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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
TE
RS
HE
D IM
PE
RV
IOU
SN
ES
SW
AT
ER
SH
ED
IMP
ER
VIO
US
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) [email protected]@oregonstate.edublogs.oregonstate.edu/h2onc/blogs.oregonstate.edu/h2onc/