Four Mile Run
Restoration Project
Status Update
February 4, 2015
Background of Four Mile Run
 Watershed Area is 20 square miles.
 During the 1960s and 1970s, Four
Mile Run experience significant
flooding events as the watershed
became more urbanized.
 In 1974, Congress authorized the
United States Army Corps of
Engineers (USACE) to design and
construct a flood control channel
that would contain the increased
flows.
 Conditions of the federal project
were cost sharing and maintenance
agreements from Alexandria and
Arlington County.
Four Mile Run Master Plan
 In 2000, the City of Alexandria, Arlington
County and the Northern Virginia Regional
Commission (NRVC) began to explore the
stream’s water quality and recreation
potentials.
 Formal study was proposed to assess
modifications to the channel to improve water
quality without decreasing flood control
capacity. USACE partnered with team to
conduct a feasibility study on a restoration
plan.
 US Congressman Moran sought allocation
through EPA of $1M for development of the
Four Mile Run Master Plan, completed and
adopted by City and County in 2006. The
plan had significant community input and
support from both Arlington and Alexandria
residents.
Tidal Wetland Design
 In 2008, Arlington County and Alexandria received a Federal State and Tribal
Grant (STAG) matched with local funding for the design and construction of a
portion of the Master Plan. Combined, the jurisdictions have approximately $6
million. Grant funds had an initial deadline of September 2015 (later extended
to December, 2016).
 A “demonstration project” was selected to complete stream enhancements from
Mt. Vernon Ave to Route-1.
 Tidal Restoration design proceeded on project from 2008-2011. At that time, a
change in ACOE policies for flood channels necessitated a revised design.
Plan B Design for Four Mile Run
The inter-jurisdiction project team (ACG) developed an alternative design
to the Tidal Restoration Project, including bank and wetland restoration.
The new scope for the design was:
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Meets authorized capacity and minimizes flood risk
Includes no rise in water surface elevation
Improves pedestrian access to water
Improves stream habitat with living shorelines
Restore native plant habitat through landscape design
Continue as a joint effort between Arlington and Alexandria
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Plan B Overview
 Naturalize the banks along the corridor and improve access to the stream through
overlooks and terracing
 Minimize sediment transport by capturing it in accessible area (site 1)
 Replace rip-rap with vegetation and create Living Shorelines on Arlington side
(site 2)
 Establish historical tidal wetland condition in Four Mile Run Park (site 3)
Site 1
Site 2
Site 3
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Site 1 Summary
 Area near Mt. Vernon Bridge
 Create area for sediment deposition
 Build J-hook structure in the stream to direct flow
away from bank
J-Hook
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Site 2 Summary
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Area along Arlington side
Remove rip rap
Create living shoreline
Remove invasive plants
Replant with natives
Add viewing platform
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Site 2 Design Section
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Site 2 Plantings (plugs)
 Living shoreline: Arrow Arum, pickerelweed, broadleaf
arrowhead, river bulrush, common three-square
Pickerelweed
Arrow Arum
Three-square
 Upland meadow: Common milkweed, bee balm, grass
leaved goldenrod, black eyed susan
Bee balm
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Common Rush
Black eyed susan
Site 2 Seed Mix
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Schedule Sites 1/2
Bidding spring, 2015
Construction start July, 2015
No road or bike trail closures for project
May have short term bike trail stoppage with flaggers as
vehicles cross the trail
 Contractor will access site from Mt. Vernon parking lot or
S. Eads St.
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Coffer Dam
A coffer dam will be constructed
to allow work in the stream
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Site 3, Four Mile Run Wetland Restoration
Design
 Wetland Restoration
on Alexandria side
 Soil grading
 Invasive plant removal
 Native plantings
 New pervious surface
trail
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Site 3, Four Mile Run Wetland Restoration
Low Marsh Plantings
Yellow pond-lily
Nuphar advena
Annual wildrice
Zizania aquatica
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Arrow arum
Peltandra virginica
Site 3, Four Mile Run Wetland Restoration
High Marsh Plantings
Broadleaf arrowhead
Sagittaria latifolia
Softstem
Bulrush
Halberd-left rose mallow
Pickerelweed
Hibiscus laevis
Pontederia cordata
Schoenoplectus
tabernaemontani
Soft rush
Juncus effusus
Common three-square River bulrush
Southern blue flag Schoenoplectus pungens Bolboschoenus fluviatilis
Iris virginica
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Square stemmed
monkey flower
Mimulus ringens
Rice cutgrass
Leersia oryzoides
Site 3, Four Mile Run Wetland Restoration
Schedule
 Bidding winter 2014-2015
 On site project start: March 2015
Spring 2015
Summer 2015
Fall 2015
Winter 2015
Invasive Species
Eradication
Excavation/Earthwork
Plantings
Close-out/Clean-up
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Site 3, Four Mile Run Wetland Restoration
Construction Site and Detours
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WPCP Fence Enhancement
 The fence enhancement consists of over
800 linear feet of decorative additions
including brightly colored “widgets” that
reference the importance of
microorganisms in the Plant’s treatment
processes, shaped fence panels overlaid
on the existing fence to create a moiré
effect for trail users, and a bench to create
an inviting area for relaxation.
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Mock up fence panels and widgets, currently installed.
WPCP Fence Enhancement
 The enhancement project will serve as a
unifying element for the four projects
within this portion of the Four Mile Run
corridor: Parks’ Four Mile Run Master
Plan, the future pedestrian/cyclist
bridge, the planned stream restoration,
and the Plant’s landscaping.
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Birds eye view of enhancement area (in pink)
WPCP Fence Enhancement
 The project will
be installed and
completed Fall
2015.
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Rendering of fence enhancement with bench
Watermarks
Objectives
 Use existing infrastructure as bones for
design.
 Mark the ground at all outfalls,
highlighting the surrounding watershed’s
impact on 4MR.
 Use blue color as symbol of water to
raise awareness of the stream and its
water quality.
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Watermarks
 The symbolism of water and the
application of the color blue is essential
to the Watermark design.
 All Watermarks will be cast-in-place
concrete integrated with a blue pigment.
 23 Watermarks are proposed, 17 in
Arlington and 6 in Alexandria
 1 Watermark will be installed with the
construction of Plan B.
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Pedestrian Bridge
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Related Updates
 Berkeley Site plan
 Mt. Vernon Village Redevelopment
 Dominion – new line and potential movement of
terminal building
 Alexandria park improvements
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Questions?
http://www.novaregion.org/ search “Four Mile Run”