Transcript Module 9: Intro to Facility Design

Module 9: Intro to Bioretention Design
Frank Lopez, PE, QSD/P
Rick Engineering Company
Bioretention Design
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What is Bioretention? (recap)
Manufactured Bioretention Systems
Bioretention Design Criteria
Project Scenarios
Bioretention Design
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What is Bioretention? (recap)
Manufactured Bioretention Systems
Bioretention Design Criteria
Project Scenarios
What is Bioretention?
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Shallow depressions located in upland areas
Capture and temporarily store stormwater
Surface and sub-surface water filtration system
Treatment Train Incorporates:
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surface ponding area
plants & mulch,
engineered soils,
filter fabric
gravel bed
potential underdrain
Image Courtesy of Prince George County
Bioretention Facilities
Bioretention
Bioretention facilities are
landscaped shallow
depressions that capture
and filter stormwater.
These facilities function as
a soil and plant-based
filtration devices and are
used when the
surrounding soils permit.
Image Courtesy of City of Los Angeles
Bioretention Facilities
Hybrid Bioretention/Dry Wells
A bioretention facility with dry
wells is useful in areas with low
surface-level hydraulic
conductivities that would
normally deem a bioretention
BMP infeasible but have higher
levels of permeability in deeper
strata
Image Courtesy of City of Los Angeles
Bioretention Facilities
Bioretention w/Underdrain
A bioretention facility with an
underdrain system is useful in
areas with low surface-level
hydraulic conductivities. The
facility can be lined with geotextile fabric due to site
constraints.
Image Courtesy of City of Los Angeles
Bioretention Facilities
Planter Box
Planter boxes are bioretention
treatment control measures
that are completely contained
within an impermeable
structure with an underdrain
(they do not infiltrate). They are
similar to bioretention facilities
with underdrains except they
are situated at or above ground
and are bound by impermeable
walls. Planter boxes may be
placed adjacent to or near
buildings, other structures, or
sidewalks.
Image Courtesy of City of Los Angeles
Bioretention Facilities
Bioinfiltration
Bioinfiltration facilities are
designed for partial infiltration of
runoff and partial biotreatment.
These facilities are similar to
bioretention devices with
underdrains but they include a
raised underdrain above a gravel
sump designed to facilitate
infiltration. These facilities can be
used in areas where there are little
to no hazards associated with
infiltration, but infiltration
screening does not allow for
infiltration BMPs due to low
infiltration rates or high depths of
fill.
Image Courtesy of City of Los Angeles
Bioretention Design
•
•
•
•
What is Bioretention? (recap)
Manufactured Bioretention Systems
Bioretention Design Criteria
Project Scenarios
Manufactured Bioretention
Systems
www.filterra.com
Manufactured Bioretention
Systems
www.modularwetlands.com
Manufactured Bioretention
Systems
www.conteches.com
Bioretention Design
•
•
•
•
What is Bioretention? (recap)
Manufactured Bioretention Systems
Bioretention Design Criteria
Project Scenarios
Bioretention Design Criteria
• What are the design parameters?
– Most agencies have sizing criteria specific to
bioretention facility design.
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Ponding depth limits (12”-18”)
Drawdown time (Surface = 24-72 hours; Subsurface = 96 hrs)
Treatment and evaporation surface area (4% - 6% DMA)
Max tributary drainage area
Engineered soil media infiltration rate (long term rate = 5 in/hr)
Water quality volume reduction (85th - 95th Percentile Storm)
Water quality flow treatment (I = 0.2 in/hr or 2x 85th Percentile)
Bioretention Design
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What is Bioretention? (recap)
Manufactured Bioretention Systems
Bioretention Design
Project Scenarios
Project Scenario #1
Parking Lot
Expansion
Project Information:
• Project Area = 3.0
acres
• Type A Soil
• Setback
Requirements
• No storm drain
LID Components:
• Pervious
Pavement
• Bioretention
Project Scenario #1
Parking Lot
Expansion
Project Information:
• Project Area = 3.0
acres
• Type A Soil
• Setback
Requirements
• No storm drain
LID Components:
• Pervious
Pavement
• Bioretention
Project Scenario #1
Project Scenario #1
Project Scenario #1
See anything wrong?
Project Scenario #1
See anything wrong?
Ponded water on a sunny day.
The facility was compacted during
construction.
Project Scenario #1
Project Scenario #1
Project Scenario #2
Parking
Garage/Commercial
Redevelopment
Project Information:
• Project Area = 0.7 acres
• Subterranean Parking
• Cannot Infiltrate
LID Components:
• Cistern to Bioretention
Project Scenario #2
Project Scenario #2
Project Scenario #2
Project Scenario #2
Project Scenario #2
Project Scenario #2
Project Scenario #2
Cistern
THE END
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