The document summarizes a community meeting to discuss the conceptual design for the Huntington Levee project. The meeting covered the project background and flooding issues facing the community. It then reviewed the conceptual design features being considered, including the use of collection drains versus a cutoff wall, different locations for a pump station, options for stormwater diversion, and use of an earthen levee alone or in combination with an I-wall. The design aims to meet FEMA accreditation standards to reduce flooding and received feedback from the community.

1. Huntington Levee
Community Meeting
January 16, 2014
Building Design Branch
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2. Purpose of Meeting
• Review levee conceptual design features and
recommendations
• Receive feedback from the community on project
features before moving forward with final design
Building Design Branch
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3. Agenda
I.
Project Background
II. Conceptual Design Features
III. Accreditation
IV. Questions
Building Design Branch
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4. Project Background
• June 2006 -160 homes
were flooded from a
storm event
• 2009 – US Army Corps
of Engineers (USACE)
completed a study to
evaluate flood
damage reduction
measures in the
Huntington
Community
Building Design Branch
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5. Project Background
• September 2011- Tropical Storm Lee caused
damage to 160 homes in the Huntington Community
• November 6, 2012 – Fairfax County voters approved
stormwater bond referendum to fund design and
construction of flood damage reduction measurers
• November 9, 2012 – Fairfax County advertised for
consultant design services
• June 2013 – Fairfax County awarded the levee
design contract to ARCADIS
Building Design Branch
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6. Project Background
Building Design Branch
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7. Project Background
• November 2013 – ARCADIS submitted the Phase I
design package to Fairfax County
• Survey – 300 acre of aerial survey, 80 acre field survey, 26
field run cross sections of Cameron Run, utility survey
• Geotechnical Investigation – collection and analysis of 13
additional soil borings
• Wetland delineation
• Conceptual Design
• Review USACE 2009 study and conceptual design
• Evaluate potential refinements/alternatives
Building Design Branch
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8. Project Background
• Phase II (January 2014-Winter 2017)
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•
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•
•
Schematic Design (30%)
Design Development (60%)
Permitting
Land Acquisition
Construction Documents (100%)
Bidding
• Phase III (Winter 2017-Spring 2019)
• Construction
• Original schedule condensed by 7 months
Building Design Branch
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9. Conceptual Design Features
Key Design Considerations
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Collection Drains vs. Cut Off Wall
Pump Station Location
Stormwater Diversion
Earthen Levee vs. Earthen Levee/I-Wall Combination
Building Design Branch
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10. Collection Drains vs. Cutoff Wall
Collection Drain
(Recommendation)
Pros
• Lower cost
• Ease of
construction
Cut Off Wall
Cons
• Maintenance of toe
drainage pipe
Pros
• No maintenance
of toe drainage
• Higher risk of piping
thru levee due to
clogging of toe drain
• Reduced risk of
piping thru levee
• Additional pumping
capacity required
(6,700 gpm)
Cons
• Higher cost
• Specialized
construction
• Concern that it
could raise
groundwater
levels and flood
basements
Building Design Branch
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11. Potential Pump Station Locations
Central SWPS
Location
Westside SWPS
Location
Eastside SWPS
Location
Building Design Branch
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12. Potential Pump Station Locations
Center of Levee
Western End
Property requirements
Property requirements
• Fairfax owned park property
• Adjacent commercial parcel is
ideal, but prohibitively costly
• Would occupy space otherwise
available for the excavated
ponding area or park recreation
area
Permanent Access
• From Liberty Dr. over raised road
through excavated ponding area
- Very exposed during storm
events, safety concern
Neighbor concerns / buffering
• In center of neighborhood park
recreation area
• Very visible from neighborhood
Drainage
Permanent Access
• Easy access off Fenwick Dr. or
new access road from Metroview
Pkwy.
Neighbor concerns / buffering
• Very close to homes at Fenwick
Dr.
Drainage
Eastern End
(Recommendation)
Property requirements
• Fairfax owned park property
Permanent Access
• New access road from Hunting
Creek Rd.
Neighbor concerns / buffering
• Far from residential properties in
Huntington Neighborhood
• Buffered by wooded area
• Divert all flow to Western end
• Backs up to apartment complex
recreation area
• Slightly smaller diversion channel
than Eastern option
Drainage
• Divert all flow to Eastern end
• Slightly larger diversion channel
than Western option
• Requires a third channel to
Cameron run with additional
wetlands impacts and
maintenance
Building Design Branch
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13. Stormwater Diversion
Building Design Branch
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14. Stormwater Diversion Options
Grass Lined Drainage Ditch
Concrete Drainage Ditch
Precast Concrete Box Culvert
• Erosion concern from high
flow velocities
• Not as wide due to steeper
side slopes (1:1 = 15’-20’ or
vertical = 10’)
• Fence to prevent access
• High construction cost for cast
in place
• Less maintenance than grass
lined
*Recommendation
• 30’ wide @ 2:1 side slopes
• Maintenance concerns and
mowing
• Standing water concerns due
to flat grades
• Lowest installation cost
• Limited access points – security
bars to prevent entry
• Buried – any potential standing
water is not exposed
• Precast construction – culvert
segments trucked to site
• Maintenance - confined space
entry
Building Design Branch
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15. Earthen Levee vs. Earthen Levee/Wall Combination
Earthen Levee
Earthen Levee / I-Wall Combination
(Recommendation)
Pros
• More natural aesthetic
Pros
• Reduced construction traffic
• Clear access to Cameron Run
• Lower cost
Cons
• Higher cost
• Smaller overall levee mass, width reduced by 17’
• Reduced backwater impacts
• Generates greater construction traffic
• Reduced impact to trees
• Greater overall levee mass, width varies
from 60 feet – 85 feet
Cons
• Maintenance of wall
• Access thru wall
Building Design Branch
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16. Earthen Levee/Wall Combination
Examples Architectural Facades
Building Design Branch
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17. Levee Cross Sections
Earthen Levee
Earthen Levee / I-Wall
Combination
Building Design Branch
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18. Earthen Levee/Wall Combination
Building Design Branch
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19. Earthen Levee/I-Wall Combination
Building Design Branch
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20. Accreditation
• Levee will be designed to meet FEMA accreditation
standards
• Fairfax County will submit an accreditation package
to FEMA for their consideration
Building Design Branch
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21. Questions
 Contact Information – Huntington Levee Project
 Phone #: 703-324-5800
 Email address: HuntingtonLevee@fairfaxcounty.gov
 Contact Information – Stormwater Questions
 Phone #: 703-324-5821
 Email address: SWPDmail@fairfaxcounty.gov
 Huntington Levee Website:
www.fairfaxcounty.gov/dpwes/huntingtonlevee
To request this document in an alternate format call 703-324-5800, TTY 711.
Building Design Branch
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