Low Impact Development

Maria Ignatieva

West Coast of the USA

• Oceanic climate • Quite high rainfall

averages (920 mm) per year (Portland, Oregon)

Low Impact Development

in Puget Sound

Washington & Portland

Oregon, USA

Paradigm Shift

• View water as a resource instead of a nuisance to contend with during development

– Replenish aquifers– Store & use rainwater – Remove some contaminants on site and

deliver cleaner water downstream

Overview

• Stormwater has harmed, and continues to harm, Puget Sound’s resources (for example, several species of Northwest salmon face the threat of extinction,numerous shellfish-growing beaches are too polluted to harvest)

• Traditional land development and stormwater practices have not proven effective at preventing harm (pollution threatens the health of urban water and underwater sediments; runoff from stormwater contributes significantly to these problems)

• Low impact development is a key piece in overall approach to managing stormwater

Effects of Stormwater on Water Quantity

• Flooding and property damage.

• Damage to stream channels during wet months

• Lower stream flows during dry months, less groundwater recharge.

Photo courtesy Hans Hunger, Pierce County Water Programs

Effects of Stormwater on Water Quality

• Restrictions on shellfish harvest

• Harm to fish and other aquatic life.

• Polluted sediments

Photo courtesy Taylor Shellfish Farms, Inc.

Many Puget Sound species are harmed by stormwater runoff

Photo courtesy Al Latham, Jefferson Conservation District

Watershed Hydrology BEFORE Development

evapotranspiration: 40-50%

interflow: 20-30%

surface runoff: <1%

Watershed Hydrology AFTER Development

evapotranspiration: ~25%

interflow: 0-30%

surface runoff: ~30%

Traditional Approach toLand Development and Stormwater

Management

• Most trees and other vegetation are removed and native soils are compacted.

• Management techniques are applied at the end of site design.

• Relies on pipes, stormwater ponds and vaults.

• Stormwater is managed far from source, after collection and conveyance.

Limitations of Traditional Approaches

• Not all impacts can be mitigated.

• Infrastructure is expensive.

• Maintenance is expensive, often neglected.

• Uses a lot of land, often not attractive.

• Treats rainwater as a waste, not a resource.

Photo by Stuart Glasoe, Puget Sound Action Team

Low Impact Development

• Uses suite of site design elements and practices.

• Mimics site natural hydrology.

• Protects and uses site’s natural features.

• Uses many small-scale stormwater controls.

• Manages stormwater close to the source.

• Applies to urban, suburban & rural sites.

Key Elements of LID

• Assess the site thoroughly.

• Integrate stormwater management into site design from beginning.

• Design site to cluster development and conserve vegetation, soils, and natural drainage features.

• Reduce and disconnect impervious surfaces.

• Use small-scale practices to disperse and infiltrate.

• Maintain practices and educate landowners.

Benefits of LID

• Can better protect water resources.

• Can reduce infrastructure costs.

• Creates more attractive, livable communities.

• Can enhance property values.

• Helps meet stormwater requirements.

Integrated Management Practices

• Preserving-clustering-dispersing

• Bioretention

• Amended soils

• Permeable pavement

• Vegetated roofs

• Rainwater harvesting

• Minimal excavation foundations

High Point, Seattle

Integrated Management Practices

• Preserving-clustering-dispersing

• Bioretention

• Amended soils

• Permeable pavement

• Vegetated roofs

• Rainwater harvesting

• Minimal excavation foundations Photo courtesy Seattle Public Utilities

Integrated Management Practices: Bioretention

• Bioretention (rain gardens and swales):

shallow, landscaped areas composed of soil and variety of plants

rain gardens: stand alone feature-small depressions near homes and other buildings that collect runoff from a roof, driveway or yard and allow it to infiltrate into the ground.

swales: part of a conveyance system

High Point, Seattle: Swale

Bioswales are shallow depressions created as opened storm water conveyance systems that are generally not as elaborately landscaped as bioretention systems and are primarly designed for transportation and infiltration of storm water

Rain Gardens: Portland, Oregon USA

• Bioretention

• Amended soils

• Permeable pavement

• Vegetated roofs

• Rainwater harvesting

• Minimal excavation foundations Photo courtesy Seattle Public Utilities

Integrated Management Practices

• Bioretention

• Amended soils

• Permeable pavement

• Vegetated roofs

• Rainwater harvesting

• Minimal excavation foundations Photo courtesy 2020 Engineering

Integrated Management Practices

Integrated Management Practices: Permeable pavement

• Permeable pavement: allows water infiltrates and removes pollutants. Includes concrete, asphalt, pavers and grid system filled with grass or gravel.

High Point, Seattle

• Bioretention

• Amended soils

• Permeable pavement

• Vegetated roofs

• Rainwater harvesting

• Minimal excavation foundations Photo courtesy SvR Design

Integrated Management Practices

Vegetated roof in Seattle

• Bioretention

• Amended soils

• Permeable pavement

• Vegetated roofs

• Rainwater harvesting

• Minimal excavation foundations Photo courtesy Northwest Water Source

Integrated Management Practices

• Bioretention

• Amended soils

• Permeable pavement

• Vegetated roofs

• Rainwater harvesting

• Minimal excavation foundations Photo courtesy Tom Holz

Integrated Management Practices

Applying LID Principles & Practices

Graphic courtesy AHBL Civil and Structural Engineers

tree conservation • soil amendmentsnarrower streets • open drainage • rain gardens

on-site detention, storage and infiltration

Photo courtesy LID Center

Applying LID Principles & Practices

Example of using LID practice : High Point Public Housing Redevelopment in

Seattle

• 120 acre• Higher density• Mixed-used• Narrow street• Swales• Big retention pond• Pervious pavement

High Point: Retention Pond

High Point, Seattle

High Point, Seattle: Community Garden

Photo courtesy King County Rooftop rainwater collection, Seattle

Photo courtesy Bill Lewallen, Snohomish County

Grass pave system, Everett

F

New Seasons Market, Portland

F

Stormwater Management……

F

as art! New Seasons Market, Portland

LID examples

• 2000-2003 the Seattle Street Edge Alternatives-SEA Streets project-Seattle Public Utilities Department

• Prevented all dry season runoff and 90% of wet season runoff

• Help protect nearby salmon streams by reducing stormwater volume by 99%

                                                                                                                                                                                                                  

Welcome to the virtual tour of SEA Street, a Seattle Public Utilities Natural Drainage Systems (NDS) project located in northwest Seattle. This prototype project, the first NDS project in Seattle, shows a range of unique drainage and street design innovations. The tour begins at the intersection of 2nd Avenue NW and NW 117th Street, and moves north along 2nd Avenue NW to NW 120th Street. At each stop in the tour, labeled on the map of the project site below, you'll learn about the goals of this pioneering project:

                                                                                                                                                                                                                                                                                                            

                                             

                    

       Drainage

                  

       Water Quality

                  

       Landscape

                  

       Mobility

                  

       Community

                  

       Education

      Next

Photo Courtesy Seattle Public Utilities

SEA Street Before….Photo Courtesy Seattle Public Utilities

SEA Street After

Photo Courtesy Seattle Public Utilities

Photo Courtesy Seattle Public Utilities

SEA Street: 2007

Example of LID practice: rain garden in Portland, Oregon

Sustainable Construction Practices in USA

Leadership in Energy and Environmental Design (LEED)

• US Green Building Council rating system for designing, constructing, operating and certifying green buildings.

LEED BuildingsLeadership in Energy and Environmental

Design:

• 11 buildings in Seattle: City Hall and Central Library

US Green Building: Chicago Center for Green Technology

1999 Chicago Department of Environment

• Clean-up process of the site

• Feature: Increasing Energy Efficiency:

1. Window, light fluorescent bulbs

2. Smart lights: maximum natural sunlight

3. Heating and Cooling

Feature: Reducing vehicle emissions

Feature: Electric outlets for cars

Feature: Public transportation

Feature: Bike parking

Feature: Local materials

Chicago Center for Green Technology Outside: Rain Cisterns- use for watering plants

Chicago Center for Green Technology Outside: Solar Energy: Solar Panels

Low Impact Urban Design and Development in New Zealand

New Zealand Low Impact Urban Design and Development Programme

LIUDD

FRST subcontract: Landcare Research

New Zealand Limited, a New Zealand

Crown Research Institute

2003-2009

New Zealand Urbanization

87 % of New Zealand population live in an urban environment

Biggest Cities: Auckland,

Wellington,

ChristchurchThe fastest growing urban areas by 2021:Auckland (population growth of 36%) and Selwyn District (south of Christchurch, 42%).

Urban ecology in New Zealand:Biodiversity of the urban environment

• Major concern: loss of indigenous biodiversity

• Problems with naturalized exotic species (plants, birds and animals)

• New Zealand vascular flora:• 2500 indigenous (native)

vascular species, • 2500 completely naturalized

alien plants • Over 20,000 exotic vascular

plant species • 10% of which have escaped

into the wild• 13 more becoming naturalised

every year• Native flora gets pushed back

into inaccessible areas• Similar for wildlife

Urban biodiversity and design:New Zealand Low Impact Urban Design and

Development (LIUDD)• Apply different

sustainable devices (similar to the USA): swales, rain gardens, green roofs, impervious surfaces. Compact development principles.

• The key goal is to protect and enhance native urban biodiversity

• (LIUDD) associated with specifically employing native plants and attracting native species of wildlife

“Low Impact Urban Design and Development: Making it Mainstream”

• Interdisciplinary approach: social researchers, environmental scientists, planners, engineers, landscape architects and ecologists

LIUDD

• Planning & design for physical sustainability and biodiversity

• Relevance (sense of place) and effectiveness will depend on visibility to the bulk of the population – in the urban environment

LUIDD: Stormwater best sustainable

management practices at catchment scale • Follows the treatment train principle – slowing and

lengthening the passage of water moving through the urban catchment from roof to sea or groundwater.

• Main roads and secondary roads provide for biofiltration using vegetated swale systems. Swale design details from “Stormwater treatment devices from Low Impact Design” manual for Auckland Area

• Permeable pavement (less paving areas, shared driveways)• Detention Pond• Rain gardens, rain cisterns, green roofs for an individual

property (optional)• Permeable ecological surfaces (driveways) for individual

properties (optional)• Ecological protection, restoration, design at local to

landscape scale

LIUDD

• Involve principles of landscape and urban ecology

• Alternative, cost-effective design and development approaches that involve designing and working with nature - creating community environments that respect, conserve, and enhance by or with natural processes

• Creating systems of ‘stepping stones’ and green corridor systems, that can lead native birds back into cities.

• Reintroduction of native biodiversity in urban environment

LIUDD: Overall planning principles of subdivision

• Spatial resource survey to identify significant values that must be protected

• Respect existing topography, landforms and native vegetation as part of the legible landscape

• Open green spaces (including native patches); emphasis on the organisation of common open spaces with native reserves and pedestrian linkages rather than cul de sacs.

Concept plan for Regis Park Subdivision. DJ Scott, Auckland, New Zealand, 2003

2005: Aidanfield (Christchurch) Analysis and developing scenario for LIUDD

Design: Frazer Baggeley, 2005

Ecological Design in Lincoln Village

Propose a System of Green Corridors for Lincoln Village and surrounding landscapes

Possible connections between Lincoln Village and surrounding ecosystems such as Lincoln University, Landcare Research campus, Liffey River and even Port Hills.

Design: James Rea, 2006

Clustaring Houses: saving energy and space for habitat

• Localised high density; mixed-use subdivisions can allow larger areas of public open or green space

• These creates more opportunities for core sanctuary habitat, rather than small fragmented or linear features with inadequate buffer zone

Vegetated Swale

J.Collett (2007). Proposal for Liffey Spring Subdivision

LUIDD principles

• Provide for pedestrian/bike recreational loops (public walkways) and links from all subdivision roads. Narrow walkable street layout with more space for pedestrians and planting (swale planting, street trees, green space)

Cross section of walkable narrow street for new Liffey Spring subdivision in Lincoln Village, New Zealand. Design: Simon Multrie, 2007

Narrow Roads and Streets

Narrow Road. Lincoln, Christchurch. Photo: Robyn Simcock

Narrow Road, Talbot Park subdivision, Auckland. Raingarden on right treating road runoff and forming a traffic-calming feature

LUIDD principles: Formation of storwater treatment trains

• Series of elements or devices linked together from the top to bottom of the urban catchment (roof to gardens, swales and streets to ponds, groundwater and rivers to the ocean) that lengthen and slow the passage of water

Green Roofs

A green roof is a roof partially or fully covered by plants.

Rain tanks for an individual property

• These and rain barrels reduce runoff to waterways and provide water for irrigation without tapping into finite aquifers or potable supplies.

• New plantings may need irrigation for the first few summers. Rainwater tanks and the retention of vegetation on upper catchment large lots are a mandatory requirement in various northern districts of NZ

North Shore City. Photo: Penny Lysar

Permeable ecological surfaces (driveways) for individual properties

• One of the most effective means of ameliorating rapid stormwater runoff is to minimise hard surfaces and to use permeable materials when needed for hard wearing or vehicle standing.

Example of permeable paving with grass, Morning Star Apartments, Auckland, New Zealand.

Courtyard with four different permeable surfaces: wooden decking, gravel, permeable

pebble pavers (around tree) and grass, at Waitakere Civic Centre, Auckland

LIUDD: Swales and filter strips

Mown grass swale, (drainage gate at front pipes into inflitration bed)

LIUDD: Swales and filter strips

• Unmown Carex cv and (Lower) - prostrate Coprosma bioretention/infiltration strips at Wharewaka Taupo (at least 1 m depth of non-consolidated material). Note stone detention dams used to reduce flow strength.

Photo: Robyn Simcock

Swales

Vegetated swale; Ryelands Subdivision, Lincoln, New Zealand

Swales

Permanently wet swale with native Juncus species. Car park in Waitakere, Auckland, New Zealand. Design: Meghan Wraight.

Aidanfield (Christchurch): Swale Proposal

Design: Frazer Baggeley, 2005

Detention Pond

Vegetated swale and overflow detention pond, Aidanfield, Christchurch, Photo: Colin Meurk

Enhancing biodiversity in the home garden and public space

• We have dealt with the hydrological and ecological service function of plants and suggested a number of indigenous species that can be used for these roles.

• Under this heading we consider the specific intrinsic values of biodiversity, why we should promote it and how we can integrate it into the urban context.

• In particular we focus here on the urban matrix of private gardens and public parks and other spaces.

Enhancing biodiversity in the home garden

• Trees• Shrubs• Hedges• Rock gardens• Native lawns• Green walls• Herbaceous borders Green wall for private house at Liffey

Spring Sbdivision, Lincoln. Design: Jason Collett, 2007

Green Wall at the Pacific Museum, Paris

Native lawn

Gnaphalium audax in a Christchurch Lawn. Photo: Colin Meurk

Rock Gardens

Rock Garden. The Bush City. Te Papa, Wellington

LUIDD in Urban Public Spaces: Parks. Street trees and avenues

Native plants for traffic islands. Wellington

LUIDD principles in action: Waitangi Park, Wellington

• LIUDD principles: stormwater treatment and using native plants as highly visible and key drivers of the overall design

• Representation of rain gardens, wetlands, and coastal vegetation

• Designer: M.Wreight

Ecological protection, restoration, design at local to landscape scale

Revegetation of pasture blocks during rural residential subdivision at Owhanake, Waiheke Island. Photo: Marjorie van Roon

New Zealand LIUDD practical applications: the manual

• How to Put Nature into Our Neighbourhood: Application of Low Impact Urban Design and Development (LIUDD) Principles, with a Biodiversity Focus, for New Zealand Developers and Homeowners

Demonstration Gardens in Christchurch Botanic Gardens “Design with Indigenous

Plants”

• Showcase ways to appropriately apply native species in particular settings

• Gardens display at a realistic scale of private house situation

• How principles of Low Impact Urban Design and Development can be implemented into an individual residential property to improve sustainability and biodiversity and reduce costs at both a site, and wider regional scale.

Demonstration Gardens in Christchurch Botanic Gardens “Design with Indigenous

Plants”, May 2008

Demonstration Gardens