EPA-600/8-76-001-b
ENVIRONMENTAL
.-PROTECTION
AGENCY
EROSION AND SEDIMENT
AUDIOVISUAL TRAINING PROGRAM
WORKBOOK
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JUNE 1976
SOU CONSERVATION SERVICE
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U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
WASHINGTON, D.C. 20460
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EPA-600/8-76-001b
June 1976
EROSION AND SEDIMENT CONTROL
AUDIOVISUAL TRAINING
WORKBOOK
Prepared by
The State of Maryland
Water Resources Administration
and
The U.S. Environmental Protection Agency
Office of Research and Development
Contr ibutory
Department of Transportation
The Federal Highway Administration
Office of Development
and
The U.S. Department of Agriculture
Soil Conservation Service
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DISCLAIMER
Publication of this Workbook does
not signify that the contents
necessarily reflect the views and
policies of the U.S. Environmental
Protection Agency nor the U.S.
Department of Transportation Federal
Highway Administration. Mention of
tradenames or commercial products
does not constitute endorsement nor
recommendation for use.
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CONTENTS
LESSON PAGE
Looseleaf Style
1 Goals, Objectives and Principles of Erosion and
Sediment Control
2 Soils
3 Rainfall-Runoff Relationships
4 Erosion and Sedimentation
5 Plant Materials
6 Control of Runoff During Construction
7 Vegetative Soil Stabilization
8 Stream Erosion Control
9 Temporary Soil Stabilization
10 Control of Sediment Generated on Construction Sites
11 Erosion and Sediment Control Planning
12 Wooded Site Development
13 Foreman-Inspector Responsibilities
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ACKNOWLE DGMENT S
This workbook was prepared under the joint sponsorship of
the Water Resources Administration, State of Maryland and
the U.S. Environmental Protection Agency by Hittman Associ-
ates, Inc.
Publication and distribution is sponsored by the State of
Maryland, the U.S. Environmental Protection Agency, the
U.S. Department of Transportation Federal Highway Admini-
stration and the U.S. Department of Agriculture Soil Conser-
vation Service.
Many participated in the technical guidance and editorial
efforts in preparing this workbook. Messrs. Marshall T.
Augustine, Roger A. Kanerva, Roy E. Benner and Albert E.
Sanderson of the State of Maryland; Messrs. Mark Boyson,
Harold Scholl, and Harold Stephens of the Soil Conservation
Service; Messrs. Daniel O'Connor and Eric Munley of the
Federal Highway Administration; and Messrs. Hugh Masters
and Francis Condon of the U.S. Environmental Protection
Agency deserve special thanks.
The contributions provided to this program by the use of 35
millimeter photographic slides from the U.S. Department of
Agriculture, the Maryland Water Resources Administration,
the Maryland State Roads Commission, the Soil Conservation
Service, the soil and water conservation districts of
Howard, Montgomery, and Prince Georges counties in
Maryland, the Baltimore Public Works Commission, and Rummel,
Klepper, and Kahl, Consulting Engineers in Baltimore are
also acknowledged with sincere appreciation.
Acknowledgment is also given to the perseverance of
Ms. Shirley Simpler of the U.S. Environmental Protection
Agency in preparing tne copy for printing.
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EROSION AND SEDIMENT CONTROL
THE GOAL, OBJECTIVES AND
PRINCIPLES OF
EROSION AND SEDIMENT CONTROL
WORKBOOK
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CONTENT
I. INTRODUCTION
A. Definitions
1. Erosion
2. Sediment
3. Waterway
B. Background
II. THE GOAL OF EROSION AND SEDIMENT CONTROL
A. Achieving effective and reasonable control
B. Caused by man's activities
C. Using the best practical combination of procedures,
practices, and people.
III. THE OBJECTIVES OF EROSION AND SEDIMENT CONTROL
A. Establish and maintain a sediment control program
B. Protect vital land resources from erosion
C. Protect vital water resources and aquatic wildlife
from sediment pollution
D. Provide high quality water for human use
IV. THE PRINCIPLES OF EROSION AND SEDIMENT CONTROL
A. Plan the development to fit the particular topo-
graphy, soils, waterways and natural vegetation
at a site
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B. Expose the smallest practical area of land for
the shortest possible time
C. Apply "soil erosion" control practices as a first
line of defense against on-site damage -
D. Apply "sediment control" practices as a
perimeter to prevent off-site damage
E. Implement a thorough maintenance and follow-up
operation
V REVIEW
A. Definitions
B. Goal
C. Objectives
D. Principles
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I. INTRODUCTION
A. Definitions
1. Erosion - the process by which the land sur-
face is worn away by the action of
wind, water, ice or gravity.
2. Sediment - soils or other surfical materials
transported or deposited by the
action of wind, water, ice or
gravity as a product of erosion.
3. Waterway - any natural or artificial drain-
age way in which waters flow in
a definite direction or course,
either continuously or intermit-
tently, and includes any area
adjacent thereto which is subject
to flooding.
B. Background
The problem of erosion and sediment control
has plagued society and land and water re-
sources since colonial times. Many streams
and rivers were severely damaged by early
agricultural activities.
The early 1930"s saw the start of a nationwide
soil conservation movement which has greatly
1-3
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reduced the agricultural erosion problem.
The application of a typical farm conservation plan
can reduce soil loss from fifteen tons /acre/
year or greater to only five tons/acre/year.
In recent years, however, the problem of ero-
sion and sediment has again been increased.
This time by the trend of greater urbaniza-
tion. IVodern equipment and technology have
been used to create vast networks of high-
ways, sprawling subdivisions, large industrial
parks, and massive shopping centers. In
many cases these activities have resulted in
severe damage to our land and water resources.
It is estimated that from all sources over
four billion tons of sediment pollute the
rivers of this country each year.
In 1972 it cost $2.00 to $3.00 per cubic yard to re-
move sediment from waterways.
In summary, erosion and sediment damages
affect nearly every citizen. Sediment pol-
lution results in:
1. clogged ditches, culverts, and storm
sewers.
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2. Muddied streams, reduced channel
capacities, and increased flood flows.
3. Damaged plant and animal life,
4. Filled-in ponds, lakes, and reservoirs
5. Damaged vital aquatic habitats.
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II. THE GOAL OF EROSION AND SEDIMENT CONTROL
"To achieve effective and reasonable control over
erosion and sediment caused by man's activities
using the best practical combination of procedures,
practices, and people."
A. Achieving effective and reasonable control.
As responsible persons we should try to
achieve the greatest control without putting
unreasonable demands on the other activities
of the construction project.
B. Caused by man's activities.
We are talking about working with people, and
how they affect the quality of their natural
surroundings - land, air, water, and plant
and animal life. Certain of man's activities
must be controlled.
C. Using the best practical combination of proce-
dures, practices, and people.
To control erosion and sediment we need work-
able laws, regulations, and procedures; up-to-
date practices and techniques; and responsible
people working together.
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III. THE OBJECTIVES OF EROSION AND SEDIMENT CONTROL
A. Protect vital land resources from erosion
1. control erosion at its source
2. maximum practical extent - reasonable
control
B. Establish a sediment control program
1. cooperation and involvement
2. prevention
3. flexibility
C. Protect vital water resources and aquatic
wildlife from sediment pollution
1. prevent damage from occuring
2. damaged resources are difficult to restore
D. Provide high quality water for human use
1. vital to man's welfare in the long run
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IV. THE PRINCIPLES OF EROSION AND SEDIMENT CONTROL
A. Plan the development to fit the particular top-
ography, soils, waterways, and natural vegeta-
tion at a site.
1. "Think ahead and don't fight nature"
2. Less problems and damage occur when struc-
tures and grading are designed to fit the
site
3. Careful planning can result in both reduced
damage and savings in project costs
B. Expose the smallest practical area of land for
the shortest possible time.
1. The way in which operations are scheduled
and staged can greatly reduce damage due to
'erosion and sediment
2. Sediment control is another part of the coordin-
ation of a job.
C. Apply "soil erosion" control practices as a
first line of defense against on-site damage.
1. Use practices that control erosion on a
site to prevent excessive sediment from
being produced
2. Examples of erosion control:
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a. special grading methods
b. runoff control structures
c. temporary and permanent vegetation
d. mulches
D. Apply "sediment control" practices as a perimeter
protection to prevent off-site damage.
1. Use practices that control sediment once it
is produced, and prevent it from getting
off-site .
2. Examples of sediment control:
a. sediment traps
b. vegetative filters
c. sediment basins
E. Implement a thorough maintenance and follow-up
operation.
1. A site cannot be effectively controlled with-
out thorough, periodic checks of erosion and
sediment control practices.
2. An example of applying this principle would
be a routine "end-of-day" check to be sure
all control practices are working properly •
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QUESTIONS 1
Fill in the answers
1. is the process by which the
land surface is worn away by the action of wind,
water, ice or gravity.
2. A flowing stream and a storm drain ditch enter-
ing it are two examples of .
3. implication of a typical farm conservation plan can result in
a reduction of soil loss from /tons/acre/
year to only /tons/acre/year.
4. It is estimated that areas undergoing construc-
tion produce as much as times as
much sediment excellent forested areas.
5. The problem of erosion and sediment has been in-
creased recently by .
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QUESTIONS 2
True or False
1. One can expect to achieve 100% control over ero-
sion and sediment all the time.
2. Given experience and a sincere attitude, you can
do an effective and reasonable job of protecting
the land and water resources.
3. Certain of man's activities when carried to ex-
tremes cause severe damage.
4. When we are talking about the job of erosion and
sediment control we are really talking about
controlling nature.
5. "On-the-ground" field personnel are not very im-
portant in erosion and sediment control.
_6. "To achieve effective and reasonable control over
erosion and sediment caused by man's activities
using the best practical combination of procedures,
practices and people" is the goal of erosion and
sediment control.
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QUESTIONS 3
REVIEW QUESTIONS Multiple Choice
(circle the correct answer)
1. To establish a sediment control program we need
a. cooperation and involvement
b. prevention
c. flexibility
d. all the above
2. In order to best protect vital land resources we should
a. stop sediment
b • control erosion
c. prevent construction
3. In our third objective, we want to protect the water by
a. controlling sediment that gets past our first
line of defense
b. preventing erosion
c. fluoridation
4. The human use of water is listed after the protection
of the land and water because
a. land and water are more important
b. land and water are vital to man's welfare in the
long run
c. all of the above
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QUESTIONS 4
Fill in the blanks
1. Less damage and problems occur when structures and
grading are to fit the site.
2. Careful can result in both reduced damage
and savings in project costs.
3. Sediment is another part of coordination
of a job.
4. Special grading methods and runoff control structures
are examples of control.
5. Examples of __ control are sediment traps,
vegetative filters and ..
6. An example of the fifth principle of erosion and sedi-
ment control would be to start a routine "
of " check to be sure all control practices
are working properly.
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POST TEST
1. The process by which the land surface is worn away by
the action of wind, water, ice or gravity is known as:
a. sedimentation
b. pollution
c. weathering
d. erosion
2. A flowing stream and a drainage ditch are examples of
3. A typical farm conservation plan can reduce soil loss
from 15 tons per acre per year to only tons per
acre per year.
4. It is estimated that from all sources, the amount of
sediment that pollutes rivers in this country each
year is:
a. one (1) ton
b. one (1) million tons
c. five (5) billion tons
d- four (4) billion tons
5. The problem of erosion and sediment control has
increased due to:
a. pollution
b. urbanization
c. diversification
d. more leisure time
6. Sediment pollution results in:
a. clogged ditches
b. damaged plant and animal life
c. filled-in ponds, lakes, and reservoirs
d. a and b
e. all of the above.
7. Those people considered very important in any erosion
and sediment control program are:
a. field personel
b. scientists
c. draftsmen
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8. When talking about the job of erosion and sediment
control we are really talking about:
a. controlling wildlife
b. working with people
c. controlling technology
9. The three elements needed to establish a sediment
control program are cooperation and involvement,
prevention and .
10. The best way to protect vital land resources is by
establishing a control program.
11. Careful planning can result in:
a. reduced damage
b. savings
c. a & b
12. An example of erosion control:
a. gravel inlet filter
b. runoff control structure
c. sediment trap
13. A site cannot be effectively controlled without
thorough, periodic checks, of and
control practices.
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EROSION AND SEDIMENT CONTROL
SOILS
WORKBOOK
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CONTENT
I SOIL FORMATION
A. Weathering of Bedrock
1. Physical
2. Chemical
3. Biological
B. Residual and Transported Soils
1. Residual Soil
2. Transported Soil
C. Soil Horizons
II SOIL COMPOSITION
A. Solids and Voids
B. Classification
1. Texture
2. Volume of Soil Constituents
3. Textural Triangle
4. Unified Soil Classification System
and A.A.S.H.T.O.
5. Size Distribution
III IMPORTANCE OF SOIL PROPERTIES IN EROSION CONTROL
A. Size and Weight
B. Soil Structure
C. Cohesion
D. Friction
E. Density
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F. Porosity
G. Permeability
H. Infiltration Rate
I. Water-holding Capacity
J. Chemical Composition
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I SOIL FORMATION
A. The solid rock lying beneath the soil is called
"bedrock." It is made up of a variety of types
of rock, including sandstone, limestone, granite,
shale, marble, schist, and slate. The depth to
the bedrock varies; in some cases it even extends
above the surface, as an outcrop. The composition
of the bedrock is one of the dominant factors which
influence the configuration of the surface
topography. Soil forms as a result of the
disintegration of the bedrock underneath it.
This process of disintegration is called
"weathering."
1. Physical weathering is caused by gravity,
extreme temperature variations, the pressure
of freezing water in cracks and crevices, the
movement of rocks carried by glaciers and
the action of wind and waves.
2. Chemical weathering
a. The principal agent of chemical weathering
is a weak acid which forms when rainwater
combines with carbon dioxide. The acid
that results slowly dissolves soluble
rocks, like limestone.
b. Processes involving oxidation, that is,
processes similar to the rusting of
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iron, are also important types of
chemical weathering.
3. In addition to chemical and physical weather-
ing, biological weathering occurs. Biological
weathering is actually a combination of
chemical and physical weathering, that
results from the activities of plants and
animals.
B. Residual and Transported Soils
1. Soil that forms immediately above the bedrock
from which it is derived is called residual
soil.
2. Transported soil is soil which has been moved
from the area where it originated, by wind,
water, ice, glaciers, or gravity.
C. Soil Horizons
1. The uppermost layer of a soil is the "A"
horizon. It is commonly called "topsoil."
Topsoil is generally high in nutrients and
organic material, and it has a high moisture-
holding capacity.
2. The next lower horizon is the "B" horizon.
a. The "B" horizon contains much less organic
material than topsoil, but it does contain
materials that have been leached out of the
"A" horizon by water percolating downward.
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b. The leached materials that collect in
the "B" horizon often result in the
formation of a "hardpan," that is, a
dense layer that makes it difficult for
water to pass through it.
3. The soil material beneath the "A" horizon is
commonly referred to as "subsoil." When it is
exposed by grading operations it is usually easily
eroded and difficult to stabilize with vegetation.
4. The lowest horizon is the "C" horizon. This
horizon lies just above, and gradually grades
into, bedrock.
II SOIL COMPOSITION
A. Soil is made up of solids and voids. The size,
shape, and arrangement of the soil components will
determine what part of the soil is solids and what
percent is voids.
1.- The solids are the individual soil particles,
together with any organic material that may
be present.
2. The voids are the spaces between the particles.
These voids are filled with air and/or water.
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B. Classification
1. One of the simplest ways of classifying a
soil is by texture. The texture of a soil
is the relative distribution of the various
sizes of particles. Common textural clas-
sifications include gravel, sand, silt, and
clay.
a. Particles from one-quarter inch in
diameter to three inches may be considered
as gravel. Larger pieces are either
cobbles or boulders.
b. Sand ranges in size from about one-
quarter inch down to grains that can
hardly be detected without some mag-
nification.
c. Soil particles smaller than sand are
generally called "fines." These include
both silt and clay sized fractions.
Silt particles are larger than
clay particles.
d. Soils seldom contain pure gravel, sand,
silt, or clay. Instead, a number of
major gradations of sizes are present.
Terms such as "sandy loam," "loamy sand,"
and "silty clay" are often used to des-
cribe mixed soils.
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2. A more descriptive scheme of classification
provides an estimate of the percentage by
volume of each of the soil constituents.
a. In one such scheme, "and" means 35 to
50%; "some" means 20 to 35%; "little,"
10 to 20%; and "trace," less than 10%.
3. Soil scientists use another method of class-
ification, involving the textural triangle.
This triangle is included as the last page of
the workbook.
a. If a given sample of soil contains 30%
clay and 60% silt, to determine the
classification of the sample, you would
read across the 30% line from the left
side of the triangle, which corresponds
to clay, and read down the 60% line from
the right side of the triangle, which
corresponds to silt. Where these two
lines cross, the soil is classified as
silty-clay loam. It would also contain
10% sand, as you can see by finding the
line on the bottom of the triangle,
which corresponds to 10% sand, and read-
ing up to the point where the silt and
clay lines cross.
4. Two other popular classification systems
are the Unified Soil Classification System,
and the A.A.S.H.T.O. Soil Classification
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System, which stands for the American Assoc-
iation of State Highway and Transportation
Officials.
a. Both of these systems of classification
use textural properties of the soil as
well as engineering properties.
b. They are used extensively by engineers
and earth scientists for classifying
soil for construction use.
5. Size distribution means the percentages
by weight, of sand, silt, and clay as well
as larger constituents in the soil.
a. This is accomplished by sieving the
soil, through the use of a number of
sieve or screens of various mesh sizes,
to separate the various sizes of part-
icles in the soil.
b. By dividing the weight of the material
in each sieve by the weight of the
total soil sample, the percent of each
size fraction can be determined. From
the percentages of the various size
fractions, the texture can be determined,
III SOIL CLASSIFICATION IN EROSION CONTROL
A. The size and weight of the particles influence
the susceptibility of a given soil to erosion.
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1. Larger, heavier particles are less likely
to be detached and carried away by splashing
or flowing water than smaller or lighter
particles.
2. When a particle is detached and carried
away by runoff, size, shape, and weight
also determine the distance the particle
is transported.
a. As runoff slows, the larger, heavier
particles are deposited first.
b. Most sand-size sediment particles will
settle out of calm water in a matter of
seconds, but some of the small, light
clay particles will take days, weeks,
or even longer to settle to the bottom.
B. The arrangement of the soil particles, that is,
the soil structure, is also an important factor
in the resistance of a soil to erosion.
1. A soil in which the individual particles do
not stick together is "structureless." Sand
is an example of material devoid of structure.
2. When the particles cling together to form a
larger, distinct unit, the soil has structure,
Different types of structure occur in natural
soil. The type of structure depends on the
way the particles are bound together.
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3. Common types of soil structure include
platey structure, prismatic structure,
blocky structure, and granular structure.
C. The binding force that clay provides in a soil
is called "cohesion."
1. The shape and arrangement of the clay part-
icles, the moisture in the soil, and other
factors, influence the cohesiveness of the
soil.
2. As a general rule, the greater percentage
of fines, the more cohesive a soil will be.
3. The plasticity of a soil tells a great deal
about its cohesiveness. Usually, the more
plastic a soil is, that is, the more it can
be molded, the more cohesive it is. High
plasticity indicates a high clay content.
a. Provided that the clay does not expand
too much when it is moist, a small amount
of it in a granular soil will improve the
resistance of the soil to erosion.
b. If a soil contains clays such as bentonite,
that expand a great deal when they are wet,
the presence of these types of clay in
granular soil may actually decrease the
ability of the soil to resist erosion.
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D. Friction is the resistance created when two
surfaces are rubbed together.
1. Soil particles rubbed together produce
friction.
2. The "shear strength" of a soil is a mea-
surement that combines the frictional re-
sistance between the soil particles and
the cohesion.
a. The measurement of shear strength is
used a great deal by soil and geological
engineers, in designing earthen struc-
tures and foundations, and in predicting
potential landslides and slumps.
1. Slumping or landslides can occur
when excessively steep cut slopes
or filled slopes are constructed,
or when a steep cut slope is under-
cut by moving water. Undercutting
often occurs along waterways and
shorelines.
E. In addition to the shear strength of a soil,
the density of a particular soil has a major
effect on its strength and its erodibility.
1. Density is the measurement of the unit-
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weight of a soil, and it is usually
expressed in pounds per cubic foot.
2. The lower percentage of voids in the soil,
the greater the density of the soil.
3. Compaction not only increases the density
of the soil, by eliminating many of the
voids, it also increases the internal
strength of the soil, thus reducing
erosion.
F. The porosity of a soil is the percentage of the
soil occupied by voids, that is, space filled
with air or water.
1. You need a certain amount of soil moisture
in order to achieve a high degree of soil
compaction.
2. The amount of water filling the voids in
soil is expressed as the "degree of
saturation." This effects the resistance
of the soil to erosion.
a. At 100% saturation, all of the void
space is filled with water. The soil
is then said to be "saturated."
G. Another important factor in the ability of the
soil to resist erosion is the permeability of the
soil. Permeability is a measurement of how fast
water flows through a soil.
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1. It is usually expressed as the number of
inches of water passing through the soil in
an hour.
2. Permeability is an important property of a
soil, because it has a major influence on
how much rainfall moves into the
soil, and how much remains on the surface,
becoming runoff.
3. The greater the runoff, the greater the
possibility of erosion.
4. Permeability is not always related to
porosity. In fine-textured soils such as
clay, the permeability may be very low, even
though the porosity is high.
a. This difference between the permeability
and the porosity occurs partly because
of the small size of the pores between
the individual particles. The small
pore spaces make it difficult for water
to pass from one pore to another.
b. Also, there are few connections between
pores, thus making it difficult for
water to penetrate.
5. On the other hand, in coarse, granular soils,
the voids are relatively large, and connected
with each other; thus the permeability is high.
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H. Another factor effecting the erodibility of
a soil is the infiltration rate.
1. The infiltration rate is the rate at which
water enters the soil. It differs from
permeability in that permeability is the
measure of the rate at which water moves
through the soil.
2. Infiltration rate is expressed as inches
of water entering the soil per hour.
3. The infiltration rate is affected by the
permeability of the soil and the condition
of the soil surface as well as the
permeability of the various soil layers
beneath the surface layer. The permeability
of a soil can only be as great as the
permeability of its least permeable layer.
You should never guess the infiltration
rate of a soil from surface observations
or shallow test cores.
4. Soils that remain saturated for long periods
of time because there is a layer of low
permeability in the profile, or because of
a high level of ground water, are called
"poorly drained" soils.
a. This type of soil is difficult to manage
and presents drainage problems when
buildings are placed on it.
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I. The ability of a topsoil to retain water is
known as its "water-holding capacity." The
water-holding capacity of a soil affects the
ability of the soil to support vegetation, and
therefore affects is erodibility.
1. The texture of the soils and the presence
of organic material are the primary factors
in determining the water-holding capacity.
a. Soils containing over 25 to 30% silt
and clay-size particles are usually
able to hold enough water within the
voids of the soil to sustain a vigorous
vegetative cover.
b. Soils that contain less than 30% fines
are "droughty" soils, and usually require
more management to attain a healthy stand
of vegetation.
c. Other factors, such as the location of the
groundwater table, the temperature, the
precipitation, and the ground slope also
effect the availability of moisture and
the ability of the soil to support vege-
tation.
2. When soils are saturated with moisture, frost
heaving sometimes occurs, during periods of
freezing weather. The moisture in the soil
freezes. Ice crystals expand and lift up a
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layer of soil. Under extreme conditions,
well-rooted vegetation may be uprooted and
large chunks of material may tumble downhill.
a. It is almost impossible to prevent erosion
in these areas until the problem of water
saturation is solved. This problem may
be solved by installing tile under the
ground to drain the soil.
J. Another important characteristic of the soil that
affects the growth of vegetation, and hence, the
ability of the surface to resist erosion, is the
chemical composition of the soil. Surface drainage
may also be needed.
1. The materials most important to the growth
of plants are often those which are relatively
scarce in soils. In some cases they are absent
altogether.
2. The three major nutrients required by plants
are nitrogen, phosphorus, and potassium.
a. Very little nitrogen is present in sub-
soils. The main source of the nitrogen
used by plants are the decayed plant and
animal remains present in the topsoil,
and the nitrogen which has been removed
from the air and converted into usable
forms by certain bacteria in conjunction
with plants known as legumes.
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b. Phosphorus and potassium are present in
bedrock minerals, and become part of the
soil as the bedrock weathers.
3. The presence of these materials can be determined
by testing. Your local agricultural agent can
either do the testing or tell you where it can
be done.
4. If a soil is deficient in any of these
materials, you should add the proper type
of fertilizer before planting. Most soils,
topsoil included, will require the addition
of fertilizers.
5. Plants need many other nutrients in very small
amounts. These nutrients are often called
"trace elements." Examples include iron,
sulfur, magnesium, zinc, and copper.
Ordinarily these chemicals are present in
great enough quantities that you do not
have to add them before planting.
6. Another very important factor that effects
plant growth is pH. This term describes how
acidic or alkaline a soil is.
a. A pH of 7 is neutral. A pH between 7
and 14 is alkaline, or basic. A pH
below 7 is acidic.
2-17
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b. If the pH is lower than 4, most
plants can not survive. When the
pH ranges from 4 to 5, many ever-
greens , some legumes, and a few
other plants will survive.
c. As the pH increases above 5, many
more species will flourish. Soil
pH above 8.5 is too alkaline for
most plants.
d. You can handle the problem of acid
soil by selecting plant materials
that are compatible with the acidity,
by raising the pH by adding lime or
by covering the acid soil with soil
that is not too acid. Very alkaline
soils can be treated with sulfur,
sulfuric acid or gypsum depending
upon the soil chemistry.
e. As with the minerals, you must
perform certain tests to determine
tne pH. Your local agricultural
agent should be able to provide
help in getting a soil tested.
2-18
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Questions 1
Fill in the blanks.
1. The massive area of rock lying below soil is
called .
2. Soil is formed by the process of rock disintegration
called .
3. and are causes of
physical weathering.
4. Oxidation is an important type of
weathering.
5. Biological weathering is a combination of chemical and
physical weathering resulting from the activities of
s_ and s.
6. Tree roots growing in the crack in a rock, not only
exert a pressure that forces the rock apart, they also
produce which slowly
the rock.
2-19
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Questions 2
Circle the correct answer or answers.
1. Soil that forms immediately above the bedrock from
which it is derived is called
a. topsoil
b. residual soil
c. "D" horizon
d. sandstone
2. When quartz or other materials resistant to weathering
occur within the bedrock,
a. the resulting soil is fairly uniform in appearance.
b. an acid formed by rainwater and carbon dioxide
slowly dissolves the rock
c. the soil is transported from the area by water,
wind, ice, or gravity.
d. boulders and outcrops result in the soil
3. Transported soil (by water)
a. particles often have rounded edges
b. is fairly uniform in appearance
c. usually continues much the same all the way down
to the bedrock
d. should be stockpiled during construction activities
for later use as topdressing
2-20
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4. Good examples of transported soils include
a. gravel and slate
b. marble and granite
c. clay and silt
d. sand and gravel
5. The "A" horizon of a soil is
a. usually called "subsoil"
b. rich in organic material
c. able to support a vigorous vegetative cover
d. difficult to stabilize with vegetation
6. Topsoil
a. often has a high moisture-holding capacity
b. contains little organic material
c. is another name for the "C" horizon
d. gradually grades into bedrock
7. Leached materials in the "B" horizon
a. are rich in nutrients and organic matter
b. have a doughy or plastic consistancy
c. expand many times their original volume during
heavy rainfall
d. may result in the formation of a "hardpan"
2-21
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Questions 3
True or False
1. Soil is made up of solids and voids.
2. The texture of a soil is determined from the
size of the individual soil particles, together
with any organic material that may be present.
3. Soil particles from one-quarter inch in dia-
meter to three inches can be considered as
cobbles or boulders.
4. Soil particles smaller than sand are generally
called "fines."
5. Clay particles are generally coarser than
silt particles.
6. Silt has some plasticity, but not as much as
clay.
7. Soils seldom contain pure gravel, sand, silt,
or clay; instead, a number of major gradations
of sizes are present.
2-22
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Questions 4
Fill in the blanks.
1. When soil particles cling together to form a larger,
distinct unit, the soil has .
2. G structure is easily eroded.
3. The binding force of clay in soil is called
4. The greater the percentage of f , the more
cohesive the soil will be.
5. is more cohesive than silt or sand.
6. The of a soil is a measurement that
combines the frictional resistance between the soil
particles and the cohesion.
7. The measurement of shear strength is used by soil and
geological engineers in predicting potential 1 s_
and s s.
2-23
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Questions 5
Each of the following sentences contains one error. Write
the letter that corresponds to the incorrect word or phrase
in the blank provided.
Density is the measurement of the unit-weight of
A
a soil, and it is usually expressed in pounds per
A B
cubic foot. The higher the percentage of voids
B
in the soil, the greater the density.
C
Compaction not only increases the density of the
A
soil, by increasing many of the voids, it also
_ _
increases the internal strength of the soil.
C
The porosity of a soil is the percentage of the
A
soil occupied by voids, that is, spaces filled
A B
with air or water, which is important in order
B C
to determine its texture.
2-24
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_Soils become more resistant to erosion when
A
the soil is saturated, because the particles
B C
are partially supported by the water and be-
C
cause the bonding strength between the particles
D
is less when the particles are completely sur-
D E
rounded by_wa. ter.
E
A soil that is rapidly permeable has many connected
A
void spaces; most clay soils are quite permeable.
B
2-25
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Questions 6
Circle the correct answer or answers.
1. The amount of water present in a soil is known
as the
a. moisture content
b. water-holding capacity
c. rate of infiltration
d. porosity
2. The primary factors in determining the water-holding
capacity are the
a. percentage of fines
b. presence of organic materials
c. shear strength
d. chemical composition
3. The materials most important to the growth of plants
are
a. water
b. plant foods
c. oxygen
d. C02
4. The main scources of nitrogen used by plants are
a. legumes
2-26
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b. lime
c. decayed plant and animal remains
d. zinc and copper
5. Trace elements include
a. phosphorous and potassium
b. copper
c. sericea lespedeza
(j. silicon
6. The pH of a soil describes
a. The required fertilization
b. the presence of trace elements
c. how acidic or alkaline a soil is
d. the conversion of nitrogen into forms which plants
can use
7. A pH of 7 is
a. alkaline
b. acidic
c. basic
d. neutral
8. Most soils are
a. slightly acidic
b. slightly alkaline
c. unable to support most plant species
d. able to support only evergreens and legumes
2-27
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Questions 7
True or false
1. One way a soil forms is from the breakdown of
bedrock, a process called weathering.
2. Residual soils form some distance away from
the area where their parent materials first
originated.
3. Transported soils usually show layering.
4. The relative distribution of the various soil
particles is known as layering.
5. Soil textures range from gravel, which is the
largest, down to sand, which is the finest.
6. Soils are usually made up of various mixtures
of sizes.
7. Eroded particles of medium sand quickly settle
back to the bottom of a stream or pond.
8. Cohesion is the binding force in a clay
soil.
9. A soil containing large amounts of fine
sand is highly resistant to erosion.
2-28
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10. The measurement of how fast water can flow
through the soil is called the "rate of
saturation."
11. Sandy soils are more permeable than those
containing large amounts of clay.
12. The rate of infiltration is the rate at
which surface water enters the soil.
13, Soils which contain less than 25 to 30%
silt and clay, or "fines," usually cannot
hold enough water to support a good growth
of vegetation.
14. Most subsoils generally contain sufficient
nutrients and do not require the addition
of fertilizers.
2-29
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Textural Triangle U.S.D.A,
100% clay
10
100% sand
90 80 70 60 50
40 30
Percent sand
20 10
100% silt
2-30
-------
EROSION AND SEDIMENT CONTROL
RAINFALL - RUNOFF
RELATIONSHIPS
r
r
c
c
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WORKBOOK
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CONTENT
I. BASICS OF PRECIPITATION
A. Rain, Snow, Sleet, and Hail
B. Climatology, Hydrology, and Hydraulics
II. THE HYDROLOGIC CYCLE
A. Definition
B. Precipitation
C. Infiltration
D. Runoff
E. Surface Water
F. Groundwater
G. Evaporation
III. PRECIPITATION
A. Four Basic Forms of Precipitation
B. Orographic
C. Frontal
D. Convective
E. Cyclonic
F. Local Factors
G. Average Yearly Hydrologic Cycle for the United States
H. Precipitation and Runoff
IV. FLOODS, FLOODPLAINS, AND WATERSHEDS
A. Floods and Floodplains
B. Watersheds
3-1
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V. RUNNING WATER AS AN AGENT OF EROSION
A. Factors Effecting Velocity of Running Water and
Resultant Erosive Force
VI. FACTORS EFFECTING AMOUNT OF SURFACE RUNOFF
A. Need to Understand How Factors Work
B. Precipitation
C. Soil Type
D. Topographic Factors
E. Vegetative Factors
VII. MAN'S ACTIVITIES WHICH EFFECT AMOUNT OF SURFACE RUNOFF
A. Removal of Vegetation
B. Creation of Impervious Areas
C. Excessive Runoff can be Prevented
3-2
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I. BASICS OF PRECIPITATION
A. Precipitation includes rain, snow, sleet, and hail.
1. Rain falling, accumulating, and flowing over
poorly protected soil, causes the majority of
soil erosion and sediment pollution.
B. Climatology, Hydrology, and Hydraulics
1. Climatology is the science that deals with
climates, their phenomena, and the causes
involved.
a. It includes the study of temperature,
wind velocity and direction, and
precipitation.
2. Hydrology is the science that deals with the
waters of the earth.
a. It is the study of the occurence of the
earth's waters, their circulation, and
their distribution.
b. Hydrology is the study of the reactions
of the earth's waters with their environ-
ment, and the relations between these
waters and living things.
c. It also deals with the full life history
of water on the earth and includes rainfall
amounts and intensities.
3-3
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3. Hydraulics is the field that deals with
practical applications of water, as well
as other liquids, in motion. As erosion
and sediment control specialists, we are
concerned with the practical applications
of water in motion, our main concern is the
energy of water moving over bare soil.
4. These three fields are closely related
and embrace a number of sciences and
engineering disciplines.
II. THE HYDROLOGIC CYCLE
A. Rainfall is part of a cycle, the "hydrologic cycle."
This cycle is the continuous circulation of water,
from the earth to the atmosphere, and back again.
B. Masses of air carry clouds through the atmosphere.
These clouds are actually composed of billions
of small droplets of water.
C. Eventually, when the conditions are right, the
water vapor condenses enough, so that precipitation
forms.
D. The precipitation falls.
3-4
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E. Most of the precipitation reaches the surface
of the earth. Here, much of it soaks into the
soil. This process is called "infiltration."
F. The part of the precipitation which does not
soak into the soil eventually runs into the
ocean by way of streams and rivers. It is
called runoff.
G. These rivers and streams, along with the lakes,
ponds, and oceans, belong to the surface water
portion of the hydrologic cycle. Any water on
the surface of the ground is surface water.
1. We are most interested in surface waters,
because flowing surface water acts as the
crimary agent of erosion, in most areas of
country, and it transports sediment to its
point of deposition.
H. Another major part of the hydrologic cycle is
the groundwater portion. This includes all
water below the surface of the ground.
1. Some of the water that soaks into the soil
is used by plants. These plants, in turn,
give off water vapor, through leaves, back
into the atomsphere. This process is known
as "transpiration."
2. Part of the water that soaks into the
ground percolates beyond the reach of
the plant roots. This water then joins
3-5
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the vast amount of water which is stored
underground.
3. A portion of this underground water
reappears as surface water, in the form
of seeps or springs.
4. Eventually, part of the groundwater returns
to the ocean.
I. The water in the ocean evaporates at roughly
the same rate as the rate at which water flows
into the ocean.
J. It is from this evaporation, as well as the water
transpired by plants and the water evaporated from
plants and the surface of the land, that clouds
form. This completes the hydrologic cycle.
III. PRECIPITATION
A. There are four basic processes by which moist air
releases rainfall and other forms of precipitation:
orographic, frontal, convective, and cyclonic.
Some of these processes are more active than
others, depending upon the part of the country.
B. Orographic precipitation is caused by the inter-
action of moist air with mountains. It occurs
when the prevailing winds carry moist air,
usually from an ocean, over a mountain range.
3-6
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1. As warm air rises, it becomes cooler, and
as cold air falls, it becomes warmer.
2. The cooling of moisture-laden air may
cause it to drop its water on the side
of the mountains toward which the wind
is blowing. This side is called the
"windward" side. The air is now colder
and dryer.
3. As the air that is now colder and dryer
crosses the mountains, it begins to fall
on the sheltered side of the range. This
is the "lee" side.
4. As these air masses fall, they become
warmer.
5. Because of the dryness and the warmth,
little precipitation occurs on the lee
side of the range. These conditions can
create a desert. This type of desert
is called a topographic desert, because
it is the topography which is responsible
for its formation.
C. Frontal precipitation is that which occurs when a
warm air mass and a cold air mass collide. The warm
air mass is otten referred to as a "warm front,"
and the cold air mass as a "cold front." As
the warm air mixes with the cold air, it is
3-7
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cooled and the moisture condenses to form
rain or other forms of precipitation.
D. Convective precipitation is caused by the
upward flow of warm air into the cooler air
above. As the warm air rises, it "piles up"
the water vapor into gigantic clouds, commonly
called thunderheads, which produce thunder-
storms.
E. Cyclonic storms include hurricanes and
typhoons. These storms are characterized
by winds which rotate about a center of
low atmospheric pressure. Very heavy
rains usually accompany these storms.
F. Local factors have an enormous effect on
the amount of rainfall or other forms of
precipitation which fall on the area.
1. As with anything in nature, the amount
of rain that reaches the earth varies
widely from place to place.
2. The average rainfall for Maryland is
about 40 inches per year.
3. Other factors, besides mountains, which
affect the chance of precipitation include
winds, temperatures, and the location of
the area relative to bodies of water,
3-8
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such as oceans and large lakes. Large
bodies of water may provide additional
moisture for precipitation in downwind
areas. They may also cool air masses
sufficiently so that they drop their
precipitation over the water rather than
on the surrounding land.
4. By "intensity of rainfall" we mean
how hard it rains. The intensity of
rainfall is usually measured in inches
of water falling in an hour of time.
A rain which produces two inches in
a one-hour period is a much "harder"
rain that one which measures only
one-half inch in the same one-hour
period.
G. Average Yearly Hydrologic Cycle
1. In a normal year enough precipitation
falls to cover the United States with
30 inches of water.
2. Of the water that falls, two-thirds,
or 21 inches, return to the atmosphere
by evaporation and transpiration, 30
percent, or 8.9 inches, returns to
the ocean through surface runoff,
3-9
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and the remaining one-tenth of an inch
infiltrates and becomes groundwater,
which ultimately returns to the ocean.
H. Precipitation and Runoff
1. The primary aspects of the hydrologic
cycle that erosion and sediment control
specialists deal with are precipitation
and runoff.
a. Precipitation falling as rain
exerts tremendous amounts of energy on
exposed soil. The impact of
the raindrops dislodge and
displace soil particles.
Ensuing runoff displaces
and carries away additional
soil particles.
b. Runoff begins as overland or
sheet flow. This is the
relatively thin layer of
water which begins flowing
over the surface of the
ground when all of the
rain that reaches the sur-
face of the ground does not
infiltrate into the soil.
3-10
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c. When sheet flow begins to
concentrate in small channels, these
are called rills. These rills join
other surface runoff and the
water concentrates in contin-
uously larger channels. All too
often, these channels turn into
large, destructive gullies. Our streams
were formed through this process.
IV. FLOODING AND WATERSHEDS
A. For adequate erosion control and stormwater manage-
ment planning, we need to know how much of the
total precipitation will become surface runoff,
and the rate and speed this water will flow off
the land surface. These factors affect the
frequency and severity of flooding.
B. Floods and Floodplains
1. Flooding occurs when flow is greater than
the capacity of the channel.
2. The flat area on one or both sides of the
channel where the water flows and spreads
out is known as a "floodplain." (Soils in a
floodplain are alluvial soils.)
3-11
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3. Floods are more frequent in some parts
of the country than in others.
a. We can estimate the average frequency and
severity of flooding by observing the flows
in a waterway over a period of many years.
b. The normal amount of water in a channel
is known as "base flow."
c. When a stream receives a large amount of
water from the surrounding area, the water
may overflow the channel banks and begin
to cover the floodplain. The extent of
flooding is described by the frequency
with which a particular water level is
reached.
d. A "two year flood" occurs, on the average,
once every two years. Such a flood has
a fifty percent chance of occurring in any
year.
e. Heavier floods may occur, on the average,
once every 10 years. A flood of this size
would have a ten percent chance of being
equaled or exceeded in any year and
would be known as a "ten year flood."
This does not mean that if one flood of
this size has occurred, the next one will
not come for another 10 years. Such floods
can come at any time - whenever there is
3-12
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a rainfall or melting snow event great
enough to cause a 10 year flood. But
on the average, they occur once in 10
years, twice in twenty years, and so
forth.
4. To allow unrestricted flow of floodwater,
and to prevent damage to life and property,
all restrictive structural and inhabited develop-
ment should be kept out of the 100 year floodplain,
5. If extensive areas in a given watershed have
been made impermeable through construction
activities or other measures, and steps are
not taken to detain runoff, the frequency
and severity of flooding downstream may be
greatly increased.
C. To evaluate the liklihood of floods, we have to
examine the whole watershed. A watershed, or
"drainage basin," is the total ground area which
contributes surface water runoff to a given point.
1. A given watershed is separated from all
adjacent watersheds by a ridge, or "divide."
2. In a given watershed, all the surface
runoff will eventually run to the
lowest point through which the main
stream passes.
3-13
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3. The shape and area of any watershed will depend
upon what point you are interested in. As a
result,, any large watershed can be broken down
into a number of smaller watersheds. These
smaller watersheds are often called "subwatersheds."
a. Whether you choose, to consider a major
watershed, or a subwatershed, depends on the
purpose of your investigation.
V. RUNNING WATER AS AN AGENT OF EROSION
A. There are a number of factors which increase the
speed of water and therefore its erosive force.
1. One factor which increases the rate of flow
is the slope. The steeper the slope, the
faster the water will flow.
a. One way to measure slope is by finding
the ratio of the horizontal distance
to the vertical distance.
b. It is customary to reduce the numbers
to the lowest possible ratio, such as
1 to 1, 2 to 1, 3 to 1, and so on.
Therefore, if a slope goes for 100 feet
horizontally, with a 50 foot change
in vertical distance, it would have a
slope of 2 to 1.
c. Slope can also be expressed as a per-
centage. The percentage represents
the amount of vertical distance that
3-14
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would be covered, if the slope
continued for a horizontal distance
of 100 feet. For a 50 foot rise,
over 100 feet of horizontal distance,
the slope is 50 percent.
2. Another factor that affects the speed of
running water is the roughness or smoothness
of the surface over which the water flows.
a. Water flows faster over a smooth
surface, than over a rough one.
b. This principle is very useful for con-
trolling erosion. For example, if a
slope has been properly "tracked"
with a dozer, the horizontal grooves
will slow the flow of water down the
slope. More of the water will tend to soak
into the soil.
3. The total length of the slope also affects
the speed of water flowing over it.
a. This is primarily because the longer
the slope, the greater the total volume
of precipitation falling on the slope.
b. The increased volume causes an increased
depth of flow and an increased depth of
flow and an increased velocity.
c. We can shorten the effective length of
3-15
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the slope, by using diversion
structures.
VI. FACTORS AFFECTING AMOUNTS OF SURFACE RUNOFF
A. In any given watershed, the amount of surface
runoff depends on a number of factors.
We need to understand these factors,
because in many cases we can reduce
the amount of surface runoff, and
hence, erosion, if we understand how
these factors work.
B. One factor influencing the amount of
runoff is precipitation, especially rainfall.
1. We can make measurements and predict, with
some accuracy, the amount of runoff we can
expect during any given rainfall.
2. We can also predict the amount of rainfall in
a particular place and season, with respect to
the frequency of a runoff event.
a. Rainfall is measured in inches. If
the rain that falls at a certain point
is collected in a container with a
flat bottom and vertical sides, the
total depth of the water in the con-
tainer is equal to the amount of rainfall.
3-16
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b. All rain gauges work on this principle.
More sophisticated raingauges include
mechanisms for automatically recording
the rain with respect to the time it falls.
4. Using these more sophisticated devices, you
can measure the intensity of the rainfall,
as well as the total amount. The intensity
is particularly important, because a rain-
storm with a heavy intensity will generally produce
more runoff than one with low intensity.
a. The reason for this is that the amount
of water the soil can take in is
relatively constant, after an initial
rainfall period that soaks the soil surface.
b. During low intensity rainfalls, most
of the water may soak in, or "infil-
trate." But during high intensity rain-
falls, if the infiltration rate remains
the same, a greater portion of the rainfall
runs off.
5. The soil can only allow a certain amount of
water to infiltrate, at a fixed rate, because
it is composed of a large number of soil
aggregates, with open spaces, or "pores,"
within and between the aggregates.
3-17
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a. Water, pulled by the force of gravity
and by other forces, can infiltrate and
seep downward not exceeding some maximum rate,
This rate depends on the permeability
of the soil.
b. If the rain falls faster than the water
can seep downward through the soil, the
water begins to accumulate on the surface
of the ground and eventually begins to
flow over the ground as surface runoff.
c. At the beginning of a low-intensity
rainfall, the water has plenty of time
to infiltrate. If the rain is light
enough, no overland flow will occur,
until all the pores in the soil are
filled with water, that is, until the
soil is "saturated." When the soil is
saturated, the infiltration rate is con-
trolled by the soil permeability. It then
accumulates, becoming surface runoff.
6. The total quantity of rain which falls is one
of the factors that determine the amount of
runoff. Even a light rainstorm may produce
a large amount of runoff if it rains for a
long period of time.
a. The duration of the rainfall, as well as
the intensity, has an effect on the
amount of surface runoff.
3-18
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C. The type of soil present is another factor
influencing the amount of surface runoff.
1. The permeability of the soil limits the
rate at which water can infiltrate; beyond
this rate, rainfall becomes runoff.
Different soils have different permeabilities.
a. Increased soil permeability decreases
surface runoff. A highly permeable
soil(sands) permit water to seep downward
at a rapid rate. This rapid seepage
prevents water from accumulating on
the ground surface as runoff.
2. During construction activity, much of the
soil is altered from its natural state.
Construction traffic constantly moving over
the surface of the ground compacts the soil,
thus making it less permeable.
a. Increased compaction causes more of the
rain to become runoff.
3. The texture of the soil also effects the
amount of runoff generated by rainstorm.
a. Clay soils are usually much less permeable
than sandy soils. This is because the
structure and arrangement of the clay
particles do not allow water to pass
through as rapidly as it can through
the more permeable sandy materials.
3-19
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D. Another factor that influences the amount of
surface runoff is the topography.
1. The steepness of the slope and the total
length of the slope influence the amount
of surface runoff.
2. More surface runoff occurs on steep
slopes than on more gentle ones.
3. The roughness of the surface also effects
the amount of runoff, by effecting the
speed at which the water flows down the
slope. A roughened slope will slow the
flow of water, allowing more time for
it to soak into the ground. The opposite
is true for a smooth slope.
*
4. Another topographic factor which effects
the amount of runoff within a watershed,
is the total distance over which the water
flows.
a. The more direct the route overland
runoff takes, as it flows to the
major drainage channel, the less
time the water has to infiltrate
into the ground.
b. If the overland flow takes more
circuitous routes to the major
drainage channel, the overall
3-20
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E. In addition to topographic factors, vegetative
factors have an enormous influence over the amount
and speed of surface runoff.
1. Vegetation acts as a natural buffer, that
slows the flow of runoff and increases the
infiltration.
2. Vegetation improves the ability of the soil
to absorb water by providing organic matter
on the surface and in the soil.
3. Vegetation also improves the ability of the
soil to absorb water, by loosening the soil,
and thus increasing infiltration.
4. Plants also remove water from the soil, thus
enabling the soil to accommodate more in-
filtrating surface water.
5. Furthermore, vegetation shields the surface
of the soil from the direct impact of falling
rain, thus preventing compaction detachment and
sealing of the soil surface.
3-21
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VII. FACTORS RESULTING FROM MAN'S ACTIVITIES
A. With modern technology, we can remove the
vegetation from vast areas. But by so doing,
we may greatly increase the amount of runoff
and the resultant erosion.
B. Making areas of the soil impervious to water
by constructing pavements, buildings, and
storm drainage systems also increases the
amount of runoff.
1. Instead of a major portion of stormwater
infiltrating into the soil, most of it
becomes runoff.
a. The massive inflow that results in
the natural waterways, causes
erosion and flooding.
b. The result is'sediment pollution,
aesthetic damage, and danger to
property and lives.
C. This damage is avoidable. Man can control it
without banning all development.
1. Through far-sighted planning, and use
of proper designs and construction practices,
we can develop an area and, at the same time,
manage it in a way that will protect the
environment.
2. Stormwater management is one very important
3-22
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means of controlling the amount and speed
of runoff.
a. Stormwater management is a program
designed to slow the runoff, and,
in some cases, actually decrease
the amount.
b. A number of structures are useful
for managing stormwaters. These
include gravel filled infiltration
structures, retention basins, and
man-made ponds.
3-23
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Questions 1
Fill in the blanks.
1. Rain, falling, accumulating, and flowing over poorly
protected soil, causes the majority of '
and .
2. __^ is the science that deals with
climates, their phenomena, and the causes involved.
3. is the science that deals with the
waters of the earth.
4. is the field that deals with practical
applications of water in motion.
5. It is surface waters which we are interested in, because
flowing surface waters act as the primary agents of
and still surface waters are the
most subject to .
6. The four basic processes of precipitation are
, , and
J-24
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Questions 2
True or false.
Local factors such as mountains effect the amount
and intensity of rainfall in a given area.
In a normal year, enough precipitation falls to
cover the United States with approximately 40 inches of
water.
The energy exerted by raindrops striking exposed
soil surfaces is relatively insignificant as an erosive
factor.
Runoff over bare soil detaches and carries away
soil particles.
5. To allow an unrestricted flow of floodwater, and
to prevent damage to life and property, all development
should be kept out of the 100 year floodplain.
6. Watersheds are separated by a ridge or "divide."
3-25
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Questions 3
Circle the correct answer or answers.
1. If a slope has a horizontal distance of 100 feet and a 50
foot change in vertical height, the slope would be a:
a. 2 to 1 slope
b. 1 to 2 slope
c. 50% slope
d. 200% slope
2. While in motion, water carries soil particles, but as water
loses its motion,
a. it is more likely to cause serious erosion
b. it tends to deposit these transported materials
c. neither of the above
3. Factors affecting the speed of flowing water include
a. the slope
b. the type of diversion structures present
c. the roughness or smoothness of the surface which the
water flows over
d. the total length of the slope
3-26
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Questions 4
True or false.
1. We have little control over the amount of rainfall,
its frequency, or its intensity.
2. We cannot predict with any accuracy, the amount
of runoff we can expect during a rainfall of a particular
frequency.
3. We can predict, with some accuracy, the amount of
rainfall in a particular place for a particular frequency.
4. The rate of infiltration of rainfall into the soil
depends primarily on the intensity of the rainfall.
5. A moderate rainstorm will produce little runoff,
even if it rains for a long period of time.
6. As soil permeability decreases, surface
runoff increases.
7. Clay soils are usually less permeable than sandy
soils.
8. Increased compaction, resulting from construction
activities, is likely to increase soil permeability.
3-27
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Questions 5
True or false.
1. The steepness of the slope and the total length
of the slope influence the speed of the runoff.
2. The roughness of the surface affects the rate
of runoff.
3 _ Vegetation slows the flow of runoff and increases
the infiltration.
Vegetation improves the ability of the soil to
_
absorb water by providing organic matter on the surface
and in the soil.
5> _ Vegetation decreases the ability of the soil to
absorb water, by loosening the soil.
6. _ Plants remove water from the soil, thus de-
creasing infiltration.
3-28
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Questions 6
Fill in the blanks.
1. With modern equipment we can remove the vegetation from
vast areas, but by so doing, we may greatly increase the
amount of and resultant
2. Making areas of the soil impervious to water, by con-
structing pavements, buildings, and storm drainage
systems, increases the amount of .
3. management is one very important
means of controlling the amount and speed of runoff.
4. The speed of water influences its force.
5. A is the total ground area which
contributes surface water runoff to a given point.
6. The factors which affect the amount of precipitation
which will become runoff are intensity and total quantity
of rainfall, the of the soil, and its
surface , as well as the
of the area
velocity increases as slopes become
longer, steeper and smoother, and as drainage patterns
become straighter.
3-29
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EROSION AND SEDIMENT CONTROL
EROSION AND SEDIMENTATION
WORKBOOK
-------
CONTENT
I INTRODUCTION
II EROSION DEFINED
III NATURAL OR GEOLOGIC
IV ACCELERATED EROSION
A. Causes
B. Contributing Factors
C. Major Categories
1. Overland
2. Stream Channel
3. Shore
4. Wind
V OVERLAND EROSION
A. Sheet
B. Rill
C. Gully
VI PHYSICAL FACTORS AFFECTING EROSION
A. Climate
B. Vegetation
C. Soil
D. Length and Steepness of Slope
4-1
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VII SEDIMENTATION
A. Sedimentation Defined
B. Sediment Pollution
C. The Process
1. Transport of Sediment
2. Deposition of Sediment
D. Physical Factors
1. Characteristics of Flow
2. Nature of Particles
3. Nature of Fluid
VIII SOIL LOSS MEASUREMENTS
A. Universal Soil Loss Equation
B. -Stream Gaging
C. Sediment Sampling
IX REVIEW QUIZ
4-2
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I INTRODUCTION
A. Erosion and Sedimentation is the process whereby
soil particles are detached from the ground surface,
transported, and deposited.
1. This is a combination of two problems: erosion and
sedimentation.
2. These processes are interrelated, but they cause
different types of environmental damage-
II EROSION
A. Definition. Erosion is the process by which the land
surface is worn away by the action of wind, water, ice
or gravity.
Ill NATURAL OR GEOLOGIC EROSION
A. It is the action of the wind, water, ice and gravity
in wearing away rock to form soil and shape the ground
surface.
B. Except for some stream and shore erosion, it is a rela-
tively slow process, continually taking place.
C. This type of erosion is reported to produce about 30
percent of all sediment in the United States.
IV ACCELERATED EROSION
By accelerated, we mean a speeding up of erosion.
Whenever we destroy the natural vegetation or alter
the contour of the ground without providing some sort
of compensation, we increase the rate of erosion.
4-3
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This type of erosion is reported to account for about
70 percent of all sediment generated in this country.
A. Causes of Accelerated Erosion
1. Farming and construction are the principal causes
of accelerated erosion. These activities radi-
cally upset the delicate balance that nature has
developed between rainfall and runoff.
B. Contributing Factors to Erosion in Urbanizing Areas
1. The destruction of natural vegetation.
2. The removal of organic matter from the ground
surface.
3. Reshaping of the ground contour.
4. Exposure of subsoils during construction.
5. The placement of impermeable features like
paving and rooftops on the soil.
All of these factors increase runoff and in turn
increase
- the rate of erosion from the land surface.
- the rate of stream channel erosion.
- the amount of sediment that enters the waterways.
4-4
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C. Major Categories of Erosion
1. Overland Erosion
a. It occurs on denuded slopes above the natural
waterways as a result of raindrop splash and runoff.
b. It is the largest source of sediment during
construction operations.
c. It includes such types of erosion as sheet,
rill and gully.
2. Stream Channel Erosion
a. It occurs in intermittent or permanent waterways.
b. It is brought on by
increased runoff from urbanizing areas
the removal of natural vegetation along
the waterway
channel alterations as a result of construction
activities.
c. It includes both streambank and streambed erosion.
di Clear water may increase this kind of erosion.
3. Shore Erosion
a. It occurs along bodies of water as a result
of the impact of waves against a shore line
and is one shore erosion process.
b. Erosion by littoral currents, the movement of water along
the shore line is another process.
c. Accelerated shore erosion is brought on by man's
activities. They include:
(1) the destruction of natural vegetation along the
shoreline.
4-5
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(2) construction encroachment onto the shoreline.
(3) the generation of waves as a result of boating
activity.
d. It is severe in highly-developed areas found
in the coastal regions of the country and along
the Great Lakes.
4. Wind Erosion
a. In most urbanizing areas, because of obstructions to wine
abundant soil moisture, and vegetation, wind erosion does not
constitite as serious an environmental threat as
water erosion.
b. In an urbanizing area, the most damaging aspect
of wind erosion is dust. It causes a traffic
hazard, adds to cleaning costs, and equipment
maintenance and blights the appearance of the
structures.
V OVERLAND EROSION
A. Sheet Erosion -- It is the removal of a fairly uniform
layer of soil from the land surface as a result of
raindrop splash and runoff.
1. Raindrop splash is the impact of raindrops on the soil
surface. The splash detaches soil particles and
forms a muddy slick on the soil surface, which
is often referred to as "puddling." The magni-
tude of soil loss resulting from raindrop splash can
best be seen on a gravelly or stoney soil.
4-6
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2- Runoff carries away soil particles detached by
raindrop splash, and the flowing water detaches
additional soil.
B. Rill Erosion. It is caused when runoff is heavy and
water concentrates in rivulets.
1. It is evidenced by the development of small grooves
spaced fairly uniformly along the slope.
2. Individual rills range in depth and width up to
about one foot and reflect a tremendous loss of
soil.
3. If rilling is not corrected immediately, it may
develop into gully erosion.
4. It can be obliterated by normal tillage practices,
that is, plowing or discing and harrowing.
C. Gully Erosion.
1. Like rills, gullies are also grooves washed into
the soil.
2. The greater depth of erosion makes the distinction between
rills and gullies.
3. A gully can not be covered over by normal tillage
practices.
4. All gullies do not represent the culmination of
unchecked rill erosion. Improperly designed, con-
structed, or protected diversion structures, in
which runoff is concentrated, may cause gullying
first rain. The improper disposal of concen-
trated runoff from a development may also
cause serious gully erosion.
4-7
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c. Temperature influences the type of precipitation
that occurs.
(1) Falling snow does not erode.
(2) Heavy snow melts in the spring can cause
considerable runoff damage.
d. It is related to the amount of organic matter
which collects on the ground surface
(1) The warmer the climate the thinner the
organic cover.
(2) Organic matter protects the soil by
shielding it from the impact of falling
rain forming more stable soil aggregates and by soaking
up rainfall that would otherwise become runoff.
B. Vegetation is one of the more important factors
influencing soil erosion.
1. A good cover of vegetation
a. shields the soil from the impact of raindrops.
b. binds the soil together to protect against
runoff.
c. provides organic matter.
d. slows runoff velocities.
2. On a graded slope, the condition of the installed
vegetation will determine whether or not erosion
will be stopped or only slightly halted.
3. A dense, robust, cover of vegetation is one of the
best protections against soil erosion.
.C. Soil properties have a major bearing on erodibility.
4-8
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VI PHYSICAL FACTORS AFFECTING EROSION
A. Climate - The amount, intensity, and frequency of rain-
fall, as well as temperature, have a major influence on
erosion.
1. Rainfall Factors
a. Intensity - the rate at which the rain falls.
It is measured in inches of water falling in an
hour of time.
b. Infiltration Rate - the rate that water is
absorbed into the soil. It is also measured
in inches per hour.
c. Frequency of Rainfa.ll - the number of separate
rainfall events occurring during a period of
time. During periods of frequent rainfalls a
greater percentage of the rainfall will become
runoff. This is the result of soil moisture.
As the moisture content of the soil increases,
its ability to absorb water decreases.
2. Temperature is another part of climate influencing
erosion.
a. Frozen soil is highly resistant to erosion.
b. Rapid thawing brought on by warm rains can lead
to serious erosion.
c. Freezing and thawing action during winter weather lessens
the soil surface and increases the susceptibility to
erosion.
4-9
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1. Soil Properties influencing Erodibility.
b. Texture
It refers to the size of the soil particles.
Soils having high concentrations of silt
and fine sand, as well as those containing
highly expansive clay materials are most
susceptible to erosion from raindrop splash
and runoff.
- coarse sands resist erosion.
c. Structure
influences a soil's credibility
refers to the arrangement of the soil parti-
cles .
influences both the ability of the soil to
absorb water and its physical resistance to
erosion.
(1) Cohesion
- has a significant effect on the structure
of a soil.
- refers to the binding force between soil
particles.
- When moist, the individual soil particles
in a cohesive soil cling together to form
a doughy consistency. Clay soils fall in
this category.
- A sandy soil with a clay binder is usually
4-10
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relatively resistant to erosion, as are
most other soils containing significant
amounts of clay.
EXCEPTIONS -- soils containing highly ex-
pansive clays like bentonite. These soils
can be highly erodible.
When rapid expansion occurs on a natural
clay soil surface, a soft and soupy film
develops that is highly susceptible to erosion.
(2) Topsoil -- The presence of organic material
in a soil also has an effect on soil struc-
ture.
- In clay soils, it loosens the structure
and allows more water to infiltrate.
- In granular-structured sand or silt soils,
it tends to bind the soil into a mass that
is more resistant to erosion.
- In all cases, it absorbs water and thus
stores more water for plant use.
D. Length and Steepness of Slope is another major
factor affecting soil erosion.
1. Length of Slope
- when runoff occurs on long slopes the soil lying
at the base of the slope, over which all of the
runoff must pass, is subjected to severe erosion.
To avoid this problem, long slopes are often
4-11
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broken up so that they function as a series of
short slopes rather than one long slope. This is
accomplished by using various runoff control
structures including diversions, diversion
dikes, and benches. (these structures function
to intercept runoff and thereby prevent it from
flowing over the lower slope.)
2. Steepness of Slope may be expressed in percent.
(a) a 10% slope would indicate a IG-foot vertical
change for every 100 feet of horizontal distance.
(b) Slope steepness, surface roughness, and the
amount and intensity of rainfall are all factors
affecting the speed at which runoff flows
down a slope. The steeper the slope, the faster
the water will flow, and the faster it flows,
the greater will be its ability to remove soil
particles from the slope.
VII SEDIMENTATION
A. Definition - Sedimentation is the deposition of detached
soil particles.
B. Sed.iment Pollution causes damage to natural waters
by reducing the quality of water itself and reducing
the quality of the organism or wildlife habitat the water
flows through.
4-12
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It affects man be increasing flooding, damaging water supplies,
destroying recreational facilities, and increasing maintenance
costs. Some sediment may benefit organisms & nourish beaches
& other shorelines.
C. Minor changes in stream flow alter whether transport of sediment
and deposition of sediment occurs. These parts are so closely
interrelated that the same set of physical factors determine
whether sediment is transported or deposited.
1. Transport of Sediment is divided into two parts.
a. Suspended Sediment is the smaller particles that are
actually carried and supported by the water itself.
b. Bedload Sediment is the larger soil particles that
slide, roll, or bounce along the channel bottom.
D. Physical Factors Affecting Sedimentation - The interactions
of. these factors will determine how sediment is transported and
deposited.
1, Characteristics of Flow relates mainly to the velocity
and turbulence of the moving water.
a. The greater the velocity and turbulence of flow, the
greater will be the ability to carry sediment transported
in suspension and as bedload.
b. The lesser the velocity and turbulence of flow, the
greater will be the chances of sediment deposited.
4-13
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2. Nature of the Particles relates to the
size, shape and density of the particles in the
water.
a. Smaller, lighter particles are more easily
transported.
b. Larger, heavier particles are harder to trans-
port and thus are more easily deposited.
3. Nature of the Fluid relates to the density of
the fluid the particles are located in. Due to
its density, water has a certain ability to
"hold" particles and keep them from neing deposited.
VIII SOIL LOSS MEASUREMENTS
A. Universal Soil Loss Equation (A=RKLSCP) is a tool that
provides an approximate measurement of the po-
tential erosion that may occur at the site during
development. This equation is based on experiment
and observation and takes a number of factors into
consideration in arriving at a measurement of the
average annual soil loss from sheet and rill erosion.
1. "R" is the rainfall erosion factor and takes into
account the characteristics of rainfall in the
area of the site.
2. "K" is a measure of the erodibility of the soil
at the site.
3. "L" takes into account the influence of slope
length on erosion potential.
4. "S" is the slope steepness factor and accounts
4-14
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for the influence of slope steepness on
er edibility .
5. "C" the cropping-management and cover factor takes
into account soil cover and vegetative
erosion control
6. "P" is the erosion control practice factor
that accounts for the structural erosion con-
trol practice used on the site.
The product of multiplying all the factors toget-
her (A = R x K x LS x C x P) is the average
amount of potential soil loss in tons of sediment
per acre per year caused by sheet and rill ero-
sion.
B. Stream Gaging
1 . - Ihis is used to measure the rate of flow of a stream.
2 . - The device frequently used is a standard weir.
3. - For more detailed hydrologic information, a
rain gage is installed to measure the amount
of rainfall in the watershed.
C . Sediment Sampling
1. - It is used to measure the amount of sediment
moving in a stream.
2. - Sediment samples are often collected by hand
to measure the sediment load in the stream.
3 . - Automatic samplers are used to collect samples
at staggered time intervals throughout a
significant rainfall event, whether it occurs
during the day or night.
4-15
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QUESTIONS 1
Fill in the blanks
1. is the process by which the land surface
is worn away by the action of wind, water, ice or gravity.
2. Natural or erosion is a relatively slow
process, continually taking place.
3. erosion is reported to account for about
70 percent of all sediment generated in this country.
4. Farming and are the principal causes of
erosion.
5. The destruction of natural v and the reshaping
of the ground are contributing factors to erosion in urban-
izing areas.
4-16
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True or False
1. Overland erosion occurs on denuded slopes above
the natural drainageways as a result of rain
splash and runoff.
2. Wind erosion is the largest source of sediment
during construction operations.
3. Stream Channel erosion includes both streambank
and streambed erosion.
4. Littoral currents play a part in shore erosion.
5. Dust from wind erosion concentrates in waterways,
4-17
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QUESTIONS 3
Multiple Choice
1. Which of the following are types of overland erosion?
(a) sheet erosion (d) shore erosion
(b) rill erosion (e) a + b + c
(c) gully erosion (f) a + b + d
2. Sheet erosion is the removal of a fairly uniform layer of
soil from the land surface as a result of .
(a) rill and gully (d) rill and rainsplash
(b) rainsplash and rill (e) gully and runoff
(c) rainsplash and runoff
3. If rilling is not corrected immediately, it may develop
into erosion.
(a) sheet (c) shore (e) all of the above
(b) gully (d) stream channel
4. The distinguishing difference between rills and gullies is
(a) depth (c) weight (e) none of the above
(b) length (d) volume
4-18
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QUESTIONS 4
Fill in the Blanks
1. T can be related to erosion in several ways.
2. The amount, intensity and frequency of r have
a major influence on erosion.
3. During periods of frequent rainfalls a greater percentage
of the rainfall will become r .
4. As the m c of the soil increases,
its ability to absorb water decreases if other conditions are constant.
5 . 0 m on the soil surface protects
the soil bv shielding it from the impact of falling rain.
4-19
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True or False
_1. On a graded slope, the condition of the installed
vegetation will determine whether or not erosion will
be stopped or only reduced.
_2. Soil type has a major bearing on erodibility.
3. Cohesion refers to the binding force between soil particles
4. Typical beach sand has cohesion.
5. The presence of organic material in a soil has no
effect on soil structure.
4-20
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Multiple Choice
1. In our discussion of length of slope we saw that long
slopes were converted to a series of short slopes by
using various runoff control structures like
(a) diversions (d) both a & b
(b) diversion dikes (e) both a & c
(c) benches (f) a & b & c
2. A 10% slope would indicate
(a) a 10-foot horizontal change for every 100 feet of
vertical distance.
(b) a 10-foot vertical change for every 10 feet of hor-
izontal distance.
(c) a 100-foot vertical change for every 10 feet of
horizontal distance.
(d) a 5-foot vertical change for every ^° feet of
horizontal distance.
3. Slope steepness, surface roughness, and the amount and
intensity of rainfall are factors controlling
(a) amount of water falling on a slope .
(b) speed at which a rill erodes.
(c) amount of rain in a watershed .
(d) soil erosion.
4-21
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QUESTIONS 7
Fill in the blanks
1- § is the deposition of detached soil particles.
r> causes damages to natural
waters by reducing the quality of water itself and by
reducing the quality of the habitat the water flows through.
3. While being t sediment is divided into two types:
suspended sediment and bedload sediment.
4. The factors affecting sedimentation are so closely interrelated
that the same set of p f determine
whether sediment is t or d •
4-22
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True or False
_1. The interaction of the physical factors affecting
sedimentation will determine whether sediment is trans-
ported or deposited.
_2. Characteristics of flow relates mainly to the
velocity and turbulence of the moving water.
_3. Small light particles are harder to transport than
larger heavier particles.
_4 . Nature of the fluid relates mainly to the density of the
fluid the particles are located in.
4-23
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Fill in the blanks
The Universal Soil Loss Equation
A = RKLSCP
1. " " is the measure of credibility of the soil at the site
2. " " is the rainfall erosion factor.
3. " " takes into account the influence of slope length on
erosion potential.
4. " " is the erosion control practice factor.
5. This equation is used to measure the soil loss caused by
s and r erosion.
4-24
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QUESTIONS 1O
True or False
1. Stream gaging is used to measure the amount of sediment
entering a waterway.
2. A standard weir may be used in stream gaging.
3. Hand methods are often employed to collect sediment
samples.
4. Automatic samplers are used to collect samples at
staggered time intervals.
4-2b
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QUESTIONS 11
REVIEW QUIZ
1. E is the process by which the land sur-
face is worn away by the action of wind, water, ice
or gravity.
2. N ^ or g erosion is the natural action
of the" wind, water, ice and gravity in wearing away
rock to form soil and shape the ground surface.
3. Except for some stream and shore erosion, g
erosion is a relatively slow process, continually
taking place.
4 • By a , we mean erosion in excess of geologic erosion.
5. Whenever we destroy the natural vegetation or alter
the contour of the ground without providing some sort
of compensation, we greatly i the rate of
erosion.
6. About 70% of all the sediment generated in this coun-
try is caused by a erosion.
7. The principal causes of accelerated erosion are
f and c . These activities
radically upset the delicate balance that nature has
developed between r and r .
8. U areas are least able to accept the
damages resulting from soil erosion.
4-26
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9. The destruction of natural vegetation, reshaping of the
ground contour, and the exposure of subsoils during con-
struction are c factors to erosion in urban areas.
10. _S erosion occurs on denuded slopes above the
natural streams as a result of raindrop splash and runoff.
11. Accelerated s c erosion occurs in intermittent
or permanent streams. It is brought on by increased
from urbanizing areas, the r of
natural vegetation along the waterway, and c
alterations as a result of c _ activities.
12. S _ erosion occurs along large bodies of water
as a result of the impact of waves against a shore line
i _ currents, the movement of water along
the shoreline, also may cause shore erosion.
13 . In many urbanizing areas w _ erosion does not con-
stitute as serious an environmental threat as water erosion.
14 . S _ erosion is the removal of a fairly uniform
layer of soil from the land surface as a result of rain
splash and runoff.
15. R _ is caused when runoff is heavy and water
concentrates in rivulets.
16. D _ is the distinction between rills and gullies.
17. I _ is the rate at which the rain falls.
18. I _ is the rate at which water is absorbed into
the soil.
4-27
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19. 0 _ m _ _ protects the soil by shield-
ing it from the impact of falling rain and also by
soaking up rainfall that would otherwise become run-
off.
20. A dense, robust cover of v _ is one of the
best protections against soil erosion.
21. TWO soil properties influencing erodibility are
t
22. C _ _ refers to the binding force between
soil particles.
23. A 15i-foot vertical change for every 75 feet of hor-
izontal distance would be called a _ percent
slope.
24. S _ is the -deposition of transported soil particles.
25. S p affects man by in-
creasing maintenance costs.
26. While in transport sediment is divided into two
types s sediment and b sedi-
ment.
27. The soil loss equation is a tool
that provides an approximation of the
potential erosion that may occur at the site during
construction.
4-28
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28. The letter is a measure of soil erodibility
of the soil at the site.
29, The letter takes into account the influence
of slope length on erosion potential.
30. The letter C is the c and m
factor that takes into account vegetative and other soil
cover control practices.
31. G refers to the measurement of the
flow of water in a stream channel.
32. To measure the sediment load in a streamf
s are taken.
4-29
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EROSION AND SEDIMENT CONTROL
PLANT MATERIALS
WORKBOOK
-------
CONTENT
I INTRODUCTION TO PLANT MATERIALS
A. Usefulness of "Standards and Specifications"
B. Importance of Plant Materials
II CLASSIFICATION OF PLANT MATERIALS
A. Desirable characteristics of plants.
B. Terms used to Classify Plants
1. Annuals and Perennials
2. Evergreen and Deciduous Plant Materials
III BASIC STRUCTURE OF PLANTS
A. Root, Stem, and Crown
B. Structure and Function of Roots
1. Functions
2. Spread of Root System
3. Tap vs Fibrous Roots
C. Stem
D. Crown
IV GRASSES AND LEGUMES
A. Grass Family
1. Variations in characteristics.
2. Methods of Establishment
3. Grasses as Ground Cover
4. Use with MONOslabs
5. Use in Waterways
6. Rhizominous, Stoloniferous, and Bunch
5-1
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B. Legumes
V PLANNING FOR THE USE OF PLANT MATERIALS
A. Site Investigation
B. Environmental Factors Affect Different Types Differenl
1. Need for Determination of Environmental Factors
2. Climatic Conditions
3. Condition of Soil
4. Seasonal High Water Tables
5. pH
6. Tidal Banks and Shorelines
7. Literature to Consult
VI MAINTENANCE
A. Usually Required
B. Selection of Plant Materials
C. Control of Insect Damage
D. Prevention of Plant Starvation
1. Causes of Plant Starvation
2. Plant Nutrients
3. Fertilization
Note: The plant materials discussed in this and following chapters
are the better plants for the Mid-Atlantic region. They are
intended as example and not nationwide application.
5-2
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INTRODUCTION TO PLANT MATERIALS
A. An erosion and sediment control specialist has to
know how to use plant materials to control soil
erosion. Certain publications can help guide you
in their use. The publication "Standards and
Specifications for Soil Erosion and Sediment
Control in Developing Areas" is particularly
useful.
1. To use a publication of this sort, you have
to know about the common categories and
types of plant materials, their physical
characteristics in relation to erosion and
sediment control, the factors you must con-
sider in selecting plant materials, and the
essential requirements you must meet, to
insure that the plants grow vigorously.
B. Importance of Plant Materials
1. Plant materials help control soil erosion,
sedimentation, and stormwater runoff in at
least four important ways.
a. First, they form a protective cover which
shields the surface of the soil from the
impact of raindrops.
b. The second beneficial effect of a good plant
cover is that the stems, foliage, and debris
5-3
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slow the flow of water along the surface
of the soil.
c. The third important way in which a good
plant cover protects against soil erosion
is by holding soil in place with its roots.
d. Fourth, plants provide organic materials
for the soil as the surface litter and root
material decays, through the action of soil
builders, such as microorganisms and
earthworms. This organic material con-
serves moisture and provides a better
environment for plant growth, it usually speeds
up soil infiltration rates.
II CLASSIFICATION OF PLANT MATERIALS
A. All plants are useful in erosion control, but some
plants, because of their physical structure and
their adaptability to the physical and climatic
conditions at a given site, are more desirable
than others. The best plant is the one that will
provide the necessary control, and will need the
least maintenance.
B. In order to choose the proper plants, you must under-
stand some of the terms used to describe them.
1. Plants used for erosion
control are grouped into annuals and
perennials.
5-4
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a. An annual completes its entire life
cycle in one growing season. For
this reason, some annuals are useful for
providing quick, temporary soil
stabilization.
b. Perennials, in contrast to annuals,
live for many seasons.
1. Examples of perennials include trees,
shrubs, vines and many grasses.
2. Perennials used in stabilizing soil
include long-lived legumes such as
birdsfoot trefoil, bermudagrass,
vines, such as honeysuckle, and ground
covers, including ivy, and lily turf.
3. Because of their ability to control
soil erosion year-round, and because
of their long lifespan, perennials are
used for long-term or permanent soil
stabilization.
2. There are both evergreen and deciduous plant
materials.
a. Evergreens keep their foliage alive through-
out the year, despite normal seasonal changes
in the climate.
1. Evergreens include ground covers, vines,
shrubs, and trees.
5-5
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2. Periwinkle is an example of an evergreen
ground cover.
3. Ivy is an evergreen vine.
4. Creeping juniper is an evergreen shrub
which is often used as a ground cover.
5. Evergreen trees include those with
needle-like leaves, such as white pine,
and those with broad leaves, such as
holly.
b. In contrast to evergreens, deciduous plants
shed their foliage at a given season, usually
fall.
1. Examples of deciduous plants include
crownvetch, which is used as a
ground cover, kudzu, a vine, forsythia,
a shrub, and black locust, a deciduous
tree.
Ill BASIC STRUCTURE OF PLANTS
A. The basic structure of a plant consists of the roots,
the stem, and the crown.
B. The roots, in addition to serving the plant, hold soil
in place and aid the infiltration of water into the
soil.
1. Depending on the type of plant, roots vary con-
siderably in size, physical makeup, and density.
2. The spread of a tree's root system is normally
equivalent to the spread of its crown.
5-6
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3. Roots are grouped as either tap or fibrous.
a. A tap root grows vertically, downward.
Secondary roots branch out from the tap
root.
b. A fibrous root system, on the other hand,
does not have a main root. Instead, many
roots radiate downward and outward from
the base of the stem.
1. Fibrous root systems control soil
erosion and runoff better than tap
root systems because these roots bind
the soil tightly in place and form a
spongy layer beneath the ground
surface, which resists compaction
and absorbs water.
C. Stems vary considerably in physical appearance,
strength, and 'ability to aid in controlling soil
erosion.
1. Plant stems can be classified as either herbaceous
or woody.
a. Herbaceous stems are soft and green. They
have virtually no tough, woody tissue.
b. Woody stems, on the other hand, are thicker,
harder, and stronger.
1. Plants may have either single or
multistems. The multistems are most
beneficial for erosion and sediment
control purposes.
5-7
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2. Multistemmed plants provide a dense
canopy of foliage that protects the
surface of the soil from the impact
of falling raindrops. Examples in-
clude the bristly locust and sumac.
3. Still other plants have stems that
emerge from along the trunk roots;
the roots run under the surface of the ground.
4. An example of a plant with stems that
emerge from the roots is the black
locust.
D. The branches and foliage of plants such as trees and
shrubs are referred to as the "crown." The "crown"
can also refer to the branching foliage of many
herbaceous plants.
1. The crown is the manufacturing center of the
plant. Here minerals and water, brought up
from the roots, along with carbon dioxide from
the atmosphere, utilizing energy from sunlight,
are converted into food and energy needed for
the growth and maintenance of the plant.
2. In addition to supplying nourishment for the
plants, the crowns of plants such as trees
and shrubs aid in controlling soil erosion.
Crowns protect the soil from the full impact
5-8
-------
of raindrops, especially when the crowns form
a thick canopy.
3. The crowns of trees, shrubs, and other plants
help control wind erosion and moderate extreme
changes in temperature.
4 . Crowns produce leaves which form a mulch; this protects
the surface of the soil from erosion, provides
soil nutrients, and assists in the development
of desirable tilth of the soil, that is, its structure.
IV GRASSES AND LEGUMES
A. One of the most important families of plants, for
stabilization, is the grass family. Grasses are by
far the most widely used materials for vegetating
critical areas.
1. There are many varieties of grasses, each
differing in physical structure and
adaptability to climatic conditions.
2. The varieties differ, as well, in the way they
should be established: some are established
by seeding, some by sprigging, some by sodding,
and some as clumps, or culms.
3. Properly managed, selected grasses will form a close,
dense ground cover. Many grasses are able to
bear fairly heavy traffic and continuous
close mowing. They are therefore useful for
vegetating roadway shoulders and medians.
5-9
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4. Where some light traffic is expected, such as in parking
lots used only for overflow parking, grasses can be used
alone or in conjunction with a reinforcement, such as MONOslabs
or checker blocks.
5. Certain grasses are also widely used for stabilizing waterways.
6. According to the way they grow, grasses commonly used for soil
stabilization can be classified in the following three
categories: rhizomitous, stoloniferous, and bunch grasses.
a. Rhizonitous and stoloniferous grasses spread by producing
"runners" that extend out from the main plant.
1. Rhizomes are runners below the surface, which spread
out and produce new runners. American beachgrass
spreads in this way. Stolons are runners on top of
the ground which roots at many points along its
length. Bermudagrass spreads this way.
2. When properly maintained, these rhizonitous and
stoloniferous grasses spread rapidly to form a
dense cover. For this reason, they are normally used
on lawns, recreational areas, and waterways.
Examples include bermudagrass and Kentucky bluegrass.
3. Many of the grasses used to stabilize shores
and waterways spread by producing runners or
rhizomes. Examples
5-10
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include reed canarygrass, beachgrass,
and smooth cordgrass.
b. As opposed to rhizomitous and stoloniferous
grasses, bunch grasses do not spread by
means of runners. Instead, the blades
radiate upward and outward from the surface
of the ground, thus forming a bunch.
1. Because Kentucky 31 tall fescue adapts
to a wide range of climatic conditions,
it is an example of a popular bunch grass for
stabilizing critical areas.
2. When an area has been heavily seeded
with selected bunch grasses, a dense cover
will form, but it will need some
maintenance.
B. Legumes are primarily used to stabilize slopes that
are hard to maintain, because legumes require little
maintenance.
1. Legumes not only provide an excellent cover,
they also help maintain grasses, when the two
materials are planted together. The legumes
help the grass by converting atmospheric
nitrogen, which cannot be used by grasses,
into forms of nitrogen, which are available
for plant use.
2. Legumes include a wide variety of plants, from
large trees, such as the locust, to crown vetch
5-11
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a small herbaceous plant.
3. A common characteristic of all legumes is that
their seeds develop in pods.
4. Crownvetch is a legume that is widely used to
form a low-iraintenance ground cover on slopes
that may be mostly subsoil.
5. Sericea lespedeza is another legume widely
used for stabilizing critical slopes. It
holds the soil on highly critical slopes
because it has deep roots, and it can
survive on droughty poor, acid soils.
6. On mass-graded developments, where areas
may not be developed for one or more
growing seasons, Kentucky 31 tall fescue
and a legume are often used as a semi-
permanent cover.
7. It is becoming more common to seed legumes and
grasses which provide fast cover with slow-
growing native herbaceous and woody plants,
such as shrubs, vines, and trees, to stabilize
critical areas. This mixture provides a long-term
cover that requires little maintenance. As
some species of plants lose their vigor, other
longer-lived types succeed them.
V PLANNING FOR THE USE OF PLANT MATERIALS
A. A site investigation is required to provide a long-
term, low-maintenance cover, that will adequately
5-12
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stabilize the soil. Developing an adequate plan
for revegetation includes selecting the proper
materials and developing a maintenance program.
B. At a given site, not all types of vegetation commonly
used for stabilization will perform satisfactorily.
Each type of plant differs in its ability to adapt
to a given set of environmental factors.
1. You must determine what the environmental
factors are for each site, and utilize these
findings in developing a plan for revegetating
a site.
2. Climatic conditions are a major factor to be
considered at each site before selecting the
plant materials to be used for stabilization.
a. In considering temperature and precipita-
tion, you must determine in which climatic
zone the site occurs, and then select those
types of plants which are known to grow
successfully in this zone.
b. Temperate regions have marked seasonal
changes in temperature and precipitation.
1. In such areas you must consider the
time of year during which you will be
planting.
5-13
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2. Plants such as weeping lovegrass and bermuda-
grass grow best during the summer
months, while Kentucky bluegrass
grows better during the cool and
moist fall and spring months.
c. Another climatic condition to consider is
exposure. On a highway running east and
west, for example, the two sides, if they
are both cuts or both fills, will differ
widely in the kinds of vegetation they can
support.
1. During most of the day, slopes facing
northward will be shaded, and therefore
more moist.
2. Slopes facing southward, on the other
hand, will be exposed to direct sunlight,
and will therefore tend to be more
droughty.
3. Sericea lespedeza and lovegrass would do
well on the slope facing southward.
4. On the slope that is shaded most of the
day, a grass that tolerates the shade,
such as creeping red fescue or Kentucky 31
tall fescue, will perform well.
3. You should also consider the condition of the
soil.
5-14
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a. Is the soil naturally fertile? Does it
contain an adequate supply of organic
material and essential nutrients? For
a reliable evaluation, have the soil tested.
b. Examine the soil to see if it may be droughty
at certain times of the year. Also check climatic
records for temperature and rainfall data.
c. Generally, droughty soils contain less than
30% fines, that is, the very small silt -
and clay-size particles which hold moisture.
Many sandy soils are droughty.
d. If you encounter a droughty soil, use plants
that are drought-resistant, such as weeping
lovegrass.
e. Excessively droughty soils may be improved
by adding organic mulches or topsoil. These
materials are commonly called "soil conditioners."
4. Seasonal high water tables may also present a
problem. Where the water table occurs near the
soil surface, the soil at the surface may be
wet during much of the year.
a. When this condition exists, you will have
to choose plant materials, such as reed
canarygrass, which tolerate wet soils.
5. Test the pH of the soil. The pH is a measure
of the alkalinity or acidity of a soil.
a. Soils with a pH of 7 are neutral;
those with a pH above 7 are
5-15
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alkaline, or basic, and those with a pH
below 7 are acidic.
6. Tidal banks and shorelines present special
problems. These include soil conditions, salt
spray, and strong winds.
a. Among the plant materials which may be used
in these areas are smooth cordgrass, American
beachgrass, and Tufcote bermudagrass.
b. The use of various plant materials depends
on the vegetative zone to be stabilized.
7. Before consulting the literature for the final
selection of plant materials, determine the
physical factors limiting the selection, and
the intended use of the site. One publication
you should definitely consult is "Standards and
Specifications for Soil Erosion and Sediment
Control in Developing Areas," Written by the Soil
Conservation Service for the Maryland Water Resources
Administration.
VI MAINTENANCE
A. Plant materials usually require maintenance.
B. Selection of Plant Materials.
1. Selecting good materials is a form of preventive
maintenance. To protect against plant disease,
you must insure that the seeds or vegetative
materials are free of diseases.
5-16
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2. See that seed and sod materials are properly
certified; only purchase them from approved
sources. Make sure other plant materials are
free from major diseases and insect infestation.
a. State certification is the best guarantee
of the purity of a variety. The State
Board of Agriculture analyzes and carefully
controls the weed-seed content, the inert
matter, and the contaminants.
C. Another important kind of maintenance is the control
of insect damage. The control of insect damage,
using approved pesticides and other means, is some-
times vital to the maintenance of vegetation used for
stabilization.
D. Another vital form of maintenance is the prevention
of plant starvation.
1. Plant starvation results either from excessive
competition for moisture and nutrients by
weeds or a nurse crop, or from a deficiency
of plant nutrients in the soil.
a. As with plant disease, the best defense
against a problem involving weeds is to
select good-quality seed or vegetative
material.
b. Be aware, when you use topsoil, that it
may contain noxious weed seed.
5-17 ,
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c. In some areas, herbicides may be an effective means
controlling weeds. Check with local weed control
specialists.
d. Mowing is another way to control weeds. Try to mow weeds
above the tops of desirable plants.
2. Plant Nutrients
a. Even the desirable plant materials will eventually deplete
the available supply of plant nutrients.
b. Plant materials established on subsoils rather than topsoil
will usually require more frequent applications of fertilizer
and lime if required.
c. The three major nutrients are nitrogen, potassium, and
phosphorus. All of these major plant nutrients have an
important influence on the development of a plant.
d. Nitrogen tends to encourage the above ground growth of plants.
1. Nitrogen also helps the plant regulate its use of
potassium and phosphorus.
2. A deficiency of nitrogen will cause stunted growth
and restricted root development.
3. Nitrogen deficiency will also make the plant more
susceptivle to attack by diseases and insects. If
the foliage of the plant yellows, it often means that
the plant is deficient in nitrogen.
4. Inoculated legumes will not usually show nitrogen
deficiency after plants are old enough to fix nitrogen.
5-18
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e. Phosphorus plays an important role in the
ability of a plant to assimilate other
nutrients.
1. It is also essential for the full de-
velopment of sturdy, healthy roots and
crown.
2. A purplish color that develops on the
leaves and the new growth of a plant
often indicates a phosphorus deficiency.
f. Potassium is also essential for the growth
of a plant.
1. Potassium is furnished by potash.
2. Potassium, along with phosphorus, has
an important role in the development
of the root system of a plant.
3. Potassium is essential for
manufacturing and storing plant
food.
4. In addition, potassium increases the
resistance of a plant to disease.
5. A dry, scorched appearance in the
leaves of a plant may indicate a
potassium deficiency.
Fertilization
a. To determine whether a soil will support a
particular vegetative cover, you must have
certain chemical tests made. State universities,
5-19
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in cooperation with local county
agricultural extension agents, make low
cost laboratory testing available.
b. Fertilizers are marketed in a variety of
combinations of available nitrogen,
phosphorus, and potassium. The per-
centages of these available nutrients
are labeled on the container. For
example, an 80-pound bag of fertilizer
labeled 10-6-4 would contain 10 percent,
or 8 pounds of available nitrogen, 6
percent, or 4.8 pounds, of available
phosphorus, and 4 percent, or 3.2 pounds,
of available potassium.
c. For acid Soils, lime is also essential for
maintaining vigorous growth.
1. Lime (calcium carbonate) is primarily used to
neutralize acid soil, and to make many
of the essential nutrients more available
to plants. Legumes require more lime than grasses.
2. The lime also provides nutrients essential
for plants, such as calcium and magnesium.
Dolomitic lime is preferred, because it
supplies magnesium as well as calcium.
3. In addition, lime increases the ability
of certain tight, clayey soils to hold
moisture, by improving the structure.
5-20
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Questions 1
True or False.
1. Plant materials of fer excellent protection against
the ravages of soil erosion.
2. Plant materials generally allow falling raindrops
to strike the surface of the earth, with their full
impact.
3. The impact of a raindrop striking the bare surface
of the soil can dislodge soil particles. These
particles are thrown into suspension, and carried
away by the runoff.
4. Sediment, in suspension, passes as easily through
grass as the water itself.
5. Plants also protect against soil erosion by
holding soil in place with their roots.
6. Roots help prevent water from infiltrating into
the ground.
7. Roots benefit the soil by aerating it.
5-21
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Questions 2
Circle the correct answer or answers.
1. All plants are useful in erosion control, but some plants
are more desirable than others because of
a. their physical structure
b. their weed-seed content
c. their adaptability to the physical and climatic
conditions at a site
d. their ability to grow on soils low in nitrogen
2. The best plant is
a. the one that requires the most nutrients
b. the one that will provide the necessary erosion control
c. the one that will need the least maintenance
d. the one that is most susceptible to damage by insects
3. The most common ways of grouping plants are
a. by the color of their flowers
b. by cost
c. by their lifespans
d. by their physical characteristics
4. As for lifespans, plants used for erosion control are
grouped into
a. annuals and perennials
b. deciduous and evergreen
c. rhizominous, stoloniferous, and bunch
d. tap root and fibrous root
5-22
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5. An annual completes its growing season in
a. more than two years
b. two years
c. one growing season
6. Annuals used for permanent stabilization, because of their
ability to reseed themselves year after year, include
a. Korean lespedeza
b. millet and sudangrass
c. cereal grains
d. Kentucky 31 tall fescue
e. corn
7. Perennials used in stabilizing soil include
a. cereal grains
b. birdsfoot trefoil
c. long-lived grasses
d. millet and sudangrass
e. vines, such as honeysuckle
f. Korean lespedeza
g. ivy and lily turf
8. Evergreens
a. lose their leaves once a year, usually in the fall
b. keep their foliage alive throughout the year, despite normal
seasonal changes in climate
c. include cereal grains
d. include periwinkle and ivy
e. include creeping juniper, white pine, and holly
9. Deciduous plants
a. lose their leaves once a year, usually in the fall
b. keep their foliage alive throughout the year, despite normal
seasonal changes in the climate
c. include sericea lespedeza and kudzu
d. include periwinkle and ivy
e. include forsythia and black locust
5-23
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Questions 3
Fill in the blanks.
1. The spread of a tree's root system is normally equivalent
to the spread of its .
2. Roots are grouped as either or fibrous.
3. A root grows vertically, downward. Secondary
roots branch out from the root.
root systems control soil erosion and runoff
better than root systems.
5. An example of a plant with stems that emerge from the roots
is the .
6. The branches and foliage of plants such as trees and shrubs
are referred to as the .
7. The crowns of trees, shrubs, and other plants help control
wind erosion and moderate changes in .
8. Crowns also provide a i which protect the_
surface of the soil from erosion, provides soil nutrients, and assists in
the development of the til*h of the soil, that is, its structure.
5-24
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Questions 4
True or False.
1. Grasses play a relatively minor role in vegetating
stabilized areas.
2. There are many varieties of grasses, each differing
in physical structure and adaptability to climatic
conditions.
3. Some varieties of grasses are established by
seeding, some by sprigging, and some by clumps, or
culms.
4. Grasses are classified as bunch grasses and legumes,
5. Rhizomitous and stoloniferous grasses spread by
producing "runners" that extend out from the main
plant.
6. Kentucky bluegrass spreads by rhizomes.
7. Bunch grasses also spread by producing "runners,"
that extend out from the main plant.
8. Selected legumes can be used to stabilize slopes that
are hard to maintain ; some legumes require little
maintenance.
5-25
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Questions 5
Each of the following sentences contains one error. Write the
letter that corresponds to the incorrect word or phrase in the
blank provided.
Developing an adequate plan for revegetation includes
a site investigation, selecting the proper materials,
A B
little or no planning for a long-term, low-maintenance
C
cover, and developing a maintenance program.
C D
One of the major environmental factors which you must
investigate at each site before selecting plant
materials is climatic conditions; these include
temperature, pH, precipitation, and exposure to
ABC D
sunlight and wind.
D
Plants such as bermudagrass and weeping lovegrass grow best
during the hot summer months, and in the late fall,
A B
while Kentucky bluegrass grows better during the cool
C
and moist spring months and in the fall.
C D
5-26
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During most of the day, slopes facing northward
will be shaded and therefore more moist; slopes
AB
facing southward will be exposed to direct sunlight
C
and will therefore tend to be unlikely to support
D
vegetation.
D
Soil conditions you should consider before selecting
a plant material include fertility, the moisture content,
A B
and the exposure. (Exposure is important but it is a site
C condition.)
Generally droughty soils contain more than 25 to 30%
A
fines; many sandy soils are droughty, while most
A B C
clayey soils are not, but the best way to tell if a
C
soil is potentially droughty is to determine the
D
distribution of the various grain sizes in the
D
laboratory.
D
If you encounter a droughty soil, use plants that are
A
highly susceptible to drought, such as weeping lovegrass;
A B
these plants are able to regulate their consumption of
C
water, and they have deep roots, which penetrate below
C D
the droughty zone.
D
5-27
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Questions 6
Fill in the blanks.
Where the water table occurs near the soil surface, the
soil at the surface may be during much of
the year.
When this condition exists, you will have to choose plant
materials, such as , which tolerate
soils.
Test the of the soil. The is
a measure of the alkalinity or acidity of a soil.
is an example of a plant that tolerates
fairly acidic soil.
Among the plants which may be used on tidal banks and
along shorelines are and
Before consulting for the final
selection of plant materials, determine the physical
factors limiting the selection, and the intended use of
the site.
5-28
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Questions 7
Circle the correct answer or answers.
1. To protect against plant disease, you must
a. spray the plants with DDT
b. insure that the seeds or vegetative materials are free
of diseases
c. use applicable pesticides according to label instructions.
2. One way of protecting against plant diseases is
a. to see that seed and sod materials are properly certified
b. to make sure that the seed or sod materials contain a
sufficient percentage of inert filler
c. to make sure the soil does not contain any noxious sub-
stances, such as nitrogen
3. The control of insect damage can be legally achieved by
a. the use of DDT
b. planting a nurse crop, together with legumes
c. the use of approved pesticides and other means
4. Plant starvation results from
a. excessive competition for moisture and nutrients, by
weeds or a nurse crop
b. the use of certified turfgrass sod
c. a deficiency of plant nutrients, or soil moisture in the soil
5-29
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5. Weeds can usually be controlled by
a. the use of topsoil
b. the selection of a good quality seed or vegetative
material
c. herbicides
d. the use of disease free plant materials
e. mowing
6. The time required for desirable materials to deplete the
soil nutrients will vary depending on
a. the type of plant material
b. the certification of the seed and sod materials
c. the physical structure of the soil
d. the natural level of the nutrients in the soil
e. the intensity of precipitation
f. pH
5-30
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Questions 8
Each of the following statements contains one mistake. Write
the letter that corresponds to the incorrect phrase in the
blank provided.
1. Plants, in order to grow well, require sixteen
A
elements, or nutrients. However, the three major
A
nutrients are nitrogen, phosphorus, and calcium.
B ' C D
2. Nitrogen tends to moderate the growth of plants
A
above the ground; it gives the foliage a deep-green
A B
color. If the foliage of the plant yellows, it often
B C
means the plant is deficient in nitrogen.
C
3. Phosphorus plays an important role in the ability of
A
a plant to assimilate other nutrients. It is essential
A
for the full development of sturdy, healthy roots and
B
crown. A dry, scorched appearance in the leaves may
B C
indicate a deficiency of phosphorus.
5-31
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Potassium is furnished by legumes. Potassium has
A
an important role in the development of the root
B
system. Potassium is also essential for manufacturing
B C
and storing plant food. A dry, scorched appearance
C D
in the leaves may indicate a potassium deficiency.
D
An 80 pound bag of fertilizer labeled 1O-6-4 would
contain 10 percent, or 8 pounds of available nitrogen,
A
6 percent, or 4.8 pounds of available potassium, and
B
4 percent or 3.2 pounds of available potassium.
C
Lime is primarily used to supply magnesium, but it
A
also neutralizes acid soil, makes many of
B p
the essential nutrients more available to plants,
C
provides nutrients such as calcium, and increases the
D E
ability of certain tight, clayey soils to hold moisture.
E
5-32
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Questions 9
True or False.
1. Plants aid in controlling erosion by protecting
the soil from the direct impact of the falling
rain, by slowing the flow of water over the sur-
face of the ground, by holding the soil, and by
adding organic matter to the soil.
2. Annuals live for several years; they often flower
and produce seeds each year.
3. Plants with tap roots are more beneficial in con-
trolling soil erosion than those with fibrous roots.
4. Bunchgrasses are useful in controlling soil erosion,
while grasses with stolons or rhizomes are not.
5. Legumes are useful because selected legumes require little main-
tenance; some legumes can be used in areas which are hard
to maintain.
6. Legumes add nitrogen to the soil. Because of this
they are often used along with other plants.
7. In order to develop an adequate plan for revegetating
a graded area, it is usually sufficient to select the
proper plant materials.
5-33
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8. Environmental factors you should investigate
include temperature, precipitation, and exposure
to sun and wind.
9. It is usually unnecessary to investigate the
soil's pH.
10. Once plants have been established, they will
usually need no further attention.
11. The main plant nutrients present in fertilizers
are nitrogen, phosphorus, and potassium.
12. For soils too acid for plants being planted you should add
lime to the soil, before planting.
13. Legumes, when planted with grasses, help the grass
by converting atmospheric nitrogen into a form
useable by the plants.
14. Legumes include crown vetch, Korean lespedeza,
locust trees, and Sericea lespedeza.
15. It would be a serious error to seed legumes and
grasses, together with native herbaceous and
woody plants, such as shrubs, vines, and trees,
to stabilize veritical areas.
16. Soils with a pH of 7 are neutral.
17. Soils with a pH below 7 are basic.
5-34
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EROSION AND SEDIMENT CONTROL
CONTROL OF RUNOFF
DURING CONSTRUCTION
WORKBOOK
-------
I. INTRODUCTION
A. Definitions
1. Stormwater Runoff - rain that is not ab-
sorbed when it comes in contact with the
soil. This runoff may carry soil with it
The faster it travels, the more soil it can
erode and carry.
2• Sediment - soil that is transported by
runoff and deposited on the ground
surface or in waterways.
B. Factors that Increase Runoff
1. Grading during construction that destroys
natural vegetation - which is nature's
greatest runoff protection.
2. Construction changes the natural balance
of the land. Grading practices during
construction may turn gentle slopes into
steep slopes.
3. Construction covers large portions of soil
surface with roof and concrete or asphalt
pavement. (A 20% loss of soil area will
cause runoff to more than double during
heavy rainfall.)
6-1
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II. CONTROL OF RUNOFF - OVERVIEW
There are two ways to control runoff:
A. Decrease the amount of runoff by using special
grading ^practices that increase the detention and intake
of water into the soil.
B. Diversion is another method used to control
runoff. With a diversion structure, runoff
is intercepted and diverted to an area where
it will be absorbed or safely discharged.
III. SPECIAL GRADING PRACTICES
A. Preserving Vegetated Buffer Areas. Preserv-
ing a buffer zone above and below a graded
area will trap much of the rainfall before
it has a chance to erode and will filter run-
off from the graded area.
B. Staging - dividing a construction site into
different areas. With staging, grading and
stabilization are finished in one area be-
fore proceeding to the next. This limits the
amount of soil exposed to erosion at any
given time.
c- Surface Roughening - is an easy and economi-
cal method that simply creates an uneven or
bumpy condition on the soil surface. Horizon-
tal grooves tend to spread runoff over the
slope, slowing it down and allowing more of it
6-2
-------
to be absorbed by the soil. Scarification is one
way to roughen the soil surface. It is often
performed by back blading along a slope with the
teeth of a loading bucket mounted on a crawler
tractor. Roughening produces a soil surface
very suitable for the growth of vegetation.
IV. DIVERSION STRUCTURES
A. Temporary and Permanent
Diversion structures are built to intercept
and divert runoff at a safe or non-erosive
velocity. Temporary structures are designed only
for the construction period, while permanent
structures are built to remain both during
and after construction.
B. Interceptor Dikes
1. Interceptor Dikes are built across a
roadway to intercept runoff flowing down
the graded right of way. Runoff can be
directed into any safe disposal area such
as a vegetated area or completed storm
sewer. Because the soil dike slows down
runoff, sediment may be deposited on the uphill
side of the dike. This sediment must be checked
after every storm and removed before it impairs
the efficiency of the dike.
6-3
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2• Gravel Interceptor Dikes
are used when the weight of construction
traffic would be too much for a wet soil
interceptor dike to withstand. It is sim-
ilar to a soil dike, except that it is
made from gravel or crushed rock. A gravel
dike is less likely to be damaged or
washed out during a heavy storm. It must
be checked and properly maintained.
C. Diversion Dikes collect runoff and channel it
safely away from an erodible soil surface to
a safe disposal area. It is made of compacted
soil and is commonly used along the top of a
slope.
When the channel along the diversion dike is
steep, soil reinforcement measures such as
netting, mulching, and chemical stabilizers
are helpful. The diversion dike also requires
maintenance. It should be inspected after
each storm, and any damage repaired.
D- Diversions are often used on hillsides
6-4
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The soil excavated fron the channel of the diversion is
used to build a dike down hill from the channel. This
cornbination of channel and dike will create a larger flow
capacity.
A standard diversion dike with side slopes of two to one
and a two-foot wide top and 1.5 feet high will have good
flow capacity for drainage areas less than 5 acres.
A "top of cut" diversion is widely used in building
highways.
CAUTION: If a diversion structure is used, be careful when
working on a steep slope - a SLIDE could occur. The major
cause of sliding is the saturation of the soil by water
concentrated behind and within the diversion.
V. DISPOSAL OF DIVERTED FLOW
A. Onto Vegetation
The best way to dispose of diverted runoff is directly
onto a well vegetated ground surface. When the
amount of concentrated runoff is not too great,
the vegetation will filter the runoff, and the soil will
absorb sane of the water. Grass is the best vegetative filter.
6-5
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B. The Level Spreader
A level spreader is often required when the amount
of runoff is too great to be disposed of direct-
ly onto a vegetated area. The level spreader
changes a concentrated flow into non-erosive
sheet flow.
C. Downdrain Structures are used to carry runoff
from one level to another.
1. Flexible Downdrains
A flexible downdrain consists of a metal
inlet or end section (the front lip is very
important. It anchors the device and pre-
vents the seepage of water b'eneath the drain.)
A metal extension collar, normally about
six feet long, and a collapsible drain
tube made of heavy duty fabric are the other
components of a flexible downdrain.
If the flexible downdrain is to perform
properly, the inlet section must be tilted
downward. The soil should be tightly com-
pacted around the inlet. This measure
is taken to prevent piping - the
flow of water along the outside rather than
the inside of the inlet, it is necessary also to
have adequate fill over the pipe entrance - at least
12 inches over the top of the pipe.
6-6
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2. Sectional Downdrains
A sectional downdrain is a half-round or
third round pipe made from bituminized fiber,
galvanized steel or other material. A formal
design is needed to determine what size
sectional downdrain you need to carry your
flow without water spilling out of the pipe.
When used as a temporary downdrain, the pipe can
be placed directly on the finished ground and
secured in place with wooden stakes. Where two
pieces of sectional downdrain are joined
together, the uphill section overlaps the down-
hill by about three inches. The sectional
downdrain can also experience piping.
3. Flumes
A flume is a flat bottomed ditch lined
with either concrete or asphalt. A formal
design is required to properly size a flume
for the expected water flow. Piping can be a
problem unless a good bond is maintained be-
tween the diversion structure and the flume
inlet.
4. Energy Dissipators
Energy dissipators are used to slow down the
6-7
-------
flow of water at the drain outlet to lessen
the chance of erosion. On temporary con-
crete flumes, stones or concrete blocks are
sometimes set into the concrete so they
protrude up into the flume. This
slows the water. Placing a blanket of large
crushed stone or concrete at the outlet will
accomplish the same thing.
6-8
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STORMWATER RUNOFF
Review Questions - Fill in the bitnks
1. During construction, grading often causes
2. The runoff travels, the more soil it
disrupts and carries.
3. Soil deposited into our waterways where runoff concen-
trates is called .
4. is nature's greatest runoff reducer.
5. During a heavy rainfall, runoff will more than double when
just 20% of a area is made impervious
6-9
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CONTROL OF RUNOFF
Review Questions True or False
1. There are two ways to control runoff on an area
struction; decreasing the amount of runoff and use of a
diversion.
2. By staging, we mean getting all grading accom-
plished at one specific time during construction.
3. In using scarification as a form of surface
roughening, we simply loosen the soil to a
shallow depth without turning it over.
4. To be most effective, surface roughening must be
vertical or up and down a slope.
6-10
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DIVERSION STRUCTURES
Review Questions - Pick the best answer for the following
and fill-in the answer space with the
correct letter.
1. An example of a permanent diversion structure would be
a. a flexible downdrain
b. a top of cut ditch
c. a soil interceptor dike
d. a level spreader
ANSWER
2. To prevent excess buildup, sediment must be removed
from soil interceptor dikes
a. after every storm
b. after every other storm
c. at least once per month
d. daily
ANSWER
6-11
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TYPICAL DESIGN CRITERIA FOR A SOIL INTERCEPTOR DIKE
Graded
Right-of-Way
CROSS SECTION
2:1 or
Flatter
Slopes
Fl
Upslope Toe
Outlet onto Stabilized Area
ISOMETRIC VIEW
GENERAL NOTES:
a. Drawings not to scale
b. Top width may be widened, slopes may be flattened
c. Outlet should function with minimal erosion
6-12
-------
TYPICAL DESIGN CRITERIA FOR A GRAVEL INTERCEPTOR DIKE
Graded Right-of-Way
3:1 Slope or Flatter
CROSS SECTION
TOP ISOMETRIC VIEW
GENERAL NOTES
a. Drawing not to scale
b. Top width may be widened; Slopes may be flattened
c. Outlet should function with minimal erosion
6-13
-------
TYPICAL DESIGN CRITERIA FOR A DIVERSION DIKE
Cut or
Fill Slope
h _~
in.
2:1 Slope or Flatter
CROSS SECTION
Positive Grade
Upslope Toe
Cut or Fill
Slope
GENERAL NOTES:
a. Drawings not to scale.
b. Outlet to stabilized area,
6-14
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DIVERSION STRUCTURES
Review Questions - Fill in the blanks
1. Another name for the dike is
2. The main function of the gravel interceptor dike
is- not to filter but to runoff.
3. The diversion dike is usually a dike of
soil built along the top of a cut or fill.
4. One place where a diversion dike may not be com-
pacted is a area.
5. On hillsides, a is constructed by excavating
from the channel and constructing the dike on the downhill side.
6. In building any kind of diversion structure, you must
be careful to avoid the possibility of a ^__
on the lower lying slope.
6-15
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LEVEL SPREADER
Review Questions True or False
1 • The best way to dispose of diverted runoff
is directly onto a well vegetated area.
2. The level spreader is very similar to a diver-
sion ditch.
3. The length of the level spreader will vary
with the amount of water to be disposed of.
4. Being well stabilized with vegetation is help-
ful but not a must for a level spreader.
5. The most important feature of a level spreader
is its depth.
6-16
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TYPICAL DESIGN CRITERIA FOR THE LEVEL SPREADER
2:1 or Flatter
0.5' Min.
Jndisturbed Soil
Stabilized by
Existing Vegetation
SECTION A - A
ISOMETRIC VIEW
GENERAL NOTES:
Drawing not to scale
6-17
-------
FLEXIBLE DOWNDRAINS
Review Questions - Pick the best ans'wer for the following
and fill-in the answer space with the
correct letter.
1. The metal inlet of a flexible downdrain has a front lip,
Its function is to:
a. anchor the device
b. prevent the seepage of the water beneath the drain
c. filter sediment
d. both a and b
ANSWER
2. The flexible downdrain is subject to the piping effect,
This is:
a. too much flow ,
b. flow alongside the inlet
c. a tear in the tube
d. none of the above
ANSWER
6-18
-------
DOWNDRAIN STRUCTURES
Review Questions - Fill in the blanks
1. When used as a temporary downdrain structure, the
sectional downdrain is secured in place with
stakes.
2. To avoid , the soil must be tightly com-
pacted around the entrance to a sectional downdrain.
3. A is a flat bottomed ditch
lined with either concrete or asphalt.
4. Whatever your downdrain structure, severe
at the outlet is often a problem.
5. The role of the energy dissipator is to
down the flow of water before it flows onto the soil surface.
6. Probably the most frequent cause of failure of the flexible drain is
inadequate fill over the entrance end of the pipe - this should be
at least inches over the top of the pipe.
6-19
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FINAL REVIEW QUESTIONS
Answer the Following
1. R that is not a when it comes
in contact with the soil becomes s
r .
2. Three basic causes of runoff during construction
are:
a. G during construction that
destroys v .
b. Construction that changes the n
b of the land, turning
g slopes into s
slopes.
c. Construction that covers large portions of soil
surface with r and c or
a pavement.
3. Runoff can be controlled by:
a. D amount of runoff by using
s treatment p
b. D diverting runoff to a safe outlet.
6-20
-------
4. Three special grading practices used to con-
trol runoff are:
a. s
b. s r
c. preserving v b
5. True or False - A permanent diversion structure
can be defined as one that will serve both dur-
ing and after the construction period.
6. The two basic kinds of interceptor dikes are:
a.
b.
7 . A d d is a run-
off control structure formed with c
soil and usually built along the t of
a slope or around the perimeter of a
c site.
8. On natural hillsides where fill soil for a dike
is not available we often use a d
d .
9. The best way to dispose ot diverted runoff is
directly onto a w v
ground surface.
6-21
-------
10. A 1 s is a bench
cut into an undisturbed area which changes
concentrated flow into sheet flow.
11. Three downdrain structures used to carry
runoff from one level to another are:
a. f d
b. s d
c. f
12. is the flow of runoff
alongside rather than through a downdrain
structure.
13. When large amounts of runoff must be disposed
of at a downdrain outlet, we often use an
e d to slow down
the r as it flows onto the
ground surface.
6-22
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1
EROSION AND SEDIMENT CONTROL
VEGETATIVE SOIL STABILIZATION
WORKBOOK
-------
CONTENT
I. CRITICAL AREAS
II. VEGETATIVE STABILIZATION- MID ATLANTIC REGION EXAMPLES
A. Temporary
B. Permanent
III. PERMANENT PLANT MATERIALS
A. Grass
B. Legumes
C. Herbaceous Plants
D. Ground Cover
E. Vines
F. Shrubs
G. Trees
IV. SELECTING PROPER PLANT MATERIALS
A. Climatic Conditions
1. Temperature
2. Rainfall
3. Exposure
B. Soil Conditions
1. Fertility
2. Acidity
3. Droughty Soil
4. Wet Soil
C. Site Usage
D. Site Maintenance
7-1
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V. METHODS OF ESTABLISHING VEGETATION
A. Seeding
B. Sprigging
C. Sodding
VI. TIME OF PLANTING
A. Cool Season Plants
B. Warm Season Plants
VII. SOIL ADDITIVES
A. Fertilizer
B. Lime
VIII. MULCHING
IX. TOPSOILING
X. ESTABLISHING VEGETATION ON CRITICAL SOIL SURFACES
A. Soil Preparation
1. Adding Lime and Fertilizer
2. Tilling
B. Seeding
C. Mulching
D. Sodding
XI. MAINTENANCE OF CRITICAL AREAS
A. Follow-up
B. Periodic
XII. REVIEW QUIZ
7-2
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I. CRITICAL VS. NONCRITICAL AREAS
A. Critical area - a sediment producing or highly
erodable area. It may be an area where grading
operations have stripped away the fertile top-
soil to expose subsoil or an area bare of vege-
tation due to too much foot traffic.
II. VEGETATIVE STABILIZATION
A. Temporary vegetative stabilization is the use of
certain fast growing, robust plant materials to
stabilize a site for a temporary period of time
(less than one year). Both annual and perennial
plants are used.
1. Temporary stabilization becomes necessary
when grading leaves an area exposed for a
prolonged period of time.
2. The type of temporary vegetation used will
depend on
a. time of year
b. site location
c. soil type and condition
7-3
-------
B. Permanent vegetative stabilization is performed
when it is necessary to stabilize an area for
more than one year. Perennial plants must be
used ; temporary annuals may be used in mixtures
with permanent plants.
1. The life of this type of cover will depend
on
a. type of vegetation
b. maintenance
c. type of use received
7-4
-------
III. PERMANENT AND SEMIPERMANENT PLANT MATERIALS
A. Grasses
1. Grasses are the most widely used plant
material for stabilizing critical areas.
2. Grasses commonly used for critical
stabilization in Maryland include:
a. Kentucky 31 tall fescue
b. Creeping Red fescue
c. Tufcote Bermudagrass
d. Red Top
e. Weeping Lovegrass
B. Legumes
1. Legumes are also very popular for stabiliz-
ing critical areas.
2. They are long-lived and some require less main-
tenance than grasses.
3. Commonly used legumes include:
a. Crownvetch
b. Sericia lespedeza
c. Korean lespedeza
d. Sweet clover
e. Birdsfoot trefoil
7-5
-------
C. Herbaceous Plants
1. They play an important role when an area is
to be returned to natural cover.
2. In residential areas they may be considered
weeds.
3. Along major highways these materials play
an important role in protecting soil from
erosion.
7-6
-------
D. Ground Covers
1. Because of their high cost as compared to
grasses and legumes, these materials are
not extensively used for critical area
stabilization. However, on terrain with
very severe problems, where less durable
grasses and legumes are not able to perform
properly, these plant materials are of great value,
2. "Ground covers" refers not to grasses or
legumes specifically, but to such plant
types as vines and low growing plants. Crown-
vetch is a legume which is considered a very
good ground cover plant in some areas.
E. Vines
1. some do well on poor soil and steep slopes.
2. are used for area beautification as well
as soil stabilization.
3. examples are:
(a) Kudzu
(b) Honeysuckle
F. Shrubs
1. are used for area beautification as well as
soil stabilization.
2. are used to reduce maintenance costs.
3. may serve as screens and barriers.
7-7
-------
G. Trees are planted for erosion control, area
beautification, shade, privacy, and seund abatement,
IV. SELECTING PROPER PLANT MATERIALS
A. Climatic Conditions
1. Temperature
2. Rainfall
3. Exposure
a. wind
b. sunlight - an important consideration
4. The first two conditions, and to a certain
extent exposure, are related to the geo-
graphic area in which the site is located.
5. The most critical exposure problems are found
in wooded areas where tall trees provide ad-
ditional shade.
B. Soil Conditions
1. Fertility - subsoils are usually low in fer-
tility and may be acid - fertility refers to
the supply of plant nutrients in the soil.
2. Acidity - acid soils are those having pH
values of less than 7. A value of 7 is
neutral. A value above 7 is basic or
alkaline.
7-8
-------
(a) Plant nutrients are furnished by
adding fertilizers and the acid-
ity is usually reduced or con-
trolled by adding lime.
(b) Maintenance can be minimized by
selecting plant materials that are
adaptable, as nearly as possible,
to the natural condition of the
soil.
(c) Some plant materials do better in
poor soils than others. Likewise,
some plants prefer or tolerate an
acid soil, while others require a
basic or alkaline soil.
(d) On low fertility soil, plant mater-
ials like grasses can be made more
effective by mixing with a legume,
like clover,.which can furnish ni-
trogen, an important plant nutrient.
3. Droughty Soil
(a) Unable to retain an adequate supply
of water
(b) To prevent this problem the soil
should contain at least 25 to 30% silt
and clay size particles (fines).
7-9
-------
(c) The problem can be taken care of in
three ways:
(1) by selecting drought-resistant
plant material.
(2) by top-dressing with 4 to 6
inches of non-droughty subsoil
or good topsoil.
(3) by soil conditioning - mixing
silt and clay soil or organic
material into the upper 3-4
inches of droughty soil.
Wet Soil
a. Soils that stay saturated for pro-
longed periods of time.
b. Seepage areas become difficult to sta-
bilize with vegetation and can cause
considerable erosion.
c. The problem of wet soil can be handled
by
(1) using plant materials tolerant
of wet soil.
(2) installing gravel and pipe under-
drains.
7-10
-------
C, Site Usage refers to the type of usage plant
materials receive at a site. Must be consid-
ered when selecting plant materials.
D. Site Maintenance will also influence the type
of plant materials being used. Some sites are
easy to maintain, while others are nearly im-
possible because of physical barriers.
V. METHODS OF ESTABLISHING VEGETATION
A. Seeding
1. Most grasses and legumes are established
by seeding.
2. The quantity of seed required to vegetate
an area will depend upon what type or types
of plant materials are being used.
3. Check application rate in "The Standards and
Specifications for Soil Erosion and Sedi-
ment Control".
4. Use a small test plot to observe performance
prior to planting any large areas.
5. Common bermudagrass can be established satisfac-
torily by seeding. Other bermudagrasses may only
only be established by sprigging.
B. Sprigging
1. This involves the planting of sprigs of live
vegetation rather than seed.
2. Many ground covers and vines are established
by sprigging.
7-11
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C. Sodding
1. This method uses live vegetation to quickly
stabilize a site.
2. Completely covers the surface.
3. Often the most desirable and effective means
of quickly stabilizing highly critical
areas such as waterways.
VI. TIME OF PLANTING
The success of a vegetative stabilization program will
depend to a large degree on the weather occuring dur-
ing the critical period immediately following plant-
ing. This is especially true for seeding.
A. Cool Season Plants
1. require cool, moist conditions to germinate
2. best planted during early fall and early spring,
B. Warm Season Plants
1. best planted during late spring or summer
2. some moisture essential
VII. SOIL ADDITIVES
Critical area planting requires the addition of fer-
tilizers and may need lime to the soil. The amount
of these additives needed will depend upon the type of
plant materials used and the condition of the soil.
7-12
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Soil testing should be performed to determine the
additive requirements.
When testing cannot be performed, use the standard
application rates, found in the Standards and Spec-
ification for Erosion and Sediment Control.
A. Fertilizer
1. contains important plant nutrients
a. Nitrogen (N)
b. Phosphorus (P)
c. Potash (K)
2. "10-10-10" is a "well balanced" fertilizer and is
the percentage ot "N-P-K" in the fertilizer.
3. Quick release fertilizer acts quickly.
4. Slow release fertilizer acts at a controlled
rate.
B. Lime
1. Neutralizes acid soil conditions
2. Crushed dolomitic limestone may be used rather
than regular limestone.
3. Avoid using too mucn lime around plants that
require acid soil.
7-13
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VIII. MULCHING
A. very essential after preparation of a seedbed,
as well as for the establishment of ground
covers, vines, shrubs, and trees.
B. involves the placing of material on the soil to
protect it from erosion and to provide a proper
environment for the growth of vegetation.
C. shields the soil from the impact of rainfall and
from the scouring effect of runoff.
D. insulates the soil from intense heat and cold.
E. conserves moisture.
F. Mulch Materials
1. straw - most commonly used
,<•
2. wood chips
3. wood fiber (poor)
4. chemical emulsions
5. fiberglass products
G. Application Rates
1. straw - 1 to 2 tons per acre
2. wood fiber mulch - 1000 to 1500 Ibs. per acre
3. wood chips - 40 to 60 cubic yards per acre
a. The heavier application rates should be
used on steep slopes and along waterways
where the potential for soil erosion is
7-14
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greatest. Lighter application rate applies
to relatively tlat areas that do not carry
concentrated runoff.
IX. TOPSOILING
A. Involves the placing of 4 to 6 inches of good
quality topsoil on the final graded subsoil
surface prior to preparing a seedbed.
B. Usually topsoil is acquired by salvaging and
stockpiling the surface material at the begin-
ning of grading operations.
C. Tests should be performed to insure that the
topsoil is of adequate quality.
D, Topsoiling Slippage becomes a possibility when
topsoiling steep slopes. There are three fac-
tors that combine to cause this problem.
1. High moisture content. Because it contains
organic material, a topsoil is able to ab-
sorb and retain a large amount of water.
By absorbing the water, the weight of the
topsoil increases, and at the same time it
becomes more fluid.
7-15
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2. Slope steepness. The steeper a slope, the
easier it is for a heavy, wet topsoil to
slip down the slope.
3. Poor Bond. Lack of a good bond between the
topsoil and the underlying subsoil. The un-
derlying soil should be roughened to a depth
of 2 - 3 inches prior to spreading the
topsoil. After it is spread, the topsoil
should be firmed.
X. ESTABLISHING VEGETATION ON CRITICAL SOIL SURFACES
A. Soil Preparation
1. The first step in the preparation of a seed-
bed involves the placing of lime and fertil-
izer on the soil.
2. Tilling to a depth of at least 3 inches with
a disc.
a. mixes the lime} and fertilizer into the
soil.
b. allows more air and moisture to penetrate
the root zone.
c. breaks up clods of soil.
d. should tie performed along the con-
tour of the ground surface, if feasible.
7-16
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B. Seeding
1, Seeding is usually done after the lime and
fertilizer have been worked into the soil.
2. Rolling or cultipacking should follow the appli-
cation of seed - where conditions permit.
3. Inaccessible areas can be limed, fertilized
and seeded with a hydroseeder.
*~ • Mulching is done immediately after the seeding
operation. There are several methods for apply-
ing and securing mulch.
1. Mulch Blower is a labor saving device used
when mulching large seedbeds.
2. Emulsified Asphalt is sprayed on straw mulch
to prevent it from being blown or washed
away. Upon curing the asphalt binds the in-
dividual straw fibers together to form a mat
that is more resistant to erosion. It is
often undesirable in residential areas be-
cause of its sticky nature.
3. Chemical Binders are used to avoid the sticky
problem of asphalt. These chemicals are
mixed with water and sprayed on the straw.
Upon curing, the chemical binds the straw
fibers together.
7-17
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4. Peg and String method is used in small
areas where spraying cannot be performed.
Wooden stakes or metal pins are driven
into the ground and a strong twine is
strung in a criss-cross manner between
them.
5. Netting is used to secure straw mulch
where heavy flow is expected. Either a
plastic, fiberglass, or jute netting is
used. The netting is firmly secured to
the ground with metal pins. Jute netting
also acts as a mulch.
6. Mulch anchoring tool is often used to anchor
straw on accessible areas. It consists
of a gang of notched coulters, resembling
a disc used for tilling except they are blunt.
When pulled over the mulch, the revolving discs
punch some of the straw into the soil.
7. Hydroseeder is used to apply seed, fertilizer,
lime and wood fiber to inaccessible areas. The
materials are mixed with water to form a slurry
and are then sprayed onto the seeded area.
7-18
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8. Excelsior Blanket is made up of coarse
wood fibers reinforced oy netting. Mattings
of this type are used on drainageways and
otner critical areas exposed to a concentrated
flow of water during storms. A slow-release
nitrogen should be used with excelsior
blanket.
9. Glassroot consists of long strands of
fiberglass which are sprayed onto the
ground surface with a special apparatus
powered by compressed air. This mater-
ial is used on highly critical areas
where long-lasting mulch protection is desired.
D. Sodding
1. The soil must be conditioned by applying needed
lime and fertilizer and disking it into the top
4" of soil.
2. Large stones or debris must be removed from the
surface
3. The surface is graded to remove irregularities.
4. Strips of sod must be tightly butted together on
the contour with staagered joints.
5. After placing, the sod is watered and then rolled.
XI. MAINTENANCE OF CRITICAL AREAS
A. Follow-up
1. Required when seeding, sodding, or other
vegetative practices do not achieve the
desired degree of stabilization.
7-19
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2. Materials planted in the spring should be
inspected during the summer or early fall
so that corrective action can be taken
during the fall planting season.
3. Areas stabilized in the fall should be
inspected early in the spring so that
maintenance can be performed during the
spring planting season.
4. If the cover did not develop properly, the
area should be seeded and fertilized with
half the rates originally applied.
5. If stand is over 60% damaged, complete
seedbed preparation and seeding must be per-
formed - before doing this, check plant ma-
terial and soil condition.
B. Periodic Maintenance
1. Performed after the vegetation has been
established.
2. Periodically inspect plant cover to see if
a top dressing of fertilizer or lime is
required.
3. Spray if insect damage is severe.
4. Spot seed areas damaged by traffic or by
other means.
5. Mowing is a periodic maintenance practice.
7-20
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QUESTIONS 1
Fill in the blanks
1. A area is a sediment-producing or
highly e area.
2. Utility easements, waterways, and building sites
are common areas.
3. stabilization uses certain
fast growing plant materials to stabilize a site
for than one year.
4. stabilization uses per-
ennial plants.
5. The type of temporary vegetation to be used on a
site will depend upon:
a. t of y_
b. site 1
c . s type and c
7-21
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QUESTIONS 2
Multiple Choice - circle
the correct answer
1. Which of the following is not a permanent plant?
a. grass (Perennial) d. mulch
b. shrub e. legume (Perennial)
c. tree f. Crownvetch
answer (s)
2. Grasses commonly used for critical area stabiliza-
tion include:
a. Crownvetch
b. Weeping lovegrass
c. Kentucky 31 tall fescue
d. both a. and c.
e. both b. and c.
f. all of the above
answer (s)
3. The chief reason for the durability of legumes is:
a. they are able to add phosphorus to the soil
b. they are able to withstand freezing temperatures
c. they are able to remove nitrogen from the air,
utilize it, and add it to the soil
d. they are able to remove nitrogen from the soil
and release it into the air
answer (s)
(Go on to next page)
7-22
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4. During the winter, the foliage of legumes
a. stays green
b. grows back (Applies to certain areas
c. dies of U.S. only)
d. does none of the above
answer (s)
5. Where mowing must be performed, the preferred plant
material to use is
a. legume
b. grass
c. shrubs
d. herbaceous plants
answer (s)
6. In residential areas, what material may be con-
sidered weeds?
a. mulch
b. shrubs
c. turf grass
d. trees
e. herbaceous plants
answer (s)
7-23
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True or False
_1. The term "ground covers" refers to grasses
and legumes specifically.
_2. Trees, vines, and shrubs are not used ex-
tensively to reduce maintenance costs.
_3, The primary reason for planting trees is
noise abatement.
_4. Periwinkle is a ground cover.
7-24
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QUESTIONS 4
Fill in the blanks
1. Climatic conditions include
and
2. Wind and sunlight are two types of
3. exposure is a very important con-
sideration.
4. The most critical exposure problems are found in
areas, due to shading.
5. Subsoils are generally low in and may be
6. A pH value of 7 is
True or False
7. We would usually plant a tall legume or shrub
in the channel of a waterway.
_8. Legumes are more suitable than grasses in areas
receiving a great deal of foot traffic.
_9. Not all plant materials require the same degree
of maintenance.
7-25
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Multiple Choice
Some grasses and legumes may be established by
a. sodding
b. sprigging
c. seeding
d. all of the above
answer (s)
Bermudagrass is usually established by
a. sodding
b. sprigging
c. fertilizing
d. seeding
answer (s)
English ivy is usually established by
a. sodding
b. sprigging
c. seeding
d. fertilizing
answer (s)
The most desirable and effective means of quickly
stabilizing certain highly critical areas, such as
waterways is
a. seeding
b. sodding
c. sprigging
d. none of the above
answer (s)
7-26
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QUESTIONS 6
Fill in the blanks
The success of a vegetative stabilization program
will depend to a large degree on the
occuring during the critical period immediately
following planting.
2. Critical area planting involves the addition of
and possioly lime to the soil.
3. Fertilizer contains nitrogen, p_ and
p , N-P-K.
The addition of dolomitic limestone thi
of acid soils.
5. Dolomitic Limestone adds calcium and m ^_^_
the soil and helps correct soil conditio
7^27
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Multiple Choice
1. is the most commonly used mulch
material.
a. wood chips c. chemical emulsions
b. wood fiber d. straw
2. Which of the following is a characteristic of
mulch?
a. protects the soil c. conserves moisture
b. insulates the soil d. all of the above
answer (s)
3. is usually acquired by salvaging
and stockpiling the native material at the begin-
ning of grading operations.
a. mulch c. topsoil
b. lime d. sod
4. Which of the following is not a contributing
factor to soil slippage?
a. high moisture content
b. poor shear strencrth
c. slope steepness
d. high acid content
answer (s)
7-28
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True or False
_1. The first step in the preparation of a seed-
bed is sodding.
2. Cyclone spreaders can be used to apply fer-
tilizers .
3. Palletized fertilizer can be applied with a
truck mounted spreader bar.
4. After applying (lime and)fertilizer, the
area is tilled to a depth of at least twelve
inches.
5. Tilling should be performed along the contour
of the ground surface, if feasible
_6. On steep slopes where rolling cannot be per-
formed, a cleated dozer is often used to
produce the desired surface texture by moving
up and down the slope.
7-29
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Fill in the blanks
1. Immediately after seeding operations are completed,
the area should be .
2. In residential areas receiving heavy foot traffic
a t is often undesira-
ble because of its sticky nature.
3. E b is a mulch mater-
ial that is sometimes used in the revegetation of wat-
erways.
4. On accessible areas, a m
t is often used to anchor straw mulch.
5. W mulch is applied with
a hydroseeder.
6. Before placing sod, the soil must be c
7-30
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QUESTIONS 1O
True or False
1. Follow-up maintenance is required when seed-
ing, sodding, or other vegetative practices do
not achieve the desired degree of stabilization,
2. Areas stabilized in the fall should be in-
spected early in the spring.
3. When inspection reveals that the cover did
not develop completely the area should be
seeded and fertilized with the same amounts
originally applied.
4. Spot seeding is required when inspection re-
veals that sixty percent of the cover is
damaged.
5. Mowing is another follow-up maintenance
practice.
7-31
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QUESTIONS 11
1. A critical area is any 2 surtace that is
s producing or severely e .
2. Some common critical areas are u
e , w and b
Temporary vegetative stabilization is used to sta-
bilize a site for a time period of than
one year. By reseeding an annual may be effective for
several years.
The type of temporary vegetation will depend on:
a. of year that seeding is done
b. site
c. soil and
5. Permanent vegetative stabilization is performed
when an area has to be stabilized for
than one year.
6. The most widely used plant materials for stabili-
zation are
7. Two grasses commonly used for stabilizing criti-
cal areas in Maryland include k and
w or creeping red fescue,Eufcote
bermudagrass or red top.
8. are also very popular for sta-
bilizing critical areas with low fertility soils,
9. The chief reason for the durability of the legume
is that it is able to remove from
the air and utilize it.
7-32
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10. c is a close-growing, legume that may
be established on subsoils.
11. When an area is returned to a natural cover of
vegetation play an
important role.
12. in any plants out of place
may be considered .
13. Canada thistle is a n herbaceous
plant that must be controlled, while the black-
eyed Susan is a non- one.
14. Deciduous plants are those on which the f_
dies in the
15. In residential areas vines, shrubs and trees are
used for a b as well as
n a
16. Lily turf, English ivy, and periwinkle are exam-
ples of .
17. Three reasons for planting trees are:
(1) b
(2) p_
(3) n
18. The four factors governing the proper selection of
plant materials are:
(1) C c
(2) S
(3) S u
(4) S m
19. conditions include temperature,
rainfall and exposure.
7-33
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20. The two types of exposure are and
21. The most critical exposure problems are found in
w areas, if heavily shaded.
22. Subsoils are generally low in f and
are frequently .
23. A pH value of more than 7 is
24. The acidity of the soil is neutralized by adding
25. On low fertility soil we can benefit plant materials
like grasses by mixing in a 1 .
26. Droughty soil is not able to retain an adequate
supply of w for p use.
27. What are two ways the problem of droughty soil can
be taken care of?
a. Select a plant m that is drought
r .
b. T the droughty soil with
to inches of
non-droughty subsoil or good topsoil.
28. In seepage areas where vegetation is difficult to
maintain, it may be necessary to cover the seepage
area with a protective cover of c
s . Better yet, drain it.
29. Three methods used to establish ground covers,
grasses and legumes on critical areas are:
(1) (2) (3)
Notall plants are suitable for each method.
30. Almost all grasses and legumes are established by
7-34
-------
31. involves the planting of sprigs of
live vegetation rather than . .
32. is often the most desirable and
effective means of Q stabilizing
highly critical areas.
33. Plant materials may be categorized as either
season plants or
season plants.
34. Critical area planting requires the addition of
and possibly to the soil.
35. Fertilizers contain three important plant nutri-
ents :
(1) (2) (3)
36. Lime performs several very important functions.
Its most important function is in correcting
a s conditions.
37. Three ways that mulching helps the establishment of
vegetation are:
a. P the soil from the impact of
r and from the scouring effect
of r
b. I the soil from intense
and .
c. Conserves m
38. Name three types of mulch materials:
(1) (2) (3)
39. T is usually acquired by salvaging
and stockpiling the surface material at the begin-
ning of grading operations.
7-35
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40. Two of the three causes of soil slippage are:
(1) (2)
41. Soil preparation involves wording 1_
and f into the soil.
42. Straw mulch must be to keep it from
blowing away.
43. Three materials for securing straw mulch are:
(1) E a
(2) N
(3) C b tor peg & string)
44. Before placing sod, the soil must be c .
45. There are two types of maintenance;
and
46. maintenance is performed after the
vegetation has been successfully established.
47. maintenance is required when seed-
ing, sodding, or other vegetative practices do not
achieve the desired coverage.
48. Mowing is a maintenance practice.
7-36
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EROSION AND SEDIMENT CONTROL
STREAM EROSION CONTROL
WORKBOOK
-------
CONTENT
I INTRODUCTION TO STREAM EROSION CONTROL
A. Channel Protection
B. Stormwater Runoff Management
II CAUSES OF EROSION
A. Hydraulic Force
B. Solution
C. Corrasion
III FACTORS AFFECTING THE AMOUNT AND RATE OF EROSION
A. Amount of Turbulence
B. Meandering of Stream
C. Obstructions
D. Velocity
E. Streambed and Streambank Materials
F. Soil Makeup and Texture
G. Gradient of Channel
H. Vegetation
I. Man's Activities
IV USE OF VEGETATION IN STABILIZING STREAMS
A. Advantages- Effective and Economical
B. Choosing Plant Materials
C. Procedures for Establishing Vegetation
D. Necessity of Secondary Reinforcements
8-1
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V STRUCTURAL STABILIZATION
A. Necessity of Structural Stabilization
B. Critical Areas
C. Revetments
D. Grade-Control Structures
VI STORMWATER MANAGEMENT
A. Effects
1. Reduces Runoff
2. Controls Release of Runoff
B. Methods
C. Storage on Recreation Areas
D. Detention Basins
E. Holding Tanks
F. Infiltration Systems
G. Stream Channel Control and Floodplain Storage
VII MAINTENANCE - ESSENTIAL IN GOOD STREAM EROSION CONTROL
8-2
-------
I INTRODUCTION TO STREAM EROSION CONTROL
A. There are two basic ways to control waterway erosion.
The first is by protecting the channel against
erosion. The second is by managing the water that runs
off after a storm, so that it is less likely to cause
erosion.
B. Most of the damage done to streams and other
waterways occurs during heavy rains, or jus.t
after them, when the water is flowing at its
maximum or "peak."
1- Proper control of this stormwater, before it
enters the streams, and while it flows along
them, will do a great deal to solve this problem.
2. Proper vegetative practices and good structures
built to control erosion, will help as well.
II CAUSES OF STREAM EROSION
A. Water exerts a force against the soil, as it flows
along. The force of flowing water is called
"hydraulic" force. Hydraulic force is responsible
for a major portion of waterway erosion.
B. Another way in which water can erode is by solution.
Water can slowly dissolve rock materials. The sol-
ution of limestone to form caves or sinkholes is a
good example of this form of degradation.
8-3
-------
C. A third way in which water can remove material
from a waterway is through corrasion. Corrasion
occurs, when materials such as bits of soil or rock
being carried by the water strike the bottom or
sides of the waterway, and dislodge or displace
other materials.
Ill FACTORS EFFECTING THE AMOUNT AND RATE OF EROSION
A. The amount and rate of erosion you can expect in a
given stream depends on several factors. One of
these factors is the turbulence of the flow of
water. In any channel, smoothly flowing water
causes less erosion than turbulent water.
B. Another factor that effects the rate of erosion
is the meandering of the stream, that is, how much
it deviates from a straight course. Where the
stream bends, the water erodes the outside of the
channel more than it does the straight stretches,
because the force of the water is directed at the
outside bank at this point.
C. Obstructions also have an effect. Obstructions in
the channel, such as brush or boulders, may deflect
the flow toward the bank, and cause additional ero-
sion.
D. During periods of high water the velocity usually
increases, thereby accelerating the rate of erosion.
Not only does the water flow faster, during periods
of high water flow, the turbulence increases. The
8-4
-------
flowing water, with its increased turbulence and
velocity, scours the bed and erodes the banks of
the stream.
E. The amount and rate of erosion also varies depend-
ing on the materials in the bed and bank. Many bank
materials are likely to slide or slough off into the
channel when the base of the bank is saturated or
when the stream has undercut the bank.
F. The texture or makeup of the soils in the channel
and banks will have an important effect on the rate
the stream erodes.
1. Those soils in which the particles are strongly
bound together will erode less easily than soils
made up of loose grains. Larger materials, such
as gravel, cobbles, and boulders will erode very
slowly.
2. Sand, silt, and clay particles will erode much
more rapidly, because they are lighter and more
easily carried away.
3. Water flowing over soils which contain a mix-
ture of materials, including gravel or larger
stones, will sort the particles by size until
the bottom is covered or "armored" with only
the larger materials.
G. Another factor that effects the rate of erosion
is the slope or "gradient" of the channel.
1. The gradient is the change in elevation of a
stream, over a certain horizontal distance.
8-5
-------
2. Gradients are measured in feet of vertical
change per mile of horizontal distance, feet
per hundred feet, expressed as percent, or feet
per foot.
3. The steeper the gradient, the more rapid the
erosion of the streambed, other factors being
equal.
H. Another factor that effects erosion is the presence
and condition of vegetation in the channel and on
the banks of the stream. The roots of trees,
shrubs, vines, grasses, and other plants help hold
the soil in place.
I. Wherever man's activities have altered the natural
watershed there are a number of new factors that
will have an effect on the rate and amount of run-
off and resultant erosion.
1. These factors include the removal of natural
vegetation, the compaction of the soil, any
change in the topography, and the use of imper-
vious coverings :such as pavements or roofs.
2. Increased erosion may also be caused by alter-
ing the natural channel of a stream. This
process is called "channel realignment."
a. It is often performed to make more room for
development. Although channel realignment
may make more land available for develop-
ment, it also has some drawbacks.
1. Since the change in elevation remains
the same, and the distance the stream
6-6
-------
travels is less, the gradient becomes
steeper. As a result, the water in the
new channel flows faster. The increased
velocity will increase the erosion.
2. Channel realignment also exposes bare
soil along the banks to the severe ero-
sive action of concentrated flow.
3. Before developing any watershed, you should
carefully study the natural streams to make
sure they can handle the higher rate of flow,
without causing increased erosion or flooding
IV USE OF VEGETATION IN STABILIZING STREAMS
A. Along natural streams, an effective and econom-
ical way to help reduce erosion from
surface runoff, is to preserve a buffer strip of
natural vegetation.
1. In intermittent streams, you can often stabilize
the waterway by planting a cover of grass over
the entire channel.
2. Even when the bed of a channel cannot be vegeta-
ted, you can usually stabilize the banks and
floodplain with vegetation.
B. Before choosing a plant material, you must consider
several factors. These include the erosive forces,
the soil and soil moisture, the exposure to sun-
light, and the steepness of the slope to be planted.
8-7
-------
1. To find out what type of vegetation is most
suitable for a given site, consult the Standards
and Specifications, or the local soil and water
conservation district, or a university extension
service.
C. Once you have selected suitable plant materials,
there are certain procedures you should follow to
establish the vegetation.
1. Along ditches, swales, and other intermittant
streams, you should usually plant vegetation
in strips. Plant moisture-tolerant vegetation,
that resists erosion extremely well, in the
critical area near the water line, and in the
bottom of the channel.
2. Plant conventional, robust grasses and legumes
above the critical zone.
3. For added protection, in critical locations
where the soil is very wet, you can plant bushes
and trees such as alder and willow, along the
banks.
4. Before planting a channel, check the slope of
the bank.
a. It is usually not recommended to grade
banks to greater than 50% or 2:1, if they
are to be stabilized vegetatively.
b. If the area to be planted is steeper than
8-8
-------
50% (2:1), the banks should be graded back.
will greatly facilitate necessary maintenance
later.
c. Vegetated waterways should be constructed
with gently graded sides that slope smoothly
into a wide bottom.
d. With this type of construction, it is easy
to vegetate the channel, the waterway blends
into the surrounding area, and you can mow
and maintain the grass without any unusual
problems.
e. Not only are grass waterways pleasant to
look at, they slow the flow of runoff and
allow the water to infiltrate more easily
into the soil.
5. Usually, you would seed streambeds in streams
which carry water only during and immediately
after runoff from a rainfall. These channels
generally should not be seeded, if the flow of
water exceeds four feet per second.
6. Where the waterways are designed to handle a
flow of water greater than four feet per second,
but less than seven, you should apply sod instead
of seeding.
a. Seasonal requirements also make it necessary
to apply sod.
b. However, if the soils erode at these veloci-
8-9
-------
ties, you will have to take certain structural
measures to prevent erosion, as well as using
seeding or sodding.
V SECONDARY REINFORCEMENTS
A. Whether you establish vegetation by seeding, sodding,
or sprigging, it will take some time before the
vegetation will provide its best protection. Until
that time, you will have to provide some secondary
reinforcement, such as mulches, nettings, or blankets.
1. Some of these materials are intended to provide
maximum protection at the time of planting and
degrade as the vegetative cover matures.
These materials include straw and other
organic mulches, jute netting, and excelsior
blanket.
2. When you need a reinforcement that lasts longer,
you can use more permanent materials. Examples
include fiberglass mulches, plastic netting, or
any of several types of mattings.
3. When the flow of water is expected to be severe,
you will have to secure the mulch with nettings.
These include fiberglass and plastic nettings.
A common problem in the use of netting in
waterways is the movement of water beneath the
protective material, and the
subsequent loss of soil by erosion. Permeable,
8-10
-------
granular soils are particularly susceptible.
To prevent this, establish erosion
checks across the waterway and beneath the netting
at intervals along the channel.
VI STRUCTURAL STABILIZATION
A. In certain places in streams, vegetative practices
alone are not enough to prevent erosion; you will have
to use structural devices to protect the stream from
scour or erosion.
B. Critical area along streambeds which may need struc-
tural stabilization include: the outside of bends
where the flow impinges or impacts against the stream-
bank, restrictions in the channel, junctions
where tributaries enter the main channel, and
places where the channel gradient is excessive.
C. Revetments are useful in areas where you need
to protect the streambanks.
1. The most popular material used in constructing
revetments is stone riprap. Stone riprap is
durable, heavy, and flexible.
a. By "flexible," we mean that the stone rip-
rap adjusts to changes in foundations that
result fromerosion beneath the stone, and
adjusts to scouring along the lower edge,
or "toe."
8-11
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b. In addition, the rough surface dissipates
some of the energy present in the flowing
water.
2. Other popular materials used in constructing
revetments are gabions and revet mattresses.
a. Gabions are wire baskets filled with stone.
Like riprap, they are usually used in areas
requiring heavy duty materials.
1. They are cubic, generally 3 feet by 3
feet by 3 feet.
2. Gabions are often used to hold very
steep slopes, and construct check dams.
b. Revet mattresses are similar in principle;
however, they are not as thick. They vary
in thickness from 6 to 12 inches, and usu-
ally cover an area 3 feet by 9 feet.
1. The advantage of this type of structure
over loose riprap or gabions is that you
can use a thinner layer of stone; you
can also use smaller stone. And, they
are more flexible than gabions or con-
crete.
2. Revet mattresses provide protection for
slopes, under bridges, and along streams.
3. Once the revet mattress is installed,
you can spread lime, fertilizer, and seed
over the revet mattress. Within a
8-12
-------
short time, if conditions permit, plants
will grow through the mattress, anchoring
it to the soil underneath, as well as
making the area more visually pleasing.
3. MONOslabs or checkerblocks or "grass pavers" are
also useful in stablizing critical areas. MONO-
slabs and checkerblocks are concrete grids, approx-
imately 2 feet by 1 1/3 feet by 4 1/2 inches. Each
grid contains several open spaces.
a. Laid side by side, they can be used to pave
parking areas as well as to stabilize
streambeds and atreambanks with slopes up
to 2:1. MONOslabs are relatively flexible,
because the individual blocks are not
rigidly attached to each other.
b. The open spaces in the grids can be filled
with soil and seeded. This provides an
attractive appearance.
c. In addition to stabilizing vulnerable
areas, riprap, revet mattresses, gabions,
and MONOslabs or, checkerblocks also allow more
runoff to infiltrate into the soil than most
other types of pavings or bank revetments would,
this reduces the runoff which would other-
wise increase the flow in the stream.
4. Fabriform is another good armor material to
use in constructing revetments, as well as other
structures for protecting the channel.
8-13
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a. Fabriform consists of a double layer of
heavy nylon fabric; a slurry of sand-cement
is pumped into the nylon fabric and allowed
to harden.
b. The finished product takes on a rough,
tufted look. At each depression in the
fabric surface there is a filter point.
This filter allows the water underneath
the Fabriform revetment to escape, while
retaining soil particles in place.
5. Other popular materials used to stabilize water-
ways are concrete, concrete block, and
sandbags filled with a sand-cement mixture.
6. For all revetments, to prevent seepage from be-
neath the revetment from undermining it, place
a filter between the soil and the revetment.
Use a cloth filter or a properly designed sand-
gravel filter for this purpose.
D. In certain areas, you will need to provide extra
protection for the streambed, as well as for the
streambank. To prevent erosion of the streambed,
use a grade-control structure. Grade-control
structures physically prevent the streambeds from
being eroded, and reduce the gradient, thus slowing
the flow of water.
1. A grade-control structure consists of some
durable material placed across the bottom of the
channel. It can be a narrow strip of large
8-14
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stone, placed across tne channel, or it can
be a complete lining across the channel. The
structure causes the water to drop abruptly onto
a stabilized pad, thereby reducing tne effective
gradient.
2. The same materials used to construct revetments
are also used to build grade-control structures.
3. Common examples of grade-control structures
include riprap energy-dissipators, placed at
the outfall of stormdrains; riprap check dams,
which are placed at regular intervals along a
waterway; and ditches or other waterways lined
with some material such as riprap, concrete,
gabions, or Fabriform.
VII STORMWATER MANAGEMENT
A. The first basic principle of stormwater management
is: assure that the peak rate of runoff after
development is no greater than it was prior
to development.
B. In order to accomplish this, it will often be
necessary to hold back surface runoff, as close
as possible to the place where it originates, and
then release this water slowly enough so that it
will not damage streams.
1. Rooftop detention is often practical on
large commercial and industrial buildings.
The flat roofs are equipped with
8-15
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detention drains to store the water temporarily.
2. Parking lots can be constructed so as to detain
a large amount of water, temporarily.
3. Another method of reducing stormwater runoff
from parking lots and other paved areas, is to
use porous asphalt paving or surface the area with
crushed stone.
C. Recreation areas, such as parks and ball fields, can
temporarily store large amounts of runoff from ad-
jacent areas.
1. Creating permanent ponds, designed to store
stormwater, not only helps control the flow
of streams,during peak periods, but also adds
to the beauty of an urban environment.
2. Such ponds are equipped with devices that re-
lease water at a controlled rate.
D. One of the most popular structures for controlling
stormwater is the detention basin.
1. Detention basins store runoff when the flow is
at its peak, and release the stored water through
an outlet, at a controlled rate. These basins can
impound the water either temporarily or perman-
ently.
2. When the volume of water exceeds the storage
capacity of the basin, the excess runoff exits
through an emergency spillway located on the
edge of the basin.
3. After a storm, temporary basins slowly drain dry.
8-16
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E. Holding tanks are structures similar to detention
basins. They are built of concrete or metal, and
are located underground; these structures tempor-
arily detain runoff from parking lots or rooftops.
F. Infiltration systems have been used for years, to
control runoff. Infiltration systems consist of
holes in the ground, filled with coarse, clean
stone, or lined with bricks or perforated concrete
blocks.
1. These structures store stormwater and allow it
to infiltrate into the soil. The water, as it
slowly percolates, replenishes the groundwater.
2. The usefulness of infiltration systems depends
largely on the type of soils and the topography
at the site, as well as the location of the
groundwater table. A permeable subsoil is nec-
essary, to dispose of the water at an adequate
rate. Maintenance is very important.
G. Several types of stormwater controls involve the
stream channel or the stream channel and its flood-
plain. These controls detain the water or slow its
rate of flow, in order to reduce the peak rates of
runoff.
1. Some of these controls function within the
channel. One example of in-channel storage
and control is the exaggeration of a meandering
stream. By making a winding stream even more
winding, you increase the distance the water
8-17
-------
flows and reduce the rate at which it flows.
2. Another example of in-channel storage and control
is the use of check dams or wiers. These prevent
excessive erosion by reducing the rate of flow.
3. Another kind of stream channel storage is side-
channel storage. Side-channel storage is the use
of the flood plain on the sides of the stream
channel to store water temporarily during heavy
rains.
VIII MAINTENANCE
A. For stormwater management and other waterway ero-
sion control practices, maintenance is essential
if they are to continue to function over a long
period of time.
1. Check controls periodically, for evidence of
deterioration.
2. You should examine the plantings and structures
periodically. Any sign of weakness will require
corrective measures. Remove accumulated sedi-
ment and debris periodically, so that the struc-
tures for controlling stormwater will function
properly.
3. Fertilize the vegetated area regularly,so that
the plants in the waterways and around them will
continue to grow vigorously.
8-18
-------
Questions 1
Fill in the blanks.
1. The first basic method of controlling stream erosion
is to protect the ; and the second is by
the after a storm.
2. Most of the damage done to streams and other waterways
occurs during .
Proper practices and good
built to control erosion, will help as well.
4. Streams where the water only flows after a heavy rain
are called .
5. The force of running water is called force.
6. and are ways in which
water causes waterway erosion.
8-19
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Questions 2
Each of the following sentences contains one error. Write
the letter that corresponds to the incorrect word or phrase
in the blank provided.
The amount and rate of erosion you can expect in
a given waterway depends on several factors, in-
cluding obstructions in the channel; the turbulence
A B
of the flow of water; intermittent streams; the
B C
meandering of the stream; and bank materials.
D E
During periods of high water the velocity usually
A
increases. The water flows faster, the turbulence
A B C
decreases, and the flowing water scours the bed
C D
and erodes the banks of the stream.
D
Soils in which the particles are strongly bound to-
gether will erode more easily than soils made up of
A
loose grains. Larger materials, such as gravel,
B
cobbles or boulders will erode more slowly. Sand,
B C
silt, and clay particles will erode more rapidly
D
because they are lighter and more easily carried away
E
Water flowing over soils which contain a mixture of
materials, will sort the particles by size, until
A
the bottom is covered or "armored" with only the
B
8-20
-------
smaller materials. The water carries the small part-
C D
ides downstream, until the energy of the flow
D
decreases enough to allow them to settle out.
E
5. The gradient is the change in elevation of a stream,
A
frequently measured in feet of vertical change per mile of
B
horizontal distance. Generally the steeper the grad-
B
lent, the less rapid the erosion of the streambed.
8-21
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Questions 3
Circle the correct answer or answers.
1. Where man's activities have altered the natural watershed,
a number of factors will have an effect on the rate and
amount of erosion, including:
a. removal of natural vegetation
b. compaction of the soil
c. bank and bed materials
d. use of impervious materials
2. Channel realignment
a. is the process of installing water-holding tanks
b. increases the gradient
c. helps to control floodplain spillage
3. Before developing in a watershed, you should
a. consult the Standards and Specifications
b. study the streams to make sure they can handle the
higher rate of flow without causing erosion.
c. make as much room as necessary available for develop-
ment
d. construct revetments to control erosion
4. Effective and economical ways to protect streams against
excessive erosion from surface runoff include
a. reinforcements such as mulches and netting
b. check dams
c. clearing the area of vegetation
d. preserving a buffer strip of natural vegetation
5. Intermittent streams
a. require the planting of willows and alders along the
banks
b. are often planted with a cover of grass over the
entire flow area
c. need only a mulching of the soil with straw or hay
d. do not maintain a continuous flow
8-22
-------
Questions 4
Circle the correct answer or answers.
1. Before choosing a plant material for stabilizing a
stream you should consider several factors, includ-
ing:
a. the soil and soil moisture
b. exposure to sunlight
c. steepness of slope
2. Along ditches, swales, and other intermittent streams
plant vegetation
a. that is drought-resistant
b. that is attractive in the surroundings
c. in patches
d. that is moisture-tolerant
3. On bank slopes greater than 50%
a. vegetation should be planted profusely
b. slopes should be graded back
c. plant conventional grasses and legumes
d. plant alders and willows for extra protection
4. Grass waterways
a. are difficult to vegetate
b. need periodic maintenance
c. help prevent water from infiltrating into the soil
d. blend into the surrounding areas
5. Seeding
a. should be done only in permanently flowing streams
b. sometimes requires the use of mulches
c. is best employed in intermittent streams
d. can be employed almost any time of year
8-23
-------
Questions 6
Each of the following sentences contains one error. Write
the letter that corresponds to the incorrect word or phrase
in the blank provided.
Critical areas along streambeds which may need
structural stabilization include the outside of
A
bends, where the flow impacts against the stream-
A
bank; restrictions in the channel; junctions
~A B C
where tributaries enter the main channel; and
C
places where the channel gradient is excessively
D
low.
D
Stone riprap is used in constructing revetments
A
because its rough surface dissipates the energy
B
in the flowing water; it adjusts to changes in
C
the foundation resulting from erosion; and it aids
scouring along the lower edge or "toe."
D
Gabions are wire baskets filled with stone, used
A B
to hojxi back steep slopes and construct check
B C
dams. They are more flexible than revet mattresses
C D
or concrete.
Revet mattresses are concrete grids containing
A
several open spaces, which, when laid side by side,
can be used to pave parking areas as well as
B
8-25
-------
provide slope protection. They also allow more
C D
runoff to_infiltrate the soil, and can be filled
D E
with soil and seeded.
E
5. Grade control structures help control erosion of
A
the streambed by eliminating the hydraulic force
A B
of the water, by slowing the flow of the water,
B C
and by reducing the gradient.
D
8-26
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Questions 7
Fill in the blanks.
1. The first basic principle of stormwater management is:
assure that the peak rate of flow development
is no greater than it was development.
2. One method ot accomplishing stormwater management is to
surface runoff as close as possible to the
place where it •
3. Effective management of stormwater prevents the of
the amount of water flowing downstream. The rate at
which the water flows is also
4. Holding stormwater back also helps to control
downstream.
is often practiced on large
commercial and industrial buildings, as a means of storm-
water management.
6. To achieve control of stormwater on parking lots,
the size of the stormwater inlet and provide for
of stormwater on a part or the lot.
7. Another method of reducing stormwater runoff from parking
lots and other paved areas, is to use p
a paving.
8. Detention basins runoff when the flow is
at its peak, and release the water through an outlet, at
a c r
9. Holding tanks temporarily d_
from p 1 or rooftops.
8-27
-------
Questions 8
True or false.
1. Infiltration systems consist of holes in the
ground, filled with stone or brick; they store
stormwater and allow it to slowly infiltrate
the soil.
2. The usefulness of infiltration systems depends
largely on the type of soils, the topography,
and the groundwater table.
3. Infiltration systems are most useful at sites
where the groundwater table is consistently high,
and there is a large amount of water to be detained.
4. By making a winding stream even more winding, you
increase the distance the water flows and increase
the rate at which it flows.
5. Side-channel storage is the use of check dams
placed at intervals along the channel to reduce the
peak flow from the watershed.
6. When floodplain storage is used, you must construct
an emergency spillway to release flows that exceed
the amount of water the structure was designed to
hold.
7. Remove accumulated sediment and debris periodically
from stormwater control structures, so that they
will function properly.
8. Vegetated waterways do not require regular maintenance
once the vegetation has become well established.
8-28
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Questions 9
True or false.
1. Among the factors that effect the rate of
erosion in streams are turbulence, the degree
of meandering, the obstructions, and the vege-
tation present.
2. Improper channelization can result in flooding
further downstream.
3. Where conditions permit, new streams should be
stabilized with vegetation.
4. Stormwater management consists of the preser-
vation of a buffer strip of vegetation, along
natural waterways.
5. In intermittent streams it is generally suf-
ficient to plant only along the channel banks.
Sodding, sprigging, or seeding can be employed
in any streams provided that the plant mate-
rials are native to the area.
To prevent erosion under the netting, you can
secure straw much by anchoring at intervals along
the channel.
A grade-control structure consists of some durable
material placed on the bottom of the channel,
either in a strip across the channel, or in a com-
plete lining to reduce the effective channel gradient,
The same materials used to construct revetments
are also used to build grade-control structures.
8-29
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EROSION AND SEDIMENT CONTROL
TEMPORARY SOIL STABILIZATION
WORKBOOK
-------
CONTENT
I GENERAL INTRODUCTION
A. Definition of Temporary Stabilization
B. Temporary vs. Permanent Stabilization
C. Necessity of Temporary Stabilization in Certain
Situations
D. Factors Determining Allowable Delays between
Grading and Stabilization
II PROCEDURES AND PRACTICES
A. Compaction
B. Use of Plant Materials
1. Grasses
2. Legumes
3. Soil Conditions Necessary
C. Mulches
1. Straw, Hay, and Woodchips
2. Tacking with Asphalt
3. Use with Chemical Binders
4. Anchoring
5. Tracking
6. Netting
7. Woodchips
8. Other Materials
D. Chemical Soil Stabilizers
9-1
-------
Ill CHOICE OF PROPER STABILIZERS
A. Cost, How Long, How Well
B. Vegetative
C. Non-vegetative
9-2
-------
GENERAL INTRODUCTION
A. Temporary soil stabilization means protecting
the soil from excessive erosion, for a short
time. Usually, temporary stabilization is
designed to last for less than a year.
B. Permanent stabilization is done for long-time
use. For permanent stabilization, you establish
a ground cover with long-lived vegetation, or
cover the soil with concrete, asphalt, stone,
or some other durable material.
C. Temporary stabilization is often necessary
because grading operations frequently last
several months or more - sometimes for an
entire construction season.
1. During this period, the bare soil is
exposed to damage by wind and water.
2. And when the developer has finished
final grading, there is often a
period of time before the season is
right for permanent stabilization.
D. Of course, you have to consider how much temporary
stabilization will cost, and how much damage from
erosion and sedimentation will result, if you don't
stabilize the soil.
1. Factors determining how long a delay
may be allowed, before the soil must
be stabilized include the climate, the
topography, the erodibility of the soils,
and the sorts of protections against
erosion that exist, at the border of the
area being developed.
2. Because of all the factors involved,
determining how long a graded area may
be exposed is highly variable; usually
local or state agencies evaluate the
conditions, and decide how long graded
areas may be left uncovered.
II PROCEDURES AND PRACTICES
A. All fill material should be compacted, as a first
step in achieving temporary stabilization.
9-3
-------
B. Use of Plant Materials
1. For temporary soil stabilization, fast-
growing and hardy annual and perennial
plants, such as grasses, will provide
adequate protection.
a. Contour roughening improves the growth
of grasses and legumes, as well as
helping to slow the overland sheet
flow.
b. Annual grasses that are widely used
for temporary stabilization include
oats, sudangrass, wheat, and rye.
(millet, ryegrass)
2. Legumes such as clover are also useful for
temporary cover.
a. Not only do they provide temporary
cover, they also take nitrogen from
the air and add it to the soil, in
a form which can be used by other
plants.
b. Once homes have been built on a site,
the clover can be plowed under; plowing
this clover under enriches the soil
by adding organic matter. This helps
the growth of permanent vegetation.
3. Soil Conditions Necessary
a. On subsoil and even on some topsoils,
you will have to add fertilizers and
sometimes lime to the soil, before
plants will grow well.
b. For temporary stabilization, in such
cases, you need less fertilizer than
you do for permanent stabilization,
but it is still necessary.
c. For standard application rates, con-
sult the Soil Conservation Service
office, or the University
Agricultural Extension Agency.
d. Pay attention to the way you apply
lime and fertilizer. To get the
most out of the lime and fertilizer,
mix it with the soil to a depth of
3 to 4 inches.
9-4
-------
e. To reduce erosion, perform tilling
operations along the ground contour,
if needed and feasible.
f. The roughened surface will also
provide a better environment for seed
germination and plant establishment.
g. On slopes, you may also need to use
mulch on the seedbed, to reduce
erosion until the plant materials are
adequately established.
h. For further information, consult the
publication "Standards and Specifica-
tions for Soil Erosion and Sediment
Control in Developing Areas." This
publication, prepared by the Maryland
Soil Conservation Service, is invaluable
for anyone who wants information
about temporary vegetative stabili-
zation.
C. Mulches
1. Mulches shield the soil from water and wind.
The most popular mulches for temporary
stabilization are straw and woodchips,
especially straw.
a. When hay is substituted for straw,
remember that it may contain noxious
weed seeds.
b. The application rates for mulches used
for temporary stabilization are the same
as those for mulches used on seed beds.
1. As a rule of thumb the application
rate for straw or hay is about 3000 to
40UO pounds per acre.
2. For woodchips, 6O cubic yards per
acre.
c. On large areas, the usual way to apply
straw is to use a mulch blower. The
operator feeds straw bales into the
blower, which shreds the bales and
blows the straw onto the ground.
Correctly used, it covers a large
area evenly and rapidly.
9-5
-------
2. Liquid emulsified asphalt can be used
to bind the individual straws into a
resistant mat.
3. In areas where you don't want to use
asphalt, because it becomes sticky when
it is warm, use a chemical tack.
a. Various chemicals are available for
this purpose. For a partial list,
consult "Guidelines for Erosion and
Sediment Control Planning and
Implementation" or "Standards and
Specifications for Soil Erosion and
Sediment Control in Developing Areas."
b. These chemicals are binders, which are
diluted with water and sprayed onto the
straw with standard spraying equipment.
A hydroseeder can be used.
c. To aid the operator in judging whether
or not he has sprayed enough chemical
tack, a coloring agent may be added to
the solution.
4. Another method of anchoring straw is to use a
mulch-anchoring tool.
a. The mulch-anchoring tool is a special piece
of equipment, with a series of notched,
flat-sided circular blades.
b. When pulled over straw mulch, the blades
punch some of the straw into the ground,
leaving straw stems protruding from
the soil.
c. This technique of anchoring straw provides
even more protection against erosion, when
the crimping follows the contour of the
land.
d. The grooves and straw aid in controlling
runoff, by slowing the flow of the water
over the soil, and by increasing the rate
at which the water soaks into the soil.
9-6
-------
e. When anchoring follows seeding, it
improves seed germination and plant
establishment. The grooves conserve
moisture and nutrients and provide
depressions, which trap the seed
until it germinates.
f. However, the anchoring tool can only operate
on slopes up to three-to-one.
Tracking is a method of securing straw mulch
on slopes steeper than 3 to 1. This is
accomplished by running a cleated dozer up
and down the slope. In addition to anchoring
the mulch, this compacts the soil and pro-
vides horizontal depressions in the surface,
where rainfall and seed can collect; in this
manner the roughened surface helps prevent
erosion.
In highly critical areas, such as waterways,
nettings may be required to anchor the straw.
Woodchips are another mulch material used for
temporary stabilization.
a. They are also very effective as well as
economical/ but not cheap.
b. As you clear woodland areas, you can
salvage woodchips, or stockpile them
for later use.
c. Woodchips are an excellent material for
restoring the essential ground litter
in forested areas that have been damaged
by construction activity.
d. Sometimes woodfiber mulch, mixed with a
chemical binder, is used as a short-term
stabilizer. The mulch and the chemical,
together with water, are mixed in a
hydroseeder, and sprayed onto the soil.
Other Materials Used for Temporary Stabilization
in Highly Critical Areas.
a. Jute netting which is often used for
waterways.
9-7
-------
b. Excelsior blankets, which are often
used in areas exposed to concentrated
flows of water.
c. Ground-up corn cobs.
d. Gravel, or crushed rock.
Experts are taking a hard look at our
present techniques for controlling
erosion and sediment, and they are
continually coming up with new methods
and products that will work better and
cost less. We have to be constantly
on the alert for new developments in
the field of erosion and sediment con-
trol.
D. Chemical Soil Stabilizers
1. A partial list of these would include
AEIrospray 52 binder®, Curasol AE® and
AH® and Terratack®
2. These products are all water emulsions, and
are supplied as liquids or concentrates.
3. These chemicals are relatively easy to use.
They are simply mixed in a hydroseeder and
sprayed onto the soil. Other standard
sprayers can also be used.
4. The chemical stabilizers coat the soil
surface temporarily, shielding it from
damage by water and wind; they may also
penetrate the soil to bind the particles
into a mass that resists erosion.
5. The effectiveness of chemical stabilizers,
however, will vary from site to site, de-
pending on the soil conditions, the
climate, and the slope steepness.
6. The texture and moisture content of the
soil will determine how far into the soil
the diluted chemical will penetrate, and
how effectively it will bind the soil.
9-8
-------
7. Proper dilution rates and application
rates will vary, depending upon the soil
texture, the climate, the way the site
is used, and the topography.
8. To avoid expensive mistakes, when you
use chemical soil stabilizers, spray a
test plot with a recommended mixture
and application rate, and examine the
results, before you spray the entire
site. If the soil and slope conditions
vary from place to place on one large
site, use several test plots.
9. You should keep an open mind about
chemical soil stabilizers. Although
one of the chemical stabilizers may
fail miserably, another may work very
well. Also, remember that many of the
products are being continually improved,
and that new products are being developed,
III CHOICE OF PROPER STABILIZERS
A. Cost will be a major consideration, but you also
have to consider how well the materials work, and
how long they will have to keep working.
B. Vegetative
1. Properly established, vegetation is an
effective and durable soil stabilizer.
2. The type of vegetation to be used will
depend on the season when planting will
occur, and the length of time that pro-
tection will be required.
a. For example, winter wheat and rye
will provide excellent protection
if they are planted in the fall.
b. Other grasses will be better suited
for spring and summer.
c. Most annual plants provide protection
for only one growing season. If pro-
tection must extend into another
growing season, a perennial plant
material is usually needed.
9-y
-------
Some temporary plant materials, such as
weeping lovegrass, are also used
for permanent stabilization. If an
adequate cover of such a grass can be
established in an area which has been
final-graded, even though the planting
may take place during a season when
regulations do not permit permanent
planting, there is no reason to plow
the cover under and reseed.
a. Top dressing with additional
quantities of fertilizers and
lime may be the only operation
necessary before final acceptance
of the work.
C. Non-vegetative
If you decide against plants, the kind of
non-vegetative temporary soil stabilization
you use will depend on the effectiveness,
the cost, and the length of time the
temporary stabilization must last.
Straw vs. Woodchips
a. Straw and woodchips work equally well,
but one may be less expensive than the
other, or more readily available.
b. Woodchips last longer than straw, as
a temporary stabilizer. As a general
rule, straw will function up to six
months or more, whereas woodchips
will function for a year or longer.
Some applications of chemical stabilizers will
only be effective for a few weeks; others may
last for months. There is not enough informa-
tion about chemical stabilizers to be more
specific. This is especially true, because
soils and terrains are so different.
9-10
-------
Questions 1
Mark the statements true or false.
1. Temporary soil stabilization means protecting the
soil from excessive erosion, for a short time.
2. Temporary stabilization is designed to last for
several years.
3. Temporary stabilization is often necessary, because
grading operations rarely leave bare soil exposed for more
than a week.
4. Factors that determine how long a delay may be allowed,
before the soil must be stabilized include climate, topography,
the erodibility of the soils, and the protections that exist.
5. When a developer has finished final grading, there is
often a long period of time before the season is right for
permanent vegetative stabilization, or before paving can be
laid.
9-11
-------
Questions 2
Fill in the blanks.
1. All fill material should be as a first step
in achieving temporary stabilization.
2. For temporary stabilization, fast-growing and hardy
annual and perennial , such as grasses, will
provide additional protection.
3. improves the growth of grasses
and legumes, as well as helping to slow overland sheet
flow.
4. Annual grasses that are widely used for temporary stabiliza-
tion include , , and .
5. such as clover are also useful for temporary
cover.
6. Not only do they provide temporary cover, legumes also take
from the air and add it to the soil, in a form
which can be used by other plants. is an
essential plant nutrient.
7. Once homes have been built on a site, the clover can be
plowed under; plowing this clover under the
soil by adding matter.
9-12
-------
Questions 2 Continued
8. On subsoil and even on some topsoils, you will have to
add and to the soil, before
plants will grow well.
9. For temporary stabilization, in some cases, you will
need less than you do for permanent
stabilization.
10. To reduce erosion perform tilling operations along the
ground as needed and feasible.
11. On slopes, you may also need to use on the
seedbed, to reduce erosion until the plant materials are
adequately established.
12. The most popular mulches for temporary stabilization are
. and .
13. As a rule of thumb, the application rate for straw or
hay is about pounds per acre. For woodchips
cubic yards per acre.
14. On large areas, the usual way to apply straw is to use
a
9-13
-------
Questions 3
Circle the correct answer or answers.
1. For tacking mulches, you can use
a. liquid emulsified asphalt
b. polyvinyl chloride
c. various chemical binders
2. To aid the operator in judging whether or not he has
sprayed enough chemical tack a coloring agent may be
added to the solution. (T or F)
3. Another way to secure straw mulch is
a. to apply a thin layer of topdressing
b. to anchor it with a mulch-
anchoring tool
c. to compact it with a sheep's foot roller
4. Anchoring
a. should run up and down the slope
b. should follow the contour of the ground
c. creates grooves that aid in controlling runoff
d. improves seed germination
e. can be performed on any slope
9-14
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Questions 3 Continued
5. Tracking
a. is a recommended method of securing straw on
slopes flatter than 3 to 1
b. is an approved method of securing straw on
slopes steeper than 3 to 1
c. is accomplished by running a cleated dozer
along the contour of the slope
d. is accomplished by running a cleated dozer up
and down the slope
6. In highly critical areas, such as waterways, to
anchor straw mulch, use
a. chemical binders
b. nettings
c. liquid emulsified asphalt
d. anchoring
7. Woodchips
a. are effective and economical mulch materials used
for temporary stabilization
b. should only be used on wooded sites
c. are excellent for restoring the essential ground
litter
8. Other mulch materials include
a. crimping
b. jute netting
c. top soil
d. excelsior blankets
e. ground up corncobs
f. fill
g. gravel or crushed rock
9-15
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Questions 4
Fill in the blanks.
1. Chemical stabilizers have come into major use in the last
few years. Chemical stabilizers coat the soil surface
temporarily, it from damage by water and wind;
they may also penetrate the soil to the particles
into a mass that resists erosion.
2. The effectiveness of chemical stabilizers will vary from
site to site, depending on the ,
the and the slope
To avoid expensive mistakes, when you use chemical soil
stabilizers, spray a with
the recommended mixture and application rate,and examine
the result, before you spray the
If the soil and slope conditions vary from place to place
on one large site, use
9-16
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Questions 5
Mark the statements true or false.
1. _ Cost will be a major factor in determining which
form of temporary stabilization to use.
2. _ You don't need to consider how well the materials
work, or how long they will have to keep working.
3. _ Properly established, vegetation is the most
effective and durable soil stabilizer.
4. _ Any plant can be used, during the spring, summer,
and fall.
5. _ Winter wheat and rye will normally provide excellent
protection if they are planted in the fall in areas of
adaptation.
6. _ Most annual plants provide protection for several
growing seasons.
7. _ No plants used in temporary stabilization are used
for permanent stabilization.
If you decide against plants, the kind of non-
vegetative temporary soil stabilization you use
will depend on the effectiveness, the cost, and
the length of time the temporary stabilization
must last.
9-17
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Questions 5 Continued
9. Straw and woodchips work equally well, but one
may be less expensive than the other, or more
readily available.
10. Straw lasts longer than woodchips.
11. Some applications of chemical stabilizers will
only be effective for a few weeks; others may
last for months.
9-18
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Questions 6
Circle the correct answer or answers.
1. Temporary stabilization is designed to last
a. for more than a year
b. for less than a year
2. Usually, the maximum length of time a graded area may be
exposed
a. is six months
b. can be determined by the contractor
c. is determined by state bureaus or local agencies
3. One of the best ways to stabilize areas temporarily is
to use fast-growing annual or perennial plants, such as
grasses; these grasses include
a. Kentucky 31 tall fescue
b. oats
c. clover
d. wheat
e. Sericea lespedeza
f. Sudangrass
g. rye
4. Legumes
a. are sometimes useful for temporary cover
b. add nutrients to the soil
h. rye grass
i. weeping lovegrass
9-19
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Questions 6 Continued
5. The most popular mulches are
a. corncobs
b. straw
c. hay
d. Kentucky 31 tall fescue
e. woodchips
6. On large areas, the usual way to apply straw is
a. with a mulch blower
b. with a rake
7. Mulches require tacking on large areas. This can be
done with
a. seeding
b. liquid emulsified asphalt
c. chemical binders
d. fertilizer and lime
8. The choice of methods will depend on
a. cost alone
b. effectiveness, cost, and length of time
c. state regulations
9-20
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EROSION AND SEDIMENT CONTROL
CONTROL OF SEDIMENT
GENERATED ON
CONSTRUCTION SITES
WORKBOOK
-------
CONTENT
I. BASIC PRINCIPLES OF CONTROLLING SEDIMENT
II. VEGETATIVE PRACTICES
A. Natural Vegetative Buffers
B. Graded Buffers
C. Contour Stripping
D. Woodland Areas
E. Sod Inlet Filters
III. STRUCTURAL PRACTICES
A. Filters and Dikes
1. Gravel Inlet Filter
2. Interceptor Dike
B. Sediment Traps
1. Sandbag Trap
2. Straw Bale Trap
3. Straw Bale Barrier
C. Sediment Basins
1. Dry
2. Wet
IV. REVIEW QUIZ
10-1
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I. BASIC PRINCIPLES OF CONTROLLING SEDIMENT
A. Erosion control is the first line of defense.
It reduces the amount of sediment that will be
generated.
B. Sediment control is the second line of defense.
It prevents much of the sediment from uncontrolled
soil erosion from leaving the construc-
tion site.
C. Sediment traps are designed to slow the flow
of water. This reduces the ability of the water
to transport sediment, and the sediment settles
out of suspension.
D. The amount of sediment removed from the runoff
is dependent upon these three factors:
1. Speed that the water flows through the trap.
2. Length of time the water is detained.
3. Size and weight of the sediment particle car-
ried into the trap.
The slower the flow of water and the longer it
is detained, the greater will be the quantity of
sediment deposited. The size and weight of the
sediment particles determine the speed at which
they settle out of suspension. The larger and
heavier a particle, the faster it settles out.
10-2
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E. Efficiency of sediment trapping is expressed as
the percent of sediment removed from the runoff,
Amount trapped
% Ef f'iciency= x 100
Total Load
II. VEGETATIVE PRACTICES
A. Natural Vegetative Buffers
1. A vegetative buffer at the base of a steep
slope is an effective means of trapping sed-
iment .
2. This involves maintaining a strip of natural
vegetation along the sides of a stream to
slow and filter overland flow coming from
higher-lying graded areas.
3. This is one of the more effective and eco-
nomical methods of removing small amounts of
sediment from overland flow.
4. Except for essential roadway crossings, no
construction should be allowed within the
buffer area.
B. Graded Buffers
1. Provisions for construction must be made dur-
ing early design stages of development.
2. The flatter and longer it is, the more sedi-
ment it will retain.
10-3
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3. A positive grade of at least two percent
should be provided to prevent ponding.
4. Timely establishment of vegetation on the
buffer is a must in order to provide eff-
ective sediment trapping.
C. Contour Stripping
1. A method borrowed from the farmer.
2. It is used to break the flow of runoff on
long hillsides.
3. It involves the establishment of strips of
vegetation, usually grass sod, along the
ground contour at regular intervals on the
slope.
4. These strips slow the flow and reduce the
amount of runoff, thus reducing erosion and
trapping much of the sediment generated
from erosion occurring between the strips.
D. Woodland Areas
1. Woodland litter can provide a high degree
of filtering action as well as aiding in
the absorption of runoff, but care must be
exercised because the deposition of a few
inches of sediment around a tree can cause
it to die.
10-4
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2. Use woodland areas only for the filtering
of overland flow.
E. Sod Inlet Filter
1. Made up of strips of sod placed around the
storm drain inlet.
2. The grass slows the flow of water into
the inlet and filters out some of the
sediment.
3. The size of the sodded area is varied
depending upon the amount of runoff and sediment ex-
pected at the inlet. The larger the sodded area,
the more effective it is.
4. This practice should only be used to
handle light concentrations of sediment and low
rates of runoff.
5. Best used after final grading is complete
and during the establishment of a vegeta-
tive cover.
III. STRUCTURAL PRACTICES
A. Filters and Dikes
1. Gravel Inlet Filter
a. Used at storm drain inlets.
b. Made of coarse gravel or crushed stone.
c. Will temporarily impound runoff.
10-5
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d. Provides a negligible amount of filter-
ing action.
e. Is highly resistant to erosion.
f. Standard concrete building blocks
are placed on the inside of the gravel
filter to keep stones from being washed
into the storm drain inlet.
g. The configuration of the filter will
depend upon the type of inlet being
protected.
h. Prompt maintenance is very essential.
10-6
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B. Sediment Traps
1. Sandbag Sediment Trap
a. A quick and economical method of tempor-
arily disrupting flow and trapping the
coarser sediment particles.
b. A small degree of sediment control can
be achieved by positioning these barri-
ers at regular intervals along the ditch.
c. Bags are filled with soil or sand and
stacked in an overlapping fashion which
provides additional strength for resist-
ing the force of the flowing water.
d. Undercutting is a major cause of the failure
of many sandbag sediment traps.
e. The sandbags should be set in a trench
at least six inches in depth. This will
greatly reduce the chance of undercutting
failure.
f. Inspection and prompt maintenance is required,
2. Straw Bale Sediment Trap
a. Fast and economical temporary trap.
b. Made of bales of straw or hay.
c. Deteriorates rapidly.
d. Can slightly increase durability by using
wire-tied bales.
10-7
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e. When constructing the trap the bales are laid
on their sides and staked into place.
d. Undercutting can render the trap ineffective.
f. Straw bale trap should be entrenched
at least six inches and excavated soil should be
compacted along the upstream face.
g. Inspection and prompt maintenance is re-
quired ,
3. Straw Bale Perimeter Barrier
a. Used to provide a sediment barrier
along the downhill perimeters of small
graded sites where area restrictions
or other factors prevent the use of
other practices.
b. Close inspection is required.
4. Excavated Sediment Trap
a. Its function is to temporarily detain
the runoff and thereby allow some sed-
iment to settle out.
b. Costs little to construct.
c. Once the sediment-yielding area is sta-
bilized, the pit area can, in some instances,
be filled in with soil and covered with sod.
10-8
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C. Sediment Basins
1. Sediment basins are the most effective
structures for trapping sediment.
2. Used on construction sites where
concentrations of both runoff and
sediment are anticipated.
3. Dry Sediment Basin
a. Designed to only temporarily impound
runoff during rainfalls.
b. It is drained by a standard metal
riser pipe with 1/2" perforations which
allow the water to be released at a
controlled rate.
c. It requires a formal design for size
and safety reasons.
d. Only suitable soils must be used to
construct the dam.
e. A high degree of compaction must be
achieved.
f. Proper positioning of the riser pipe
is essential to proper performance.
g. Piping failures are too common in tempor-
ary dry sediment basins.
10-9
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h. Consult state and local regulations
governing their design and construction
prior to starting to build one.
i. Periodic cleaning is essential if the basin
is to do its job.
(1) usually cleaned with a backhoe or
dragline
(2) smaller basins with firm founda-
tions are sometimes cleaned with
front-end loaders
j. Construction specifications for the ba-
sin must specify the required freeboard -
the vertical distance between the
design high water and the top of
the dam.
k. Failing to provide enough freeboard may
result in overtopping during heavy
storms and breeching of the dam.
Wet Basin - Sediment Pond
a. Used when it becomes necessary to dam
permanent streams in order to trap sedi-
ment.
b. On large residential developments, re-
creational impoundments also function as
sediment traps.
10-10
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c. Requires a formal design and strict
construction control for safety
reasons.
d. Cleaning a wet sediment basin is costly,
(1) dragline is used.
(2) portable dredges used on large
ponds.
10-11
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QUESTIONS 1
Fill in the blanks
1. E c is the first
line of defense. It the amount of
sediment that will be generated.
2. S c is the second
line of defense.
3. Sediment traps are designed to slow the flow of
4. The amount of removed from the
runoff is dependent upon three factors:
a. S that the water flows
through the t
b. L of time the water is
c. S__ and w of the
sediment particles carried into the trap.
10-12
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Multiple Choice
1. The best vegetative filters are
a. legumes b. grasses
c. trees d. periwinkle.
answer(s)
2. No construction should be allowed within a buffer
area
a. at all.
b. except for essential roadway construction.
c. except for residential construction.
d. except for normal roadway construction.
answer(s)
True or False
1. Leaving a buffer at the base of a steep
slope is an effective means of trapping small amounts of
sediment.
2. A buffer speeds the flow of runoff coming
off a steeper slope.
_3. The flatter and longer a buffer area, the
more sediment it will retain.
4. Adding vegetation to a buffer area increases
its ability to trap sediment.
5. To prevent ponding, i positive grade of at
least two percent should be provided.
_6. A natural vegetative buffer is one of the
more effective and economical methods of re-
moving amounts of small sediment from overland
flow.
10-13
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1. Contour stripping is a method borrowed from
a. the farmer. b. the contractor.
c. nature. d. the foreman.
answer(s)
2. The use of a vegetative buffer near the base of
a highway slope serves th2 same function as
a. the storm drain.
b. the top of cut.
c. the interceptor dike.
d. the contour strips.
answer(s)
3. The sod inlet filter
a. should only be used to handle light concen-
trations of sediment.
b. is made up of pads of sod.
c. is best used after final grading is complete.
d. all of the above.
e . none of the above.
answer (s)
10-14
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QUESTIONS 4
Fill in the blanks
1. S p are employed on
construction sites to trap sediment.
2f The filter is used at
storm drains.
3. The gravel inlet filter is h r
to erosion.
4. The configuration of the filter will depend upon
the t of i being protected,
10-15
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QUESTIONS 5
True or False
1. The sandbag sediment trap is a quick and
economical method of temporarily disrup-
ting flow and trapping the coarser sedi-
ment particles.
2. Undercutting is a major cause of failure of many
temporary sediment traps.
_3. Straw bale sediment traps last indefinitely.
4. Close inspection is not required of a straw
bale perimeter barrier.
5. The function of an excavated sediment trap
is to temporarily detain the runoff.
6. The most effective structures for trapping
sediment are straw bale barriers.
10-16
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Multiple Choice
1. A dry sediment basin is
a. designed to only temporarily impound runoff,
b. drained by a metal riser pipe.
c. requires a formal design.
d. all of the above.
e. only a and c.
answer(s)
2. The vertical distance between the top of the dam and
the design high water within the basin is known as the
a. sediment valve.
b. freeboard.
c. safety factor.
d. ruler.
answer(s)
3. The device at the top of the riser pipe
is called
a. a barrel.
b. an antivortex device and. trash rack.
c. an emergency spillway.
d. none of the above.
answer(s)
10-17
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QUESTIONS 7
1. Erosion control r the amount of sediment
that will be generate?.
2. Sediment control is the s line of defense.
3. The three factors upon which the amount of sediment
removed from the runoff is dependent are:
a. S that the water flows throuoh t.he
b. L of time the water was d
c. S and w of the sediment
particles carried into the trap.
4. Leaving a v b at the base of
a steep slope is an effective means of trapping
sediment.
5. M ^ a natural buffer is one of the
more effective and economical methods of removing
small amounts of sediment from overland flow.
6. The ability of a graded buffer area to trap sediment
is improved by adding v .
7. The L^st vegetative filter is
8. Woodland areas should be used only to filter
o flow.
9, £ s is a method
borrowed from the farmer.
10. It ir. used to break the f of r_
on long hillsides.
10-18
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11. The use of a v b near the
base of a highway slope serves the same function
as strips.
12. G b are employed on
construction sites to retain or trap sediment.
13. The sod inlet filter should be used to handle
1 concentrations of sediment.
14. The 2 i filter is highly
resistant to erosion.
15. The configuration of the filter will depend upon
the t of i being protected.
16. The interceptor dike is used on r
rights'of way to divert flow onto vegetated areas.
17 . Straw b and s traps are
quick and economical methods of temporarily dis-
rupting flow.
18. u is a major cause of the failure
of many temporary sediment traps.
19. Undercutting is reduced in temporary sediment
t by placing either the s
traps or s ^__^ b traps a minimum
of inches in the ground.
20. A straw bale perimeter barrier is used to provide
a s barrier along the downhill peri-
meter of small graded sites, where area restric-
tions or other factors prevent the use of other
practices.
21. An e sediment trap c_
1 to construct.
10-19
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22. S b are the most effec-
tive structures for trapping sediment.
23.
23. A dry sediment basin is designed to only t_
impound r during and for a short time after
rainfalls.
24. A dry sediment basin is drained by using a standard
metal r p with p_
which allow the water to be released at a controlled
rate.
25. Both wet and dry sediment ponds must be
a. vegetatively stabilized.
b. emptied.
c. washed.
d. none of the above.
answer(s)
10-20
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EROSION AND SEDIMENT CONTROL
EROSION AND SEDIMENT
CONTROL PLANNING
WORKBOOK
-------
CONTENT
I. NECESSITY OF EROSION AND SEDIMENT CONTROL PLANNING AND
IMPLEMENTATION
A. Eliminates Many Potential Problems
B. Protects the Landscape
C. Protects Critical Areas
II. RESPONSIBILITIES OF PRELIMINARY PLANNING
A. Specify Proper Grading Practices
B. Control Runoff on the Site
C. Minimize Grading
III. THE PRELIMINARY STUDY
A. Each Lanscape is Unique and Imposes Different
Restrictions
B. The Impact of Erosion and Sediment on the Site and
Adjacent Areas must be Determined
C. Evaluate Critical Features
IV. THE DESIGN STAGE
A. Follows Preliminary Study
B. Proper Siting of Structures Reduces Damage
C. Procedures and Responsibilites of the Owner and Developer
V. THE COSTS OF CONTROLLED VS UNCONTROLLED DEVELOPMENT
A. Disposal of Sediment Generated
B. Cost of Setting-Up and Following Erosion and
Sediment Control Plan
C. Preparation of Good Plans at Lowest Practical
Cost of Execution
11-1
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VI. SOURCES OF INFORMATION FOR SITE PLANNING IN RELATION
TO EROSION AND SEDIMENT CONTROL
A. Soil Conservation Service
B. U.S. Geological Survey Offices
C. Highway Offices
D. County Planning Boards
E. Local Planning and Zoning Agencies
F. State Department of Natural Resources
G. Historical Reports
H. Regional Land Use Plans
VII. TOOLS USED IN PLANNING PROCESS
A. Topographic or Base Map
B. U.S.G.S. Quadrangle Maps
C. Aerial Photographs
VIII. GOALS OF SITE PLANNING
A. Minimize Damage to Land
B. Five Key Requirements of Erosion and Sediment
Control Planning
IX. IMPORTANT ASPECTS OF EROSION AND SEDIMENT CONTROL PLAN
A. Each Plan Must Fit Individual Site
B. Basic Features
11-2
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I. NECESSITY OF EROSION AND SEDIMENT CONTROL PLANNING AND
IMPLEMENTATION
A. As we reshape the land, for urban or industrial
uses, erosion and sedimentation problems often
result, which could have been avoided, with
proper planning and implementation.
B. In any erosion and sediment control plan, you
will try to protect the landscape.
1. As the population of the United States in-
creases , landscapes come under more and more
pressure. In the last 200 to 300 years, much
of the land has been converted from its
natural state to farms and cities, or
suburbs.
2. If we continue to transform natural landscapes
at an ever-increasing rate, we may speed up
the rate of soil loss, and, as a result,
damage our land and water.
C. Certain types of landscape are more easily damaged
than others.
1. Critical areas include forests. We should
make every effort to preserve as much forest
land as possible, and to protect forest land
that is being developed.
2. Another critical area is the floodplain, an
area of land on either side of a channel that
is nearly level and is subject to periodic
11-3
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flooding. Floodplains are important
because they store excess runoff temporarily,
thus helping to avoid problems further
downstream.
3. Steep slopes are critical. Within certain
watersheds there often are areas where the
soil is subject to droughts, sliding, and
erosion. Such soils are particularly
susceptible to damage, but nearly all soils
on steep slopes are likely to erode if they
are unprotected.
4. Wetlands occur in many parts of the country.
These areas are extremely valuable as
drainage basins, for flood and sediment
control, and for the preservation of wildlife
resources. They are the critical link in the
aquatic food chain.
5. Another critical area is the shoreline of
bays and large inland lakes. We must take
care to protect these areas from wave action.
6. Waterways and streams, whether or not they
are navigable, are other critical areas.
Good planning is necessary to avoid excessive
erosion and sedimentation.
7. Any man-made impoundment, such as a reservoir,
11-4
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is a critical part of the landscape and
must be protected from sediment.
II. RESPONSIBILITIES OF PRELIMINARY PLANNING
A. One of the main principles of site planning is
to see that there is a minimum of grading
and that it precedes in an orderly manner.
1. Grading operations can greatly change the
natural arrangement of soil particles.
One of the major causes of this alteration
is compaction.
a. Of course, there are many ways to
restore the structure of a soil once
it has been lost, but soil compaction
still presents a problem. Many years
of diligent effort on the part of soil
bacteria and other living things, like
earthworms and grass roots, plus
materials such as nitrogen and oxygen
are required to get the soil back to
its previous condition.
b. Clearing and grading have other effects,
too. Once the protective vegetative
cover has been stripped away, the soil
is exposed to the erosive or dispersive
action of water and wind.
11-5
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B. In most areas of the country, heavy rainstorms
are most frequent from May to September. This
is also the time when construction activity
is most intense. Therefore, this is the time
when exposed soil is most likely to be badly
eroded.
1. As the intensity of rainfall increases,
water collects on the soil surface and
flows downslope, as surface runoff.
2. On steeply sloping areas, large amounts of sand,
silt, and clay particles are dislodged and
carried off in sheets of water moving
down the newly-exposed slopes.
3. On slopes that are not as steep, the
rainfall carries off smaller amounts of
soil.
C. One of the key strategies in erosion and sediment
control planning is to see to it that runoff
water is controlled on the site.
1. Diversion structures often can help control
the runoff.
2. Water concentrated in waterways can be
controlled with ponds, with check dams,
and with other structures.
D. Another key strategy is to minimize grading.
1. To minimize grading, develop the land
11-6
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along the natural contours of the ground
surface.
2. Wherever possible, plan the grading so as
to minimize slope length and limit the
amount of area exposed at any time.
3. How much soil the moving water will dislodge
and carry away depends on the resistance of the
soil particles to dispersion, and on the speed
and volume of water moving over the soil.
4. We can increase the resistance of soil to dis-
persion, while construction takes place, and
also control the volume and velocity of the
water, as it moves over the soil and concentrates
in waterways.
III. THE PRELIMINARY STUDY
A. Each site has its own earth history and character,
Not only do the plants, animals, and human beings
vary, from place to place, on the surface of the
earth, so do the bedrock, the soils, and the
topography. Each landscape, in turn, imposes
certain restrictions on the way it can be
developed.
B. Before development commences, the developer must
determine the impact that erosion and sediment,
11-7
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produced during and after the work, will have
on his own site, and on the areas lying downslope
and downstream from the site.
1. This requires a preliminary study of the
land, including its use, soils, topography,
climate, and the general nature of the
watershed.
2. The developer should evaluate the present
uses of other upstream areas in the
watershed, and the potential for future
expansion in these areas.
3. Local zoning and planning officials must take
considerable responsibility to insure that
the developer knows the plans for future
expansion in these areas. These officials
must set adequate standards, and enforce
them, to protect the present and future
conditions of the region.
4. Comprehensive planning, involving all of a
given watershed, is essential to insure
that adequate erosion and sediment control
planning is achieved.
C. In making a preliminary study, look for critical
land features and evaluate them. These include
waterways and their floodplains, steep or long
slopes, soils which may be highly erodible,
droughty, or of low fertility, tree stands,
11-8
-------
and areas with high groundwater tables. Include
provisions for stormwater management.
IV. THE DESIGN STAGE
A. After the preliminary study has been made, the
design stage of development begins. Roadways,
utilities, buildings, and other structures
are located, designed, and shown on a site
plan during this stage.
1. These plans will show what is to be con-
structed, where it is to be constructed,
and how it will be constructed.
2. As with the preliminary study, the
developer must have the critical land
features assessed at the outset of the
design stage of construction, so as to
minimize disturbance to these features.
3. Much of the information on erosion and
sediment control, which was gathered during
the preliminary study, can be used in the
final design plans. However, you should
gather more detailed information, both
from literature and field studies.
11-9
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B. The proper siting of structures can reduce
erosion and sediment damage; when it is
possible, locate these structures in order to
minimize grading, so as to reduce erosion.
1. The designer cannot totally prevent erosion
and sedimentation. It is necessary to
develop an erosion and sediment control
plan, as part of the overall site develop-
ment plan.
2. This plan shows the necessary procedures
and measures which the developer must take,
to eliminate excessive erosion and sediment
damage.
C. Erosion and sediment control planning and design,
as it relates to construction, is a relatively
new discipline.
1. Therefore we must rely a great deal on
those people who have on-the-ground
construction experience.
2. It is essential that the inspector and the
foreman be able to interpret erosion and
sediment plans, prepared for specific sites.
D. Procedures
1. The owner or site developer is responsible
for the preparation of the erosion and sediment
control plan.
11-10
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a. He may call upon competent engineers,
architects, scientists, and other
qualified people, to engage in the prep-
aration of the plan.
b. The plan must then be approved by an
authorized approving office, whereupon
a grading permit is issued to the owner.
2. The owner must also notify the inspector's
office, usually about two working days in
advance, of his intent to begin clearing
and construction work described in the
erosion and sediment control plan.
3. The owner must have both the official
grading permit and the erosion and
sediment control plan on the site
during grading and construction.
a. The developer has the responsi-
bility to implement the plans,
as well as to have them on hand.
11-11
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V THE COSTS OF CONTROLLED VS UNCONTROLLED DEVELOPMENT
A. Based on 1974 prices, removal of soils from
reservoirs can cost $2 or more per cubic yard;
from streets, $8 per cubic yard; and from storm
sewers, $100 per cubic yard. Removal of clay
particles and other materials from municiple
water supplies can cost $25 or more per cubic
yard.
1. Soils washed off building sites can damage
structures, waterways, wildlife, and scenic
values. The disposal of these scenic values
once they are removed, becomes an additional
cost.
B. For a 10 acre site, experience has shown that the
cost of setting up and following an erosion and
sediment control plan, including the cost of build-
ing sediment basins, stabilizing exposed soil with
mulch and grass, and following up with maintenance,
averages $1500 or more per acre, depending on phy-
sical and climatic factors, as well as the size of
the area.
1. This cost is minor compared with the price of
uncontrolled development. For example, the
cost of removing 200 cubic yards of sediment
from storm sewers alone will range from
$12,000 to $30,000. And it's
11-12
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not unusual for an acre of exposed soil
to yield 200 cubic yards per year.
C. The planner must prepare good plans at the
lowest practical cost of execution. Owners
and developers can render real service by
developing sites so that drainage is good,
the slopes are moderate, and the area resists
erosion to a maximum extent.
VI. SOURCES OF INFORMATION FOR SITE PLANNING IN RELATION
TO EROSION AND SEDIMENT CONTROL
A. Soil survey reports furnished by the Soil
Conservation Service provide information on
the suitability of various soil types for
locating pipelines, roads, ponds, reservoirs,
drainage systems, etc.
1. The exact location of woodlands, wetlands,
and other critical areas can be obtained
from aerial maps and photographs furnished
by the Soil Conservation Service.
B. U.S. Geological Survey Offices in most states
provide information on the location of important
mineral deposits, critical underground water
supplies, the location of rock outcrops, and
other pertinent items.
11-13
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C. Highway offices at the county and state level
provide information on the location of present
and future highways.
D- The Soil Conservation Service and county planning
boards can furnish information on soil engineering
properties and areas having drainage or flooding problems
E. You can obtain information on local
ordinances from local planning and zoning
agencies.
F. You can obtain information on new regulations
pertaining to erosion and sediment control from
the State Department of Natural Resources or
other agencies responsible for water pollution
control. These offices can also provide updates
on technical information required by developers
and planners.
G. Historical reports in county libraries provide
other useful information.
H. Don't overlook regional land use plans for various
watersheds.
VII. TOOLS USED IN PLANNING PROCESS
A. One of the most important maps for site planning
is the topographic or base map.
1. Most base maps prepared for site development
have a scale in the range of 40 to 200 feet
11-14
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per inch, and contour intervals of two
to five feet.
B. For preliminary site evaluations, the quadrangle
maps prepared by the United States Geological
Survey are often useful.
1. They generally have a scale of 1320 feet per
inch and a contour interval of 2O feet.
C. Often an enlarged aerial photograph or stereoscopic
pairs of air photos giving a three-dimensional
persepctive, are useful for locating woodlands,
wetlands, and other critical features.
1. When these critical locations have been
delineated on a base map, the planner can
begin to design the site development plan,
including the erosion and sediment control
plan.
2. During on-site studies, you can consult with
staff persons of the soil and water conserva-
tion district, members of the State Natural
Resources Department, representatives of
City Departments of Public Works, and other
public officials.
3. For problems that are particuarly difficult,
it is often desirable to retain a professional
consultant. Public agencies having responsi-
bility for erosion and sediment control can
generally furnish names of competent consultants
11-15
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VIII. GOALS OF SITE PLANNING
A. One of the prime goals of site planning is to
organize construction in such a way as to
minimize damage to the land.
1. The best erosion and sediment control is
one that works closely with nature.
B. Five Key Requirements of Erosion and Sediment
Control Planning.
1. Identify and protect critical features.
a. Delineate critical features on the base
map, before construction begins. The
physical factors of the landscape,
soils, drainageways, woodlands, and
wetlands, taken together, should help
determine the layout and design of
the development.
b. The proposed construction and its
location with respect to critical
areas should help determine what
measures must be taken to control
erosion and sediment.
2. Soil should be kept on the site by reducing
erosion and runoff. By keeping the soil
on the site, we reduce sediment pollution.
3. The third requirement of an erosion and sediment
control plan is: trap sediment.
11-16
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4. The fourth requirement of a plan is: stabilize
the soil.
5. The final requirement of any plan is inspection
and maintenance.
a. Even the best-designed erosion and sediment
control plan will be a wasted effort, if
the owner or his representative fails to
inspect and maintain all measures on a
day-to-day basis.
b. Where sediment control or stormwater
management structures are to remain on
the site, permanently, the owner
should furnish evidence that he will
adhere to a long-range agreement.
IX. IMPORTANT ASPECTS OF AN EROSION AND SEDIMENT CONTROL PLAN
A. No two erosion and sediment control plans will ever
be exactly alike. Each plan must be tailored to
the physical and climatic conditions at the site.
B. Most plans are somewhat similar, however, because
they contain the same basic features. Only the
more specific information differs.
1. A typical erosion and sediment control plan
is a drawing showing present and proposed
grading contours and elevations. The scale
should be one inch equals forty feet.
11-17
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2. The plan shows proposed construction, the
location of erosion control measures and
sediment control structures, typical or
detailed designs for various structures,
and general or specific notes regarding
the implementation of the plan.
3. The plan should include the owner's or
developer's certification and statement
that development and/or construction will
be done according to this plan of develop-
ment and erosion and sediment control.
4. Where local standards exist, the plan should
also be certified by the designer as having
been prepared in accordance with the
standards adopted by the approving agency.
5. Finally, the approving officer of the
district should affix his signature to
the plan.
6. Many erosion and sediment control plans
utilize certain standard symbols. You
should familiarize yourself with these
symbols, since they are used so widely.
The meanings of all these symbols are
explained in the legend,
7. Erosion and sediment control plans usually
have certain general notes containing general
sediment and erosion control requirements which
cannot be shown graphically on the plan.
11-18
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8. The sequence of implementation or "staging"
is also important and should be indicated
on the plan.
9. Certain specific notes concerning the approved
methods of soil stabilization should be
included on the plan.
a. The notes must include information on
temporary stabilization practices and
on permanent stabilization, both
vegetative and non-vegetative.
b. For vegetative soil stabilization, the
notes should cover seedbed preparation,
seeding procedures, and/or sodding
procedures.
c. Approved temporary non-vegetative
stabilization techniques, which include
mulching with various materials, and
chemical stabilization techniques, should
also be included in the notes.
d. In order to insure that adequate
stabilization is achieved, especially
with respect to vegetative techniques;
seeding dates, and application rates,
etcetera, should be included in the
soil stabilization notes.
10. Another major area which the erosion and
sediment control plan should cover is the
11-19
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maintenance of sediment control structures
Notes on this subject can be included in
the general notes or set out under a
separate heading. The portion of the
plan dealing with maintenance must cover
t
the cleaning of all structures and the
disposal of the sediment removed.
11. The plan must illustrate all structures
which call for formal designs. These
structures include sediment basins, ponds,
flumes, permanent diversion structures,
and so forth.
12. Temporary structures which do not require
formal designs, like diversion dikes and
sediment traps, are often not illustrated
on the plan. Instead, the plan includes
references to standard documents,
recognized by the approving agency,
which contain drawings and construction
requirements of the structures.
11-20
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Questions 1
Fill in the blanks.
1. Critical areas, where the potential for erosion is
high, include , , and
2. Most erosion and sediment problems can be avoided by
proper and .
3. In most areas of the country, most construction
activity takes place during the same seasons as
heavy occur.
4. One of the key strategies in erosion and sediment control
planning is to see to it that
is controlled on the site.
5. Another key strategy is to minimize .
6. There is a great deal we can do to control the
and of water, as it moves over the soil and
concentrates in waterways.
11-21
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Questions 2
True or false.
All landscapes impose the same restrictions on
the way in which they can be developed.
Before development commences, the developer must
determine the impact that erosion and sediment, produced
during and after the work, will have on his own site, and
on the areas lying downslope and downstream from the site.
The first step in an erosion and sediment control
plan is the design stage.
Measures designed for the management of stormwater
should be an integral part of the planning process, in any
sediment and erosion control plan.
The proper siting of structures will have no effect
on erosion and sediment damage.
When it is possible, grading should be minimized,
so as to reduce erosion.
11-22
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Questions 3
Circle the correct answer or answers.
1. The owner or site developer is responsible
a. for the preparation of the development plans only.
b. for the erosion and sediment control plans only.
c. for the preparation of both the development plans
and the erosion and sediment control plans.
2. During and after construction, the developer
a. must have the plans on hand, and must implement them.
b. can rely on the storm sewers, to handle runoff and
sedimentation.
c. has the responsibility to abate sediment pollution
and comply with local ordinances.
3. For a 10 acre site, the cost of setting up and following
an erosion and sediment control plan, may be $1500 or more
per acre; the cost of removing 200 cubic yards of sediment
from storm sewers alone, an amount that can easily be
generated by an acre during a year, will range from
a. $1200 to $3000
b. $12,000 to $30,000
c. $120,000 to $300,000
4. It is crucial to
a. make long-range studies of the landscape
b. prevent further development
c. allow developers to proceed as they see fit
11-23
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Questions 4
Write the letter that corresponds to the correct source of
the information described, in the blank provided.
a. County planning boards;
b. U.S. Geological Survey Offices;
c. Aerial maps and photographs furnished by the
Soil Conservation Service;
d. Highway offices;
e. Soil survey reports furnished by the Soil
Conservation Service;
f. Local planning and zoning agencies;
g. State Department of Natural Resources or other
agencies responsible for water pollution control.
Suitability of various soil types for locating
pipelines, roads, ponds, reservoirs, drainage systems,
and so forth.
Exact location of woodlands, wetlands, and other
critical or historical areas.
Important mineral deposits, critical underground
water supplies, location of rock outcrops, etc.
4. Location of present and future highways.
5. Soil engineering properties and areas having
drainage or flooding problems.
6. Local ordinances.
7. New regulations pertaining to erosion and sediment
control and updates on technical information.
11-24
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Write the letter that corresponds to the appropriate tool for
planning, in the blank provided.
a. Public agencies, such as the Soil and Water
Conservation District;
b. U.S.G.S. quadrangle map;
c. topographic or base map;
d. Professional consultant;
e. Enlarged aerial photograph or stereoscopic pairs
of air photos.
1. For site development (scale: 40 to 200 feet per
inch; contour interval: 2 to 5 feet).
2. For preliminary site evaluations.
3. For locating woodlands, wetlands, and other
critical features.
4. For consultation, during on-site studies.
5. For problems that are particularly difficult.
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Questions 5
Each of the following statements contains one error; write
the letter that corresponds to the incorrect word or phrase
in the blank provided.
1. One key requirement in the design of an erosion
and sediment control plan is: identify and protect
A
critical features. The physical factors of protective mulches,
A B
soils, landscape, drainageways, woodlands, and wetlands,
C D E F
taken together, should help determine the layout and design
of the development.
2. The second requirement is to reduce erosion and
A
runoff, in order to keep soil on the site. Expose the
A B
largest practical area, for the shortest time. Prompt
B C
revegetation is essential to reduce runoff and erosion.
C
Other techniques include surface roughening, diversion
D E
structures, and detention structures.
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3. The third requirement is preserve all woodland.
A
Sediment collection structures may be temporary or permanent,
B C
depending on the needs of a specific site. Sediment traps
will have to be cleaned out, from time to time during
D
construction.
4. The fourth requirement is stabilize the soil, as
A B
soon as possible after each grading step. With cut or fill
B
slopes, stabilization measures are normally applied in
20-foot vertical increments. During any type of grading
C
activity, the sooner an area is stabilized, the more
D
inspection and maintenance will be required.
D
5. The final requirement of any plan is inspection and
A
maintenance. The best-designed erosion and sediment control
A
plans will function adequately, if the owner or his repre-
sentative inspects and maintains all measures on a year-to-
B
year basis. Where sediment or stormwater management
B
structures are to remain on the site, permanently, the
developer should furnish evidence that he will adhere to
C
a long-range agreement:
C
6. A typical erosion and sediment control plan must
_
be tailored to the physical and climatic conditions at the
A A
site, and should include enlarged aerial photographs,
A B
proposed construction, the location of erosion control
C D
measures, and general and specific notes regarding the
D E
implementation of the plan.
E
11-27
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7. Specific notes included in the erosion and
sediment control plan contain information such as "the
A~
Order of Procedure," the temporary stabilization proced-
A B
ures, historical reports, and the maintenance of sediment
B C D
control structures.
D
Temporary structures which do not require formal
designs, like ponds, diversion dikes, and sediment traps,
A B C
are often not illustrated on the plan. Instead, the plans
include references to standard documents, which contain
drawings^ and construction requirements of the structures.
D
11-28
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Questions 6
Fill in the blanks.
1. The first step in the development of a site is the
After this step, the begins.
An erosion and sediment control plan is part of the
overall
The five most important requirements for an erosion and
sediment control plan are: 1. and
critical features; 2.
erosion and runoff; 3. sediment;
4. the soil; and 5.
inspection and maintenance of all control practices.
Each erosion and sediment control plan will contain a
drawing showing present and proposed
and elevations, the location of erosion
and sediment control , typical or detailed
for various structures, and other
general and specific regarding implementation
and maintenance.
11-29
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EROSION AND SEDIMENT CONTROL
WOODED - SITE DEVELOPMENT
WORKBOOK
-------
CONTENT
I GENERAL INTRODUCTION TO TREES
A. Trees as Living Things
B. Value
C. Parts of Tree
1. Roots
2. Trunks
3. Leaves
D. Types of Stands
E. Classification of Trees by Size
1. Seedlings
2. Saplings
3. Pole-sized Trees
4. Sawtimber
5. Veteran Trees
II PLANNING FOR PRESERVATION OF TREES
A. Important Questions to be Asked
B. Overall Plan Necessary
C. Selection of Individual Trees for Preservation
D. Selection of Lot
E. Roadways
F. Cleared Strips Around Buildings
G. Utility Spurs
12-1
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Ill CONSTRUCTION PRACTICES FOR PROTECTION OF TREES
A. Marking
B. Salvage
C. Stump Cutters
D. Pole-Size Stands
E. Traffic Control
F. Cut Slopes
G. Roadway Filling
H. Correct Operating Procedures
I. Trenching
J. Construction Activity
K. Soil Stockpiling
L. Fencing
M. Fill
N. Paving
O. Drainage
IV CORRECTIVE ACTION
A. Pruning
B. Treating Bark Damage
C. Compacted Soil
D. Fertilization
V ORGANIC LITTER
VI NECESSITY OF CORRECT PLANNING AND PROCEDURE
VII REVIEW QUIZ
12-2
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INTRODUCTION
A. Trees may appear not to be doing anything, but in
reality they are constantly active, taking in food
and water, giving up oxygen and taking in carbon dioxide
and moving nutrients from one part of their systems
to another.
B. Not only do they provide shade, they also protect
the soil from erosion, provide homes and food for
wildlife, reduce the runoff after heavy rainfall,
decrease the noise, slow down strong winds, and
add to the beauty of an area. They also enhance
our environment, by adding oxygen to the air,
while consuming carbon dioxide during the process
of growth.
C. Parts of Tree
1. Roots anchor the tree firmly in place. They
take in water and minerals from the soil,
through feeder roots, most of which are within
18 inches of the ground surface.
a. Feeder roots need oxygen to survive; they
can easily be suffocated by fill, compaction,
or asphalt.
b. The root system provides transportation routes
for water and plant food.
c. Roots store food manufactured by the tree.
2. The trunk is primarily composed of dead cells;
the trunk supports the tree and transports water.
12-3
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a. The inner bark, or "cambium," is composed
of living tissue and transports nutrients.
b. The cambium is especially fragile and can
easily be damaged by careless operation or
fire.
c. Girdling, the removal of a continuous strip
of bark all the way around the trunk, will
cause the tree to die.
d. Any damage to the outer bark allows disease-
causing organisms and destructive insects
to enter. This leads to rot and decay.
3. The leaves use the water taken in by the roots,
in combination with air and sunlight,to manu-
facture food for the entire tree.
a. If many branches are removed from a tree,
the entire tree may die, because it does
not have enough leaves to make food for
the whole tree.
D. A stand is a community of trees having the same age
and general appearance. Most construction occurs in
second-growth stands, which have grown up following
logging, fire, or some other large-scale removal.
E. Classification of Trees by Size
1. Seedlings are trees whose height does not exceed
four feet; while they are usually too small to
consider in planning development, they do serve
to hold the soil.
12-4
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2. Saplings are trees that are taller than four
feet and have diameters up to five inches.
Almost any of them may be selected for
preservation.
3. Pole-size trees have diameters ranging from
five to eleven inches.
a. Growing in stands, they usually have
small crowns and restricted root systems.
b. A tree's root system is roughly the same
size as its crown.
c. They are therefore liable to suffer "wind-
throw" when the protection of surrounding
trees is removed. "Wind throw" is the
damage that results when trees are tipped
or blown over by the wind.
d. Pole-size conifers are especially vulnerable
to wind throw.
4. Trees whose diameters measure between 11 and 16
inches are often called "small sawtimber."
Trees whose diameters exceed 16 inches are
called "large sawtimber."
a. When selecting these trees for preservation,
look for a well-developed crown, strong
crotches, and a trunk without rot or decay.
12-5
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5. Veteran trees are older trees that usually
exceed 24 inches in diameter. Their root
systems are large and cannot withstand the
stresses of construction activity as well
as younger trees can.
II PLANNING FOR PRESERVATION OF TREES
A. Questions to Consider in Planning Stage
1. Which trees do I want to save?
2. What will those trees need to survive?
3. How am I going to get equipment in and out of
the site?
4. Where am I going to put the earth I move?
5. Where am I going to store my supplies?
6. How can I protect the trees I want to save?
7. Are the trees I have selected going to be
suited to this site once construction has
been completed?
8. Will the trees be in harmony with the surrounding
site development?
B. The proper development of a wooded site depends
on the completion of an overall plan for the
preservation of the trees before clearing and
construction begins.
1. First, look over the entire area to find out
where the most valuable trees are growing and
where the most desirable building sites are
found.
12-6
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2. Locate floodplains and areas of highly
erodible soil or high groundwater.
3. Mark desirable tree stands and valuable
individual trees on the site map, for the
office personnel to assess in determining
the layout of the site.
4. Areas that are valuable for their beauty,
but undesirable for building or roadway
construction should be left as natural or
only partially improved open space.
C. Selection of Individual Trees for Preservation
1. When considering a tree for preservation,
keep in mind its age. If it is past its
prime, it may be unable to survive the
stresses imposed by construction.
2. Some trees, such as white oaks, beeches,
and maples, have longer life expectancies
and can withstand the stress of development
better than others, such as tulip poplars.
Short-lived trees such as willows are also
less desirable than longer-lived ones.
3. It may be better to save a smaller tree of a
desirable species than a nearby larger one;
not only will the younger tree live longer,
it can withstand the shock of construction
better, and if the older tree dies, the
landowner ends up paying the high cost of
having it removed.
12-7
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4. Examine the tree to see if its health is
satisfactory.
a. Look for scarring caused by fire or
lightning.
b. Make sure the tree is not growing from
an old stump. This may result in a weak trunk.
c. Inspect the tree for damage by insects
or diseases.
d. Check for rotted trunks or limbs.
e. Check the tree for stuctural defects.
f. Large trees with severe overhangs that
endanger life or property need pruning
or removal. If your knowledge of trees
is limited, hire an expert to evaluate
the trees.
D. The size of individual lots must be large enough for
the contractor to site the house properly and con-
duct operations efficiently. The smallest lot size
for wooded-site development should be one-half acre
or one-third acre at the very least, if you desire
to protect the trees adequately.
E. Roadways should be located so as to do the least
damage to the more valuable stands. Follow the
ground contour as much as possible, to minimize
cuts and fills.
12-8
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F. Provide a cleared strip of at least fifteen feet
around a structure, to prevent serious root damage
caused by excavation and to provide storage area
and space for working, separate from the wooded
area.
G. Position utility spurs to avoid damaging the roots
of trees.
1. Plan to place as many utilities in one trench
as possible, to minimize trenching.
Ill CONSTRUCTION PRACTICES FOR PROTECTION OF TREES
A. Marking
1. On clearings for roadways, mark the border
of the area to be cleared with flags, paint,
or fencing.
a. Use one color for trees to be removed and
another for trees to be saved.
b. Marking with paint is more permanent
and less subject to tampering.
c. Protect the trees outside the border
when you fell trees inside it.
d. Don't allow any traffic but essential
equipment in the protected areas.
B. Salvage
1. Large trees that are removed should be salvaged
for timber. Large limbs and smaller trunks can
be cut up for firewood and stacked on the site.
12-9
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2. Woodchippers are useful for processing
smaller trees and branches. The woodchips
are useful for erosion control or for
mulch for woody plants.
C. Stump cutting machines are best for removing
stumps, except where foundations are being
excavated.
1. Removing stumps by blasting or dozing
exposes more soil to erosion and does
more damage to adjacent trees. But for
roadways and building foundation areas,
the conventional techniques are still
necessary.
D. Pole-Size Stands
1. Because of their limited root systems,
the individual trees depend upon their
neighbors for protection.
2. If too many are removed, the remaining
trees are liable to topple during heavy
winds.
3. Because their bark is thin, the rapid
changes in temperature that result from
exposure to direct sunlight and wind may
cause serious bark damage.
4. Leave clumps of trees rather than individual
ones. As the trees mature they can be
thinned out, leaving the best ones room
to grow.
12-10
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E. Traffic Control
1. When grading begins, traffic control becomes
vital.
2. When access routes are necessary, locate
them so as to do the least amount of damage.
3. Careless operators damage or destroy many
trees. To avoid root and trunk damage,
construction traffic must be confined to
the right-of-way.
F. Cut Slopes
1. Along major routes where cut slopes are large,
provide a fifteen foot wide cleared zone in
back of the slope.
2. For less severe cut slopes in residential
areas, cribbings can help save valuable
trees.
G. Roadway Filling
1. Roadway gradings can alter the natural
moisture of the soil.
a. A cut slope placed too close to a
treeline may lower the moisture table.
A drop in the moisture table of only
six inches may kill trees.
b. Roots exposed on the slope can cause
"water piping." Water flows along the
roots, and removes soil.
-------
c. The roots that are not exposed take
up moisture that the grasses need to
grow.
d. Trees left too close to the edge of a
cut may shade the slope, thus preventing
a dense ground cover from developing.
This results in increased erosion.
e. Further erosion occurs when water drips
off the leaves or branches. To prevent
damaging sheet erosion, provide a fifteen
foot wide cleared zone in back of a large
cut, or cribbing along less severe cut
slopes.
G. Roadway Filling
1. Roadway filling can cause problems.
a. It may impound water, preventing feeder
roots from obtaining oxygen, thereby
causing damage to trees.
b. It also causes damage when it covers
the feeder roots of a tree.
2. Do not fill beneath the crown of a tree, as a
general rule.
3. In all cases, provide a minimum cleared zone
of fifteen feet, to prevent the fill from
covering the feeder roots.
12-12
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4. Good surface drainage at the base of the
fill will prevent excessive soil moisture.
H. Correct Operating Procedures
1. Operators should stay within the right-of-
way.
2. Watch where you swing backhoes and other
high-profile equipment.
3. Striking the bucket against a tree causes
severe damage to the bark.
I. Trenching
1. Try to keep trenching outside the crown of
the tree. A narrow trench that cuts the
feeder roots off from the rest of the tree
can destroy a tree as quickly as a fifty-foot
roadway cut.
2. Because the feeder roots are close to the
ground surface, a trench only eighteen
inches deep can inflict major damage.
3. When a utility spur leading to a home cannot
be relocated to avoid major root damage from
trenching, tunnel the utility under the feeder
roots of the tree. Special equipment for
doing this is available.
J. To avoid damage to the roots, keep all construction
activity outside the dripline of the crown (the
outward extent of the major portion of the feeder
roots).
12-13
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K. Soil Stockpiling
1. Soil not needed for foundation backfilling
should be removed from the site.
2. The remaining soil must be placed where
it will cause the least damage. Scattering
the soil in small piles, away from the trunks
of trees, minimizes damage.
L. To provide maximum protection, place fencing at
the dripline around the trees that you want to
preserve. This rule also applies to clumps of
trees.-
1. Fencing can be used to mark the limit of
clearing.
M. Fill
1. Grading and excavation should be kept outside
the dripline of any tree you wish to protect.
2. Most trees will tolerate up to six inches
of fill, but additional fill will cause
damage. Tulip poplars are particularly
susceptible.
3. When filling to a depth of more than six
inches is necessary, construct a tile and
porous stone well.
a. Place the tile and porous stone on the
ground out to the dripline.
12-14
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b. Cover with fill, leaving an open well
around the trunk. The well will allow
air to circulate to the root zone under
the fill.
N. Do not place paving underneath the crown of a
tree. Asphalt and concrete paving cut off the
supply of oxygen and moisture, resulting in
serious damage.
0. Failure to provide adequate surface and subsurface
drainage is also a cause of tree damage. Proper
grading practices help, but tile drains may also
be needed, if the problem is below the surface.
IV CORRECTIVE ACTION
A. When major root or bark damage occurs, remove some
foliage to reduce the demand for nutrients and
water. This operation is called "crown pruning."
1. In time, as the damage heals, more foliage
will grow back.
B. To treat bark damage, remove all loosened bark
from around the wound, provide drainage at the
base of the wound, and apply a proper wound
dressing to the damaged area.
C. If the soil has become compacted, aerate the
ground, by punching holes with an iron bar.
12-15
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1. Drive the bar a foot deep and then move
it back and forth until the surrounding
soil is loosened.
2. Repeat this procedure every eighteen
inches, until all the compacted soil
beneath the crown of the .tree has been
loosened.
D. Fertilization
1. Fertilization helps trees recover from the
stress imposed by construction activities.
2. To fertilize a tree, punch holes at regular
intervals into the ground inside the dripline
of the tree, then fill the holes with a
recommended fertilizer such as 16-8-8.
V ORGANIC LITTER
To preserve a natural setting of trees, make sure
the cover of organic litter or mulch is adequate.
It holds water, protects the roots, returns nutrients
to the soil, and reduces erosion.
VI NECESSITY OF CORRECT PLANNING AND PROCEDURE
A. Trees damaged by improper construction activity
die slowly. It may take three years or more
for a damaged tree to die.
B. Severe root damage caused by improper grading
can easily be hidden during final grading. The
12-16
-------
homeowner may not discover this damage for
several years.
C. To a homeowner, few things are more distressing
than paying thousands of dollars more for a
wooded lot, only to discover a few years later
that he will have to pay more money to have
these cherished trees removed, or risk major
property damage and, possibly, loss of life.
12-17
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Questions 1
Circle the correct answer or answers.
1. Trees . . .
a. take in food and water.
b. exchange nitrogen for helium.
c. move nutrients from one part of their system to another.
2. Trees . . .
a. cause destructive erosion.
b. provide homes and food for wildlife.
c. reduce the runoff after heavy rainfall.
d. decrease surface water infiltration.
e. slow down winds.
f. add to the beauty of an area.
3. Trees . . .
a. enhance our environment.
b. add oxygen to the air.
c. consume carbon monoxide.
4. The root system . . .
a. anchors the tree firmly in place.
b. pumps water and minerals from the tree into the soil.
c. is impossible to suffocate.
d. transports vital materials from the feeder roots to
other parts of the tree.
e. stores food manufactured by the tree for later use.
12-18
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5. T or F Trunks have little to do with the well-being
of trees.
6. The wood inside the trunk. . .
a. supports the tree.
b." transports mostly minerals.
7. The inner bark, or "cambium,"
a. transports nutrients.
b. is hard to damage.
8. T or F If you remove a continuous strip of bark all the
way around the trunk the tree will continue its formal development.
9- Damage to the cambium
a. allows diseases and pests to enter.
b. leads to rot .and decay.
10. T or F iT-e leaves consume food manufactured elsewhere in the tree.
Complete the following sentences by filling in the blanks:
1. Most construction occurs in stands.
2. are the youngest trees (less than 4 feet tall).
3. , which are taller than four feet, have diameters
up to five inches. Almost any of them may be selected for preservation,
4. trees have diameters ranging from five to
eleven inches. As a result of their small root systems, these trees
often suffer .
5. Trees whose diameters measure between 11 and 16 inches are called
6. Trees whose diameters measure between 16 and 24 inches are called
7. When selecting mature trees for preservation, look for a well developed
, strong __, and a without rot
or decay.
8. trees usually exceed 24 inches in diameter. They
are often over-mature.
12-19
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Questions 2
Mark each statement True or False.
1. Before beginning a project you should decide which trees
you want to save.
2. Each different piece of equipment should use its own
access road.
3. You should decide ahead of time where to put earth and
where to store supplies.
4. The proper development of a forested site depends on
waiting until construction begins, to see what steps
should be taken.
5. First the planner should look over the entire area, to
find out where the most valuable trees are growing and
where the most desirable trees are found.
6. Areas that are valuable for their natural beauty, but
undesirable for building or roadway construction, should
be left as natural or only partially improved open space.
7. Trees should be left to provide shade, whether or not
they will survive construction.
8. White oaks, beeches, and maples adapt poorly to the
stress of development.
9. Tulip-poplars adapt poorly to the stress of development.
10. In selecting a tree for preservation, a planner should
inspect it for damage by insects or diseases, should
check for rotted limbs or trunks, and should look for
structural defects.
11. The smallest lot size for wooded site development is one
acre.
12. It is better to rely on deep cuts and long fills than to
follow the ground contour as much as possible.
13. Providing a cleared strip of at least fifteen feet around
a structure will help prevent serious root damage caused
by excavating the foundation.
14. The positioning of utility spurs does not effect trees.
12-20
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Questions 3
Circle the correct answer or answers.
1. If you're going to clear woods for roadways, mark
the border of the area to be cleared
a. with flags, paint, or fencing.
b. with lime.
2. When you fell trees inside the border, be careful
to protect the. trees
a. inside the border.
b. outside the border.
c. inside and outside the border.
3. When you clear selected trees mark
a. all the trees with the same color
b. the trees to be saved with one color, and the
the trees to be cleared with another color.
4. Large trees that are removed should be salvaged
a. for timber.
b. for woodchips.
5. Stump cutting machines are best for removing stumps
a. where foundations are being excavated.
b. where roadways will be located.
c. except for roadways and building foundation areas,
6. T or F Pole-size trees should be left as individuals.
12-21
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7. Access routes
a. can be left to the discretion of the operators.
b. should be located so as to do the least amount
of damage.
c. can be ignored, if the operator wants to drive
through a wooded area you hope to protect.
8. T or F Along major routes where cut slopes are larae, provide
a fifteen-foot wide cleared zone in back of the cut.
9. Roadway filling
a. cannot harm the feeder roots of a tree.
b. should not be allowed beneath the crown of a
tree.
1O. In all cases where filling is being done provide
a. a minimum clear zone of fifteen feet to prevent
the fill from covering the feeder roots.
b. underground drainage tiles
12-22
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Questions 4
Mark each statement true or false.
1. Operators should stay within the right-
of-way.
2. Striking the bucket against the tree
causes severe damage to the bark.
3. You should try to keep trenching outside
the crown of the tree.
4. When a utility spur leading to a home
cannot be relocated to avoid major root
damage from trenching, you should tunnel
the utility under the feeder roots of the
tree.
5. All construction activity should be kept
outside the dripline of the crown.
6. Soil that is needed on the site should be
placed where it will cause the least damage,
preferably scattered in small piles.
7. To provide maximum protection, place fencing
at the dripline around the trees that you want
to preserve.
8. Grading and excavation should be kept outside
the dripline of any tree you wish to protect.
9. When filling to a depth of more than six
inches is necessary, construct a tile and
porous stone well.
12-23
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10. Do not place paving underneath the
crown of a tree.
11. Tile drainage may be necessary, where
there is a subsurface drainage problem
resulting in inadequate surface and
subsurface drainage.
Complete the following sentences by filling in the blanks:
1. When major root or bark damage occurs, remove some
to reduce the demand for nutrients and water,
2. To treat bark damage, remove all loosened
from around the wound, provide at the base
of the wound, and apply a proper
to the damaged area.
3. If the soil becomes compacted, aerate the ground by
with an iron bar.
Drive the bar a foot deep and then move it
back and forth, until the surrounding soil is .
Repeat this procedure every inches, until
all the compacted soil beneath the crown of the tree
has been loosened.
4. is another maintenance procedure that helps
trees recover from the stress imposed by construction
activities. To a tree, punch holes at
regular intervals in the ground inside the
of the tree. Then fill the holes with a recommended
5. To preserve a natural setting of trees, make sure the
cover of is adequate.
6. Trees damaged by improper construction activity usually die
. (rapidly? slowly?)
12-24
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Questions 5
Each of the following sentences contains one error. Write
the letter in the blank that corresponds to the part of
the statement that is incorrect.
The roots absorb minerals and water from the soil,
A
transport these nutrients to the trunk, take in carbon
B C
dioxide from the air, and release oxygen, and store
C D
important materials.
D
The trunk supports the crown, transports material
A B
between the roots and the crown, and manufactures food
B C
for the whole tree.
3. The cambium is difficult to damage, and it does
A B
most of the work of transporting material in the trunk.
4. The inner wood moves upward as the tree grows,
A
supports the crown, and transports water.
B C
5. The leaves manufacture food for the whole tree and
A
contain little or no living tissue.
B
6. Seedlings are up to four feet high and have no
.A B
effect on the amount of erosion.
B
12-25
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7. Saplings are smaller than seedlings and
A
have diameters less than 5".
B
8. Pole-size trees have diameters greater than 5"
A
but less than 11"; during clearing, they should be left
B C
as individuals.
Sawtimber includes trees greater than 11";
A
sawtimber cannot withstand the stress of development.
B
1O. Veteran trees are insensitive to the stress of
A
development; their trunks usually exceed 24" in diameter.
A B
11. The proper development of a forested site depends
mainly on seasonal conditions but also on the completion
A B
of an adequate overall plan, before clearing and construction
B C
begins.
C
12. First, look over the entire area to see whether
A B
soil stabilization will be necessary, and to locate the
B C
most valuable and desirable trees.
13. Areas that are valuable for their natural beauty,
but undesirable for building and roadway construction
should be cleared or left as natural or only partially
A B
improved open space.
B
14. When considering a tree for preservation, consider
its age, species, health, need for fertilizer, size, and
~A~~ B C D E
structural defects, if any.
F
12-26
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15. Trees that adapt well to the stress of construction
include white oaks, tulip-poplars, maples, and beeches.
ABC D
16. Home lots in wooded areas should be at least
one-half acre, or one-eighth acre, at the very least.
A B
17. After construction begins locate the roadways,
A B
utilities, homesites, and other features so as to do
C D
the least damage to the more valuable stands.
E
Mark each statement true or false.
1. Before clearing wooded areas, trees should
be marked clearly to distinguish between
valuable trees for preservation, and
undesirable trees, for removal.
2. Trees which have been removed should be
promptly burned.
3. The stump-cutter should be used for removing
stumps only as a last resort.
4. Badly damaged or diseased trees should be
left alone .
Generally, trees located within fifteen feet
of a structure should be removed.
Fencing around the dripline of trees helps
protect them from construction activities.
Pruning, root aeration, treating wounds, and,
fertilization, do little to help a tree recover
from injuries or the stresses imposed by con-
struction activities.
When trees are injured beyond repair, you
should remove them promptly , rather than
hide the damage and leave them to die later.
12-27
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EROSION AND SEDIMENT CONTROL
FOREMAN - INSPECTOR
RESPONSIBILITIES
WORKBOOK
-------
CONTENT
I. ROLES OF THE FOREMAN AND INSPECTOR
A. The Foreman
B. The Inspector
II. FOREMAN-INSPECTOR TEAM
A. Responsibilities
1. General
2. Preparation
(a) Know the law
(b) Have working knowledge of current
practices
(c) Know the plans
(d) Organize your activities
3. On-site evaluation and control
(a) Checking the implementation of plans
(b) Checking the performance of plans
4. Follow-up Action
5. Working with people
III. SOCIAL CONTROL OR ENFORCEMENT
A. Enforce
B. Implement
IV. PUBLIC CONTRACT
V. REVIEW
13-1
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I. ROLES OF THE FOREMAN AND INSPECTOR
A. The Foreman
1. Is a key man in the effective control of
erosion and sediment.
2. Serves "as a first line of defense".
3. Has the best working knowledge of the site.
4. Must assume much of the responsibility for
ensuring that the public's goal of control-
ling erosion and sediment is accomplished.
B, The Inspector
1. Serves as a "back-up or reinforcement".
2. Has a better overall view of erosion and
sediment control.
3. Is in the best position to objectively
evaluate the total performance of the ero-
sion and sediment control efforts on a site,
4. Must share the responsibility for ensuring
that the public's goal of controlling ero-
sion and sediment is accomplished.
13-2
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II. FOREMAN-INSPECTOR TEAM - the role of the foreman and
inspector cannot be viewed as separate.
A. Responsibilities
1. General - Field Implementation
a. Responsible for the "on-site" phase of
the erosion and sediment control program.
b. Responsible for making the vital link
between successful planning and effective
on-site control of erosion and sediment.
2. Preparation
a. Know the law.
(1) Specialists must have a clear under-
standing of the laws, ordinances,
regulations, and procedures affect-
ing their activities.
(2) Effective field implementation is
directly related to the knowledge of
the provisions of the laws and regu-
lations.
b. Have working knowledge of current practices
(1) needed for proper implementation of
sediment control plans.
(2) needed to solve on-site problems.
13-3
-------
c . Know the plans.
(1) Foreman and inspector must be
thoroughly familiar with the ac-
tual sediment control plans and
specifications for a project.
(2) Pay attention to the type, sched-
uling, staging and location of
practices detailed in the plan.
(3) V7hen possible, schedule an on-
site meeting to review the plans
in order to establish open com-
munication and prevent needless
misunderstanding.
d. Organize your activities.
(1) Control practices require period-
ic checking and maintenance.
(2) The foreman must plan and schedule
time for sediment and erosion con-
trol.
(3) The inspector must determine how
many inspections he can make in
an average day, and relate this
figure to his total workload to es-
tablish a regular return interval.
He may also plan for unexpected
visits to vary his routine.
13-4
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3. On-site evaluation and control
a. Checking the implementation of plans.
(1) Determine if the approved erosion
and sediment control plans and per-
mits are being properly carried out.
(2) Should be a joint operation.
(3) Check the entire site.
(4) Visualize the measures shown on the
plans.
(a) Is the scheduling and staging
of the plans being followed?
(b) Are the practices shown on the
plan installed as per design
and located properly?
(c) Are the practices shown on the
plan being adequately maintained?
b. Checking the performance of plans.
(1) During and after rainstorms the fore-
man and inspector must check to see
if there is any significant damage
occuring off-site.
(2) If obvious deposits of sediment are
visible off-site, significant damage
is occuring and additional or im-
proved control is necessary.
13-5
-------
(3) Watch the following activities:
(a) utility construction
(b) traffic control and storage
areas
• (c) changes in the staging of a
project
4. Follow-up action
a. Document on standard report forms the
findings of inspections conducted.
b. Decisions should be made and recorded
regarding action to be taken to cor-
rect problems.
(1) Minor modifications and corrections
can be made directly £>Y the field
specialists.
(2) Major modifications or corrections
will usually require additional re-
view by the consultant for the pro-
ject and the inspector's supervisor.
c. Sometimes official enforcement action is
the only way of obtaining compliance with
approved plans and permits.
13-6
-------
5. Working with people
a. Controlling people - learning how to
communicate with, educate, and gain
the cooperation of people.
b. The foreman needs to inform and train
his men in order to achieve effective
erosion control.
c. The inspector needs to make sure that
the foreman adequately understands
and carries out an effective sediment
control effort.
d. Both field specialists are really
"amateur psychologists".
III. SOCIAL CONTROL OR ENFORCEMENT is a vital activity
needed for the health, safety, and welfare of the
people. It is made up of two ideas:
A. Enforce
1. Refers to laws.
2. Implies the exercise of police power or
force.
B. Implement
1. Action necessary to bring into effect some
agreed-on plan or policy.
2. This idea is often ignored.
13-7
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IV. PUBLIC CONTACT - putting into effect what everyone
agreed to do in the first place.
The foreman and inspector are "regulators", they
have taken on the responsibility of making sure
that the goals and objectives are met in the field,
13-8
-------
QUESTIONS 1
True or False
_1. The inspector serves "as a first line of defense".
2. The foreman is a key man in the effective control
of erosion and sediment.
3. The inspector has the best working knowledge of a
site.
4. The inspector is in the best position to objective-
ly evaluate the total performance of the erosion
and sediment control efforts on a site.
5. The foreman has a better overall view of erosion
and sediment control.
6. The foreman serves as "a back up or reinforcement".
13-9
-------
Multiple Choice
1. The effectiveness of an erosion and sediment control
program depends upon:
a. planners.
b. consultants and technical specialists.
c. citizens and elected officials.
d. field specialists.
e. all of the above.
The responsibility for preparation includes:
a. knowing the law.
b. having working knowledge of current practices.
c. knowing the plans.
d. organizing your activities.
3. Knowing the law means that a field specialist must
have a clear understanding of affecting
their activities.
a. laws
b. ordinances
c. regulations
d. procedures
e. all of the above
Having a working knowledge of current practices is
needed:
a. for proper implementation of sediment control
plans.
b. to solve on-site problems.
c. both a and b.
d. none of the above.
anAwe.fi (A }
13-10
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QUESTIONS 3
Multiple Choice
1. Checking the implementation of plans includes:
a. checking the entire site.
b. visualizing the'measures shown on the plans.
c. determining if the approved plans and permits
are being properly carried out.
d. foreman and inspector working together.
2. For effective erosion and sediment control, practices
must be installed:
a. any time.
b. at the proper time.
c. at the beginning.
3 . In checking the performance of plans one should
watch:
a. utility construction.
b. traffic control.
c. changes in staging.
13-11
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QUESTIONS 4
Fill in the blanks
1. modifications and corrections can
usually be made directly by the field specialists.
2. Sometimes official e action is the only
way of obtaining compliance with approved plans and
permits.
3. By people, we really mean learning
how to c with, e , and gain
the cooperation of people.
4. The word refers to laws and implies
the exercise of police power or force.
5. By implementing, we mean action to bring into effect
some agreed upon .
6. A public c involves putting into effect
what everyone agreed to do in the first place.
13-12
-------
Fill in the blanks
1. The serves "as the first line of defense".
2. The serves "as the back up of reinforce-
ment" .
3. The has a better overall view of the prob-
lems and conditions in the area.
4. The has the best working knowledge of a
site.
5. The responsibility of preparation includes:
a. Know
b. Have
c. Know
d. Organize
6. The responsibility of on-site evaluation includes:
a. Checking the i of plans.
b. Checking the 2 °f plans.
7. When checking performance one should watch out for the
following activities:
a. construction.
b. control.
c. Changes in .
13-13
-------
8. M modification will usually require
additional review by the consultant for the project
and the inspector's supervisor.
9. Sometimes official e action is the only
way of obtaining compliance with approved plans and
permits.
10. By people, we really mean learning
how to communicate with, , and gain
the c of people.
11. In order to achieve effective erosion control, the fore-
man needs to i • and t his
men, and the inspector needs to make sure the
understands and carries out an effective sediment control
effort.
12. The word enforce refers to 1 and implies
the exercise of p_ p_ or
force.
13. By i we mean action necessary to bring into
effect some agreed upon p .
13-14
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO.
EPA-6QQ/8-76-Q01b
2.
4. TITLE AND SUBTITLE
Erosion and Sediment Control
Audiovisual Training Program Instructor's
Workbook
6. PERFORMING ORGANIZATION CODE
3. RECIPIENT'S ACCESSION1 NO.
5. REPORT DATE
June 1976
7. AUTHOR(S)
Thomas R. Mills; Michael A. Nawrocki; Gregg R.
Squire; Homer T. Hopkins; Michael L. Clar
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Hittman Associates, Inc.
Environmental & Geosciences Department
9190 Red Branch Road
Columbia, Maryland 21045
10. PROGRAM ELEMENT NO.
1BC611 PEMP 03
11. CONTRACT/GRANT NO.
S-800854
Project No. 5800854
12. SPONSORING AGENCY MAME AND ADDRESS
and
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
Water Resources.Administration, State of
Maryland, Annapolis, Maryland 21401
13. TYPE OF REPORT AND PERIOD COVERED
Final Report
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
Prepared in cooperation with the Water Resources Administration,
State of Maryland
16. ABSTRACT & series' of technical presentations and a certification plan foi
erosion and sediment control specialists are presented. Thirteen
lessons complete with visual aids, student handouts and audiovisual
handouts consisting of slides, vidiotape and tape narration, workbooks
and instructor's manuals are developed. These materials are designed to
provide an effective education program for qualifying construction per-
sonnel and others to pass a certification examination. The list of the
lessons is as follows:
1. Goals, Objectives and Principles of Erosion and Sediment Control
2. Soils
3. Rainfall-Runoff Relationships
4 . Erosion and Sedimentation
5. Plant Materials
6. Control of Runoff During Construction
7. Vegetative Soil Stabilization
8. Stream Erosion Control
y. Temporary Soil Stabilization
10. Control of Sediment Generated on Construction Sites
11. Erosion and Sediment Control Planning
12. Wooded Site Development
13. Foreman-Inspector Responsibilities
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Erosion Control
Sediment Control
Education
Sediment Control
Construction Related
Erosion
Technical Presen-
tation
05 I
13 B
B. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO OF PAGES
85
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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