HOW CREEKS (should) AFFECT DEVELOPMENT
Clark Wilson, Community Design + ArchitectureSCVURPPP Workshop December 7, 2005
“Stormwater is not a mechanical system. It is an environmental process, joining the atmosphere, the soil, vegetation, land use,and streams, and sustaining landscapes.”
Bruce K. Ferguson
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What Is “Green” Community Design?
Smart Growth Principles
1. Increased Density 2. Transit and Pedestrian
Accessibility 3. Infill and Brownfield
Development4. Bridging Institutional
Barriers
Green Infrastructure for Water Quality 1. Non-mechanical treatment
of storm water run-off2. Landscape for detention and
detention3. Maximizing water reuse
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Goals for Green Community Design
Livability1. Improve Water Quality2. Use Land Efficiently3. Embrace Natural Processes4. Provide Cost Effective Solutions5. Create Unique and Attractive Communities and
Neighborhoods
A Watershed Strategy to Community Design
5. Erosion and Sediment ControlMitigate the impacts of erosion and
sediment discharge
6. Stormwater Treatment PracticesIntegration of structural design
solutions
7. Non-stormwater dischargesSeptic and sanitary sewer spill
prevention
8. Watershed Stewardship ProgramsNecessary to increase public
understanding and awareness
1. Land Use PlanningDeveloping land-use pattern at
a sub-watershed scale to meet water resource goals
2. Land ConservationConsider value of existing
aquatic resources both cultural and ecological
3. Aquatic BuffersProtect streams, wetlands and
natural floodplains
4. Better Site DesignReducing impacts at the site
level
Concepts
Thinking About Watersheds
The Hydrologic Cycle and the Effects of Urbanization
Brownfield Conditions
Integrating Solutions
Development Types and Associated Runoff Volumes
Integrating Solutions: Solving Multiple Issues
1. Stormwater
2. Parking
3. Recreation + Green Space
4. Pedestrian Amenities
5. Multi-modal Streets
6. Habitat Protection + Creation
7. Energy Efficiency
8. Visual Interest
Integrating SolutionsSo
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Green Stormwater Treatment & Management
Pedestrian and Bicycle Amenities
Convenient Parking
Aesthetic Benefits
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EcoTrust Parking Lot, Portland OR
Green Infrastructurethe Metro Portland Green Streets Projectthe Metro Portland Green Streets Project
Green StreetsSteering Committee
1. Federal Fisheries & EPA
2. State Fish & Game, DoT, & Environmental
3. Metro Regional Transportation Staff
4. County Public Works & Planning
5. City Transportation & Planning
6. Environmentalists
7. Developers
8. Bicycle Advocates
Detention Basins/Wetponds
A permanent pool of water that detains and treats runoff
Water follows a path of pools created by including jetties and islands
Provides ecological habitat (including mosquito-eating predator species)
Design as amenity - not a hazard!
Detention Basins - Linear
Linear drainage basins provides temporary storage, attenuates flow and allows some infiltration
Incorporate into road r.o.w and other “leftover” spaces
Aesthetic designs include stone "walls" and vegetative covers
Infiltration
• Infiltration Basins• Similar concept to Rain
Gardens
• A range of scales depending upon context
Infiltration Basin Plan
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Infiltration Basin with Parking
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Infiltration Basin with Parking
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Bio-Filtration - Swales
School Parking Lot, Portland OR
Swale, Cross Section
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• Required slope >1% but < 5%• Over 3%, use check-dams • Side slopes should not exceed
1:3• Broad range of plant types
appropriate/preferred• Curb treatments can be flexible,
but intake must be controlled• Allow appropriate “residence
time” for water to be in contact with vegetation - typical length >120 feet
• No ponding longer than 48 hours• For clay soils, use amended soils
or underdrains
Mid to High Density Design Solutions
Tree Preservation and Planting
Permeable and Pourous Paving
Infiltration
Bio-Retention
Bio-Filtration
Tree Preservation and Planting
• Stormwater Functions
• Intercept and hold large quantities of rainwater on the leaf surfaces
• Absorb and transpire large quantities of ground water
• Remove pollutants from stormwater and stabilize them
• Canopies shade and cool paved areas, reduce heat pollution
Structural Soils
• Artificial growing medium encourages root growth and satisfies pavement requirements
• Gap graded gravels: crushed stone, clay loam, and a hydrogel stabilizing agent
• Work well on remediated sites that require new fill
• Ideal for trees in parking lots, sidewalks, and other constrained spaces
Structural Soils, Cross Section
Permeable and Pourous Paving
• Reduces amount of impervious surface
• Appropriate for low-speed locations
• Installation is key
• ADA issues
• Limited applicability in brownfield conditions due to soils and ground water
Alameda
Grass Pavers, Havana, Cuba
Bio-Retention
Street Tree Wells
1. Appropriate for urban streetscapes
2. Use structural soils to provide sub-surface planting trench
3. Provide better environment for street trees
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Permeable Paving - Example Project
SE 20th & 21st Avenues between Knapp & LambertPortland, OR
Designer: Steven Berger, P.E. City of Portland Bureau of Environmental Services
Permeable Paving - Example Project
SE 20th & 21st Avenues between Knapp & LambertPortland, OR
Designer: Steven Berger, P.E. City of Portland Bureau of Environmental Services
Permeable Paving - Example Project
SE 20th & 21st Avenues between Knapp & LambertPortland, OR
Designer: Steven Berger, P.E. City of Portland Bureau of Environmental Services
Bio-retention - Example Project
“New Seasons” Street PlantersSE 20th and Division, Portland, OR
Designer: Kevin Perry, City of Portland Bureau of Environmental Services
Bio-retention - Example Project
“New Seasons” Street PlantersSE 20th and Division, Portland, OR
Designer: Steven Berger, P.E. City of Portland Bureau of Environmental Services
Bio-retention - Example Project
“New Seasons” Street PlantersSE 20th and Division, Portland, OR
Designer: Kevin Perry, City of Portland Bureau of Environmental Services
Bio-filtration - Example Project
NE35th & Siskiyou Street Filter Strips Project,Portland, OR
NE Siskiyou Street
NE
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NE 36 thAvenue
Designer: Kevin Perry, City of Portland Bureau of Environmental Services
Bio-filtration - Example Project
NE35th & Siskiyou Street Filter Strips Project,Portland, OR
Designer: Kevin Perry, City of Portland Bureau of Environmental Services
Bio-filtration - Example Project
NE35th & Siskiyou Street Filter Strips Project,Portland, OR
Designer: Kevin Perry, City of Portland Bureau of Environmental Services
Bio-filtration - Example Project
NE35th & Siskiyou Street Filter Strips Project,Portland, OR
Designer: Kevin Perry, City of Portland Bureau of Environmental Services
Bio-filtration - Example Project
NE35th & Siskiyou Street Filter Strips Project,Portland, OR
Designer: Kevin Perry, City of Portland Bureau of Environmental Services
Parking Strategies
What is the Link between Parking and Stormwater runoff?
1. Reducing Impervious Surface
2. Incorporate Stormwater Systems into Parking
3. Increased Development Potential of Dense Green Infill
Source: N\N & CD+A
Shared Parking for Mixed-use Districts
Structured or Stacked Parking
1. Encourage parking structures (with design controls), or other vertical parking strategies like valet and parking lifts
2. Guide Design -Greens stormwater treatments,
Control curb cuts, blank walls, and other design controls
Source: N\N & CD+A
Green Roofs
Gap Corporate headquarters, San Bruno, CA
Extensive Green Roof Cross Section
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Extensive Green Roofs
1. Bio-Filtration, evapotranspiration- can intercept 10 to 100% of the rain that falls on them
2. Light, thin layer of planting medium and vegetation
3. Maintenance is minimal but key-especially during plant establishment period
4. Not intended for frequent access
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American Motors Corporate Headquarters, Irvine
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Extensive Green Roofs
1. Create savings through reduced energy demand
2. Provide bird and insect habitat
3. Provide aesthetic value and benefits
4. Feasible on contaminated sites
5. Potentially feasible for retrofit projects
c.
Green Roofs
Oakland Museum Garden Terraces, Oakland, CA
Kaiser Parking Garage, 5th Level Roof Garden, Oakland, CA
Intensive Green Roofs
1. Bio-filtration, evapotranspiration of runoff
2. Public or private access to gardens, open space or recreation facilities
3. Feasible on contaminated sites
4. Higher economic/structural demands- less suitable for retrofit projects
Green Roofs
Infiltration
Pima Community College, Tucson, AZ
• Infiltration Trenches
• Collect storm water and slowly infiltrate or attenuate
• Can employ filtering devices to pre-treat storm water
• Can connect to existing storm sewer system
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Infiltration System, Portland, OR
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CBF Merrill Environmental Center, Annapolis, MD
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Cisterns
1. Collect rainwater from roof and store it for irrigation and other non-potable uses
2. Attenuate peak runoff flows
3. Conserve potable water resources
4. Cisterns can be located above or below ground
5. System should include a “roof washer” or “first flush” device
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Water Storage and Harvesting
Cistern Detail
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BES Water Pollution Control Lab, Portland, OR
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Rain Gardens
1. Utilize soil, plants, trees, hardscape elements to support and enhance infiltration and bioremediation
2. Proven method of bio-remediation.
3. A broad range of plant types can be appropriate and are preferred
4. Can provide habitat and aesthetic value
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Bio-Retention
Buckman Heights Apartments, Portland, OR
Drip-line Planter, Cross Section
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City
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Port
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Drip-Line Planters
1. Suitable for contaminated Sites- planter prevents exfiltration to underlying soils
2. Feasible for sites with space constraints
3. Feasible for retrofit projects
4. Should include a “roof washer” or “first flush” device
Bio-Retention
Bio-Filtration
• Swales
• Swale bottom to be at least 4-6 ft. wide
• Side slopes should not exceed 1:3
• Avoid erosion - use cobbles and no V-ditches
• Use rough calculation of 1200 sq.ft.of usable swale per acre of impervious surface (“Start at the Source”)
• Inspect, mow and water
• Resource: Darren Greenwood Public Services, Water Resources, City of Livermore
Parking Lot, Livermore, CA
Phoenix Office Complex with Rain Catchers
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“Sun Flower” Shades, Palo Alto, CA
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Rain Catchers
1. Intercept rainfall for storage and harvesting
2. Unique urban design elements--lend visual character and identity
Sun Shades
1. Shade sidewalks, reduce heat pollution in runoff
2. Provide pedestrian amenity
3. Create visual interest
Other Devices and Programs
Selecting and Sizing Design Solutions
Combined Solutions:
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AA. Green Roof
B. Cisterns
C. Rainwater garden with drip line
D. Drip-line planter
E. Bio-retention tree well
F. Infiltration basin
Selecting and Sizing Design Solutions
Design Considerations1. Opportunities to reduce
impervious surface coverage:
reduce surface parking?reduce building footprints?
2. Can passive or intensive green roofs be integrated into design?
3. Can turf be irrigated with captured rainwater? Or replaced with rain gardens?
4. Can pervious paving be used as a hardscape material?
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“I never learned to doubt that the city was part of nature…Cities must resist the habit of fragmenting nature.
Only by viewing the entire natural environment as one interacting system can
the value of nature be fully appreciated.”
Anne Whiston Spirn