20181638 Ver 2_Appdx G BMP Control Standards_20190208

m �m * W11 X
mountain
'"Tr
PIPELI
MVP Southgate Project
Appendix G
BMP Control Standards

Practice Standards and Specifications
Definition A temporary ridge or excavated channel or combination ridge and channel
constructed across sloping land on a predetermined grade.
Purpose To protect work areas from upslope runoff, and to divert sediment -laden water
to appropriate traps or stable outlets.
Conditions Where This practice applies to construction areas where runoff can be diverted and
Practice Applies disposed of properly to control erosion, sedimentation, or flood damage.
pp Specific locations and conditions include:
• above disturbed existing slopes, and above cut or fill slopes to prevent
runoff over the slope;
• across unprotected slopes, as slope breaks, to reduce slope length;
• below slopes to divert excess runoff to stabilized outlets;
• where needed to divert sediment -laden water to sediment traps;
• at or near the perimeter of the construction area to keep sediment from
leaving the site; and
• above disturbed areas before stabilization to prevent erosion, and maintain
acceptable working conditions.
• Temporary diversions may also serve as sediment traps when the site has
been overexcavated on a flat grade; they may also be used in conjunction
with a sediment fence.
Planning It is important that diversions are properly designed, constructed and
Considerations maintained since they concentrate water flow and increase erosion potential
(Figure 6.20a). Particular care must be taken in planning diversion grades.
Too much slope can result in erosive velocity in the diversion channel or at the
outlet. A change of slope from steeper grade to flatter may cause deposition to
occur. The deposition reduces carrying capacity, and may cause overtopping
and failure. Frequent inspection and timely maintenance are essential to the
proper functioning of diversions.
Sufficient area must be available to construct and properly maintain diversions.
It is usually less costly to excavate a channel and form a ridge or dike on the
Compacted soil 2'
I< min I
_ 1$ min
i -=fli°II ®jll ®61�111° ..III µ1l6 -i...�
6' typical
6.20.1

v
downhill side with the spoil than to build diversions by other methods. Where
space is limited, it may be necessary to build the ridge by hauling in diking
material, or using a silt fence to divert the flow. Use gravel to form the
diversion dike when vehicles must cross frequently (Figure 6.20b).
r�+.-t�.�r,•s.*� 1.is�� i•/��rii��`4.rr'I'i�':wirt *.
j ��+ w}'� • �.�s •rre-.• ♦ •• .� rr• ��.►M�•�,►,,.,� moi.
1111 1i trr� LMS
f9'typicalt....
Plan temporary diversions to function 1 year or more, or they may be
constructed anew at the end of each day's grading operation to protect new fill.
Diversions that are to serve longer than 30 working days should be seeded and
mulched as soon as they are constructed to preserve dike height and reduce
maintenance.
Where design velocities exceed 2 ft/sec, a channel liner is usually necessary to
prevent erosion (Table 8.05a, Appendix 8.05).
Temporary diversions may serve as in-place sediment traps if overexcavated 1
to 2 feet and placed on a nearly flat grade. The dike serves to divert water as
the stage increases. A combination silt fence and channel in which fill from
the channel is used to stabilize the fence can trap sediment and divert runoff
simultaneously.
Wherever feasible, build and stabilize diversions and outlets before initiating
other land -disturbing activities.
Design Criteria Drainage area -5 acres or less.
Capacity—peak runoff from 10 -year storm.
Velocity—See Table 8.05a, Permissible Velocities for Erosion Protection,
Appendix 8.05.
Ridge design— side slope
top width
freeboard
settlement
6.20.2
2:1 or flatter
3: 1 or flatter at points where cross
2 ft minimum
0.3 ft minimum
10% of total fill height minimum

Practice Standards and Specifications
Channel design— shape: parabolic, trapezoidal, or V-shaped
side slope: 2:1 or flatter
3:1 or flatter where vehicles cross
Grades— Either a uniform or a gradually increasing grade is preferred.
Sudden decreases in grade accumulate sediment and should be expected to
cause overtopping. A large increase in grade may erode.
Outlet—Design the outlet to accept flow from the diversion plus any other
contributing areas. Divert sediment -laden runoff and release through a
sediment -trapping device (Practice 6.60, Temporary Sediment Trap and
Practice 6.6 1, Sediment Basin). Flow from undisturbed areas canbe dispersed
by a level spreader (Practice 6.40, Level Spreader).
Small diversions—Where the diversion channel grade is between 0.2 and
3%, a permanent vegetative cover is required. A parabolic channel and ridge
1.5 feet deep and 12 feet wide may be used for diversions with flows up to 5
cfs. This depth does not include freeboard or settlement. Side slopes should
be 3:1 or flatter, and the top of the dike must be at least 2 feet wide.
Construction 1. Remove and properly dispose of all trees, brush, stumps, and other
Specifications objectionable material.
2. Ensure that the minimum constructed cross section meets all design
requirements.
3. Ensure that the top of the dike is not lower at any point than the design
elevation plus the specified settlement.
4. Provide sufficient room around diversions to permit machine regrading and
cleanout.
5. Vegetate the ridge immediately after construction, unless it will remain in
place less than 30 working days.
Maintenance Inspect temporary diversions once a week and after every rainfall. Immediately
remove sediment from the flow area and repair the diversion ridge. Carefully
check outlets and make timely repairs as needed. When the area protected is
permanently stabilized, remove the ridge and the channel to blend with the
natural ground level and appropriately stabilize it.
References Surface Stabilization
6. 10, Temporary Seeding
6. 11, Permanent Seeding
6.14, Mulching
Outlet Protection
6.40, Level Spreader
6.41, Outlet Stabilization Structure
6.20.3

v
6.20.4
Sediment Traps and Barriers
6.60, Temporary Sediment Trap
6.6 1, Sediment Basin
Appendices
8.03, Estimating Runoff
8.05, Design of Stable Channels and Diversions

Practice Standards and Specifications
Definition A dike or dike and channel constructed along the perimeter of a disturbed
construction area.
Purpose To prevent storm runoff from entering the work area, or to prevent sediment -
laden runoff from leaving the construction site.
Conditions Where Diversion dikes may be located at the upslope side of a construction site to
Practice Applies prevent surface runoff from entering the disturbed area or at the downslope
side of the work area to divert sediment -laden runoff to on-site sediment traps
or basins. Diversion dikes do not usually encircle the entire area.
The upslope dike can improve working conditions at the construction site and
prevent erosion. The downslope dike assures that sediment -laden runoff will
not leave the site without treatment.
Planning A diversion dike is a special application of a temporary or permanent
Considerations version. It differs from other diversions in that the location and grade are
usually fixed, and the cross section and stabilization requirements are based on
the existing grade of the work boundary. Hence, the design cross section may
vary significantly throughout the length. Give special care to avoid erosive
velocities in steep areas. Identify areas where sedimentation will occur since
they are often subject to overtopping.
Immediately vegetate diversion dikes after construction, but make sure channel
flow area is stabilized during construction. Exercise caution in diverting flow
to be certain that the diverted water is released through a stable outlet and
that the flow will not cause flood damage. Diversion dikes may be either
temporary or permanent depending on site conditions (Figure 6.22a).
`!�'M�+wa. Mi�� �., "iia.. ,a�, ay,�a.n� 'A,aa .a „t,i` ti a+ •� ,.ask iNl •,iii
A.. w• 1� 1. Oi*. � � la
6.22.1

v
Design Criteria Drainage area -5 acres or less.
Capacity—consistent with the hazard involved and design life and with a 10
year peak runoff minimum.
Velocity—See Table 8.05a, Appendix 8.05.
Dike design— side slope: 2:1 or flatter
3:1 or flatter where vehicles must cross
width: 2.0 feet minimum top width
height: 1.5 feet minimum
freeboard: 0.5 feet minimum
settlement: 10% of total fill height minimum
Channel design— shape
side slope
stabilization:
parabolic, trapezoidal, or V-shaped
2:1 or flatter
3:1 or flatter where vehicles must cross
based on velocity by reaches
Grade—Dependent on site topography. Channel should have positive grade.
Outlet—Divert sediment -laden water into a temporary sediment trap or
sediment basin. Runoff from undisturbed areas should empty into an outlet
protection device such as a level spreader or riprap outlet structure unless well
stabilized natural outlets exist.
Construction 1. Remove and properly dispose of all trees, brush, stumps, and other
Specifications
objectionable material. Fill and compact, to natural ground level or above, all
ditches and gullies that will be crossed by machinery.
2. Disk the base of the dike before placing fill.
3. Ensure that the constructed cross section meets all design requirements.
4. Compact the dike by tracking with construction equipment.
5. Ensure that the top of the dike is not lower at any point than the design
elevation plus the specified settlement after it has been compacted.
6. Leave sufficient area along the dike to permit machine re -grading and
cleanout.
7. Immediately seed and mulch the dike after its construction, and stabilize the
flow portion in accordance with design requirements.
Maintenance Inspect diversion dikes once a week and after every rainfall. Immediately
remove sediment from the flow area and repair the dike.
Check outlets, and make timely repairs as needed to avoid gully formation.
When the area above the temporary diversion dike is permanently stabilized,
remove the dike, and fill and stabilize the channel to blend with the natural
surface.
6.22.2

Practice Standards and Specifications
References Surface Stabilization
6.10, Temporary Seeding
6. 11, Permanent Seeding
6.14, Mulching
Outlet Protection
6.40, Level Spreader
6.41, Outlet Stabilization Structure
Sediment Traps and Barriers
6.60, Temporary Sediment Trap
6.6 1, Sediment Basin
Appendix
8.05, Design of Stable Channels and Diversions
6.22.3

Practice Standards and Specifications
Definition A ridge or ridge and channel constructed diagonally across a sloping road or
utility right-of-way that is subject to erosion.
Purpose To limit the accumulation of erosive volumes of water by diverting surface
runoff at predesigned intervals.
Conditions Where Where runoff protection is needed to prevent erosion on sloping access rights -
Practice Applies of -way or other long, narrow sloping areas generally less than 100 feet in
width.
Planning Construction of access roads, power lines, pipelines, and other similar
Considerations installations often requires clearing long narrow rights-of-way over sloping
terrain (Figure 6.23a). Disturbance and compaction promotes gully formation
in these cleared strips by increasing the volume and velocity of runoff.
Gully formation may be especially severe in tire tracks and ruts. To prevent
gullying, runoff can often be diverted across the width of the right-of-way
to undisturbed areas by using small predesigned diversions. Give special
consideration to each individual outlet area, as well as to the cumulative effect
of added diversions. Use gravel to stabilize the diversion where significant
vehicular traffic is anticipated.
Design Criteria Height -18 -inch minimum measured from the channel bottom to the ridge
top.
Table 6.23a
Spacing of Water Bars on
Right -of -Way Less than
100 ft Wide
Construction
Specifications
Side slope -2:1 or flatter
3:1 or flatter where vehicles cross
Base width of ridge -6 feet minimum (Figure 6.23b).
Spacing of water bars is shown in Table 6.23a:
Slope (%)
Spacing (Ft)
<5
125
5 to 10
100
10 to 20
75
20 to 35
50
>35
25
Grade and angle—A crossing angle should be selected to provide a positive
grade not to exceed 2%
Outlet—Diversions should have stable outlets, either natural or constructed.
Site spacing may need to be adjusted for field conditions to use the most
suitable areas for water disposal.
1. Install the diversion as soon as the right-of-way has been cleared and
graded.
2. Disk the base for the constructed ridge before placing fill.
Rev. 12/93 6.23.1

3. Track the ridge to compact it to the design cross section.
4. Locate the outlet on an undisturbed area. Adjust field spacing of the
diversion to use the most stable outlet areas. When natural areas are not
deemed satisfactory, provide outlet protection (Practices 6.40, Level Spreader,
and 6.4 1, Outlet Stabilization Structure).
5. Immediately seed and mulch the portions of the diversions not subject to
construction traffic. Stabilize with gravel areas to be crossed by vehicles.
6.23.2
< • .° r1 Vea r.r.let
`t•leet 1�xlt:y`•yi ,
1
n�•S .,
lu��e�.�w .�4ai��kq�1\ •y.,,<•r�t
m llll 1... - ,
m i y�I� t '�• '' +le
Bl.la'e.e Y`� ..etre.. , .. •'b0.ete•
'•tYl p�y^�j�
t y6r.. rl u�agl'nA?(,
rty� 0\1Vit illi\uJ�e411e41 ��y f!
tali%i{q
a41it l Ota �jilJ ' `bi�Y�.� tl�llY 11ky t
tskN 41 �jtlr '^71a r
y y
iqk �lili!!
ti:11u�{�y tui t t n 4t .,:r
t I„. ,srr I �
.,it
M AJatu�lie.
C' It Idi 4a't� dill 1' �4l slrli�+��'diih9a �`i. ��,t� {
,•rh)t,l ��
i
,l\t
jItf\ 1.,
�;IIYj! { tt;iljli�ii)��It�;i1.1.�Itlll�lta �,a , hlCe° Y�,
r a..e_t• .
>.t.e
`. Ali)
n. ,.`Mt`s<�t'�
.14111d10#1pinN
?ll►NlIiytln.
'r6+,e;�.t,... ll 1t
II,J1
,
4
✓'fit �j�laY`
� .i'q
tX1110_—
�,,,. �h IUI„
� � i'lIII Ilh{� 11
�
67
�e 0d���
U 6� o,
ll,it ti111, rJ�„� .
3. Track the ridge to compact it to the design cross section.
4. Locate the outlet on an undisturbed area. Adjust field spacing of the
diversion to use the most stable outlet areas. When natural areas are not
deemed satisfactory, provide outlet protection (Practices 6.40, Level Spreader,
and 6.4 1, Outlet Stabilization Structure).
5. Immediately seed and mulch the portions of the diversions not subject to
construction traffic. Stabilize with gravel areas to be crossed by vehicles.
6.23.2

Practice Standards and Specifications
Maintenance Periodically inspect right-of-way diversions for wear and after every heavy
rainfall for erosion damage. Immediately remove sediment from the flow
area, and repair the dike. Check outlet areas, and make timely repairs as
needed. When permanent road drainage is established and the area above
the temporary right-of-way diversions is permanently stabilized, remove the
dike, and fill the channel to blend with the natural ground, and appropriately
stabilize the disturbed area.
References outlet Protection
6.40, Level Spreader
6.41, Outlet Stabilization Structure
Appendix
8.03, Estimating Runoff
6.23.3

6.24
Practice Standards and Specifications
Definition Controlling runoff and erosion in riparian areas by establishing temporary annual
and perennial native vegetative cover.
Purpose To protect riparian areas from erosion and decrease sediment yield in adjacent
streams using temporary annual vegetation as an immediate cover and establish
perennial native herbaceous vegetation.
Conditions Where Disturbed riparian areas between streams and uplands where permanent
Practice Applies herbaceous vegetation is needed to stabilize the soil and provide long-term
protection.
Planning Native vegetation species are defined as plant species that naturally occur in the
Considerations region in which they evolved. These plants are adapted to local soil types and
climatic variations and generally require little to no maintenance. Many of the
species have evolved deep, extensive root structures that help stabilize soils and
reduce erosive forces of rainfall and overland stream flow. Native species
possess certain characteristics that allow them not only to survive, but also to
thrive under local conditions. Further, naturally occurring plant communities
provide optimal habitat for terrestrial and aquatic fauna. Other agency permits
(i.e., ACOE 404 and DWQ 40 1) may specify further conditions for establishment
of native woody vegetation and limits on use of mechanical equipment.
Seeding a mixture of perennial native grasses, rushes, and sedges is a common
way to establish permanent ground cover within riparian areas. Both labor and
material costs are lower than installation of propagated plants, though some sites
may require installation of established vegetation due to site limitations.
Selecting a seed mixture with different species having complementary
characteristics will allow vegetation to fill select niches within the varying
riparian area and respond to different environmental conditions.
Despite the advantages, several disadvantages of seeding riparian areas with
native seed may include:
• Potential for erosion or washout during the establishment stage;
• Longer time for germination and establishment;
• Seasonal limitation on suitable seeding dates;
• Specificity of species at each site;
• Need for water and appropriate temperatures during germination and
early growth; and
• Need for invasive plant/competition control.
A temporary, non-invasive, and non-competitive annual grass species should be
incorporated with the native seeding. This will provide an immediate cover over
the site that serves to:
• Prevent bare soil exposure and hold soil in place; and
• Provide a nurse crop for native seeds while they become established.
Rev. 5/13 6.24.1

Practice Standards and Specifications
Temporary annual species should be planted at a low density so they do not
suppress growth of permanent species.
Successful plant establishment can be maximized through good planning,
knowledge of soil characteristics, selections of suitable plant species for each
site, proper seedbed preparation, and timely planting and maintenance.
Selecting Plant Permanent seed species within the seed mixture should be selected based on
Materials natural occurrence of each species in the project site area. Climate, soils, and
topography are major factors affecting the suitability of plants for a particular
site and these factors vary widely across North Carolina, with the most
significant contrasts occurring among the three major physiographic regions of
the state — Mountains, Piedmont, and Coastal Plain. Even within the riparian
area, there may be need for different species depending on site conditions (i.e.
dry sandy alluvial floodplains with wet pockets). Therefore, thoughtful planning
is required when selecting species for individual sites in order to maximize
successful vegetation establishment.
Seeds adapted to North Carolina should be purchased from a reputable seed
grower and should be certified. Do not accept seed containing "prohibited"
noxious weed seed. For successful broadcast seeding, seeds should be cleaned.
If warm season grasses with "fluffy" seeds are used, a specialized warm season
grass drill should be employed. Cultivars should be selected based on adaptation
to site region. Stratification, either naturally or artificially, is required for most
native seed species to ensure proper germination.
Table 6.24a provides suitable temporary seed species with recommended
application rates and optimal planting dates. Temporary annual seed selection
should be based on season of project installation. A single species selection for
temporary cover is acceptable. In some cases where seasons overlap, a mixture
of two or more temporary species may be necessary; however, application rates
should not exceed the total recommended rate per acre. Temporary seed should
be mixed and applied simultaneously with the permanent seed mix if optimal
planting dates allow.
i apie O.L4a i emnorary ;!oeeaing necommenaations
Common Name
Scientific Name
Rate per
Acre
Optimal Planting Dates
Mountains
Piedmont
Coastal Plain
Rye grain
Secale cereale
30 lbs
Aug. 15
- May 15
Aug. 15 - May 1
Aug. 15
-Apr. 15
Wheat
Triticum aestivum
30 lbs
Aug. 15
- May 15
Aug. 15 - May 1
Aug. 15
-Apr. 15
German millet
Setaria italica
10 lbs
May 15 -
Aug. 15
May 1 -Aug. 15
Apr. 15 -
Aug. 15
Browntop millet
Urochloa ramosa
10 lbs
May 15 -
Aug. 15
May 1 -Aug. 15
Apr. 15 -
Aug. 15
Tables 6.24b -6.24d provide selections of native permanent seeds based on
physiographic regions. Included in these tables are species, cultivars, appropriate
percentage rates of mixture, and optimal planting times. No specific seeding
rate is given in order to allow for custom seed mixes based on site
characteristics and season. However, permanent seed inclusion in the
6.24.2 Rev. 5/13

Practice Standards and Specifications
mixture should total 15 pounds of pure live seed (PLS) per acre drilled or 15
to 20 pounds PLS per acre broadcast applied. At least four species should
be selected for the mixture, including one species from each type (warm
season, cold season, wetland); selection of more than four species is
recommended for increasing chances of successful vegetation establishment.
If other species such as wildflowers are added to the mix, they should not be
counted in the minimum seeding rate for grasses.
Seedbed Preparation Disturbed soils within riparian areas must be amended to provide an optimum
environment for seed germination and seedling growth. The surface soil must be
loose enough for water infiltration and root penetration. The pH of the soil must
be such that it is not toxic and nutrients are available. Riparian areas are
generally considered rich in nutrients due to flooding and deposition, however,
these areas can be highly variable (i.e., narrow steep corridors in the mountains,
artificial fill material on top of alluvial floodplains in the Piedmont). Soil
analysis should be performed to determine nutrient and lime needs of each site.
Appropriate levels of phosphorus and potassium are critical for permanent seed
establishment. Appropriate pH levels are between 5.5 and 7. Riparian buffers
regulated for nutrient management may be limited to a single application of
fertilizer.
Construction activities within the riparian area can greatly compact soils.
Suitable mechanical means such as disking, raking, or harrowing must be
employed to loosen the compacted soil prior to seeding.
Planting Seeding rates of native herbaceous species are given in pounds of pure live seed
due to the variability in the germination and purity of native seed. Reputable
seed growers and dealers will buy and sell native seed by the pure live seed
pound. When the seed is sown, the amount of pure live seed must be converted
to pounds of bulk (actual) seed to sow the proper amount of seed. The amount of
bulk (actual) seed is calculated by dividing the amount of pure live seed by the
germination and purity as decimals. For example, a ten pound pure live seed per
acre seeding rate with seed with 50 percent germination and 50 percent purity
will require 40 pounds of bulk (actual) seed (40-10/0.5*0.5).
Planting dates given in the seeding mixture specifications (Tables 6.24b — 6.24d)
are designated as "optimal". Seeds properly sown within the "optimal" dates
have a high probability of success. It is also possible to have satisfactory
establishment when seeding outside these dates. However, as you deviate from
them, the probability of failure increases rapidly. Always take this into account
when scheduling land -disturbing activities. Many perennial native species
require a cold, wet treatment (stratification) before they will germinate at the rate
noted on the seed tag. Seeding before the local date of last frost usually provides
enough exposure to cold moist conditions to meet these requirements. Seeding
before that date also insures early germination that will decrease the chance that
seedlings will be affected by summer droughts. Seed sown late may not
germinate until the next year after it has laid in the ground through a winter.
Apply seed uniformly with a cyclone seeder, drop -type spreader, drill, or
hydroseeder on a firm, friable seedbed. When using a drill, equipment should be
Rev. 5/13 6.24.3

Practice Standards and Specifications
calibrated in the field for the desired seeding rate. In fine soils, seeds should be
drilled 1/4 to '/2 inch. Ill coarse sandy soils, seeds should be planted no deeper
than 3/4 inch. Cover broadcast seed by lightly raking or chain dragging; then firm
the surface with a roller or cultipacker to provide good seed contact.
Mulch all plantings immediately after seeding (Practice 6.14, Mulching). If
planting on stream banks steeper than 10 percent or areas subject to flooding, a
biodegradable RECP (Practice 6.17, Rolled Erosion Control Products) is
recommended to hold seed and soil in place.
6.24.4 Rev. 5/13

Practice Standards and Specifications
Table 6.24b Permanent Seeding Recommendations -- Mountain Region
*Pick at least four species, including one from each type.
Rev. 5/13 6.24.5
Percentage of
Optimal Planting
Soil Drainage
Shade
Common Name
Scientific Name
Cultivars
Type*
Mix
Dates
Adaptation
Tolerance
Height
Cave -in -rock -- well drained
Blackwell -- well drained
Warm
Cultivar
Switchgrass
Panicumvirgatum
Shelterwelldrained
10-15%
Dec. 1 -Apr. 15
Poor
6
Kanlow -- poorly drained
Season
Dependent
Carthage -- well drained
Sorghastrum
Warm
Well -drained to
Indiangrass
Rumsey, Osage, Cheyenne
10-30%
Dec.1 -Apr. 15
Poor
6
nutans
Season
Droughty
Dichanthelium
Warm
Poorly -drained to
Deertongue
Tioga
5-250/c
Dec.1 -Apr. 15
Moderate
6
clandestinum
Season
Droughty
Andropogon
Warm
Well -drained to
Big Bluestem
Roundtree, Kaw, Earl
10-30%
Dec.1 -Apr. 15
Poor
6
gerardii
Season
Droughty
Schizachyrium
Warm
Well -drained to
Little Bluestem
Aldous, Cimarron
10-30%
Dec.1 -Apr. 15
Poor
4
scoparium
Season
Droughty
Warm
to
SweetWoodreed
Cinnaarundinacea
1-10%oorly-drained
Dec.Dec.1 -Apr. 15
Moderate
5
Season
Well -drained
Warm
Rice Cutgrass
Leersia oryzoides
5-250/c
Dec.1 -Apr. 15
Poorly -drained
Poor
5
Season
Redtop
Warm
Panicum rigidulum
10-200/c
Dec.1 -Apr. 15
Well -drained
Poor
3.5
Panicgrass
Season
Eastern
Tripsacum
Warm
Well -drained to
10-200/c
Dec.1 -Apr. 15
Poor
4.5
Gammagrass
dactyloides
Season
Poorly -drained
Warm
Well -drained to
Purple top
Tridens flavus
5-10%roughty
Dec.Dec.1 -Apr. 15
Poor
2.5
Season
Chasmanthium
Cold
Mar.1 -May 15,
Well -drained to
Indian Woodoats
1-10%
Moderate
4
latifolium
Season
July 15 -Aug. 15
Droughty
Cold
Mar.1 -May 15,
Well -drained to
UrginiaVl(Idrye
Elymusvirginicus
5-25%
Moderate
3
Season
July 15 -Aug. 15
Droughty
Eastern Bottle
Cold
Mar.1 -May 15,
Well -drained to
Elymus hystrix
5-10%
Moderate
3
brush Grass
Season
July 15 -Aug. 15
Droughty
Cold
Mar.1-May 15,
Winter Bentgrass
Agrostis hyemalis
10-200/c
Well -drained
Moderate
3.5
Season
July 15 -Aug. 15
Cold
Mar.1-May 15,
Rough Bentgrass
Agostis scabra
10-200/c
Poorly -drained
Poor
2.5
Season
July 15 -Aug. 15
Dec:1- May 15,
Soft Rush
Juncuseffusus
Wetland
1-10%
Poorly -drained
Poor
4
Aug. 15 - Oct.. 15
Dec, 1-May15,
Shallow Sedge
Carex lurida
Wetland
1-10%
Poorl drained
y
'Poor
3
Aug. 15 - Oct.. 15
Dec.1- May 15,
Fox Sedge
Carexvulpinoidea
Wetland
1-10%
Poorl drained
y
'Poor
3
Aug. 15 - Oct.. 15
Dec1- May 1,5,
Leathery Rush
Juncuscoriaceus
Wetland
2-50/c
Poorly -drained
Poor
2
Aug. 15 - Oct.. 15
*Pick at least four species, including one from each type.
Rev. 5/13 6.24.5

Practice Standards and Specifications
Table 6.24c Permanent Seeding Recommendations -- Piedmont Region
* Pick at least four species, including one from each type.
6.24.6 Rev. 5/13
Percentage of
Optimal Planting
Soil Drainage
Shade
Common Name
Scientific Name
Cultivars
Type*
Mix
Dates
Adaptation
Tolerance
Height
Switchgrass
Panicumvirgatum
Blackwell -- well drained
Shelter --well drained
Warm
Cultivar
10-15%
Dec.1 - Apr. 1
Poor
6
Kanlow -- poorly drained
Season
Dependent
Carthage -- well drained
Switchgrass
Panicum virgatum
Warm
Cultivar
10-15%
Dec. 1 -May 1
Poor
6
Alamo -- poorly -drained
Season
Dependent
Indiangrass
Sorghastrum
Warm
Well -drained to
10-30%
Dec.1 - Apr. 1
Poor
6
nutans
Rumsey, Osage, Cheyenne
Season
Droughty
Indiangrass
Sorghastrum
Warm
Well -drained to
10-30%
Dec. 1 -May 1
Poor
6
nutans
Lometa
Season
Droughty
Deertongue
Dichanthelium
Warm
Poorly -drained to
5-25%
Dec.1 - Apr. 1
Moderate
2
clandestinum
Tioga
Season
Droughty
BigBluestem
Andropogon
Warm
Well -drained to
10-30%
Dec.1 - Apr. 1
Poor
6
gerardii
Roundtree, Kaw, Earl
Season
Droughty
LittleBluestem
Schizachyrium
Warm
Well -drained to
10-30%
Dec.1 - Apr. 1
Poor
4
scoparium
Cimarron
Season
Droughty
Warm
Poorly -drained to
1-10%
Dec.1 - Apr. 1
Moderate
5
Sweet Woodreed
Cinnaarundinacea
Season
Well -drained
Warm
5-25%
Dec.1 - Apr. 1
Poorly-drainec
Poor
5
Rice Cutgrass
Leersia oryzoides
Season
Warm
10-20%
Dec.1 - Apr. 1
Well -drained
Poor
3.5
Redtop Panicgrass
Panicum rigidulum
Season
Warm
10-20%
Dec.1 - Apr. 1
Poorly-drainec
Moderate
3.5
Beaked Panicgrass
Panicum anceps
Season
Warm
Well -drained to
5-10%
Dec.1 - Apr. 1
Poor
2.5
Purple top
T ridens flavus
Season
Droughty
Eastern
Tripsacum
Warm
Well -drained to
5-10%
Dec.1 - Apr. 1
Poor
4.5
Gammagrass
dactyloides
Season
Poorly-drainec
Chasmanthium
Cold
Feb. 15 -Apr. 1,
Well -drained to
1-10%
Moderate
4
Indian Woodoats
Iatifolium
Season
Aug. 15 -Oct. 15
Droughty
Cold
Feb. 15 -Apr. 1,
Well -drained to
5-25%
Moderate
3
MrginiaWildrye
Elymusvrginicus
Season
Aug. 15 -Oct. 15
Droughty
Eastern Bottle-
Cold
Feb. 15 -Apr. 1,
Well -drained to
5-10%
Moderate
3
brush Grass
Elym us hystrix
Season
Aug. 15 -Oct. 15
Droughty
Cold
Feb. 15 -Apr. 1,
10-20%
Poorly-drainec
Poor
2.5
Rough Bentgrass
Agrostis scabra
Season
Aug. 15 -Oct. 15
Cold
Feb. 15 -Apr. 1,
2-5%
Well -drained
Moderate
3.5
Winter Bentgrass
Agrostishyemalis
Season
Aug. 15 -Oct. 15
Dec1 - May 1, ',
Wetland
1-10%
Poorly drainec
Poor
4
Soft Rush
Juncus effusus
Sep..;1 - Nov 1
Dec 1-May1
Wetland
1-10%
Poorly drainec
Poor
3
Shallow Sedge
Carex lunda
Sep 1 - Nov 1
'
Dec1 May 1
Wetland
1-10%
Poorly drainec
Poor
3
Fox Sedge
Carex vulpinoidea
Sep 1 - Nov 1
Dec '1 May 1
Wetland
2-5%
Poorly drainec
Poor
2
Leathery Rush
Juncus conaceus
Sep1 - Nov 1
* Pick at least four species, including one from each type.
6.24.6 Rev. 5/13

Practice Standards and Specifications
Table 6.24d Permanent Seeding Recommendations -- Coastal Plain Region
* Only Lometa in eastern coastal plain (Plant Hardiness Zone 8).
* Pick at least four species, including one from each type.
Rev. 5/13 6.24.7
Percentage of
Optimal Planting
Soil Drainage
Shade
Common Name
Scientific Name
Cultivars
Type*
Mix
Dates
Adaptation
Tolerance
Height
Switchgrass
Panicum virgatum
Blackwell -- well drained
Shelter --well drained
Warm
Cultivar
Kanlow -- poorly drained
Season
10-15%
Dec. 1- Apr.1
Dependent
Poor
6
Carthage -- well drained
Switchgrass
Panicum virgatum
Warm
Cultivar
10-15%
Dec. 1- May 1
Poor
6
Alamo -- poorly -drained
Season
Dependent
Indiangrass*
Sorghastrum
Warm
Well -drained to
10-30%
Dec. 1 - Apr. 1
Poor
6
nutans*
Rumsey, Osage, Cheyenne
Season
Droughty
Indiangrass*
Sorghastrum
Warm
Well -drained to
10-30%
Dec.1 May 1
Poor
6
nutans*
Lometa
Season
Droughty
Big Bluestem
Andropogon
Warm
Well -drained to
10-30%
Dec.1-Ppr.1
Poor
6
g erardii
Earl
Season
Droughty
Little Bluestem
Schizachyrium
Warm
Well -drained to
scoparium
Cimarron
Season
10 30%
Dec.1 Ppr.1
Droughty
Poor
4
Warm
Poorlydrained to
1-10%
Dec. 1 - Apr. 1
Moderate
5
Sweet Woodreed
Cinnaarundinacea
Season
Well -drained
Warm
5-25%
Dec. 1 - Apr. 1
Poorly -drained
Poor
5
Rice Cutgrass
Leersia oryzoides
Season
Redtop
Warm
10-20%
Dec. 1 - Apr. 1
Well -drained
Poor
3.5
Panicgrass
Panicum rigidulum
Season
Beakec
Warm
10-20%
Dec. 1 - Apr. 1
Poorly -drained
Moderate
3.5
Panicgrass
Panicum anceps
Season
Eastern
Tripsacum
Warm
Well -drained to
5-10%
Dec. 1 - Apr. 1
Poor
4.5
Gammagrass
datyoides
Season
Poorly -drained
Warm
Well -drained to
5-10%
Dec. 1 - Apr. 1
Poor
2.5
Purple top
T ridens flavus
Season
Droughty
Chasmanthium
Cold
Feb. 15 -Mar. 20,
Well -drained to
1-10%
Moderate
4
Indian Woodoats
Iatifolium
Season
Sep. 1- Nov.1
Droughty
Cold
Feb. 15 -Mar. 20,
Well -drained to
5-25%
Moderate
3
Mrginia Wildrye
Elymusvirginicus
Season
Sep. 1- Nov.1
Droughty
Cold
Feb. 15- Mar. 20,
10-20%
Poorly -drained
Poor
2.5
Rough Bentgrass
Agrostis scabra
Season
Sep. 1- Nov.1
Wetland
1-10%
Dec 1 -Apr 15
Poorly -drained
Poor
4
Soft Rush
Juncus effusus
Wetland
1-10%
Dec, 1 - Apr, 15
Poorly -drained
Poor
3
Shallow Sedge
Carex lunda
Wetland
1-10%
Dec 1 -Apr 15
Poorly -drained
Poor
3
Fox Sedge
Carex vulpinoidea
Wetland
2-5%
Dec 1 -Apr 15
Poorly -drained
Poor
2
Leathery Rush
Juncusconaceus
* Only Lometa in eastern coastal plain (Plant Hardiness Zone 8).
* Pick at least four species, including one from each type.
Rev. 5/13 6.24.7

Practice Standards and Specifications
Maintenance Many of the recommended permanent grass species may require two
years for establishment, depending on site conditions. Inspect seeded
areas for failure and make necessary repairs, soil amendments, and
reseedings. If weedy exotic species have overtaken the area after the
first growing season, the invading species must be eradicated to allow
native species to grow. Native vegetations are difficult to manage and
take longer to establish. Monitor the site until long term stability has
been established.
6.24.8 Rev. 5/13

Practice Standards and Specifications
Definition A small, temporary ponding basin formed by an embankment or excavation
to capture sediment.
Purpose To detain sediment -laden runoff and trap the sediment to protect receiving
streams, lakes, drainage systems, and protect adjacent property.
Conditions Where Specific criteria for installation of a temporary sediment trap are as follows:
Practice Applies • At the outlets of diversions, channels, slope drains, or other runoff
conveyances that discharge sediment -laden water.
• Below areas that are draining 5 acres or less.
• Where access can be maintained for sediment removal and proper
disposal.
• In the approach to a stormwater inlet located below a disturbed area as
part of an inlet protection system.
• Structure life limited to 2 years.
A temporary sediment trap should not be located in an intermittent or
perennial stream.
Planning Select locations for sediment traps during site evaluation. Note natural
Considerations drainage divides and select trap sites so that runoff from potential sediment -
producing areas can easily be diverted into the traps. Ensure the drainage
areas for each trap does not exceed 5 acres. Install temporary sediment traps
before land disturbing takes place within the drainage area.
Make traps readily accessible for periodic sediment removal and other
necessary maintenance. Plan locations for sediment disposal as part of trap
site selection. Clearly designate all disposal areas on the plans.
In preparing plans for sediment traps, it is important to consider provisions to
protect the embankment from failure from storm runoff that exceeds the design
capacity. Locate bypass outlets so that flow will not damage the embankment.
Direct emergency bypasses to undisturbed natural, stable areas. If a bypass is
not possible and failure would have severe consequences, consider alternative
sites.
Sediment trapping is achieved primarily by settling within a pool formed by
an embankment. The sediment pool may also be formed by excavation, or by
a combination of excavation and embankment. Sediment -trapping efficiency
is a function of surface area and inflow rate (Practice 6.6 1, Sediment Basin).
Therefore, maximize the surface area in the design. Because porous baffles
improve flow distribution across the basin, high length to width ratios are not
necessary to reduce short-circuiting and to optimize efficiency.
Because well planned sediment traps are key measures to preventing off-
site sedimentation, they should be installed in the first stages of project
development.
Rev. 6/06 6.60.1

v
Design Criteria
Summary:
Primary Spillway:
Maximum Drainage Area:
Minimum Volume:
Minimum Surface Area:
Minimum L/W Ratio:
Minimum Depth:
Maximum Height:
Dewatering Mechanism:
Minimum Dewatering Time:
Baffles Required:
Temporary Sediment Trap
Stone Spillway
5 acres
3600 cubic feet per acre of disturbed area
435 square feet per cfs of Qlo peak inflow
2:1
3.5 feet, 1.5 feet excavated below grade
Weir elevation 3.5 feet above grade
Stone Spillway
N/A
Storage capacity—Provide a minimum volume of 3600 ft3/acre of disturbed
area draining into the basin. Required storage volume may also be determined
by modeling the soil loss with the Revised Universal Soil Loss Equation or
other acceptable methods. Measure volume to the crest elevation of the stone
spillway outlet.
Trap cleanout—Remove sediment from the trap, and restore the capacity
to original trap dimensions when sediment has accumulated to one-half the
design depth.
Trap efficiency—The following design elements must be provided for
adequate trapping efficiency:
• Provide a surface area of 0.01 acres (435 square feet) per cfs based on the
10 -year storm;
• Convey runoff into the basin through stable diversions or temporary slope
drains;
• Locate sediment inflow to the basin away from the dam to prevent short
circuits from inlets to the outlet;
• Provide porous baffles (Practice 6.65, Porous Baffles);
• Excavate 1.5 feet of the depth of the basin below grade, and provide
minimum storage depth of 2 feet above grade.
Embankment—Ensure that embankments for temporary sediment traps do
not exceed 5 feet in height. Measure from the center line of the original ground
surface to the top of the embankment. Keep the crest of the spillway outlet
a minimum of 1.5 feet below the settled top of the embankment. Freeboard
may be added to the embankment height to allow flow through a designated
bypass location. Construct embankments with a minimum top width of 5 feet
and side slopes of 2:1 or flatter. Machine compact embankments.
Excavation—Where sediment pools are formed or enlarged by excavation,
keep side slopes at 2:1 or flatter for safety.
Outlet section—Construct the sediment trap outlet using a stone section of
the embankment located at the low point in the basin. The stone section serves
two purposes: (1) the top section serves as a non-erosive spillway outlet for
flood flows; and (2) the bottom section provides a means of dewatering the
basin between runoff events.
Stone size—Construct the outlet using well -graded stones with a dso size of 9
inches (Class B erosion control stone is recommended,) and a maximum stone
6.60.2 Rev. 6/06

Practice Standards and Specifications
size of 14 inches. The entire upstream face of the rock structure should be
covered with fine gravel (NCDOT #57 or #5 wash stone) a minimum of 1 foot
thick to reduce the drainage rate.
Side slopes—Keep the side slopes of the spillway section at 2:1 or flatter.
To protect the embankment, keep the sides of the spillway at least 21 inches
thick.
Depth—The basin should be excavated 1.5 feet below grade.
Stone spillway height—The sediment storage depth should be a minimum of
2 feet and a maximum of 3.5 feet above grade.
Protection from piping—Place filter cloth on the foundation below the riprap
to prevent piping. An alternative would be to excavate a keyway trench across
the riprap foundation and up the sides to the height of the dam.
Weir length and depth—Keep the spillway weir at least 4 feet long and sized
to pass the peak discharge of the 10 -year storm (Figure 6.60a). A maximum
flow depth of six inches, a minimum freeboard of 1 foot, and maximum side
slopes of 2:1 are recommended. Weir length may be selected from Table 6.60a
shown for most site locations in North Carolina.
Cross -Section 12" min. of NCI) OT #5
or #57 washed stone
Design settled
top
z ri tph tt�{ i 1j 5'
---- - ---
777
7,7 maX
ll
2' to 3.5'
----I-----------
3600 cu ft/acre
?,V
filter
fabric
ti
filter
fabric
Plan View
5'
i---- - 11.5' -min----------- ----
�.
it -
5'
Overfill 6" for
r settlement
, , .i, , Emergency by -
4' ass 6" below
min. settled
top of
dam
3'
min.
Figure 6.60a Plan view and cross-section view of a temporary sediment trap.
Natural
Ground
Rev. 6/06 6.60.3

v
Table 6.60a
Design of Spillways
Drainage Area Weir Length'
(acres) (ft)
1 4.0
2 6.0
3 8.0
4 10.0
5 12.0
' Dimensions shown are minimum.
Construction 1. Clear, grub, and strip the area under the embankment of all vegetation and
Specifications root mat. Remove all surface soil containing high amounts of organic matter,
and stockpile or dispose of it properly. Haul all objectionable material to the
designated disposal area.
2. Ensure that fill material for the embankment is free of roots, woody
vegetation, organic matter, and other objectionable material. Place the fill in
lifts not to exceed 9 inches, and machine compact it. Over fill the embankment
6 inches to allow for settlement.
3. Construct the outlet section in the embankment. Protect the connection
between the riprap and the soil from piping by using filter fabric or a keyway
cutoff trench between the riprap structure and soil.
• Place the filter fabric between the riprap and the soil. Extend the fabric
across the spillway foundation and sides to the top of the dam; or
• Excavate a keyway trench along the center line of the spillway foundation
extending up the sides to the height of the dam. The trench should be at
least 2 feet deep and 2 feet wide with 1:1 side slopes.
4. Clear the pond area below the elevation of the crest of the spillway to
facilitate sediment cleanout.
5. All cut and fill slopes should be 2:1 or flatter.
6. Ensure that the stone (drainage) section of the embankment has a
minimum bottom width of 3 feet and maximum side slopes of 1:1 that extend
to the bottom of the spillway section.
7. Construct the minimum finished stone spillway bottom width, as shown
on the plans, with 2:1 side slopes extending to the top of the over filled
embankment. Keep the thickness of the sides of the spillway outlet structure
at a minimum of 21 inches. The weir must be level and constructed to
grade to assure design capacity.
8. Material used in the stone section should be a well -graded mixture of stone
with a d50 size of 9 inches (class B erosion control stone is recommended) and
a maximum stone size of 14 inches. The stone may be machine placed and the
smaller stones worked into the voids of the larger stones. The stone should be
hard, angular, and highly weather -resistant.
9. Discharge inlet water into the basin in a manner to prevent erosion. Use
temporary slope drains or diversions with outlet protection to divert sediment -
laden water to the upper end of the pool area to improve basin trap efficiency
(References: Runoff Control Measures and Outlet Protection).
6.60.4 Rev. 6/06

Practice Standards and Specifications
10. Ensure that the stone spillway outlet section extends downstream past the
toe of the embankment until stable conditions are reached and outlet velocity
is acceptable for the receiving stream. Keep the edges of the stone outlet
section flush with the surrounding ground, and shape the center to confine the
outflow stream (References: Outlet Protection).
11. Direct emergency bypass to natural, stable areas. Locate bypass outlets
so that flow will not damage the embankment.
12. Stabilize the embankment and all disturbed areas above the sediment pool
and downstream from the trap immediately after construction (References:
Surface Stabilization).
13. Show the distance from the top of the spillway to the sediment cleanout
level (1/2 the design depth) on the plans and mark it in the field.
14. Install porous baffles as specified in Practice 6.65, Porous Bales.
Maintenance Inspect temporary sediment traps at least weekly and after each significant ('/z
inch or greater) rainfall event and repair immediately. Remove sediment, and
restore the trap to its original dimensions when the sediment has accumulated
to one-half the design depth of the trap. Place the sediment that is removed in
the designated disposal area, and replace the part of the gravel facing that is
impaired by sediment.
Check the structure for damage from erosion or piping. Periodically check the
depth of the spillway to ensure it is a minimum of 1.5 feet below the low point
of the embankment. Immediately fill any settlement of the embankment to
slightly above design grade. Any riprap displaced from the spillway must
be replaced immediately.
After all sediment -producing areas have been permanently stabilized, remove
the structure and all unstable sediment. Smooth the area to blend with the
adjoining areas, and stabilize properly (References: Surface Stabilization).
References Outlet Protection
6.41, Outlet Stabilization Structure
Runoff Control Measures
6.20, Temporary Diversions
6.2 1, Permanent Diversions
6.22, Diversion Dike (Perimeter Protection)
6.23, Right-of-way Diversion (Water Bars)
Surface Stabilization
6. 10, Temporary Seeding
6. 11, Permanent Seeding
6.15, Riprap
Sediment Traps and Barriers
6.6 1, Sediment Basins
6.64, Skimmer Basins
6.65, Porous Baffles
North Carolina Department of Transportation
Standard Specifications for Roads and Structures
Rev. 6/06 6.60.5

Practice Standards and Specifications
Definition A temporary sediment control measure consisting of fabric buried at the
bottom, stretched, and supported by posts.
Purpose To retain sediment from small disturbed areas by reducing the velocity of
sheet flows to allow sediment deposition.
Conditions Where Below small -disturbed areas that are less then 1/4 acre per 100 feet of fence.
Practice Applies Where runoff can be stored behind the sediment fence without damaging the
fence or the submerged area behind the fence.
Do not install sediment fences across streams, ditches, or waterways, or
other areas of concentrated flow.
Sediment fence should be placed along topographic elevation contours, where
it can intercept stormwater runoff that is in dispersed sheet flow. Sediment
fence should not be used alone below graded slopes greater than 10 feet in
height.
Planning A sediment fence is a system to retain sediment on the construction site. The
Considerations fence retains sediment primarily by retarding flow and promoting deposition.
In operation, generally the fence becomes clogged with fine particles, which
reduce the flow rate. This causes a pond to develop behind the fence. The
designer should anticipate ponding and provide sufficient storage areas and
overflow outlets to prevent flows from overtopping the fence. Since sediment
fences are not designed to withstand high water levels, locate them so that
only shallow pools can form. Tie the ends of a sediment fence into higher
ground to prevent flow around the end of the fence before the pool reaches
design level. Curling each end of the fence uphill in a "J" pattern may be
appropriate to prevent end flow. Provide stabilized outlets to protect the fence
system and release storm flows that exceed the design storm.
Deposition occurs as the storage pool forms behind the fence. The designer can
direct flows to specified deposition areas through appropriate positioning of
the fence or by providing an excavated area behind the fence. Plan deposition
areas at accessible points to promote routine cleanout and maintenance. Show
deposition areas in the erosion and sedimentation control plan. A sediment
fence acts as a diversion if placed slightly off the contour. A maximum slope
of 2 percent is recommended. This technique may be used to control shallow,
uniform flows from small disturbed areas and to deliver sediment -laden water
to deposition areas. The anchoring of the toe of the fence should be reinforced
with 12 inches of NC DOT #5 or #57 washed stone when flow will run parallel
to the toe of the fence.
Sediment fences serve no function along ridges or near drainage divides where
there is little movement of water. Confining or diverting runoff unnecessarily
with a sediment fence may create erosion and sedimentation problems that
would not otherwise occur.
Rev. 5/13 6.62.1

v
Straw barriers have only a 0-20% trapping efficiency and are inadequate. Straw
bales may not be used in place of sediment fence. Prefabricated sediment fence
with the fabric already stapled to thin wooden posts does not meet minimum
standards specified later in this section.
Anchoring of sediment fence is critical. The toe of the fabric must be anchored
in a trench backfilled with compacted earth. Mechanical compaction must be
provided in order for the fence to effectively pond runoff.
Design Criteria Ensure that drainage area is no greater than 1/4 acre per 100 feet of fence. This
is the maximum drainage area when the slope is less than 2 percent. Where
all runoff is to be stored behind the fence, ensure that the maximum slope
length behind a sediment fence does not exceed the specifications shown in
Table 6.62a. The shorter slope length allowed for steeper slopes will greatly
reduce the maximum drainage area. For example, a 10 20 % slope may have
a maximum slope length of 25 feet. For a 100 -foot length of sediment fence,
the drainage area would be 25ft X 100ft = 2500sq.ft., or 0.06 acres.
Table 6.62a Maximum
Slope Length and Slope for
which Sediment Fence is
Applicable
Slope Slope Length (ft) Maximum Area (ft2)
<2% 100 10,000
2 to 5% 75 7,500
5 to 10% 50 5,000
10 to 20% 25 2,500
>20% 15 1,500
Make the fence stable for the 10 -year peak storm runoff.
Ensure that the depth of impounded water does not exceed 1.5 feet at any point
along the fence.
If non-erosive outlets are provided, slope length may be increased beyond
that shown in Table 6.62a, but runoff from the area should be determined and
bypass capacity and erosion potential along the fence must be checked. The
velocity of the flow at the outlet or along the fence should be in keeping with
Table 8.05d, Appendix 8.05.
Provide a riprap splash pad or other outlet protection device for any point
where flow may overtop the sediment fence, such as natural depressions or
swales. Ensure that the maximum height of the fence at a protected, reinforced
outlet does not exceed 2 feet and that support post spacing does not exceed 4
feet.
The design life of a synthetic sediment fence should be 6 months.
Construction MATERIALS
Specifications L Use a synthetic filter fabric of at least 95% by weight of polyolefins or
polyester, which is certified by the manufacturer or supplier as conforming to
the requirements in ASTM D 6461, which is shown in part in Table 6.62b.
Synthetic filter fabric should contain ultraviolet ray inhibitors and stabilizers
to provide a minimum of 6 months of expected usable construction life at a
temperature range of 0 to 120° F.
6.62.2 Rev. 5/13

Practice Standards and Specifications
2. Ensure that posts for sediment fences are 1.25 lb/linear ft minimum
steel with a minimum length of 5 feet. Make sure that steel posts have
projections to facilitate fastening the fabric.
3. For reinforcement of standard strength filter fabric, use wire fence with a
minimum 14 gauge and a maximum mesh spacing of 6 inches.
Table 6.62b Specifications For Sediment Fence Fabric
Temporary Silt Fence Material Property Requirements
Supported' Un -Supported' Type of
Test Material Units Silt Fence Silt Fence Value
Grab Strength ASTM D 4632 N (lbs)
Machine Direction 400 550 MARV
(90) (90)
X -Machine Direction 400 450 MARV
(90) (90)
Permittivity2 ASTM D 4491 sec -1 0.05 0.05 MARV
Apparent Opening Size ASTM D 4751 mm 0.60 0.60 Max. ARV3
(US Sieve #) (30) (30)
70% after 70% after
Ultraviolet Stability ASTM D 4355 Retained 500h of exposure 500h of exposure Typical
Strength
Silt Fence support shall consist of 14 gage steel wire with a mesh spacing of 150 mm (6 inches), or prefabricated poylmer mesh of
equivalent strength.
2 These default values are based on empirical evidence with a variety of sediment. For environmentally sensitive areas, a review of
previous experience and/or site or regionally specific geotextile tests in accordance with Test Method D 5141 should be performed
by the agency to confirm suitability of these requirements.
3 As measured in accordance with Test Method D 4632.
CONSTRUCTION
1. Construct the sediment barrier of standard strength or extra strength
synthetic filter fabrics.
2. Ensure that the height of the sediment fence does not exceed 24 inches
above the ground surface. (Higher fences may impound volumes of water
sufficient to cause failure of the structure.)
3. Construct the filter fabric from a continuous roll cut to the length of the
barrier to avoid joints. When joints are necessary, securely fasten the filter
cloth only at a support post with 4 feet minimum overlap to the next post.
4. Support standard strength filter fabric by wire mesh fastened securely to
the upslope side of the posts. Extend the wire mesh support to the bottom of
the trench. Fasten the wire reinforcement, then fabric on the upslope side of
the fence post. Wire or plastic zip ties should have minimum 50 pound tensile
strength.
5. When a wire mesh support fence is used, space posts a maximum of 8 feet
apart. Support posts should be driven securely into the ground a minimum of
24 inches.
6. Extra strength filter fabric with 6 feet post spacing does not require wire
mesh support fence. Securely fasten the filter fabric directly to posts. Wire or
plastic zip ties should have minimum 50 pound tensile strength.
Rev. 5/13 6.62.3

v
7. Excavate a trench approximately 4 inches wide and 8 inches deep along
the proposed line of posts and upslope from the barrier (Figure 6.62a).
8. Place 12 inches of the fabric along the bottom and side of the trench.
9. Backfill the trench with soil placed over the filter fabric and compact.
Thorough compaction of the backfill is critical to silt fence performance.
10. Do not attach filter fabric to existing trees.
SEDIMENT FENCE INSTALLATION USING THE SLICING METHOD
Instead of excavating a trench, placing fabric and then backfilling trench,
sediment fence may be installed using specially designed equipment that
inserts the fabric into a cut sliced in the ground with a disc (Figure 6.62b).
Installation 1. The base of both end posts should be at least one foot higher than the
middle of the fence. Check with a level if necessary.
Specifications
2. Install posts 4 feet apart in critical areas and 6 feet apart on standard
applications.
3. Install posts 2 feet deep on the downstream side of the silt fence, and
as close as possible to the fabric, enabling posts to support the fabric from
upstream water pressure.
4. Install posts with the nipples facing away from the silt fabric.
5. Attach the fabric to each post with three ties, all spaced within the top 8
inches of the fabric. Attach each tie diagonally 45 degrees through the fabric,
with each puncture at least 1 inch vertically apart. Also, each tie should be
positioned to hang on a post nipple when tightened to prevent sagging.
6. Wrap approximately 6 inches of fabric around the end posts and secure
with 3 ties.
7. No more than 24 inches of a 36 inch fabric is allowed above ground
level.
8. The installation should be checked and corrected for any deviations before
compaction.
9. Compaction is vitally important for effective results. Compact the soil
immediately next to the silt fence fabric with the front wheel of the tractor,
skid steer, or roller exerting at least 60 pounds per square inch. Compact the
upstream side first, and then each side twice for a total of 4 trips.
6.62.4
Rev. 5/13

Practice Standards and Specifications
Wire
fence
Cross -Section
View
Filter
Steel fabric Backfill trench
Natural
post and compact
ground
thoroughly
ti =�
min* •°.
24„ min
Figure 6.62a Installation detail of a sediment fence.
-al
id
6.62.5
Rev. 5/13

O
The Slicing Method
Ponding height
max 24"
Attach fabric to
upstream side of past
FLOW
Drive over each side of silt
fence 2 to 4 times with
device exerting 60 p.s.i. or
greater
POST SPACING:
6'' maxan open runs
4' max . on pooling areas0111111
POST F)FPTH-
2 feet
compacted soil compacted soil
No more than 24" ofa 36" fabric
is allowed above ground.
----------------------------------- Top of Fabric aT
Belt
top 8
Diagonal attachment
doubles strength,
L—j III.— ik __j
ATTACHMENT DETAILS:
rs Gather fabric at posts, if needed.
a Uiilize three ties per post, all within top 8" of fabric.
• Posiiion each iie diagonally, puncturing holes vertically
a minimum of 1" apart.
® Hang each iie ona post nipple and tighten securely.
Use cable ties (50lbs) or soft wire.
Roll of slit fence
Horizontal chisel point Slicina blade
3" width 4.7'
Vibratory plow Is not acceptable because of horizontal compaction
Figure 6.62b Schematics for using the slicing method to install a sediment fence. Adapted from Silt Fence that Works
6.62.6
Rev. 5/13
Post
installed
after
compaction
Silt Fence
r
Completed Installation
Vibratory plow Is not acceptable because of horizontal compaction
Figure 6.62b Schematics for using the slicing method to install a sediment fence. Adapted from Silt Fence that Works
6.62.6
Rev. 5/13

Practice Standards and Specifications
Maintenance Inspect sediment fences at least once a week and after each rainfall. Make any
required repairs immediately.
Should the fabric of a sediment fence collapse, tear, decompose or become
ineffective, replace it promptly.
Remove sediment deposits as necessary to provide adequate storage volume
for the next rain and to reduce pressure on the fence. Take care to avoid
undermining the fence during cleanout.
Remove all fencing materials and unstable sediment deposits and bring the
area to grade and stabilize it after the contributing drainage area has been
properly stabilized.
Refe re r1C@S ASTM D 6461-99. "Standard Specification for Silt Fence Materials" ASTM
International. For referenced ASTM standards, visit the ASTM website,
www.astm.org, or contactASTM Customer Service at [e-mail]. For
Annual Book ofASTM Standards volume information, refer to the standard's
Document Summary page on the ASTM website.
ASTM D 6462 — 03. "Standard Practice for Silt Fence Installation" ASTM
International. For referenced ASTM standards, visit the ASTM website,
www.astm.org, or contactASTM Customer Service at [e-mail]. For
Annual Book ofASTM Standards volume information, refer to the standard's
Document Summary page on the ASTM website.
C. Joel Sprague, PE, Silt Fence Performance Limits and Installation
Requirements. Sprague and Sprague Consulting Engineers and TRI/
Environmental, Inc.
Carpenter Erosion Control. http://www.tommy-sfm.com/
Kentucky Erosion Prevention and Sediment Control Field Manual, 2004.
Runoff Control Measures
6.20, Temporary Diversions
Outlet Protection
6.41, Outlet Stabilization Structure
Appendix
8.03, Estimating Runoff
Rev. 5/13 6.62.7

Practice Standards and Specifications
6.66 COMPOSTSOCK
c
• Definition A compost sock is a three-dimensional tubular sediment control and storm water
runoff device typically used for perimeter control of sediment and soluble
pollutants (such as phosphorous and petroleum hydrocarbon), on and around
construction activities. Compost socks trap sediment and other pollutants in
runoff water as it passes through the matrix of the sock and by allowing water to
temporarily pond behind the sock, allowing deposition of suspended solids.
Compost socks are also used to reduce runoff flow velocities on sloped surfaces.
Compost products acceptable for this application should meet the chemical,
physical and biological properties specified for Practice 6.18, Compost Blankets.
Figure 6.66a — Compost Sock
Photo Credit — Filtrexx International
Conditions Where Compost socks are to be installed down slope of disturbed areas requiring
Practice Applies erosion and sediment control. Compost socks are effective when installed
perpendicular to sheet flow, in areas where sediment accumulation of less
than six inches is anticipated. Acceptable applications include (Fifield,
2001):
• Site perimeters
• Below disturbed areas subject to sheet runoff, with minor sheet or rill
erosion. Compost socks should not be used alone below graded slopes
greater than 10 feet in height.
• Above graded slopes to serve as a diversion berm.
Rev. 5/13 6.66.1

Practice Standards and Specifications
• Check dams
• Along the toe of stream and channel banks
• Around area drains or inlets located in a storm drain system
• Around sensitive trees where trenching of silt fence is not beneficial for tree
survival or may unnecessarily disturb established vegetation.
• On paved surfaces where trenching of silt fence is impossible.
A compost sock can be applied to areas of sheet runoff, on slopes up to a 2:1
grade with a maximum height of 10 feet, around inlets, and in other disturbed
areas of construction sites requiring sediment control. Compost socks may also
be used in sensitive environmental areas, or where trenching may damage roots.
The weight of a filled sock (40 lbs / linear ft. for 8" diameter) effectively
prevents sediment migration beneath the sock. It is possible to drive over a
compost sock during construction (although not recommended); however, these
areas should be immediately repaired by manually moving the sock back into
place, if disturbed. Continued heavy construction traffic may destroy the fabric
mesh, reduce the dimensions, and reduce the effectiveness of the compost sock.
Vegetating the compost sock should be considered.
Planning Compost socks shall either be made on site or delivered to the jobsite
Considerations assembled. The sock shall be produced from a 5 mil thick continuous
HDPE or polypropylene, woven into a tubular mesh netting material, with
openings in the knitted mesh of '�/8» - 3%8(3-10mm). This shall then be filled with
compost meeting the specifications outlined in Practice 6.18, Compost Blankets,
with the exception of particle size, to the diameter of the sock. Compost sock
netting materials are also available in biodegradable plastics for areas where
removal and disposal are not desired (i.e., when using pre -seeded socks).
Compost socks contain the compost, maintaining its density and shape.
Compost socks should be installed parallel to the base of the slope or other
affected area, perpendicular to sheet flow. The sock should be installed a
minimum of 10 feet beyond the top of graded slopes. When runoff flows onto
the disturbed area from a land above the work zone, a second sock may be
constructed at the top of the slope in order to dissipate flows.
On locations where greater than a 200 -foot long section of ground is to be treated
with a compost sock, the sock lengths should be sleeved. After one sock section
(200 feet) is filled and tied off (knotted) or zip tied, the second sock section shall
be pulled over the first 1-2 feet and 'sleeved' creating an overlap. Once
overlapped, the second section is filled with compost starting at the sleeved area
to create a seamless appearance. The socks may be staked at the overlapped area
(where the sleeve is) to keep the sections together. Sleeving at the joints is
necessary because it reduces the opportunity for water to penetrate the joints
when installed in the field.
6.66.2 Rev. 5/13

Practice Standards and Specifications
Table 6.66a Compost Sock BMPs as Replacements for Current Erosion Control Practices
Photo credits: Filtrexx International
After filling, the compost sock must be staked in place. Oak or other durable
hardwood stakes 2"x 2" in cross section should be driven vertically plumb,
through the center of the compost sock. Stakes should be placed at a maximum
interval of 4 feet, or a maximum interval of 8 feet if the sock is placed in a 4 inch
trench. See Figure 6.66b. The stakes should be driven to a minimum depth of 12
inches, with a minimum of 3 inches protruding above the compost sock.
If the compost sock is to be left as part of the natural landscape, it may be seeded
at time of installation for establishment of permanent vegetation using the
seeding specification in the erosion and sedimentation control plan. A maximum
life of 2 years for photodegradable netting and 6 months for biodegradable
netting should be used for planning purposes.
Rev. 5/13 6.66.3

Practice Standards and Specifications
Compost socks may be used as check dams in ditches not exceeding 3 feet in
depth. Normally, 8 to 12 inch diameter socks should be used. Be sure to stake
the sock perpendicular to the slope of the ditch. When used as check dams,
installation should be similar to that of natural fiber wattles. The ends and
middle of the sock should be staked, and additional stakes placed at a 2 -foot
maximum interval. See Table 6.66b for spacing.
Design Criteria The sediment and pollutant removal process characteristic to a compost sock
allows deposition of settling solids. Ponding occurs when water flowing to the
sock accumulates faster than the hydraulic flow through rate of the sock.
Typically, initial hydraulic flow-through rates for a compost sock are 50%
greater than geotextile fabric (silt fence). However, installation and maintenance
is especially important for proper function and performance. Design
consideration should be given to the duration of the project, total area of
disturbance, rainfall/runoff potential, soil erosion potential, and sediment loading
when specifying a compost sock.
Runoff Flow:
The depth of runoff ponded above the compost sock should not exceed the height
of the compost sock. If overflow of the device is a possibility, a larger diameter
sock should be constructed, other sediment control devices may be used, or
management practices to reduce runoff should be installed. Alternatively, a
second sock may be constructed or used in combination with Practice 6.17,
Rolled Erosion Control Products or Practice 6.18, Compost Blankets to slow
runoff and reduce erosion.
Level Contour:
The compost sock should be placed on level contours to assist in dissipating low
concentrated flow into sheet flow and reducing runoff flow velocity. Do not
construct compost socks to concentrate runoff or channel water. Sheet flow of
water should be perpendicular to the sock at impact and un -concentrated.
Placing compost socks on undisturbed soil will reduce the potential for
undermining by concentrated runoff flows.
Runoff and Sediment Accumulation:
The compost sock should be placed at a 10 foot minimum distance away from the
toe of the slope to allow for proper runoff accumulation for sediment deposition
and to allow for maximum sediment storage capacity behind the device. On flat
areas, the sock should be placed at the edge of the land -disturbance.
End Around Flow:
In order to prevent water flowing around the ends of the compost sock, the ends
of the sock must be constructed pointing upslope so the ends are at a higher
elevation. A minimum of 10 linear feet at each end placed at a 30 degree angle is
recommended.
6.66.4 Rev. 5/13

Practice Standards and Specifications
Vegetated Compost Sock:
For permanent areas the compost sock can be directly seeded to allow vegetation
established directly on the device. Vegetation on and around the compost sock
will assist in slowing runoff velocity for increased deposition of pollutants. The
option of adding vegetation should be shown on the erosion and sedimentation
control plan. No additional soil amendments or fertilizer are required for
vegetation establishment in the vegetated compost sock.
Slope Spacing & Drainage Area:
Maximum drainage area to and spacing between the compost socks is dependent
on rainfall intensity and duration used for specific design/plan, slope steepness,
and width of area draining to the sock.
A compost sock across the full length of the slope is normally used to ensure that
stormwater does not break through at the intersection of socks placed end-to-end.
Ends are jointed together by sleeving one sock end into the other. The diameter
of the compost sock used will vary depending upon the steepness and length of
the slope; example slopes and slope lengths used with different diameter compost
socks are presented in Table 6.66b.
Table 6.66b - Compost Sock Spacing versus Channel Slope
Channel Slope (%) Spacing Between Socks (feet)
8 -inch Diameter Sock
12 -inch Diameter Sock
1 67
100
2 33
50
3 22
33
4 17
25
5 13
20
Source: B. Faucette — 2010
Material:
The compost media shall be derived from well -decomposed organic matter
source produced by controlled aerobic (biological) decomposition that has been
sanitized through the generation of heat and stabilized to the point that it is
appropriate for this particular application. Compost material shall be processed
through proper thermophilic composting, meeting the US Environmental
Protection Agency's definition for a `Process to Further Reduce Pathogens'
(PFRP), as defined at 40 CFR Part 503. The compost portion shall meet the
chemical, physical and biological properties specified in Practice 6.18, Compost
Blankets Table 6.18a, with the exception of particle size. Slightly more coarse
compost is recommended for the socks, as follows:
Particle Size Distribution
Sieve Size Percent Passing Selected Sieve Mesh Size, Dry Weight Basis
2" 99 % (3" Maximum Particle Size)
3/8" 30-50%
See Practice 6.18, Compost Blankets for complete information on compost
parameters and tests. Installer should provide documentation to support
compliance of testing required in the compost specification.
Rev. 5/13 6.66.5

Practice Standards and Specifications
This specification covers compost produced from various organic by-products,
for use as an erosion and sediment control measure on sloped areas. The
product's parameters will vary based on whether vegetation will be established
on the treated slope. Only compost products that meet all applicable state and
federal regulations pertaining to its production and distribution may be used in
this application. Approved compost products must meet related state and federal
chemical contaminant (e.g., heavy metals, pesticides, etc.) and pathogen limit
standards pertaining to the feedstocks (source materials) in which it are derived.
In regions subjected to higher rates of precipitation and/or greater rainfall
intensity, larger compost socks should be used. In these particular regions,
coarser compost products are preferred as the compost sock must allow for an
improved water percolation rate. The designer should check the flow rate per
foot of sock in order to ensure drainage rate of the compost sock being used is
adequate. The required flow rates are outlined in Table 6.66c.
Table 6.66c — Compost Sock Initial Flow Rates
Compost Sock
8 inch
12 inch
18 inch
24 inch
32 inch
Design Diameter
200mm
300mm
450mm
600mm
800mm
Maximum Slope
600 ft
750 ft
1,000 ft
1,300 ft
1,650 ft
Length (<2%)
(183m)
(229m)
(305m)
(396m)
(500m)
Hydraulic Flow
7.5 gpm/ft
11.3 gpm/ft
15.0 gpm/ft
22.5gpm/ft
30.0 gpm/ft
Through Rate
941/m/m
1411/m/m
1881/m/m
281 1/m/m
3741/m/m
Source: B. Faucette-2010
Construction INSTALLATION
Specifications I. Materials used in the compost sock must meet the specifications outlined
above and in Practice 6.18, Compost Blankets.
2. Compost socks should be located as shown on the erosion and sedimentation
control plan.
3. Prior to installation, clear all obstructions including rocks, clods, and other
debris greater than one inch that may interfere with proper function of the
compost sock.
4. Compost socks should be installed parallel to the toe of a graded slope, a
minimum of 10 feet beyond the toe of the slope. Socks located below flat
areas should be located at the edge of the land -disturbance. The ends of the
socks should be turned slightly up slope to prevent runoff from going around
the end of the socks.
5. Fill sock netting uniformly with compost to the desired length such that logs
do not deform.
6. Oak or other durable hardwood stakes 2" X 2" in cross section should be
driven vertically plumb, through the center of the compost sock. Stakes
should be placed at a maximum interval of 4 feet, or a maximum interval of 8
feet if the sock is placed in a 4 inch trench. See Figure 6.66b. The stakes
6.66.6 Rev. 5/13

Practice Standards and Specifications
should be driven to a minimum depth of 12 inches, with a minimum of 3
inches protruding above the compost sock.
7. In the event staking is not possible (i.e., when socks are used on pavement)
heavy concrete blocks shall be used behind the sock to hold it in place during
runoff events.
8. If the compost sock is to be left as part of the natural landscape, it may be
seeded at time of installation for establishment of permanent vegetation using
the seeding specification in the erosion and sedimentation control plan.
9. Compost socks are not to be used in perennial or intermittent streams.
Maintenance Inspect compost socks weekly and after each significant rainfall event (1/2 inch
or greater). Remove accumulated sediment and any debris. The compost sock
must be replaced if clogged or torn. If ponding becomes excessive, the sock may
need to be replaced with a larger diameter or a different measure. The sock
needs to be reinstalled if undermined or dislodged. The compost sock shall be
inspected until land disturbance is complete and the area above the measure has
been permanently stabilized.
DISPOSAL/RECYCLING
Compost media is a composted organic product recycled and manufactured from
locally generated organic, natural, and biologically based materials. Once all soil
has been stabilized and construction activity has been completed, the compost
media may be dispersed with a loader, rake, bulldozer or similar device and may
be incorporated into the soil as an amendment or left on the soil surface to aid in
permanent seeding or landscaping. Leaving the compost media on site reduces
removal and disposal costs compared to other sediment control devices. The
mesh netting material will be extracted from the media and disposed of properly.
The photodegradable mesh netting material will degrade in 2 to 5 years if left on
site. Biodegradable mesh netting material is available and does not need to be
extracted and disposed of, as it will completely decompose in approximately 6 to
12 months. Using biodegradable compost socks completely eliminates the need
and cost of removal and disposal.
Rev. 5/13 6,66,7

Compost Sock
3 IN.
FLOWAREATC) BE
PROTECTED
12 IN MIN.
-2 in x 2 in
STAKES
WOOD MULCH OR COMPOST
TO 1/2 HEIGHT OF LOG
LINTRENCHED INSTALLATION
Practice Standards and Specifications
3 IN.
FLOW
--d
12 IN MIN.
TRIENCHINTO
GROUND
4 IN. MIN.
Compost Sock
AREA TO BE
PROTECTED
f 2 in x 2 in
STAKES
NO.
OR ENTRENCHED INSTALLATION*
*THIS APPLICATION MAY NOT BE USED
WITH COMPOST SOCKS SMALLER THAN 12 IN_
ISOMETRICVIEW
Mulch or Cor
for Untrenched
Sheet Flow
Work Area
Figure 6.66b Compost Sock Installation
nowaV-A11�
k TO BE
FELTED
Compost Sock
Maryland Standards and Specifications
for Soil Erosion and Sediment Control,
2011, Maryland Department of
Environment, Water Management
Administration
6.66.8 Rev. 5/13

Practice Standards and Specifications
References Chapter 3 Vegetative Considerations
Chapter 6Practice Standard and Site Specifications
6. 10, Temporary Seeding
6.11, Permanent Seeding
6.17, Rolled Erosion Control Products
6.18, Compost Blankets
Tyler, R., A. Marks, B. Faucette. 2010. The Sustainable Site: Design
Manual for Green Infrastructure and Low Impact Development Forester
Press, Santa Barbara, CA.
Fifield, J. 2001. Designing for Effective Sediment and Erosion Control on
Construction Sites. Forester Press, Santa Barbara, CA.
Maryland Department of Environment, Water Management Administration,
2011, Maryland Standards and Specifications for Soil Erosion and Sediment
Control, Filter Log
Rev. 5/13 6.66.9