rain
Garden
• Combined infrastructure &
landscape cost 10% to 15% less
than conventional template.
• 50% less detention required.

37. Moderate Density Residential
Conventional $3,350,000 ($37,600/lot) / Conservation $2,880,000 ($32,400/lot)
$1,000,000
$900,000
$800,000
$700,000
$600,000
Conventional
$500,000
Conservation
$400,000
$300,000
$200,000
$100,000
$-
1. Site 2. Stormwater 3. Sanitary 4. Water 5. Site 6. Landscape Design
Preparation1 Management Sewer Distribution Paving and Development Contingency2
Sidewalks

38. Conservation Design Templates
Commercial / Industrial / Multi-Family

39. Commercial/Industrial/Multi-Family
Green roof
garden for
second floor
units
Green roof
garden for
second floor
units
• Typical strip mall • “Main Street” retail setting
• Two “big box” retail • “Big box” retail incorporates
establishments green roof
• Isolated outlet shops • Second floor mixed-use areas
• Parking, landscaping, and • Parking areas feature
detention according to code permeable paving, bioswales,
and naturalized landscaping

40. Bioswale Naturalized
Detention
Green Roof Porous
Pavement
• Similar combined infrastructure and
landscaping cost as conventional
template.
• Significant potential for additional
commercial space.
• 40% less detention required.

41. Conservation Design Templates
Rural Residential

42. Rural Residential
Conventional (22 lots) Conservation Design (22 lots)
• Cul-de-sac design • Narrow lane streets
• Storm sewers discharge into • Naturalized stormwater detention
detention basins • Naturalized landscaping
• Walking and biking trails

43. Vegetated Naturalized Detention
Swale
Rain Garden Native Landscaping
• Combined infrastructure and
landscape cost 5% to 10% less than
the conventional template.
• 70% less detention required.

44. Rural Residential
Conventional $1,570,000 ($71,000/lot) / Conservation $1,470,000 ($67,000/lot)
$700,000
$600,000
$500,000
$400,000
Conventional
Conservation
$300,000
$200,000
$100,000
$-
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45. Low Impact Development
A Comparison of Two Different Land Plans in Arkansas
Projected Results From Total Development
Total Site Conventional Plan Sustainable Plan
Lot Yield 358 375
Linear Feet Street 21,770 21,125
Linear Feet Collector Street 7,360 0
Linear Feet Drainage Pipe 10,098 6,733
Drainage Structures 103 79
Inlets/Boxes/Headwalls
Estimated Total Cost $4,620,600 $3,942,100
Estimated Cost per Lot $12,907 $10,512
Actual Results from First Phase of Development
Phase 1 Conventional Plan Sustainable Plan
(Engineer's Estimate) (Actual Figures)
Lot Yield 63 72
Total Cost $1,028,544 $828,523
Total Cost Per Lot $16,326 $11,507

46. Low Impact Development
A Comparison of Two Different Land Plans in Arkansas
Economic and Other Benefits From Low Impact Development
Higher Lot Yield 17 additional lots
Higher Lot Value $3,000 more per lot over competition
Lower Cost Per Lot $4,800 less cost per lot
Enhanced Marketability 80 percent of lots sold in first year
Added Amenities 23.5 acres of green-space/parks
Recognition National, state, and professional groups
Total Economic Benefit More than $2,200,000 added to profit