The Stormwater Maintenance Awareness Training course discusses vegetative practices.

1. A Fairfax County, VA, publication
Department of Public Works and Environmental Services
Working for You!
Stormwater Maintenance Awareness Training
For privately maintained stormwater management facilities
Maintenance and Stormwater Management Division (MSMD)
Winter 2018

2. Stormwater Maintenance Awareness Training
MSMD/DPWES
Course Schedule
AM session (includes two short breaks)
– History of SWM and regulations
– County inspection basics
– The inspection report and MAR
– Common SWM/BMP types
• Common maintenance items-General
– Common SWM/BMP types, deficiencies, and remedies
• Above Ground Facilities
12:00-1:00 PM Lunch
PM session (includes two short breaks)
– Common SWM/BMP types, deficiencies, and remedies
• Below Ground Facilities
• Vegetative Practices
– Closing remarks/questions
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NOTE: All pictures, unless noted, are the property of Fairfax County.

3. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Safety
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4. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
• Collects both piped and surface
runoff into a shallow landscaped
depression incorporating pollutant
removal mechanisms, filtration,
and infiltration characteristics
which mimic pre-development
conditions
– Infiltration is through a filter
bed of sand, soil and organic
material.
– Filtered runoff may be
returned to storm system via
an underdrain and/or
infiltrated into surroundings.
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Properly Functioning Example:

5. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
Properly Functioning Examples:
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6. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
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• Mulch layer
• Filter bed
• Inflow(s)
• Berm
• Ponding area
• Planned plantings
Optional Components
(Design Dependent)
• Energy dissipators
• Overflow structures
(majority of facilities)
• Observation wells or
underdrains
• Pretreatment (Linear BMP
implementation)
Mulch
Layer
Plantings
Energy
Dissipator
Inflow
Overflow Structure
BIO-RETENTION COMPONENTS

7. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
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Picture: VDEQ Stormwater Design Specification No. 9, Bioretention, Version 1.9, 3/1/11, Figure 9.5 “Typical Detail of Bioretention with Additional
Surface Ponding”
BIO-RETENTION COMPONENTS

8. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
8
Picture: VDEQ Stormwater Design Specification No. 9,
Bioretention, Version 1.9, 3/1/11, Figure 9.4 a “Typical Detail
of Bioretention Basin Level 1 Design” & Figure 9.4 b “Typical
Detail of Bioretention Basin Level 2 Design”
BIO-RETENTION COMPONENTS

9. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
Routine Deficiencies Observed
Overflow/Control Structures
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Overgrown Vegetation Spalling/deterioration
Sediment/debris Erosion around
structure

10. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
Ponding Area, including Mulch Layer and Vegetation
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Missing, dead, & overgrown vegetation
are common items

11. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
Ponding Area, including Mulch Layer and Vegetation
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Sediment and debris
Other Common Issues Include:
• Inadequate mulch layer (<2-3”)
• Over-mulching (mounding)
• Inadequate ponding depth
• Standing water after 48 hours
Check approved site plans for details
Exposed filter fabric

12. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
Berm
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Erosion and trenching
Other common items:
• Bare spots
• Missing/improperly constructed berm
Animal hole

13. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
• Common Remedies
– Remove all flow blockages as well as any additional trash, debris, and
accumulated sediment
– Repair/replace any damaged/missing components
• Components vary by facility type and design, and they can range
from parts to structural to environmental materials (see prior noted
examples)
– Check plans for specific facility requirements
• Missing or inadequate mulch levels are common for this type of
facility
– Refer back to approved plan
– Plant types/sizes are important if trees are being used toward meeting
your tree canopy requirements
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14. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Bio-Retention (BR)
• Common Remedies
– Standing water after 48 hours:
• Underdrain may need to be flushed and re-checked
– Rebuild/stabilize any areas with erosion and bare spots:
– Cut back overgrown vegetation around facility structures to facilitate
access and proper function
• Replace/replant any dead, dying, or missing vegetation per
approved site plan
• Remove any non-spec vegetation, especially if it impacts the health
and function of the facility, as designed
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15. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Tree Filters (TF)
• Ultra-urban bioretention in a
prefabricated box*, always tied
into stormwater infrastructure via
an underdrain
– Typically implemented in large
areas of imperviousness
(parking lots, schools, etc.)
– Plant provides biological
pollutant and nutrient uptake
– Sometimes called Tree Box
Filters
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Properly Functioning Example:
* Note: While the Filterra TF (via Contech) is used here as a convenient example of commonly available/utilized
technology, Fairfax County does not endorse any specific tree filter product over another.

16. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Tree Filters (TF)
TREE FILTER COMPONENTS
• Plant (shrub or tree)
• Mulch
• Filter media
• Underdrain
• Throat
• Overflow structure
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Overflow Structure
PlantTree
Frame
and Grate

17. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Tree Filters (TF)
TREE FILTER COMPONENTS (Typical Tree Filter Section View-Filterra 2007)
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www.conteches.com
Fairfax County BMP Fact Sheet

18. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Tree Filters (TF)
Routine Deficiencies Observed
Throat Opening/Mulch Layer
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Common Items:
• Trash, debris, and sediment
accumulation, usually at the throat
• Inadequate mulch layer
• Missing surge stone at throat
• Spalling and deterioration

19. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Tree Filters (TF)
Plants/Vegetation
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Dead Vegetation
Missing Vegetation Damaged Vegetation
Overgrown/Crowded

20. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Tree Filters (TF)
Outfall/Overflow Structures
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OTHER COMMON ITEMS:
• Blockages
• Sediment/debris
• Separation/misaligned
joints
Spalling and concrete deterioration

21. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Tree Filters (TF)
• Common Remedies
– Remove all flow blockages as well as any additional trash, debris, and
accumulated sediment
– Rebuild/stabilize any areas with erosion and bare spots
– Repair/replace any damaged/missing components
• Components vary by facility type and design, and they can range
from parts to structural to environmental materials (see prior noted
examples)
– Check approved site plans for specific facility requirements
• Missing or not to spec media and mulch levels are common for this
type of facility
• Missing pre-treatment devices, per approved plans
21

22. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Tree Filters (TF)
• Common Remedies
– Standing water after 48 hours:
• Underdrain may need to be flushed and re-checked
– Cut back overgrown vegetation around facility structures to facilitate
access and proper function
• Replace/replant any dead, dying, or missing vegetation per
approved site plan
• Remove any non-spec vegetation, especially if it impacts the health
and function of the facility, as designed
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23. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Green Roof (GR)
• Captures, temporarily stores, &
reduces runoff, while also reducing
pollutant loads through biological
nutrient uptake
– Extensive Roof systems have
shallow soil media (2-6”), with
drought tolerant plants such as
sedums, and are primarily
functional
– Intensive Roof Systems have
deeper soil media (6-12”),
more extensive plantings, and
also act as public green spaces
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Properly Functioning Examples:
Intensive Roof System
Intensive Roof System
Extensive Roof System
INTENSIVE ROOF SYSTEM

24. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Green Roof (GR)
– Deck layer
– Waterproofing layer
– Insulation layer
– Root barrier
– Drainage layer and drainage
system
– Root-permeable filter fabric
– Growing media
– Plant cover
– Roof drains
– Emergency overflow
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VDEQ Stormwater Design Specification No. 5, Vegetated Roof, Version 2.3, 3/1/11,
Figure 5.2 “Typical Section-Extensive Vegetated Roof (Source: Northern VA Regional
Commission)”
GREEN ROOF COMPONENTS

25. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Green Roof (GR)
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Aluminum
curb, filter
fabric, &
drainage layer
(VDEQ Stormwater
Design Specification No.
5 Vegetated Roof,
Version 2.3, 3/1/11,
Figure 5.1 “Photos of
Vegetated Roof Cross
Sections (Source: B.
Hunt, NCSU)
Roof drain Rooftop access (hatch,
door, or ladder)
Roof drains and scuppers help to drain off any excess
water to avoid accumulation
Multiple downspouts can drain to the GR (from other
roof sections)
GREEN ROOF COMPONENTS

26. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Green Roof (GR)
Routine Deficiencies Observed
– Dead/dying vegetation
– Invasive species
– Weeds
– Waterproof membrane
• Leaks
• Cracks
– Clogged roof drains or scuppers
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27. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Green Roof (GR)
• Common Remedies
– Remove all flow blockages as well as any additional trash, debris, and
accumulated sediment
– Repair/replace any damaged/missing components
• Components vary by facility type and design, and they can range
from parts to structural to environmental materials (see prior noted
examples)
– Check plans for specific facility requirements
– Rebuild/stabilize any areas with erosion and bare spots
– Cut back overgrown vegetation to facilitate proper function
• Replace/replant any dead, dying, or missing vegetation per
approved site plan
• Remove any non-spec vegetation, especially if it impacts the health
and function of the facility, as designed
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28. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Vegetative Swales (VS)
• Similar to BR in form and function, though typically
configured as a shallow linear channel
– Primarily stormwater conveyance
– Pollutant removal provided via temporary storage/filtration
– VS typically lined with turf or other non-turf vegetation to protect
against bank shear stress due
to greater runoff velocities
• Check site plans for proper
vegetation type
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29. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Vegetative Swales (VS)
• Vegetated banks
• Filter media
• Inflows
• Ponding area
• Overflow structure
Optional Components
(Design Dependent)
• Check dams
• Pretreatment
• Planned plantings
• Underdrains
• Observation wells
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Overflow Structure
Observation
Well
Vegetated
Berm
VEGETATIVE SWALE COMPONENTS

30. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Vegetative Swales (VS)
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Picture: VDEQ Stormwater Design Specification No. 10, Dry Swales, Version 1.9, 3/1/11, Figure 10.2 “Typical Detail s for Level 1 and 2 Dry Swales”
VEGETATIVE SWALE COMPONENTS

31. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Vegetative Swales (VS)
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VEGETATIVE SWALE COMPONENTS

32. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Vegetative Swales (VS)
Routine Deficiencies Observed
Check Dams and Overflow/Control Structure
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Undermining/erosion Spalling & deterioration
Sediment and debris
Overgrown vegetation
Internal blockages
are also common
(not shown)

33. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Vegetative Swales (VS)
Vegetated Banks/Ponding Area/Vegetation
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Common Items (Clockwise
from TOP LEFT):
• Overgrown vegetation
(see plans, amount varies)
• Clogging/poor drainage
(ponding water after 48hrs
of dry weather)
• Sediment accumulation
(plant growth in gravel
often a sign of sediment)
• Erosion, bare spots
• (Not shown) Trash & debris
Upper-right photo is from VDEQ Stormwater
Design Specification No. 3, “Grass Channels”,
Version 1.9, 3/1/11

34. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Vegetative Swales (VS)
Cleanouts/Observation Wells
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LEFT: Broken/damaged RIGHT: Trash/debris
Other Common Items:
• Unable to locate (possibly overgrown vegetation)
• Cap stuck, broken, or missing

35. Stormwater Maintenance Awareness Training
MSMD/DPWES
Vegetative Practices-Vegetative Swales (VS)
• Common Remedies
– Remove all flow blockages as well as any additional trash, debris, and
accumulated sediment
– Repair/replace any damaged/missing components
• Components vary by facility type and design, and they can range
from parts to structural to environmental materials (see prior noted
examples)
– Check approved site plans for specific facility requirements
– Rebuild/stabilize any areas with erosion and bare spots:
– Cut back overgrown vegetation around facility structures to facilitate
access and proper function
• Replace/replant any dead, dying, or missing vegetation per
approved site plan
• Mow per plan maintenance guidelines
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36. Stormwater Maintenance Awareness Training
MSMD/DPWES
Additional Resources
• Fairfax County
– Public Facilities Manual
(https://www.fairfaxcounty.gov/landdevelopment/public-facilities-manual)
– Stormwater Management Website
(http://www.fairfaxcounty.gov/publicworks/stormwater/)
– Stormwater Best Management Practices Fact Sheets
(https://www.fairfaxcounty.gov/publicworks/stormwater/facility-fact-sheets)
• Virginia Department of Environmental Quality
– Stormwater Management Website
(http://www.deq.virginia.gov/Programs/Water/StormwaterManagement.aspx)
– Virginia Stormwater BMP Clearinghouse
(http://www.vwrrc.vt.edu/swc/)
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37. Stormwater Maintenance Awareness Training
MSMD/DPWES
Additional Resources
• Virginia Department of Transportation
– N. VA Fairfax & Arlington Counties Permits
(http://www.vdot.virginia.gov/business/fairfax-permits-main.asp)
– Manuals Guides and Informational Instructions
(http://www.virginiadot.org/business/manuals-default.asp)
• Includes BMP Design Manual, Drainage Manual, ROW Manual, etc.
– Virginia Work Area Protection Manual: Temporary Traffic
Control
(http://www.vdot.virginia.gov/business/resources/wztc/Virginia_WAPM_2011_web.pdf)
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38. Additional Information
For additional information, please contact
www.fairfaxcounty.gov/dpwes
MSMD/DPWES 38
Department of Public Works and Environmental Services
Maintenance and Stormwater Management Division
703-877-2800, TTY 711
Stormwater Maintenance Awareness Training
www.fairfaxcounty.gov/publicworks