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NQNPOINT SOURCE POLLUTION CONTROL GUIDANCE,
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NQNPQINT SOURCE POLLUTION CONTROL GUIDANCE
CONSTRUCTION ACTIVITIES
CHAPTER 3
Selected Practices for Control, Construction Activities
In order to minimize the generation of nonpoint source pollutants resulting
from-construction activities and prevent the transport of these materials from
site areas, Best Management Practices must be selected in accordance with
specific natural conditions occurring in the vicinity. They include:
Physical and chemical characteristics of soils and geologic materials
to
Topography
£s£ Intensity, duration, and frequency of precipitation
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3-2
make the control more effective. They are discussed under "Good House-
Keeping Practices".
Storm water is not a pollutant by itself. Artificially high peak flows,
however, created by impervious surfaces covering the construction area
or by drainage structures which increase the velocity of runoff, will
generally act as generators of pollution by eroding sediments and other
materials from drainageways and stream channels, particulaly downstream
from the site area. Best Management Practices to control, or manage
storm water runoff are discussed in the section entitled "Storm Water
Management".
Control practices can be designed and installed as temporary or permanent
measures. Temporary measures are those that are used to correct detrimental
conditions that: develop during construction activities, were not predicted
during project design, or are temporarily needed to control erosion or
sediment problems that occur during construction but are not associated
with permanent measures, Permanent measures are those that are intended
to remain in place during the life of the project facilities.
Erosion and Sediment Control
Erosion and sediment control practices include providing protective
coverings of mulches, vegetation, netting, and other materials to exposed
soils and foundation materials; controlling the erosive and transport energy
of runoff water; and trapping sediments being transported by runoff from
the site area. Many management practices devised for water erosion and
sediment-control purposes also are useful for control of wind-generated
pollutants. Their location and orientation for the latter purpose are designed
on the basis of wind direction and velocity rather than that of surface
water flow.
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Protecting Exposed Ground Surfaces
Existing natural vegetation should be preserved as much as possible on
construction sites, particularly where grading, or soil disturbance is not
necessary. If removal of the vegetation is required, only a necessary
minimum of soil should be exposed at any one time. If the duration
of exposure is extensive and erosion probable, vegetation or some other
type of protective covering should be provided and/or sediment control
measures installed to prevent the material from leaving the site. Regardless
of the type of surface covering provided, runoff waters with erosive velocities
should be prevented from entering the area.
1. Vegetation
Establishment of vegetation to protect soil surfaces from
erosion and reduce the runoff of sediments can either be temporary or
permanent. Temporary vegetation should be used to provide control during
construction, or until permanent vegetation develops fully. Permanent
vegetation stabilizes the site following completion of the construction project.
Vegetative soil stabilization should be considered as being an integral part
of, and equal in rank to, mechanical structures for erosion and sediment
control. Prior to initiating grading operations, plans should be made to
preserve as much of the sites existing plant cover as possible. Many times
these areas can serve as filter strips or buffers to control sediment runoff.
Topsoil stripped from the ground surface should be stockpiled (and protected
from erosion) for future replacement on exposed ground prior to re vegetation.
Procedures for establishing vegetation are different in each
area of the U. S. (Reference No's. 1 through 16). They depend upon the climatic,
hydrologic, soil, slope, and other conditions in the specific area and the type
of plants to be used. In general, the site has to be prepared for the seeding
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or installation of plant stock. This involves protecting the surfaces
from erosive effects of rain and runoff, particularly concentrated runoff
on steep slopes, and preparing the seedbed. Soil additives such as lime
and fertilizers should be applied in accordance with needs as determined
by soil tests; recommendations provided by local conservation districts,
farm advisors, Extension Service, Universities, and landscape architects;
or data presented in erosion and sediment control guidebooks, handbooks,
or standards and specifications which cover the site area (Reference
No's 1 through 12, and 16 ).
Maintenance of established vegetative cover is particularly important
for effective control. Many "domesticated" types of vegetation, particularly
grasses and legumes, need considerable maintenance and can be forced
out by native vegetation if this maintenance is not regular. In many cases,
however, if it provides adequate ground cover and prevent erosion, native
vegetation may be found to be the more desirable product to use.
Figure 1 - Seeding of temporary, fast growing grasses often is most
desirable when final grading cannot be done until a later date.
(Reference No. 17).
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2. Mulches (organic residues)
Mulching consists of applying plant residues, or other
suitable protective materials to the surface of the soil. Organic residues
consist of plant residues, wheat or oat straw, hay, or other materials
such as wood chips, bark, sawdust, and the like. Production of mulch
materials from usable waste products generated during the construction
activities should be encouraged as these materials would otherwise have
to be disposed of elsewhere. Mulches can be used before, during, or
after seeding to aid in the establishment of a. vegetative cover or to
prevent erosion and runoff of sediments, reduce soil compaction and
surface crusting, conserve soil moisture, and minimize temperature
changes in ground surfaces. They can also be used without seeding
to temporarily protect exposed and erodible soils from erosion and sedi-
ment losses.
Quantities of mulch applied should be based upon the results
desired and the characteristics of the materials used. Smothering of
potential vegetation should be avoided but enough mulch used to prevent
erosion and loss of sediment from the area. Generally, it is applied
with power equipment such as "hydro-mulcher" and anchored to prevent
removal by water or wind. Anchoring is done by "tacking" with asphalt
emulsions, chemical mulcheSj cove ring with netting, using a serrated
straight disc to punch it into the soil surface, or some other means.
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Figure 2 - After seeding and fertilizing, the slope was mulche.l and
covered with netting (Reference No. 17).
3. Pervious Blankets, Nets and Similar Protective Materials
These materials are used to provide protective coverings
in critical areas which are extremely subject to erosive processes due to
erodible soils, steep slopes or concentrated runoff water. They include
excelsior blankets; fiber glass matting; fiber glass "angel hair" which is
dispensed and spread by compressed air; jute netting; and biodegradable
sheet paper products, with or without reinforcing for strength.
These products are generally used to provide temporary
protection of the underlying soils while a more permanent protective
cover of permanent vegetation is developing. As their cost is generally
A
higher than mulching, their use is most justifiable where steep slopes
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and erodible soils exist or where runoff water concentrates such as in
swales, waterways, ditches, and the like.
Application of the pervious blankets, nets, and other materials
will depend on the conditions in the area to be protected, characteristics
of the materials to be used, and future activities to be conducted at the site.
The manufacturers of these materials generally provide information appli-
cable for proper installation procedures; and they usually make technical
representatives available for consultation regarding problem conditions.
Being extremely flexible, pervious blankets and nets
generally conform well to irregularities in the ground and restrict movement
of runoff water. Some method of fastening these materials to the ground,
such as stapling, is usually required. When materials come in rolls,
overlap of adjacent materials is necessary. As a result, the direction
of water flow must be carefully considered prior to installation. In general,
blankets should be installed so that the up-slope layer overlaps the downslope
layer. In swales, or ditches, the material is generally unrolled from
the top of the channel in a downstream direction, with overlaps parallel
to the channel (Figure 3) . On steep cut or fill slopes, the material
is unrolled parallel to the contours with the upslope materials overlapping
the downslope layer. The upper ends of blankets and nets should be
installed in erosion checks to prevent movement of water beneath the
layer and subsequent erosion. Checks involve a technique whereby the
porous mat is installed into a slit trench excavated perpendicular to
the flow of runoff and then contained by backfill. (See Erosion Check,
Figure 14). Information on methods for use in utilizing various types of
flexible channel linings; including vegetation and riprap is presented in
Reference No. 30.
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Figure 3 - Jute netting being installed (Reference No. 15)
4. Chemicals
Chemicals used for surface soil protection generally function by
infiltrating the ground surfaces and binding particles of soils and other
foundation materials into a coherent mass that resists erosion and reduces
water evaportation losses. In addition, these chemicals maybe used as tack
material to bind organic mulch residues into a coherent protective blanket.
Chemical soil binders are used primarily to protect exposed
soils from wind and water erosion during delays in construction activities,
during hot and dry periods after final grading, or until permanent seeding
is possible. As tacks to bind mulch materials, chemicals are more rapid
curing than asphalts. This makes them particularly useful in land develop-
ment projects where tracking of sticky asphalt into homes can create problems.
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Many chemical soil binders can be applied with garden-type
hand sprayers, hydroseeders, or other types of equipment (Reference No.
15). They generally are mixed in a water solution and can be applied
with seed and fertilizer. Numerous dilution ratios and application rates
have been developed by manufacturers of these chemicals for use with
different soil types and textures. In general, the greater the percentage
of water, the deeper the penetration of the solution into the soil and the
weaker the binding strength. The soil characteristics must be evaluated
carefully to determine the proper dilution ratio to achieve adequate depth
of penetration of the material and effective binding strength.
According to their manufacturers, the chemicals used for
surface protection are nontoxic to humans and animals and generally
nonflammable. Additional information is needed, however, to determine
their toxicity with regard to fish and aquatic organisms. Technical repre-
sentatives from the manufacturing firms will provide consultation for
treating specific problem areas.
Controlling The Erosion and Transport Capacity of Runoff Water
Runoff water moves over denuded surfaces of construction sites as sheet
flow or as concentrated flow in rills and gulleys. It is dynamic in that it
has energy to erode as well as transport sediment particles. If the available
energy in the moving water is greater than that required to transport
the sediment it has entrained, erosion of the underlying material will
occur. If the sediment load is greater than the transport capacity under the
existing ^conditions, deposition will take place and continue until a balance
between ene,rgy available and sediment load is achieved. Controlling runoff
water, in 'constfruption areas is essential to prevent the generation and trans-
porj of sediments which can pollute downstream areas.
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Structures, with or without the use of vegetation, have been devised to
reduce or prevent excessive erosion and even to induce sediment deposition,
by preventing runoff water from reaching erosive or transport velocities.
They intercept, divert, and dissipate the energy of runoff; reduce hydraulic
gradients; prevent concentration of flows; retard and filter runoff; and
contain concentrated flows in nonerodible channels.
Structural measures used to accomplish these tasks include diversion
structures such as dikes and ditches, waterways, level spreaders, downdrains,
check dams or flow barriers, filter berms, and inlets; and grade stabilization
structures. These measures can be temporary or permanent. Temporary
control measures are used to correct detrimental conditions in a site
area that develop during construction operations; were not predicted during
project design, or are needed to control erosion and sediment that become
problems during construction but are not associated with permanent
measures. Permanent measures are intended to remain in place during
the life of the project facilities.
A formal design is generally required only for permanent erosion and
sediment control structures. The expected life of the structures, the
estimated maintenance requirements, the potential hazard from failure,
and other factors should be used to determine the design of erosion and
sediment control structures. Rainfall and runoff frequencies, are important
when analyzing the size and desired control characteristics of both temporary
and permanent structures. Minimum capacity for structures should be
that required to control the peak runoff calculated to result from the
selected design storm. For example, a 100 year frequency storm would
not be considered appropriate for the design of a temporary measure intended
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for use only during the short construction life of a small project. This
would be "over designing" and impractical.
1. Dikes, or Berms, and Ditches - Dikes and berms are different
terms used for diversion structures, linear ridges built of compacted earth
or other materials. They may be temporary or permanent. Ditches
and dikes are used conjunctively with one another, or independently, to
intercept and direct runoff, to prevent the concentration of water, reduce
slope lengths so that runoff velocities are reduced, and move water to
stable outlets at nonerosive velocities (See Figures 4 and 5). As the length
of a slope increases, the quantity and velocity of runoff water it collects
increases. The effects of these factors on erosion of materials on the
slope can be controlled through the use of dikes, berms, and ditches
which break up the intensity of the slopes.
The number of structures needed on any construction project
and their size and spacing depend on the land slope, soil types, and
runnoff rate. Runoff from the areas immediately upslope from the project
site must be considered in their design. They should have sufficient
capacity to convey, or store, the peak runoff to be expected from a storm
Area graded for development
Channel to divert water away
from construction site
Figure 4 - Diversions should also be constructed across graded areas to
shorten slopes and reduce erosion on the sloping areas.
(Reference No. 2)
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Figure 5 - Small Diversions. If both lip and bed are constructed at zero
grade, these diversions would be level spreaders. (Reference No. 18)
frequency consistent with the hazard deemed acceptable by the control
agency. Most organizations involved with sediment control require these
type of structures to be designed for the peak flow to be expected from
a storm of at least a 10 year frequency and 24 hour duration (See References).
Where structures are to be permanent, and schools, dwellings, or commercial
buildings, etc. are to be protected, the storm frequency period often is
lengthened consistent with the hazards from overtopping or structural failure.
Similarly, if the structures are temporary, with an extremely short expected,
life a shorter frequency may be considered practical for design purposes.
All structures composed of erodible materials should be protected
by establishing a vegetative or other type of cover; and maintenance should be
conducted periodically to ensure that they perform up to design capacities
and are not damaged. This may involve removing sediment accumulations.
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repairing eroded or overtopped sections, or even revegetating where needed.
2. Level Spreaders - Level spreaders are outlet structures provided
at the downstream end of diversions to dispose of concentrated runoff
as sheet flow at non-erosive velocities into stabilized areas (See Figure
No. 6). They are constructed on undisturbed ground and where the
area directly downslope from the horizontal discharge lip is stabilized by
existing vegetation. Water must not be permitted to concentrate below the
discharge area.
Undisturbed Soil
Stabilized by
Existing Vegetation
" .1 Tur jf\
2:1 or Flatter
I B' I
k_njl.-n »l
Note: Drawing not to scale
Figure 7 - Level Spreader (Reference No. 15).
Most authorities do not specify formal design, however,
they suggest the spreader length be determined in accordance with the
estimated discharge from a 10 year storm. The following table presents
information for selecting appropriate spreader lengths.
DESIGNED Q
(CFS)
Up to IO
1O to 20
2O to 3O
30 to 40
40 to SO
MINIMUM LENGTH
("L" IN FEET)
15
20
26
36
44
TABLE 1 (From Reference No. 1)
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3. Downdrains - Downdrains can be of the flexible, or rigid, sectional
type (Figures 7 and 8). They are used to convey storm runoff from the top
Figure 7. Temporary, flexible slope drain. Discharges on gravel energy
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Figure 8 - Sectional Downdrain (Reference No. 18).
of a slope to the bottom without causing erosion. Flexible downdrains, con-
sisting of conduits of heavy-duty fabric or other materials, may be used as
temporary or interim structures to prevent erosion of slopes. Sectional
units also may be for temporary use. They are prefabricated half-round,
or third-round pipe, corrugated metal, concrete, asbestos cement, and
other materials.
Formal design is generally not needed for these temporary
structures, however, they should have sufficient capacity to convey the
maximum quantity of runoff expected during their period of use.
Care must be taken that discharges from these types of structures
do not create additional erosion problems at their downslope ends. Generally
some type of energy dissipator will be required such as riprap, rock rubble
mound, or even a designed structure. The disposal area downstream from the
energy dissipator should be well protected and the surface soil stabilized
by vegetative cover.
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4. Chutes and Flumes - These structures are rigid channels
constructed of concrete, asphalt, or comparable materials and used to
conduct runoff downslope from one elevation to another without causing
erosion. They can be installed as temporary or permanent structures
(See Figure 9 and Reference Nos. 2, 15, and 17).
Figure 9 - Temporary flume made of concrete (Reference No. 14).
Chutes and flumes should not be used on slopes steeper than
1. 5:1 (34 degrees) or flatter than 20:1 (3 degrees). The underlying foundation
must be either firm undisturbed material or well-compacted fill. The rigid
lining should be fairly dense, free of voids, and relatively smooth surfaced.
Design criteria for areas in the eastern U. S. are presented in References
No. 1 and 7 for information purposes. Essentially they divide the structures
into two groups, based upon dike height at the structure's entrance, the depth
of flow down the chute, and the length of inlet and outlet sections as follows:
Size Group A
1. The height of the dike at the entrance (H) equals 1. 5 feet.
2. The depth of flow down the chute (d) equals 8 inches.
3. The length of the inlet and outlet sections (L) equals 5 feet.
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Size Group B
1. The height of the dike at the entrance (H) equals 2 feet.
2. The depth of flow down the chute (d) equals 10 inches.
3. The length of the inlet and outlet sections (L) equals 6 feet.
Each size group has various bottom widths and allowable drainage
areas as shown on the following table:
Bottom Maximum Bottom Maximum
Width, b, Drainage Area Width, b, Drainage Area
Size I/ ft. acres Size I/ ft. acres
A -2
A -4
A -6
A -8
A -10
2
4
6
8
10
5
8
11
14
18
B-4
B-6
B-8
B-10
B-12
4
6
8
10
12
14
20
25
31
36
!_/ The size is designated with a letter and a number, such as A-6 which
means a chute or flume in Size Group A with a 6-foot bottom width.
If a minimum of 75% of the drainage area will have a good grass or wood-
land cover throughout the life of the structure, the drainage areas listed
above may be increased by 50%. If a minimum of 75% of the drainage area
will have a good mulch cover throughout the life of the structure, the
drainage a-reas listed above may be increased by 25%.
These structures in all areas of the country should be designed
based upon runoff flows to be expected at the frequency inteval selected.
Care must be exercised in their construction, as well as their design, as
overtopping by flows, differential settlement of foundation materials, or
opening of construction joints may cause failure.
As in downdrains, chutes and flumes will require some sort
of energy-dissipating device incorporated into their lower, or outlet,
section at the bottom of the slope being protected.
5. Waterways or Outlets These structures are wide, shallow
natural or constructed channels which are shaped, graded, and vegetated
for the purpose of conveying and disposing of excess runoff without causing
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erosion or flooding (See Figure No. 10). Many authorites design them to
accomodate the expected runoff from a storm of selected frequency (generally
a 10 year frequency, 24 hour duration storm) without damaging the channel
or its lining (References 1, 2, 5 and 7). Design may include structural
measures to keep runoff velocities below erosive limits, protective
vegetative coverings, or some type of lining, to prevent erosion. The
success of a waterway depends upon it having a stabilized outlet area.
If this has not been provided, failure could occur, with erosion progressing,
in a headward direction up the waterway.
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Figure 11 - Jute Netting Over Straw Mulch in Waterway (Reference No. 15).
6. Grade Stabilization Structures - These structures are provided
to reduce the slope of natural or artificial channels. They prevent concen-
trated runoff from reaching excessive (erosive) velocities and prevent
headward erosion (upward advance) of channels. Generally, they are permanent
and expensive structures and should be used only where vegetative, diversion,
or other types of measures cannot prevent concentrated water from reaching
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high enough velocities to cause erosion. Grade control structures include
check dams, drop structures, and erosion stops.
A. Check dams generally also provide partially-lined channel
sections and overfall structures of concrete, wood, rock, and other
materials. They protect channel surfaces and reduce flow velocities
below that required to erode (See Figure No. 11). They should be situated
in a fairly straight section of a channel, after careful consideration of site
conditions. Generally, a formal design is required.
Figure 11 - Rock Check Dams (Reference No. 18).
B. Drop, or overfall, structures are made of rock, concrete,
metal or treated wood while pipe-drop facilities are usually constructed
of metal or pre-cast material (See Figures 12 and 13). Suitable iniet and
outlet facilities are normally required for each structure unless foundation
conditions dictate otherwise; and channel protection, through linings or
other means, is essential.
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Figure 12 - Box Inlet Grade Control Structure (After Reference No. 13).
Figure 13 - Drop Box Structure Combined With Culvert (After Reference No. 13).
C. Erosion checks, or stops, are measures used to prevent
channel erosion through the installation of non-erodible materials, into a
trench oriented normal to the flow of water (See Figure 14). They can be
installed in channels and swales or on extremely erodible slopes. Depths
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should be below the estimated depth of possible erosion or, to 12 inches.
The check should extend laterally above water surface expected from
design storms for the facility being protected.
1. Cutaway of fiber glass Installation In bottom of trench.
2. Cutaway of fiber glass installation in trench with spoil pile.
3. Vrfr.Kih with fiber glass erosion check installed.
4. Cap atrip of blanketing material over completed erosion check.
Figure 14 - Erosion check (Reference No. 15).
Trapping Sediments
Structures used to trap sediments are developed principally to stop the
movement of materials being transported by runoff water and prevent
them from leaving the site area. They consist of filter berms, sandbag
or straw-bale barriers, filter inlets, culvert risers, sediment detention
basins, and similar facilities. Many other structures and vegetative
measures also act, to a limited extent, as partial sediment traps; however,
this is generally not their principal function.
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1. Filter Berms - Filter berms usually consist of pervious
barriers composed of gravel, crushed rock, or similar materials. They
temporarily detain runoff water to allow sediment to deposit and act as a
filters, permitting water to move through them but not the sediment being
transported (See Figure 15). Formal design is not required but pervious
gravelly materials must be sized so that sediments do not pass through the
berm too readily.
Figure 15. Filter berm (Reference No. 18)
2. Sandbag or Straw-Bale Barriers - These temporary structures
may be used independently as control structures or in conjunction with filter
berms. They can act as diversion or detention facilities and used to protect other
structures, such as inlets from sediment, laden flows. Water passes through
straw bales as well as the sand and gravel filter-berm spillways, but the sedimen
is retained (See Figure 16 and 17).
They are used to detain sediments resulting from small drainage
areas in the order of 1/2 acre in size. The bales must be securely staked and
preferably bound with wire rather than twine. Water must not be allowed to
escape freely under the bales.
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3-24
Gutter
,Storm sewer structure
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Anchor with two stakes
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Figure 11 - Temporary Barrier of Hay Bales to Prevent Sediment-Laden
Water From Entering Storm Sewer (Reference No. 17).
3. Culvert Risers - Culvert risers are upward-extending, often
perforated pipes forming the intake area of culverts. Their purpose is to
pond runoff water temporarily and enable its sediment load to settle
out. Gravel filters may be used around perforated pipe sections. Their
function and design are similar to that for sediment basin outlet works
(principal spillways).
4. Sediment Detention Basins - A sediment detention basin (sometimes
referred to as a debris basin) probably can be considered as the "last line
of defense" in a system of Best Management Practices developed to prevent
runoff of sediments from a construction site. Probably the most expensive
and precisely-designed structures used for sediment control purposes,
they may be installed as temporary structures or as permanent facilities
used to provide storage of water for aesthetic and other useful purposes.
The design used must reflect the intended use of a detention basin.
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3-25
Sediment detention basins usually consist of small compacted
earth-fill dams, reservoirs which may be partly excavated to provide em-
bankment materials, uncontrolled outlet pipe (or spillways) and emergency
spillways (See Reference Nos. 14 and 15). This latter spillway is usually
cut into undisturbed materials around the end of the embankment. It is
unlined but vegetated to prevent erosion. Sometimes a lined over-pour
spillway is used over the top of a small dam embankment. The lining of
this latter spillway must be well-designed to prevent lining failure and a
possible dam failure also.
'&3K^^
Figure 18 - Large, Well-Engineered Sediment Basin Dam. Note Principal
Spillway Pipe with Riser, Gravel Core Filter, and Seepage-path
Cut-off Collars on Outlet (Reference No. 17).
Most existing sediment control guidelines, handbooks, and other
such documents require that detention basins be designed to store 0. 5 inches
of water from the watershed (67 cubic yards/acre) and that they be cleaned
out when storage is decreased, by sediment deposits, to 0. 2 watershed inches
(27 cubic yards/acre) as measured to the crest of the emergency spillway,
or pipe spillway crest if there is no emergency structure. (Reference No's.
2, 4, 7 and 15). In addition, they provide for principal (pipe) spillways to
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3-26
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Figure 19 - Sediment retention structure - small, less than 1/4 acre
(Reference No. 15).
handle at least 5 inches of runoff from the drainage area in 24 hours and
emergency spillways to pass the peak runoff from a 10 year 24 hour storm
(less reduction in flow due to pipe spillway). Drainages more than 20 acres
in size generally are designed for a 25 year frequency storm. Maximum
allowable flow velocity in vegetated unlined emergency spillway channels
is 6 feet per second (See Table 1). These design concepts are based on
"rule of thumb" storage capacity for sediments and dam safety. They
certainly are important factors, and must be considered in the design;
however, they do not fully result in the achievement of adequate sediment
detention.
Since the main purpose of a sediment detention basin is to
temporarily detain, or store, runoff water long enough for sediment
particles which are being transported to settle out at their natural settling
rate, this must be the principal factor in the design. Fine-grained materials
such as silts and clays, which settle out at extremely slow velocities, are
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3-27
extremely difficult to trap in most of the presently-de signed basins. As
a result, considerable effort must be made to design the facilities to trap
materials of these sizes. If it cannot be done, flocculation or some other
technique may be required. Flocculation involves causing the aggregation of
these fine-grained materials through the use of chemical or other materials.
In order to trap sediments of a certain size, a detention basin
must detain runoff water long enough for these materials to settle to the
bottom of the basin naturally. Table 2 gives settling velocities for various
sediment sizes. A detention reservoir should be large enough (in area).
TABLE 2 (From Reference No. 20)
Settling Velocities of Selected Particles
Kind of Material
Coarse sand
Coarse sand
Fine sand
Fine sand
Fine sand
Silt
Coarse clay
Fine clay
Particle Diameter (microns) Settling Velocity (cm/sec)
1000 10.0
200 2.1
100 0.8
60 0.38
40 0.21
10 0.015
1 0.00015
0.1 0.0000015
to enable sediment-laden inflow water to be diffused and dispersed so that it
must move vertically to gain access to the outlet. Design of this outlet is
critical and perforated, easily accessible structures such as that shown in
Figure 18 are not desirable unless sediment is extremely coarse-grained.
This design facilitates "short circuiting" of the flow path and enables currents
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3-28
to transport sediment loads directly through the reservoir and into the
outlet facilities without dispersion.
The area of the detention reservoir and its depth are the
critical factors for design purposes. Increases in the surface area of a
correctly designed reservoir will result in decreases in the velocity of the
sediment-laden water as it moves upward and into the pipe outlet, or spillway
(See Figure 20, and Reference No. 20). The area required to trap each
size sediment particle can be determined by the following formula:
A (area in square feet) = Q (pond outflow rate, in cubic feet per second)
V(upflow velocity, in cubic feet per second)
u
If the settling velocity of a particle of given size (V) is greater
s
than V, the velocity of the upward-flowing water, deposition of all particles
u
of this size and larger will settle to the bottom and be trapped. Smaller-sized
materials will pass through the outlet and spillway and escape. Table 3 presents
minimum reservoir surface area required to trap various sediment sizes.
TABLE 3
Minimum Area for Sediment Detention Basin
To Trap Sediment Particles (1 cubic foot/second outflow)
Kind of
Material
Coarse sand
Coarse sand
Fine sand
Fine sand
Fine sand
Silt
Coarse clay
Fine clay
Particle
Diameter
(microns )
1, 000 (1mm)
200
100
60
40
10
1
0.1
Minimum Area
Required
(sq ft)
3.0
14.5
38.2
80.0
145.0
2,030.0
203, 000. 0 (4.
20,300,000.0 (46
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Figure 20 - Theoretical Movement of Sediment Through Properly Designed Basin
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3-30
Depth of the reservoir is important to provide storage for
adequate quantities of sediment and still maintain dispersion of inflow and
upward movement into discharge facilities. Detention time should be
determined at the point that sediment storage has reached its maximum and
no "short circuiting" has occurred. In this way the reservoir is designed
for maximum efficiency. Periodic sediment removal will maintain this
storage volume and is required for good operations. Sediments should not
be disposed of in an area where they will create additional pollution problems.
The shape of the reservoir and design of its headwater, or
inlet, area are important in preventing short circuiting of flows. If con-
centrated, high-velocity currents enter the reservoir without being dispersed
and their velocities decreased, they will not only continue transporting
their sediment loads through to the outlet areas but may stir up and erode
deposits that had already been trapped on the reservoir bottom. Multiple
inlets, level spreaders or weirs of some type, and even baffles may be
devised for use in dispersing the inflow and reducing its velocities.
Principal outlets, or spillways, are also important for good
sediment trapping efficiences. Multiple spillway intakes, trough-type
outlets, or even syphon-type structures will prevent concentration of flow
and the accompanying high velocities which may again place sediment back
into transport. A standpipe full of perforations such as that in Figure 18
is a poorly-de signed facility because it results in short circuiting. Unless
the gravel envelope is a well-graded filter, sediment will be able to move
through it easily and downstream. If the envelope is clogged, concentration
of flow into the remaining section may occur causing bottom scour and
additional sediment entrainment and loss.
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For outflow rates above one cubic foot per second, the minimum area
shown in Table 3 must be increased equivalently. For example, in
order to trap a coarse sand with a particle size of 200 microns, and
an outflow rate of 3 cubic feet per second, the reservoir area should be
14. 5 square feet x 3 cfs = 43. 5 square feet (See Table 3).
Additional guidance for design, construction, and maintenance
of sediment basins is presented in references listed at the end of this
chapter. It involves principally factors for structural safety, good con-
struction practices, and location and capacity of overflow structures,
not sediment detention capacity. In many states, the larger-sized sediment
detention dams and reservoirs may fall within the jurisdiction of a dam
safety organization. These organizations have mandatory criteria for
minimum spillway capacity, design and construction procedures, seismic
coefficients, and the like.
Good Housekeeping Practices
Good erosion and sediment control, in conjunction with management of
stormwater runoff, will prevent the movement of many pollutants other than
sediments. Those pollutants that are in solution; however, or are carried on
fine-grained sediments, may pass through all sediment control measures and
reach downstream water bodies. Materials, such as pesticides, petro-
chemicals, and fertilizers are nearly impossible to control once they
are present in the runoff water. The only practical control options available
are either to provide expensive water treatment facilities on stormwater
detention basins or to prevent these pollutants from reaching runoff waters
through the use of "best housekeeping practices".
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Pesticides
Use of many insecticides, herbicides, and rodenticides is restricted
by Federal, State, or local regulations. In order to limit the possibility of
these materials creating detrimental environmental effects as a result of
construction activities, strict adherence to recommended practices is
required. Application rates should conform to registered label directions,
and application equipment cleaned after use, or properly disposed of
(Reference No's. 21, 22, and 23). All pesticides are listed in issues of
the "EPA Compendium of Registered Pesticides", which can be obtained
from the Superintendant of Documents, U. S. Government Printing Office.
This document provides information on dosage and application rates,
tolerances, formulations, use limitations, and the pests controlled.
Supplements to the Compendium are issued periodically. Similar data
can be obtained from each State's Cooperative Extension Service.
Pesticide storage areas should be protected from the weather and from
public contact. Areas that have been recently treated with particularly
potent pesticides should be clearly marked to warn trespassers or unwary
persons.
Time of pesticide application is of particular importance in preventing
runoff of pesticides from the site area as pesticide losses occur principally
when high-intensity rainfall occurs shortly after application. Often, more
pesticide quantity is contained in solution in runoff water than attached
to sediment particles because the volume of water that runs off is much
greater than the volume of sediment lost. The concentration of pesticide
carried by the sediments is much greater, however, and subsequent
pollutional impacts may occur when the sediments are deposited in the
bottom of a water body. (See Reference No. 24).
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Petrochemicals
Control of petrochemical runoff, such as oils, gasolines, and greases
involves mainly sediment control as these materials adhere to, or coat,
sediment particles. Additional measures include proper disposal of the
waste products, prevention of oil leaks, and proper maintenance of equip-
ment. Used oils and greases and rags and papers impregnated with this
material should be disposed of in proper receptables and kept out of contact
with rainfall or runoff water. Dumping of waste materials should be avoided
at all costs. When machinery is to be maintained, lubricated, or repaired
on site, it can be placed upon a pad of absorbent material to intercept and
contain leaks, spills, or small discharges. In no case should any of these
latter operations be conducted closely adjacent to a stream or water body.
Fertilizers
Inorganic nutrient pollution is derived principally from fertilizers used
to develop adequate vegetation on exposed ground surfaces. Effective
sediment control measures and stormwater management practices as well
as good vegetative cultivation practices are useful for controlling fertilizer
losses. Proper timing of fertilizer applications and provisions for working
these and other materials into the soils at the required depth will do
much to minimize runoff of pollutants. More efficient use of fertilizers
may be achieved, and loss of nutrients reduced, by applying the required
quantity in several rather than one application. Evaluating essential
fertilizer and other additive requirements from actual soil test in the site
area is essential to ensure that only optimum quantities are applied. This
alone should reduce the possibility of material losses.
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Solid Waste
The major mechanism for control of solid wastes such as residues
from trees and shrub generated during land clearing; wood and paper from
packaged supplies; and scrap metals, sanitary wastes, rubber, plastic,
glass fragments, and the like resulting from normal day-to-day operations
is the provision of adequate and effective disposal facilities. These wastes
should be removed from the site frequently and transported to authorized
and suitable disposal sites. Recycling useful materials is a very important
procedure for control of potential pollutants and for recovery of needed
materials. For example, inert materials which do not leach and cause
groundwater problems may be used effectively to refill borrow pits or
other excavated areas. The same material can be considered for use
in road fills or fills for other facilities. Trees and other vegetation may
be chipped up and used on site areas as inexpensive and convenient mulch
materials. Any solid wastes trapped in sediment detention basins should
be removed as quickly as possible. Adherence to State and local anti-litter
ordinances should be enforced with regard to construction personnel, site
visitors, and others. If no violation of air pollution requirements is
involved, inflammable wastes may be burned. Reference Nos. 25 through
28 will provide information on air and solid waste requirements.
Storm Water Management
Storm water management involves controlling the rate of storm water
runoff from construction sites. It must consider control of storm water
during the life of facilities being constructed as well as during the construction
period itself.
In past periods, the philosophy for storm water control was to route it
through areas as quickly as possible. Under this concept, areas downstream
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3-35
from the sites had to accept the brunt of accelerated and increased peak
storm runoff. Flooding, excess channel erosion, and other damaging
effects resulted.
The present concept of storm water management is to reduce and
delay runoff water peak discharges. Management may be achieved by
increasing infiltration in the drainage area to reduce the amount of
precipitation that actually becomes runoff, increasing time of runoff
concentration by accentuating the meandering of drainageways to reduce
gradients and runoff velocities, and providing temporary storage facilities
to release the stored water at controlled rates.
Increasing Infiltration of Runoff
Methods used to increase infiltration of runoff into soils and other
subsurface materials have been used for a number of years in parking
areas. They involve periodic perforation of lawns, development of sub-
surface facilities, and the provision of porous pavement materials. Extreme
infiltration care must be used with regard to the quality of water being
infiltrated as it is possible to create a groundwater pollution problem
with the resolution of a surface water pollution problem.
Periodic perforation of golf course fairways has been used for quite
some time to increase infiltration and aeration. This same process will
help increase infiltration of storm water in vegetated areas of construction
sites. In addition to reducing runoff, the practice should accelerate move-
ment of fertilizers into the subsoil and provide for better vegetative growth.
Infiltration facilities may involve wells or excavations which have been
backfilled with pervious materials. Their purpose is to provide vertical,
highly-pervious conduits through which surface waters can gain access to
permeable subsurface strata. If these strata contain usable ground water
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3-36
supplies, the infiltrating water must not be poor enough in quality to degrade
them. These types of infiltration systems have been used in areas of suburban
development and along highways to accommodate excess runoff.
Porous pavements are used principally in parking areas of shopping
centers. They consist of irregularly-shaped aggregate precoated with
asphalt binder. Water can move vertically through this layer into an
underlying lower level of compacted gravels and then, if conditions are
favorable, into underlying natural foundation materials. Favorable
conditions are situations where existing ground water bodies will not
be degraded by infiltration of poor quality runoff. If ground water pollution
is possibly a problem, porous pavement facilities can still be used for
storm water management if designed properly. This design could involve
construction of a clay blanket or some other inpervious material below
the compacted gravel layer. Infiltrating water would then have to slowly
move laterally through the gravel and, after a delayed period of time, be
discharged into a storage basin where it can be treated and released.
Altering Time of Runoff Concentration
This aspect of storm water management should focus on the conservation
and use of existing natural drainageways. Conditions to avoid are long, narrow,
V-shaped channels with steep gradients, as they tend to promote concentration
of flow with accompanying high erosion hazard if the channels are not adequately
lined. The discharge end, where gradients decrease, can create severe
problems with respect to erosion if an effective energy-dissipation structure
is not provided.
To effectively decrease time of runoff concentration, wide, meandering,
vegetated channels with gentle gradients and side slopes are required.
Velocities in major channels of this type should be less than 5 feet per
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3-37
second with side slopes of less than 3 to 1. Curves, or bends should be
gentle with radii not less than 100 feet {Reference No. 29). Increasing the
time of concentration by reducing the runoff velocities in channels also acts
to increase infiltration as the runoff has longer contact with the ground
surface. Small check dams can be placed in the vegetated drainage
channels, or swales, to reduce runoff velocities, provide short-term
minor storage, and increase infiltration.
Providing Temporary Surface Storage
Almost all measures used to prevent erosion and sediment losses on
construction sites also function to control the runoff of storm water. Probably
the principal storm water management technique available, however, involves
temporarily storing surface water runoff and releasing it at a predetermined
decreased rate. Consideration of the runoff characteristics in the entire
basin must be made as improper releases of stored water could cause
increased rather than decreased flows in downstream areas. In addition,
in some channels, moderate downstream flows maintained for longer
periods of time may cause more problems than the peak flows themselves.
Storage can be provided on rooftops and in subsurface holding structures
or temporary or permanent surface impoundments. These surface im-
poundments may be in or near drainageways or even constructed in parking
lots or other facilities.
Rooftop storage can be achieved on relatively flat roofs by limiting
the release of precipitation which falls on the roof. Control is through
specially-constructed roof drains which cause the water to be ponded to
a particular level and release it at a reduced rate (See Figure 21). Flow from
the roof occurs through small holes or slots in the drains. Water released
should be spread, if possible over vegetated areas, to provide for infiltration.
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SCUPPER*
1 .*/ 9 ': »,-' '. « .'_ -7T
r.i : =*
ORAI
US' *-0* IEADE*
Figure 21 - Typical Roof System Illustrating Controlled
Release Roof Drain and Overflow Scupper (After Refernce 24).
Most buildings will structurally support a water load of approximately
3 inches, however, water-proofing techniques may have to be up-graded
to prevent leakage.
Subsurface storage of storm water runoff can be obtained in metal or
concrete tanks placed below ground level. Their inflow capacity to accept
runoff flows is designed to be much greater than their capacity to release
water, as a result, they provide temporary storage. Subsurface storage
facilities generally are used in expensive developments, such as shopping
centers, where there may be little available area for surface storage.
Intake and outlet structures and devices should be provided with screens
and have easy access for maintenance to prevent clogging.
Surface impoundments can be designed to provide for permanent or
temporary reservoirs which contain water only during periods of excess
runoff. Permanent impoundments provide an aesthetically- pleasing urban
environment as well as flood-detention storage for attenuating peak runoff
flows. The creation of permanent water storage areas, the "blue-green"
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3-39
devslopment concept, can be highly beneficial to a community. They
are generally developed through the construction of a small dam, with
necessary appurtenant structures such as spillway, outlets, and the like,
across a drainageway. The permanent water level of such reservoirs
is designed to be several feet below emergency spillway crest. Reservoir
volume above this elevation accommodates flood storage to attenuate
peak runoff flows. An outlet with a valve should be provided to facilitate
reservoir drainage when repair or maintenance of the structure is required.
Temporary reservoir storage in "dry" impoundments stores water only
during flood events. They are dry during the remainder of the time. These
reservoirs are created by some type of permanent water-detaining
structure or embankment. Outlet facilities, however, are ungated (no valve).
As a result, runoff which enters the reservoir at a high rate is immediately
free to discharge at a pre-designed lesser rate. This reduces peak runoff
to prevent or reduce downstream flooding, channel erosion, and other problems,
Since the same quantity of water must be released, longer periods of moderate
flows will occur in downstream channels. Dry impoundments, or reservoirs,
can be developed in any area that is topographically depressed, whether due
to natural or man-made conditions. Parking lots, tennis courts, playgrounds,
and other areas can be used to provide temporary storage facilities for
runoff if adequate outlet facilities can be installed. (See Figure No. 22).
Figure 22 - Storm Water Detention Storage Structure in Lower Portion
of Parking Lot (Reference No. 14).
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3-40
Off-stream impoundment of storm water runoff may be created adjacent
to existing stream channels or drainageways. A diversion embankment is
often used to divert water into a selected area during high flows. When
flood-levels decrease, the diverted water drains back into the main channel
at a decreased rate. Use of side-channel storage areas in flood plain
areas often is an inexpensive way of achieving effective storm water control.
Systems Approach to Sediment Control
Rarely will single erosion or sediment control measures be effective
enough to achieve desired results. Generally, several different measures
are provided as first, second, third, and even more "lines of defense".
This is termed the "systems approach" to sediment control. For example,
on a construction site, the area of exposed soils may be limited. Then
vegetation may be required on all areas which are left exposed more
than a certain length of time. In addition, various structures may be
required to protect the ground surface from rain and runoff water, control
the energy in runoff, and filter or trap sediments being transported. All
of these measures are included within the total system which is devised
to prevent loss of sediments from the site area.
The lack of reliable effectiveness factors hampers the optimization of
erosion and sediment control systems development. The effectiveness of
some individual measures in these systems may be found in published
literature, however, information on the various combinations in the system
is limited. In addition, most effectiveness factors have been developed
for agricultural practices and should not be assumed to be equivalent to
those used on construction sites.
A method to determine the effectiveness of a system of control measures
has been obtained from References 18 and 31, "Comparative Costs of Erosion
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and Sediment Control, Construction Activities", and "An Economic Analysis
of Erosion and Sediment Control Methods for Watersheds Undergoing Urban-
isation . , This method involves a comparison of the soil losses from a
construction site without control measures with that from a site with measures
installed. All other factors in the site area remain the same.
The various individual measures are viewed as cropping-management
i(C) and conservation practices (P)'factors for reducing soil losses. Thus,
tire soil loss (A1) from a given construction site having erosion and sediment
control treatments can be computed by the universal soil loss equation:
A1 = RLSKCP a)
If the same construction site was denuded and employed no erosion and
sediment control treatments, the soil loss (A") would be:
A" = RLSK (2)
since the factor C and P_ values equal 1.0. Values for RLSK are equivalent
in Equations (1) and (2) since the same construction site is used for both
equations. The soil retained on the construction site, because erosion
and sediment control treatments were employed, is computed by:
soil retained = A" - A1 (3)
Therefore, the effectiveness percent of the treatments in retaining soil
on the construction site is:
% Effectiveness = A" - A1 x 100
2T1"
= RLSK - RLSKCP x 100
RLSK
= (1 -JVCPjx 100 (4)
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3-42
Equation (4) can now be used to compute effectiveness for the various
erosion and sediment control alternatives, providing Factor C and P
values are assigned for the individual treatment comprising a particular
system.
Published Factor C (conservation) values need to be adjusted for
urbanizing areas because stabilized surfaces are disturbed by construction
traffic. Two assumed construction conditions have been considered:
(1) Construction is completed within 18 months following
initial groundbreaking.
(2) When building is started six months after seeding, then
construction is completed within 24 months.
It is further assumed that three months of the 18- or the 24- month
construction periods are consumed by grading operations, and that
construction sites are without surface protection during this time.
Factor C values change with time following surface treatment. For
example, Factor C values for grass decrease from 1. 0 to about 0. 01
between seeding and when the grass is reasonably well established. For
construction sites, Factor C values are assumed altered additionally
by urban development activities.
A typical example of estimating average Factor C value for seed,
fertilizer and straw mulch is as follows, after Reference No. 18:
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Fraction of
Representative Construction
Months
0-3*
3-6
6-18
Factor C Value
1.00
0.35
0.19
Period
3/18
3/18
12/18
Product
0.167
0.058
0.127
Average Factor C value for 18-month period = 0. 352
*During 0-3 months, Factor C value is 1.0 because the construction
area has no surface stabilizing treatment.
Table 4 lists the average values of Factor C for various surface
stabilizing treatments from (Reference No. 18) and Table 5 lists additional
erosion-reducing values for more specific ground cover.
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TABLE 4
AVERAGE FACTOR C VALUES FOR VARIOUS SURFACE
STABILIZING TREATMENTS ( REFERENCE NoTTsT"
Factor C Values for
Time Elapsed Between
Treatmemt
None*
Seeding and Buiidinj
b Months
Seed, fertilizer and straw mulch.
Straw disked or treated with asphalt or
chemical straw tack. 0.35
Seed and fertilizer 0. 64
Chemicals (providing 3 months protection) 0.89
Seed and fertilizer with chemicals
(providing 3 months protection) 0. 52
Chemical (providing 12 months protection) 0. 56
Seed and fertilizer with chemical
(12 months protection) 0.38
0.23
0. 54
0.38
* Assumes 18 month construction period.
** Assumes 24 month construction period.
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TABLE 5
EFFECTIVENESS OF'GROUND COVER ON ERC6ION LOSS
AT CONSTRUCTION SITES (REFERENCE NO. 18)
Soil Loss Reduction Related to
Bare Surfaces
Kinds of Ground Cover (Percent Effectiveness)
*Seedlings
Permanent Grasses 99
Ryegrass (Perennial) 95
Ryegrass (Annual) 90
Small Grain 95
Millet and Sudangrass 95
Field Bromegrass 97
Grass Sod 99
Hay (2 Tons per Ac) 98
Small Grain Straw (2 Tons per Ac) 98
Corn Residues (4 Tons per Ac) 98
Wood Chips (6 Tons per Ac) 94
** Wood Cellulose Fiber (2-3/4 Tons per Ac) 90
** Fiberglass (1, 000 Lbs per Ac) 95
Asphalt Emulsion (125 Gal per Ac) 98
*_-
* Based on full established stand
** Experimental - not fully validated
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Structures used in the various control systems are considered as requiring
Factor P values to describe their efficiency (Reference No.. 31). These components
include small sediment basins, erosion reducing structures, and downstream
sediment basins with or without the use of chemical flocculants. Diversion
structures, grade stabilization measures and level spreaders are collectively
considered as erosion reducing structures. The practice factor P reflects the
runoff and erosion-reducing effects of structures. The effectiveness of terraces
and diversions, which reduce effective slope lengths and runoff concentration
should be similar on construction sites and farmlands (See Reference No. 32).
Small Sediment Basins - The conventional method employs small sediment
basins having inflow (cubic feet per second) to area (square feet) ratios of
0. 03 to 0. 04, with an average trap efficiency of 70 percent. Thus, if the
sediment basin collects sediments coming from only 70 percent of the
construction area then its Factor P value is about (1. 00 - 70%) x 70% = 0. 50.
On the other hand, if it collects sediments from 100 percent of the construction
area then its Factor P value is (1. 00 - 70%) x 100% = 0. 30 (See Table 6).
Downstream Sediment Basins - The larger size basin constructed down-
stream of the construction site, and having inflow to area ratios of 0.06
to 0. 07, will have a trap efficiency of 80 percent, thus the corresponding
Factor P value is 0.20. Chemical flocculants may be added to this downstream
basin to cause more efficient settling of incoming sediment. Such chemicals
are assumed to increase the trap efficiency of this basin 90 percent, giving
a Factor P value of 0.10.
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Erosion-Reducing Structures - Diversion berms, sodded ditches, inter-
ceptor berms, grade stabilization structures and level spreaders are
collectively referred to as one system called "erosion-reducing structures".
The overall effectiveness of erosion reducing structures is estimated at
50 percent. The Factor P value for this normal usage is then 0. 50. For
higher usage, the erosion reducing structures are estimated to be 60 percent
effective, giving a Factor P value of 0. 40 for this case.
Factor P values for these systems are summarized in Table 6 and
discussed below.
In using these Factor P values to estimate effectiveness of the erosion
and sediment control alternatives, it is assumed that 100 percent of the
sediment not caught by the surface stabilization treatments and/or erosion
reducing structures is delivered to the sediment basins.
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TABLE 6
FACTOR P VALUES FOR.COMPONENTS OF
EROSION AND SEDIMENT CONTROL SYSTEMS (REFERENCE NO'S 18 and 31)
Factor
Component Value
Small sediment basin: (0.04 ratio)
Sediment from 70% construction area 0. 50
Sediment from 100% construction area 0. 30
Downstream sediment basin: (0. 06 ratio)
With chemical flocculants 0.10
Without chemical flocculants 0.20
Erosion reducing structures:
Normal rate usage (165 ft per ac) 0. 50
High rate usage (over 165 ft per ac) 0.40
The effectiveness of various erosion and sediment control systems is
computed and listed in Table 7, using the equation:
Percent Effectiveness = (1-CP) x 100
Factors C and P are taken from Tables 4 and 6, respectively.
Factor P values are multiplied if a particular erosion and sediment control
alternative has two or more components represented by a Factor P. An
example of this calculation is shown using the conventional method of erosion
and sediment control.
~~ Factor C or P
Conventional Method Value
Sediment basin (. 04) 0. 50
Erosion reducing structures (normal) 0. 50
Seed, fertilizer and straw mulch 0. 35
Percent Effectiveness = 1-(0. 35 x 0.50) x 100 = 91.25 percent.
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TABLE 7
PROMISING CONTROL SYSTEM AND EFFECTIVENESS
{AFTER REFERENCE NO. 13)
System: Numbers Components Percent Effectiveness"
1 Seed, fertilizer, straw mulch. 91
Erosion structures (normal). Sediment
basins (0. 04 ratio, and 70 percent of
area)
2 Same as (1) except chemical (12 months 90
protection) replaces straw.
3 Same as (1) except chemical straw tack 91
replaces asphalt.
4 Seed, fertilizer, straw mulch. Diversion 90
berms. Sediment basins (0.04 ratio, and
100 percent area)
5 Seed, fertilizer, straw mulch. Downstream 93
sediment basin (0. 06 ratio).
6 Seed, fertilizer, chemical (12 months 92
protection). Downstream sediment basin
(0.06 ratio).
7 Seed, fertilizer, straw mulch. Downstream 96
sediment basin using flocculants.
8 Same as (7) without straw mulch. 94
9 Chemical (12 months protection) sediment 94
basin using flocculants.
10 Same as (9) with seed, fertilizer. 96
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Selected References
1. County of Fairfax, Virginia "Erosion - Sediment Control Handbook"
December, 1974.
2. U. S. Department of Agriculture, Soil Conservation Service "Guide for
Sediment Control on Construction Sites Ih North Carolina", March 1973.
3. Michigan, Department of Natural Resources ''Michigan Soil Erosion
and Sedimentation Control Guidebook", February 1975.
4. Virginia Soil and \Vater Conservation Commission "Virginia Erosion and
Sediment Control Handbook - Standards, Criteria, and Guidelines",
April 1974
5. Metro Association of Soil and Water Conservation Districts, Anoka,
Carver, Dakota. Hennepin, Scott and Washington Counties, Minnesota
"Urban Erosion Control Handbook", August 1973.
6. Knox Couty Soil Conservation District, Tennessee "Erosion and
Sediment Control Handbook", July 1973.
7. Maryland Department of Natural Resources, assisted by the U. S.
Department of Agriculture, Soil Conservation Service "Standards and
Specifications for Soil Erosion and Sediment Control in Urbanizing
Areas", November 1969.
8. California State Department of Public Works Division of Highways
"Erosion Control on California Highways", date unknown.
9. New Jersey State Soil Conservation Committee "Standards for Soil
Erosion and Sediment Control in New Jersey", June 1972.
10. University of Minnesota, Department of Horticultural Science, in
Cooperation With The Federal Highway Administration, Minnesota
Highway Department and Minnesota Local Road Research Board
"Development of Ground Covers For Highway Slopes" Final Report,
Investigation No. 615, May 1971.
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11. U. S. Department of Agriculture, Soil Conservation Service
"Handbook For Erosion and Sediment Control In Urbanizing Areas
In Hawaii11, March 1972.
12. Guidelines For the Control of Erosion and Sediment In
Urban Areas of The Northeast", August 1970.
13. "Engineering Field Manual For Conservation Products", 1969.
14. U. S. Environmental Protection Agency, Office of Air and Water
Programs "Processes, Procedures, and Methods to Control
Pollution From All Construction Activity" EPA-430/9-73-007, Oct. 1973.
15. , Office of Research and Monitoring "Guidelines For Erosion and
Sediment Control Planning and Implementation" EPA-R2-72-015, August 1972.
16. , Office of Water and Hazardous Materials, "Methods of Quickly
Vegetating Soils of Low Productivity, Construction Activities" EPA-
440/9-75-006, July 1975.
17. -, Office of Water Programs "Control of Sediments Resulting
From Highway Construction and Land Development", September 1971.
18. , Office of Water Program Operations "Comparative Cost of
Erosion and Sediment Control. Construction Activities", EPA-430/9-
73-016, July 1973.
19. U. S. Department of Transporation, Federal Highway Administration
"Prevention, Control and Abatement of Water Pollution Resulting From
Soil Erosion". Instructional Memorandum 20-3-70, April 1970.
20. American Public Works Association "Practices In Detention of Urban
Stormwater Runoff" Special Report 43 by H. G. Poertner, 1974.
21. U. S. Environmental Protection Agency, "Regulations for the Acceptance
of Certain Pesticides and Recommended Procedures for the Disposal and
Storage of Pesticides and Pesticide Containers" Federal Register Vol. 36,
May 23, 1973.
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Other References Used
Ada Soil Conservation District, Idaho, Assisted by the U. S. D. A.,
Soil Conservation Service and the Soil Conservation Commission, State
of Idaho "Sediment and Erosion Control Guide For The Boise Front -
Urban Area. Part 1 - General" June 1972.
American Association of State Highway and Transportation Officials
"Guidelines For Erosion and Sediment Control In Highway Construction"
1973.
American Association of State Highway Officials "A Guide for Highway
Landscape and Environmental Design", 1970.
Baltimore County, Maryland, assisted by U. S. D. A., Soil Conservation
Service "Sediment Control Manual", June 29, 1970.
Berks County Soil and Water Conservation District, Pennsylvania
"Handbook For Erosion and Sediment Control in Urbanizing Areas".
May 1970.
Georgia State, Soil and Water Conservation Committee, In cooperation
with U." S. Department of Agriculture, Soil Conservation Service
"Urban Erosion and Sediment, Damages, Planning For Solutions and
Steps to Effective Control". 1972.
Montgomery County, Maryland, Soil and Water Conservation District
"Erosion and Sediment Control Handbook". June 1970.
National Academy of Sciences, Highway Research Board "Erosion Control
on Highway Construction". 1973.
New Jersey State Soil Conservation Committee "Standards For Soil
Erosion,and Sediment Control In New Jersey", June 1972.
Pennsylvania Department of Environmental Resources, assisted by the
U.S. D. A., Soil Conservation Service "Soil Erosion and Sedimentation
Control Manual". January 1974.
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22. "Certification of Pesticide Applicators" Federal Register, Vol. 39,
No. 197, Part III, October 9, 1974.
23. Pesticide Programs "Registration, Reregistration, and Classification
Procedures "Federal Register, Vol. 40, No. 129, Part H, July 3, 1975.
24. and the Department of Agriculture, Agricultural Research Service.
"Control of Water Pollution From Cropland, Volume I", a manual for
Guideline Development, EPA-600/2-75-026a, November 1975.
25. "National Primary and Secondary Ambient Air Quality Standards"
Federal Register, Vol. 36, No. 84, April 30, 1971.
26. "Thermal Processing and Land Disposal of Solid Waste" Federal
Register, Vol. 39, No. 148, Aug. 14, 1974.
27. "Guidelines for The Storage and Collection of Residential,
Commercial, and Institutional Solid Waste", Federal Register, Vol. 41,
No. 31, Feb. 13, 1976.
28. "Source Separation For Materials Recovery Guidelines", Federal
Register, Vol. 41, No. 80, April 23, 1976.
29. U. S. Department of the Interior, Office of Water Resources Research
"Approaches to Stormwater Management", by Hiltman Associates, Inc.
Contract No. 14-31-001-9025, Nov. 1973.
30. U. S. Department of Transportation, Federal Highway Administration
"Design of Stable Channels with Flexible Linings" Hydraulic Engineering
Circular No. 15. October 1975.
31. U.S. Department of The Interior, Office of Water Resources Research
"An Economic Analysis of Erosion and Sediment Control Methods For
Watersheds Undergoing Urbanization" By Dow Chemical Corp. Final Report
for contract no. # 14-31-0001-3392. February 15, 1971 - February 14, 1972.
32. National Academy of Sciences, Highway Research Board "Soil Erodibility on
Construction areas", by W. H. Wischmeier and L. D. Meyer-Report 135, 1973
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U. S. Department of Agriculture, Soil Conservation Service
"Environmental Do's and Don'ts on Construction Sites "Miscellaneous
Publication 1291. December 1974.
U.S. Department of Agriculture, Soil Conservtion Service "Sediment
Pollution and Erosion Control Guide For New Jersey". 1970 (Revised
in 1971)
U. S. Department of Agriculture, Soil Conservation Service, Davis,
California "Guides For Erosion and Sediment Control". January 1975.
U. S. Department of Agriculture, Soil Conservation Service, Maryland
"Standards and Specifications for Soil Erosion and Sediment Control
In Developing Areas".
U. S. Department of Agriculture, Soil Conservation Service, Somerset,
New Jersey "Standards and Specifications for Soil Erosion and Sediment
Control In Urbanizing Areas". March 1971.
U. S. Department of Agriculture, Soil Conservation Service, West
Warwick, Rhode Island, "Rhode Island Erosion and Sediment Control
Handbook". 1972.
U. S. Department of Commerce, Bureau of Public Roads, "Design of
Roadside Drainage Channels". 1965.
U. S. Environmental Protection Agency, Alaska \Vater Laboratory
"Environmental Guidelines for Road Construction In Alaska". August
1971.
U. S. Department of Transporation, Federal Highway Administratiion
"Guidelines for Minimizing Possible Soil Erosion From Highway
Construction". Instructional Memorandum 20-1-71, January 29, 1971.
- - "Stable Channel Design" by J. M. Norman. Preliminary
Subject to Revision. May 1974.
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"Suggestions For Temporary Erosion and Siltation Control
Measures", February 1973.
University of Minnesota, Department of Horticultural Science,
In Cooperation With U. S. Department of Transporation, Minnesota
Highway Department, and Minnesota Local Road Research Board
"Turf Methods and Materials for Minnesota Highways "Investigation
No. 619, November 1972.
"Vegetation Maintenance Practices, Programs and Equipment
on Minnesota Highways", February 1969.
Virgin Islands Soil and Water Conservation District "Environmental
Protection Handbook", October 1971.
Washtenaw County Soil Conservation District, Michigan, Assisted by
U.S. D. A., Soil Conservation Service, "Standards and Specifications
for Soil Erosion and Sediment Control", January 1970.
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