Gordon’s winning Green Roadway LID Design Competition presentation. This presentation is a 5 minute timed slide show and was presented at VMI’s 23rd Annual Environment Virginia Symposium. The competition was funded through a grant from the National Fish and Wildlife Foundation and the project sponsors included James River Association, Friends of the Rappahannock, and Potomac Conservancy.

1. Balancing
Nature & Neighborhood 1
1

2. Design
Process 2
Site Base Review Design Final
Establish
Brainstorm Goals Concept
Visit map Requirements priorities details Design
Balance of professionals
• Landscape Architects
• Civil Engineers

3. Existing
Residential Neighborhood 3
• 17 residences and only14 driveways
• Unrestricted on-street parking for a total of 39 +/- spaces
• The road is crowned with a single low point
• Existing trees do not form a consistent tree canopy

4. Existing
Parking 4
Zoning Requirements
Single family dwellings:
1 space/ residence
Existing Parking:
14 Driveway Spaces: 14 spaces
On Street Spaces: 39 spaces
Total Spaces: 53 spaces
Existing Parking Ratio: 3.1 spaces/ residence

5. LID
Strategies 5
Our team explored a variety of LID techniques before
determining the best LID measures that seemed fitting for
the existing conditions of this neighborhood.
These included:
• Decrease impervious area
• Converting pavement into bio-retention areas
• Use pervious pavement
• Reduce traditional storm water infrastructure
• Encourage parking in existing paved areas
• Use of native/ adapted plants
• Use decentralized LID’s

6. LID
Strategies 6

7. LID Strategies
Site Plan 7
Zoning Rqmt : 1 space/residence
Existing Parking:
14 Driveway Spaces: 14 spaces
On Street Spaces: 39 spaces
Total Spaces: 53 spaces
Existing
Parking Ratio: 3.1 spaces/ residence
Proposed Parking:
14 Driveway Spaces: 14 spaces
On Street Spaces: 30 spaces
Total Spaces: 44 spaces
Proposed
Parking Ratio: 2.6 spaces/ residence
Loss of 9 on-street parking spaces

8. LID Strategies
Landscape Plan 8
• Overhead power lines on North
side of street
• Use of small to medium street trees
• Uniform street tree canopy to
compliment existing trees

9. Landscape Palette
9
Liquidamber styraciflua ‘Rotundiloba’
(Rotundiloba Sweetgum)
Betula nigra
Nyssa sylvatica Red Maple (River Birch)
(Black Tupelo) (Acer rubrum)
Gleditsia triacanthos inermis ‘Imperial’
(Imperial Honeylocust)
Myrica pensylvanica
(Northern Bayberry)
Clethra alnifolia ‘Hummingbird’
(Sweet Pepperbush)
Ilex glabra ‘Shamrock’
(Shamrock Inkberry)
Spireae tomentosa Ilex verticillata ‘Nana’
(Steeplebush) (Red Sprite Winterberry)
Eupatorium fistulosum Phlox stolonifera Aster divaricatus
(Joe Pye Weed) (Creeping Phlox) (Dwarf Aster)
Deschampsia caespitosa
Iris versicolor
(Tufted Hairgrass)
(Harlequin Blueflag)
Native, low maintenance, and durable in urban
and bioretention environments

10. Balancing
Nature & Neighborhood 10
• Using Stormwater to provide Neighborhood character
• Attractive and native landscaping
• Interconnected LID practices

11. LID Strategies
Bioretention Planting 11

12. 12
LID Strategies
Bioretention

13. LID Strategies
Pervious Pavement 13
The Green Roadway
converts asphalt into
pervious pavement.
Bioretention planters are
used in series and
interconnected through
an underdrain system.

14. LID Strategies
SWM (Quantity Control) 14
Highlights Design Event Scenario
Peak
Discharge
Peak Discharge Reduction
Percentage (Green VS.
(cfs) Existing)
• No reliance on infiltration, applicable to any
Forested Condition 2.23
soil condition
5 -yr Existing Condition 5.13 58.48%
• No Adjusted/ reduced Curve Numbers due Green Roadway 2.13
to pervious pavement or runoff reduction
• No Flooding: 100-YR Runoff is contained
Peak Peak Discharge Reduction
Design Event Scenario Discharge Percentage (Green VS.
(cfs) Existing)
within LID practices
Forested Condition 3.15
10-yr Existing Condition 6.17 61.91%
Green Roadway 2.35
12.00
Peak Peak Discharge Reduction
Design Event Scenario Discharge Percentage (Green VS.
100-YR Storm Hydrographs (cfs) Existing)
10.00
Forested Condition 7.67
Existing Condition 100-yr Existing Condition 10.79 73.86%
8.00
Green Roadway 2.82
Discharge (cfs)
Green Roadway
6.00
4.00
2.00
0.00
540 600 660 720 780 840 900

15. LID Strategies
SWM (Quality Control) 15
Summary
Phosphorus Removal (based on Virginia Runoff Reduction Worksheet)
Highlights
Phosphorus Phosphorus Leaving the Site
Phosphorus Removed Phosphorus Phosphorus
Phosphorus Load Removed by Reduction Percentage
Scenario by Pervious Pavement Leaving the Site Removal
Bioretention (Green Roadway VS. Existing
(lb/yr) (lb/yr) (lb/yr) (lb/yr)
Percentage
Condition) • 90% Phosphorus
Existing Condition 1.79 0.00 0.00 1.79 0% removal
Green Roadway 1.64 0.50 0.96 0.18 89%
90%
• Approach utilized
Nitrogen Removal (based on Virginia Runoff Reduction Worksheet) Runoff Reduction
Nitrogen Load
Nitrogen Removed by Nitrogen Removed Nitrogen Nitrogen
Nitrogen Leaving the Site Reduction Methodology
Pervious Pavement by Bioretention Leaving the Site Removal Percentage
Scenario
(Green Roadway VS. Existing
Percentage
(lb/yr) (lb/yr) (lb/yr) (lb/yr) Condition)
Existing Condition 12.77 0.00 0.00 12.77 0%
91% • Phosphorus and
Green Roadway 11.70 3.55 6.99 1.16 90%
Nitrogen reductions
helps meet Bay
Runoff Reduction (based on Virginia Runoff Reduction Worksheet) TMDLs
Treatment Volume Runoff Leaving the Site Reduction
Runoff Reduced by Runoff Reduced by Runoff Leaving Runoff
(Runoff from 1" Percentage
Scenario Pervious Pavement Bioretention the Site Reduction
Rainfall) (Green Roadway VS. Existing
Percentage
(cf) (cf) (cf) (cf) Condition)
Existing Condition 2,841 0 0 2,841 0%
Green Roadway 2,603 605 1,503 495 81% 83%

16. Cost Analysis
16
$600,000
Highlights
LID
Conventional • Conventional Cost
assumed use of a
$500,000
conventional sand
filter for Quality
$400,000
Control and an
underground
$300,000 concrete vault for
Quantity Control.
$200,000
• Conventional Cost
$100,000 resulted in additional
cost for pavement
$-
and storm drainage
Site Pavement Curb, Edging Storm Landscaping Total systems
Preparation and Sidewalks Drainage
Systems
• LID Design resulted in
increased costs for
The LID Design resulted in savings of $125K for 715LF
curbing and
of roadway construction. landscaping.

17. Conclusion
17
• innovative design, real world solution through
interconnected decentralized facilities
• Enhanced quality of life through landscaping
• mimics natural hydrologic function of the site
and will help meet Bay TMDL’s
• lower construction costs compared to
conventional design