Zoning for Sustainability: Green Area Ratio for Sustainability: Green Area Ratio September 27, 2011...
Transcript of Zoning for Sustainability: Green Area Ratio for Sustainability: Green Area Ratio September 27, 2011...
Zoning for Sustainability: Green Area Ratio
September 27, 2011
Laine Cidlowski, AICP, LEED AP
District of Columbia Office of Planning
Zoning Review Process
OP Goals for Zoning Review:
Clarity
Relevance
Ease of use
Zoning Review Process: Subject Areas
Policy Procedural
• Low/Mod Density – Res.
• Industrial
• Campus/Institutional
• Downtown
• Parks/Open Space
• Med/High Density
• Commercial Corridors
Mixed/Other (Waterfronts)
• Planned Unit Development (PUD)
• Design Review
• Administration/ Enforcement
• ZC & BZA Procedures
Land UseLand Use
• Floodplain• Height• Parking• Loading• Arts & Culture• Retail• Historic Structures• Sustainability
Sustainability RecommendationsA. Integrating Land Use and Mobility
B. Energy Conservation and Renewable Energy
C. Water and Sensitive Resource Protection
D. Food Security
E. Green Jobs
F. Large Area Development
Water and Sensitive Resources
5 Major Topics
Promote Water Conservation Protect and Enhance Tree Cover Reduce Runoff and Soil Erosion Provide Buffers for
Environmentally Sensitive Areas Protect Floodplains
Water ConservationRain Harvesting Devices Explicitly permit Allow in yard setbacks,
underground and on rooftops
Vegetated roofs Exempt from rooftop
setbacks Encourage through site
design requirements Updated building code
likely to require “cool” roofs
Tree Cover Protection
Expand tree cover protection
Study applying TSP overlay to residential zones citywide
Potential Guides Lower trigger to 25”
circumference (or equivalent dbh)
Allow tree removal subject to replacement of equivalent carbon absorption
Consult with Urban Forestry Administration (UFA)
10
Water ConservationLow-Water Use
Landscaping Specify native and low-
water demand species and encourage their use
Encourage through site design requirements
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Reducing Runoff/ErosionParking Lot
Landscaping Require design and
distribution of landscaped areas to reduce/filter runoff (e.g., minimum planting bed size)
Encourage pervious pavement through site design requirements
Encouraging Green Site Design Water Recommendations Encouraged: Green/cool roofs Pervious surfaces Native/water conserving landscaping Tree planting/preservation
These can be addressed comprehensively through site design requirements
Green Area Ratio provides flexible, consistent regulation of environmental site design
Best Practices: Other Cities Berlin, Germany: Biotope Area Factor Seattle, WA: Green Factor Required for all new development in neighborhood business
districts with more than four dwelling units, more than 4,000 square feet of commercial uses, or more than 20 new parking spaces
Goal: Increase the amount, quality of urban landscaping in dense areas while allowing flexibility for developers and designers to use property efficiently
Fife, WA: Fife Green Factor
Seattle’s Green Factor
A landscape requirement that values both the aesthetic and ecological functions of planted areas.
Raises the bar for total landscaped area, but awards credit to new types of features.
Adopted for Commercial zones as part of the Neighborhood Business District Strategy in 2006, implemented Jan 20, 2007
DC’s Green Area RatioWhat is it? A flexible green site design
requirement that varies by building type
How Achieve? Choose from a range of
environmental landscaping practices each of which have been assigned an environmental performance ranking
Examples may include… Turf grass
Un-vegetated permeable pavement
Vegetated permeable pavement
Green roofs
Natural ground cover
Rain gardens
Trees & shrubs
Vegetated walls
GAR: 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
Green Area Ratio Benefits• 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
GAR: Recommendations to Reality Sample sites for proof of
concept testing by zone and building type
Costing estimates for proof of concept testing
Discussions with DCRA, DDOE, DDOT
Many decisions on program details
Detailed Decisions Where will it apply What will the
environmental multipliers be
What landscape elements will be included
By whom will the projects be certified
GAR Sample Scoresheet Landscape elements Allowed to double count
plant and soil depth Different values for
different size plants Includes permeable paving Includes green roofs Includes bonus for native
plants Bonuses for food
cultivation
1300. Introduction to GAR regulation Explains what the GAR is “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. “
Explains why the GAR is being implemented Achieve environmental performance Meet city-wide environmental goals
1302. Applicability of GAR Standards Applies to all new buildings requiring a C of O i.e. no single family homes
Does not apply to R-1 to R-4 zones Applies to all renovations over 100%
assessed value Will not apply in public space
Will apply different GAR scores in different zones
1303. Calculation of GAR Info used to calculate GAR Landscape element options, and GAR values How to measure landscape elements Sf equivalencies for plants & trees Technical calculation of GAR
GREEN AREA RATIO LANDSCAPE ELEMENTS MULTIPLIERLandscaped area (select one of the following for each area)Landscaped areas with a soil depth of less than 24 in. 0.3Landscaped areas with a soil depth of 24 in. or more 0.6Bioretention facilities 0.4PlantingsGround covers, or other plants less than 2 ft tall at maturity 0.2Plants at least 2 ft tall at maturity 0.3Tree canopy for all trees 2.5 in. to 6 in. in diameter 0.5Tree 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 0.8Vegetated wall, plantings on a vertical surface 0.6Vegetated roofsExtensive 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 0.8Water features (using at least 50% recycled water) 0.2Permeable pavingPermeable paving over at least 6 in. and less than 2 ft of soil or gravel 0.4Permeable paving over at least 2 ft of soil or gravel 0.5Enhanced tree growth systems 0.4Renewable energy generation (area of) 0.5BonusesNative plant species 0.1Landscaping in food cultivation 0.1
1304. Landscape element eligibility conditions for GAR Bioretention = rain gardens, includes Baysavers Trees Vegetated walls – further specifics on how to
measure Vegetated roofs
1304. Landscape element eligibility conditions for GAR Water features Enhanced tree growth Native plant species Food cultivation Stormwater irrigation
1305. Submittal Requirements for GAR 1305.2 Requires certified landscape experts Submit landscape plan with typical elements Flexibility for weather, seasons, reasonable changes 1305.2 Certified landscape experts rely on MD and VA programs
1306. Special Exception for GAR Allow flexibility for our historic sustainable fabric Recommendation – Calibrate by zone
1307. Maintenance Requirements for GAR To ensure that environmental performance is achieved
Case Study : High Density Multi-family Residential: 900 G Street NE
Zone: R-5-D
Existing GAR = 0.18
Paved areas to permeable paving + trees = 0.36
Above + ½ green roof =0.488
All of Above + raingarden = ≥ 0.5
G ST NE
9TH
ST
NE
PIC
KFO
RD
PL
NE
Lot 08030650 10TH ST NE
Lot 08310656 9TH ST NE
Lot 08320654 9TH ST NE
Lot 08290813 G ST NELot 0827
0651 8TH ST NE
Lot 00570900 G ST NE
Lot 00550901 H ST NE
Lot 00800910 G ST NE
Lot 00690800 G ST NE
Lot 01600811 G ST NE
Lot 01590809 G ST NE
Lot 00700718 10TH ST NE
Lot 00720714 10TH ST NE
Lot 00760706 10TH ST NE
Lot 00740710 10TH ST NE
Lot 00780702 10TH ST NE
Lot 00710716 10TH ST NE
Lot 00790700 10TH ST NE
Lot 00730712 10TH ST NE
Lot 00770704 10TH ST NE
Lot 00750708 10TH ST NE
Lot 00590719 8TH ST NE
Lot 00630711 8TH ST NE
Lot 00610715 8TH ST NE
Lot 00680701 8TH ST NE
Lot 00600717 8TH ST NE
Lot 00670703 8TH ST NE
Lot 00650707 8TH ST NE
Lot 00640709 8TH ST NE
Lot 00620713 8TH ST NE
Lot 00660705 8TH ST NE
Case Study: 100% Lot Occupancy Downtown 800 17th Street NW
Zone: C-4
Existing GAR = 0.30
Low green roof = 0.30
Thicker green roof instead = 0.40
Low green roof + renewable energy generation = 0.56 max
Case Study: Small scale Commercial: 1443 Howard Road SE Zone: C-1 Existing GAR = 0.0 ½ roof with thick green roof
= 0.1 ≤ 1/2 the paving to
permeable = 0.1 All pavement permeable+
plants and trees = 0.26 Permeable paving +
raingarden + plants + green roof = 0.37
Green Area Ratio: Where is it in Process? Developed from
Sustainability Working group
Preliminary text approval from Zoning Commission
Administrative process & responsibilities
Finalize city-wide research to determine GAR for all zones
Next Steps Interagency Admin group Set GAR for all zones Implement!
GAR: Long Term Steps Training of Program administrators, inspectors Develop educational materials and training for developers
and the public Step by Step instructions Webinars Sample implementation Etc.
Establish tracking system for projects Obtain funding for interactive online weighting tools or
‘find a BMP’ databases
Contact Questions?
Laine Cidlowski, District of Columbia Office of Planning Urban Sustainability Planner AICP, LEED AP [email protected]