:LEAI
WAN K,
ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF WATER PROGRAMS
CONTROL OF EROSION AND SEDIMENT DEPOSITION
FROM
CONSTRUCTION OF HIGHWAYS AND LAND DEVELOPMENT
-------
This report was prepared by Mr. Robert E. Thronson,
Hydrologist, Environmental Protection Agency
-------
CONTROL OF SEDIMENTS RESULTING FROM
HIGHWAY CONSTRUCTION AND LAND DEVELOPMENT
Environmental Protection Agency
Office of Water Programs
Division of Technical Support
Technical Assistance Branch
Rural Wastes Section
September, 1971
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20102 - Price 60 cents
-------
FOREWORD
Soils, with their attendant pesticides
and nutrients, become a liability to
water resources management and to the
water-using society, and a significant
loss to the landowner when stolen
from the lands by uncontrolled runoff.
13.
-------
CONTENTS
Pago
FOREWORD ii
INTRODUCTION 1
The Problem 1
Objectives and Scope 2
Acknowledgements 2
STT.TIARY AND CONCLUSIONS 3
CAUSES 0^ ACCELERATED EROSION 4
EFFECTS OF EXCESSIVE SEDIMENT LO^DS 11
TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES.. l1^
Planning 1°
Surface Protection of Exposed Soils 27
Control of Runoff Mater 33
Trapping of Sediments 35
ESTIMATED COST OF CONTROL 42
ADMINISTRATIVE CONTROL 45
REFERENCES AND SELECTED BIBLIOGRAPHY 47
Cover Photograph: Eight Feet of
Sediment Deposited in Debris
Basin in. One Month. Tyson's
Corner, Fairfax County, Virginia.
-------
INTRODUCTION
Sedimentation involves three basic processeserosion,
transportation and deposition. They are natural geologic
phenomena that have been in continuous operation for
millions of years. Through these processes rock particles,
dissolved minerals, and other matter are derived from
topographically higher areas and transported downslope
into river, ponds, lakes, and oceans where they are
deposited and provide the essentials for maintaining
life.
Continuity of natural sedimentation processes is essential
to maintain the normal regimen of river systems and coastal
areas and to support the life cycle of organisms living
in them. To upset the equilibrium is to cause undesirable
readjustments of the system as a whole and possible
damage to the existing environment. Man's land develon-
ment activities have initiated these severe and highly
undesirable readjustments in the natural sedimentation
cycle, particularly in local areas, by drastically
accelerating the erosion process. As a result of the
greatly increased erosion, deposition of excess quantities
of transported sediments occurs in downstream areas.
The Problem
Costs of correcting erosion and sediment deposition
problems resulting from highway construction and land
development activities often are unjustifiable transferred
to the taxpayer. They result when consequences of the
construction operations on downstream areas are not properly
considered. Costs of remedial measures to rectify the
damages incurred are borne by others than those benefit-
ting from the development.
Although accelerated erosion and excess deposition of
sediments resulting from construction activities have
caused pollution of water bodies in many parts of the
country, damaged homes and drainage systems, made treat-
ment of water supplies more costly, and adversely affected
aquatic life, very few localities have organized and
implemented effective control measures (1). It anoears
that technical capability is not the governing factor
but how this capability is applied, financed, and ad-
ministered.
-------
Obj ectives and Scope
The objectives of this study were to: (1) obtain an
understanding of the effects of man's land development
activities on natural erosion processes, (2) determine
measures that will effectively control erosion at con-
struction sites, and (3) estimate costs of achieving
effective control.
The scope involved a review of existing published and
unpublished literature on sedimentation problem areas;
control measures used and proposed by concerned agencies,
and the administrative approaches to control. Because
of time limitations, much of the data, particularly
regarding cost estimates, were obtained by telephone
from various Federal, State and local agencies, as well
as from private developers and consulting engineers.
Land development, for the purposed of this report,
includes principally single-family and multiple-housing
developments and the accompanying shopping-center com-
plexes. Little effort was directed toward obtaining
data on sedimentation resulting from construction of
dams, canals, thermal or atomic power plants, trans-
mission lines, railroads, or bridges.
Acknowledgments
Special acknowledgments are given to: Mr. R. C. Barnes
of the Soil Conservation Service who freely submitted
data and advice; Mr. Herbert Kelly, also of SCS, who
released photographs of areas affected by erosion and
sediment deposition and of control structures; Mr.
O. C. (Bill) Leaf of the California Division of Soil
Conservation who provided reports on erosion and sedi-
ment deposition and photographs and sketches of control
structures; Mr. Richard Howell, California Highway
Research Laboratory, who gave information on slope
stabilization experiments and provided contacts for
additional data; and Mr. W. L. Hottenstein, from the
Federal Highway Administration, who submitted references
and data on highway construction activities. Drafting
of erosion control structure sketches was done by Messrs
Robert Eggleston and James Ingram.
Editing was done by Messrs K. M. Mackenthun and W. C.
Shilling who also provided technical advice and comments,
-------
SUMMARY AND CONCLUSIONS
1. Man's land development activities have drastically
upset the natural and necessary geologic process
of sedimentation by greatly accelerating erosion.
Deposition of excess quantities of sediments pollutes
down stream waters and damages lands.
2. The cost of correcting the erosion and sediment pro-
blems resulting from land development often is un-
justifiably transferred to the taxpayer rather than
to those benefitting from the development.
3. The technical capability of controlling erosion and
sediment deposition is available. It involves pro-
tection of disturbed soil from the energy of falling
rain and flowing runoff water by installing pro-
tective covers/ controlling runoff/ and trapping
sediments in transport.
4. The cost of effective erosion and sediment control
probably is minimal.
5. The principal problem lies in achieving effective
administrative control and enforcement by con-
cerned agencies of erosion and sediment control
programs.
-------
CAUSES OF ACCELERATED EROSION
The principal influence land development activities have
on the natural erosion process results from the exposure
of disturbed soils to precipitation and storm runoff water.
Shaping of land for construction purposes alters the soil
cover in many ways, often detrimentally affecting the
drainage, runoff, and stream-flow. Protective vegetative
cover is removed, excavations are made and the removed
material stockpiled without cover, slopes are modified
by making steep cuts and fills, and the physical properties
of the soil are changed (See Figure 1).
Figure No. 1. Accelerated erosion and excessive
sediment deposition resulting from exposure of soils
to falling and running water. Largo, Md.
-------
The energy responsible for erosion is provided by falling
rain and flowing runoff water. One inch of precipitation
falling on one acre of exposed soil weighs lio tons.
In the lower portion of the Potomac River Rasin, where
the average annual rainfall is about 40 inches, ar>orox-
imately 4,500 tons of rain fall on each acre of land
during the year. This falling rain and flowing runoff
provide the energy required to erode large quantities
of soil from areas under development and transport it
farther downstream. Fortunately, the precipitation in
this area is well distributed through the year (2).
If natural vegetation is left upon land being developed,
the kinetic energy of the falling rain is dissipated.
If it is removed, the bare and disturbed soil receives
the full force of the energy. Raindrops strike the
ground with a velocity of about 19 miles per hour, like
miniature bombs. They knock individual soil particles
loose and compact the exposed soil surface. Runoff in-
creases as the compacted soil becomes less permeable;
and the soil particles loosened by rain drops are carried
down the slopes by overland flow. The impact of rain
falling for a period of from one to four minutes is
known to decrease infiltration to such an extent, even
in sandy soils, that up to 98 percent of the rainfall
runs off (2). Runoff moves as sheet flow or becomes
concentrated in rills and gulleys (figures 2, 3). It
is dynamic in that it has energy to erode and transport
soil particles. If the available energy is greater than
the sediment load being carried, the moving water will
erode to obtain the additional sediment. If the load
is greater, deposition of transported material will occur.
Normally, runoff builds up rapidly to a peak and then
diminishes. Excess quantities of sediment are derived
by erosion principally during higher flows (^igure 4).
During lower flows, as runoff velocities decrease, the
transported materials are deposited to be picked un by
later high flows (Figures 5, 6). In this way, sediments
are carried downstream intermittently from the source
area. A study of sedimentation due to highway con-
struction and land development in the Scotts Run area
of Virginia showed that 99 percent of the sediment dis-
charged occurred during periods of high flow which took
place during only 3 percent of the period of measure-
ment (3) .
-------
Figure No. 2. Rills developed on newly-constructed
highway embankment. Alex City, Alabama.
-------
Figure No. 3. Gulleys developed in ground exposed
to runoff over the winter. Scale shows depth in
feet. Vancouver, Washington.
-------
CO
C9
o
u
20.00
15.00
10.000
5000
19.0
18.5
18.0
C9
<
ca
0600
1200
1800
2400
TIME. IN HOURS
Figure No. 4. Variation in sediment concentration
and stream stage for a typical storm-runoff period;
Scotts Run Basin, Va. (From USGS Water Supply
Paper 1591-E).
-------
, . tu
Figure No. 5. Excessive sediment deposition from
unprotected fill slope during highway construction,
Maryland, US40 and US 29.
-------
f*. *£-
S^Mr^f ' ^
r
-------
EFFECTS OF EXCESSIVE SEDI'IENT LOAHS
Over one billion tons of sediment reach the riven of
our country each year. Approximately 1° percent of this
quantity is contributed by erosion from lands undergoing
highway construction or land development (4). Although
the quantities may be small compared to the total, they
could represent over one-half of the sediment loads carried
by streams draining small v/atersheds under develooment.
Sediment yields in streams flowing from urbanized drain-
age basins vary from approximately 20° to 500 tons per
square mile each year. In contrast, the urbanizing areas
have a yield of from 1,000 to 100,000 tons (5). It is
easy to realize the tremendous quantities of sediments
annually reaching our streams and rivers since an estimated
4,000 acres of land are undergoing development each day for
housing, highway construction, and industrial sites (4).
For very small areas, where construction activities have
altered the soil mantle and vegetative cover, sediment
derived from one acre of land may exceed 20,^00 to 40,000
times that obtained from adjacent farm or undeveloped
woodlands in an equivalent period of time.
Wherever the velocity of streams carrying sediment de-
creases, deposition occurs. The excessive quantities o*
sediment cause costly damage to water areas and to public
and private lands (Figure 7). Obstruction of stream
channels by masses of deposited materials reduces their
hydraulic capacity which, in turn, causes an increase
in flood heights and a consequent increase in damages
(Figure 8). Sediments often fill drain ditches along
roads and railroads, and plug culverts and storm sewers
(Figure 9, 10, 11). Municipal water supnlv reservoirs
lose storage capacity, and the cost of filtering the
muddy water becomes excessive. The added expense of water
purification amounts to millions of dollars each year.
The aesthetic attraction of many lakes and reservoirs
used for swimming, boating, fishing, and other water-
related activities is reduced greatly (Figure 12).
Some published reports indicated that over 600 miles of
streams in the State of Virginia alone have been affected
by excessive quantities of sediment (4). To remove these
deposits and repair damage involved will be costly (Figure
13). Estimates of the cost of engineering, surveying,
reconstruction, and removal of deposited materials reach
approximately $4,000,000.
11
-------
Figure No. 7. Deposition of sediments from erosion
of newly-constructed athletic field farther upslope.
Washington, D. C.
12
-------
Figure No. 8. Sediment-choked stream channel. Ox-
ford, Massachusetts.
13
-------
Figure No. 9. Sediment deposited in energy dis-
sipator due to road construction. Lake Tahoe,
Calif.
14
-------
V;-,,'
Figure No. 10. Sediment from subdivision under
development plugging culvert. Lake Tahoe, Calif.
15
-------
Figure ?Io.
frora soils
11. Erosion ancl deposition of sedinent
exposed to rainfall and runoff. Bov/ie,
1C
-------
l?i
i " *.:
Figure No. 12. Excess deposition of sediments in
lake due to accelerated erosion activity in water-
shed. Lake Barcroft, Va.
17
-------
Figure No. 13. Erosion caused by runoff during
construction of new school. Pontiac, Michigan.
18
-------
The general effect of fine-grained sediments such as
silts and fine sands in an aquatic environment is to
reduce drastically both the kinds of organisms present
and their total number. The sediments alter the exist-
ing environment by screening out sunlight and changing
the heat radiation. As particles settle to the bottom,
they form a blanket which creates an undesirable environ-
ment for organisms which normally occur (Figure 8).
It often smothers developing eggs of fish and also other
organisms. Coarser-grained materials also blanket
bottom areas to suppress bottom life. Where currents
become strong, the abrasive action of these materials
has a severe effect upon the benthos.
Other adverse effects of excessive sediment deposition
on the stream systems or on downstream receiving waters
can result from nutrients or pollutants which may be
adsorbed on fine-grained soil particles (6). Nutrients
such as phosphorus and nitrogen in generous amounts can
cause accelerated eutrophication (enrichment) of waters
with the accompanying increases in algal vascular plant
nuisances, foul odors, and water treatment problems.
Organic matter such as fatty acids, higher-order alcohols,
and products of plant life also may be adsorbed to soil
particles to contribute to displeasing taste and odor
in water supplies.
TEMPORARY EROSION AND SEDIMENT CONTROL MEASURES
Temporary erosion and sediment control measures should
be used to correct detrimental conditions: that develop
during construction operations; that were not predicted
during project design; that are needed temporarily to
control erosion or sediments that become problems during
construction but are not associated with permanent
control (7).
Planning
To be most effective, temporary controls must be initiated
during the design stages of development projects (Figure
14, 15). Special provisions should be made to require
that operation of construction equipment does not create
sedimentation problems. Fording of streams should be
minimized, and if certain crossings are used consistently,
temporary bridges should be required. Tracks of wheeled
vehicles should not be left to initiate erosion activity.
19
-------
Figure No. 14. Erosion prevention and beautification
work being done concurrently with construction.
Tysons Corner Shopping Center, Va.
20
-------
-
Figure ito. 15. Hillside development planned to
reduce danger of erosion or landsliding. Contra
Costa County, Calif.
21
-------
Special efforts must be made to minimize the areal extent
of exposed soils at construction sites and the steepness
and length of cut and fill slopes. Also, some means must
be devised to prevent runoff water from concentrating or
flowing at erosive velocities (Figure 16). Construction
schedules should be programmed to permit installation of
permanent sediment and erosion control structures as
soon as possible, particularly intercept drains, diversion
channels, berms, and other structures used to divert run-
off from areas of erodible soils. Intakes for incom-
pleted permanent drainage structures should be protected
from inflow of sediment-laden waters (Figures 17, 18).
Figure No. 16. Disturbed soils left exposed for
period of 2 years incurred severe erosion with
subsequent deposition of sediments in downstream
areas. Highway construction, McLean, Va.
-------
Gutter
Storm sewer structure
r~W~r*v
Anchor with two stakes
driven into the ground
Figure No. 17- Temporary barrier of hay bales to prevent
sediment-laden water from entering incomplete storm sewer
system. (Revised from Reference No. 11).
23
-------
Plywood top
Building block laid in throat-
web horizontal
Sand & gravel filter
V *£$\
\d$$
x*?i -»»{*<*
jp£f<*.: &:&*%
^.f^vV-.-.q;.;^
^rr?v n-H^a?
' -» .
«
__-
I
«
fr Building block
H Gutter section
j^VfiAtJW??'
e "a. 1C. Sand and gravel filter protecting
intake area of incomplete storm sewer system.
(Revised from Reference No. 11).
-------
The type/ size, extent, and distribution of temporarv
control meausures required at a site will depend princi-
pally upon the distribution and intensity of precipitation;
the credibility of the soils; and the topographic relief,
size, and geometric configuration of the site area. In
the western U. S. where the rainfall is seasonal and
intense, larger and more elaborate control structures mav
be needed than in eastern areas where precipitation is
more evenly distributed throughout the year (Figure 19) .
In Los Angeles, for example, adequate temporary sedinent
and erosion control is required to be provided, and main-
tained in good working order, at construction sites between
November 1 and April 15 of each year (8). Earlier removal
is permitted only upon approval by the County. in eastern
areas, where rainfall is distributed more uniformly
throughout the year, temporary control structures are
less elaborate but must be provided periodically as storms
occur. Seeding and revegetating activities are very use-
ful in the eastern areas; but in the arid west they may
provide fewer protective benefits for soils, particularly
for temporary control.
There probably is little agreement on the meaning of
"adequate" erosion and sedinent control. Temporary
measures used during construction activities do not pre-
vent sedimentation processes from occuring, thev onlv
control them. As the energy responsible for sedi-nent-
ation processes is provided by fallir><7 and flowing water,
it is essential that control measures effectivelv dissipate
this energy. Exposed soils must be protected from the
impact of rainfall. Runoff must be diverted from erodible
areas and its velocity reduced. Sediments being transnorted
by water should be trapped in sediment basins located
in the construction site area.
The following paragraphs provide information on physical
structures and practices which are useful in providing
economical and effective control of erosion and sediment
deposition. Host of these control measures have been
required on various construction projects, or have been
suggested for use, by the various organizations con-
cerned with control.
25
-------
'M'juro 'To. 1?. Large, '/e
in construction site am a
-,ir!i-nn
or
r'-linc 'Jnivorr^ity,
o" Count ^nrr.lneo
r^li^ornia.
-------
Surface Protection of Exposed Soils
Exposed soil surfaces can be protected from the impact
of falling rain and the energy of runoff water by in-
stalling coverings formed from mulch; sheets of plastic;
burlap, or jute netting; temporary growths of fastgrowing
grasses; or sod blankets.
Mulch consists of hay, straw, wood chips, corn stalks,
bark, or any other suitable protective material. It can
be anchored to slopes with liquid asphalt, stakes, covered
with netting, or worked into the soil with various types
of equipment to provide additional slope stability and
to decrease erosion from runoff water (^igure 20, 21,
22). Often sheeps-foot rollers are used to embed mulch
in the soil and to further compact the surface lavers.
Figure No. 20. Hydroseeder applying seed, fertilizer
and raulca on cutslope adjacent to newly-constructed
road. Spalding County, Georgia
27
-------
Figure No. 21. After seeding and fertilizing, the
slope was mulcned and covered with netting. Cereal
Springs, Illinois.
28
-------
:
Figure No. 22. Fiber netting staked to slope to
prevent erosion. Edgewater, Maryland.
-------
Plastic sheeting, covers formed by plastic sprays, or
asphalt linings also are useful in protecting erosion-
susceptible soils. Liquid plastic sprays are in the
developmental stages, particularly in areas o^ seasonal
rainfall. They may be found to be useful in these areas
as seeding can be done during, or prior to, installation
with the finished cover protecting and supporting the
seeds for later germination. In areas of sterile soils
where establishment of vegetation is difficult, plastic
spray covers may be extremely useful to hold seed, fert-
ilizers, and other additives together on the soil.
Seeding of temporary, fast growing grasses often is most
desirable when final grading cannot be done until a later
date (Figure 23).
Figure No. 23. Newly-seeded, fast-growing vegetation
on bank adjacent to industrial park site. Springfield,
Va.
30
-------
Seed beds should be prepared carefully by working fert-
ilizer and required additives into the soil surface.
Cultivation should be along the contours. Seeds tend
to gravitate to lower portions of small rills where
erosion may start. Here they germinate, protect the
soil, and decrease the velocity of runoff water (^igure
24). Sod often is used as a covering in critical areas
susceptible to erosion. It can be anchored to slopes
with stakes where it also acts to reduce the velocity of
runoff, restrict erosion, and trap sediments (figure 25).
Figure Ho. 24. Contrast between vegetated and bare
slope adjacent to newly-constructed highway. North
Carolina
31
-------
Figure Ho. 25. Vegetated and rip-rapped channel,
is staked to anchor it. Bethesda, Maryland.
Sod
-------
Vegetation and mechanical control measures should be used
concurrently. Areas requiring protection involve any
bare erodible soils, but particular emphasis should be
placed upon protecting long, steep slopes and areas
where runoff water can concentrate. All slopes of 2:1
and steeper should be mulched to protect then from pre-
cipitation as soon as they are roughlv graded.
Control of Runoff Water
Control of runoff can be accomplished by the installation
of temporary diversions, benus,slope drains, flow barriers,
or other types of structures which will prevent concentra-
tion of runoff in areas of erodible soils or decrease its
velocity.
Diversion structures consisting of temporary compacted
earth embankment, bales of straw, ditches, and furro\vs
that can quickly be constructed can be used to intercept
runoff before it reaches erodible areas.
They decrease the velocity of the runoff and channel
the water toward erosion-resistant natural or artificial
drainage ways that can carry it out of the construction
site (Figure 25, 26). Generally diversion structures
are constructed across a slope approximately along the
countours. They can be lined with impervious, erosion-
resistant material or, if the gradient if low enough,
unlined. The number of diversions, their spacing, and
extent depends on the area of the site, the volume of
runoff, the erodibility of the soil, density of drainage
channels, the topographic relief, and other factors.
Particularly critical areas for the installation of
diversions is at the crests of cut and fill slopes where
they can prevent runoff from gaining access to the slope.
Berms are broad benches, sloping inward, placed at intervals
along a slope. They decrease the length of the slope and
divert runoff into slope drains where it can be discharged
into nonerodible, or protected areas.
Slope drains often are used to carry water from diversion
structures and the upper part of slopes to topographicallv
(lower areas or into channels where the energy can be
'dissipated. Very portable and lightweight flexible
neoprene tubes are reported to be excellent for temporary
\
\
33
-------
-fc
«*- * - J-, I J
'*&S:
»,:
Figure No. 26. Temporary asphalt-paved apron and
drop chute to prevent erosion. Maryland.
-------
use as they can be installed quickly and by a few men
(Figure 27). Because of their light weight, flaps with
grommets are attached so that the tubes can be anchored
to the slopes with stakes. Being flexible, they can easilv
be curved and fitted with extensions to enable them to
discharge into erosion-resistant areas. The efficacy of
slope drains should not be negated by permitting the
discharge to initiate erosion. In many areas, energy
dissipating structures or sediment traps may be required
to complement the operation of a drain or other structure
(Figure 28, 29).
Trapping of Sediments
Sediments carried by flowing water can be trapned behind
small temporary barriers or in large sediment basins
which decrease the velocity of flow below that necessary
for transportation. Barriers used may be impervious
enough to stop completely the flow of water or may consist
of semi-pervious materials such as sand, gravel, or even
bales of hay (Figures 30, 31, 32). In the latter cases,
the barriers also act as a filter which allows the move-
ment of water but retains most of the sediment load.
The size and cost of structures to trap sediments probably
vary more widely than any others used for sediment pur-
poses. Barriers range from small temporary dikes several
feet in height, constructed of bales of hay or quickly
compacted soils, to large well-designed earth dams
which are engineered to specified requirements. Large
imprevious barriers for sediment basins generally are
constructed with uncontrolled outlet pipes extending
under, or through, them. After the water has deposited
its sediment load in the reservior it can escape through
the riser pipe which extends above the sediment storage
level (Figure 33, 34, 35, 3P). Very large barriers and
sediment basins are used in the west where rainfall is
seasonal and construction is detained for long periods
of time (Figure 19). Semi-pervious barriers may consist
of a dike, formed of bales of hay staked to the ground,
and a low spillway-embankment section of sand and gra-
vel that permits slow movement of water through it
(Figure 31). These types of barriers generally are
small and quickly constructed in areas where rainfall is
uniform and storm periods fairly short.
35
-------
Figure No. 27. Temporary, flexible slope drain. Dis-
charges on gravel energy dissipator to prevent erosion
at discharge end.
Figure No. 20. Diversion channel lined with gravel
to prevent erosion. (From California Division of
Soil Conservation).
-------
Figure No. 29. Gravels placed on banks of diversion
channels to prevent erosion. (From California Div-
ision of Soil Conservation).
Figure No. 30. Temporary semi-pervious barriers.
Straw is placed benind stakes to decrease velocity
of water and trap sediments. Goreville, Illinois.
37
-------
U)
03
Flow
Flow
Top View
Bales of straw staked down
Provide sand and gravel filter outlet
at lower area along with straw bales
Front view
Figure No. 31. Semi-pervious barrier of hay bales with more pervious
embankment of sand and gravel for spillway. (Revised from Reference ?Io,
11).
-------
Figure Mo. 32. Gcni-pervious barrier of
wire fencing. Can he easily adapted for
;nent sediment control. Missouri
brush and
land-develoo-
-------
Figure No. 33. Small sediment basin with outlet pioe
discharging on energy dissipator to prevent erosion at
discharge end. (Revised from Calif. Division of Soil
Conservation).
> ,i,;v^,^-'prF-,'
Figure No. 34. Small sediment basin ready for re-
moval of trapped materials. Note large outlet and
high-water line. Caithersburg, "dryland.
40
-------
Gravel Cone
Collar
Free outlet
Figure No. 35. Large, well-engineered sediment basin dam.
Note outlet pipe with riser, gravel core filter, and seep-
ige-path cut-off collars on outlet. (Revised from Ref. No. 11)
Figure No. 36. Accumulated sediment being removed
from small basin in Maryland.
41
-------
Existing roadway embankments with culverts can be converted
temporarily into sediment traps by the installation
of riser pipes. Alteration of other structures into
temporary control facilities will be limited only bv
the ingenuity of individuals doing the work. This nay
provide additional advantages by decreasing the total
cost of control.
ESTIMATED COST OF
It is extremely difficult to obtain reliable information-
regarding the cost of temporary erosion and se-iment con-
trol used only during construction, or during a temporary
pause in construction. This is due to mar.v factors the
principal one probably being the bookkeeping procedures.
Normally the costs are hidden in unit costs for excav-
ation and compaction, pipe, or other equipment. It is
difficult to define the temporary and the permanent
portion of a facility. ?lany times a temporary control
measure is a permanent one that has been installed earlier
than prior scheduling had called for. In some cases
continuity of grading operations may be interrupter! for
seeding. This creates an additional expense. It is
difficult to determine the portion of this cost that
should be considered due to temporary erosion anri sedi-
ment control. Many large structures such as sediment
basins act as temporary measures during construction
and become permanent recreational features at a later
date to enhance the value of the project (^igure 37).
The proportion of these costs that may be designated
as temporary control also is difficult to cleFine. Con-
trol measures may provide a beneficial effect to the
project in that they prevent erosion and deposition dur-
ing construction which would normally require costly
re-grading or cleaning out of storm sewers, ditches, or
trenches for underground utilities. Climatic conditions
vary drastically in different parts of the country, thus
the type, size, and quantity of control measures required,
and their costs will vary accordingly.
Estimated Cost of Temporary Control
'lost of the estimated costs presented were obtained
during telephone conversations with land develoners,
consulting engineers or geologists involved with dev-
elopment, and State highway departments. ?Jany organiza-
tions were contacted but very few provided data.
42
-------
~. . '"
Figure No. 37. Sediment basin now used as permanent
lake for irrigation purposes. Dulles Airport, Va.
43
-------
Place curb at top of fill
At end of each clay's fill operation, '*?
leave berm at top of slope
Original ground
(scarify before placing fill)
Pegged sod
Sediment trap, or siltation pond
Seed &. Mulch
Figure No. 38. Idealised profile of construction area with many temporary
erosion and sediment control measures installed. (Revised from Ref. No. 11)
-------
The cost for erosion and sediment control on a highway
with an average construction cost of $1,090,000 per mile
was estimated to be between $10,000 and $15,000 per mile.
The cost for control in housing developments was given
as $40 per lot by engineering and geologic consultants
and $100 per lot by developers.
Developers generally felt that costs of temporary control
were excessive even though few actual cost figures were
provided. Most of the engineering and geologic con-
sultants considered that the actural cost of control is
minimal. They felt that the control measures are, in
general, procedures that normally should be done in every
construction project to achieve maximum efficiency.
ADMINISTRATIVE APPROACH
Local governmental agencies constitutionally have the
prime responsibility in planning for the use of private
lands and controlling development within their area of
jurisdiction. Most sedimentation problems, however,
involve entire river systems, or drainage basins, which
may extend across the boundaries of several counties or
states and involve Federal or State-owned lands as well
as private property. As a result, reciprocity between
Federal agencies involved with construction and develop-
ment on Federally-owned lands and the organizations
representing State and local interests is necessary to
obtain effective sedimentation control measures.
Tlany local organizations do not have the trained manpower,
economic capability, or legal authority to undertake
technical studies to determine controls required and
how they should be implemented. Each local governmental
entity has its own particular planning program, zoning
policies, and drainage and flood control facilities.
Erosion control efforts will have a severe effect on
the operations of all organizations involved. To pro-
vide an integrated approach to erosion and sedinent
control, all Federal, State, and local organizations within
a drainage basin must coordinate their control efforts.
A basin-wide task force, which includes representatives
from all concerned organizations within the basin, pro-
bably has the best chance of developing and carrying out
a successful control program. Trained mannower can be
made available by utilizing specific qualified personnel
such as hydrologists, agronomists, engineers, planners,
45
-------
lav/yers/ and managers from the various participating
groups within the task force. By using this reservoir
of technical competence, an effective erosion and sedi-
ment control program can be developed, financed, and
implemented. Development of poor control measures will
lead to improper location of developments, poor construction
practices, and increased runof^; and subsequently to
severe erosion and sediment deposition problems.
The crucial element of a sedimentation control program
is the enforcement of adopted standards. It is not
sufficient for control agencies merely to initiate
ordinances and adopt standards which nal-e temporary
erosion control measures mandatory during highway con-
struction and land development activities. The measures
must be properly carried out and adequately maintained.
Firm, decision-making capability will be a requirement
for the supervisory staff of the control agency. In
addition, an adequate staff for inspection purposes must
be available.
Information available indicates, that in some areas en-
forcement of standards is neglected, often contractors
doing the construction work have been delegated the
responsibility for erosion control by agencies; and the
resident engineers supervising work have no authority
to direct work to be done, even if needed. The general
feeling was indicated in the statement that "you cannot
expect the contractor to assume responsibility when he is
working under directives by the resident engineer."
If this attitude, and similar ones, are prevalent among
administrative agencies, the erosion and sediment control
programs will not succeed. To adequately protect the
quality of the nation's waters from pollution by sediments
derived by erosion in areas undergoing development, it i
-------
REFERENCES
1. National Association of Counties Research Foundation. "Community Action
Guidebook for Soil Erosion and Sediment Control." March, 1970.
2. Interstate Commission On The Potomac River Basin. "Urban Sediment Can
Be Controlled." Proceedings of Winter Meeting. February 17-18, 1966.
3. U.S. Department of The Interior, Geological Survey. "Sediment Movement
1n an Area of Suburban Highway Construction, Scott Run Basin, Fairfax
County, Virginia 1961-64." Water Supply Paper No. 1541-E. 1969.
4. U. S. Department of Housing and Urban Development. "Proceedings of
the National Conference on Sediment Control, Washington, D. C.
September 14-16, 1969." May, 1970.
5. U. S. Department of The Interior, Geological Survey. "Hydrology for
Urban Land Planning - A Guidebook on the Hydrologlc Effects of Urban
Land Use." Circular 554. 1968.
6. Hopkins, G. J. and Popallsky, R. J. "Problems of S1lt 1n Public Water
Supplies" Soil Conservation. Vol. 35, No. 2. September, 1970.
7. U. S. Department of Transportation, Federal Highway Administration.
"Prevention, Control and Abatement of Water Pollution Resulting
from Soil Erosion." Instructional Memorandum 20-3-70. April, 1970.
8. Los Angeles County Engineer copy of "Temporary Erosion Control"
Part of County Building Code (With Exhibits A through G), Draft
of 8/3/71.
SELECTED BIBLIOGRAPHY
1. American Water Resources Association, "Urban Erosion Control"
Reprint of the Proceedings of the Fourth American Water Resources
Conference. 1968.
2. Anderson, C. R. "Erosion Control During Construction Landscape
Aspects." Paper presented at Fiftieth Annual Meeting, Highway
Research Board. January, 1971.
3. Anderson, G. B. "A County in Transition." Soil Conservation
Vol. 36, No. 11. June, 1971.
4. Anderson, P. W. and McCall, J. E. "Urbanizations's Effect on
Sediment Yield 1n New Jersey." Soil and Water Conservation.
Vol. 23, No. 4. July-August, 1968.
5~ Berks County Soil and Water Conservation District. "Handbook for
Erosion and Sediment Control 1n Urbanizing Areas." May, 1970.
6. California Department of Conservation, Division of Soil Conservation
"Problems of the Soil Mantle and Vegetative Cover of the State
of California." January, 1971.
47
-------
7. California Department of Conservation, Division of Soil Conservation
"Sedimentation and Erosion in the Upper Truckee River and Trout
Creek Watershed, Lake Tahoe, California." July, 1969.
8. California Department of Public Works, Division of Highways.
"Temporary Erosion Control" (advanced copy of provisions to be
inserted in Sec. 5 of the Standard Specifications for Federal
aid projects). May 28, 1970.
9. ." "Erosion Control on California State Highways." Sept., 1950.
10. District of Columbia. "Prevention of Generation of Sediment."
Title 8-Health Regulations, Amendment 13. Effective April 11, 1970.
11. Fairfax County, Virginia. "Erosion-Siltation Control Handbook."
Draft of July, 1971.
12. ." "Erosion and Slltation Control Seminar held at George
Mason College, October 3, 1970." Memorandum of October 27, 1970.
13. Grey, H. P. and Ferguson, G. E. "Sediment in Small Reservoirs Due
to Urbanization." A.S.C.E. Proceedings. Journal of the
Hydraulics Division. Vol. 88, No. HY2. March, 1962.
14. Holeman, J. N. and Sauer, Elmer F. "Conservation in a New Town"
Soil Conservation. Vol. 35, No. 2.. September, 1969.
15. Interstate Commission on the Potomac River Basin. "Land Runoff - A
Factor in Potomac Basin Pollution." July, 1967.
16. ." "The Potomac Estuary - A Changing Environment." Proceedings
of 1968 Winter Public Meeting. June, 1968.
17. Kellogg, C. E. and Enderlln, H. C. "What Urban Building Does to Soil
and Water." Soil Conservation. Vol. 35. November, 1969.
18. Maryland National Capital Park and Planning Commission. "Sediment
Control Program for Prince George's County, Maryland." Sept., 1968.
19. Maryland State Roads Commission. "Erosion and Sediment Control Program."
September, 1970.
20.. Maryland State Roads Commission. "Sediment and Erosion Control Measures."
February. 1971.
21. Montogomery County Soil and Water Conservation District. "Erosion and
Sediment Control Handbook." June, 1970.
22. Department of Conservation and Natural Resources, Division of
Water Resources. In Cooperation with U. S. Geological Survey.
"A Reconnaissance of Streamflow and Fluvial Sediment Transport,
Incline Village Area, Lake Tahoe, Nevada." Open-File Progress
Report. 1971.
48
-------
23. North Atlantic Regional Water Resources Study, Coordination Committee,
"North Atlantic Regional Water Resources Study" First Draft.
April, 1969.
24. Placer County, Department of Public Works. "General Specifications,
County of Placer, State of California." January, 1971.
25. Scheldt, M. E. "Environmental Effects of Highways" A.S.C.E. Pro-
ceedlns. Journal of the Sanitary Division. Vol. 93, No. SA5.
26. U. S. Department of Agriculture, Agricultural Research Service
"Proceedings of the Federal Interagency Sedimentation Conference"
USDA Miscellaneous Publication. No. 970. 1963.
27. U. S. Department of Agriculture and U. S. Department of Housing
and Urban Development, "Soil, Water, and Suburbia" A Report of the
Proceedings of the Conference of June 15 and 16, 1967 at Washington,
D. C. 1968.
28. U. S. Department of Agriculture, Soil Conservation Service, "Construc-
tion and Conservation" J. S. 635. December, 1969.
29. ." "Controlling Erosion 1n Construction Sites" Agriculture
Information Bulletlng 347. 1970.
30. ." "Erosion Control for Rural Fringe Land Uses." J. S. 217.
31. ." Northeast Regional Technical Service Center, Upper Darby,
Pennsylvania. "Guidelines for the Control of Erosion and Sediment
1n Urban Areas of the Northeast." 1970.
32. ." "Standards and Specifications for Soil Erosion and Sediment
Control 1n Urbanizing Areas." November, 1969.
33. ." "Model for Developing Soil Erosion and Sediment Control Ordnance
and regulations." Michigan. July 31, 1970.
34. ." "Sediment, Its Filling Harbors, Lakes, and Roadside Ditches"
Agriculture Information Bull. No. 325. December, 1967.
35. ." "Sediment Pollution and Erosion Control Guide for Resource
Conservation." SCS New Jersey Technical Guide. 1970.
-------
36. ." "Soil Conservation at Home" Agriculture Information
Bulletin 244. 1969.
37. ." "Standards and Specifications for Soil Erosion and Sediment
Control 1n Urbanizing Areas." March, 1971.
38. ." Harrlsburg, Pennsylvania, "Surface Water Disposal 1n
Development Area." Information Sheet PA 28, 1970.
39. U. S. Department of the Interior, Federal Water Pollution Control
Administration. "The Practice of Water Pollution Biology."
1969.
40. U. S. Department of the Interior, Federal Water Quality Administration
"Urban Soil Erosion and Sediment Control." Water Pollution Control
Research Series. May, 1970.
41. U. S. Department of the Interior, Geological Survey. "Effect of
Urban Growth on Sediment Discharge, Northwest Branch Anacostla
River Basin, Maryland." From USGS Prof. Paper 450c. 1962.
42. ." "Interim Report on Streamflow and Sediment Discharge 1n the
Colma Creek Basin, Calf1ron1a." Open-File Report. 1969.
43. ." "Urban Sprawl and Flooding 1n Southern California." Circular
No. 601-B. 1970.
44. U. S. Department of Transportation, Federal Highway Administration.
"Prevention, Control, and Abatement of Water Pollution Control by
Federal Activities - Executive Order 11288" Instructional
Memorandum 20-6-67. December, 1967.
45. ." In Cooperation with the U. S. Department of Agriculture,
Soil Conservation Service. "Guidelines for Minimizing Possible
Soil Erosion from Highway Construction." Report to Congress.
July, 1967.
50
------- |