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This PowerPoint describes each best practice, description of challenging sites, conveyances and flows, permitting, O&M
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Stormwater Practices for Challenging Sites
Sustainability for all the places between the buildings
cell [email protected] certified women business enterprise
What I’m About to Tell You
How Residents Can Safely Manage Stormwater•Housekeeping•What’s a “Challenging Site”?•Why do our properties impact water quality?•Why is reducing runoff important?•What practices can we implement on our own properties?
About Me
About You
Challenging Sites are…
… any area not suitable for infiltration of runoff.
This includes:• Steep slopes/landslides• Clay soils• High seasonal groundwater• Inadequate setbacks
(ex. Buildings too close together)
The Water Balance ModelWater Quantity Before
25% baseflow(infiltration)
50%
evap
ora
tion
0.5% runoff
100%
avera
ge
An
nu
al ra
infa
ll
25%
gro
un
dw
ate
r(i
nfi
ltra
tion
)
Water Balance BEFORE DevelopmentSimplified
The Water Balance ModelWater Quantity After
0” baseflow(infiltration)
red
uced
evap
o-
tran
sp
irati
on
100%
rain
fall
yearl
y a
vg
98% runoff
2%
evap
o-
tran
sp
irati
on
Red
uced
infi
ltra
tion
Water Balance AFTER DevelopmentExample: EVERYWHERE
“Before” & “After” Runoff Compared
0.5% runoff
98% runoff
Runoff: A Watershed Perspectivein the West Hills
• Flooding, landslides and stream bank erosion
The Water Balance ModelWater Quality Before
Some sediment
The Water Balance ModelWater Quality After
Sediment (air particulates)Nutrients
FecesOther debris
Sediment/turbidityHydrocarbons
Heavy metals (particles & soluble)Other chemicalsRunoff volume
Sediment/turbidityfertilizerspesticidesherbicides
Runoff volume
13
Restore the Soil: Lawn Areas
Runoff prevented = 50%
Restore the Soil: Perennial Garden Areas
Runoff prevented = 80%
Restore the Soil: Meadows
Runoff prevented = 65%
Compost Amended SlopesWashington DOT
• Great for keeping soil in place on steep slopes, too!
http://www.wsdot.wa.gov/Design/Roadside/SoilBioengineering.htm
Lots of great information atsoilsforsalmon.org
Contained Planters (Over Hardscapes)
Contained Planters (Over Impervious Area)
Runoff prevented = 50%
Minimize Impervious PavementDepaving
Runoff prevented varies depending on what replaces the pavement, lawn or perennial garden.
Lots of great information atdepave.org
Tree Planting
Porous Walkway & Patio Surface Types
Homemade pavers
Grass-crete
Flexible Pavements (GrassPave )
Commercial pavers
Boardwalks/decks
Wood chips (pedestrian only)
Gravel
Typical Permeable Paver Section
Porous Walkways
Runoff prevented =
90%
Ecoroof/Green Roofs?
• DIY Projects = areas where a single ply of impermeable lining can be used or where failure isn’t too problematic
Ecoroof/Green Roof
Runoff prevented = 50%
Conveyances & Flows
Issues to look for
• Drainage problems, like water pooling in your yard.• Bare spots
Issues to look for
• Erosion: Stream banks
Issues to look for
• Erosion: Garden areas
Historic Landslide AreasOne way to identify them
• Erosion: Landslides
Bent trunks sometimes indicate areas where landslides occurred a long time ago = likely to happen again
Permitting
Operations & Maintenance
What I Just Told You
How Residents Can Safely Manage Stormwater•Housekeeping•What’s a “Challenging Site”?•Why do our properties impact water quality?•Why is reducing runoff important?•What practices can we implement on our own properties?
Thank You!
Rain Barrels
Rain Barrels: Food for Thought
Rain Barrels: Landscape
Rainwater Harvesting: L andscapesA Watershed Perspective
Rainwater Harvesting: Indoor Uses
