urban water quality issues - green design & development
DESCRIPTION
Dwane JonesTRANSCRIPT
Introduction:
What is “Green Design & Development?”
Green Design & Development
http://www.bae.ncsu.edu/topic/lid/
Working Definition
Green Building and Development is environmental responsiveness. It is integrating water quality, and air
quality concepts with building technology.
Green Design & Development
Source: USGBC
Source: USGBC
Source: USGBC
Source: USGBC
Source: USGBC
Source: USGBC
Source: USGBC
Daylighting
Solar Panels
Green Roof
Bike Paths
Biodiesel/Other Fuels
BicyclesWater Harvesting
Multi-Use Recycling Efficient Lighting
Natural Air Flow
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Source: USGBC
Source: USGBC
Green Planning
Green Design & Development
http://www.bae.ncsu.edu/topic/lid/
Conventional land development involves removal of all vegetation, compacting the soil and putting in large areas of hard (impervious) surfaces like roads, parking lots and roofs. The compacted soil and impervious surfaces prevent stormwater from soaking into the ground (called infiltration). This results in a tremendous increase in surface runoff.
By traveling much faster, stormwater runoff overwhelms streams causing flooding, damaging public and private property and destroying habitat for fish and wildlife.
Further, conventional practices collect and convey stormwater runoff through storm drains and pipes to a centralized, manmade stormwater facility to manage stormwater flow and remove pollutants.
This typically requires extensive use of pipes and sometimes large, costly, stormwater best management practices.
•Natural areas
•Smaller lawns
•Better pedestrian access
•Wildlife Habitat
•Open Space
• Wooded Lots
Modern Trend: Homebuyers
Forsyth County
July 2006- 331,859
April 2000- 306,044
+ 25,815
(most recent census)
Growth Trends: North Carolina
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http://www.bae.ncsu.edu/topic/lid/
Design, construct, & maintain each development site to protect, or restore, the natural hydrology (the scientific study of the properties, distribution, and effects of water on the earth's surface) of the site so that the overall integrity of the watershed is protected. This is done by creating a “hydrologically” functional landscape.
-Minimize land clearing
- Amended Soils
-Minimize use of impervious surfaces
-Infiltration
-Natural hydrology
-Removal of most or all vegetation
-Soil Compaction
-Use of large amounts of impervious surfaces
-Costly infrastructure
-Altered hydrology
LIDPRACTICE /
DEVICEPeak Flow Control Volume Reduction
Water Quality Improvement
Water Conservation
Bio-retention Cell • • •
Cistern • • ~~> • <~~ •
Curbless Parking Lot Islands
• • •
Downspout Disconnection • • •
Grassed Swale • • •
Green Roof • •
Infiltration Trench • • •
Narrow Road Design • • •
Permeable Pavers/Pavement
• • •
Rain Barrel • • •
Rain Garden • • •
Sand Filter • •
Tree Box Filter • •
Tree Planting • •
LID Subdivision
Low Impact Development
1.Mix land uses.
2.Compact building design.
3.Diverse housing opportunities.
4.Walkable neighborhoods.
5.Distinctive, attractive communities.
6.Preserve open space, farmland, natural beauty, and critical environmental areas.
7. Reinvest in and strengthen existing communities and achieve more balanced regional development.
8. Provide a variety of transportation options.
9. Make development fair, predictable, and cost-effective.
10. Encourage stakeholder participation.
-Perspectives (Designer, Developer, Governing Authority)
-*Local Ordinances & Site Plan Review Process (often antiquated)
*The developer may request a variance, but often these can be time-consuming.
-Local Opposition from Governing Body
-Minimize risks
-Satisfy client
-Utilize accepted practices
-Gain respect from governing authority
-Minimize financial risk
-Maximize Profit
-Minimize Time (permitting etc.)
-Maximize value
-Minimize surprises
-Satisfy clients/customers
Designer Developer
-Minimize risks
-Minimize short-range and long-range government expenses
-Enforce environmental regulations
-Performance of Practices
Local Government
-Protection of Landowners
Green Construction (Land)
Green Design & Development
•Using narrower, shorter streets and ROW
•Smaller lots and setbacks, narrow frontages
•Reducing the amount of residential lawns
•Spreading stormwater runoff over pervious areas
•Using open channels instead of curbs/gutters
Site Design
-Identify Buildable & Non-buildable areas*
-Annual Rainfall Data*
-Topography*
-Soils*
-Zoning/Public Input*
-Floodplain/Floodway*
-Land Uses/Adjacent Land Uses*
-Access/Egress
-Easements
-Costs
-Lot Orientation
-Infrastructure Technologies/Techniques*
-Aesthetics
-Topography
-Potential Hydric Soils
-Streams/Water Bodies
www.terraserver.com
-Help determine placement of streets, lots, buildings etc.
-US Army Corps of Engineers & DWQ
-Consider sheetflow
-Shallow depressions (during rainy seasons)
http://www.bae.ncsu.edu/topic/lid/
-US Army Corps of Engineers & DWQ
-Note: Each acre of coastal wetland contributes from $800 to $9,000 to the local economy through flood protection and recreation such as bird watching, fishing, and boating (Kirby, 1993)
Design Practices: -Minimize construction in wetlands by building compact developments-Plan roads and utilities to cross at the narrowest point in the system-Use permeable pavement for access roads, trails, and overflow parking-Preserve contiguous riparian buffers along wetlands and wildlife habitat-Create wetlands that mimic natural hydrological processes
Source: Green Growth Guidelines
www.bae.ncsu.edu/stormwater
Soil Survey
-Infiltration
-Federal Emergency Management Agency (FEMA)
-National Flood Insurance Program (NFIP)
www.ncfloodmaps.com
-Moderate Temperatures
-Wind Buffers
-Reduce stormwater volumes
-Minimize Erosion
Note: Research shows that nearly 60% of suburban residents actively engage in wildlife watching…the majority is willing to pay a premium for homes in these settings (Adams, 1994)
Design Practices: -Keep the width & length of stream crossings at a minimum-Use existing crossings when possible-Use bottomless culverts beneath road crossings for fish passage-Preserve contiguous buffers-Use LID integrated management practices-Use natural streambank stabilization practices-Avoid or minimize alteration to natural stream flow Source: Green
Growth Guidelines
Design Practices: -Avoid or minimize the placement of infrastructure in the buffer zones-Avoid or minimize multiple crossings-Use native vegetated buffers, when possible
Source: Green Growth
Guidelines
-Wildlife Resources Commission
-Non-profits
-National Register of Historic Places
Design Practices: -Base design on average daily traffic-Provide safe and efficient access for emergency vehicles-Use minimum design requirements (LID)-On-street parking lanes should serve as traffic lanes-Urban Streets with parking on both sides (rec: 32’)-Neighborhood street with parking on one side (rec: 24’)-Local street width (rec: 18’)-Cost savings, pedestrian safety, and reduction in impervious coverSource: Green Growth Guidelines
The amount of impervious surface created by cul-de-sacs can be reduced by creating a pervious island in the center
Source: The News Magazine of the Federated Conservationists of Westchester County, http://www.fcwc.org/WEArchive/010203/roofs.htm
Photos courtesy of Whitney Kurz
Green Building (Home/Structure)
Green Design & Development
Integrating Green Design with Low Impact Development &
Conservation Design
Green Design & Development
•Capturing roof runoff
•Disconnecting pavement and roof drainage
•Infiltration Practices/Planting trees
•Rehabilitating soils
•Reconfiguring driveways, parking lots, and streets
Comprehensive Design
•Use of permeable pavements
•Routing runoff through swales to slow velocity, remove pollutants, & infiltrate
•Restoring “daylighting” historic streams to enhance naturalized open channels
Comprehensive Design
http://www.bae.ncsu.edu/topic/lid/
• Filtering system designed for evapotranspiration & infiltration
• Useful for parking lot runoff
• Economical for small sites
•Useful for removing:
-Suspended solids, hydrocarbons, certain metals, and nutrients
BioretentionTreatment, Retention, Infiltration, Landscaping
BioretentionTreatment, Retention, Infiltration, Landscaping
• Excavation filled with engineered soil mix
• Herbaceous perennials, shrubs, trees
• Ponded water infiltrates within 72 hours
• Overflow outlet and optional underdrain
• Excavation filled with engineered soil mix
• Herbaceous perennials, shrubs, trees
• Ponded water infiltrates within 72 hours
• Overflow outlet and optional underdrain
Source: CWPSource: Massachusetts LID Toolkit
BioretentionApplicationsBioretentionApplications
• Parking lot islands
• Median strips
• Residential lots
• Office parks
• Parking lot islands
• Median strips
• Residential lots
• Office parks Source: Larry Gavin
Source: LID CenterSource: City of Portland, OR
Source: Massachusetts LID Toolkit
Bioretention AreaSmall parking lots
Bioretention AreaSmall parking lots
Source: Massachusetts LID Toolkit
Stormwater PlantersRunoff Reduction, Treatment, Attenuation
Stormwater PlantersRunoff Reduction, Treatment, Attenuation
• “Bioretention in a Box”
• Vegetative uptake of stormwater pollutants
• Pretreatment for suspended solids
• Aesthetically pleasing
• Reduction of peak discharge rate
• “Bioretention in a Box”
• Vegetative uptake of stormwater pollutants
• Pretreatment for suspended solids
• Aesthetically pleasing
• Reduction of peak discharge rate
Source: City of Portland, OR
Source: City of Portland, OR
Source: Massachusetts LID Toolkit
http://www.bae.ncsu.edu/topic/lid/
www.bae.ncsu.edu/stormwater
Retrofit Opportunities
• Water quantity benefits
• Indirect water quality benefits
• Infiltration
Permeable PavingApplications
Permeable PavingApplications
• Parking stalls
• Overflow parking
• Driveways
• Walkways and plazas
• Parking stalls
• Overflow parking
• Driveways
• Walkways and plazas
Photo Copyright 1999, Center for Watershed Protection
Downspouts Connected to Driveway = More Runoff, Less Infiltration
Source: CWP Source: Massachusetts Smart Growth Toolkit
www.bae.ncsu.edu/stormwater
• Increased insulation
•Decreased heat island effect
•Decreased stormwater volumes and rates
•Decreased long-term replacement costs
•Increased property value
•Downsizing HVAC
www.bae.ncsu.edu/stormwater
Conventional Low Impact
Functional Landscape DesignGood DrainageConventional
Small-scale Controls
street width
treescape
runoff
Vegetated SwalesConveyance, Treatment, InfiltrationVegetated SwalesConveyance, Treatment, Infiltration
• Roadside swales (country drainage) for lower density and small-scale projects;
• For small parking lots;
• Mild side slopes and flat longitudinal slopes;
• Provides area for snow storage & snowmelt
treatment
• Roadside swales (country drainage) for lower density and small-scale projects;
• For small parking lots;
• Mild side slopes and flat longitudinal slopes;
• Provides area for snow storage & snowmelt
treatmentSource: Massachusetts Smart Growth Toolkit
Vegetated Filter StripsPretreatment and AttenuationVegetated Filter StripsPretreatment and Attenuation
• Mild vegetated slopes
• Adjacent to small parking lots and roadways
• Another opportunity for snow storage
• Mild vegetated slopes
• Adjacent to small parking lots and roadways
• Another opportunity for snow storage
Source: City of Portland, OR Source: City of Portland, OR
Source: Massachusetts Smart Growth Toolkit
Narrow roads; “Country drainage.”
• Shared driveways;• Houses sited with natural terrain;• Vegetation retained.
Short driveways and shallow front yard setbacks allow for rear yard retained vegetation.
Downspouts discharge to natural terrain for recharge.
www.bae.ncsu.edu/stormwater
Green Design
www.bae.ncsu.edu/stormwater
Green Design-Biofilter/bioretention-Green Roof-Rainwater Collection-Porous Paving: Gravel Pave-Waterless Urinals-Low-flow fixtures-Superinsulation (R21 walls & R30 roof)-High Performance Glazing on Windows-On Demand Water Heating-Daylighting-Duct System made of fabric-Over 75% of construction/demolition waste was salvaged or recycled-Recycled material used in walls, floors, and windows-Local material use
www.bae.ncsu.edu/stormwater
BioretentionBioretentionPermeable Pavement
CisternCistern
GreenroofGreenroof
LID (Commercial)
DisconnectedDisconnected
www.bae.ncsu.edu/stormwater
LID SiteLID Site
Create a Hydrologically Functional Lot
Residential
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www.bae.ncsu.edu/stormwater
Conservation
Open Drainage
Rain Gardens
Amended Soils
Rain Barrel
Residential
LID SiteLID Site Permeable Pavement
Create a Hydrologically Functional Lot
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www.bae.ncsu.edu/stormwater Aerial Photo Courtesy of Y. Lyda
LID (Institutional
)
www.bae.ncsu.edu/stormwater
level spreader
rain gardens
cistern/rain barrel
vegetated buffer
permeable pavement bioretention
Aerial Photo Courtesy of Y. Lyda
LID (Institutional
)
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Williamston High SchoolWilliamston High School
Green Design ExerciseGreen Design Exercise
Primary Conservation Areas(1) Wetlands
(2) Waterbodies
(3) Floodplains
(4) Steep Slopes
Secondary Conservation Areas
(1)Mature Woodlands (4) Wildlife Habitats
(2) Buffers around wetlands & waterbodies
(3) Prime Farmland (5) Historic/cultural areas
Green Design Case StudyGreen Design Case Study
Griffin Acres
The process begins with determining how many lots could be developed under conventional zoning; this is the base yield of the property. From that point, the plan development process follows four basic steps:
Source: Massachusetts Smart Growth Toolkit
Identify Conservation Value Areas on the site such as wetlands, significant trees or tracts of forest, habitat, cultural resources or buffer zones. Remove these from the “developable area”.
1.
Source: Massachusetts Smart Growth Toolkit
Place houses in the remaining area in a way that would maximize residents enjoyment of these areas by providing access to open space and preserving views.
2.
Source: Massachusetts Smart Growth Toolkit
Align roads and trails on the site to provide pedestrian and vehicle access.
3.
Source: Massachusetts Smart Growth Toolkit
4. Draw lot lines around the homes.
Source: Massachusetts Smart Growth Toolkit
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1. Meet with local officials to review current development ordinances (often, officials look favorably upon pre-development meetings).
2. Identify ways to work together to minimize development impacts.
3. Focus on LID (developer should have a general knowledge of practices he/she plans to implement).
4. Plan to make site visits with local officials/staff.
5. Since site design information comes from different sources, data should be synthesized into a single map.
Create a Green Design & Development Committee to review plans• Planners• Engineers• Architects• Landscape Architects• Biologists, Ecologists, and Hydrogeologists• Others• Also create incentive-based programs
Puget Sound Water Quality Action Team
-http://www.wa.gov/puget_sound The Low Impact Development Center
-http://www.lowimpactdevelopment.org Stormwater Research Center
-http://www.stormwatercenter.net U.S. Environmental Protection Agency
-http://www.epa.gov/owow/nps/urban.html UW Center for Urban Water Resources
-http://depts.washington.edu/cuwrm/
http://www.bae.ncsu.edu/topic/lid/