why low impact development pccpac
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Presentation to the Pacific City Woods CPAC on 4/16/2011. Please contact author for permission to use all or part of this presentation.TRANSCRIPT
What’s so Bad about Stormwater & What Does Low Impact Development Do About It?
Robert Emanuel, Ph.D.Oregon State University
Oregon Sea Grant Extension
“We forget that the water cycle and the life cycle are one.” --Jacques Cousteau
Where is your community in the watershed?
Puget Sound Action Team, WSU Pierce County Extension
Puget Sound Action Team, WSU Pierce County Extension
Video by Laura James, Seattle, WA
Photo: Motoya Nakamura/The Oregonian
Impacts of Conventional Approaches
Water quantity: too much too fast Water quality: the stormwater superhighway
for non-point pollutants Costs: O & M, combined sewer overflows, etc.
Flooding and Urban Development
More Runoff
Arriving Faster
Time, hours
Flow
Rat
e, c
fs
Water Quantity Impacts: Flooding & Erosion
Stormwater Pollutants Suspended solids/sediments Nutrients (nitrogen, phosphorus) Metals (copper*, lead, zinc, cadmium, mercury) Oil & grease* Cleaning chemicals Detergents or soaps Bacteria Pesticides* Increased temperature
*Recent studies show link between these pollutants and salmonid olfactory disorientation and pre-spawning mortality.
Parking LotsRoadsDrivewaysSidewalks
Derived from the City of Olympia, WA ISRS Final Report
OfficesStoresHousesPatios
The Impervious Surface Budget
65% transportation
35% structures
To better protect our watersheds
To reduce infrastructure costs
To make our communities more attractive
Low Impact Development plans, ordinances, and best management practices
Slide: Chesapeake NEMO
Slide: Chesapeake NEMO
Slide: Chesapeake NEMO
Slide: Chesapeake NEMO
Slide: Chesapeake NEMO
Slide: Chesapeake NEMO
Slide: Chesapeake NEMO
Pringle Creek Development in Salem
Kensington Estates
Total acres: 23.92
Lots: 103 (4,143 ft2 ave.)
Open space: 15 acres (63%)
Effective impervious area: ~ 0 %
Kensington Estates Cost Comparison
Conventional Low Impact
Site Prep $220,000 $150,000
Erosion Control $75,000 $25,000
Storm drainage $430,000 $ 150,000
Utilities $650,000
$625,000
Road Construction $250,000 $275,000Total $1,625,000 $1,225,000
Unit Cost $15,777 $11,893
Slide: Chesapeake NEMO
Slide: Chesapeake NEMO
Site Practices
© Good Nature Publishing
A rain garden is a “sunken garden bed” that collects & treats stormwater runoff from rooftops, driveways, sidewalks, parking lots & streets.
Graphic: EMSWCD
How a Rain Garden Works
Graphic: EMSWCD
Portland Community College, Portland OR
Bay City, OR
Port Orford, OR Photo: Frank Burris, OSU
Glencoe Elementary School, Portland, OR
Photo Koch Landscape Architecture, City of Portland Environmental Services
http://www.asla.org/awards/2007/07winners/517_nna.html
NE 36th and Emerson, Portland
Moving water across a sidewalk Photo courtesy of Portland Environmental Services
Other Practices
Gravel Wetland
Green Street Planters
SW 12th @ Montgomery (PSU)
Pringle Creek, Salem, OR
Rogue Valley Sewer Services
Shorebank Pacific, Ilwaco, WA
SeQuential Biofuels, Eugene, OR
Photo Robert Emanuel
Photo Derek Godwin
What do these strategies cost?
What strategies yield greatest benefits?
What strategies help build resilience?
Not all pollution is the same:
1. Site Planning/Land Use2. Controlling Sources3. Site-level Practices
Effectiveness
How to Make All of This Happen
Pass stormwater management regulationRe-examine local land use controlsPermit and promote open-space developmentsUse landscape features instead of infrastructureCreate demonstration projectsCollaborate!
Robert Emanuel, Ph.D.OSU Extension Service FacultyWater Resources & Community Development 2204 Fourth StreetTillamook, OR 97141(503) 842-5708 X 210
[email protected]/h2onc/