ECOLOGICAL SITE DEVELOPMENT Regional Strategies forDesign, Construction and Maintenance

© Greater Vancouver Regional District 2007

Copyright to this publication is owned by the Greater Vancouver Regional District (“Metro Vancouver”). Permission is granted to produce or reproduce this publication, or any substantial part of it, for personal, non-commercial, educational and informational purposes only, provided that the publication is not modifi ed or altered and provided that this copyright notice and disclaimer is included in any such production or reproduction. Otherwise, no part of this publication may be reproduced except in accordance with the provisions of the Copyright Act, as amended or replaced from time to time.

While the information in this publication is believed to be accurate, this publication and all of the information contained in it are provided “as is” without warranty of any kind, whether express or implied. All implied warranties, including, without limitation, implied warranties of merchantability and fi tness for a particular purpose, are expressly disclaimed by Metro Vancouver and Sharp & Diamond Landscape Architecture Inc.

The material provided in this publication is intended for educational and informational purposes only. This publication is not intended to endorse or recommend any particular product, material or service provider nor is it intended as a substitute for engineering, legal or other professional advice. Such advice should be sought from qualifi ed professionals.

COPYRIGHT AND DISCLAIMER

Cover Photo Credits: Randy Sharp, District of Sechelt, Interlocking Concrete Paving Institute

TABLE of CONTENTS 1

TABLE OF CONTENTS

Introduction ...................................................3

1. Strategies for Ecological Site Development.........................................9

1.1 Planning and Design.................................................9 1.1.1 Integrated Design Process 1.1.2 Documenting the Natural and Human Factors Influencing the Site 1.1.3 Optimizing Energy Performance through Building Form and Climate- Specific Design 1.1.4 Site Organization, Circulation, Servicing and Open Space 1.2 Site Management During Construction.....................14 1.2.1 Involvement of Contractors and Suppliers 1.2.2 Construction Waste Management 1.2.3 Soil Management 1.2.4 Erosion and Sedimentation Control 1.2.5 Hydroseeding, Revegetation and Protection of Soils

1.3 Rainwater Management and Biofiltration.................17 1.3.1 Rainwater Harvesting 1.3.2 Porous Pavement 1.3.3 Vegetated Swales and Biofiltration 1.3.4 Rain Gardens 1.3.5 Absorbent Landscapes 1.3.6 Underground Storage Systems 1.3.7 Constructed Wetlands and Ponds

1.4 Water Efficiency......................................................23 1.4.1 Plant Selection and Waterwise Landscaping 1.4.2 Landscape Irrigation

1.5 Urban Heat Island Reduction..................................25 1.5.1 Street Trees and Shade on the Site 1.5.2 High Albedo Paving Materials 1.5.3 Green Facades and Living Walls 1.5.4 Green Roofs 1.5.5 White Roofs 1.5.6 Combining Rooftop Technologies

1.6 Materials, Resources and Maintenance..................31 1.6.1 Reuse of Materials 1.6.2 Recycled Materials for Construction 1.6.3 Regional Materials 1.6.4 Local Manufacturers 1.6.5 Organic Landscape Maintenance 1.6.6 Composting and Soil Management

2. Innovations in Design........................................35

2.1 Visible Infrastructure...............................................35

2.2 Urban Amenities.....................................................37

2.3 Urban Agriculture.....................................................38

2.4 Wastewater Technologies.........................................39 2.4.1 Living Machines 2.4.2 Grey Water Treatment

2.5 Bicycle Facilities......................................................41 2.5.1 Bicycle Storage

2.6 Lighting..................................................................42 2.6.1 Lighting Strategies

2.7 Acoustics.................................................................43

2.8 EcoDensity.............................................................44

3. Sustainable Technology Series.......................47

Case Study #1: Extensive Green Roof .................47

Case Study #2: Pervious Concrete..........................55

CREDITS:

writing, research & photography* Randy Sharp

editing:Shaun Smakal

formatting and graphic support:Bryce Gauthier, Ken Larsson and Jennifer Zatser

*unless otherwise credited

UniverCity at Simon Fraser University (SFU) is a pedestrian oriented, new community on Burnaby Mountain.

Photo by Stefan Lorimer

INTRODUCTION 3

INTRODUCTION

Ecological Site Development is written to inform designers, policy makers and the development industry about site planning, design, construction and maintenance from an ecological perspective. This guidebook focuses on development and visible infrastructure strategies that:• protect / restore natural features on a site• reduce the loadings to municipal infrastructure and the watershed• provide solutions that are eco-effective • encourage local businesses to develop sustainable products for the marketplace• build healthy cities that enhance the quality of life• foster integration of landscape and architecture.

It is the intent of this document to assist those involved with development and construction in Metro Vancouver—developers, architects, engineers, scientists, policy makers, landscape architects, contractors and suppliers of sustainable products. This guidebook offers the knowledge necessary to help make more informed choices about the methods and strategies used to conduct business and to develop sites within Metro Vancouver.

Ecological Site Development covers a wide range of site engineering, green architecture and landscape strategies and will be updated as new technology, knowledge and practices are developed or made available in British Columbia. The reader will also be directed to other independent technical resources and links to relevant websites. This document may be used as a companion to the Leadership in Energy and Environmental Design (LEED®) Reference Package and will highlight where LEED® credits can be earned. In addition, innovative biological and engineered solutions are presented that go beyond currently available LEED® credits.

Objectives

The goal of ecological site development is to create biologically diverse, vibrant and livable communities that enhance our social well-being and our local economy. However, before these benefits can be fully realized, we need to rethink the way we design and build on the land.

The first objective is to transform the marketplace. North America, in general, is lagging behind much of Europe and Japan in the implementation of environmental construction techniques; and British Columbia is no exception. Vancouver and Metro Vancouver provide an ideal context for implementing ecological practices and sustainable products within the region and helping to distribute them across North America. The second objective focuses on the creation of new business opportunities within B.C. and Metro Vancouver.

“The LEED® Green Building Rating System is a voluntary, consensus-based, market driven green building rating system based upon existing proven technology. It evaluates performance on a range of ecological and human health protection issues from a whole building perspective over a building’s life cycle, providing a definitive standard for what constitutes a ‘green building’.” Canada Green Building Council.

www.cagbc.org

Permeable landscape in a checkerboard design at the Pintura, by Intracorp Developments, Vancouver.

Lightweight rubber track equipment minimizes damage to the environment.

BC Gas (Terrasen) Building, an ecological site development in Surrey.

4 INTRODUCTION

The third objective is to address the red tape, engineering standards and regulatory barriers to developing cost effective and ecological sites. Policies and guidelines need to respond to and encourage more beneficial forms of design, development and construction.

Organization

Ecological Site Development is organized into three main parts:

• Part 1, Strategies for Ecological Site Development, covers proven strategies to enhance the ecological performance of sites in our region. These strategies may be applicable to achieving LEED® credits.

• Part 2, Innovations in Design explores several emerging strategies that may go beyond LEED® certified projects. Such strategies include social sustainability, urban agriculture and innovative wastewater treatment, or technologies new to Metro Vancouver.

• Part 3, Sustainable Technology Series, includes detailed case studies of an extensive green roof design and installation and of an application of pervious concrete. In the future, the Sustainable Technology Series will be expanded with more case studies.

An example of low impact development (LID ) at Eagle Mountain Park, City of Coquitlam. Four parking lots demonstrate four paving strategies including reinforced grass, interlocking permeable pavers, asphalt and a hybrid of asphalt and pavers. Flow rate meters are connected to each of the four catch basins for stormwater monitoring.

Mechanized installation of unit pavers, the SF Group

See the book Biomimicry: Innovation Inspired by Nature, by Janine M. Benyus.

INTRODUCTION 5

Ecological Site Development

This guidebook is titled Ecological Site Development not because the strategies outlined are solely applicable to landscape architects, designers and contractors, but because their efforts result in an entire city, a development, a single building, a street or even just a garden wall that is situated within, and connected to, the larger landscape. We are responsible for planning, developing and constructing an infrastructure for living that extends into a global society where the demand for resources is quickly surpassing the supply.

So what is ecological site development? It is development that results in a landscape that is made up of a visible and ecologically functional framework of infrastructure. Both the site and surrounding landscape are pervious, living breathing environments that absorb stormwater, pollutants and waste as well as provide for cooler, quieter and more comfortable buildings. The building and landscape function together in harmony to replicate or restore natural systems and habitat. Green building surfaces moderate the microclimate and insulate the structure through shade, evaporative transpiration, thermal mass and natural ventilation.

Permeable landscapes, site surfaces and building components are based on a ‘kit of parts’ containing durable, long-lasting materials that allow for a maximum of flexibility. Modular site components are reusable and adaptable to changes in the site’s use and building program.

By mimicking ecological processes on site and making them an important and visible factor of design and construction, designers and contractors have the opportunity to create a new, functional landscape. The new landscape is both aesthetically pleasing and part of an eco-effective process where waste is no longer a destructive and unhealthy result, but a productive and healthy component of a self-sustaining human infrastructure.

Several B.C.-based developers, organizations and municipalities are already passionate about ecological site development. One of these is VanCity Credit Union. “We are committed to supporting alternative transportation, environmental education, green business, a green building grant program and emerging green sectors,” says Jacques Khouri, President & CEO, Vancity Enterprises Ltd. (VCE). Operating with a mandate for socially responsible real estate development, VCE is co-developer of the Dockside Green project in Victoria, B.C., with Windmill Developments and the City of Victoria. The development is a triple bottom line development, meaning that it emphasizes a design that integrates environmental, economic and social sustainability. (see www.docksidegreen.com )

A Permeable Paving System (See the Interlocking Concrete Paving Institue website at www.icpi.org).

The GVRD Publication, Green Construction: Introducing Green Buildings and LEED® to Contractors.

6 INTRODUCTION

Criteria for Selecting Strategies

Many of the site development and landscape strategies in this guidebook were selected based on the following general criteria:

• Utilize eco-effective technologies already in practice or strategies relevant to the geography and microclimate of the region.

• Replicate the function of natural systems.

• Provide stormwater management, innovative wastewater treatment and infiltration to protect streams and aquatic areas.

• Initiate a cradle-to-cradle approach (waste to food) which reuses, up-cycles (re-fabricates) and biodegrades materials in the landscape.

• Purchase local products and use on-site materials to reduce CO2 emissions from transportation, and to decrease noise and dust from trucks.

• Engage local businesses and local expertise to support the regional economy.

• Allow project partners and contractors to collaborate and develop new approaches and innovative technologies;

• Provide effective construction management and establish maintenance programs to provide long-term system performance and to ensure the vitality of plant materials.

USEFUL RESOURSES:

Green Buildings BC Resources Guide (see www.greenbuildingsbc.com/new_buildings/resources_guide)

Green Construction, Introducing Green Buildings & LEED® to Contractors, 2004, BuildSmart, GVRD

Sustainable Building Design: Principles,Practices and Systems, 2003, BuildSmart, GVRD (see www.metrovancouver.org/buildsmart/PDFS/sustainablebuilddesprinciplespracticessys4.pdf) GVRD Regional Case Studies, the Sustainable Region Initiative (see www.metrovancouver.org/sustainability/casestudies.htm)

Green architecture and living walls of Expo 2005 in Aichi, Japan (see www.greenrooftops.com)

INTRODUCTION 7

The Current State Of EcologicalDevelopment in Metro Vancouver

Metro Vancouver is fortunate to have a favorable climate, an abundance of natural resources and a sophisticated development industry. We export our professional expertise and building skills around the world. As well, the major post secondary institutions including the University of British Columbia (UBC), British Columbia Institute of Technolobgy (BCIT), Emily Carr Institute of Art and Design, Simon Fraser University (SFU) and Kwantlen University College have multi-disciplinary design studios and are collaborating with the building and landscaping industries.

There are several developers and many architects with a strong commitment to innovative and ecological design. Landscape architects, nursery suppliers and landscape contractors have updated the B.C. Landscape Standard, a source of detailed landscape construction practices and a reference for technical specifications (see www.bclna.com and www.bcsla.org). In addition, Metro Vancouver compiles the BuildSmart Green Building Product Directory (see www.metrovancouver.org/buildsmart).

The successful marketing and promotion of sustainable products, local building materials and design practices is generating outstanding economic opportunities within the region. Examples include:

• native plant nurseries in the Fraser Valley and on the islands• growing media from forest by-products, green waste and compost• timber certified by the Forest Stewardship Council• aggregates for infiltration gravels and structural soils• permeable pavers and site furnishings that are manufactured locally• the Water Balance Model and stormwater management expertise• green architecture and microclimate landscape design• green roof products and technical expertise.

Ecological Site Development is a ‘living document’ designed to keep those in the development industry up-to-date on ecological site development, design and construction. It focuses on the visible and ecological strategies through which sustainable development and construction can be achieved. This guidebook follows a modular format that is designed to be updated and expanded on a regular basis as new technology, knowledge and construction practices become available to the development industry.

We recognize that innovation in the development industry is often the outcome of an integrated design process whereby project partners, designers, suppliers and contractors meet to brainstorm and develop new approaches to site development techniques. Many of these strategies are being implemented in the Lower Mainland on a microscale.

BCIT Green Roof Research Facility, BCIT. The BCIT Green Roof Research Facility, displays sustainable products and monitors them for stormwater and thermal performance. (see www.greenroof.bcit.ca).

8 INTRODUCTION

Metro Vancouver and the author welcome your input into design innovation and practical solutions. Please forward your suggestions, accounts of your experiences, photos and project examples to:

Business Advisor, Policy and Planning,Metro Vancouver,4330 Kingsway, Burnaby BC V5H 4G8T:604.432.6200e-mail: buildsmart@metrovancouver.org

author:

Randy Sharp, BCSLA, CSLA, ASLA, LEED® Accredited ProfessionalSharp & Diamond Landscape Architecture 602-1401 West BroadwayVancouver, BC V6H 1H6T: 604.681.3303e-mail: randy@sharpdiamond.comwww.sharpdiamond.com

Despite the advantages already present within Metro Vancouver, there are a number of barriers restricting green building and ecological site development. For example, within the City of Vancouver Engineering Department, the Sewers Branch is advocating the use of permeable materials and alternative paving systems. However, the Streets Branch allows only cast in place (CIP) broom fi nish concrete or exposed aggregate concrete for new city sidewalks, and asphalt for roadways. This policy for municipal streets effectively seals all surfaces often sending stormwater into the combined city sewers that overfl ow with raw sewage into English Bay and the Fraser River during heavy rain events.

UniverCity at SFU. The new community is the result of an integrated design process.

Photo by Stefan Lorimer

“The fragmentation of the building process into so many different disciplines has led to a gross simplification of the issues involved in building.” Gary L. Strang, “Infrastructure as Landscape,” Landscape Architecture, pg. 14, vol. 10, no. 3, 1996.

Integrated design process meeting, GVRD

STRATEGIES 9

1. STRATEGIES FOR ECOLOGICAL SITE DEVELOPMENT

1.1 Planning and Design

Ecological development requires a knowledgeable design team that has a detailed understanding of natural systems, energy modelling and long-term building performance as well as the municipal approval process. A thorough technical grounding in building systems, the local microclimate, on-site project experience and cost-effective, practical solutions is also essential for all team members.

The ecological site development strategies presented in this section are eco-effective, meaning they provide increased ecological benefits over traditional development methods and remain cost-effective. The strategies relate to the design process, energy consumption, site servicing, construction efficiencies, water supply and reduction of waste in the industry.

1.1.1 Integrated Design Process

The integrated design process (IDP) is a multidisciplinary, collaborative process involving all of the design and construction disciplines in a project from the very beginning. The IDP team, made up of design engineers, architects, contractors, landscape architects, specialized consultants and the client can explore design alternatives that result in innovative ecological site development.

1.1.2 Documenting the Natural and Human Factors Influencing the Site

A site’s environmental, cultural and economic characteristics, as well as opportunities and constraints for development need to be surveyed and documented at the start of a project.

Natural processes generally dominate on greenfield sites, while existing infrastructure and land use greatly influence brownfields or urban infill projects. Topography, slopes, soil conditions, water resources, vegetation, urban form and land economics may determine the most effective approach to locating buildings and open space. Urban design policies and guidelines in various neighbourhoods may address social concerns, character, and the ‘fit’ of a development into the local surroundings and the greater community.

Redevelopment of a brownfield site at South East False Creek, Vancouver.

Stormwater retention pond and wildlife habitat enhancement at UniverCity, SFU.

Existing forest at Burnaby Mountain, SFU.

10 STRATEGIES

Some of these parameters may include roadway and streetscape design, maintaining a human scale for the built form, outdoor amenities, public art, pedestrian facilities, lighting and crime prevention through environmental design. In addition to the immediate physical adjacencies to the site, the relationship of the site to larger patterns of land use, transportation, open space and infrastructure needs to be identified and documented.

MAPPING AND RESOURCES

Most Metro Vancouver municipalities have extensive GIS mapping and detailed air photos available. Natural Resources Canada provides its Geological Map of the Vancouver Metropolitan Area (Geomap), which has multiple overlays showing fl ood hazards, slopes and landslides, groundwater and aquifers, at gsc.nrcan.gc.ca:80/urbgeo/geomapvan/geomap10_e.php. The Endangered Species and Ecosystems in British Columbia website at www.env.gov.bc.ca/wld/serisk.htm provides links to detailed information on rare and endangered species and ecosystems in B.C. and provides links to agencies working with endangered species. The B.C .Species and Ecosystems Explorer, at srmapps.gov.bc.ca/apps/eswp/, is a search tool for fi nding provincial red-listed and blue-listed species and ecological communities by biogeoclimatic unit. Direct links are provided to relevant publications about rare organisms and ecological communities as well as species distribution, life histories, conservation needs and recovery plans.

The interface between the Agricultural Land Reserve (ALR) and residential development, Delta.

STRATEGIES 11

Refer to LEED® SS 1, Site Selection: Some properties or portions of sites may not be suitable for development. Provincial and Federal regulations as well as municipal zoning discourages or prohibits buildings, roads or parking within the following areas: • the agricultural Land Reserve (mandatory policy in B.C.) • wetlands within 30.5m setback (mandatory policy in B.C.) • fl oodplains (mandatory policy in BC) • ecologically sensitive lands • lands that provide habitat for rare or endangered species.

Refer to the B.C. Fish Protection Act ( see www.env.gov.bc.ca/habitat/fi sh_protection_act/) and the Endangered Species and Ecosystems in British Columbia website at www.env.gov.bc.ca/wld/serisk.htm.

Metro Vancouver’s Seymour–Capilano Filtration Plant Landscape Site Restoration Plan with Legend : The Seymour–Capilano Filtration Plant site is consolidated in area to conserve a large parcel of forest as part of the Lower Seymour Conservation Reserve. Site planning respected the need to protect stands of ecologically signifi cant trees (Douglas-fi r and Sitka Spruce). The pre-construction habitat values of the Seymour ecosystems were mapped by a biologist to produce a Biodiversity / Ecosystem Ranking System. For restoration landscapes, a Potential Biodiversity for each Rehabilitation Zone was prepared and will be monitored post construction. Fencing to protect trees was installed prior to site clearing and was maintained for the duration of construction.

Broadway Tech Centre, a brownfield site in Vancouver. Building orientation, shape and mass are designed to reduce energy consumption.

12 STRATEGIES

1.1.3 Optimizing Energy Performance through Building Form and Climate-Specific Design

The shape and mass of a building, as well as its orientation to the sun, natural light and wind, are key components of reducing energy consumption and creating a pleasant indoor environment. Harvesting free energy is accomplished by sculpting the form of the building to maximize passive solar heating, natural ventilation and penetration of sunlight into interior spaces.

A design team consisting of the architect, landscape architect and a specialist in energy engineering can explore alternative massing concepts. Testing of building form and orientation early in the design process may include preparing 3D conceptual models, shadow diagrams and computer energy modelling. The addition of thermal massing or living walls on the south and west facades can reduce daily temperature variations. Strategically placed deciduous trees can provide wind protection and shade during the summer and let in sunlight during winter.

Refer to LEED® EA 1, Optimize Energy Performance.

“Arctic ice retreats dramatically,” The Vancouver Sun, September 30, 2005: “New satellite observations show that sea ice in the Arctic is melting faster while air temperatures in the region are rising sharply, scientists say.”

“Global Warning,” The Vancouver Sun, October 29, 2005: “Most models predict more severe weather: hotter hots, cooler colds, and more intense storms, as global thermal contrasts grow more extreme. A warmer atmosphere draws more water from oceans, resulting in bigger, wetter, more frequent storms, rises in sea level, shifts in seasons, and a chain of other climatic events.”

Fingers of parking surface runoff and biofiltration swales at Burnaby Mountain Secondary School, Burnaby.

Pedestrian and bike routes at Concord Place, Vancouver.

STRATEGIES 13

1.1.4 Site Organization, Circulation, Servicing and Open Space

Site layout responds to a development program, existing infrastructure and environmental conditions of the site. Structures should be organized close to the street to emphasize pedestrian orientation, proximity to transit, building entrances, short utility connections, safety and access to underground parking. Where sites require on-site surface parking, spaces can be integrated with outdoor amenity areas, green space and interconnected wildlife habitat to allow for multiple uses and flexibility. The components of a permeable parking lot could be removed and reused elsewhere as additional stages are added to a development or parking requirements change.

The building footprint and primary circulation routes can form the backbone of a site, working with surface drainage. In eco-effective site developments, drive aisles in surface parking and pedestrian routes form ‘ridges’ on a site. Stormwater drains away from buildings and these high points into depressions or dry wells in the lawn, rain gardens, swales or pervious parking spaces for storage, treatment of pollutants and infiltration. Utility corridors are also planned in concert with site drainage and planting design to shorten runs and avoid disturbance of natural areas on the site. Mature vegetation on a site increases property values, provides wildlife habitat and reduces the heat island effect. Natural areas also help to reduce stormwater runoff both during and after construction.

On-site circulation for pedestrians and vehicle traffic should connect with existing infrastructure in a way that enhances access through the site both visually and physically while minimizing barriers to accessibility. Links to alternative forms of transportation—public transit, bike routes and recreational amenities—and the infrastructure that supports them should be encouraged and incorporated into the circulation and open space components of the site.

Refer to LEED® SS 4.1, Alternative Transportations and SS 5.1/5.2, Reduced Site Disturbance

Broadway Tech Centre under construction, Vancouver.

The demolition and salvage of materials at the Crossroads, Vancouver.

14 STRATEGIES

1.2 Site Management During Construction

To reduce construction costs and to minimize the effect on the environment, contractors and project partners can work together to solve major issues. For example, transportation costs and the impacts of trucking of materials can be significantly reduced if green waste from site clearing and construction debris is reused on the site for landscape purposes. Also, valuable resources are not wasted or lost to landfills if materials are salvaged during demolition and recycled during construction.

1.2.1 Involvement of Contractors and Suppliers

Collaboration between the client, designers, contractors and suppliers in the initial stages of an integrated design process can produce effective solutions and cost efficiencies. When the contractor understands the design intent and spirit of the project, and has a good working relationship with the client and design team, tender prices will often be lower. The installer has much greater confidence that he or she will ‘get it right’ the first time and will receive timely approvals from site inspectors. Innovation in the landscape industry is often the outcome of meetings with the trades and manufacturers to brainstorm and develop new approaches and sustainable products for site development.

1.2.2 Construction Waste Management

In ecological site development, the project team meets with the trades to discuss recycling and construction waste strategies at, if not before, the start of construction. From site clearing to final landscaping, effective strategies can reduce the hauling of materials off-site to the landfill, the amount of waste produced and the associated transportation costs and tipping fees. Currently, demolition and site excavation debris is hauled to landfills in trucks across several municipalities, at a huge cost.

“From a global perspective, the days of inexhaustible resources, materials, and energy are rapidly ending. Interestingly, a whole market for building demolition and material reuse and salvage is changing the construction landscape, and many projects are actually making money from their waste.” Green Construction, Introducing Green Buildings & LEED® to Contractors, 2004 BuildSmart, GVRD.

Visit: the Construction Waste Management Strategies website at www.metrovancouver.org/buildsmart/construction-waste.htm.

Refer to LEED® MR Prereq 1, Storage & Collection of Recyclables; MR 2, Construction Waste Management, and LEED® MR 3, Resource Reuse.

Naturalization Strategies: salvaged soils, logs, stumps, wildlife trees, native plants and aggregate waterfront path, Furry Creek.

Truck washing and sediment control at SFU, Burnaby.

Hay bales and silt fences installed for the construction of the Canada Line at YVR, Richmond.

STRATEGIES 15

Both green waste from site clearing and non-treated timber from framing and building construction can be chipped to form a landscape mulch. A portable chipper can cut up 2 x 4s, 4 x 4s, and even 6 x 6s. Rock crushing machines can break up boulders and broken concrete with dimensions of up to one metre to form a crushed rock for subbase or ballast for underground stormwater chambers or structural soil for urban trees. Recycling greatly reduces palletizing of waste materials, and associated transportation costs including fuel, tires and brakes and the resulting dust and pollutants on the roads.

1.2.3 Soil Management

Early in the design process, a geotechnical engineer or hydrologist should investigate site conditions and determine infiltration rates and engineering constraints. Soils can be tested for structural integrity as required for building foundations and pavement structures. It is beneficial to the environment and to the project budget if the hauling of material off-site can be avoided or greatly reduced.

This soil strategy may not be possible at urban sites where soils may be contaminated or the building and underground parking may cover the entire site. The strategy remains important on greenfield sites where soils are often removed or degraded significantly during construction. At greenfield sites, soils, chipped green waste and other organic components (such as forest duff and detritus) should be disturbed as little as possible and be stored on-site. Exposed soils should be covered with tarps to avoid erosion and to keep the soils dry for blending and reuse in the landscape. Forest duff from wooded sites may contain a seed bank that can help to regenerate sites with native plants, thereby reducing the cost of new planting and imported growing media.

Woody material can be chipped for use as mulch that benefits plant development through moisture retention, thermal insulation and reduced soil erosion. Larger woody debris consisting of stumps and logs as well as wildlife trees (snags) can be ‘planted’ vertically in the ground to provide significant wildlife habitat.

1.2.4 Erosion and Sedimentation Control

Control of soil erosion is required by all Municipalities in Metro Vancouver, the Department of Fisheries and Oceans Canada (DFO) and the B.C. Ministry of the Environment to mitigate negative impacts on water resources and air quality. General site planning techniques include using development setbacks from streams and aquatic areas and protecting on-site trees and understory vegetation. Wind-blown dust from exposed sites and trucks can

“Waste materials and subsoils that do have to be hauled away can utilize the same trucks that deliver new materials such as construction aggregates.” Pat O’Brien, Holland Landscapers.

The Burnaby Mountain Restoration Area project transforms a former construction staging site for SFU into parkland. The landscape construction includes green space restoration, revegetation of overburdened soils and wildlife habitat enhancement. Sediment control includes silt fences and the covering of large stockpiles of excavated soils and large temporary slopes with anchored polyethylene sheeting. Interceptor and cut-off ditches are designed with check dams (filter berms) installed 15m on centre. Earthworks, grading and planting soil placement is terminated during periods of heavy rainfall.

The revegetation includes fall planting with groups of indigenous trees and shrubs and hydroseeding with quick-germinating annual ryegrass for erosion control. In the spring, as the annual ryegrass dies off, the site is seeded with a mix of native wildflowers and grasses to attract foraging deer.

16 STRATEGIES

also negatively affect air quality.

Erosion and sedimentation control techniques that are required prior to construction, and to be maintained during site development include:• earth dikes to divert surface run-off volumes from disturbed areas into basins or traps• excavated sediment basins or sediment traps contained by stabilized soil embankments to slow water release (temporary storage) and allow settlements of sediment• silt fences constructed with posts and geotechnical fabric to reduce and remove sediment• wheel washes and rumble strips for trucks• balanced cut and fills to minimize transportation of material to or from the site.

1.2.5 Hydroseeding, Revegetation and Protection of Soils

Hydroseeding with fast-growing grasses can temporarily stabilize soils. As well, mulching with hay, grass, wood chips or straw or using gravel on the soil surface can provide cover and hold soils in place. Disturbed site areas should be shaped and contoured in conjunction with plantings to minimize the concentration of run-off. Slopes subject to erosion may require protection with hydro-mulch, erosion control matting (straw/coconut fiber blanket), straw-cover or 75mm minus clear crushed rock.

Native wildflowers and grasses as well as trees and shrubs can permanently stabilize exposed soil and slopes, attract deer, birds and invertebrates, and out-compete invasive species without the use of herbicides. Use of indigenous plants often eliminates the need for watering except during establishment maintenance.

Establishment or short-term maintenance includes temporary watering, mulching and organic-based fertilization as required for germination of hydroseeded grasses, wildflowers, trees and shrubs. Long-term maintenance involves any necessary repairs or replacement of the erosion control facilities and monitoring of the quality of water flowing off the site for at least two years.

Refer to the Erosion and Sedimentation Control webpage in the GVRD website at www.metrovancouver.org/buildsmart/ErosionSedimentationControl.htm.

See also LEED®SS Prereq 1, Erosion & Sedimentation Control

The streetscape with permeable pavers, landscape swales and underground storage/infiltration systems, forms part of an interconnected treatment chain, at UnverCity, SFU.

Rainwater source controls such as rain gardens, landscape swales and absorbent landscapes provide for micro-storage upstream of storage facilities and create a central focus and amenity area for the Portrait Homes development in Silver Valley, Maple Ridge.

STRATEGIES 17

1.3 Rainwater Management and Biofiltration

The objective of rainwater management (SWM) is to replicate, where possible, the pre-development water quality, discharge and hydrology of a site. It is possible to restore natural water flows by a combination of landscape, biological and/or engineered devices or integrated systems that eliminate runoff, increase on-site infiltration and remove contaminants. Source controls such as rain gardens, green roofs, cisterns, porous pavements and absorbent landscapes provide for micro-storage upstream, act as replacements for storage facilities or are installed as an interconnected system comprising the same basic chain of landscape features associated with natural stream systems. Where sites have permeable soils and porous pavements, water will infiltrate into the earth and recharge groundwater resources.

There are numerous strategies for the storage, infiltration and biological filtering of stormwater. • Rainwater harvesting is the collection of water for storage and reuse in the building or the landscape. • Porous pavements and free-draining aggregate base courses allow run-off to infiltrate below the surface where water can be mechanically and biologically filtered the way it is in natural systems. • Vegetated swales, rain gardens and absorbent landscapes are planted controls that filter sediments and pollutants from stormwater. • Larger engineered systems and storage facilities such as constructed wetlands can be designed to mimic the properties of natural wetlands. • Detention ponds, infiltration trenches and basins are also effective for storing stormwater and promoting infiltration.

The concept of ‘interconnected treatment chains’ is defi ned as water fl owing from one stormwater facility to another such that collection, treatment, storage and/or infi ltration occur in series. For example, run-off from the street or surface parking lot fl ows in shallow channels into a permeable or open grid paving system installed over underground storage tanks, which overfl ow only during larger storm events into open watercourses and detention ponds.

Refer to the Stormwater Source Control Design Guidelines 2005, GVRD, April 2005(See www.metrovancouver.org/buildsmart/pdfs/fi nalstormwatersourcecontrol.pdf.) Refer to the Water Balance Model for B.C. website at www.lanarc.ca/balance/pdf/SustainabilityNow.pdf or www.waterbalance.ca

Refer to LEED® SS 6.1 / 6.2, Stormwater Management.

City of Vancouver rain barrel.

18 STRATEGIES

1.3.1 Rainwater Harvesting

On urban sites, cisterns, vaults and rain barrels have universal application for storage of rainwater where space is limited, especially in higher density developments. Roof leaders, channels along pavement and raised storm drains in the landscape can be designed to collect rainwater. The harvested rainwater can be used for non-potable water purposes such as irrigating the landscape, toilet and urinal flushing, custodial applications and operation of building equipment.

The Municipalities of Vancouver, Burnaby, New Westminster, Richmond, Coquitlam and Delta offer a residential-sized rain barrel that holds 341 litres. The half-cylinder barrel is designed to sit flush to the wall of a building, house or garage. Green buildings in the City of Chicago, Illinois use corrugated galvanized cisterns adopted from the Midwest’s agricultural storage facilities. Saltspring Island and other dry regions of B.C. where summer water restrictions occur encourage the use of underground cisterns, tanks and roof-mounted ‘water towers’.

Costs: An integrated approach to rainwater management can reduce overall site development costs by eliminating or reducing the engineer requirements for catch basins, underground piping systems, large storage systems and downstream treatment. While conventional paving materials are less expensive than conservation alternatives, porous materials can help total development costs go down, sometimes as much as 30%, by reducing conveyance and detention needs.

“Swale conveyance is cheaper than pipe systems, by some claims as much as 80%.Perhaps the most signifi cant theme gleaned from the literature is that, by combining multiple tools, such as clustering with native landscaping, bio-swales, and other practices, deeper cost savings can be achieved from the resulting opportunities to downsize the infrastructure. Across ten case studies examined here, holistic conservation design treatments saved an average of 36% over conventional practices.”

Northern Illinois Planning Commission, Changing Cost Perceptions — An Analysis of Conservation Development. (See www.nipc.org/environment/sustainable/content.htm#Changing%20Cost%20Perceptions).

Useful References:Waterscapes; Planning, Building and Designing with Water, by Herbert Dreiseitl et al.New Waterscapes; Planning, Building and Designing with Water, by Herbert Dreiseitl et al.

A parking lot with biofiltration swales and interpretive signage, Water Pollution Control Laboratory, Portland, Oregon.

Ecological development on a brownfield site, Oregon Museum of Science and Industry, Portland, Oregon.

Permeable unit pavers at UniverCity, SFU, are designed for stormwater management, both as a mechanical and biological filter for pre-treatment, and to control the rate and quantity of run-off. In the joints and in the void spaces of the no-fines gravel below, naturally occurring microorganisms digest hydrocarbons from car oils. The oil no longer exists as a pollutant because only carbon dioxide and water remains.

STRATEGIES 19

1.3.2 Porous Pavement

Porous pavements are structural paving systems that support the weight of a vehicle and allow water to infiltrate into the ground and recharge aquifers, thus reducing stormwater run-off. Microbiotic organisms that naturally live in the gravels and soil below the paving surface consume hydrocarbons and other pollutants running off vehicular surfaces.

Types of porous pavement include pervious concrete, permeable unit pavers, open-grid paving and aggregate surfaces. The pavements and free-draining aggregate base courses allow runoff to infiltrate below the surface and provide mechanical and biological water filtering while requiring little maintenance. Porous pavements and permeable surfaces operate in the same manner, but are typically maintained by a vacuum sweeper twice a year (in spring and fall) to avoid potential clogging. Power washing is not recommended for porous paving as it can wash out the aggregate joints on permeable pavers and break down the adhesion of pervious concrete.

1.3.3 Vegetated Swales and Biofiltration

Vegetated swales, landscape swales or bio-swales filter sediment and pollutants from stormwater. Vegetated swales are typically long, linear and run parallel to a road or parking lot to collect stormwater sheeting off paved surfaces. They are considered to be safer and more aesthetically pleasing than a traditional ditch and present a more gradual slope in order to slow down stormwater run-off and allow for more contact with the ground and vegetation. Swales are often used in combination with underground infiltration trenches and stormwater basins or wetlands. By slowing the speed of run-off and increasing both the infiltration rate and contact time with vegetation, these smaller source controls provide pre-treatment to take up harmful contaminants in stormwater run-off, prevent clogging of basins or trenches and can reduce the size of engineered stormwater infrastructure. Moisture-tolerant plants grow best in a structural-type engineered growing medium that filters run-off and encourages infiltration.

Another application of this strategy is in the use of reinforced grass paving. Grass paving products incorporate biofiltration right into the parking lot itself. While not generally suitable for high-traffic areas, grass paving is ideal for overflow parking or fire lanes. For success in the Lower Mainland, reinforced grass paving for parking lots should be engineered, irrigated, fertilized and maintained to a high standard, equivalent to the level of care required for a professional sand turf sports field. As in other forms of porous paving, an open joint pavement system absorbs oil and hydrocarbons dripping from

Refer to: Porous Pavements, Bruce K. Ferguson, CRC Press, Athens, GA, 2005, ISBM 0-849326702.

Rain gardens at Clarendon Street, Vancouver.

Existing forest, Burnaby Mountain.

20 STRATEGIES

parked cars. These substances infiltrate into the ground where they are consumed by microorganisms living in the soil below the surface. Additionally, porous pavement installed over structural soil provides ample rooting space for urban trees to grow to full size.

1.3.4 Rain Gardens

Rain gardens are often designed as a focal element in the urban landscape to celebrate rainwater and incorporate this natural process as a visual component of a development’s stormwater infrastructure. They are often wider than a vegetated swale but shorter in length. Rain gardens are often designed for higher density urban sites, replacing raised planting beds and adding a functional and visually pleasing element to rooftops or in bulges along a streetscape where a larger and lower landscape area offers storage capacity. They can feature a colourful selection of moisture-tolerant native and ornamental plants, as well as shade trees planted along edges of a depressed rain garden.

1.3.5 Absorbent Landscapes

Absorbent landscapes allow rainwater to soak into the ground and temporarily store stormwater, such as in an existing forest. Absorbent landscapes often are dished with gentle side slopes to retain a larger area of water, at a shallower depth. The landscape functions as a filter and retains soil moisture for a longer period of time then a more traditional raised planting bed. Absorbent landscapes do not usually contain irrigation systems that use potable drinking water.

A 450mm depth of sandy soil with +/- 15% organic matter (by volume) and 50mm depth composed surface mulch is ideal for temporary rainwater storage. Providing flush curbs and drop curbs will allow runoff from paved surfaces into the infiltration swales, rain gardens and natural vegetated areas. Absorbent landscaping also comprises the conservation of undisturbed soil and existing vegetation including forest trees, understory plants and meadows. An undisturbed forest floor typically does not produce surface runoff during storm events.

Refer to the plant list provided in Stormwater Source Control Design Guidelines 2005, GVRD, April 2005 (see www.metrovancouver.org/buildsmart/pdfs/fi nalstormwatersourcecontrol.pdf).

Refer to: Landscape Guide to Canadian Homes, CHMC, 2004. (See Part 2, Let Stormwater Soak into the Ground, p46.)

Constructed wetlands and stormwater retention pond at Fraser Glen, Surrey.

D-Rain Tank for underground storage (see www.funkenorthamericaltd.com).

STRATEGIES 21

1.3.6 Underground Storage Systems

Infiltration trenches, underground attenuation chambers and granular basins are engineered products used to encourage subsurface infiltration and temporary storage (both long- and short-term) of stormwater run-off. Infiltration trenches or filtration units are underground systems located near buildings or streets that capture run-off from impervious built surfaces and release it slowly into native soils or downstream systems. Run-off is collected and directed through a silt trap manhole prior to entering the underground storage tank for attenuation and/or infiltration. Underground storage systems can be filled with 75mm ballast or modular polypropylene units, wrapped in geotextiles and aggregates, and can handle vehicular loading of up to 30t/m2. Permeable paving systems can be installed on top of infiltration trenches or modular underground storage systems. This effectively infiltrates all of the run-off that would have normally resulted from a conventional paving system.

1.3.7 Constructed Wetlands and Ponds

This particular method of stormwater management has been around for many decades. Constructed basins or ponds can store large volumes of stormwater, but require drainage within 72 hours to maintain aerobic conditions, avoid mosquito breeding and maintain capacity for the next storm event. Planting the basin edges with riparian plants provides additional biological filtration. Traditionally, basins by themselves have consumed large areas of developable land and became liability concerns and eyesores. However, when integrated into a larger ecologically based stormwater management plan, they can be much smaller and located in several areas on a site or in a neighbourhood as part of the open space plan.

Constructed wetlands are larger engineered systems that are designed to mimic natural wetland treatment properties. Detention ponds capture large quantities of stormwater, control peak flows and allow pollutants to drop out before release into a stream or water body. It is preferable to treat stormwater at the source (where the raindrop hits the pavement or roof) and in small areas throughout the development. Avoid large water storage facilities that can become a potential liability and/or use up valuable real estate.

A fence or low barrier such as a rustic timber rail is recommended around the perimeter to discourage unattended access to a pond. A diverse mix of wetland trees, shrubs and riparian plants provides wildlife habitat and aesthetic value. Access for collection of wetland plants, sediment, and debris may be required to monitor contaminants on an annual or “five-year” basis.

Burnaby Mountain School, Burnaby.

22 STRATEGIES

Burnaby Mountain Secondary School is located near to Stoney Creek, which is home to several species of fi sh including endangered Coho salmon. The site features planted landscape swales in the parking lot which fi lter the stormwater that has picked up contaminants from the impervious asphalt pavement. Placing only wheel stops and omitting continuous curbs from the design plans causes run-off to fl ow directly from paved surfaces into infi ltration swales. The biofi ltration swales, in combination with raised catch basins, convey overfl ow run-off to ponds at each end of the site. In the landscape swales, native “drought and moisture-tolerant plants” remove contaminants (hydrocarbons), and canopy trees shade the parking lot. The biofi ltration ponds contain grasses, reeds and shrubs that clean the water before it fi lters into Stoney Creek.

Refer also to www.greenbuildingsbc.com/new_buildings/case-studies.html.

Refer to: Sustainable Landscape Construction, A Guide to Building Outdoors, Thompson and Sorvig, 2000. Water Pollution Control Laboratory, Portland Oregon, p16.

Cistern at the Centre for Green Technology, Chicago.

Salmon-bearing stream in the North Shore mountains.

STRATEGIES 23

1.4 Water Efficiency

Water is a precious resource in many countries around the world and elsewhere in North America. It is becoming more important every day. In the Metro Vancouver, treated drinking water is used for all purposes, including outdoor landscaping to maintain a lush ‘green’ appearance during the spring, summer and early fall. Water has always been plentiful; therefore, we have never conserved the resource. A highly maintained ornamental landscape consumes large quantities of water, chemical fertilizers, pesticides and energy. The machines required to maintain such ornamental landscapes create air and noise pollution. Waterwise gardening is a new aesthetic choice offering four seasons of colour and interest at a much lower cost, both economically and environmentally.

Refer to LEED® WE 1.1 / 1.2, Water Effi cient Landscaping.

One challenge of encouraging water conservation in the region is the low cost of potable water and an apparent abundant supply. Metro Vancouver is among the lowest-cost suppliers of water in North America, but water treatment and distribution come at a relatively high cost to taxpayers. However, with our coastal climate, simple landscape measures are available to conserve water and provide a landscape with a wide variety of colour, foliage and seasonal interest. For instance, rainwater can be harvested off roofs or paved areas, then filtered and used for outside irrigation needs. Native plants and hardy ornamentals should be selected to provide the right landscape function with low water requirements: the ‘right plant for the right place.’ Use rock or decomposed mulch to retain soil moisture and invert planting beds to collect rainwater for landscaping and trees.

The technology is available to design and build a building to be ‘off the grid’ without the need for municipal water. An example of such a building is the proposed Centre for Interactive Research in Sustainability (CIRS) at the Great Northern Way Campus in Vancouver.

For more information visit www.gnwc.ca/Content/GNWC17.aspx - 12k. Changes to the building codes may be required to facilitate the use of rainwater for drinking water. Only minor fi ltration of rainwater from rooftops may be required to make it potable. Rainwater will be harvested for use inside the CIRS building for fl ushing toilets, janitorial cleaning and operating equipment, and for use outside as landscape irrigation.

Native xeric plants, Coastal B.C.

Rain barrel, City of Vancouver (see w w w . c i t y . v a n c o u v e r . b c . c a / e n g s v c s /solidwaste/grownatural/rainbarrels.htm).

Photo by Helen Goodland

Waterwise gardening with attractive drought-resistant species.

24 STRATEGIES

1.4.1 Plant Selection and Waterwise Landscaping

Drought-resistant native or hardy ornamental plants add colour and lasting value at minimal maintenance cost to a project. Attractive waterwise and xeriscape techniques include an engineered growing medium with sufficient organic matter with a 50 to 75mm layer of decomposed mulch or crushed rock to maintain soil moisture. Minimize the use of traditional, well-maintained lawns that can consume large quantities of water, chemical fertilizers and herbicides. Avoid specifying invasive plants such as English-ivy, broom, baby’s breath, variegated lamium, Japanese Knotweed, loosestrife, several varieties of bamboo and numerous other aggressive species that can spread into natural areas.

1.4.2 Landscape Irrigation

Stormwater can be collected, stored and reused for non-potable uses including supplemental water for a site’s landscape or green roof. If supplemental irrigation is required, use high-efficiency irrigation heads, micro-spays or drip emitters. Avoid the use of potable water except for temporary watering during 12 or 24 months of establishment maintenance, or during periods of extreme drought.

Design the landscape and grade site surfaces to create pockets where water will naturally collect. Use rain barrels, underground cisterns and/or storage tanks to store non-potable water. Because landscape watering is usually required only on sunny days, consider a solar-activated pump. Graf, an innovative manufacturer from Germany, offers several rainwater harvesting systems, infiltrators, cisterns and pumps that may soon be available in North America. Visit www.graf-online.de/index.php?lang=en&id=20001.

Refer to:

• the Field Guide to Noxious and Other Selected Weeds of British Columbia (www.agf.gov.bc.ca/cropprot/invasiveplant.htm)

• Pacifi c Northwest Native Plants Suitable for the West Coast Garden, a list by N.A.T.S. Nurseries, of plants available at ‘leading’ garden centres in Metro Vancouver

• the N.A.T.S. Nursery Ltd. website at www.natsnursery.com for descriptions of common native plants and their habitats

• the Native Plant Society of British Columbia website at www.npsbc.org

• the Waterwise Gardening website at www.gardenwise.bc.ca/gardenwise/waterwise.lasso

• Metro Vancouver’s waterwise gardening guide that includes a list of drought-resistant plants for use in the region (see www.metrovancouver.org/water/pdfs/WaterwiseGardeningv052005.pdf)

Permeable pavers around a heritage tree, the SF Group.

Urban trees in pavers at Granville Island, Vancouver.

STRATEGIES 25

1.5 Urban Heat Island Reduction

Urban heat islands are urban centres and industrial areas that are hotter than the surrounding landscape. The higher temperature is primarily caused by the release of heat radiation absorbed from sunlight by dark paving and finishing materials such as asphalt, concrete and tar and by the lack of vegetation.

Urban heat islands tend to increase local ambient temperatures, change local microclimates, increase energy use (as HVAC systems are used to counteract the increased temperatures) and increase emissions of contaminants that make up photochemical smog.

1.5.1 Street Trees and Shade on the Site

Trees supply shade for impervious surfaces such as parking spaces, roadways, sidewalks, plazas and other paved surfaces. Big shade trees, green roofs and landscape planting provide biomass, reduce ambient temperature, clean the air by trapping particulates and carbon dioxide and mitigate the urban heat island effect through evapotranspiration. The City of Seattle’s Resource Guide for Sustainable Development identifies strategies for the South Lake Union neighbourhood that address multiple ecological functions. The strategies include a ‘big tree neighbourhood’ with large double rows of canopy trees along green streets, structural soils, porous pavements, and vegetated roof systems. The City’s primary objective is to reduce stormwater flows. Other objectives include conserving energy by reducing ambient temperatures, offsetting CO2 emissions, reducing potable water use and improving the quality of life in the neighbourhood. Meeting the objectives mitigates the effects of urban heat islands.

Big trees are good for shopping. “Shoppers claim they will spend more time in a retail district having trees.” Trees Are Good for Business, Chapter of the International Society of Aborticulture, Portland, Oregon, June 2005.

Big Trees In Permeable Pavement and Structural Soil “is a revolutionary new way to integrate healthy ecology and thriving cities: living canopy above, the city’s traffi c on the ground, and living roots below.” Pervious Concrete Pavements, Paul D. Tennis, Michael L. Leming & David J. Akers, c. 2004, Portland Cement Association, Skokie, IL

Refer to www.seattle.gov/dpd/GreenBuilding/SustainableCommunities/Resources/. Refer to LEED® SS 7.1, Heat Island Effect: Non-Roof.

Reinforced grass paving at the Crestwood Corporate Centre, Richmond.

For the practicality of open grid grass paving for parking lots, refer to www.funkenorthamericaltd.com and www.invisiblestructures.com/Med&tech/WhitePapers/ParkingFreq.pdf.

For general information and specifi cations, refer to the Interlocking Concrete Pavement Institute’s website at www.icpi.org.

26 STRATEGIES

1.5.2 High Albedo Paving Materials

Albedo is a measurement of how reflective a surface is. Lighter paving materials with a higher reflectance and/or open-grid pavements have a high albedo and reduce heat absorption. Darker materials and impervious cover have a low albedo and an increase in heat absorption. For example, the Douglas Border Crossing at Highway 99 in Surrey will feature vehicular unit pavers that will be lighter in colour for increased reflectivity and reduced heat absorption. Titanium dioxide is an integral pigment added to the cement mix to lighten concrete pavers. These microscopic particles remain shiny and light over time. Further research and testing is required for high reflectance and open grid paving in Metro Vancouver.

Care must be taken regarding to highly reflective surfaces for driving and walking as they may irritate or hinder a person’s vision. As we age, our eyes are often unable to adjust to extreme illumination and a bright, highly reflective paving material might represent a barrier to some segments of the population.

1.5.3 Green Facades and Living Walls

Green walls can lower the energy demand for cooling and heating, provide air filtration and extend the exterior wall system’s service life by protecting the wall from UV degradation.

Vegetation on exterior walls has the potential to mitigate the heat island effect by evaporative cooling and by filtering out dust and pollutants in the air. In Japan, green walls are considered more important than vegetated roofs on tall buildings because the ratio of wall area to roof area is much greater. There are two types of green walls: • green facades • living walls

Green facades feature vertical structural systems that support climbing plants on the building exterior. Climbers and vines are supported by stainless steel cables, webbing or metal grids and grow up from grade or planters. In 2006, green screens or cable systems cost in the range of $150 to $250 per vertical square metre installed.

Living walls are a much more intensive and complex application. They are

Visit www.greenscreen.com or www.jakobstainlesssteel.com

Living Wall (Type ‘B’ ) (Verdir Systems)

made up of plants rooted in fabric pockets or pre-vegetated panels, supported by a vertical frame. Living walls or vertical gardens add thermal mass to a building and are based on the principles of hydroponics for moisture and nutrient supply. Structural weight, moisture retention, nutrient supply and water distribution are important design considerations. Vegetated walls require a much higher level of maintenance than climbers on a vertical frame. In Toronto, Quality Air Solutions markets the ‘bio-wall’ designed for biofiltration of interior environments, including the removal of volatile organic compounds (VOCs).

1.5.4 Green Roofs

Green roofs are engineered vegetated roofing systems that replicate the natural environment by absorbing rainwater and carbon dioxide, and by releasing water and oxygen back to the atmosphere through the processes of evapotranspiration and photosynthesis. Green roofs offer multiple environmental benefits including reducing the heat island effect, conserving energy by decreasing ambient temperatures, offsetting CO2 emissions, attenuating noise, providing wildlife habitat and offering an urban amenity. Properly constructed green roofs extend (double) the life of the waterproof membrane by protecting the roof from UV degradation. The City of Toronto has a new green roof website that reports on the benefits for stormwater management, energy consumption, reducing urban heat island effect, air quality and reducing emissions.

The Parkade for the River Rock Casino features a vertical structure to support vines that shade the building and filter dust from the air. The green facade features three species of climbers (clematis, honeysuckle and golden hops or Humulus lupulus 'Aureus') rooted in the ground and supported by wall-mounted trellises. At River Rock, an inexpensive chain link mesh was installed on a galvanized tubular steel frame bolted to the concrete parkade structure. In addition to supplemental watering in the summer, maintenance of the climbers includes biannual pruning.

Extensive green roof/eco-roof on the RCMP Justice Building, Sechelt.

Green wall panels for the Vancouver Aquarium’s, Aquaquest Learning Centre

Visit www.naturaire.com

Visit: www.toronto.ca/greenroofs/fi ndings.htm

STRATEGIES 27

Intensive green roof for the Bentall Development at the Broadway Tech Centre, Vancouver.

Multiple green roofs and rooftop gardens proposed by ONNI Developments for Suter Brook, Port Moody Town Centre .

28 STRATEGIES

There are two general types of rooftop garden systems: extensive and intensive. An extensive green roof system features lightweight growing media, usually between 50 to 150mm (2” to 6”) in depth, installed over drainage and/or moisture retention layers on top of a root barrier and waterproof membrane. Pre-cultivated vegetation blankets or pre-grown modules are also available for sloping roof systems. Minimal ongoing maintenance is required unless a more ornamental or manicured appearance is preferred.

A variation of the extensive green roof—locally called an ‘eco-roof’—can be planted with native or hardy sedums, grasses and/or wildflowers that can, once established, form a self-sustaining ecosystem requiring little or no maintenance or watering. Establishment maintenance including temporary irrigation, fertilization and weeding during the first 12 to 18 months is key to successful plant coverage and performance. (See also Part 3, Sustainable Technology Series, Case Study #1, Extensive Green Roof.)

Intensive or semi-intensive green roofs are often known as rooftop gardens or landscapes over structure. Intensive green roofs often have a greater emphasis on aesthetics and can support trees, shrubs and lawns that require more intensive maintenance and landscape irrigation. Variations of intensive roofs will accommodate urban agriculture and/or plantings to support biodiversity and increased wildlife habitat. Intensive roofs may be combined with eco-roofs.

Green roofs can also offer a place for innovative wastewater technologies such as grey water treatment.

Green roofs can reduce the ‘design energy cost’ for mechanical cooling systems and minimize thermal gradient differences between developed and undeveloped areas.

Refer to “Green Roof Research in British Columbia — An Overview,” by Maureen Connelly, British Columbia Institute of Technology, Co-chair, GRHC's Research Committee, available from: www.greenroofs.org, proceedings of the Third Annual Greening Rooftops for Sustainable Communities Conference, Awards and Trade Show Washington, 2005.

Extensive green roof at the Green Operations Building, White Rock, BC. Photovoltaic (PV) systems function more efficiently if they are placed on a green roof than on a conventional roof surface. As well, the shading provided by the PV’s creates a variation in microclimate that supports a greater diversity of plants on the roof.

Photo by Roger Burt

Roof retrofit - green roof at Mountain Equipment Co-op, Toronto, ON.

Photo by Lorraine Johnson

Wildlife and wild flowers on green roof,JAS Robertson Building, Toronto, ON.

Photo by Beth Anne Currie

STRATEGIES 29

1.5.5 White Roofs

Non-vegetated roofing materials that are light in colour have a high albedo and may reduce heat absorption; however, the solar radiation is reflected back into the atmosphere. Reflective roofing can lower roof surface temperature by up to 55ºC, decreasing the amount of heat transferred into a building and reducing energy costs. For example, thermoplastic polyolefin (TPO), available as a single-ply membrane, is initially white for high reflectance; however, it requires washing to maintain its whiteness. White roofs are not used along flight paths in Richmond as they temporarily blind the pilots approaching the airport. Further research and monitoring in Metro Vancouver is required for this technology.

Green Roof Resources (see also Part 3, Sustainable Technology Series, Case Study #1, Extensive Green Roof):

• www.greenroofs.org, Green Roofs for Healthy Cities, North America

• www.greenroof.se, International Green Roof Institute

• www.greenroofs.com, a green roof directory of roofi ng manufacturers, suppliers of green roof products and resources

• www.greenroof.bcit.ca, BCIT Green Roof Research Facility and CAGRT

• www.gnla.ca/library.htm, “Green Roof Policy: Tools for Encouraging Sustainable Design”, by Goya Ngan, 2004, Landscape Architecture Canada Foundation.

• Refer to LEED® SS 7.2, Heat Island Effect: Roof.

Refer to the Energy Star websites at www.energystar.gov and www.carlisle-syntec.com/index.cfm?act=Green_energystar. If a built-up roof (BUR) system is selected, consider a 75mm layer of white marble as continuous ballast. White roofs and green roofs can be combined for LEED® credit 7.2.

Trellis/lightweight structure supporting climbing plants at the Baptist Housing Society’s, Shannon Oaks, Vancouver

30 STRATEGIES

1.5.6 Combining Rooftop Technologies

On high-density urban sites, intensive green roofs, ‘green screens’ and permeable pavers can be combined as modular systems that allow the flexibility to change over time and access to the roofing membrane. Trellises and lightweight structures support climbing plants, without the weight or wind loading of trees. ‘Green screens’ can be very attractive attached to walls and mounted as freestanding baffles for shading, screening and reducing the visual impact of roof infrastructure (consider the views from buildings), without the weight required to support trees.

Low (200 to 300mm high) ‘curb walls’ with the soil sloping up in berms offers a softer, garden-like, appearance. If care is taken to not compromise the roof membrane, a smaller modular stack wall system, also permeable, can be installed over a continuous drain mat to allow for the creation of garden plots. Children’s play equipment, tool sheds and patio amenities can be mounted on roof decks, well away from edges and surrounded by resilient tiles. Shading and protection from the wind—whether incorporated in the initial design stages or as retrofits to an existing building—are necessary for a usable roof deck.

Interpretation kiosk with habitat enhancement, Furry Creek, B.C.

The Granville Island redevelopment features both salvaged buildings and materials.

Photo courtesy of CMHC.

STRATEGIES 31

1.6 Materials, Resources and Maintenance

As the basic building blocks of any development project, the materials used to construct the project are indicative of its quality and its commitment to sustainable development, design and construction. Because materials represent some of the most visible and long-lasting symbols that the users of a development will experience and identify with, it is important that they illustrate and reinforce both the function and the ideological goals of ecological design established in the earliest stages of site planning and development.

The use of high quality, locally salvaged material, harvested timber, native plants or quarried granite can establish an important connection to place that can ground a project in a local and regional context in a way that exotic or imported materials cannot.

1.6.1 Reuse of Materials

The overall goal of reusing materials is to decrease the environmental impact and cost associated with the extraction and processing of virgin resources. The salvage and reuse of on-site landscape and building materials will reduce the demand for new materials and therefore reduce project costs. It will also minimize demolition and construction waste. Salvaged materials can include boulders, interior furnishings, structural timbers, granular sub-base (excavated materials or crushed concrete/asphalt), landscape fill, architectural detailing, broken concrete sidewalks (for retaining walls or permeable pavement) and bricks (for pavement).

Refer to LEED® MR 3, Resource Reuse

A landscape management strategy and habitat enhancement program for forested greenfield sites can reuse most of the non-marketable trees and native materials on site. Cover salvaged materials with tarps for protection against rain, wind-blown weed seeds, contamination, compaction and erosion. Transplant site trees where possible and salvage smaller plants such as ferns, shrubs and aquatic plants in pots for replanting. The use of a native plant nursery to salvage and re-grow indigenous plant material can be cost effective.

Recycled glass in gabian walls, at GALABA 2004, Germany.

Salvaged bricks reused in landscaping.Photos by Helen Goodland

Reuse of buildings, materials and artifacts at Granville Island.

Photo courtesy of CMHC.

32 STRATEGIES

Permeable landscapes and site surfaces are based on a ‘kit of parts’ made up of durable long-lasting materials that allow for maximum flexibility. Modular site components are reusable and adaptable to changes in the site’s use and building program. Salvaged pavers and broken pieces of concrete can be reused in a variety of paving applications. Metals can be artfully designed, re-fabricated and painted to look like new material at a fraction of their original cost.

The use of salvaged and refurbished materials in new building projects extends the life of materials and can reduce upfront costs of construction materials. Materials used in new construction account for a large and expensive portion of our use of natural resources, including 40% of raw stone, gravel and sand and 25% of virgin wood.

1.6.2 Recycled Materials for Construction

Landscape products having recycled content include growing media, salvaged lumber, plastic open-grid paving and plastic products, as well as metals, concrete and masonry. Consider materials that are either biodegradable or that can be ‘up-cycled’ in the future for a higher use. For example, EcoSmartTM concrete is manufactured by substituting cement with a maximum percentage (50%+) of supplementary cementitious materials (SCMs) such as fly ash (a waste product of coal burning power plants) determined by concrete strength and other construction requirements.

Recycled forestry and food waste can be composted and blended for growing media. In Metro Vancouver, this organic matter is often made up of aged hemlock and fir bark blended with food compost, coffee grounds, green waste and/or aged mushroom manure, active with micro-organisms. Avoid the use of peat moss extracted from peat bogs and environmentally sensitive areas.

The new edition of the B.C. Landscape Standard will provide much more detail in relation to landscape standards for construction and maintenance. Topics such as ‘growing medium’ can be referenced in landscape architect’s specifications for contract documents. The B.C. Landscape Standard will be published by the B.C. Landscape & Nursery Association (BCLNA) and the B.C. Society of Landscape Architects (BCSLA).

Refer to www.ecosmart.ca.

Refer to LEED® MR 4, Recycled Content.

Refer to the Freecycle website at www.freecycle.org. Freecycle is an email list where people give away things that they no longer need for free.

“The total environmental benefi ts of material recycling are generally less than that of material reuse because of the environmental burdens associated with recyclable materials collection, transport and processing into new products. Therefore, reuse of building materials (MR Credits 1 and 3) is preferred over recycling when possible.” LEED® Reference Package, LEED® Canada-NC, Version 1.0, December 2004.

Local manufacturer, Frances Andrew bike rack (see Site Furnishings at www.francesandrew.com).

Recycled plastic lumber in park bench (see Wishbone Industries at www.wishboneltd.com).

STRATEGIES 33

1.6.3 Regional Materials

The majority of soft landscape materials for projects in the lower mainland can be supplied locally or within an 800 km radius (500 miles) - allowable distance to achieve LEED® credit MR5. LEED® provides a relaxation for products and materials arriving by rail; the allowable distance for the MR5 credit is extended to 2400km (1500 miles). Using local materials reduces the environmental impacts and the costs of trucking. These include: nursery stock, growing media, mulch, drainage aggregates, lumber and other building materials. Quality metal structures and furnishings can be manufactured or fabricated locally at a lower cost.

Refer to LEED® MR 5, Local / Regional Materials.

1.6.4 Local Manufacturers

It is beneficial to specify a local manufacturer or supplier in order to support the local economy and to reduce the cost of transporting materials. But if a particular product or technology isn’t yet available locally, don’t stop there. Encourage your local supplier to research, adopt, and develop new eco-products, and to create custom fabrications for unique regional applications. There may, of course, be proprietary constraints for some technologies not available locally. However, every effort should be made to make sustainable products and technologies available and manufactured locally.

Metro Vancouver offers an online database of locally sourced products at www.metrovancouver.org/BuildSmart/Apps/productSearch.aspx.

1.6.5 Organic Landscape Maintenance

A traditional manicured garden requires an expenditure of energy, water and chemicals to maintain its ‘well-groomed’ appearance. Alternatively, organic landscape maintenance is the outdoor equivalent of ‘Green Housekeeping’ (use of biodegradable or sustainable products). Planting the ‘right plant for the right place’ is the best way to ensure a healthy productive landscape with minimal care. Maintenance to ensure plants can become established in the critical first year helps control erosion, facilitates bio-filtration of stormwater, and maximizes the performance of green roofs and landscapes.

“If you’re not buying recyclables, you’re not recycling!” Mark Roseland, Toward Sustainable Communities, 1998. Guide to Green Buildings Resources, Green Buildings BC — New Buildings Program. (See www.greenbuildingsbc.com/new_buildings/resources_guide/6.0_epr_materials.html.)

Green Roof mainenance during 12 month establishment, Sechelt.

Urban tree maintenance at Granville Island.

34 STRATEGIES

Compost gardening and organic integrated pest management (IPM) are the cornerstones of an organic or sustainable maintenance strategy. For instance, leaves and clippings can be collected and composted onsite. The resulting composted mulch is spread over the landscape during the next spring and summer. In more natural areas, leaves can be simply left where they fall. Avoid the use of mowing and leaf blowing equipment that consumes energy and produces air and noise pollution.

Avoid the use of chemical fertilizers, herbicides, fungicides and insecticides. Many of these maintenance products contain toxic chemicals or hydrocarbons that may contaminate site run-off flowing into local ground and surface water and they may also kill off beneficial insects. In organic IPM, chemical pesticides are not necessary unless there is the risk of a severe infestation.

In general, vigorous plants and well chosen species growing in biologically active soils with good drainage and a regular placement of compost mulch rarely attract debilitating pests or diseases. Plant growth or plant health problems are often the result of stress caused by poor soil quality, poor drainage, soil compaction or contamination. Slow-release organic fertilizers are available for the initial establishment of native plants, and for ongoing care for high-traffic or ornamental landscapes. Healthy trees and plant communities attract beneficial insects and birds, which provide natural balance and pest control.

Landscape swales, rain gardens and drains require periodic inspections and cleanout. Permeable pavement systems rely on biannual brush vacuuming with a sweeper.

1.6.6 Composting and Soil Management

Most landscape waste is biodegradable and can be turned back into soil or food. Leaves, branches and green waste as well as rotting fruits can be composted to produce mulch and soil amendments. Organic mulch is typically placed as a 50mm layer over landscape beds and rain gardens at the time of installation and for two years afterwards. The decomposed mulch retains moisture and facilitates water infiltration and air movement through an open soil structure. Organic matter, typically high in microbial activity, assists in the buffering of organic fertilizers and the release of nutrients to the plants. Organic matter is also used in lightweight growing media for green roofs and in structural soils under pavement for urban trees.

Refer to the Society for Organic Urban Land Care’s Organic Land Care Standard, Victoria, B.C., 2005 (See www.organiclandcare.org/standard/introduction.php,.)

City Farmer is a great resource for food production, composting, beneficial insects and water-wise gardening: “44% of Vancouver households grow food An urban farm can be a pot of herbs grown on a balcony or a large market garden.” Michael Levenston, executive director of City Farmer. See www.cityfarmer.org/www.richmond.ca/services/recycling/composting/compost.htm. The North Shore Recycling Program has produced Mulch Materials: Just the Facts, a guide to preparing mulch from local salvaged materials (See www.nsrp.bc.ca).

Water stair, Vancouver.

INNOVATIONS 35

2. INNOVATIONS IN DESIGNLEED® credit points focus primarily on energy and environmental design for individual buildings and sites. While the following topics may not be specifically covered under identified LEED® sections, they may be applicable towards achieving Innovation in Design credits. They take steps, beyond what LEED® can cover in a point-based credit system, to create a more socially, environmentally and economically sustainable community.

2.1 Visible Infrastructure

“An architectural method that exploits the unignorable marriage between nature and technology provides an opportunity for new spatial and visual possibilities that result from using infrastructure as a fundamental component of architectural design. Nature and infrastructure must both be allowed to express themselves as a major determinant of urban and regional form. It is up to architects, landscape architects, engineers and biologists to show the way.” Gary L. Strang, “Infrastructure as Landscape,” Landscape Architecture,

pg. 15, vol. 10, no. 3, 1996

There is a tremendous opportunity within the design industry to make sustainable development visible and push the envelope in relating ecological design to development and construction. ‘Green buildings’ can become more than just ‘green’ and more than just ‘buildings.’ They can become dynamic components of our urban landscapes and infrastructure with vertical gardens, visible drainage infrastructure, urban agriculture, canopy walks, roof gardens, living machines, small scale wind turbines and solar arrays. The possibilities are truly limitless.

A visible, sustainable landscape not only performs essential ecological functions in addition to serving the needs of our society, but also creates an urban ecological narrative. For example, City Farmer in Vancouver displays interpretation panels and green technology including a rain barrel, green roof, composter and urban agriculture. Instead of natural processes, human infrastructure and services being hidden away, buried, separated and relegated to back alleys and utility corridors, they are revealed to display the interdependent and vital relationship between the natural world and our role within it. The intersections between nature and human landscapes should reveal the roles our society and our landscapes have in a healthy, sustainable world.

Innovative ecological development has the same potential to revolutionize the way we live, work, learn, play and think as personal computers did a mere 22 years ago.

Streets are daylighted and stormwater facilities are visible at Portrait Homes’ Silver ridge development.

Landscape interprative sign at Citadel Landing a Genstar and Liberty Homes development, Port Coquitlam.

The visible sustainable landscape can tell stories of human systems at work with natural systems, not against them. Environmental features, the history of the site and the culture of the people in the community can present opportunities to capitalize on instead of barriers to be overcome or avoided. Everything—from the interpretive signs identifying plants, to public artwork, to the orientation and massing of a new development—can inherently make connections to the same natural and human processes of landscape and infrastructure.

36 INNOVATIONS

An art installation makes natural processes visible at Kitsilano swimming pool, Vancouver.

“Woodward’s District urban living at the centre of a cutting edge, creative community” (See www.woodwardsdistrict.com).

W

INNOVATIONS 37

2.2 Urban Amenities

The urban landscape can be more than a visible, attractive backdrop to a building, stormwater facility or a shaded parking lot. The use and function of urban landscapes and infrastructures has to relate to and include layers of human use that make them enjoyable spaces for people to inhabit as well. Components of a successful urban environment with healthy social spaces may include:• big shade trees in a continuous canopy —a framework for healthy urban spaces also provides shelter and a food source for wildlife and moderation of microclimates • a diverse variety of spaces—from small to large, private to public, quiet to loud—that allows for as many users as possible to engage their environment in as many ways as possible• opportunities for recreation and play—these are paramount to the health

of the community, promoting interaction with the environment and with neighbours

• public art integrated with the site that tells the story of the environment, history, culture and emerging technology • opportunities for education and discovery—these are essential for people

to learn how things workand to share experiences.

The redevelopment of the Woodward’s site in Vancouver is providing market and non-market housing for a wide range of income levels. Rennie Marketing Systems sold the 536 units of the ‘W’ Woodward’s District in less than two weeks. “Be bold or move to suburbia.” In the concept of workplace housing, people are offered the choice to live close to where they work.

”Lost public space is being regained and new urban spaces established all over the world due to the desire for a better balance between the functions of the city as marketplace, meeting place and traffi c space.” New City Spaces, 2001, by Jan Gehl & Lars Gemzoe, the Danish Architectural Press, Copenhagen.

Cypress Community Gardens, Vancouver.

38 INNOVATIONS

2.3 Urban Agriculture

Fruits, vegetables, herbs and organic produce can be grown locally in community gardens, in the garden, on the roof or climbing up the wall. The requirements are simple: • provide good drainage • supply water to irrigate garden areas and fruit trees—using water stored

in a cistern or rain barrel rather than potable water, if possible • install growing media containing decomposed soil amendments high in

organic matter • provide a compost facility for fruits, vegetables and green clippings to

literally turn waste back into food.

The Vancouver Food Policy Council supports the development of sustainable food systems for the City of Vancouver and fosters sustainable equitable food production, distribution and consumption. In high-density urban neighbourhoods, rooftop gardens with lots of sunshine during the growing season and good air circulation are ideal for vegetable gardens and small fruits. To protect the waterproof membrane, make sure that a root barrier, a thick protection layer and/or green roof modules are used. Consider small mammals, birds and insects such as honey bees in the design of building envelopes and rooftop gardens.

Refer to www.vancouver.ca/commsvcs/socialplanning/initiatives/foodpolicy/key.htm.

“Optimizing synergies between different uses on site requires treating ‘waste as food’. In a closed loop system, … the by-products (‘waste’) of one use provide nutrients (‘food’) for other uses. This approach has been referred to as cradle-to-cradle design because it assigns productive use value to products and their by-products.” Waste As Food, Synergies between uses, by Dockside Green (See www.docksidegreen.com).

Refer to: Cradle to Cradle, Remaking the Way We Make Things, by William McDounough & Michael Braungart, 2001.

The Fressia, a high density residential development in Vancover, markets garden plots on the lower rooftop. “Have the luxury of growing your own vegetation: ripe tomatoes, fragrant basil, fresh strawberries—or freesia, perhaps?” For an additional $2,800 on top of the selling price, a buyer can purchase one of the 1.5-metre-square gardening plots and a small tool locker. See www.freesialiving.com.

The Solar Aquatics Reclamation System, Errington (see www.ecotek.ca).

Living machine, John Todd EcoDesignINFRA STRUCTURES, Malcolm Wells(see www.toddecological.com).

INNOVATIONS 39

2.4 Wastewater Technologies

Innovative wastewater technologies reduce the use of potable water and the off-site treatment of wastewater. Rationales for such technologies include the following:• Containment systems can be engineered to clean wastewater through mechanical and biological filters so that the water bypasses traditional sewer lines. • Reducing the load on sanitary sewers will decrease the frequency of the

overflowing of untreated sewage and stormwater from the combined City of Vancouver sewers into English Bay and the Fraser River during heavy rain events.

• Water reductions and treatment alternatives can eliminate large infrastructure costs, sewer connections and site disturbance. • Low-flow water fixtures reduce potable water consumption.

2.4.1 Living Machines

Living machines or solar-aquatic facilities use sunlight, bacteria, green plants and animals to restore wastewater to pure conditions. An aquatic based reclamation system can be contained within a greenhouse, outside on a site or in a pond or body of water complete with a working ecosystem of microbes, vegetation, invertebrates and fish. Treated water with nutrients can then be supplied to a green roof, living walls and the landscape. Waste is turned into food for plants.

Refer to “case studies” at www.toddecological.com

Sewage is rich in nutrients that can be biologically filtered, recycled and salvaged. The greenhouse and similar indoor and outdoor technologies duplicate, under controlled conditions, the water purification methods of a freshwater wetland ecosystem. Various wetland and aquatic pond plants, as well as snails, worms and fish, process and filter the effluent. The end products of this odorless system are composted biosolids, greenhouse plants and, ultimately, clean water and fish. The water can meet Canadian drinking water quality standards. The clean ‘effluent’ can be used for irrigation and/or reintroduction into surrounding water systems. The greenhouse is capable of multiple functions including silviculture, whereby tree seedlings neutralize toxic materials and are grown for the forest industry, providing revenue for the facility.

Refer to www.greenbuildingsbc.com/Portals/0/docs/case_studies/Beausolell_Solar.pdf and www.ecotek.ca.

The innovative wastewater system at the CK Choi Building at UBC features a subsurface constructed wetland with aquatic plants and microbial life to filter and clean water naturally. A grey water trench is engineered to filter the ‘composting tea’ from toilets and wastewater from sinks. Rainwater is stored in a 25,000-litre cistern for landscape irrigation. “The three-story, $4.5 million building features five composting toilets, functioning completely off the sewage and power grids. And the five compost bins only need to be emptied every 10 years. Ninety percent of the waste is urine, pumped out and treated in a constructed wetland, and red wriggler worms digest the solid waste.” Chicago Tribune, May 22, 2005

Photos courtesy of Cornelia Oberlander,Landscape Architect

40 INNOVATIONS

2.4.2 Grey Water Treatment

In a grey water treatment system, water used while showering, running the tap and using washing machines is collected and treated onsite. The grey water can be used for irrigation, but it must be filtered to take out detergents, chlorine, bleach and other contaminants. The treated grey water can also be used in toilets, for cleaning and operating equipment inside and outside as irrigation for the landscape and green roof. The site can be designed to infiltrate the treated grey water, thereby recharging the local aquifer and reducing the impact on the water table. Unfiltered grey water will clog conventional spray heads or drip emitters and could corrode PVC irrigation pipes.

GREY WATER FILTERRefer to: • www.toolbase.org • www.jscms.jrn.columbia.edu/cns/2005-04-05/mccandlish-composttoilet • www.greenbuildingsbc.com/new_buildings/case_studies/CK_Choi.pdf • www.casestudies.cascadiagbc.org/overview.cfm?ProjectID=44.

Concord Place bicycle and pedestrian routes are part of a greenway along False Creek.

The Greater Vancouver Transportation Authority provides bike lockers for rental—a great option for regular commuters. Call 604-453-4500 or e-mail bikelockers@translink.bc.ca. See www.translink.bc.ca/Transportation_Services/Bikes/default.asp for the Greater Vancouver Cycling Map & Guide.

INNOVATIONS 41

2.5 Bicycle Facilities

Many environmental issues can be lessened by reducing our dependence on automobiles or by eliminating private-vehicle access to selected locations. Urban automobile-related issues include: • sprawling land development • impermeable surfaces • stormwater run-off • heat island effect • air pollution.

To lure commuters and casual drivers from their cars and onto bicycles or feet: • provide convenient and safe bicycle connections to greenways, bike routes and rapid transit stations • provide bicycle storage and pedestrian facilities • provide safe, clear and efficient pedestrian and bicycle access to building entrances.

Many employers, such as Metro Vancouver and Sharp & Diamond Landscape Architecture, purchase monthly TransLink passes for staff or offer incentives for employees to commute by bicycle to work. Showers in the workplace are also important in encouraging employees to cycle to work. Including bike facilities in your project contributes to LEED® Credit SS 4.2.

2.5.1 Bicycle Storage

Bike theft is a recurrent problem in the Lower Mainland. It is important to provide the following: • outdoor, secure bicycle lockers • fully enclosed bicycle lockers (used successfully at several SkyTrain

stations including the King George Station in Surrey) • safety, security and lighting, especially in transitional neighbourhoods that lack informal surveillance.

Several local manufacturers provide a wide range of stainless steel and powder-coated tubular steel bike racks. Avoid galvanized finishes that can scratch the painted surfaces of bicycles. Locally fabricated freestanding bus shelters can be adapted to provide weather protection for bicycles.

Refer to www.metrovancouver.org/parks/greenways.htm for more information about greenways and their locations, as well as linkages to municipal greenways.

Refer to Better Environmentally Sound Transportation (BEST) www.best.bc.ca.

For more information on bikes, visit the Better Environmentally Sound Transportation (BEST) website at www.best.ca

Visit the Greater Vancouver Transportation Authority website at www.translink.bc.ca/Transportation_Services/Bikes/default.asp.

Refer to the International Dark-Sky Association (IDA) website www.darksky.org, and IDA-approved links at www.darksky.org/fixtures/fsa-mfr-list.html.

Full cutoff fixtures line the waterfront promenade at the Versatile Shipyard site in North Vancouver.

42 INNOVATIONS

2.6 Lighting

Light pollution from buildings, streets and parking lots obscures the stars and moon, which many nocturnal insects and animals use for navigation. Minimal lighting, full cutoff lights and carefully selected luminaires will remove excessive light spillage from buildings and sites and will reduce development impact on nocturnal environments. Several cities across North America, including Calgary and Phoenix, have dark skies policies to improve night sky access and to eliminate light pollution. An evenly distributed lighting system allows a continuous supply of safe illumination without dark spots or glare obstructing the sky.

2.6.1 Lighting Strategies

Visual comfort, improved visibility and a safe, secure environment are primarily achieved by eliminating glare and by providing uniform light at lower levels. Strategies include:• selecting low-reflectance surfaces (avoid broom finish cast concrete)• using photocells and timers• removing all unshielded fixtures (floodlights) and unnecessary landscape lighting on the project site • using down lighting techniques or low-angle spotlights rather than up lighting• using indirect lighting (a high quality lighting source that reflects light evenly and provides realistic colour renditions of surfaces and clothing)• using light emitting diode (LED) fixtures that are highly efficient, have a long service life and are cost effective.

Carefully select outdoor illumination and indoor lighting adjacent to windows and skylights to provide safe public use. Choose cutoff or full cutoff luminaires, the lowest wattage lamp packages and look for the International Dark Sky Fixture Seal of Approval for IDA-Approved™ luminaires. (See the International Dark Sky Association website at www.darksky.org.)

“Light pollution blamed for bird deaths. Migrating birds hover in front of city lights until they drop dead from exhaustion or die when they hit the windows. At the height of fall migration over Thanksgiving weekend members of the Fatal Light Awareness Program recovered more than 3,000 dead birds — a new record [in Toronto].” The Vancouver Sun, November 14, 2005

TYPES OF FIXTURES: A cutoff fi xture means less than 1% of light is emitted above 90 degrees horizontal. A fi xture is designated as a full cutoff only if 0% of light is above 90 degrees horizontal. These standards ensure that light is not beamed into the sky, which contributes to light pollution and wastes energy. Such lighting fi xtures contribute to LEED® Credit SS 8.

Ron Basford Park in False Creek, Vancouver. The overburden excavated from the streets of Granville Island was placed and contoured as a park with a grassy hill and informal amphitheatre. Earthen mounds can control acoustics and reduce noise pollution.

Millennium Line noise attenuation/retaining wall.

Carefully designed exterior lighting systems can reduce infrastructure costs and energy use when compared to conventional solutions. Local and North American manufacturers are beginning to respond to commercial demands for indirect light fixtures that fully meet dark skies requirements, however most such fixtures are still cost prohibitive.

2.7 Acoustics

Acoustics is also an emerging field of design and engineering for the urban landscape. Noise or acoustics as related to buildings are assessed by intensity (pressure/angle), composition of building materials and absorption inside the structure. Buildings, walls and landscape elements can reduce the impact and provide absorption through diffusion, diffraction, spacing and choice of materials. Living walls, vegetated rooftops, mineral substrates and configuration of structures can also assist in acoustic management in cities. Planted walls along freeways, arterials and rail lines have proven to be effective in noise attenuation for over 30 years in Europe and North America.

Suppliers and manufacturers that may offer dark sky compliant fi xtures include: • Pace Illumination (see www.paceillumination.com)

• Mac’s II Agencies LTD (see www.macsii.com)• Light Resource (see www.light_resource.com)

INNOVATIONS 43Refer to www.xerofl or.ca.

“Indirect” by Architectural Area Lighting (see www.aal.net).

Refer to LEED® Credit SS 8, Light Pollution Reduction: “Eliminate light trespass from the building and site, improve night sky access, and reduce development impact on nocturnal environments.” LEED® Reference Guide

Green trains: The green track bed course, using green roof technology, is very successful in Europe along rapid transit lines built on grade. Maintenance of the green track is minimal once the green track is established and does not require the spraying of herbicides (a common practice along rail lines in North America). The green track combines environmental strategies by providing a green corridor, heat island reduction and stormwater management. The pre-cultivated vegetation blankets are grown offsite and installed on top of the granular base between the tracks and along the perimeter. The vegetation and integral fabric mat absorb sound at the source between the tracks.

The ‘Eco-Tower,’ from “Scraping The Green Sky” by Lindsay Johnston, Architectural Review 070, TR Hamzah & Yeang Architects, London, England. The EDITT tower is a 26-storey multi-use highrise building proposed for a site inSingapore with a floor space ratio (FSR) of 4.3:1. In the proposal, “a fascinating system of water collection and reticulation is described, involving a sculptural rain scoop on the roof and a system of water collection scallops down the façade combined with a proposal to recycle grey water through soil bed filters in the vertical landscaping.” Wind wing walls are strategically placed on the façade of the tower to create vortices to improve natural ventilation and to reduce wind loads on the building. “The design creates ‘vertical places’, using a ramp system that allows pedestrian movement vertically through the tower along a vertical ‘street’ lined with exhibition and performance spaces, cafes, shops and offices with occasional sitting and gathering areas.”

44 INNOVATIONS

2.8 EcoDensity

The City of Vancouver implemented the EcoDensity Initiative to encourage housing that provides for environmental performance and affordability, and that reflects community interests and needs. The EcoDensity Initiative is endorsed by One Planet Living, a joint initiative of BioRegional (see www.bioregional.com) and the World Wildlife Fund (see www.wwf.org).

This guidebook, Ecological Site Development, discusses a wide range of topics to improve environmental performance. Specific strategies for EcoDensity may include but are not limited to the following:

• Transportation: Locate new development close to rapid transit, bus and bicycle routes and/or close to the workplace, to reduce dependence on private vehicles.

• Transport Emissions: Relax parking requirements to a minimum. This will lower construction costs and reduce not only the volume of excavated material trucked to fill sites in the Fraser Valley but also the resulting fuel consumption, emissions, dust, noise and air pollution.

“The Eco-Density Initiative is also a major step towards achieving One Planet Living in Vancouver, creating opportunities for progress in the following key areas: • Zero Carbon: Greater energy efficiencies, resulting in lowered carbon emissions • Zero Waste: More innovative waste management strategies are possible in dense neighbourhoods • Sustainable Transportation: Better public transit programs and reduced automobile use • Local and Sustainable Materials: More efficient use of building materials and resources • Sustainable Water: More efficient use of water resources than conventional suburban developments

• Local and Sustainable Food: Allows for prime agricultural production closer to urban consumers

• Natural Habitats and Wildlife: Concentrates human settlement, preserving nearby wildlife habitats • Culture and Heritage: Creates vibrant neighbourhoods in which arts, culture, and heritage thrive • Equity and Fair Trade: Greatly enhances opportunities for local economic development • Health and Happiness: Walkable, greener, job-rich neighbourhoods offer higher quality of life”One Planet Living website (see www.oneplanetliving.org/northamerica/EcoDensity.pdf)

INNOVATIONS 45

• Energy Efficiency: Orient the built form and massing to the sun and maximize day-lighting and natural ventilation. Select building envelope systems that lower resource consumption and emissions and improve building performance. Reduce the extent of glazing and curtain walls and provide more thermal mass and vegetated surfaces. Increase the use of renewable energy sources such as solar power and wind power (using micro turbines).

• Microclimate Management: Incorporate vegetated building envelope systems including green roofs, rooftop gardens for urban agriculture, living walls and structures to support climbing plants to insulate and shade the building. Large urban trees also provide evaporative cooling of ambient temperatures, shade surfaces and intercept stormwater.

• Water Resources: Collect rainwater to minimize stormwater run-off, to lower the use of treated drinking water and reduce off-site infrastructure cost. Green roofs, rain gardens, trees, permeable surfaces, cisterns and underground tanks provide biofiltration and/or storage. The water is then available for toilets, washing machines, industrial uses and landscape irrigation. Grey water treatment through solar aquatics, living machines and soil filter beds reduces the cost of sanitary connections and off-site treatment.

• Green Streets: Green corridors and open spaces replicate natural processes such as cooling the microclimate, mitigating stormwater run-off and improving air flow. Streets and open spaces support large trees with umbrella canopies, biofiltration swales, permeable surfaces and biodiversity/wildlife habitat.

• Dark Skies: Light pollution, light trespass (to neighbouring properties) and risk to nocturnal animals (such as birds) are controlled by selecting full cutoff light sources and directing light sources away from windows and reflective surfaces.

• Acoustics and Health: The built form, orientation and building surfaces as well as surrounding open space can contribute to a quieter and healthier city. Interconnected ecological design strategies contribute to livability and affordability, both in lower capital cost and in long-term energy and operational cost savings.

The coastal bluff ecosystem is a source of native plants for windswept roofs.

Extensive green roof/eco-roof on the RCMP Justice Building, Sechelt.

CASE STUDY #1 47GREEN ROOF

3. SUSTAINABLE TECHNOLOGY SERIES

Case Study #1Extensive Green Roof

Technology in Brief

Green roofs are engineered vegetated roofing systems that absorb rainwater and carbon dioxide while releasing water and oxygen back to the atmosphere through evapotranspiration and photosynthesis, just as any vegetated landscape would. Green roofs offer multiple environmental benefits including reducing the heat island effect, conserving energy by decreasing ambient temperatures, offsetting CO2 emissions, attenuating noise, providing wildlife habitat and acting as an urban amenity. As well, living roofs significantly extend (double) the life of the waterproof membrane by protecting the roof from UV degradation.

There are two main types of green roof systems:

• An extensive green roof system features lightweight growing media, usually between 50 to 150mm (2” to 6”) in depth, installed over drainage and/or moisture retention layers on top of a root barrier and waterproof membrane.

• An Intensive green roof is typically 200mm (8” to 4’) in depth, usually requiring regular irrigation and landscape maintenance to support trees, shrubs, lawns, planting beds, vegetable gardens and/or a greater diversity of wildlife habitat.

A third type of green roof, the eco-roof, is a type of extensive green roof system that forms a self-sustaining ecosystem featuring native and hardy sedums, grasses and/or wildflowers when established and requires little or no maintenance. The planting composition for eco-roofs replicates the coastal bluff ecosystem characterized by thin soils on windswept sites, subject to extremes in temperature and moisture stress. Pre-cultivated vegetation blankets or pre-grown modules are also available as are systems for sloping roofs of up to 30 degrees.

ADDITIONAL REFERENCE: Greening Gotham, a project of the Earth Pledge Green Roofs Initiative (see www.greeninggotham.org/greenRoofs.php).

48 CASE STUDY #1 GREEN ROOF

Structurally, lightweight green roof systems (50 to 150mm in depth) have a saturated weight of 50 to 170 kg/m2 (10 to 35 lbs. per square foot). Green roofs systems can be installed on new or existing wood frame, steel and track beds. Extensive green roofs are generally inaccessible to public use as many drought tolerant species do not handle foot traffic. Eco-roofs, however, can be designed to accommodate walkways and railings, and can be combined with intensive rooftop gardens and urban agriculture.

In 2006, the cost of installing an extensive eco-roof (not including the membrane) was relatively low at $80 to $200 per square meter, depending on the membrane system, access to the roof and size of the project. The costs are decreasing with increasing use of local materials and equipment such as express blowers and tote bags that reduce installation time. Green roofs in Europe cost as little as CAN $50 to 60 per square meter installed. This green roof technology is endorsed by the Roofing Contractors Association of B.C. (RCABC) and offers a conventional five-year warranty. In some cases, municipal governments in North America offer incentives, grants and stormwater credits to developers who install green roofs.

Potential LEED® Credits

Green roofs may contribute to earning multiple LEED® credits when used in combination with other sustainable building elements.

Green roofs contribute towards Indoor Environmental Quality (EQ) credits including for daylight and views, air filtration and oxygen loading (locate operable windows and air intakes at the green roof). Additional LEED® credits to consider include:• SS 5.1, Reduced Site Disturbance, (if a vegetated roof covers at least

half of the degraded site area)• SS 6.1, Stormwater Management, Rate and Quantity• SS 7.2, Landscape Design to Reduce Heat Islands, Roof• WE 1, Water Efficient Landscaping (2 credits)• EA 1, Optimize Energy Performance and Energy Efficiency (multiple

credits)• MR 5, Local / Regional Materials (2 credits).

ADDITIONAL REFERENCE: Refer to Green Roofs and the LEED® Rating System, by Richard Kula, Prairie Architects Inc. 2004 (also see www.greenroofs.org)

Installation of lightweight growing medium on the Sechelt RCMP green roof, District of Sechelt.

Sechelt RCMP green roof after three months of drought (irrigation not required).

Thinking ‘outside the box’ and designing eco-effective solutions can earn LEED® Innovation in Design credits. (Refer also to Part 2, Innovations in Design, in this Guidebook, particularly Sections 2.1 - 2.4). Additional topics might include:• ID 1.1, Innovation in Design, Education and Interpretation• ID 1.2, Innovation in Design, Wildlife Habitat for Endangered Species,

(specific plants and animals can be protected on the roof)• ID 1.3, Innovation in Design, Composting and Soil Management• ID 1.4, Innovation in Design, Food Production, Urban Agriculture.

Evaluation for Application

The selection of a green roof system typically involves an architect, structural engineer, landscape architect and roofing specialist, as well as a qualified contractor and maintenance manager.

Early in the design process, the client and consulting team establish the development program and explore building massing and siting to optimize energy and environmental performance objectives. Green building systems that provide multiple ecological benefits at a lower lifecycle cost, such as green roofs, are explored.

Preliminary green roof plans are presented to the design team for review and co-ordination among disciplines. Development permit drawings for the project, including building, landscape and roof plans, are submitted to the municipality for approval based on zoning bylaws and/or design guidelines. Detailed design drawings and specifications are issued for building permit application (BPA) purposes, showing compliance with fire, safety, access, water supply and other codes. (See the Sample Outline Specification prepared for the Sechelt Justice Building).

The green roof is designed as part of a complete roofing system and forms an integral part of the building envelope. Design considerations include structural weight, edge conditions, vegetation-free zones, mechanical vents, drains, water supply, access to the roof and safety of personnel during construction and maintenance. A lightweight growing medium is selected to provide moisture retention, drainage and nutrients for the plants, as well as long-term stormwater performance, water quality and plant survival. Water supply to the roof is required for irrigation during establishment maintenance, and could be available in case of fire hazard or extreme drought.

Logistics for green roof implementation include the specialty growing of plants on contract with a nursery, blending of the growing medium, delivery of materials up to the roof, storage and coordination of procedures. Training the general, roofing and landscape contractors in installation techniques and safety practices is essential, as is protection of the membrane at all stages

CASE STUDY #1 49GREEN ROOF

Wildlife on the green roof at Sechelt.

of construction and maintenance. Warranties are provided by the Roofing Contractors Association of British Columbia (RCABC) and by the roofing manufacturer for a complete green roof system. The RCABC requires an inspection of the membrane prior to placment of the green roof components.

If the establishment of the green roof precedes the installation of windows and building siding, protect the plants and growing medium from damage (contamination and compaction) by sub-trades. Additionally, watch out for crows that may pull out plant plugs while looking for food (grubs). Complete establishment of the plants during the critical first year of maintenance is necessary for appearance and green roof performance (see Establishment Maintenance, below).

Sample Outline Specification

The following outline specifi cation is for the Sechelt Justice Building.1. Waterproof Membrane and Drainage System a. Membrane: SBS 2-ply modified bitumen torch-on roof b. Root barrier (recommended but not installed) c. Non-reservoir drainage mat with integral non-woven filter fabric d. Vegetation-free zone with recycled wood-polymer curb around the perimeter of the roof and adjacent to drains

2. Irrigation (operated on a temporary basis for plant establishment) a. PVC pipes and fixed overhead spray heads on low risers b. Water supply to the roof by mechanical incl. back flow preventer, winterization tee, and hose bid c. Power supply for a controller (time clock) and low voltage wires to remote valves

3. Lightweight Growing Medium a. 80% black pumice, 3 to 5mm with 2mm minus aggregate b. 20% organic matter (blended soil amendments)

Granulometric distribution range for vegetation substrates at single-course extensive greening sites, Guideline for the Planning, Execution and Upkeep of Green-Roof Sites (see www.fl l.de)

50 CASE STUDY #1 GREEN ROOF

Planting and 12-month establishment maintenance at Sechelt, District of Sechelt.

35mm x 50mm plugs planted 200mm on centre at Sechelt.

CASE STUDY #1 51GREEN ROOF

4. Installation a. Coordinate with general and roofing contractor (membrane) b. Protect roof membrane and clean building surfaces c. Deliver growing medium on the roof with crane. Place in ‘Gerber’ boxes (clean concrete buckets), tote bags or by express blower, installed to a uniform depth of 75mm (3”)

5. Supply of Plant Material a. Select drought-resistant species: cuttings and seeds of native sedums and hardy grasses collected for propagation b. Contract the growing of the plants by a specialist nursery: propagate,

72 plugs per tray c. Allow 3 to 6 months to grow plugs and for proper root development. Ensure plugs are not root bound d. Plant immediately upon arrival at the site

6. Planting Procedures a. Install plants in the late summer (September), early fall or early spring. Avoid freezing or extremely hot conditions b. Plant spacing: 200mm on centre, avoiding the use of metal tools For plugs, use a tough nylon transplanter/trowel used for bulbs c. Water and fertilize (13-26-6 or equivalent) immediately to promote root growth (see Establishment Maintenance, below).

Establishment Maintenance

Establishment maintenance is essential for green roof performance, vigorous plant coverage, dense root growth and improved water and energy efficiency. Key requirements during the establishment maintenance period (12 to 18 months) include watering, fertilizing, weeding (careful removal by hand) and monitoring. Monitoring includes checking drains twice a year and removing debris.

Operate an automatic irrigation system during dry periods in the first full growing season. As an option, water by hoses and/or spray heads on

CREDITS:Sechelt Justice Building and RCMP, Sechelt, B.C. Green Roof Completed: September 2002Client: District of Sechelt, B.C. Buildings CorporationArchitect: Johnston Davidson Architecture + PlanningLandscape Architect: Sharp & Diamond Landscape ArchitectureMechanical Engineer: Keen Engineering (now Stantec)Roofi ng Contractor: Marine Roofi ngLandscape Contractor: Deluxe LandscpaingNusery Supplier Peels Nursery (see www.peelsnurseries.com)

52 CASE STUDY #1 GREEN ROOF

platforms, but remember that plants can be easily trampled. For the purpose of LEED® certification, the owner agrees to operate the system on a temporary basis only (for 12 to 24 months).

Fertilize with light applications of a slow release organic fertilizer, first to stimulate root growth, and follow with three applications of a more complete fertilizer, every 45 to 60 days during the first growing season.

Water and fertilizer encourages weed growth that restricts plant growth and health. Windblown seeds from surrounding sites can be a nuisance. Schedule weekly inspections and weeding during the first growing season to remove invasive plants (such as clover) before they spread and go to seed. Once established, tough hardy sedums and grasses will out compete most invasive plants. Once established, a green roof can expect to achieve 95% plant coverage in 12 to 18 months.

Resources

Planting Green Roofs and Living Walls, Nigel Dunnett and Noel Kingsbury, Timber Press, Portland, OR, c. 2004, ISBN 0-88192-640-X

Green Roofs, Ecological Design and Construction, Earth Pledge, Schiffer Publishing Ltd, Atglen, PA, c. 2005, ISBN 0-7643-2189-7

Guidelines for the Planning, Execution and Upkeep of Green Roof Sites, by Forschungsgesellschaft Landschaftsentwicdklung Landschaftssbau (FLL), c. 2002, (see www.f-l-l.de/english.html)

E2396-05 Standard Test Method for Saturated Water Permeability of Granular Drainage Media [Falling-Head Method] for Green Roof Systems, ASTM

E2397-05 Standard Practice for Determination of Dead Loads and Live Loads associated with Green Roof Systems, ASTM

E2398-05 Standard Test Method for Water Capture and Media Retention of Geocomposite Drain Layers for Green Roof Systems, ASTM

E2399-05 Standard Test Method for Maximum Media Density for Dead Load Analysis of Green Roof Systems, ASTM

Green roof websites:

• www.greenroofs.org — Green Roofs for Healthy Cities, North America

• www.greenroof.se — International Green Roof Institute

CASE STUDY #1 53GREEN ROOF

• www.greenroofs.com — A green roof directory of roofing manufacturers, suppliers of green roof products and resources

• www.greenroof.bcit.ca — BCIT Green Roof Research Facility and CAGRT

• www.gnla.ca/library — Green Roof Policy: Tools for Encouraging Sustainable Design, by Goya Ngan, 2004, Landscape Architecture Canada Foundation

• www.toronto.ca/greenroofs/findings.htm — The City of Toronto’s new Green Roofs website and their new report on the city-wide benefits of green roofs in Toronto, for stormwater, energy consumption, urban heat island effect, air quality and emissions

• www.greenroofs.org — Green Roofs for Healthy Cities, an organization

working to develop the North American green roof market and hosting the annual Green Roofs for Sustainable Communities conference.

Photo courtesy of Cement Association of Canada

www.cement.ca

CASE STUDY #2 55PERVIOUS CONCRETE

3. SUSTAINABLE TECHNOLOGY SERIES

Case Study #2Pervious Concrete

New pavement construction technologies provide multiple ecological, social and economic benefits including clean water, long-lived trees, cool environments, quiet streets, healthy cities and reduced infrastructure costs. Pervious concrete applications are used successfully for parking lots, pavements around urban trees, tennis courts, industrial purposes, hydraulic structures, greenhouses, thermal insulation for buildings and sound barrier walls for acoustic control. Pervious or porous concrete is made with the same components as dense concrete: Portland cement, water and aggregate. (See also Section 1.3.2, Porous Pavement, in Part 1 of this guidebook.)

Technology in Brief

Pervious or porous concrete is a structural concrete pavement that provides water infiltration, reduces run-off, and recharges aquifers. Pervious concrete, when correctly installed, has a void space of 15 to 20% that allows infiltration of stormwater at a rate of 200L/m2/minute (0.34cm/second) or higher. The void spaces in the concrete provide an environment for naturally occurring microorganisms that digest oil drippings from parked cars. In comparison with conventional pavements, porous concrete can provide the same structural pavement function while reducing or eliminating the need for a separate stormwater system and off-site treatment.

A successful example of the porous paving technology is the main parking lot for the Clean Water Services Field Operations Facility in Beaverton, Oregon. The pavement structure for the 1700m2 parking area has a 450mm (18-inch) base course and subbase to allow adequate storage capacity for a 25 year storm event. Storing the water in the base course permits water to drain quickly, thereby protecting it from freeze/thaw cycles. Below the subbase, geotextile fabric is installed to stop fines from migrating up into the base. To prevent water from rising to the surface, a 6-inch perforated pipe with filter fabric, running the length of the parking lot, is placed within the subbase.

In combination with structural soils, porous pavements give urban trees the rooting space they need to grow to full size. Structural soil combines no-fines aggregate with organic matter and soil amendments. The porous surface allows air and water to flow into the rooting zone. During the summer, the surface temperature of a porous parking lot is much cooler than conventional asphalt surfacing. Porous concrete’s light colour and porosity may help combat the urban heat island effect, however; further research is required.

Clean Water Services Field Operations Facility, Beaverton, Oregon.

Photo courtesy of Portland Cement Assoc.

56 CASE STUDY #2 PERVIOUS CONCRETE

Potential LEED® Credits

Pervious Concrete can contribute to earning multiple LEED® credits such as:• SS 6.1, Stormwater Management, Rate and Quantity• SS 7.1, Landscape Design to Reduce Heat Islands, Non-Roof (rooting

space for large canopy trees, light colour and porosity)• MR 5.1, Local/Regional Materials• MR 5.2, Local/Regional Materials.

Evaluation for Application

During an integrated design process, the client and consulting team explore a range of solutions to transportation issues, stormwater run-off, heat island effect and restoring natural systems. The selection of a pavement system typically involves the expertise of a civil, geotechnical and/or mechanical engineer as well as an architect, landscape architect and possibly a hydrologist to assess ground water conditions.

A life cycle assessment of pervious concrete shows a longer life compared to asphalt paving, lower energy costs (for cooling) and significantly reduced stormwater infrastructure maintenance. Porous pavements can eliminate the need and cost for catch basins and pipe conveyance systems.

The complete installation cost for the 300mm-thick pervious concrete parking lot in Oregon was $400/m2 (in 2003 Canadian dollars). The 300mm-thick parking pavement was over designed by a factor of two. Reducing the thickness to 150mm would lower the cost to approximately $150/m2 (in 2005 Canadian dollars). “The higher installation costs are offset by no engineering, installation or maintenance of conveyance systems, including pipes, catch basins and detention facilities.” Slow the Flow, Clean Water Services, Oregon, July 2004.

Technology and installation contractors are still relatively inexperienced in the Pacific Northwest. Some variations of the mixture and semi-porous concretes are being considered and tested. Pervious concrete was used for a sidewalk installation in Saanich, B.C. When the plans for the Clean Water Systems’ parking lot began in 2002, there was only one qualified concrete contractor.

“This is a revolutionary new way to integrate healthy ecology and thriving cities: living canopy above, the city’s traffi c on the ground, and living roots below.” Pervious Concrete Pavements, Paul D. Tennis, Michael L. Leming & David J. Akers, c. 2004, Portland Cement Associate, Skokie, IL.

Clean Water Services Field Operations Facility, Beaverton, Oregon

Photo courtesy of Portland Cement Assoc.

CASE STUDY #2 57PERVIOUS CONCRETE

Many contractors exist in Oregon and Washington. The pervious concrete mixtures may be limited to parking lots and streets with low traffic volume and speeds. Both longer-term studies of durability and maintenance and local expertise are required for local acceptance and implementation.

Sample Outline Specification

The following outline specification is for the Clean Water Services Field Operations Facility in Beverton, Oregon.

1. ‘Zero-Slump’ Mixture Design a. Aggregate 1190 to 1480 kg/m3

b. Cementitious materials 270 to 415 kg/m3

c. Water : cement ratio (by mass): 0.27 to 0.34 d. Aggregate : cement ratio (by mass): 4 to 4.5:1 e. Fine : coarse aggregate ratio (by mass): 0 to 1.1 (the addition of fine aggregate will decrease the void content and increase strength) f. Chemical admixtures, particularly retarders and hydration stabilizers, are also commonly used, at dosages recommended by the manufacturer. Use of supplementary cementitious materials, such as recycled fly ash and slag, is common as well

2. Installation a. Place concrete with a conveyor system 12mm (1/2 inch) above final finished grade and cover with plastic to limit the amount of moisture loss b. Compact and flatten with min. 400 pound automated roller to final surface grade c. Important: keep the sub-grade clean and damp when placing concrete d. Cover concrete with plastic for seven days e. Minimize any compaction that would reduce the void structure f. Joints at 10 feet on centre to avoid clogging the concrete.

Maintenance

The maintenance requirements for the parking lot at the Clean Water Services facility in Oregon have been much less intensive than initially expected. During construction, careful attention is needed to protect surfaces from contamination. After construction, periodic vacuum sweeping keeps fine materials from clogging pore spaces.

Refer to: Pervious Concrete Pavements, Paul D. Tennis, Michael L. Leming & David J. Akers, c. 2004, Portland Cement Associate, Skokie, IL.

58 CASE STUDY #2 PERVIOUS CONCRETE

Resources

ASTM C 140, ASTM C 42 and others, various standards and testing procedures for concrete and pervious concrete

Porous Pavements, Bruce K. Ferguson, CRC Press, Athens, GA, 2005, ISBN 0-849326702

Pervious Concrete, American Concrete Institute Committee, 2006.

Pervious Concrete Pavements, Paul D. Tennis, Michael L. Leming &David J. Akers, 2004, Portland Cement Associates, Skokie, IL

The website www.glaciernw.com, for Glacier Northwest, Seattle Washington

The website www.nrmca.org, for the National Ready Mixed Concrete Association, (search ‘pervious concrete’)

Slow the Flow, Clean Water Services, July 2004

CREDITS:Clean Water Services Field Operations Facility, Beaverton, OregonCompleted: August 2003Client: Clean Water ServicesArchitect: WBGS Architecture and PlanningCivil Engineer: URS/BRWMechanical Engineer: Interface EngineeringLandscape Architect: Murase AssociatesConcrete Contractor: Merlino ConstructionReady Mix Concrete Supplier Glacier Northwest (see www.glacierhw.com)