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Kimberly Brewer Tetratech: Stream Stewardship
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Kimberly Brewer Tetratech: Stream Stewardship

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  • 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 visibility Increases the amount of landscaping required, while also increasing design flexibility Increase 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 requirements Applicable to low & moderate density zones Flexible Consistent Higher environmental value Provides targets based on relative level of urbanism
  • Tools to Meet the Challenge
  • Tools to Meet the Challenge
  • Tools to Meet the Challenge
  • Tools to Meet the Challenge
  • Transcript

    • 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.
    • 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 conditions: Runoff = 10% Infiltration = 50% Typical post-development conditions: Runoff = 55% Infiltration = 15%
    • 6. Development Impacts: Overland Pollutant Loading
    • 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
    • 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.
    • 9.
      • How can we proactively reduce impacts from existing development?
    • 10. Neighborhood Streets Retrofits
    • 11. Green practices aren’t just pretty gardens…. Dry Well Vegetated Swale Bioretention Area or Raingarden
    • 12. Downtown Streetscape Retrofits
    • 13. DOT Highway Retrofits
    • 14. Public Property Retrofits School micromanaging stormwater throughout the site. Park stormwater detention basin also serving as playing field.
    • 15. Private Property Retrofits
    • 16. Look around. You’ll see lots of retrofit opportunities…
    • 17. Other Ideas
      • Downspout Disconnect Programs
      • Better Sewer Easement Maintenance
    • 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)
    • 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.
    • 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
    • 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
    • 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.
    • 24. Changes in Flow
    • 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.
    • 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
    • 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”. 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
    • 30. Graphic courtesy Laine Cidlowski 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
    • 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
    • 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
    • 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
    • 35. High Quality Green Area: Which do we want to encourage?
    • 36. Healthy environment Healthy economy Healthy community Triple Bottom Line
    • 37.
      • Job Creation
        • Jobs for skilled and unskilled workers
        • Present worth of reduction in social costs
      • Reduced Infrastructure Costs
      Greener Infrastructure - Triple Bottom Line Benefits
    • 38.
      • Increased Property Values
        • Median 4% increase
      • Increased Recreational Opportunities
      Greener Infrastructure - Triple Bottom Line Benefits
    • 39.
      • Carbon Sequestration Offsetting
        • Annual carbon emissions from autos or
        • Single family homes
      • Reduced Energy Use
        • Reduction of kWh in energy use and energy savings
      Greener Infrastructure - Triple Bottom Line Benefits
    • 40.
      • Load Reductions and Runoff Benefits
        • TSS removed per year
        • Reduction in runoff
      • Groundwater recharge
      Greener Infrastructure - Triple Bottom Line Benefits
    • 41. February 11, 2012 (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