The document discusses ways to improve stream stewardship in the communities of Chapel Hill, Carrboro, and Orange County, North Carolina. It notes several things the communities are doing well related to stormwater management and environmental protection. It then discusses the need to address runoff from existing development, have realistic expectations for stream restoration, build on strong stormwater standards, provide incentives for green practices, and select practices that provide multiple benefits. Finally, it provides examples of potential projects and policies to help meet these goals, such as retrofitting neighborhoods, streets, and public/private properties with green infrastructure to reduce runoff, and implementing innovative approaches like stormwater utilities, trading programs, and cost-sharing to fund the work.

1. Stream Stewardship
What we’re doing well.
Ideas from other
communities.
Kimberly Brewer, AICP
February 11, 2012

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

4. Watershed Improvement-
Getting at the Existing
Impairment of Our Streams

5. Development Impacts: Runoff Volume
Typical pre-development Typical post-development
conditions: conditions:
Runoff = 10% Runoff = 55%
Infiltration = 50% Infiltration = 15%

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

10. Neighborhood Streets Retrofits
10

11. Green practices aren’t just pretty gardens….
Dry Well Vegetated Swale Bioretention Area or Raingarden
11

12. Downtown Streetscape Retrofits
12

13. DOT Highway Retrofits
13

14. Public Property Retrofits
School micromanaging
stormwater throughout the site.
Park stormwater detention basin
also serving as playing field.
14

15. Private Property Retrofits
15

16. Look around. You’ll see lots of retrofit opportunities…
16

17. Other Ideas
 Downspout Disconnect
Programs
 Better Sewer Easement
Maintenance
17

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

22. Watershed Protection-
Performance Standards for
New Development

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

27. HOW We’re Meeting
Performance Standards-
Ideas for Greener Approaches

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

35. High Quality Green Area: Which do we want to encourage?
35

36. Healthy environment
Healthy economy
Healthy community
Triple Bottom Line

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