2. There’s a lot we’re doing well…
Chapel Hill’s stormwater performance standards (particularly volume
control); Resource Conservation District Ordinance for stream buffers
Carrboro’s water quality buffers and village mixed use standards
Orange County’s Flexible Development Ordinance for Conservation Design
UNC’s stormwater standards for Central Campus and cutting-edge plans for
Carolina North
Drinking Water Supply Protection standards
Urban Services Area boundary and Rural Buffer
Orange County’s Land Legacy Program for land preservation
Carrboro and Chapel Hill’s 5,000 sq.ft. threshold for stormwater
management
Tree protection standards
Progressive Sedimentation and erosion control standards
Etc.
2
3. 5 Key Points – To be more successful we need to…
Address uncontrolled runoff from
existing development
Be realistic about what can be
achieved in restoring our streams
Build on our strong stormwater
performance standards
Consider new incentives and
requirements for green practices
Select practices that provide
multiple benefits
6. Development Impacts: Overland Pollutant Loading
25 3
20 2.5
Forest 2 Forest
lb/ac/yr
lb/ac/yr
15
Res (½ ac) Res (½ ac)
1.5
10 Industrial Industrial
1
Commercial Commercial
5 0.5
0 0
Total Nitrogen Total Phosphorus
0.25
0.2
Forest
tons/ac/yr
0.15
Res (½ ac)
0.1 Industrial
Commercial
0.05
0
TSS
7. A word of caution. New research shows…
Most stream restoration efforts are unsuccessful.
Focusing on isolated stream reaches,
Ignoring what’s upstream and runoff from the watershed
Removing tree canopy and disturbing riparian areas
Most urban stream restoration efforts promise more
than they can achieve.
Ignoring real biological and water quality potential
7
8. Redevelopment Standards
New State Jordan Lake Stormwater Rules for
redevelopment have stricter
stormwater capture and treatment standards and
streamside vegetation rules
As existing development in Carrboro, Chapel Hill,
and Orange County redevelops, the Rules will also
benefit local streams.
8
9. How can we proactively reduce impacts from
existing development?
9
18. How can we pay for these retrofits?
State DOT- Local Partnership
Stormwater fees
Chapel Hill has a fee; Carrboro doesn’t
Wastewater utility fees (Fayetteville, Ark., Portland,
Philadelphia, etc.)
Trading (Washington, D.C)
Private-Public Cost Sharing (Raleigh)
18
19. Wastewater Utility Fee Example Fayetteville Ark
State proposed strict, costly wastewater discharge
Phosphorus limit.
Agreed to allow the treatment plant to continue to
meet current limit IN EXCHANGE FOR reducing
nonpoint source loading in watershed.
The City agreed to pay $200,000/yr for retrofit and
restoration projects.
19
20. Trading Program Example Washington D.C.
Washington D.C. Stormwater Retention Trading
Program
Increases retention of stormwater at all regulated
development
Dense downtown areas allowed to purchase credits
Less dense regulated and unregulated areas can install
BMPs that generate retention credits
Provides more flexibility and cost-effectiveness
20
21. Cost-Share Program Example City of Raleigh
Up to 50-50 cost-share for private development
BMP retrofits for existing development
BMPs on new construction
Must go beyond regulatory requirements
Bioretention Area
21
23. Traditional Thinking
Old wisdom: Treating the first inch of runoff and
managing the peaks of stormwater is enough.
Now we know it’s not.
23
24. Changes in Flow
2-yr 24-hr storm
70
Existing
60
Post, no BMPs
50
Conventional Detention
40
cfs
30
20
10
0
10:00 AM 11:00 AM 12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM
25. Performance Standard Gap
Carrboro and Orange County: Volume Control
Example Language from Chapel Hill Ordinance
“The stormwater runoff volume leaving the site post-
development shall not exceed the stormwater runoff volume
leaving the pre-development site (existing conditions) for the
local 2-year frequency, 24-hour duration storm event for all
development.” except certain residential development existing
1/27/03.
25
26. Jordan Lake Stormwater Rules – What’s New?
Nutrient loading limits for all new development and
redevelopment
In addition to treatment of 1st inch and peak control
Protection of existing riparian buffers – 50 feet of
vegetation – no clearing, grading, or development
(existing lawns are exempted)
Also applies to state and federal entities, e.g. DOT
26
28. The Green Factor and Green Area Ratio: Seattle and
Washington D.C.
“Green Area Ratio (GAR) is the ratio of the weighted value
of landscape elements to land area. The GAR score
relates to an increase in the quantity and quality of
environmental performance of the urban landscape”.
28
Pictures courtesy Laine Cidlowski
29. Green Area Ratio Benefits
Increases the amount and quality of urban
landscaping in dense urban areas
Also applicable to low and moderate density zones
Allows increased flexibility for developers and
designers to efficiently use their properties
Builds on stormwater requirements
29
30. GREEN AREA RATIO LANDSCAPE ELEMENTS MULTIPLIER
Landscaped area (select one of the following for each area)
Landscaped areas with a soil depth of less than 24 in. 0.3
Landscaped areas with a soil depth of 24 in. or more 0.6
Bioretention facilities 0.4
Plantings
Ground covers, or other plants less than 2 ft tall at maturity 0.2
Plants at least 2 ft tall at maturity 0.3
Tree canopy for all trees 2.5 in. to 6 in. in diameter 0.5
Tree canopy for new trees 6 in. in diameter or larger 0.6
Tree canopy for preservation of existing trees 6 in. to 24 in. in diameter 0.7
Tree canopy for preservation of existing trees 24 in. diameter or larger 0.8
Vegetated wall, plantings on a vertical surface 0.6
Vegetated roofs
Extensive vegetated roof over at least 2 in. but less than 8 in. of growth medium 0.6
Intensive vegetated roof over at least 8 in. of growth medium 0.8
Water features (using at least 50% recycled water) 0.2
Permeable paving
Permeable paving over at least 6 in. and less than 2 ft of soil or gravel 0.4
Permeable paving over at least 2 ft of soil or gravel 0.5
Enhanced tree growth systems 0.4
Renewable energy generation (area of) 0.5
Bonuses
Native plant species 0.1
Landscaping in food cultivation 0.1
Graphic courtesy Laine Cidlowski
31. Green Area Ratio: How Does it Work?
How to calculate:
Add up landscape elements by
number or size
# trees
Size of green roof
Size of rain garden
# of plants
Soil depths
Divide by lot area
= GAR score
Graphic courtesy Laine Cidlowski
32. What would we need to do to get a higher Green Area
Ratio? At minimum….
Revise ordinances to
eliminate barriers:
Landscaping
Screening
Setbacks
Open Space
Right-of-Way
Evaluate/select practices
we want to encourage
32
33. What would we need to do to get a higher Green Area
Ratio? Being more proactive..
Evaluate the “ratio” we want in different zones
Existing green area ratio by town districts/zones
Cost sensitivity
Provide incentives or requirements to meet Green
Area Ratio
Cost of Green Area Ratio requirements in dense
urban areas (Seattle, Washington D.C.)
Typically 0.5% of total construction costs
Consistently less than 1.0% of total construction costs
33
34. Greenprinting – Three Types
Site Design Based
Enhanced green features
Land Conservation Based
Natural heritage sites, trails, open
space, parks, community gardens,
farmland preservation
Sustainable Development Based
Open space, water resources,
urban design, energy, materials,
transportation
34
37. Greener Infrastructure - Triple Bottom Line Benefits
Job Creation
Jobs for skilled and unskilled workers
Present worth of reduction in social costs
Reduced Infrastructure Costs
38. Greener Infrastructure - Triple Bottom Line Benefits
Increased Property Values
Median 4% increase
Increased Recreational Opportunities
39. Greener Infrastructure - Triple Bottom Line Benefits
Carbon Sequestration Offsetting
Annual carbon emissions from autos or
Single family homes
Reduced Energy Use
Reduction of kWh in energy use and energy savings
40. Greener Infrastructure - Triple Bottom Line Benefits
Load Reductions and Runoff Benefits
TSS removed per year
Reduction in runoff
Groundwater recharge
41. (1) Address uncontrolled runoff from existing development
(2) Be realistic about what can be achieved
(3) Build on our strong stormwater performance standards
(4) Consider new incentives/requirements for green practices
(5) Select practices that provide multiple benefits
February 11, 2012
42. Triple Bottom Line Analysis – Other Benefits
Amenity and comfort ratings are ______% higher for a
tree-lined sidewalk compared to a non-shaded street.
20%
60%
80%
43. Triple Bottom Line Analysis – Other Benefits
Amenity and comfort ratings are ______% higher for a
tree-lined sidewalk compared to a non-shaded street.
20%
60%
80%
44. Triple Bottom Line Analysis - Other Benefits
Desk workers who can see nature from their desks
experience approx ___% less time off sick.
10%
25%
45%
45. Triple Bottom Line Analysis - Other Benefits
Desk workers who can see nature from their desks
experience approx ___% less time off sick.
10%
25%
45%
46. Triple Bottom Line Analysis - Other Benefits
Study of green space amenity values related to
customers’ price valuation, participants priced goods
____% higher in landscaped districts.
3%
9%
12%
47. Triple Bottom Line Analysis - Other Benefits
Study of green space amenity values related to
customers’ price valuation, participants priced goods
____% higher in landscaped districts.
3%
9%
12%
48. Triple Bottom Line Analysis - Other Benefits
Survey of one community, _____% of the public
preferred to patronize commercial establishments
whose structures and parking lots have trees and
landscaping.
50%
75%
100%
49. Triple Bottom Line Analysis - Other Benefits
Survey of one community, _____% of the public
preferred to patronize commercial establishments
whose structures and parking lots have trees and
landscaping.
50%
75%
100%
50. Triple Bottom Line Analysis - Other Benefits
People make more walking trips when they are aware
of natural features, and judge distances to be greater
than they actually are in less green neighborhoods.
True
False
51. Triple Bottom Line Analysis - Other Benefits
People make more walking trips when they are aware
of natural features, and judge distances to be greater
than they actually are in less green neighborhoods.
True
False
Editor's Notes
Provides a menu of landscape elements and establishes a minimum score for new development.In addition to conventional landscape elements, menu includes green roofs, vegetated walls, pervious paving, and bonuses for public visibilityIncreases the amount of landscaping required, while also increasing design flexibilityIncrease the amount and quality of urban landscaping in dense urban areas while allowing increased flexibility for developers and designers to efficiently use their properties:Builds on DDOE stormwater requirementsApplicable to low & moderate density zonesFlexibleConsistentHigher environmental valueProvides targets based on relative level of urbanism