urban water quality issues - green design & development

http://www.bae.ncsu.edu/topic/lid/

Dwane Jones

[email protected]

919.249.5959

Introduction:

What is “Green Design & Development?”

Green Design & Development


Working Definition

Green Building and Development is environmental responsiveness. It is integrating water quality, and air

quality concepts with building technology.


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

+

Source: USGBC

Green Planning



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


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)


•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)


-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)


Integrating Green Design with Low Impact Development &

Conservation Design


•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


• 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


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


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


• Increased insulation

•Decreased heat island effect

•Decreased stormwater volumes and rates

•Decreased long-term replacement costs

•Increased property value

•Downsizing HVAC


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.


Green Design


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


BioretentionBioretentionPermeable Pavement

CisternCistern

GreenroofGreenroof

LID (Commercial)

DisconnectedDisconnected


LID SiteLID Site

Create a Hydrologically Functional Lot

Residential

+


Conservation

Open Drainage

Rain Gardens

Amended Soils

Rain Barrel

Residential

LID SiteLID Site Permeable Pavement

Create a Hydrologically Functional Lot

+

www.bae.ncsu.edu/stormwater Aerial Photo Courtesy of Y. Lyda

LID (Institutional

)


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

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:


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.


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.


Align roads and trails on the site to provide pedestrian and vehicle access.

3.


4. Draw lot lines around the homes.


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/



Dwane Jones

[email protected]

919.249.5959

urban water quality issues - green design & development

Technology

usgbc source

stormwater flow

andconvey stormwater

definition green building

maintaineach development

effects of water

manmade stormwater facility

surface runoff