About the Author

Teresa Burrelsman, is the founder of Eco Via Consulting, a sustainable building and organizational program consulting firm in Seattle, WA.

Teresa has been active in the sustainability and LEED industry for over 10 years. She has been a LEED Reviewer for the USGBC and led the LEED version3/2009 Visioning Process and developed early drafts of LEED Retail. She has worked on dozens of LEED projects, including retail, office and mixed-use.

Eco Via Consulting works with our clients to create their unique path to sustainability. We provide services in the following areas:

Sustainable & LEED Buildings

Programs, Research & Training

Public Outreach & Facilitation

www.ecoviaconsulting.com

©GreenCE, Inc. 2011

Please note: you will need to complete the conclusion quiz online at GreenCE.com to receive credit

Low-Impact DevelopmentA Sustainable Site Design Approach for LEED NC and O+M

T E R E S A B U R R E L S M A N

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T E R E S A @ E C O V I A C O N S U LT I N G . C O M

W W W. E C O V I A C O N S U LT I N G . C O M

W W W. S U S TA I N A B L E C O L L A B O R AT I O N N E T W O R K . C O M

gev00fCredit for this course is

1 AIA/CES LU Hour1 GBCI CE Hour

1 LEED Specific BD+C GBCI CE Hour1 LEED Specific O+M GBCI CE Hour

An American Institute of Architects (AIA) Continuing Education Program

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This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA or GreenCE, Inc. of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.

An American Institute of Architects (AIA) Continuing Education Program

Course Format: This is a structured, web-based course with a final exam.

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USGBC CE Program

Low-Impact Development:

A Sustainable Site Design Approach for LEED NC and O+M

USGBC Course ID: 90005338

Approved for 1 GBCI CE Hour for LEED Professionals and

1 LEED Specific BD+C GBCI CE Hour for LEED Professionals

1 LEED Specific O+M GBCI CE Hour for LEED Professionals

GreenCE, Inc.

Learning Objectives

By completing this course the LEED Professional will be able to:

Define Low Impact Development as a sustainable site

Describe which LEED credits can be achieved through a LID site approach

Discuss a LEED project example and how LID strategies were used

Incorporate LID processes and strategies into your LEED projects

Communicate the benefits of LEED Sustainable Sites strategies

SITE DEVELOPMENT CONTEXT

Section 1

Development Pressure on Ecosystems

Across the U.S. almost all water bodies are polluted to some degree due to stormwater run-off

Stormwater from our driveways, roads, parking lots and lawns contain heavy metals, toxins, and sediments

Site Design Impacts

With increased development comes a set of site impacts:

Wildlife habitat & ecosystem destruction

Economic impact of transit

Walkability and health impacts

Community connections

Linkages to tourism and recruitment

Increasing air pollution and climate change

Stormwater Runoff Problems

First, stormwater transports a mixture of pollutants such as petroleum products, heavy metals, animal waste and sediments from construction sites, roads, highways, parking lots, lawns and other developed lands, with the following results: Pollution has harmed virtually all urban creeks, streams and rivers in

Washington State. Stormwater is the leading contributor to water quality pollution of urban waterways

in the state. Two species of salmon and bull tout are threatened with extinction under the federal

Endangered Species Act. Loss of habitat due to stormwater and development is one of the causes.

Shellfish harvest at many beaches is restricted or prohibited due to pollution. Stormwater runoff is often one of the causes.

Stormwater likely contributes to the killing of high percentages of healthy coho salmon in Seattle creeks within hours of the fish entering the creeks, before the fish are able to spawn.

English sole are more likely to develop cancerous lesions on their livers in more urban areas. Stormwater likely plays a role.

Stormwater Runoff Problems

Second, during the wet, winter months, high stormwater flows can:

Cause flooding.

Damage property.

Harm and render unusable fish and wildlife habitat by eroding stream banks, widening stream channels, depositing excessive sediment and altering natural streams and wetlands.

In addition, more impervious surface area means less water soaks into the ground. As a result, drinking water supplies are not replenished and streams and wetlands are not recharged. This can lead to water shortages for people and inadequate stream flows and wetland water levels for fish and other wildlife.

Pollutants in Urban Storm Water

Table courtesy of UC Davis Extension, Department of Water & Land Use

Pre-Development Hydrology

Pre-Development Environment

Storm events are moderated by infiltration, evaporation and transpiration

Ground water is recharged to sustain summer stream flow

Post-Development Hydrology

Post-Development Environment

Surface run-off increases

Less water infiltrated for groundwater recharge

Increased sediments and pollutants delivered to water bodies

Increased flow can cause flooding and wash away aquatic habitat

WHAT IS LOW IMPACT DEVELOPMENT?

Section 2

Low Impact Development

Low Impact Development is an approach to site design that uses natural systems rather than conventional infrastructure to mitigate stormwater.

LID Objectives

Mimic site’s predevelopment hydrologic function to reduce development impact on receiving water bodies by: Filtering pollutants with soil, plant and paving materials

Minimize, detain, and retain post development runoff on-site

Low Impact Development seeks to recreate natural hydrology by 3 key measures:1. Treat rain drop near where it fell2. Several smaller BMPs create redundancy3. Return to distributed vs. regional

treatment

Development Impact on Urban Streams

Goal: Look at growth, habitat, water, & energy and

balance development and natural needs

LID Strategies

Conservation measures

Retain forest and planted areas & restore habitat .

Protect native soils that drain well, and restore the draining capacity of construction compacted soils.

Protect topographic site features that slow, store and infiltrate stormwater.

Protect natural drainage patterns and features.

Site planning

Use a multi-disciplinary approach with planners, engineers, architects, and landscape architects.

Place buildings and roads away from critical areas and well-draining soils.

Minimize impervious surfaces and completely disconnect them.

Distributed management practices

Manage stormwater as close to its origin as possible with multiple, small scale LID techniques.

Design site that slows surface flows.

Increase the reliability by using multiple, redundant stormwater controls.

Use the stormwater controls as site amenities.

Reduce the reliance on traditional collection and conveyance stormwater practices.

Maintenance and education

Develop reliable, long-term maintenance programs with clear and enforceable guidelines.

Educate owner/operators and staff on proper operation and maintenance practices.

LID Techniques

LID can effectively be described as a means of “Distributed Stormwater Management”, which uses the following individual techniques, typically in combination to create redundancies.

Bio-Retention Bio-Swales Plants Tree Box Filters Soil Amendments Pervious Pavement Rainwater Harvesting Subsurface Retention Green Roofs Pin Foundations

What Does LID Look Like?

Left: Green roofs that absorb and filter rain water (Seattle City Hall)

Right: Streets that drain to vegetated swales and create walkable neighborhoods

Left: Permeablepavement with under-vault that treats run-off and slowly releases it to the watershed

Right: Rain gardens that use stormwater instead of irrigation

The 3 R’s of Sustainable Stormwater

Reduce impervious area

Retain water on-site via infiltration & evaporation

Re-Use water on site by harvesting rainwater for irrigation or other non-potable uses

Image credit: LIDC

This bioswale in Seattle captures stormwater in a vegetated depression with engineered soils. Water-loving plants, mulch and soil amendments create a system that absorbs and treats run-off. Retention techniques like this can often reduce or eliminate the need for conventional stormwater infrastructure.

HOW DOES LID APPLY TO LEED?

Section 3

LEED & LID

LID is an aspect of sustainable site design LID can also support water savings LID may involve local, reused or recycled

materials

Therefore, LID strategies can help achieve LEED

credits in: Sustainable Sites (SS) Water Efficiency (WE) Materials & Resources (MR) Innovation in Design (ID) Regional Priority (RP)

Street trees help reduce urban heat island effect, while also treating stormwater run-off and reducing impacts on local water bodies.

LEED & LID

LID strategies will tally differently across LEED systems. In this course, we will focus on new and existing building construction:

LEED 2009 New Construction (NC) Core & Shell (CS) Schools Existing Buildings: Operations & Maintenance (EBO&M) Commercial Interiors

LEED for Neighborhood Development (LEED ND) Credits will be similar in LEED Homes, LEED Healthcare & LEED for

Retail NC

LEED & SUSTAINABLE SITES

Matching the site to appropriate use

Enable alternative transportation (train, bus, carpool, bikes, & walking)

Native and adapted landscaping

Reduce need for chemical pesticides & fertilizers and irrigation

Protect surrounding habitats

Manage storm water

Reduce heat island effect

Eliminate light pollution

SUSTAINABLE SITE DESIGN

The LEED for New Construction Reference Guide describes sustainable site design as:

Overlap with LID

RELATED CREDITS AT A GLANCE

Sustainable Sites Credits (7) SSc5.1 Protect/Restore Habitat*

SSc5.2 Maximize Open Space*

SSc6.1 Stormwater – Quantity Control*

SSc6.2 Stormwater – Quality Control*

SSc7.1 Heat Island – Non-roof*

SSc7.2 Heat Island – Roof*

SSc9 Site Master Plan (LEED Schools)

Water Credits (10) WEc1 Water-Efficient Irrigation WEc2 Innovative Waste Water

Technologies* WEc3 Water Use Reduction*

Materials Credits (6) MRc3 Materials Reuse* MRc4 Recycled Content* MRc5 Regional Materials*

Innovation Credits Exemplary Performance in Credits

Above with *

LEED 2009: NC, CS, SCHOOLS, RETAIL

17 Key LID points in SS and WE + MR Contributes to up to 6 additional + ID Potential

RELATED CREDITS AT A GLANCE

Sustainable Sites Credits (up to 5 points)

SSc3 IPM, Erosion & Landscape Management Plan

SSc5 Protect/Restore Habitat*

SSc6 Stormwater – Quantity Control*

SSc7.1 Heat Island – Non-roof*

SSc7.2 Heat Island – Roof*

Water Credits (up to 10 points)

WEc2 Indoor Water Use Reduction*

WEc3 Water-Efficient Landscaping

Innovation Credits Exemplary Performance in Credits

Above with *

LEED O&M

15 Key LID points + ID Potential

LID & LEED Credit Details

The major LID-related LEED credits relate to the following strategies:

1. Increased open space amenities - NC SSc5.2, O+M SSc5

2. Stormwater Quantity Reduction - NC SSc6.1, O+M SSc6

3. Stormwater Quality – NC SSc6.2

4. Native and adapted plants - NC SSc5.1, NC WEc1

5. Shading and green hardscapes – NC & O+M SSc7.1

6. Green roofs – NC & O+M SSc7.2

7. Water reuse – NC WEc1, NC/O+M WEc2, WEc3

8. Green materials – NC MRc3, MRc4 & MRc5

Open Space

Infiltrate and store run-off through engineered, graded and planted depression.

Underdrain or retention vault optional.

Includes:

• Rain gardens

• Bio-retention cell

• Vegetated Swale

• Tree Box Filters

• Stormwater Planters

Stormwater Quantity & Quality

By installing bio-retention areas such as “rain gardens” and bio-swales, the landscape can do double duty – be beautiful AND treat and infiltrate run-off.

Components include:

• Amended soil

• Drainage area sized for site

• Water-loving plants

• Underdrain, in some cases

The Highpoint neighborhood in Seattle used rain gardens and bio-swales as part of a LID approach that reduced stormwater run-off by 65%.

Native & Adapted Plants

• Preserve existing open space

• Create new open areas

• Water loving plants in retention areas

• Low-water landscapes in non-retention areas

• Preserve existing trees

Shading & Green Hardscapes

• Street trees reduce drainage infrastructure

• Established trees absorb up to 3x more water

• Larger trees also provide more shade

• Light colored pavements reflect heat

• Pervious pavements treat stormwater and can combine with vaults for storage and reuse

Street Trees & Curb Bulbs, Portland, OR. Credit: LIDC

Permeable andlight colored pavements infiltrate stormwater. The gravel catches bacteria and pollutants.

Shoreline, WA

Credit:T. Burrelsman

Green Roofs

Planted roof that adds infiltration, evapotranspiration and filtering capacity to reduce stormwater runoff. Also reduces urban heat build-up.

Components:

• Root barrier

• Engineered soil mix

• Low water plants

• Irrigation system (opt)

City Hall, Seattle, WA

Images: American Hydrotech

Ballard Library, Seattle, WA

Water Reuse

Capture rain water for use.

Applicable for:

• Commercial reuse in toilet flushing

• Landscape irrigation

• Residential gardening

Green Materials

Don’t forget landscaping when it comes to green materials:

• Local mulches and plants

• Reuse cuttings from site clearing as mulch and amendments

• Site furniture can be local or contain recycled content

• Paving can be specified with recycled aggregates and fly ash

Putting it All Together

Let’s look at a LEED project and how it used a combination of low impact development strategies to create a beautiful civic space with good green performance:

Uses less water

Treats neighborhood stormwater

Benefits the local watershed

Creates desirable open space

Northgate Civic Center

Site: 3.5 acres

Square Feet: 10,000 library, 20,000 community center

Construction Cost: $295/sq. ft. library;

$228/sq. ft. community center

Completed: July 2006

LEED NC v2.1 Gold

Architect: Miller|Hull

Owner: City of Seattle & Seattle Library

Images: Miller|Hull

Northgate Civic Center

• 267,000 gallon detention vault below the lawn

• Sized for 100 YR, 23 hr storm

• Multiple agency combined budgets –Transportation, Library, Parks

• Site handles its own run-off plus 1 acre adjacent natural area and 5th Ave NE

Stormwater Details:

October through April, water steadily released to storm system at rates set by new city standards, which match those of the same land without any impervious surfaces.

From May to September, the releasing pump is reset for use only on site, and the water is collected and drawn down for irrigation.

Through water harvesting, the system yields approx 300,000 gallons per year diverted

Combined with a reduction of impervious surfaces, stormwater runoff leaving the site was reduced by over 30 percent after redevelopment.

Northgate Civic Center

The new Northgate Civic Center provides a community center and a library – and creates a much needed focal point to the neighborhood.

Utilizing a sustainable site and LID approach contributed to LEED credits in the Sustainable Sites and Water Efficiency Categories.

Northgate Civic Center

In addition to LID features, the project is located along future light rail and future mixed-use housing.

The project is an excellent example of using urban infill to build community and contribute to a sustainable city.

LID LEED credits at Northgate

Sustainable Sites: SS credit 6.1: Stormwater Quantity Reduction by using rain

gardens and bio-swales for infiltration and a vault below the lawn for storage for irrigation and slow release of excess water to Thornton Creek.

SS credit 6.2: Stormwater Quality Treatment by landscape features including rain gardens, bioswales and even the vault.

SS credit 5.1: Increased Open Space. The project created a beautiful park that does double duty – providing a public amenity and treating stormwater!

Water Efficiency: WE credit 1.1 & 1.2: Rainwater harvesting supplies all

irrigation water. Drip irrigation and low-water plants allow landscape to thrive on available rain water.

Northgate Civic Center

LID LEED credits at Northgate

Innovation & Design Process:

The project achieved an ID credit for creating a Pesticide-Free Park. Proper plant selections suited to the local climate, mulching and soil amendments, and rain gardens and swales that capture site run-off create hearty landscapes that resist infestation.

Northgate Civic Center

LID & LEED Benefits:

46% reduction in energy use – $34,500 in annual savings

77% reduction in potable water use –$2,500 in annual savings

94% construction waste diverted from landfills through recycling

30% decrease in the rate of stormwater runoff

19.5% decrease in impervious surface area

Images: Miller|Hull

Northgate Civic Center

Lessons Learned:

Combined agency budgets critical to civic/community development

Process champions and support from Mayor enabled success

Large underground vault stores water for use in the dry season Substantially reduces irrigation

Run-off will closely resemble pre-settlement levels to Thornton Creek

Set sustainability goals early LEED Gold decision made late in design

Impacted costs

Increased constraints limit options

THE LID PROCESS

Section 4

Design for LID - Process

Design/Planning

Construction

Maintenance

PolicyFundingGuidelines

PermittingNew Methods

BudgetStaff

LID Team

Owner/Developer

Permit Liaison

Civil Engineer

Landscape Architect

Architect or Designer

Sustainability/LEED Consultant

Contractor

Permitting Agencies

Community

An integrated design team, where multiple disciplines come to the process early in design, will make achieving high performance, LEED and LID projects easier and more cost-effective.

Steps

As with any new LEED strategy, LID design should begin with a conversation – and doesn’t end until maintenance issues are addressed!

1. Discuss Site Design approach and goals with client2. Put lid strategies in right place (downslope from foundations &

up slope from stormwater infrastructure)3. Size features – estimates okay for early design but can’t beat

calculations for final design4. Evaluate existing soils5. Design soil amendments based on climate & soil6. Select native and low-water plantings for lower maintenance7. Install8. Maintain (include tips in O&M Manual)

Green, LID & LEED Communication

Effective communication is a key factor in developing successful projects and for sharing the ideas and concepts surrounding sustainable stormwater practices.

During implementation, frequent and open communication can eliminate obstacles before they appear and prevent misunderstandings.

If your goal is to encourage implementation of green or sustainable stormwater practices, it is important to be able to articulate the benefits of these practices to clients, the public, or to public or private developers.

Communicating Benefits

Example benefits to local governments: Protecting water quality helps protect real estate values & tax revenues.

Reduced inflow – less stormwater leaking into sanitary sewers means less volume of water reaching sewage treatment plant.

Reduced filtration costs – bioretention instead of piped stormwater and sand filters saved $250,000 along Anacostia River in Washington, DC.

Reduced public expenditures on stormwater infrastructure including expensive retrofits.

Reduced system-wide operations and maintenance costs of pipe infrastructure.

Extend useful life of central pipe infrastructure as populations in-crease.

Reduced regulatory costs associated with water-quality impacts, such as threats to sensitive species, NPDES compliance, etc.

Communicating Benefits

Example benefits to the community: Protecting natural ecosystems through sound LID practices provides benefits

to communities such as: reduced flooding, improved water quality, increased groundwater recharge, improved air quality, enhanced aesthetics, enhanced property values, increased open space, and carbon sequestration. These are all ecosystem services.

Protecting water quality through LID maintains the value of clean water, which is usually less expensive than cleaning contaminated water. Not having to clean contaminated water is an avoided cost.

Clean water is a quality of life benefit; although difficult to quantify, its value may rival or exceed more tangible benefits. For example, protecting human health is the driving force behind the nation’s water supply protection program.

Reduced flooding, reduced stream erosion, and reduced pollutant loading to downstream waters.

Communicating Benefits

Example benefits to developers:

Increased number of buildable lots – reducing the need for stormwater retention ponds may result in more lots available for homesites.

Less spent on infrastructure – replacing curb, gutter, and storm sewers with roadside swales saved one developer $70,000 per mile, or $800 per residence.

Increased property values – lots in LID neighborhoods sold for $3,000 more than lots in competing areas not using LID.

Initial savings from LID are usually accomplished through less conventional stormwater infrastructure, less paving, and lower site preparation costs.

Construction Administration

Implementing erosion & sedimentation practices is critical for LID and is a LEED prerequisite. Remember to protect drain inlets and outlets

Protect catch basins

Cover permeable paving immediately after pouring, as voids enhanced drying. No trowels or floats, no dowels.

Installers should have proper certifications and/or experience (Permeable Pavement Certification, etc.)

Maintenance Items

Monitor sedimentation at drains

Permeable paving requires vacuum or pressure washer

Landscaped retention areas require maintenance, similar to any landscape

Inform staff of proactive measures, maintenance and repair needs of LID techniques

Establish a maintenance schedule

Sample Schedule

SUMMARY

Section 5

LID & LEED Go Together!

Using low impact development techniques contributes to a number of LEED credits, particularly in the Sustainable Sites & Water Efficiency categories.

Low impact development contributes to site designs that create open space, habitat, and walkable communities.

Low impact development is a cost effective approach that facilitates development without negatively impacting local watersheds.

LID Data & Case Study Resources

For additional project examples and data:

US EPA LID Resources www.epa.gov/nps/lid/

US EPA Study: Reducing Stormwater Costs through Low Impact Development (LID) Strategies and Practices www.epa.gov/nps/lid

Sightline Report 2010: Cleaning up WA Toxic Runoff http://www.sightline.org/research/pollution/res_pubs/curbing-

stormwater-pollution

Course Summary

Now the design professional will be able to:

Define Low Impact Development as a sustainable site

Describe which LEED credits can be achieved through a LID site approach

Discuss a LEED project example and how LID strategies were used

Incorporate LID processes and strategies into your LEED projects

Communicate the benefits of LEED Sustainable Sites strategies

AIA Course Evaluation

In order to maintain high-quality learning experiences, please access the evaluation for this course by logging into CES Discovery and clicking on the Course Evaluation link on the left side of the page.

Low-Impact DevelopmentA Sustainable Site Design Approach for LEED NC and O+M

T E R E S A B U R R E L S M A N

E C O V I A C O N S U LT I N G

( 2 0 6 ) 6 1 8 - 1 8 4 5

T E R E S A @ E C O V I A C O N S U LT I N G . C O M

W W W. E C O V I A C O N S U LT I N G . C O M

W W W. S U S TA I N A B L E C O L L A B O R AT I O N N E T W O R K . C O M

gev00fCredit for this course is

1 AIA/CES LU Hour1 GBCI CE Hour

1 LEED Specific BD+C GBCI CE Hour1 LEED Specific O+M GBCI CE Hour

©GreenCE, Inc. 2011

Please note: you will need to complete the conclusion quiz online at GreenCE.com to receive credit