Low Impact DevelopmentProtecting Oregon’s waters as we grow

IntroductionIntroduction

What is the problem?What is the problem? What is Low Impact Development (LID)What is Low Impact Development (LID) What does LID do for that problem?What does LID do for that problem? What are some LID practices?What are some LID practices? More resourcesMore resources Questions?Questions?

Watershed Before Development

Puget Sound Action Team, WSU Pierce County Extension

The Problem: Conventional Stormwater ManagementThe Problem: Conventional Stormwater Management

Watershed After Development

Puget Sound Action Team, WSU Pierce County Extension

ADAPTED FROM SCHUELER, ET. AL., 1992, 2006ADAPTED FROM SCHUELER, ET. AL., 1992, 2006STREAM DEGRADATIONSTREAM DEGRADATION

Waterway Health & Imperviousness

8080

7070

6060

5050

4040

3030

2020

1010

00WA

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HE

D IM

PE

RV

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SN

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SW

AT

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SH

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IMP

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VIO

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NE

SS

(%)

(%)

DEGRADED

PROTECTED

IMPACTED

Parking LotsParking Lots

RoadsRoads

DrivewaysDriveways

SidewalksSidewalks

Derived from the City of Olympia, WA ISRS Final ReportDerived from the City of Olympia, WA ISRS Final Report

OfficesOfficesStoresStoresHousesHousesPatiosPatios

The Impervious Surface Budget

65% transportation

35% structures

Impacts of Conventional ApproachesImpacts of Conventional Approaches

Water quantity: too much too fastWater quantity: too much too fast Water quality: the stormwater superhighway Water quality: the stormwater superhighway

for non-point pollutantsfor non-point pollutants Costs: O & M, combined sewer overflows, etc.Costs: O & M, combined sewer overflows, etc.

Water Quantity Impacts: Flooding & ErosionWater Quantity Impacts: Flooding & Erosion

Photo and animation: National NEMO NetworkPhoto and animation: National NEMO Network

Stream erosion, Increased sediment inputs & Stream erosion, Increased sediment inputs & Increased stream temperatureIncreased stream temperature

Stormwater PollutantsStormwater Pollutants Suspended solids/sedimentsSuspended solids/sediments

Nutrients (nitrogen, phosphorus)Nutrients (nitrogen, phosphorus) MetalsMetals Oils & greaseOils & grease BacteriaBacteria Pesticides & herbicidesPesticides & herbicides Increased temperatureIncreased temperature

Can we mimic natural systems as we develop?

To better protect ourTo better protect our• StreamsStreams• Fish and wildlife habitatFish and wildlife habitat• Drinking water Drinking water • Water qualityWater quality

To reduce infrastructure To reduce infrastructure costscosts

To make our communities To make our communities more attractivemore attractive

Low Impact Development Low Impact Development plans, ordinances, and best management practices plans, ordinances, and best management practices

LID PrinciplesLID Principles

Work with the landscapeWork with the landscape Focus on prevention of stormwater runoffFocus on prevention of stormwater runoff Micromanage stormwaterMicromanage stormwater Keep it simpleKeep it simple Multi-taskMulti-task Maintain and sustainMaintain and sustain

Work with the LandscapeWork with the Landscape

It’s about living in the trees…It’s about living in the trees…

Better Site Design for PUDsBetter Site Design for PUDs

Typical Subdivision

Conservation DevelopmentConservation Development Narrow streets to Narrow streets to

reduce pavementreduce pavement Cluster units to Cluster units to

protect open spaceprotect open space Preserve existing Preserve existing

treestrees Avoid compacting Avoid compacting

soilssoils

Stein et al. 2005. Forests on the Edge: Housing Development on America’s Private Forests. USDA Forest Service.

Housing density to increase on ~44 mil. acres rural private forest (2000-2030)

Stein et al. 2005.

Planning ConstraintsPlanning Constraints State land use goals encourage State land use goals encourage

urban density urban density Encourage preservation of high Encourage preservation of high

value forestvalue forest Unintended consequence:Unintended consequence:

lack of urban forest canopy lack of urban forest canopy withinwithin Urban Growth BoundariesUrban Growth Boundaries

Minimize Clearing of Native VegetationMinimize Clearing of Native Vegetation Clearing and grading of native Clearing and grading of native

vegetation limited to the minimum vegetation limited to the minimum needed to:needed to:– Build lotsBuild lots– Allow accessAllow access– Provide fire protectionProvide fire protection

Limit of Disturbance (LOD) approx. 5 to Limit of Disturbance (LOD) approx. 5 to 10 feet from building pads10 feet from building pads

Site Fingerprinting

Protect Trees and Soil During ConstructionProtect Trees and Soil During Construction Delineate the critical root zone (CRZ): Delineate the critical root zone (CRZ):

the essential area of roots that must be the essential area of roots that must be protected for tree survivalprotected for tree survival

Install/enforce physical barriers to Install/enforce physical barriers to protect treesprotect trees

Protect soils from compaction/use soil Protect soils from compaction/use soil stockpilingstockpiling

Educate residents after constructionEducate residents after construction

The critical root zone of this tree is physically protected from compaction and damage

Photo source: The Noisette Company

Trees planted in a median strip

Trees can be incorporated into cul-de-sac islands

Expanded parking lots island with trees that share rooting space

Trees in parking lot perimeter

Collection of StormwaterCollection of Stormwater

““Efficiency” – Collect, Efficiency” – Collect, Convey, DischargeConvey, Discharge

Conventional Development

LID Development

Site Level Techniques

Swales and Rain GardensSwales and Rain Gardens

Bay City, OR

Portland, OR Boardman, OR

Green StreetsGreen Streets

Green Streets

NE Siskiyou, SW 12th and OMSI in Portland. Boardman.

Photo Koch Landscape Architecture, City of Photo Koch Landscape Architecture, City of Portland Environmental ServicesPortland Environmental Services

Photo Tom Liptan, City of Portland Environmental ServicesPhoto Tom Liptan, City of Portland Environmental Services

Bioretention in sloped areas

Planter Boxes and Street Trees

Photo Robert Emanuel, OSUPhoto Robert Emanuel, OSU

http://www.asla.org/awards/2007/07winners/517_nna.html

Pervious SurfacesPervious Surfaces

Pringle Creek, Salem, OR

Pervious pavements remove 50-98% of suspended sediments and associated particulate metals, as well as 97-99% of motor oil.

Rogue Valley Sewer Services

Alternatives to PavementAlternatives to Pavement

overflow parkingoverflow parkingconventional parkingconventional parking

Green RoofsGreen Roofs

SeQuential Biofuels, Eugene, OR

Photo Derek Godwin

Photo Robert Emanuel

Photo Derek Godwin

Rainwater HarvestingRainwater Harvesting

No permit is required to harvest up to 5,000 gallons of rainwater and use it for outdoor irrigation w/o connecting to potable plumbing.

What about the cost?What about the cost?

Kensington Estates

Total acres: 23.92

Lots: 103 (4,143 ft2 ave.)

Open space: 15 acres (63%)

Effective impervious area: ~ 0 %

Kensington Estates Cost Kensington Estates Cost ComparisonComparison

   ConventionalConventional Low ImpactLow Impact

Site PrepSite Prep $220,000$220,000 $150,000$150,000

Erosion ControlErosion Control $75,000$75,000 $25,000$25,000

Storm drainageStorm drainage $430,000$430,000 $ 150,000$ 150,000

UtilitiesUtilities $650,000 $650,000

$625,000$625,000

Road ConstructionRoad Construction $250,000$250,000 $275,000$275,000

TotalTotal $1,625,000$1,625,000 $1,225,000$1,225,000

Unit CostUnit Cost $15,777$15,777 $11,893$11,893

How to Make LID HappenHow to Make LID Happen Support stormwater management regulationSupport stormwater management regulation Re-examine local land use controlsRe-examine local land use controls Encourage open-space developmentsEncourage open-space developments Create demonstration projectsCreate demonstration projects CollaborateCollaborate

Roles for Green Industry ProfessionalsRoles for Green Industry Professionals

Arboricultural roles—tree preservation, Arboricultural roles—tree preservation, maintenance and replantingmaintenance and replanting

Bioretention—providing stock and expertiseBioretention—providing stock and expertise Hardscapes—learn about pervious pavements Hardscapes—learn about pervious pavements

and use them in designs and/or stock themand use them in designs and/or stock them Get involved—planning commissions are Get involved—planning commissions are

often sorely lacking in professional helpoften sorely lacking in professional help

Learn MoreLearn Moreextension.oregonstate.edu/watershedextension.oregonstate.edu/watershed SWAMP ProjectSWAMP Project Urban ForestryUrban Forestry Rain GardensRain Gardenswww.oeconline.org/stormwaterwww.oeconline.org/stormwater Stormwater Solutions workshopsStormwater Solutions workshops Case studies of LID projects in OregonCase studies of LID projects in Oregon LID technical resourcesLID technical resources OregonStormwater listservOregonStormwater listservblogs.oregonstate.edu/h2onc/blogs.oregonstate.edu/h2onc/bit.ly/lid4hgibit.ly/lid4hgi

Contact Information

Robert Emanuel, Ph.D.Robert Emanuel, Ph.D.OSU Extension Service FacultyOSU Extension Service FacultyWater Resources & Community Development Water Resources & Community Development 2204 Fourth Street2204 Fourth StreetTillamook, OR 97141Tillamook, OR 97141(503) 842-3433(503) 842-3433robert.emanuel@oregonstate.edurobert.emanuel@oregonstate.edublogs.oregonstate.edu/h2onc/blogs.oregonstate.edu/h2onc/