2010 07-16 orcca minicharrette - copy

ORCCA Mini-charrette meetingJul 16, 2010

Courtesy of Scott Edwards Architecture

The Water Balance Model: typical for CascadiaWater Quantity Before

16.5” interflow(infiltration)

26” e

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0.2” runoff

65” r

ain

fall

yearl

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22” g

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nd

wate

r(i

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tion

)

The Water Balance ModelWater Quantity After

0” baseflow(infiltration)

red

uced

evap

o-

tran

sp

irati

on

63” runoff65” r

ain

fall

yearl

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2” e

vap

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Red

uced

infi

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tion

Impervious SurfacesA Watershed Perspective

The Water Balance ModelWater Quality Before

Some sediment

The Water Balance ModelWater Quality After

Sediment (air particulates), dissolved

pollutants (nitrogen, zinc), heavy metals, Feces, Temperature,

other debris

Sediment/turbidity,

Hydrocarbons, Heavy metals, temp, feces,

other chemicalsSediment/turbidity

fertilizers, pesticidesherbicides,

feces, heavy metals

Air

Soil

Image from Soil Quality Information Sheet, U.S. Department of Agriculture

Best Management Practices (aka BMPs)Two Types

N

ORCCA’s Priority List – reorganizedFILTRATION

• Bioretention/rain gardens

• Vegetated swales• Vegetated filter

strips• Wetland

preservation

Structural BMPsInfiltration and Water Quality

Water quality benefits of infiltration techniques from the “National Pollutant Removal Performance Database for Stormwater Treatment Practices” Center for Watershed Protection, June 2000

PollutantInfiltrati

on

SW Wet-land

Wet Pond Filtering

WQ Swale

Dry Pond

Total Phosphorus

70 49 51 59 34 19

Soluble Phosphorus

85 35 66 3 38 -6

Total Nitrogen 51 30 33 38 84 25

Nitrate 82 67 43 -14 31 4

Copper N/A 40 57 49 51 26

Zinc 99 44 66 88 71 26

Total Suspended Solids

95 76 80 86 81 47

ORCCA’s Priority List – reorganizedRUNOFF REDUCTION

Infiltration• Trenches• Rain gardens &

other vegetated treatment systems

• Porous pavement• Disconnected

downspoutsEvaporation• Eco-roof

Reuse• Cisterns for parking

lot, street, sidewalk, and roof storage

Additional suggestions:

• Limit disturbance• Save trees

Infiltration trenches are a UICnot recommended for our timeline

Rain Gardens

Other vegetated systems: Planters

Other vegetated systems: Vegetated Filter Strips

Pervious pavements: Use with CAUTION here

POROUS ASPHALT IN 1- 2” LIFT

UNCOMPACTED SUBGRADE

NON-WOVEN PROPYLENE GEOTEXTILE

12”

1-1/2” to 1” WASHED CRUSHED AGGREGATE

3”

Downspout Disconnection

Eco-roofs

Cisterns for parking lot, street, sidewalk, and roof storage

ORCCA’s Priority List – additional BMPsRUNOFF REDUCTION

• Trellises and other vertical vegetation

• Limit disturbance• In Planning• Save a tree in design• In construction

• Minimize impervious surfaces

Trellises & other vertical vegetation

Trellises & other vertical vegetation

Limit Disturbance in Planning

Limit Disturbance in DesignSave a Tree

Limit DisturbanceConstruction Practices

Limit DisturbanceConstruction Practices: Don’t cement treat the

soil

Minimize impervious surfaces

ORCCA’s Priority List – reorganizedSTORAGE (aka Peak Flow Attenuation)

Caution: Storage for peak flow attenuation is not necessarily LID but will help us argue against the detention pipe.

• Depressional storage in landscape islands and in tree, shrub, or turf depressions = runoff reduction through infiltration and treatment

• Storage in wetland• Compost amendment and other soil

restoration practices

Storage in wetland at Oleson Woods Apts

ORCCA’s Priority List: additional BMPsSTORAGE (aka Peak Flow Attenuation)

• Compost amendment and other soil restoration practices

Compost Amendment & other soil restoration practices

Photos on left are from Soils for Salmon website

ORCCA’s Priority List – reorganizedCONVEYANCE

• Eliminate curbs & gutters

• Swales• Roughening

surfaces• Long overland flow

paths over landscaped areas

• Installing smaller culverts, pipes, & inlets

• Creating terraces and check dams

Eliminate curb & gutter

Eliminate curb & gutter

Swales & daylighting

Swale & DaylightingDetails

Swale & DaylightingDetails

Check dams

ORCCA’s Priority List: additional BMPsCONVEYANCE

• Don’t impede subsurface flows.

• Use treatment trains to extend the life of the vegetated facilities.

Transportation BMPsTraffic calming woonerf

Photo from Techniques for Urban Sustainability website

Additional BMPs: Source Control

Additional BMPsSource Control in Construction

Additional BMPsSource Control in Construction

Photo excerpted from “BMPs for Stormwater Discharges Associated with Construction Activities”, DEQ, Feb 2006

Additional BMPsSource Control in Construction

Photos and study and text excerpted from “BMPs for Stormwater Discharges Associated with Construction Activities”, DEQ, Feb 2006

Additional BMPsSource Control Post Construction

Biodiversity

Siting Consideration

N

Additional BMPs discussed but no photos

• More landscape practices• Water use• Source control• Materials• Operations &

Maintenance• Social Goals• Passive Solar Design• Construction Management

ORCCA Mini-charrette meetingJul 16, 2010

Sustainability for all the places between the buildings.