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Planning Green Infrastructure Implementation
Imagine the result
Hazem Gheith, Ph. D., P.E.
OWEA April 5, 2012
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 2
Learning Objectives
• Recognize function, types, challenges
and opportunities of Green
Infrastructure technologies in urban
area
• Recognize factors affecting the
selection of GI technologies to meet
planning objectives
• Identify datasets required for planning a
successful GI implementation program
• Understand the role of hydrology and
hydraulics modeling in assessing the
various benefits of GI
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 3
Agenda • Green Infrastructure technologies
Overview
• Factors Affecting the Selection of GI
Technologies and Required Resources
• Careful Considerations on the
Hydrology and Hydraulic Analysis of GI
Units
• Planning Green Infrastructure
Implementation Example
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
4
Rainfall Receiving
Waters
Evapotranspiration
Infiltration
Natural Storage
GI Units
Collection
System
Green Land/
natural
conditions
Urbanized land
Planning Green Infrastructure Program in Urban Area
A
B
C
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 5
Benefits of Green Infrastructure
• Reduced runoff volume means less potential for flooding and less load on stormwater or combined flow collection systems.
• Reduced velocities and peak flows protects the integrity of streams banks and reduces the occurrence of CSOs.
• Reduced pollutant loads through mitigation at the source. Leads to more streams and rivers meeting water quality standards.
• Increased recharge to groundwater reservoirs.
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
6
Rainfall Receiving
Waters
Alt 1 GI Units
Collection
System Urbanized land
Successful GI Plan
Alt 2 GI Units
Alt 3 GI Units
(1) Maximize the usage of GI
units by careful selection of
location, careful sizing, and
maximizing inflows)
Improved Condition
(2) Achieve WWF
Control Goal at key
points in the
collection system
Gravel
Soil
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 7
Possible Units for Heavy Urban Area
• Green Roofs
• Bioretention Cells
• Rain Gardens
• Urban Planters
• Porous Curbs and Gutters
• Subsurface Detention
• Bioswales
• Permeable Streets and Parking
• Rain Barrels/Cisterns
• Downspouts Disconnection
(combined flow systems)
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
8
Green Roofs • Basic function: Evapotranspiration
• Application: Vegetation on roofs
• Location: Preferably commercial
and industrial roofs for large size
and low slope
• Limitations
• Requires active involvement of
private sector
• Requires load-bearing capacity
and leak resistance
• Limited storage capacity in
plantation soil
• No infiltration to groundwater
http://www.answers.com/topic/green-roof
Gravel
Soil
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
9
Bioretention Cells • Basic function: Storage (infiltration)
• Application: Convert an impervious
surface to vegetated pervious
surface and amend natural soil with
layers of porous media
• Location: Street intersections
upstream storm inlets. Convert
portion of the side walk or parking.
• Limitations
• Special design for inlet, overflow
and under drains
• Several units for measurable
stormwater reduction in medium to
large storms
• Requires deep GW table
Gravel
Soil
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
10
Rain Gardens • Basic function: Storage (infiltration)
• Application: Excavate to amend
natural soil with layers of porous
media. Captured water infiltrates to
groundwater between storms.
• Location: Right of ways. Work
perfect if put on series (train).
• Limitations
• Special design for inlet and
overflow
• Small – requires several units for
measurable stormwater reduction
in medium to large storms.
• Requires naturally permeable soil
http://www.clemson.edu/extension/county/greenville/programs/horticulture/ra
ingarden.html
Gravel
Soil
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
11
Urban Planters • Basic function: Evapotranspiration
(infiltration)
• Application: Replace large
impervious area or poorly
vegetated area with vegetation,
without excessive excavation
• Location: Backyards, interception
of downspouts, and street medians
• Limitations
• Limited storage capacity in
planter soil
• Requires re-grading to collect
runoff into the planters Gravel
Soil
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
12
Porous Curb and Gutter • Basic function: Storage (infiltration)
• Application: Replace conventional
curb and gutter with porous
surface above a 2 to 3-foot gravel
layer for storage and infiltration.
• Location: Neighborhood and main
roads with low slop
• Limitations
• High maintenance to vacuum
fine-grain soils
• Tree roots
• No evapotranspiration
Gravel
Porous Surface
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
13
Subsurface Detention • Basic function: Storage (infiltration)
• Application: Excavate and cover a
subsurface concrete structure with
a gravel bed
• Location: Low traffic alleys at its
intersection with streets
• Limitations
• Requires load bearing capacity
• Requires low traffic conditions
• No evapotranspiration
Gravel
Porous Surface
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
14
Bioswales • Basic function: Infiltration (storage)
• Application: Long shallow surface
channels with vegetated surface.
Check dams to slow flow and
increase storage.
• Location: Roadsides with no curbs
and gutters
• Limitations
• Inconvenience to public
• Potential flooding
Gravel
Soil
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
15
Permeable Parking and Streets • Basic function: Infiltration (storage)
• Application: Replace conventional
paving material with porous surface.
• Location: Large commercial parking
side of low traffic streets
• Limitations
• Good for low traffic areas
(parking lots, sidewalks, alleys)
• High maintenance to vacuum
fine-grain soils
• Limited storage and no
evapotranspiration
Gravel
Porous surface
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
16
Rain Barrels • Basic function: Rainwater Harvesting
• Application: Collect roof runoff by
intercepting downspouts.
• Location: Residential houses
• Limitations
• Requires active involvement of private
sector (pluming and dewatering)
• Limited Storage and no
evapotranspiration or infiltration
Gravel
Soil
Water
Infiltration
Evaporation/Transpiration Runoff Overflow
Drain
dW
dS
dG
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 17
Downspout Disconnections • Basic function: Infiltration
(evapotranspiration)
• Application: Disconnect
downspouts from discharging
directly to curb lines or
combined sewers.
• Limitations
• Requires active involvement of
private sector
• Potential for inconvenient ponding
between storms
• Limited Storage
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
18
GI Units Summary
GI Type Evapo-
transpiration Storage Infiltration Limitations
Green Roof High Low None Load-bearing capacity of roofs. Leak resistance. Large commercial or
industrial roofs. Private sector involvement.
Urban Planters High Low Medium Limited storage capacity in planter soil. Limited size. Private sector
involvement.
Rain Gardens Low High Medium Requires naturally permeable soil, careful cultivation while native plants
initially become established.
Bioretention
Cells Low High Medium
Requires specially-designed inlet, overflow, and underdrain structures. Best
performance when GWT is more than 4 feet below base.
Porous
Pavements &
Curbs
None High Medium Requires low traffic areas with mild slopes. Requires high maintenance to
vacuum fine-grain soils. More depth is hindered by conflicts with utilities.
Bioswales Medium High High Requires mild slope (<6%). Best when serving small acreage area (<15 acres).
Requires larger easements than normal storm pipes.
Rain Barrels,
Cisterns None High None
Useful only if large number of neighborhood residents participates in the
program. Some maintenance is required. Freezing conditions is a problem.
Downspout
Disconnections Medium Low High
Good if local soil is permeable (2 ft+). Better if surface slope is low.
Infiltration might show up in the foundation drain. Inconvenient ponding
may occur.
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
19
GI Challenges / Concerns
• Capital Costs may be comparable to
Grey Infrastructure
• Relatively short history of operations
• Performance in terms of meeting
CWA is somewhat uncertain
• Maintenance requirements
• Public commitment
• Performance impacted by local
conditions (soils, climate, rainfall, etc.)
http://www.raingardennetwork.com/rgphotosE5.htm
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
20
Urban System Challenges
• Unique challenges:
• Limited open space
• Expensive urban lands
• Small-scale projects
• Existing utility conflicts
• Unique opportunities
• Coordination with other construction (redevelopment, roads, etc.)
• Coordination with existing parks
• Increase neighborhood life conditions
http://www.portlandonline.com/bes/index.cfm?a=77074&c=45435#photos
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 21
Agenda • Green Infrastructure technologies
Overview
• Factors Affecting the Selection of GI
Technologies and Required
Resources
• Careful Considerations on the
Hydrology and Hydraulic Analysis of
GI Units
• Planning Green Infrastructure
Implementation Example
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 22
• Factors related to the objective of the
GI program
• Pollutant removal
• Stormwater volume reduction
• Peak flow reduction
• Factors related to construction and
maintenance
• Utilities conflict, departments coordination, etc.)
• Maintenance costs
• Factors related to drainage
configuration
• Subsurface infrastructure (increasing RDII?)
• Factors related to ownership
• Public versus private properties
Factors Affecting GI Technology Selection
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 23
Factors Affecting GI Technology Selection
• Factors affecting infiltration capacity
• Permeability of local area natural soils
• Fluctuation in groundwater table
• Factors affecting the
evapotranspiration capacity
• Climatic conditions
• Local vegetation intensity and species
• Factors affecting storage capacity
• Topography and surface slope
• Availability of open spaces
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 24
Required Resources
GIS Layers
• Topography/contour lines
• Collection system network
• Streams and water bodies
• Storm (and combined) sewers
• Storm inlet points (catch basins)
• Soil maps
• Land use and impervious and
pervious areas configuration
• Orthophoto layers (Internet
Resources)
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 25
Required Resources (continued) Field Data
• Identify key hydrology and
hydraulics features of the system
• Opportunities analysis
• Open space
• Public properties (schools, parks,
street medians, etc)
• Condition of streets, curbs,
and alleys
• Wet weather condition
• Drainage quality
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 26
Required Resources (continued) Hydrology and Hydraulics Evaluation Tools:
• Urban Complex hydraulic components
• Surcharged pipes/culverts
• Backwater effects
• Pump stations
• Weirs/movable gates
• Green Infrastructure Units Complex hydraulics
• Infiltration process in layered medium
• Overflow and under drain structures
• Storage/evapotranspiration/infiltration processes
• Back to back storms
• Requires dynamic wave calculations
• SWMM family, InfoWorks, Mike Urban, etc.
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 27
Agenda • Green Infrastructure technologies
Overview
• Factors Affecting the Selection of GI
Technologies and Required
Resources
• Careful Considerations on the
Hydrology and Hydraulic Analysis of
GI Units
• Planning Green Infrastructure
Implementation Example
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 28
Catchment Surface Runoff Challenges
Sample area with Catch
basins at the intersection
• Runoff surfaces
• Garage roofs
• Lawns
• House roofs
• Drive ways
• Side walks
• Alleys
• Parking lot
• Street
1: Delineation at MH level
2: Storm Inlet level
3: Subarea level
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 29
Runoff Input Parameters
• Area
• % Impervious
• Width
• Slope
• Manning
• Depression
Storage
• Infiltration
• % Routed
Challenges with MH Catchment Level
Some Challenges
• One slope value for all
features within the
catchment
• One abstraction value for
all impervious surfaces
• One width parameter for
the sheet-flow calculation
for all subareas (pervious
and impervious features)
• Etc.
Impervious Pervious
Receiving Manhole
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 30
Traditional Delineation • One flow meter per several catchments. May achieve good
calibration - good for evaluating downstream controls (grey).
• Uncertain about runoff distribution at catchment level and inside.
20%Error:
ISE rating
ISE
R²
SEE
LSE
LSE dim
RMSE
RMSE dim
0053C2782:0053C0603
Excellent
2.32
0.938
0.576
22.2
2.59
3.41
0.19
0
1
2
3
4
5
6
7
8
9
10
11
12
0 2 4 6 8 10 12
Computed vs Observed Max Flow (mgd) at Link 0053C2782:0053C0603
Com
pute
d M
ax F
low
(m
gd)
Observed Max Flow (mgd)
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 31
Challenges with Inflows into GI Units
Backyard Planters
• Garage roofs
Train of Rain Gardens
• Garage and House roofs
• Lawns
• Part of the Street (Alleys)
• Inflow from US Rain Garden units
Porous Curb and Gutter
• All subareas, except houses DC to combined pipes
Bioretention Cells
• All subareas, except houses DC to combined pipes
Green Roofs
• Targeted Roof only
Permeable Parking
• Building roof
• Parking lot
Permeable Street
• All subareas, except houses DC to combined pipes
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 32
Enhanced Delineation
Lawns
Drive
Ways /
Streets
House
Roofs
(discon.)
Combined
Manhole
Storm
Inlet
House
Roofs
(to street)
Commerc
ial roof Parking
House
Roofs
(connect.)
Outfall
Split the catchment into subareas
representing the true runoff
configuration
• House Roofs
• Discharge onto lawns
• Discharge to the curb line
• Directly connect to combined
sewer (combined flow systems)
• Commercial roofs discharge to
parking lots
• Parking Lots discharging to collection
system
• Drive ways, alleys, and street
discharge to storm inlets
Alleys
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 33
Enhancements Improves Flow Prediction • Several parameters are known (roofs slope, roofs flow length, roofs
depression storage, streets and alley slopes and flow length, etc.)
• Faster calibration since only few parameters are up for calibration
20%Error:
ISE rating
ISE
R²
SEE
LSE
LSE dim
RMSE
RMSE dim
0053C2782:0053C0603
Excellent
1.76
0.964
0.436
12.7
1.12
2.58
0.144
0
1
2
3
4
5
6
7
8
9
10
11
12
13
0 2 4 6 8 10 12
Computed vs Observed Max Flow (mgd) at Link 0053C2782:0053C0603
Com
pute
d M
ax F
low
(m
gd)
Observed Max Flow (mgd)
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
34
Better Understanding of Flow Configuration
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
5AM
Jun 14 Sat 2008
6AM 7AM 8AM 9AM
Link 0086C0132:0086C0133
Flo
w (
mgd)
Date/Time
DoeAlley_NewDelineation 0086C0132:0086C0133 DoeAlley_Recal_Hazem
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 35
Educated Prioritization of Catchments for GI Implementation • Locate inlet catchments
with higher flow
contribution
• Select optimum location
for GI units to maximize
benefit
• Achieve control goal at
much less cost
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 36
Agenda • Green Infrastructure technologies
Overview
• Factors Affecting the Selection of GI
Technologies and Required
Resources
• Careful Considerations on the
Hydrology and Hydraulic Analysis of
GI Units
• Planning Green Infrastructure
Example
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
37
H/H Analysis of GI Units Example: Combined flow collection basin.
Use GI units to reduce volume and peak
flow.
• Based on GI unit type, it can be placed
at certain locations within the study
area. Hence, they will impact different
portions of the runoff catchment.
• It is important to have a reasonably
detailed representation of hydrology
features of the runoff catchment.
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 38
Example H/H Analysis of GI Units
Total catchment area = 5 acres
• Roof tops = 1.5 acres
• 0.9 acres: roofs with disconnected
downspouts
• 0.3 acres garages
• 0.6 acres houses
• 0.15 acres: roofs discharge to street
• 0.15 acres: roof commercial discharges to
parking area
• 0.3 acres: roofs directly connected to
combined sewers
• Pervious lawns = 2.6 acres
• 1 acre backyards
• 1.6 acre side and front yards
• Impervious ground surface = 0.9 acres
• 0.25 acres parking lots
• 0.65 acres street and driveways
Back
yards
(1 ac)
Side /
Front
(1.6
ac)
Drive
Ways /
Streets
(0.65 ac)
Garage
(0.3 ac)
Houses
(disconn.)
(0.6 ac)
Combined
Manhole
Storm
Inlet
Houses
(to street)
(0.15 ac)
Commerc
ial roof
(0.15 ac)
Parking
(0.25
ac)
Houses
(connect.)
(0.3 ac)
Outfall
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 39
Example H/H Analysis of GI • Test design storm
• 24-hours SCS Type II (2.17 in)
• Evaporation rate = 0.1 in/day
• Natural soil infiltration parameters:
(Binnington)
• Permeability = 0.06 in/hour
• Suction head = 11 inches
• Moisture deficit = 0.1
• Results for base Condition:
• Peak flow = 2.7 MGD
• Runoff volume = 0.14 MG
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 40
Planters • Assumptions:
• Location: Each backyard
(26 x 10’ x 10’)
• Configuration: 6” of vegetated soil
• Outflow Peak flow = 2.59 MGD (-5.6%)
• Outflow Volume = 0.14 MG (-1.4%)
Back
yard
Side /
Front
Yard
Drive
Ways /
Streets
Garage
Houses
(disconn.)
Combined
Manhole
Storm
Inlet
Houses
(to street)
Commerc
ial roof Parking
Houses
(connect.)
Outfall
Planters
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 41
Green Roof • Assumptions:
• Location: Commercial roof (0.25 acres)
• Configuration: 4” of vegetated soil
• Peak flow = 2.63 MGD (-4.1%)
• Volume = 0.13 MG (-6.3%)
Back
yard
Side /
Front
Yard
Drive
Ways /
Streets
Garage
Houses
(disconn.)
Combined
Manhole
Storm
Inlet
Houses
(to street)
Parking
Houses
(connect.)
Outfall
Comm.
roofs
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 42
Rain Gardens • Assumptions:
• Location: ROW (2 trains, 6 x 3’ x 10’)
• Configuration: 18” gravel topped
with 12” of vegetated soil.
• Peak flow = 2.72 MGD (-0.6%)
• Volume = 0.14 MG (-3.6%)
Back
yard
Side /
Front
Yard
Drive
Ways /
Streets
Garage
Houses
(disconn.)
Combined
Manhole
Storm
Inlet
Houses
(to street)
Commerc
ial roof Parking
Houses
(connect.)
Outfall
Street
RG
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 43
Bioretention Cells • Assumptions:
• Location: Road intersection
(2 sides, 6’ x 30’ each)
• Configuration: 18” gravel topped with 6” of
vegetated soil, topped with a 12” detention
• Peak flow = 2.74 MGD (-0.07%)
• Volume = 0.14 MG (-1.4%)
Back
yard
Side /
Front
Yard
Drive
Ways /
Streets
Garage
Houses
(disconn.)
Combined
Manhole
Storm
Inlet
Houses
(to street)
Commerc
ial roof Parking
Houses
(connect.)
Outfall
BRC
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 44
Porous Curb & Gutter • Assumptions:
• Location: Road side (2 x 2.5’ x 1400’)
• Configuration: 30” gravel topped
with 6” of permeable concrete
• Peak flow = 1.41 MGD (-49%)
• Volume = 0.13 MG (-7.8%)
Back
yard
Side /
Front
Yard
Drive
Ways /
Streets
Garage
Houses
(disconn.)
Combined
Manhole
Storm
Inlet
Houses
(to street)
Commerc
ial roof Parking
Houses
(connect.)
Outfall
P
C
G
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 45
Permeable Pavement - Street • Assumptions:
• Location: Public street (0.65 acres)
• Configuration: 9” gravel topped
with 3” of permeable surface
• Peak flow = 0.76 MGD (-72.1%)
• Volume = 0.07 MG (-51.1%)
Back
yard
Side /
Front
Yard
Permeable
Streets
Garage
Houses
(disconn.)
Combined
Manhole
Storm
Inlet
Houses
(to street)
Commerc
ial roof Parking
Houses
(connect.)
Outfall
Drive
ways
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 46
Permeable Pavement - Parking Lot • Assumptions:
• Location: Commercial parking (0.25 acres)
• Configuration: 12” gravel topped
with 3” of permeable surface
• No under drain assumed
• Peak flow = 2.5 MGD (-8.6%)
• Volume = 0.12 MG (-15.6%)
Back
yard
Side /
Front
Yard
Drive
Ways /
Streets
Garage
Houses
(disconn.)
Combined
Manhole
Storm
Inlet
Houses
(to street)
Commerc
ial roof Parking
Houses
(connect.)
Outfall
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 47
Rain Barrels • Assumptions:
• Location: All garages and houses
(56 roofs x 2 barrels per roof)
• Configuration: 60 gallons barrels (24” x 39”)
• Peak flow = 2.73 MGD (-0.3%)
• Volume = 0.14 MG (-4.3%)
Back
yard
Side /
Front
Yard
Drive
Ways /
Streets
Garage
Houses
(disconn.)
Combined
Manhole
Storm
Inlet
Houses
(to street)
Commerc
ial roof Parking
Houses
(connect.)
Outfall
RB
RB
RB
RB
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
48
Design Storm Summary Results
GI Units
Design
Storm
Peak Flow
Reduction
Design
storm
Volume
Reduction
Green Roof 4.1% 6.3%
Planters 5.6% 1.4%
Rain Gardens 0.6% 3.6%
Bioretention Cells 0.07% 1.4%
Porous Curb and
Gutter 49% 7.9%
Porous Pavement
(Street) 72.1% 51.3%
Porous Pavement
(Parking Lot) 8.6% 15.6%
Rain Barrels 0.3% 4.3%
Imagine the result
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
49
Typical Year Storms Results
GI Units
Typical Year
Volume
Removed
(gallons)
Typical Year
Percentage
Volume
Reduction
GI Cost
Dollar amount
per gallon
removed
Green Roof 138,000 7.8% $99,186 $0.71
Planters 27,000 1.5% $9000 $0.33
Rain Gardens 116,000 6.6% $14400 $0.12
Bioretention Cells 88,000 5% $10,800 $0.12
Porous Curb and
Gutter 419,000 23.7% $252,000 $0.50
Permeable Street 1,151,000 65% $318,860 $0.28
Permeable Parking 370,000 20.9% $108,900 $0.29
Rain Barrels 163,000 9.2% $36,960 $0.23
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 50
Example H/H Analysis of GI
Consideration on the results
• Careful field investigation and hydrology and
hydraulics analysis are keys for a successful green
infrastructure implementation planning.
• Environmental and Social impacts (TBL)
• Life cycle cost consideration
• Water Quality constraints can affect the prioritization of
the selected GI technologies
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 51
Learning Objectives Revisited
• Recognize function, types, challenges
and opportunities of Green
Infrastructure technologies in urban
area
• Recognize factors affecting the
selection of GI technologies to meet
planning objectives
• Identify datasets required for planning a
successful GI implementation program
• Understand the role of hydrology and
hydraulics modeling in assessing the
various benefits of GI
Planning Green Infrastructure Implementation, OWEA April 5, 2012 © 2012 ARCADIS
Imagine the result 52
Q&A
Hazem Gheith, Ph. D., PE
614.888.4953 (office)