The project provides approximately 3,600 linear feet (LF) of new stormwater conveyance; and 2,000 LF of new sanitary main and service connections for 23 homes; and fully milled and repaved Hayfield Road, Telegraph Road intersection and Bridgewater Court. Presented at a Hayfield Citizens Association Meeting on September 16, 2020.

1. A Fairfax County, VA, publication
Department of Public Works and Environmental Services
Working for You!
September 16, 2020
Hayfield Road
Pipe
Conveyance
Project
Hayfield Citizens Association Meeting –
September 16, 2020

2. 2
Hayfield Road Pipe Conveyance Project
Tonight’s Agenda
WATERSHED PROJECTS IMPLEMENTATION BRANCH – SOUTH, STORMWATER PLANNING DIVISION
Project summary,
review remaining work,
warranties,
& recognition

3. 3
 The project provides:
o Approximately 3,600 LF of new stormwater conveyance.
• This design will carry the 100-year storm event.
• Improves/removes the flood risk for at least 45 homes that sit over/near the original 72” pipe. This
includes the homes on the west side of Hayfield Road & the properties adjoining these parcels’ rear
property boundaries.
o Approximately 2,000 LF of new sanitary main & service
later connections for 23 homes.
o Contract allowed 365 days. Project completed
almost 2 months early.
o Fully milled & repaved Hayfield Road, Telegraph Road
intersection, & Bridgewater Court
 Correct the outfall condition
o Designed outfall elevation is too low for the surrounding grade & water ponds
• Design revisions will provide excavated/lowered drainage swales around the central tree save area
• A stone sill will be installed to help protect the tree save area from flows & direct stormwater
discharge to the new swales
• Native vegetation plantings will be used to stabilize the swales & help manage flow velocities
• Schedule is to complete this fall
WATERSHED PROJECTS IMPLEMENTATION BRANCH – SOUTH, STORMWATER PLANNING DIVISION
Hayfield Road Pipe Conveyance Project
OVERVIEW

4.  Plantings
o Hayfield Road median: Replace trees removed during project with same species with one exception
• These include Red maple (Acer rubrum), American holly (Ilex opaca), and Red bud (Cercis canadensis).
• At the direction of the HCA Board, the Silver maple will be replaced with Red maple.
• At the original median planting, the landscaper installed Silver maples in error.
• Several additional trees will be planted to replace a few in severe decline & to fill an open
area near Telegraph Road.
• Scheduled for the fall 2020 planting window after the outfall regrading is complete.
o Median flowers: To the extent that construction removed/damaged any of the flowers (Ice Follies and King Alfred
daffodils) planted on the ends of medians, these will be replaced. Timing is spring 2021 after blooming.
o Outfall: Remove & replace the plantings installed in the fall 2019
• The landscape subcontractor did not provide only native plantings.
• Contrary to the design requirements, cultivars were installed.
• Cost to be borne by the primary/subcontractor.
• Replacements scheduled to be completed this fall.
4WATERSHED PROJECTS IMPLEMENTATION BRANCH – SOUTH, STORMWATER PLANNING DIVISION
Hayfield Road Pipe Conveyance Project
OVERVIEW
o Following all the heavy construction traffic & deliveries, the Swim Club
driveway & access is replaced/restored.
o Hayfield Park was not used for storage & staging. So, no restoration work
required.

5. 5
 Project warranty
o Hardscape & infrastructure (pipe, box culvert, curb & gutter, etc.) carry a 1-year warranty
from the date of Substantial Completion beginning August 21, 2020.
o Plantings carry a 1-year warranty from the date the last plant is installed.
• Woodies & plugs: 1-year from the date the final plant is installed fall 2020.
• Ephemerals/flowers: 1-year from the date the damaged/removed bulbs are planted
spring 2021.
Hayfield Road Pipe Conveyance Project
WATERSHED PROJECTS IMPLEMENTATION BRANCH – SOUTH, STORMWATER PLANNING DIVISION
REMAINING WORK
(Plantings cont’d)
o Additional outfall plantings
• With the outfall regrading complete, the area inside the fish-scale weirs will be planted with native
wetland plugs to stabilize the soil & manage discharge velocities.
• Side slopes of outfall area will also receive additional native trees & shrubs
• Examples: River birch (Betula nigra), Hackberry (Celtis occindetalis), Paw paw (Asimina triloba),
Sweetbay magnolia (Magnolia virginiana), Silky dogwood (Cornus amomum), Soft rush (Juncus
effuses), Wool grass (Scirpus cuperinus)
 Unintended benefit is improved water quality discharged into Dogue
Creek/Huntley Meadows Park due to the combination of all plantings in &
around the outfall area & the level spreaders.

6. 6
Outfall level spreaders – pictures & functions
Hayfield Road Pipe Conveyance Project
WATERSHED PROJECTS IMPLEMENTATION BRANCH – SOUTH, STORMWATER PLANNING DIVISION
Coir logs & native shrub plantings
on each side. The coir logs &
shrubs form an impediment to
flow slowing velocity & forcing
flow into shallow sheet flow.
Graded level spreader surrounded by new plantings &
existing forest. Grading provides a low spot for water to
collect, slow, & spread out until it then flows over the
downstream side of the graded area.
Outfall area below plunge pool – fish-scale weirs under construction.
Wood forms will be filled with concrete & native wetland plugs will
be planted inside the curved cells. Discharged water will flow over
the concrete being slowed & spread out.
Level spreaders serve to slow water flow
velocity, force the water to spread out in
shallow sheet flow, & prevent
concentrated flow from forming.
Concentrated flows pose the biggest
erosion risk.
The extensive tree, shrub, & plug plantings
also help slow flow velocity, stabilize the
soil, & uptake & use the water & any
contaminants (think primarily nitrogen &
phosphorus) as growth nutrients. This
plant uptake removes contaminants from
the discharge & thereby polishes &
improves the water quality leaving the new
conveyance system.

7. 7
WATERSHED PROJECTS IMPLEMENTATION BRANCH – SOUTH, STORMWATER PLANNING DIVISION
Other Matters
Hayfield Road Pipe Conveyance Project
Please join us for a ribbon cutting ceremony to recognize
completing the project.
Where: Hayfield Swim Club parking lot
When: Thursday, October 1
Time: 4:45 pm start
Rain date: Thursday, October 8 – other details remain the same
Board Chairman Jeff McKay,
Lee District Supervisor Rodney Lusk, &
County Executive Bryan Hill
are scheduled to join us.

8. Contact Information
During the warranty period, Brendan Schillo & I
remain the project managers
8WATERSHED PROJECTS IMPLEMENTATION BRANCH – SOUTH, STORMWATER PLANNING DIVISION
Dave Anglin, Section Chief
dave.anglin@fairfaxcounty.gov
703-324-5500
www.fairfaxcounty.gov/dpwes
Hayfield Road Pipe Conveyance Project
Brendan Schillo, PE, Project Engineer
703-659-7048
Brendan.schillo@fairfaxcounty.gov