EPA R2-72-015
August 1972
Environmental Protection Technology Series
Guidelines for Erosion
and Sediment Control Planning
and Implementation
.
SEZ
01
CD
Office of Research and Monitoring
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, eguipment and
methodology to repair or prevent environmental
degradation from point and non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards.
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EPA-R2-72-015
August 1972
GUIDELINES FOR EROSION AND SEDIMENT CONTROL
PLANNING AND IMPLEMENTATION
The Department of Water Resources, State of Maryland
Annapolis, Maryland
and
Burton C. Becker
Thomas R. Mills
Hittman Associates, Inc.
9190 Red Branch Road
Columbia, Maryland 210^5
Project 15030 FMZ
Prepared for
OFFICE OF RESEARCH AND MONITORING
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
For sale by the Superintendent 9! Documents, U.S. Qovernment Printing Office
Washington, D.C. 20402 - Price $1.75
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EPA Review Notice
This report.has been reviewed by the Environmental Protection
Agency and approved for publication. Approval does not signify that
the contents necessarily reflect the views and policies of the
Environmental Protection Agency, nor does mention of trade names
or commercial products constitute endorsement or recommendation
for use.
11
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ABSTRACT
"Guidelines for Erosion and Sediment Control Planning and Implementa-
tion" is the first of three major documents being generated as part of
the "Joint Construction Sediment Control Project' being conducted in
Columbia, Maryland. This project is being operated by the Maryland
Department of Water Resources under an Environmental Protection
Agency grant.
The principal purpose of the "Guidelines" is to help those responsible for,
or engaged in, urban construction prevent the uncontrolled movement of
soil and the subsequent damage it causes. The "Guidelines" presents a
comprehensive approach to the problem of erosion and sediment control
from beginning of project planning to completion of construction. It
provides:
(1) A description of how a preliminary site evaluation
determines what potential sediment and erosion
control problems exist at a site being considered
for development
(2) Guidance for the planning of an effective sediment
and erosion control plan
(3) Procedures for the implementation of that plan
during operations
Technical information on 42 sediment and erosion control products,
practices, and techniques is contained in four appendices. In addition,
a cross-index and a glossary of technical terms used in the document
are provided.
The "Guidelines" is designed and intended for use by both technical and
lay personnel.
111
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CONTENTS
Section
I Introduction 1
II Preliminary Site Evaluation 5
A General 5
B Maps and Airphotos 5
C Soils and Geological Information 6
D Technical Assistance 8
E Evaluation of Prime Physical Features 9
1 Land Type 9
2 Soil and Rock 13
3 Streams 13
4 Floodplains 16
5 Impoundments 17
6 Groundwater Conditions 17
7 Vegetative Cover 17
III Planning 19
A General 19
B Preliminary Site Investigation 19
1 Delineation of Critical and Prime Physical
Features 19
2 Detailed Topographic Mapping 20
C Preliminary Design 20
D Subsurface Investigation 21
1 Vegetative Stability 21
2 Soil Erodibility 23
3 Soil Chemistry 23
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CONTENTS
(Continued)
Section Page
4 Groundwater 23
5 Topsoil 24
E Final Design 24
1 Stabilization of Major Waterways 24
2 Stabilization of Minor Waterways 32
3 Stabilization of Soil Slopes 35
F Formulation of Erosion and Sediment Control
Plan 41
1 Clearing and Grading Schedule 42
2 Location, Construction, and Maintenance
of Sediment Retention Structures 44
3 Traffic Control 44
4 Stream Erosion 45
5 Planting Schedule 45
6 Grading Delays 45
IV Operations 47
A General 47
B Roadway Construction .„
C Underground Utility Construction 4Q
D Building Construction 5
V Maintenance 57
VI Acknowledgment 5g
VII References 6l
VIII Glossary 63
VI
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CONTENTS
(Continued)
Section
IX Appendices 77
A Chemical Soil Stabilizers, Mulches, and
Mulch Tacks 78
B Erosion and Sediment Control Structures 97
C Fiber Mulches, Mulch Blankets, and Netting 163
D Special Erosion and Sediment Control Practices 193
VII
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FIGURES
PAGE
1 BARREN AREA 9
2 AGRICULTURAL AREA 10
3 WOODLAND AREA 11
4 WOODLAND AREA - MATURE STAND 11
5 WOODLAND AREA - POLE STAND 12
6 WOODLAND AREA MIXED STAND 12
7 CHANNEL LINED WITH HAND PLACED ROCK 14
8 FLOODPLAIN IN DEVELOPED AREA 16
9 GROUNDWATER TABLE EXPOSED IN A
BASEMENT EXCAVATION 18
10 WELL ESTABLISHED VEGETATION IN A MINOR
DRAINAGE WAY 18
11 NATURAL FILTER STRIP SEPARATING BARE
SOIL (FOREGROUND) FROM A STREAM CHANNEL
(DARK VEGETATION IN MIDDLEGROUND) 21
12 VEGETATIVE STREAMBANK STABILIZATION 26
13 CHECK DAM WITH ENERGY DISSIPATOR 28
14 COMBINATION OF CHECK DAMS AND LINED
CHANNEL 28
15 CHECK DAMS (WEIRS) CONSTRUCTED OF WOOD 29
16 SACKED CONCRETE REVETMENT 3Q
17 JUTE NETTING BEING USED IN WATERWAY
STABILIZATION 34
18 DIVERSIONS BEING USED TO CONTROL
DOWNSLOPE RUNOFF 36
19 CHEMICAL MULCH TACK BEING APPLIED 4o
Vlll
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FIGURES
(Continued)
PAGE
20 FILTER BERM 42
21 EXAMPLE OF A SEDIMENT AND EROSION
CONTROL PLAN 43
22 EROSION ALONG AN IMPROPERLY BACKFILLED
UTILITY TRENCH 49
23 FIREWOOD PRODUCED DURING CLEARING
OPERATIONS 52
24 USE OF WOODCHIPS AS AN INTERIM EROSION
CONTROL PRACTICE ON A HOMESITE 52
25 SELECTIVE STOCKPILING TO PROTECT TREES 53
26 STOCKPILE WITH A NATURAL FILTER STRIP
LOCATED DOWNSLOPE 54
27 EROSION AT AN UNPROTECTED DRIPLINE 56
28 DRIPLINE PROTECTION WITH A FIBER GLASS
BLANKET 56
A 1 CHEMICAL SOIL STABILIZER BEING APPLIED TO
AN AREA THAT WILL BE SEEDED AT A LATER
DATE 79
A-2 CHEMICAL MULCH TACK BEING APPLIED TO
STRAW MULCH 79
A-3 CHEMICAL MULCH BEING APPLIED IN A
HYDROSEEDER SLURRY WITH LIME, FERTILIZER,
AND SEED 80
B-l CHECK DAMS CONSTRUCTED OF GABIONS AND
ROCK RIPRAP 99
B-2 ROCK AND WOOD CHECK DAM 99
B-3 CHUTE/FLUME 102
B-4 FLUME WITH ENERGY DISSIPATORS 103
IX
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FIGURES
(Continued)
PAGE
B-5 CONCRETE CHUTE 103
B-6 CONCRETE CHUTE 104
B-7 DIVERSION DIKE 106
B-8 DIVERSION DIKE AT TOP OF SLOPE 107
B-9 DIVERSION DIKE CONSTRUCTED BY DOZER
MOVING SOIL UPSLOPE AND DUMPING AT TOP
OF SLOPE 107
B-10 DIVERSION ON A STABILIZED SLOPE 108
B-ll EROSION CHECK 111
B-12 FIBER GLASS EROSION CHECK IN TRENCH -
AWAITING BACKFILL 112
B-13 FIBER GLASS EROSION CHECK AND WELL
ESTABLISHED VEGETATION 112
B-14 FAERIFORM® MAT IN PLACE, AWAITING FILLING 116
B-15 COMPLETED FABRIFORM® (FILTERPOINT)
STRUCTURE 116
B-16 FABRIFORM® CHANNEL LINING BEING FILLED 117
B-17 FABRIFORM® CHANNEL LINING BEING FILLED
NOTE UNINTERRUPTED STREAM FLOW 117
B-18 FABRIFORM® (UNIFORM CROSS SECTION)
CHECK DAM 118
B-19 FILTER BERM 12Q
B-20 FILTER BERM - INSTALLED 121
B-21 FILTER BERM - INSTALLED m
B-22 FILTER INLET 124
B-23 FILTER INLET - INSTALLED 124
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FIGURES
(Continued)
B-24 FILTER INLETS - INSTALLED 125
B-25 FILTER INLET REQUIRING MAINTENANCE 125
B-26 FILTER INLET 126
B-27 FILTER INLET - INSTALLED 126
B-28 FLEXIBLE DOWNDRAIN 129
B-29 FLEXIBLE DOWNDRAIN - ISOMETRIC 130
B-30 FLEXIBLE DOWNDRAIN - INSTALLED 130
B-31 FLEXIBLE DOWNDRAIN INLET STRUCTURE 131
B-32 GABIONS - CHANNEL BANK PROTECTION 133
B-33 GABIONS - CHANNEL BANK PROTECTION 133
B-34 GABIONS - PROTECTION AT STREAM BEND 134
B-35 GABIONS CHANNEL LINING, CHECK DAM
AND BANK PROTECTION 134
B-36 INTERCEPTOR DIKE 137
B-37 INTERCEPTOR DIKE INSTALLED AND
OUTLETTING TO STORM SEWER INLETS 138
B-38 INTERCEPTOR DIKE - INSTALLED 138
B-39 LEVEL SPREADER 141
B-40 SANDBAGS AT SITE FOR CONSTRUCTION OF
SEDIMENT CONTROL STRUCTURE 143
B-41 SANDBAG STRUCTURE IN PLACE 143
B-42 SECTIONAL DOWNDRAIN 146
B-43 SECTIONAL DOWNDRAIN USED AS A DITCH LINER 146
B-44 SECTIONAL DOWNDRAIN 147
B-45 SEDIMENT RETENTION STRUCTURE - SMALL,
LESS THAN 1/4-ACRE 155
XI
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FIGURES
(Continued)
PAGE
B-46 SEDIMENT RETENTION STRUCTURE - LARGE
4 ACRES. WILL BE CONVERTED FOR
RECREATIONAL USE AFTER DEVELOPMENT
IS COMPLETE 156
B-47 SEDIMENT RETENTION STRUCTURE - 1 ACRE 156
B-48 SEDIMENT RETENTION STRUCTURE.
MAINTENANCE PAST DUE 157
B-49 SEDIMENT RETENTION STRUCTURE NOW
REQUIRING MAINTENANCE (CLEANOUT) 157
B-50 STRAW BALE STRUCTURE AT STORM DRAIN INLET 160
B-51 STRAW BALE STRUCTURE AT SEDIMENT
RETENTION STRUCTURE (TIDAL) 160
B-52 STRAW BALE STRUCTURE ON PROPERTY LINE 161
B-53 STRAW BALE STRUCTURE AT STORM DRAIN
INLET 161
C-l EXCELSIOR BLANKET AND STAPLE 165
C-2 DRIVING STAPLE TO ANCHOR EXCELSIOR
BLANKET 166
C-3 FIBER GLASS MAT AT CULVERT INVERT 168
C-4 GLASSROOT^ APPLICATION 170
C-5 GLASS ROOT155 IN PLACE 170
C-6 GLASSROOT^ IN PLACE. VEGETATION STARTING 171
C-7 JUTE NETTING BEING INSTALLED
C-8 JUTE NETTING - CLOSE UP 174
C-9 JUTE NETTING OVER STRAW MULCH IN A
DRAINAGE WAY 175
C-10 MULCH BLANKET BEING INSTALLED 177
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FIGURES
(Continued)
PAGE
C-ll MULCH BLANKET BEING STAPLED 178
C-12 PLASTIC NET OVER FIBER GLASS ROVING -
CLOSEUP 180
C-13 PLASTIC NET (ON ROLL) READY FOR
INSTALLATION IN CRITICAL AREA 181
C-14 STRAW MULCH BEING APPLIED BY MULCH BLOWER 184
C-15 LARGE STRAW MULCHING OPERATION 184
C-16 ASPHALT BEING USED TO TACK STRAW MULCH 185
C-17 WOODCHIPS - APPLICATION RATE IS 4 CUBIC
FEET PER 100 SQUARE FEET OF AREA 187
C-18 WALKWAY OF WOODCHIPS 188
C-19 SPREADING WOODCHIPS ON HOME SITE 188
C-20 WOODFIBER (SHORT FIBER) BEING APPLIED
IN HYDROSEEDER SLURRY 191
C-21 WOODFIBER MULCH IN PLACE (CLOSEUP) 192
D-l WATER BEING PUMPED FROM AN EXCAVATION
AND BEING DISCHARGED ONTO A SPOIL PILE 197
D-2 SAME AREA AS FIGURE D-l. PUMPED WATER
SHOULD BE DISCHARGED TO COMPLETED STORM
DRAIN 197
D-3 PUMPED WATER BEING DISCHARGED TO STABLE
AREA (SURFACED STREET) RATHER THAN TO
BARE SOIL 198
D-4 SCARIFICATION UP AND DOWN SLOPE AIDS
EROSION 200
D-5 SCARIFICATION ACROSS SLOPE AIDS EROSION
CONTROL 201
Xlll
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FIGURES
(Continued)
_PAGE_
D-6 SERRATED CUT A TYPE OF ROUGHENED
SLOPE 201
D-7 SCARIFICATION ON SLOPE BEHIND
HOMESITES 202
D-8 STUMP CUTTER 204
D-9 STUMP CUTTER REMOVING STUMP 204
D-10 STUMP PARTIALLY REMOVED BY STUMP
CUTTER 205
D-ll RILLS IN EQUIPMENT TRACKS 208
D-12 ROAD COMPLETELY CLOSED BY SANITARY
SEWER CONSTRUCTION 208
D-13 TWO ROUTES (ONE IS CONVENIENCE ROUTE)
TO SAME LOCATION 209
D-14 AREA COMPLETELY DENUDED BY EQUIPMENT
TRAVEL 209
D-15 "CONVENIENCE" ROUTE THROUGH A STAND
OF TREES MARKED FOR PRESERVATION 210
D-16 INCORRECT FENCING FOR TREE PROTECTION 213
D-17 CORRECT FENCING FOR TREE PROTECTION 213
D-18 CORRECT FENCING FOR TREE PROTECTION 214
D-19 TREE PROTECTION - SELECTIVE STOCKPILING
SOIL FROM BASEMENT EXCAVATION 214
D-20 TREE PROTECTION TILE AND GRAVEL WILL
ALLOW AIR CIRCULATION TO ROOT ZONE UNDER
A FILL 215
D-21 TREE PROTECTION - TUNNELING 21g
D-22 SOD FILTER STRIP ON STOCKPILE FOR WINTER
PROTECTION 2lg
xiv
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FIGURES
(Continued)
PAGE
D-23 SOD FILTER STRIP AND STRAW BALES ON
STOCKPILE FOR WINTER PROTECTION 219
D-24 SOD FILTER STRIP AT STORM DRAIN INLET 220
D-25 SEDIMENT DEPOSITION AT SOD FILTER STRIP 220
D-26 TREES MARKED FOR PRESERVATION 224
D-27 TAKING DOWN A TREE AFTER HOME CONSTRUCTION.
TREE IS TOO CLOSE TO HOUSE AND SHOULD
HAVE BEEN REMOVED WHEN LOT WAS CLEARED
SINCE ITS ROOT SYSTEM HAS BEEN SEVERELY
DAMAGED BY EXCAVATION FOR A BASEMENT 224
D-28 TREE WITH VISIBLE DAMAGE. EXISTING DAMAGE
SHOULD BE ASSESSED WHEN SELECTING TREES
FOR REMOVAL OR PRESERVATION 225
D-29 SECTION OF TREE TRUNK (FIGURE D-28) AFTER
REMOVAL. NOTE DAMAGE CAUSED BY
CARPENTER ANTS 225
D-30 EQUIPMENT TRAVEL IN THIS AREA HAS SERIOUSLY
DAMAGED ROOT SYSTEMS OF TREES MARKED FOR
PRESERVATION 226
D-31 ACCESS ROUTE FOR MATERIAL DELIVERY TO
BASEMENT HAS CUT ROOTS OF BEECH TREE ON
LEFT 226
D-32 WOODCHIPS BEING RETURNED TO FOREST 227
D-33 WOODCHIPPER BEING FED 227
D-34 DRAINAGE DITCH FOR "CONVENIENCE" OF
UTILITY CONSTRUCTION HAS BEEN CUT ON PRIVATE
PROPERTY WELL OUTSIDE OF RIGHT-OF-WAY 228
xv
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CROSS-INDEX
A Chemical Soil Stabilizers, Mulches, and Mulch Tacks -
pp. 22, 38, 39, 40, 48, 50, 51, 53, 55, 78
Aerospray® 52 Binder - pp. 63, 81
Aquatain - pp. 63, 83
®Curasol AE - pp. 65, 85
®CurasolAH - pp. 65, 87
DCA-70 - pp. 65, 89
Liquid Asphalt - pp. 39, 40, 70, 91
Petroset®SB - pp. 71, 93
Terra Tack - pp. 74, 75, 95
B Erosion and Sediment Control Structures - p. 97
Check Dam - pp. 15, 27, 32, 33, 51, 64, 98
Chutes/Flumes - pp. 37, 51, 58, 64, 67, 101
Diversion Dike - pp. 36, 37, 48, 57, 58, 66, 105
Erosion Check - pp. 35, 67, 109
Fabriform® Erosion Control Mat - pp. 15, 27, 67, 114
Filter Berm - pp. 37, 41, 48, 50, 57, 67, 119
Filter Inlet - pp. 41, 67, 123
Flexible Downdrain - pp. 36, 50, 51, 58, 67, 128
Gabions - pp. 13, 15, 27, 67, 132
Interceptor Dike - pp. 36, 37, 48, 50, 57, 58, 69, 136
Level Spreader - pp. 36, 58, 69, 140
Sandbag Sediment Barrier - pp. 41, 50, 72, 142
Sectional Downdrain - pp. 36, 50, 58, 73, 145
Sediment Retention Basin - pp. 17, 25, 41, 47, 57, 73f
xvi
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CROSS-INDEX
(Continued)
Straw Bale Sediment Barrier - pp. 41, 49, 50, 74, 159
C Fiber Mulches, Mulch Blankets and Netting - p. 163
Excelsior Blanket - pp. 22, 26, 34, 38, 40, 55, 67, 164
Fiber Glass Matting - pp. 34, 38, 55, 67, 167
Glassroot® - pp. 22, 26, 39, 55, 68, 169
Jute Netting - pp. 22, 26, 34, 38, 40, 55, 69, 172
Mulch Blanket -pp. 22, 26, 34, 38, 40, 55, 70, 176
Netting - pp. 26, 35, 38, 40, 55, 70, 179
Plastic Filter Sheet - pp. 24, 71, 182
Straw or Hay - pp. 22, 35, 38, 39, 48, 51, 53, 55, 68, 74, 183
Woodchips - pp. 22, 38, 39, 47, 48, 49, 50, 51, 53, 55, 76, 186
Woodfiber Mulch - pp. 22, 38, 53, 55, 76, 190
D Special Erosion and Sediment Control Practices - p. 193
Construction Coordination - pp. 25, 42, 44, 45, 49, 65, 194
Mulch Anchoring - pp. 22, 38, 39, 48, 50, 51, 55, 70, 195
Pumped Water Management - pp. 50, 72, 196
Roughness and Scarification - pp. 22, 37, 50, 51, 72, 73, 199
Stump Removal - pp. 51, 74, 203
Traffic Control - pp. 32, 44, 48, 49, 50, 53, 58, 75, 206
Tree Preservation - pp. 19, 20, 44, 47, 48, 50, 51, 54, 75, 211
Vegetative Filter Strip - pp. 18, 20, 25, 41, 44, 48, 50, 53, 57
67, 75, 218
Woodland Clearing and Excavation - pp. 44, 47, 50, 76, 222
xvn
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SECTION I
INTRODUCTION
The development of technology for the control of erosion and sediment
has been underway since the federal government became involved with
the problems associated with the drought of the "dirty thirties. " Prob-
lems were defined and practices were developed for their control.
Implementation began on a formal basis with the help of the Civilian
Conservation Corps, the Soil Erosion Service, etc. Over the years
conservation practices were developed. Terraces, grassed waterways,
contour farming, strip cropping. . . were put into use on farms across
the United States because the continued productivity of the soil could
be assured and crop yields very often could be improved by the use of
good conservation practices.
With the post World War II building boom came intensive concentrations
of people in and around established cities. "Suburbs, " "suburbia,
"suburbanites". . . were added to the American vocabulary and urban
sprawl became a part of the American way of life.
As the concentration of people in and around the cities became more
intense, concern for the environment became a topic of conversation.
With the passage of time individuals began to seek ways to protect the
environment. Groups of concerned citizens became active and their
efforts became widely publicized. The legislative, executive, and
judicial branches of local, state, and federal government became more
involved with each passing year.
With the advent of the 1960's, ecology and the environment were being
considered major issues. Human energy and dollar resources began to
be expended to slow the general environmental degradation that was now
so apparent. Surface mining of natural resources, manufacturing, power
generation, urban development, etc., were now being asked and required
to adjust their priorities and modes of operation in an effort to decrease
the rate of environmental decay.
The problems caused by ineffective erosion and sediment control from
urban development are similar in some aspects to those which occur
with unplanned and poorly managed use of land for agriculture. For
example, reducing the water absorptive and holding capacity of land by
removing its natural vegetative cover during land clearing accelerates
and increases the volume of runoff water from rain. Streams receiving
this runoff can swell to such an extent that their banks are breached. If
the runoff is significantly above that which occurs naturally, then there
is flooding with the possibility of loss of life. Loss or damage to property
can result. Changes in the natural runoff pattern almost always result
in scouring and movement of soil. This erosion on land can cause damage
to buildings, roads, and bridge foundations. When scoured soil is flushed
into streams or lakes, destructive sedimentation occurs. Fish and other
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aquatic life habitat is damaged or eliminated. The addition of large
amounts of sediment to streams fills in deeper channels. Runoff then
scours the upper banks of the stream because the stream's capacity
has been reduced and the water must rise. This scouring contributes
more soil to the stream, compounding the problem.
Many concepts have been generated in an effort to aid in this environ-
mental struggle. Research should lead the fight. Currently, environ-
mental research is obliged to fight "brush fires. " A great need exists
for applied research that addresses itself toward solution of major
problems - problems like sediment and erosion control.
In the middle I960's, erosion and sediment production associated with
urban development became a major concern. Sediment was recognized
as a pollutant. Legislation was introduced and, in some cases, passed
requiring that urban development implement measures to reduce the
ecological and environmental stress imposed by sediment generated on
construction sites. Specific problems were defined and practices for
their control were developed just as they had been "back in the thirties. "
However, now the problem was not focused on rural America. It now
included the development of "suburbia. " New products, techniques,
practices, etc. , were developed specifically for use on urban develop-
ment projects. Much of the technological advance has been made by
field trial and evaluation on sites under development. Some progress
came about bv altering methods that had for years successfully performed
"on the farm ' However, this type of progress is not sufficient. As
the technology is advanced, it must also be disseminated. People must
be trained to use the new techniques. The public can also expect to make
financial sacrifices, and token financial commitment will not suffice. If
the environment is to be saved, legal matters must be handled by lawyers
who are knowledgeable in the environmental sciences so that they can
intelligently argue for its cause. Legislative bodies must formulate and
pass workable laws - laws that will and can be funded and enforced. These
are only some of the concepts. There are, undoubtedly, many more - all
worthy of attention.
These guidelines attest to the fact that the work is underway. It is one of
several steps in the general scheme of environmental conservation But
it is the result of research - applied research that addresses itself to the
broad problem of sediment and erosion control. It is also a document
that is designed for broad use in the field. It can be used by both the lav-
man and the conservation specialist. It contains information that is
applicable to the regional development scheme and the development of a
single lot. It is designed for use -- use in the field -- the field of sedi-
ment and erosion control.
"Guidelines for Erosion and Sediment Control Planning and Implementaf "
is the first of three major documents being generated as part of the Joint
Construction Sediment Control Project being conducted in the Village of
Long Reach, Columbia, Maryland. This project is being operated by the
Department of Water Resources, State of Maryland, under an Environment
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Protection Agency demonstration grant. Hittman Associates, Inc., of
Columbia, Maryland, is the prime contractor for the project. Howard
Research and Development Corporation, the developers of Columbia,
the Columbia Parks and Recreation Association, Inc. , a nonprofit
corporation representing the community used, and various builders
are participants in this applied research project.
For the above reasons and others to be explained later, the principal
purpose of these guidelines is to help those responsible for, or engaged
in, urban construction prevent the uncontrolled movement of soil and
the damage it causes. The guidelines can serve those concerned in
several ways. First, it can provide guidance in the design and imple-
mentation of a complete sediment and erosion plan. It can also be used
as a primer for personnel interested in this field. There may be second-
ary benefits, as well. Avoidance of environmental destruction often can
prevent legal action to recover damages. Money can be saved in the
overall cost of development and maintenance. More natural and pleasant
surroundings will stimulate sales at higher prices and the reputation of
those engaged in development will be enhanced.
Instructions For The Use Of These Guidelines
Although it is a bound publication, it can best serve by con-
version to looseleaf form. The binding can be removed and
it can then be punched for looseleaf use. As a looseleaf
document, the new data, innovations, additions, etc. , in
the field of erosion and sediment control technology that are
sure to follow can be easily incorporated into this document.
References used in the preparation of this document are con-
tained in Section VII. Terms used that are technical in nature,
or that are not commonly used, are defined in the Glossary,
Section VIII. It should be consulted if there is doubt regard-
ing the meaning of a word used in the text or appendices.
A Cross-Index is also provided immediately following the
List of Figures. It lists each entry included in the Appen-
dices and those pages upon which the entry is mentioned in
the text. Ample space for notes is also provided in the
Appendices.
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SECTION II
PRELIMINARY SITE EVALUATION
A. General
The preliminary site evaluation is performed prior to the acquisition of
a parcel of land. In this evaluation, the physical features of the land
are evaluated to determine potential erosional hazards. Based on the
information acquired from the preliminary site evaluation, the general
requirements needed to avoid or minimize damage to land, water, trees,
and other vegetation can be determined.
The preliminary site evaluation should be performed by individuals
experienced in the siting and design of both structural and vegetative
erosion and sediment control practices. They should also be knowledge-
able in the earth and vegetative sciences and be capable of recognizing
the critical physical features affecting erosion and sediment control.
As a minimum, the preliminary site evaluation should include a thorough
surface reconnaissance of the potential development site and a familiar-
ization with those references which describe the characteristics of the
local geology, soil, and hydrology. In the case of development where
extensive grading is anticipated, it is also desirable to perform a pre-
liminary subsurface investigation. It will provide information on the
geologic, soil, and groundwater conditions that must be considered.
Down to a depth of approximately three feet, subsurface information can
generally be obtained using a hand auger. For depths between three and
ten feet it is generally desirable to use either a standard backhoe or
drilling machines. Below 10 feet in depth, it is generally necessary to
use drilling machines.
B. Maps and Airphotos
The use of all available topographic, geologic, soils, and zoning maps,
and airphotos is essential for a good preliminary site evaluation. To
the experienced and trained individual these documents provide a valuable
source of information on physical features that relate to erosion and
sediment control. In addition, these documents should be used as base
maps on which to record the locations of critical physical features and
to make preliminary layouts of the potential development.
Maps and airphotos are often available at slight cost from several
governmental sources. Probably the most widely used source of topo-
graphic maps is the United States Geological Survey, which publishes
and sells quadrangle maps. These maps normally have a scale of
1:24, 000 (one inch = 2000 feet) and a contour interval of 20 feet. Due
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to their small scale and large contour interval, these maps usually have
value only in studying the gross topographic features of large areas in-
volving many acres.
One of the most valuable sources of mapping information for preliminary
site evaluation is the local County Soil and Water Conservation District
Office. County District Offices are assisted by the Soil Conservation
Service of the United States- Department of Agriculture and maintain a
file of airphotos of their counties which are available for inspection.
These airphotos provide a wealth of information important to a prelim-
inary site evaluation. Stereoscopic pairs of airphotos permit the view-
ing of large areas in three dimensional perspective. As a result, land
forms, vegetative features, hydrologic features, and man-made features
are clearly visible. Often these photos have been used to prepare a
photo mosaic which permits an overall view of the potential development
site and shows the relative locations of the various vegetative, drainage,
and man-made features. A photo mosaic or orthophotograph is also use-
ful as a base map on which to record the location of critical physical
features.
Other important sources of maps are the state geological surveys. They
often publish a state geologic map and, in some states, also county geo-
logic maps. These maps show the recognized and inferred rock outcrop
areas of the various geologic units and also display gross topographic
features. To a geologist, the information found on these maps provides
an important insight into recognizing possible limiting physical features
related to erosion and sediment control. For most developments, these
maps would not be an important source of topographic information be-
cause of their small scale.
County highway and planning and zoning maps are also often available
and useful in developing the information required for a preliminary site
evaluation.
Inquiries should be made into the regulations and restrictions that apply
to the development of property. This inquiry should be made early in
the preliminary survey in order that the proposed development plans can
be formulated to comply with the law. Information regarding legislation
that may be pending should also be acquired since the proposed develop-
ment may be influenced by legislative enactment.
Agencies at the federal, state, county, municipal, etc., levels should
be contacted for specific information on legislation governing develop-
ment in the area being considered.
C. Soils and Geological Information
In addition to the various types of maps, several publications that pro-
vide general information on local soil and geologic conditions are avail-
able to the engineer and scientist making a preliminary site evaluation ~
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The most useful publications that are generally available for public use
are the county soil survey reports, prepared and published by the Soil
Conservation Service of the United States Department of Agriculture in
cooperation with state agricultural experimental stations. The reports
which have been published within the last few years contain considerable
amounts of information pertinent to erosion and sediment control evalua-
tions. For example, they contain photo mosaics, generally printed at
a scale of 1 inch = 0.25 miles, upon which soil maps, showing soil map-
ping units, have been superimposed. Although these airphotos are not
suitable for stereoscopic viewing, they do show the major drainage pat-
tern of the area including a delineation of floodplain soils and the relative
locations of roadways, woodlands, and agricultural areas, in addition to
the soil types. Tables are keyed to the soil maps and contain estimated
engineering characteristics of the various soil types and an evaluation of
their suitability for various engineering usages. Engineering character-
istics generally considered in sediment and erosion control design are
as follows:
(1) Depth to bedrock
(2) Depth to water table
T
(3) Unified and AASHO soil classifications
A
(4) Grain size gradations
(5) Permeability
(6) Available water capacity
(7) Reaction (pH)
(8) Shrink-swell potential
(9) Moisture-density relationship
With regard to the suitability of the soil types for various engineering
usages, the following topics are generally covered in the soil survey
reports:
(1) Suitability as source of topsoil
(2) Pipelines (construction and maintenance)
(3) Road and highway location
(4) Pond and reservoir sites
(5) Dikes, levees, and embankments
(6) Drainage systems
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(7) Irrigation
(8) Terraces and diversions
These soil suitability data are often related to erosion and sediment
control considerations.
The state geological survey office is another source of published infor-
mation for use in making a preliminary site evaluation. In many states
water resource bulletins are published for the counties. These bulletins
often contain a considerable amount of statistical information on the
groundwater characteristics of the various geologic units and on the
hydrology of the various drainage basins in the counties.
Where fairly specific subsurface information is desired, the county
and state highway departments should not be overlooked. These public
agencies often keep on record the results of roadway and structural
foundation investigations performed in conjunction with their studies.
This is especially true in regard to the more recent highway programs.
These results generally include boring and test pit logs, showing soil
and bedrock types and groundwater measurements, and the various
engineering properties of the soils and bedrock as measured in the
laboratory and in the field.
D. Technical Assistance
Technical assistance regarding sediment and erosion control measures
is generally available to developers, designers, builders, etc. , from
several state and local governmental agencies. In most counties this
type of technical guidance can be provided by the County Soil and Water
Conservation District. Assistance in interpreting the county soil survey
report can be provided, and in many cases District personnel are able to
inspect the proposed development site.
The office of the State Geological Survey can be contacted for information
regarding geology and hydrology and their potential problems. This
agency can usually provide general information concerning the site based
on the pertinent literature, the geologic and topographic mapping, the
statistical records, and personal experience. Where the problem will
require a detailed field reconnaissance and possibly a subsurface investi-
gation, a geological consultant should be employed.
In many parts of the nation, the county or city public works departments
can also provide technical assistance.
In those states which have enacted erosion and sediment control laws
technical assistance can generally be obtained from conservation special
ists employed by the county and state governments. ^
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E. Evaluation of Prime Physical Features
A preliminary site evaluation requires an assessment of the prime
physical features which are critical to erosion and sediment control and
have aesthetic value. It is important that these features be studied and
that they be delineated on a site map for use in evaluating different lay-
out schemes.
1. Land Type
For the purpose of erosion and sediment control planning, the proposed
development site should be categorized into three basic land types.
They are, in order of potential erosional severity, as follows:
(1) Barren areas
(2) Agricultural areas
(3) Woodland areas
barren areas (Figure 1) are nearly or totally void of any vegetation.
These areas will require considerable grading and elaborate and costly
vegetative and structural measures to control erosion and sediment
iring and after construction.
* „-- :- '•• " -V,
. I -?,*fe-
FIGURE 1. Barren area
9
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Agricultural areas (Figure 2) are open areas under cultivation or capable
of being cultivated. Unless these areas are planted in grain crops, agri-
cultural areas generally support a stand of grasses, legumes, or herbaceous
plants.
FIGURE 2. Agricultural area
Woodlands (Figure 3) is a self-explanatory term. Woodlands are described
as mature stands, pole stands, and mixed stands. Mature stands (Figure 4)
generally contain trees with trunk diameters of 10 inches and greater,
measured at chest height. Pole stands (Figure 5) are thick stands of tall,
small crowned trees with trunk diameters between 6 and 10 inches. Mixed
stands (Figure 6) contain both mature sized and pole sized trees. Mixed
stands generally occur in woodlands that have been selectively lumbered,
whereas pole stands generally occur on tree plantations or in woodland
areas that have been previously clear cut or burned over.
Mature trees with full crowns have the highest aesthetic value. However,
they are less likely to recover from injury than are smaller and younger
trees. Mature trees, due to their crown size, bark structure, trunk
strength, and broad root structure, are more able to resist the changes
in wind and sun exposure resulting from extensive clearing. Crowded
pole sized trees often have constricted crowns and root systems in pro-
portion to their height. This condition reduces their ability to withstand
exposure to intense sun and wind.
10
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.FIGURE 3. Woodland area
FIGURE 4. Woodland area - mature stand
11
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.-; i'~ •••' *-**••• '"I", - **•%, "**
i
FIGURE 5. Woodland area - pole stand
FIGURE 6. Woodland area - mixed stand
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2. Soil and Rock
The presence of highly erodible soils is a very critical physical feature.
This is especially true if these soils occur on moderate to steep slopes.
It is not always possible for the layman to recognize a highly erodible
soil horizon. It may be masked by a stand of vegetative cover or it may
exist as a soil horizon beneath a surface soil of different character.
Highly erodible soils are usually characterized by a deficiency of soil
particles that have cohesive strength. This cohesive strength is usually
a function of the clay sized (colloidal) fraction of the soil horizon. How-
ever, there is no absolute rule of thumb because soil characteristics
can be variable even within the boundaries of individual soil mapping
units.
It is very important, however, that the presence of highly erodible soils
be confirmed at an early stage of the site survey. Professional assistance
should be obtained if there is any doubt. The cost of this professional
assistance will be a good investment if the serious problems associated
with erodible soils can be ascertained early in the planning phase of any
development program.
A knowledge of the occurrence of rock outcrops at a proposed develop-
ment site is also important in making a preliminary site evaluation.
Rock outcrops, when properly positioned within a residential community,
have high aesthetic value. They do, however, create difficulties when
installing underground utilities and when excavating for road cuts and
building foundations.
Where rock will be encountered in excavations, consideration should be
given to stockpiling the rock for use in erosion and sediment control
structures. Rock has use as riprapand for fill in wire gabions (Appendix
B) for prevention of erosion along stream channels and shorelines. Rock
is commonly used to protect drainage ditches (Figure 7) where the grade
is severe and is also used as an energy dissipator at the outlets of
drainage conduits. Some durable rock types also have value as a land-
scape material.
3. Streams
Streams deserve very careful examination in any preliminary site evalua-
tion. Not only are they the recipient of sediment from the development
site and a transporter of sediment to private and public properties down-
stream from the development, but they can themselves contribute to the
sediment load through channel degradation and bank erosion.
13
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FIGURE 7. Channel lined with hand placed rock
In an urban development, three major factors contribute to increased
stream erosion. These are:
(1) Restriction of the stream channel due to sedimentation
or construction
(2) Increased runoff due to decreased infiltration in the
runoff area
(3) Destruction of the natural vegetation along the stream
banks
Channel restriction causes increased flow velocities and these, in turn,
are major contributors to erosion and flooding. Decreased infiltration
also delivers more water to downstream areas by causing deeper and
faster stream flow. These characteristics contribute to the compounding
of downstream runoff problems.
If extensive damage due to flooding, erosion, and sedimentation is to be
averted, several factors must be considered by the engineer or scientist
when evaluating a stream. They are:
a. Size of Stream. For small streams running through large
developments, the erosional effect of increased runoff is certainly
14
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a major consideration in sediment and erosion control. For
large streams or rivers, the effects of the increased runoff
and erosion contributed by an urban development along the
stream banks is more easily controlled.
b. Stream Gradient. The gradient of the stream will, to a
large extent, affect its sediment transport capability. Wide
floodplains, meandering courses, and sediment buildup in the
channel are indications that the gradient of the channel is
shallow and that increased sediment load will cause additional
sedimentation of the channel. This condition, in combination
with increased runoff due to development of the watershed,
could result in flooding during periods of concentrated heavy
precipitation.
c. Alignment Configuration. Since streams are one of the most
dynamic entities in nature, it should be recognized that room for
normal channel migration and adjustment to newly imposed runoff
stress must be maintained or provided. Therefore, recreation
area construction, i.e., walkways, bridges, etc., must be care-
fully sited and planned if they are to survive.
d. Bank and Bottom Conditions. Where the stream banks are
high and steep, additional runoff from the watershed due to urban
development causes serious streambank erosion problems. This
problem can be especially severe at bends in the stream where
the force of the flowing water is directed against the outside (cut-
bank) of the bend. Erosion control structures, such as riprap,
Fabriforrrr or gabions (Appendix B), may be required along
the outside of the bend in order to prevent erosion.
Every attempt should be made to preserve or enhance the vegeta-
tive cover of stream banks, especially grasses, sedges, and
woody shrubs with dense fibrous root systems. In poorly vege-
tated areas along fairly straight stretches of steep stream bank
it is necessary to flatten the slopes (generally 3:1 or 4:1, de-
pending on bank height) and establish a good vegetative stand in
order to control streambank erosion.
For youthful streams, i.e., those streams where downcutting
is in progress, the condition of the stream bottom should be
studied to see if the anticipated increase in flow will negatively
affect the stream bottom. If serious erosion is anticipated,
grade control structures must be constructed along the stream
course. These structures are generally check dams (Appendix
B) constructed of either wood, concrete, or rock.
15
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4. Floodplains
Floodplains are an integral part of the drainage system of the area, not
something apart from the drainageway. During periods of intense run-
off they become inundated by flood flow and act as an extension of the
stream itself. Therefore, the integrity of the floodplain (Figure 8) must
be preserved.
FIGURE 8. Floodplain in developed area
Development on floodplains is wrong, both from the standpoint of pro-
tection of life and property during periods of flood flow and from the
standpoint of erosion and sediment control. Local building codes and
state floodplain regulations should be consulted to determine what
legally constitutes an undevelopable floodplain. In applying the require-
ments of the local building code, the developer should keep in mind that
in an urban development, the runoff characteristics will be much more
severe during and after development than prior to development. If the
undevelopable floodplain is defined in the code as the area flooded by a
100 year storm event, the developer should calculate the limits of the
floodplain on the basis of a 100 year storm occurring after the develop-
ment is complete, rather than before development when runoff is less.
16
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5. Impoundments
With proper planning, man-made ponds, such as farm ponds, can be
effectively utilized for stormwater retention and sediment collection
during construction. Properly constructed with sufficient area and
capacity, it is desirable to preserve such ponds after development for
aesthetic and recreational benefits and for runoff control. These
practices are encouraged.
Natural impoundments, such as lakes, are aesthetically valuable physical
features and should be protected against sediment damage. During the
preliminary site evaluation, the existing conditions of the lake and shore-
line should be evaluated in order to determine what deleterious effect
sedimentation could have on the ecological and physical features of the
impoundment.
In evaluating man-made ponds for possible use in stormwater manage-
ment and sediment collection, it is necessary to determine whether or
not the pond is of sufficient capacity to safely handle the required design
flow as determined for anticipated conditions occurring during and after
development. When the impoundment trap efficiency is severely reduced
by sediment buildup, it will be necessary to rejuvenate the pond by re-
moving the sediment. Sediment must be disposed of in a manner which
will not permit its reintroduction into the drainage system.
6. Groundwater Conditions
Groundwater conditions are often overlooked in evaluating a possible
development site. If not considered, groundwater (Figure 9) can cause
very serious construction difficulties that directly and indirectly affect
erosion and sediment control. For example, groundwater seepage from
roadway cuts prevents the establishment of a good vegetative cover and
causes soil to slough into the ditches where it is directly introduced into
the drainage system.
The most telling indication of a high groundwater table is the presence
of springs. Another indication is mottling in the soil. This mottling
reflects a seasonal high water table.
7. Vegetative Cover
A dense vegetative cover of grass, weeds, shrubs, vines, or trees
is very effective in preventing erosion on steep slopes, swales, and along
drainageways and impounded waters. It is important that the vegetation
on a proposed development site be evaluated in terms of its benefit to
erosion and sediment control. For example, if steep slopes, which would
be subject to severe erosion when denuded, are covered with a good stand
of natural vegetation, serious consideration should be given to not dis-
turbing the existing vegetation during proposed development.
17
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FIGURE 9. Groundwater table exposed in a basement excavation
The vegetative cover along waterways (Figure 10) and around impoundments
must be protected, since it serves as a soil stabilizer and as a filter for
sediment-laden water flowing into water courses. The most effective
natural filters are thick stands of grasses and legumes. However, any
vegetation, even if it is weeds, is considerably better than naked earth.
FIGURE 10. Well established vegetation in a minor drainageway
18
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SECTION III
PLANNING
A. General
Planning is the process by which a development and/or construction plan
is formulated. For larger developments, the planning process can be
broken down into four progressive steps as follows:
(1) preliminary site investigation
(2) preliminary design
(3) subsurface investigations
(4) final design
For small developments, steps (1) through (3) are commonly combined.
In each step of the planning process, erosion and sediment control,
including stormwater management, should be one of the major considera-
tions. To be successful any plan must also include close scheduling and
coordination of construction activities and provision for the maintenance
of conservation practices. Stormwater management "detention practices"
should be developed to reduce the impact of minor storms which cause
accelerated erosion of stream channels and drainageways and should not
be confused with control of flood flows.
B. Preliminary Site Investigation
1. Delineation of Critical and Prime Physical Features
During the preliminary site investigation, the critical physical features,
as discussed in Section II of this document, must be evaluated in terms
of their relationship to erosion and sediment control and their aesthetic
value. Those critical physical features which are determined to have a
significant influence on erosion and sediment control or which have a
high aesthetic value requiring protection should be delineated on a suit-
able base map of the development site. This procedure involves little
extra work if a good preliminary site evaluation has been performed
prior to acquisition of the site.
In addition to those critical and aesthetic physical features discussed in
Section II, it is also necessary to show the complete drainage system on
the topographic map. This must be done in the planning stage.
Furthermore, for small woodland developments, it is recommended that
the individual prime trees be located on the topographic map. For large
woodland tracts, especially those where the topographic map was developed
19
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from airphotos (photogrammetric map), it may be impossible to
delineate individual prime trees at this time, unless they are of extreme
economic and aesthetic value. However, as a minimum, the large wood-
land tract must be delineated on the basis of major stand types and age
classes, as discussed in Section II.
2. Detailed Topographic Mapping
In order to provide enough detail with which to delineate the drainage
system and prepare an erosion and sediment control plan that will protect
each lot in the development and provide sufficient space on which to re-
cord critical physical features, the topographic map should have a scale
of 1 inch = 40 or 50 feet and a contour interval of two to five feet. In
addition, it is recommended that the topographic mapping be extended a
minimum of 100 feet beyond the boundary of the development site in
order to assess the affect that erosion and sediment deposition may have
on adjacent properties. This extension facilitates the integration of
on-site erosion control planning with the surrounding topography.
C. Preliminary Design
During the preliminary design phase, every attempt must be made to
site the development in a manner which will minimize damage to those
physical features which are critical to erosion and sediment control and
those physical features that have high aesthetic value.
Grading damage caused by roadway and home construction should be
held to a minimum by avoiding steep slopes which will result in high
cuts and fills and by following the natural ground contour as closely as
possible.
Extreme care must be exercised in locating drainageways to be sure that
the resulting channel gradient and related discharge velocity will not
cause erosion of the vegetative drainageway liner. In the event that
these limiting factors are exceeded, costly structural measures, such
as concrete or stone lining or grade control structures, will be required.
Whenever possible, underground utilities should be located in such a manner
that an undisturbed vegetative filter strip (Figure 11) can be preserved be-
tween the utility and adjacent drainageways during construction. The
location should also allow for stockpiling of excavated soil on the up-
slope side of the trench (away from the channel).
20
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,
FIGURE 11. Natural filter strip separating bare soil (foreground)
from a stream channel (dark vegetation in middleground)
D. Subsurface Investigation
The subsurface investigation must not be limited to those geological
features and soil characteristics which are classically related to the fields
of soils and geological engineering. It must also be utilized to determine
the erodibility of the soils and their capability to sustain a long-term
vegetative cover. It is essential that the designer take these factors into
consideration in the development of his grading plan.
1. Vegetative Stability
As a general rule of thumb, a 50 percent (2:1) slope is assumed to be
the maximum slope upon which vegetation can be satisfactorily established
and maintained. However, maximum vegetative stability cannot be
attained on slopes steeper than 33 percent (3:1). Optimum vegetative
stability requires slopes of 25 percent (4:1) or less. The maximum
slope should only be applied to ideal soil conditions where the soil is
not highly erodible and has an adequate moisture holding capacity.
21
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For droughty soils (those which exhibit a poor moisture holding capacity
due to excessively high permeability and a low percentage of fines) and
for highly erodible soils, the maximum permissible slope should be
considerably less than 50 percent.
Droughty soils generally have less than 30 percent fines. Where these
soils are encountered in cut areas and where reconditioning by the addition
of fines or suitable topsoil is not planned, it is strongly recommended
that the cut slopes not exceed 33 percent (3:1) in order that a satisfactory
vegetative cover can be established. Furthermore, these soils must be
planted with warm season, deep rooted, drought resistant grasses and
legumes suited to that particular region. For more drought resistant
soils with greater than 30 percent fines, conventional cool season grasses
and legumes of the region can be utilized.
Where fills are to be constructed with droughty soil and where some finer
grained, drought resistant soils are also available, a portion of the
drought resistant soil should be segregated for later use in top dressing
the fill.
Soils containing excessive amounts of fines, especially clay sized par-
ticles such as clays and clayey silts, can also be difficult to stabilize
with vegetation. The tight structure of many of these soils inhibits root
development and the infiltration of moisture. Cut slopes in these types
of soils must be kept as flat as possible in order to enhance infiltration.
On flatter slopes where sloughing will not occur, it is recommended
that the slopes be top dressed with topsoil or other suitable soil or that
the existing soil be reworked by scarification and the addition of organic
material and fertilizer. On steep cut slopes, the existing soil should
be reworked as the cut progresses and while the slope is accessible to
scarification, spreading, and compaction equipment.
Roughening the soil surface enhances the establishment of vegetation on
any soil slope. This practice favorably affects germination because it
reduces sheet erosion and increases water infiltration. The soil surface
should be roughened along the contour in order to reduce the chance of
rilling. Although this practice favorably affects the establishment of a
vegetative cover, it should not be considered as a substitute for mulching
practices (Appendices A, C, and D).
The establishment of locally adaptable ground covers and shrubs assures a
long lived vegetative erosion control cover on critical slopes. Therefore
it is often desirable to include seeds of these plants along with the con-
ventional hydroseeding of grasses and legumes. Overplanting grassed
slopes with ground covers or shrubs before vegetative deterioration
results in slope erosion, or planting directly to ground covers and shrubs
using erosion control mattings or mulches (Appendices A, C) to prevent
erosion during the period of establishment are also acceptable practices
22
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2. Soil Erodibility
Soil erodibility is dependent upon several physical features. These in-
clude the relative proportions of sand, silt, and clay in the soil; the
organic content of the soil; the soil structure; and the permeability of the
soil. Knowing these parameters and by using one of several methods
available for the computation of gross erosion, a measure of soil erodi-
bility, expressed as tons of removed sediment per acre of surface area,
can be determined.
Well graded soils generally exhibit a relatively high resistance to ero-
sion because they have both cohesive and intergranular strength. On the
other hand, loose granular soils, especially those which are fine grained,
are highly erodible when exposed on steep slopes. Some types of clay
soils are less erodible than others because they have greater cohesive
strength; however, many of the indurated clays and silty clays that
contain expansive clay minerals are susceptible to excessive erosion by
slaking and alternate wet and dry cycles.
3. Soil Chemistry
The engineering soil testing program must be expanded to include testing
to determine the pH and nutrient level of soils that will be brought to the
surface by construction activities since these soils will soon have to
support vegetation. In addition, in those regions of the country where
toxic soil compounds are commonly encountered, testing must be per-
formed to determine the existence or nonexistence of these compounds
so that corrective measures can be taken.
pH problems are common and must always be investigated. Excessively
acid soils will require periodic applications of crushed or pulverized
limestone, dolomitic limestone, etc., in order to maintain a good vege-
tative cover. In some cases the use of vegetation with acid tolerant
characteristics is possible. The major elements which affect the nutrient
level of the soil are nitrogen, potassium, and phosphorus. Soils deficient
in these nutrients will require periodic applications of proper fertilizers,
selected on the basis of soil tests. Excessive concentrations of certain
nutrients can be toxic to the vegetation.
4. Ground water
Groundwater seepage is caused by the exposure of the groundwater table
and can cause serious erosion and sediment control problems. Where
subsurface investigations reveal severe high water table conditions,
every effort must be made to minimize disturbance of these potential
problem areas. The best practice is to avoid disturbance where these
conditions exist.
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This is especially true with fluid clay formations. On steep cut slopes,
seepage can cause severe sloughing in erodible soils. Excessive seep-
age also prevents the establishment of a satisfactory long term vegetative
cover.
Where seepage is encountered in ruts, costly structural measures will
often be required in order to reduce or eliminate the erosional problem.
Where the seepage is confined to a small localized area, the water can
generally be trapped below the surface by using perforated drain pipe
and graded stone and sand filters. It must then be lead safely downslope
to a satisfactory disposal area. Where the seepage extends for a con-
siderable distance along a slope and where the slope is accessible to
construction equipment, a longitudinal pipe and stone underdrain will be
required. On steep slopes, inaccessible to construction equipment, it
will be necessary to surface the slope with filter cloth (Appendix C) and
crushed stone or other suitable materials.
5. Topsoil
To be satisfactory, a topsoil must contain at least 30 percent fines
(material passing the 200 sieve) and should conform to the state standards
for organic content, weed seed content, and noxious weed content.
Contrary to popular belief, the quality of some topsoils does not justify
their salvage and stockpiling for later use as top dressing on graded
slopes. If topsoil quality is substandard, it will be necessary to estab-
lish vegetation by adding required nutrients, chemicals, etc., directly
to the exposed soil surface. A satisfactory seedbed can be attained by
working these materials into the upper four inches of the soil by mechan-
ical means. Nutrient and chemical additive quantities must be established
on the basis of soil test results, not guesses.
E. Final Design
1. Stabilization of Major Waterways
Major waterways include all natural or constructed waterways which
can be classified as either permanent or intermittent streams.
The individual or combined effects of increased runoff, channel con-
striction either caused by siltation or construction, and destruction of
natural vegetation greatly accelerate waterway erosion. All of these
conditions commonly occur with urban development. Some of these
effects can be totally avoided or minimized through good site planning.
On large developments, the erosive effect of increased runoff can be
minimized through stormwater management. This often requires the
construction of storage ponds in critical areas of the watershed which
will provide for the collection and storage of runoff during periods of
24
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of heavy precipitation. The ponds should be constructed to allow the
gradual release of the stored runoff during low flow periods. Storage
ponds also favorably affect infiltration and evaporation, both of which
reduce the total runoff. They also collect sediment which would oth-
erwise be deposited in the waterways or other downstream sites.
Filling of floodplains must be avoided, except at roadway crossings.
Where crossings are made, the conduits must be adequately sized,
keeping in mind that the runoff will be much greater after construction
has been completed. Conduits must be placed so that erosion of the
stream banks and channel will not be accelerated in downstream areas.
Above all, the natural vegetation, whether it be grasses, brush, or
trees, along and adjacent to natural waterways must be protected from
construction activities and preserved in its natural condition.
Vegetation along waterways is beneficial to erosion and sediment control
in three important ways. First, the dense rootmat helps hold the soil
in place. Secondly, the foliage, in the case of grasses, legumes, and other
low growing plants and dead litter, such as leaves, filters out sediment
from the overland flow. Vegetation also dissipates the erosive energy
from falling raindrops, a most important contribution to sediment and
erosion control.
In the event that the above mentioned practices cannot achieve satisfactory
erosion control, induced vegetative and structural practices will be
required to control the problem.
Vegetative measures (Figure 12) are both practical and economical in
many cases where one or more of the following conditions exist:
(a) Poor quality vegetative cover
(b) Relatively flat terrain
(c) Low stream banks
(d) Tangential flow
(e) Low flow velocity
(f) Fertile soil
Prior to planting the vegetation, the banks will have to be graded back
on a fairly flat slope, preferably 25 to 33 percent or flatter. Although
excavation will destroy any existing vegetation on the bank, it is pre-
ferred over filling, since excavation increases the capacity of the chan-
nel rather than constricting it. Excavation is less likely to cause severe
sediment pollution problems. With regard to the control of sediment
pollution from stream bank modification, it is also desirable that the
grading be performed during periods of low precipitation and that the
work be staged so as to minimize the time of soil exposure.
25
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FIGURE 12. Vegetative streambank stabilization
Vegetation for use in stream bank stabilization should be selected on the
basis of its tolerance to the following factors:
(a) Erosive forces
(b) Soil moisture
(c) Sedimentation
(d) Soil conditions
In most cases, it is desirable to use strip planting techniques. This
involves the planting of a strip of wet soil tolerant, highly erosion resis-
tant vegetation in the critical area near the water line, and the planting
of conventional robust rooted grasses and legumes above the critical
zone. For added protection in selected locations, wet soil tolerant
bushes and trees can be planted near the water line. In order to protect
the graded and planted areas until a strong stand of vegetation is estab-
lished, it is recommended that an erosion control netting or blanket
(Appendix C) be utilized in addition to normal mulching practices.
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Assistance in selecting local types of vegetation for use in waterway
stabilization is available from the local soil and water conservation
district, the state forest services, fish and wildlife agencies, and others.
Vegetative measures alone may not be able to resist the erosive forces
at obstructions and bends in the streams. In these cases, channel main-
tenance or structural measures (Appendix R) will be required.
Indiscriminate removal of obstructions such as logs or boulders should
not be encouraged since they are required by fish and other aquatic life.
These obstacles, whether they be debris or bends in the channel, are
natural energy dissipators, and their removal increases the velocity of
flow and thereby intensifies erosion at critical areas further downstream.
Straightening is also undesirable since it steepens the stream gradient.
Steepened gradient increases the rate of downcutting in the channel or
it may rejuvenate the downcutting cycle in a stable channel. Headwater
gully erosion is also encouraged. The removal of recently deposited
sediment from the stream channel is beneficial, since it returns the
stream to a more stable and more natural alignment and channel
configuration.
Structural measures for protection of natural waterways against erosion
fall into two types. The first type of structure is known as a grade control
structure while the second type is commonly called a bank protection
structure. Grade control structures are utilized to control the gradient
of the waterway channel in a manner that will reduce the velocity of flow
and thereby minimize both channel and bank erosion.
The most common grade control structure is the check dam (Figures
13, 14, and 15). Check dams are short dams constructed of a wide
variety of materials including logs, treated lumber, stone, concrete,
and synthetic materials which flatten the slope of the stream and dissipate
energy. Stone or concrete should be placed in the high energy area at
the downstream toe of the check dam in order to prevent undercutting of
the structure. Check dams should be used with caution on streams which
are susceptible to flooding, since they reduce flow rates and thus increase
the chance of flooding.
There are two types of bank protection structures; revetments, and
deflectors. Revetments comprise a wide variety of both rigid and flexible
structures which are used as an erosion resistant facing on stream banks
and lake shores. The flexible type of structure is by far the most desir-
able and is generally more economical for stream bank protection.
Flexible revetments, such as riprap, Fabriform® mats, gabions
(Appendix B), etc. , have an advantage over rigid revetments, such as
asphalt paving or monolithic concrete, because they are able to adjust
to minor changes in foundation conditions without losing their integrity.
The most flexible and the most common revetment type used for stream
bank protection is randomly placed stone riprap. It is composed of loose
stone placed on a sand/gravel filter and/or filter cloth. Other types of
flexible revetments, although not nearly as flexible as stone riprap, are
gabions (Appendix B), Fabriform® mats (Appendix B), interlocking
concrete blocks, and steel or concrete tetrahedrons.
27
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FIGURE 13. Check dam with energy dissipator
.
'
FIGURE 14. Combination of check dams and lined channel
28
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FIGURE 15. Check dams (weirs) constructed of wood
The type of revetment selected for a particular bank condition will depend
upon the strength requirements, the cost, length of required service,
and aesthetic factors. In areas not requiring the extreme durability of
randomly placed stone riprap, or in areas where rock is not readily
available, other types of revetments may, for economic, fish and wildlife
habitat, or aesthetic reasons, be more desirable.
Common types of rigid to slightly flexible revetments include concrete
or asphalt paving, grouted stone riprap,and sacked concrete (Figure 16).
To be effective, a rigid type revetment requires a firm, stable foundation
and careful construction. Where fills are being protected, a high degree
of compaction is required beneath the revetment to BrexgnjLexcessive
settlement. To prevent undercutting at the toe," all revetments should be
carried several feet or more, depending on the design analysis, below
the existing ground surface. For rigid and for some partially flexible
types of revetments, an extra margin of safety against undercutting is
commonly achieved by placing adequately sized loose stones at the toe
of the revetment. When properly constructed and maintained,rigid
types of revetment can perform adequately as erosion control structures.
They can therefore be considered when selecting and designing a bank
protection revetment if other flexible types cannot be utilized.
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FIGURE 16. Sacked concrete revetment
All flexible and most rigid revetments are placed on a grade of approxi-
mately 50 percent (2:1). Several types of rigid revetment, including some
varieties of gabions, wood sheet piling,and metal sheet piling, are
constructed with a vertical face. These types of revetments are commonly
used where water access, such as for boat traffic, is essential. The
vertical types of revetment are also used as retaining walls in situations
involving the filling of floodplains. From the standpoint of erosion and
sediment control and stormwater management, such reclamation work
is undesirable, since it constricts the channel and thereby increases the
likelihood of erosion downstream of the construction area. It also in-
creases the chance of flooding upstream from the constriction.
The other form of bank protection structure, the deflection structure,
usually consists of a stone, concrete, or wooden groin which angles
outward from the shore in a downstream direction and deflects the current
away from a critical area of the stream bank. This type of structure
should only be used in large streams where the deflected current will
not jeopardize the opposite stream bank. In constructing a groin-type
deflector, it is extremely important that the foundation be protected on
both the upstream and downstream sides against scour damage. This is
generally accomplished by placing the foundation below the anticipated
scour depth and by placing a flexible armor blanket of durable, properly
sized stone or concrete fragments along the upstream and downstream
edges. This protection must also be provided up the stream bank to an
elevation that is above maximum high water flow.
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Advice in selecting the type of revetment suitable for a given condition
can be normally obtained from the following public agencies:
(a) United States Army Corps of Engineers
(b) United States Bureau of Reclamation
(c) United States Forest Service
(d) Soil Conservation Service (district and state offices)
(e) State geological survey
(f) State department of natural resources (water
resources section)
(g) State highway department
(h) County engineering department
(i) Universities
Many types of materials, covering a wide range of costs, are marketed
for use in constructing bank and shore protection structures. A selection
of the material best suited for a given condition should depend on an
analysis of the following factors:
(a) The ability of the material to stand up to the stress
conditions occurring on-site
(b) The initial cost and availability of construction material
(c) Maintenance cost
(d) Service life as determined for the conditions
occurring at the site
(e) Aesthetic considerations
(f) Replacement cost
A good engineering and economic evaluation requires mathematical and
empirical analysis, a knowledge of the available products and their
serviceability, and the ability to accurately assess the site conditions.
When the planner is not experienced in these matters, a qualified consul-
tant who is skilled in erosion and sediment control work must be retained.
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The following publications are also available for reference in designing
bank and shore protection structures:
(a) U.S. Department of Transportation, Federal Highway
Administration, Bureau of Public Roads, "Use of Riprap
for Bank Protection)' Hydraulic Engineering Circular
No. 11, June 1967.
(b) State of California, Department of Public Works, Division
of Highways, "Bank and Shore Protection in California
Highway Practice, " November 1970.
2. Stabilization of Minor Waterways
Minor waterways include all natural and constructed waterways, such as
roadway draining ditches, drainage swales, or diversion ditches, which
do not fall under the category of either permanent or intermittent streams.
a. Location of Minor Waterways. The location and design of
minor waterways are of considerable importance to a good program
of erosion and sediment control. The waterways which collect
and transport the surface runoff to the streams in the watershed
are one of the major sources of sediment pollution, both during
the construction phase and long after construction is complete,
if they have been improperly designed, poorly constructed, or
inadequately maintained.
Whenever possible, the planner should preserve the natural
drainage system. When natural waterways are utilized, care
should be taken to preserve the natural vegetation during the
construction phase. Traffic must not be allowed in the waterway.
It should be realized, however, that the natural vegetation may
not, by itself, be able to resist the additional erosive force
contributed by increased runoff from the developing or developed
area. When this occurs, it will be necessary to reinforce the
natural vegetation with additional planting or to resort to structural
measures when vegetative practices will not suffice.
b. Construction of Vegetated Waterways versus Lined
Waterways"! The utilization of vegetated waterways, rather
than concrete or asphalt lined waterways, is desirable from the
standpoint of stormwater management. The vegetated waterway
maximizes the loss of surface runoff through infiltration, whereas
the lined waterway allows no infiltration to occur. For the same
reasons, it is more desirable, when physical conditions are too
severe for the satisfactory establishment of a vegetative cover
to resort to the use of a series of short check dams or to a stone
lining rather than to use an impermeable concrete or asphalt
lining.
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Factors which limit the use of vegetated waterways include exces-
sive soil credibility, excessive slope, high water table (either
normal or perched), excessively droughty soils, and in remote
cases, excessive soil toxicity. Without resorting to severe and
costly structural measures, such as concrete, asphalt, or stone
linings, the problems of excessive soil erodibility and excessive
slope can be successfully handled in many cases by using a series
of check dams to flatten the gradient of the waterway and to dissipate
flow energy.
The problem of wet soil conditions due to a high water table can
often be resolved by using pipe underdrains. When excessively
droughty or toxic soil conditions are encountered, the problem
can be corrected by undercutting and backfilling or top dressing
with nontoxic, drought resistant soil. When this procedure is
undertaken, care should be taken to get a good bond between the
native soil and the placed soil and also to sufficiently compact the
placed soil.
c. Design of Grassed Waterways. Robust rooted grasses that
germinate quickly and grow rapidly are generally the best type of
vegetation for waterway stabilization. When properly maintained,
they form a dense rootmat and a dense uniform surface cover that
does not restrict the movement of water and benefits both surface
water infiltration and the transpiration loss of near surface ground-
water. To determine what types of grasses are most suitable for
a given locality and a given site condition, the local soil and water
conservation district, county agricultural agent, or university
extension service should be consulted.
In order to protect against channel erosion in grassed waterways,
consideration must be given to the following factors:
(1) The erodibility of the soil for the proposed slope
(2) The flow velocity limitation for the vegetation
selected
(3) The ability of the soil to support the selected
vegetation
(4) The flow resistance (vegetative retardance)
of the selected vegetation
(5) The method of vegetation establishment (sod
versus seed) required to accomodate the volume
and velocity of the design flow
In general, seeding is only performed in waterways where the
design flow velocity is four feet per second or less. Sodding is
generally performed in waterways when the design flow velocity
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is between four and seven feet per second or when seasonal con-
siderations rule out the use of seeding. The velocity requirements
indicated above are only for erosion resistant soils. If the soil is
erodible at these velocities, then structural measures will be
required in conjunction with the seeding or sodding.
d. Stabilization Measures for Grassed Waterways. Temporary
stabilization measures are required in seeded waterways and, in
many instances, in sodded waterways to protect against erosion
until the vegetation is firmly established.
One of the products in common use for temporary waterway sta-
bilization is jute netting (Appendix C). The jute netting (Figure 17)
is generally placed directly over the prepared seedbed and, when
properly anchored, minimizes soil erosion. Due to its thick,
fibrous composition, the jute also functions as a mulch.
,':/,
FIGURE 17. Jute netting being used in waterway stabilization
Several other types of erosion control nettings designed for use
in waterway stabilization are available on the market. They
include plastic, paper, and fiber glass nettings (Appendix C). Both
the plastic and the fiber glass nettings, have a longer service life
than jute netting; however, due to the dense structure of the indi-
vidual material strands used in forming the nettings, they do not
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function as a mulch. Therefore, plastic and fiber glass nettings
are used over a long fiber mulch such as straw or hay. They
are applied, however, in a similar manner to jute netting.
A common problem in the establishment of vegetation in waterways
using nettings and mulch is subsurface drainage, which in perme-
able, granular soils often causes piping and subsequent loss of soil
from beneath the mulch and netting. To prevent such an occurrence,
erosion checks (Appendix B) must be established across the water-
way and beneath the netting at various intervals along the channel.
For the temporary stabilization of sodded waterways where the
soil is granular and moderately to excessively permeable and the
design flow velocity is in excess of four feet per second, use of
plastic or fiber glass netting and erosion checks in addition to
the normal stakedown procedure is recommended.
3. Stabilization of Soil Slopes
Soil slopes include all denuded cut, fill, or natural soil slopes.
a. Slope Design Criteria. Man-made cut and fill slopes are
usually constructed with a grade of 0 to 50 percent (2:1).
In some instances, when soil and hydrological conditions are excep-
tionally good, the grade is extended up to approximately 67 percent
(1-1/2:1). For all practical purposes, however, vegetative and soil
stability factors and maintenance considerations rule out the use of a
grade steeper than 50 percent.
A 33 percent slope is considered to be the maximum slope upon
which maintenance equipment can reasonably operate.
Factors to be considered in selecting a grade for a particular
geologic condition include:
(1) Slope stability
(2) Soil erodibility
(3) Ability of soil to support vegetation
Slope stability falls within the realm of soil mechanics and involves
an analysis of a given slope condition to determine whether or not
land sliding will occur.
Soil erodibility is a function of the following factors:
(1) The quality of the vegetative cover
(2) The soil gradation and permeability
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(3) The degree of soil compaction
(4) Clay minerology (in the case of clayey soils)
(5) The grade of the slope
(6) The length of the slope
(7) The quantity of water collected by the slope
The erodibility of a slope increases as the length of slope increases
and also as the quantity of water collected by the slope increases.
The effect of these factors on soil erosion can be controlled with
the use of various types of diversions (Figure 18) such as terraces,
benches, top of cut ditches, temporary diversion dikes, and inter-
ceptor dikes (Appendix B). Benches and terraces are used to break
the length of cut and fill slopes and to collect runoff and carry it to
a safe disposal point.
pi-
• i«
FIGURE 18. Diversions being used to control downslope runoff
Diversion dikes are temporary berms of soil placed along the top
of cuts and fills or at intervals along graded natural slopes for the
purpose of diverting runoff away from the denuded slope. The
runoff is instead diverted to a stabilized disposal point, such as a
level spreader, temporary flexible downdrain, temporary sectional
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downdrain, or chutes and flumes (Appendix B). Diversion dikes
are utilized during the construction phase and, in the case of fills,
they are generally maintained until an adequate vegetative cover
is established. For cuts, the diversion dikes are commonly
replaced by top of cut diversion ditches.
Interceptor dikes (Appendix B) are constructed of well compacted
soil or crushed rock (filter berm) and are generally used along
graded rights-of-way.
Compaction of fills is a major factor in erosion control. Poor
compaction is an especially serious problem on small construction
projects in urban developments where compaction control is often
lacking.
To prevent this occurrence, the planner and the local construction
codes should specify the degree of compaction to be achieved on
all types of fills. Certainly it is not necessary to achieve 95 per-
cent compaction in fills which will not be supporting structural
loads or where some settlement will not affect adjacent structures.
However, as a minimum criterion for erosion and sediment control,
the upper one foot of all fills should be compacted to at least 85
percent of optimum.
Smoothly graded cut and fill slopes are attractive to the eye, but
they are not beneficial from the standpoints of erosion and sediment
control and the establishment of a vegetation cover. It is more
desirable to roughen the surface, since this procedure slows down
flow velocity and enhances water infiltration. To accomplish these
effects, the texture of the roughened surface should trend perpen-
dicular to the flow direction. Discing and light scarification
(Appendix D) will accomplish this effect. Where the slope is too
steep to allow vehicular traffic to travel parallel to the slope,
cleated dozers travelling up and down the slope can produce a
satisfactory texture on newly placed soil.
The gradation of the soil on the surface of a slope and the perme-
ability of this soil affect both the erodibility of the soil and its
ability to support vegetation. For example, many well-drained
silty sands are highly erodible and may be droughty. When the
soil exhibits either or both of these conditions, it will be necessary
to adjust the configuration of the slope to accomodate these
factors or to top dress the slope with an erosion and drought
resistant soil. As an alternate to top dressing, a suitable soil
can be mixed with the existing soil.
On all slopes where top dressing with suitable topsoil or other
soil occurs, it is essential that the dressing soil be firmly bonded
to the existing soil surface in order to prevent slippage downslope.
This bonding can be increased by scarification (Appendix D) of the
slope.
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The quality of the vegetative cover is not only a function of the
physically related characteristics of the soil, such as density,
permeability, and moisture holding capacity, but it is also a function
of the chemistry of the soil. The pH of the soil, the presence of
nutrients in the soil, and the presence of toxic elements in the
soil all affect the quality of the vegetative cover.
When the pH and nutrient levels of the soil are known, it is often
possible to adjust these conditions to their optimum value for the
vegetation to be utilized by the addition of lime, fertilizers, etc.
When vegetative conditions occur that cannot be modified, the
slope should be top dressed with a more suitable soil.
Seasonal factors also affect the quality of vegetation. Cool, moist
periods of the year, such as occur in the spring and fall in tem-
perate regions, are more favorable for seed germination and plant
growth than are the hot, dry summer months.
Different types of vegetation vary widely in their ability to tolerate
certain climatic conditions. To determine the best vegetation
for a climatic condition in a given region, the developer can
receive guidance from the local soil and water conservation districtj
the county agent, or university extension service.
In many parts of the country, quick growing annuals are planted as
temporary ground cover until climatic conditions are favorable for
the germination and growth of more desirable perennial grasses
and legumes.
b. Soil Stabilization Measures. Soil stabilization measures
include both short-term measures and long-term vegetative
measures and are utilized to control water and wind erosion during
and after grading operations.
Interim stabilization measures are used to retard erosion for a short
time period, such as over the winter months or through the hot
summer months, or until conditions are more favorable for long-
term vegetative stabilization. They include practices such as
mulching (Appendices A, C, and D) or the use of nettings, blankets,
etc. (Appendix C) with the seeding of annual grasses.
In addition to functioning as a short-term stabilization measure,
mulches, when applied during permanent seeding, also serve to
enhance the germination process by conserving moisture and to
dissipate the energy of falling raindrops.
Fiber mulches such as straw, hay, and woodchips (Appendix C)
as well as chemical soil binders (Appendix A), are commonly '
used to stabilize graded areas prior to seedinp to permanent
vegetation. The chemical soil binders (Appendix A) are de-
signed to penetrate and bind the near surface soil of to bind
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the surface of the soil. Chemical soil binders are used primarily
to protect denuded soil from wind and water erosion during delays
in grading operations and also during hot and dry periods, after
final grading, or until permanent seeding is possible.
Some chemical soil binders (Appendix A) also function as mulches,
i.e., they benefit the germination and growth of seeded vegetation
by conserving moisture in the soil and by providing temporary
protection against erosion.
In addition to the organic fiber mulches previously mentioned, a
fiber glass mulch (Appendix C) is also marketed for use in estab-
lishing vegetative cover.
The use of woodchips (Appendix C) for short term soil stabilization
and as a mulch is gaining greater prominence with the advent of
more restrictive burning and other disposal ordinances and as
bigger woodchippers are being built. Woodchips are found to be
one of the better mulches. They are long lasting and, due to their
weight and shape, they require little or no tacking to keep them
in place.
The use of large woodchippers for the disposal of all wood waste,
including all tree stems not salvageable for lumber, has consider-
able merit both from the standpoint of economics and erosion and
sediment control. The woodchips produced by the chippers can
be used for short-term stabilization and mulch on graded surfaces
and as a mulch for ground covers and woody plants. Any excess
woodchips can be placed as a four-inch-thick blanket in remaining
woodland areas where the natural leaf mulch has been disturbed by
construction activity.
With the exception of Glassroolr fiber glass mulch (Appendix C)
and, in some instances, woodchips, all organic and inorganic fiber
mulches require some form of attachment in order to prevent them
from being blown or washed away. Three methods are commonly
used to secure fiber mulches. The first method, crimping, is used
on straw and hay mulches and is performed by a crimping machine
which partially punches the mulch into the soil. The machine
operates and looks similar to a standard disc, except that the disc
blades on the mulch crimper are notched.
The second method of securing mulches is by tacking. This con-
sists of the application of an asphalt or chemical binder (Appendix A)
to the mulch (Figure 19) which binds the individual fibers together
to form a resistant blanket. Two" types of asphalt products are
commonly used. They include liquid asphalt (R. C. 1, 2 or M.C.
2 and 3) which can be applied in freezing weather and emulsified
asphalt (R.S. 1 and 2, M.S. 2, or S.S. 1) which cannot be applied
in freezing weather.
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FIGURE 19. Chemical mulch tack being applied
Rapid setting (R.S.) asphalt tacks are formulated for curing in
approximately 24 hours even during periods of high humidity.
Medium setting (M.S.) asphalt tacks are formulated for use in
spring and fall with approximately 24 hours curing time. Slow
setting (S.S.) asphalt tacks are formulated for use during hot, dry
weather and require approximately 24 hours curing time.
Chemical mulch tacks cure more rapidly than asphalt tacks. This
makes them particularly valuable around home construction where
tracking of asphalt tack would be a problem.
The third method of securing fiber mulches is through the use of
various nettings (Appendix C). Nettings used for this purpose
are constructed of jute, plastic, paper, and fiber glass. Jute and
paper nettings have a short life span and are biodegradable (Appendix C).
Nettings are normally only used on steep, exposed slopes where
crimping is not possible and where tacking will not perform
satisfactorily.
Several "blanket" type materials (Appendix C) are available for
use where natural or synthetic fiber mulches are not selected.
These "mulch blankets are most often used in establishing vege-
tation on swales, ditches, and steep slopes when it is decided that
40
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the fiber mulch products do not provide sufficient levels of pro-
tection during germination and early growth.
c. Sediment Retention Structures. Sediment retention structures
(Appendix B) are designed to remove sediment from runoff water.
The basic function of these structures is to still the runoff water
to such an extent that the sediment has time to settle out of suspen-
sion.
The most functional and desirable retention structure is the sediment
basin or pond which is installed along a natural or man-made water-
way. Sediment basins are normally thought of as short term struc-
tures, however, the larger basins may be utilized for
recreation purposes after development construction has been
completed. The size of a sediment basin is dependent upon the area
of its watershed, the topography of the watershed, the infiltration
rate of the soils in the watershed, and regional hydrological factors.
Most states have ordinances covering the design and construction
of all sizes of sediment basins. These ordinances must be reviewed
prior to designing the impoundment.
In almost all cases, the sediment basin is formed by an earthen
dam constructed across the waterway. In some cases, however,
the impoundment is formed by excavating a depression in the
waterway. This practice is generally utilized on small drainage
swales and around storm drain inlets during grading operations.
Other types of materials used in sediment retention structures
include straw bales, filter berms (Figure 20), and sandbags
(Appendix B). These materials are normally used on small jobs
where the runoff is small. On sloping lots, straw bales are often
used to divert sediment-laden runoff to sediment retention structures.
Crushed stone and sandbags (Appendix B) are often placed around
storm drain inlets to filter out sediment. Straw bales (Appendix B)
can also be used for this purpose, but care should be taken to keep
them from breaking apart and getting into the storm drain system.
Vegetative filter strips (Appendix D) are also used around storm
drain inlets to retard flow and filter out the sediment. Thick
growing, sturdy grasses should be used for this purpose.
F. Formulation of Erosion and Sediment Control Plan
In order to insure that the erosion and sediment control procedures
developed by the planner are implemented by the contractor, it is required
that a detailed erosion and sediment control plan be drawn up and included
with the other construction documents. The plan must be presented for
41
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FIGURE 20. Filter berm
review, approval, and certification to all cognizant agencies empowered
by sediment and erosion control legislation. A copy of the plan must be
continuously available on the job site. Figure 21 is an example of the
type of plan that is presently being prepared and used. The size of the
project, the intensity of the proposed development, and the land type will,
of course, influence the required complexity of the plan, but as a minimum
the following factors should be given consideration and included in the
documents.
1. Clearing and Grading Schedule
It is necessary that the contractor minimize the amount of land to be
exposed at any one time. This can be accomplished by developing the
site in stages and by requiring the performance of all clearing, grading,
and stabilization operations in a specified area before moving on to
another specified area. This procedure should be written into the
construction specifications and contract. Maps should be provided which
define each area. The sequence and scheduling in which development wil
occur must be well established and understood by all persons involved
with the development operation.
For ease of sediment control, it is usually desirable to define these
areas on the basis of watersheds or sub water sheds. The size of the
area should be determined on the basis of the construction capability
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Filter^
Inlet
Diversion
' Straw BaJe
Diversion
Diversion
IV >Ji
Filter -Bea
Emergency
Spjlfway'
Sediment
FIGURE 21. Example of a sediment and erosion control plan
43
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of the contractor and the amount of critical area, such as steep slopes
and areas of high soil erodibility, present in the watershed.
A factor which must be considered when scheduling areas to be developed
is the relationship of vegetative stabilization to climatic factors. In areas
having severe exposure problems or exhibiting severe erosional problems,
it is desirable to schedule the development so that it begins in a period
of low precipitation and is completed near the beginning of a period
favorable to the establishment of vegetation. This consideration should
also apply to woodland areas, where development during the dormant
winter months is more desirable from the standpoint of tree preservation.
Conversely, it is more desirable to develop areas adjacent to major flood-
plains during the growing season, since the natural vegetative filter strips
will be more functional at this time.
2. Location, Construction, and Maintenance of Sediment Retention
Structures
The same site maps which delineate the sequence of development must
also show the location of all sediment retention structures. The plan
documents must indicate the sequence of the construction of these
structures with relation to the specific areas. For example, it is
required that all sediment structures scheduled for natural waterways
in a development area be installed prior to the initiation of clearing
and grading operations. When the development area does not coincide
with the watershed boundaries, it may be necessary to also construct
sediment retention structures outside the limits of grading prior to
the start of construction.
Contracts and development plans should clearly indicate the contractor's
responsibilities for maintaining the sediment retention structures.
3. Traffic Control
This is a particularly important requirement in woodland developments
where uncontrolled traffic can cause severe tree damage (Appendix D).
Those areas, such as vegetative filter strips along waterways and all
undisturbed open spaces, must be delineated on a site map and designated
as "off limits" areas for all vehicular traffic (Appendix D).
For woodland areas, the specifications must state that all vehicular
traffic will stay within the roadway, access corridor, or utility rights-
of-way. These rights-of-way must also be shown on the site map.
The specification must also restrict all traffic from crossing streams or
stabilized drainageways except at approved stabilized crossing locations.
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4. Stream Erosion
All critical areas along streams must be marked on the site maps and
the recommended method of stabilization indicated. Stream stabilization
work should be scheduled for periods of low precipitation during the
growing season and should be performed prior to the initiation of clearing
and grading operations in the watershed.
5. Planting Schedule
The erosion and sediment control plan must clearly define vegetative
practices, both temporary and permanent. The plan must state and show
where and when sod, temporary seeding, and permanent seeding are to
be used. Specifications shall also be provided regarding ground prepa-
ration, sod quality, seed type and quality, fertilization, and mulching.
6. Grading Delays
The construction specifications must clearly define the maximum length
of time that a graded area can be left uncovered after completion of
grading and also after grading shut downs, such as commonly occur in
some areas during the winter months. The specifications must also
state what short-term stabilization practices will be performed in the
event of a lengthy grading delay.
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SECTION IV
OPERATIONS
A. General
Operations in these guidelines is that process by which sediment and
erosion control planning is implemented. It includes the survey and
stakeout that will guide all subsequent work. Clearing and rough grading
are generally the first steps in which major changes in surface landscape
configuration are accomplished. Utility main service construction follows
the rough grading and is, in turn, followed by the actual preparation of
and construction on building sites. The implementation of the sediment
and erosion control plan immediately precedes, is coincident with, or
immediately follows each of the operational steps listed above.
As designated on the erosion and sediment control plans, the installation
of major structures may be required before any other development work
can be accomplished. This is especially true in those cases where rather
large sediment retention basins (Appendix B) are required. If stream
channel stabilization is required, its construction may also be required
before actual site development can begin.
P. Roadway Construction
Clearing for roadway construction will have been planned in detail. In
the event that the site being developed is wooded, details regarding the
method of removal and ultimate disposition of trees will have been estab-
lished considering the legal aspects of the clearing operations, the salvage
of wood products (Appendix D), and the use of some of these products in
the implementation of sediment and erosion control practices (Appendix C).
It is in conjunction with the clearing of trees that the protection of those
trees selected for preservation must begin (Appendix D). The erection
of planned fences to protect trees, the work of concerned clearing crews
and heavy equipment operators, etc. , must all be demonstrated in this
phase of site development. Marketable timber will, of course, be removed.
Fireplace wood should be stacked or removed promptly for public or
private use. Woodchips generated on-site should be stockpiled for sub-
sequent use on the site being cleared, or should be removed for use on
other sites in the area that are being developed and at which the woodchips
can be used immediately (Appendix C).
Special attention should be given to the completion of the "extra" clearing
required for equipment travel corridors, especially along the top of cut
slopes (Appendix D).
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The advent of actual grading operations provides the first opportunity
to practice one of the principles of pound sediment and erosion control,
minimization of the area of disturbance. This usually involves traffic
control (Appendix D). Corridors for equipment travel should he estab-
lished across those areas that will not be immediately denuded, especially
in wooded areas. The natural filter strip areas (Appendix D) should be
given special attention. Disturbance of vegetated floodplains is also to
be avoided except when absolutely necessary. Instructions will have to
be issued that "routes for convenience" will not be allowed and that the
established equipment travel corridors are to be used. These instructions
must also be enforced.
Stockpile areas will have to be selected and their integrity maintained.
These stockpile areas should have been designated on the grading plan.
If not, their on-site selection must be tempered with sediment and erosion
control considerations, such as the direct production and delivery of
sediment to waterways, damage to vegetation that is part of the total
sediment and erosion control plan, and the unnecessary destruction of
trees that are selected for preservation. Temporary or interim stabili-
zation of soil stockpiles must be instituted (Appendix A). The existence
of critical slopes on stockpiles must be avoided, especially if the material
is easily eroded. Stockpiling in or immediately adjacent to watercourses
must not be allowed because the stockpiled material will provide a direct
and high volume source of sediment to storm runoff. If the stockpile(s)
is large, structural practices may be required (Appendix P). If they
are not incorporated into the site plan for sediment and erosion control,
their design and implementation must be accomplished by on-site personnel.
Temporary vegetative measures planned for implementation on major
stockpile areas should be established immediately after the stockpile
operation is completed. If the stockpile is large and stage implementation
of temporary vegetative cover has been planned, it should be promptly
established. Proper mulching and soil stabilization in conjunction with
these seeding operations should be carried out (Appendices A and D).
As the rough grading operations near completion, the installation of
structural and vegetative practices must be promptly accomplished.
Diversion dikes, interceptor dikes, filter berms, etc. (Appendix B),
should be constructed according to plan. The use of woodchips (Appen-
dix C) on cut and fill slopes should begin as soon as slopes become avail-
able to receive them. If chemical soil stabilization (Appendix A) has been
planned, it must be accomplished as soon as the slopes are completed.
The establishment of temporary vegetative cover should begin as soon as
slopes become available, not after the whole grading project has been
completed.
Although timely implementation of sediment and erosion control practices
has not been established as a distinct practice, its importance cannot be
overstressed. Each day that a potential sediment source remains unsta-
bilized is another day that it exists as a source of pollution.
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Drainageway protection, whether natural or man-made, must be an
integral part of the grading operations. There is no justification for
equipment travel in these watercourses. Traffic should not be allowed
to cross watercourses except at specified locations (Appendix D).
As the sediment and erosion control measures and practices established
to date begin to function, their maintenance must be initiated. Sediment
removal from structures designed to trap and filter must begin. Inspec-
tion of practices after each rain must become a reality. Replacement of
items like straw bales, woodchips, and seedbeds must be promptly accom-
plished in cases where they have been destroyed by a severe storm,
vandalism, or deterioration.
C. Underground Utility Construction
If a detailed plan of sediment and erosion control practices has been
prepared for implementation with the construction of utilities, it only
remains to "put them on the ground" as the work is completed. The
utility service construction must be well coordinated so that soil dis-
turbance will be minimal and all utility construction can be completed
in the shortest time possible.
From an erosion and sediment control standpoint the use of a trench for
more than one utility is desirable. So is the prompt backfilling and
compaction of soil in these utility trenches (Figure 22).
FIGURE 22. Erosion along an improperly backfilled utility trench
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If additional clearing is required for the construction of utilities, it
should be governed by the same considerations that have been previously
listed, and tree protection and the utilization of wood products generated
by clearing operations should follow the guidelines established in
Appendices C and D.
Since much utility construction associated with urban development is
installed in rights-of-way across private property, special care must
be exercised so that damage will not be caused to natural resources or
land immediately adjacent to these rights-of-way. The destruction of
tree feeder roots and protective vegetation must be avoided. They are
most often destroyed by cutting during excavation, burial by soil, or
compaction by heavy equipment. This cannot be avoided within the
construction right-of-way. It cannot be tolerated beyond the construction
right-of-way.
The construction of groundwater control devices, equipment travel, and
stockpiling of construction material beyond the right-of-way are the most
serious causes of vegetative destruction. These transgressions against
sound sediment and erosion control practice and private property can
only be prevented by a more scientific approach to utility construction.
Brute force techniques can no longer be tolerated.
Because flow in storm and sanitary sewer mains is maintained by gravity
in most cases, these services are often constructed parallel to drainage-
ways. For this reason, extra care during construction is required if the
rules of sound sediment and erosion control are to be maintained. Ex-
cavated material must be stockpiled on the side of the trench, away from
the stream channel. Flooding is less likely to remove the soil from the
site as sediment if this practice is followed.
If a stockpile is to remain for some period of time, it should be stabilized.
Soil stabilizing chemicals (Appendix A), temporary vegetation, interim
structures (Appendix B), or special practices (Appendix D) may be required.
Traffic must be strictly limited to rights-of-way or traffic corridors,
especially when construction is on or adjacent to streams and floodplains.
The filtering of sediment-laden runoff by the vegetation on floodplains is
an important measure in the reduction of sediment delivered to downstream
areas and it must be preserved. Indiscriminate and "convenience" travel
cannot be tolerated if this natural filter (Appendix D) is to continue to
perform.
Pumped water management (Appendix D) is a practice that the utility
contractor can use to reduce the production of sediment. In the past,
most people did not consider this routine construction operation as a
source of sediment pollution. The simple act of discharging pumped
water onto a stabilized area is a practice that can be implemented at
little or no extra cost. If ditches are required to remove water pumped
from construction excavations, they must be given the same consideration
as any other man-made waterway. They must be stabilized if they are
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not to degrade and produce sediment. Erosion and sediment control
structures (Appendix B) may be required to accomplish this stabilization.
After construction in this phase of the development activity is complete,
vegetation on the areas that have been disturbed must be reestablished.
If permanent vegetation is planned, it must be established as rapidly as
possible. If the completion of the construction activities does not coin-
cide with a season in which permanent vegetation can be started, an
interim or temporary program is required. This can include soil stabili-
zation (Appendix A), mulching (Appendix D), or the establishment of
filter strips or the use of scarification (Appendix D). In any case, sedi-
ment and erosion controls must be installed promptly and their maintenance
must be assured.
D. Building Construction
As construction begins, the implementation of that part of the sediment
and erosion control program scheduled for this segment of the develop-
ment activities will also get underway. On wooded lots, the first task
to be accomplished is the marking of the trees that are to be preserved.
Fencing is recommended if the trees marked for protection are to be
given the maximum possible protection. As indicated elsewhere
in this document, concern for trees is desirable both from an aesthetic
as well as from a sediment and erosion control point. Trees do protect
the soil. Where required, the removal of trees can be accomplished in
a manner that is acceptable from an environmental standpoint and from
an operations standpoint.
As the lot takes its final physical shape, tree preservation activities
(Appendix D) will have to begin. The disposal of the wood products
generated during the clearing operation should follow the recommenda-
tions of Appendices C and D. Lumber can be marketed. Fireplace
wood can be reserved for use in neighborhood housing (Figure 23).
Woodchips should be returned to the lot as part of the erosion control
plan (Figure 24). Stumps should be removed by stump cutting (Appendix
D) rather than dozing.
If homes are being constructed with basements, the problems associated
with basement excavation must be resolved. Access to the excavation
must be closely controlled. The access ramp must be constructed in
such a manner that remaining trees are not damaged. The material
removed from the basement excavation must be selectively stockpiled
in areas where a minimum of sediment will be generated and where
other damage will not result from the piled earth (Figure 25). Natural
drainageways must be protected at all times and piling soil excavated
from a basement in a drainageway cannot be tolerated.
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FIGURE 23. Firewood produced during clearing operations
FIGURE 24. Use of woodchips as an interim erosion control
practice on a homesite
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FIGURE 25. Selective stockpiling to protect trees
Construction of basement structures should begin as soon as the excava-
tion is complete so that backfilling or other disposition of the unstabilized
soil can be promptly accomplished. If stockpiles are to remain for some
time, they should be stabilized (Appendix A) or sufficient protection should
be provided by other means (filter strips - Appendix D; mulching -
Appendix C) to insure that they do not produce sediment for removal
and delivery to downstream sites.
Short term site stabilization can begin as soon as the basement spoil has
been spread and/or removed from the site and the final surface configura-
tion is complete. Temporary seeding and mulching (Appendix C), soil
stabilization with chemicals (Appendix A), and woodchips (Appendix C)
can all be used to advantage. In areas that are subject to foot or wheeled
vehicle traffic, a four-inch layer of woodchips will provide the best method
of protection.
Traffic on the lot should be kept to an absolute minimum. Delivery of
material will, of course, be required. This traffic should enter and leave
on a designated access route. Stockpiling locations should be carefully
selected so that sediment and erosion control practices are not destroyed
(Figure 26). Passenger vehicle traffic should be discouraged. Workmen
should walk from the street rather than drive and park on stabilized areas.
Early completion of the access drive(s) will provide a stabilized route for
light vehicle traffic and this practice is encouraged.
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..
FIGURE 26. Stockpile with a natural filter strip located downslope
When construction is complete, final grading for landscaping purposes
will begin. Again, tree protection will have to be a principal concern.
The concern is now one of tree preservation for ultimate use and enjoy-
ment by the new owner. It is no less important, however, that the tree
preservation notations (Appendix D) be considered to insure that
no damage is incurred at this late date, because trees damaged during
this stage of the operations phase of development will directly affect the
reputation of the builder. With this in mind, items such as filling over
tree root systems or cutting feeder roots take on great importance.
The only task remaining after final grading is complete is the establish-
ment of permanent ground cover. This stage should begin by collecting
representative surface soil samples for testing, analysis, and nutrient
recommendations. This is especially true in areas that have been filled
since the fill soil has probably not been tested and its deficiencies will
have to be determined if a good vegetative stand is to be established.
Guidance for soil sample collection and testing can be obtained from the
county extension agent.
While results of soil testing are pending, the plans for the care and feeding
of trees on wooded lots can be started. Individuals should seek guidance
from the state and federal forest services or professional silvaculturists.
This effort is important since the original woodland environment has been
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changed to a parkland environment and this change can adversely affect
trees that remain.
Sod is often placed to quickly establish cover on a prepared surface.
This surface should be prepared as if it were to be seeded if optimum
results are to be realized. The recommendations resulting from soil
sample testing should be followed. Turf establishment by sodding can
be accomplished at any season except winter in the temperate climate.
If seeding is selected as the method of establishing turf, the soil sample
testing recommendations should be incorporated into the preparation of
the seedbed. Mulching of the seeded area (Appendices AandC) will greatly
enhance the germination and growth of a good stand. If long fiber mulch
is selected, it should be securely tacked (Appendix A) or anchored in
place by mechanical methods (Appendix D) or nettings (Appendix C).
In the event that final lot grading is completed in a season that is not
compatible with the establishment of permanent vegetative cover,
temporary practices should be used to stabilize the soil until a satis-
factory seeding, germination, and growth season arrives. Chemical
soil stabilizers (Appendix A), the use of temporary vegetation such as
quick growing annual grasses, and mulching (Appendix C) can all be used
to effect temporary control of erosion and sediment production.
Areas of concentrated runoff, i. e., drip lines, downspouts, etc., will
require additional effort if they are not to adversely affect attempts to
establish vegetative cover (Figures 27 and 28). The use of mulch and/or
mulch blankets under driplines (Appendix C) will dissipate the energy of
falling water and allow the growth of new seed. Discharge to splash
blocks, dry wells, and the removal of water from downspouts to stabilized
areas by conduit should all be considered when providing protection to
newly seeded areas.
When the final ground cover has been established, the development of the
site is complete and the satisfaction of a job well done can be enjoyed.
If the development has been completed in a manner that is consistent with
good environmental control through the implementation of a sound sedi-
ment and erosion control plan, the satisfaction gained can be even greater.
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FIGURE 27. Erosion at an unprotected dripline
1 ,. !
-
,«•—„"-_ «{•»•
JWrT"
FIGURE 28. Dripline protection with a fiber glass blanket
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SECTION V
MAINTENANCE
Maintenance regarding sediment and erosion control is an area that has
received little more than lip service in the past. Practices are installed
but little thought has been given to maintaining them in a condition that
allows them to function properly.
Heavy equipment is greased and lubricants are changed regularly in an
effort to get optimum equipment performance. Repairs are kept to a
minimum if lubrication and other maintenance schedules are carried
out. Similarly, sediment and erosion control practices will not function
properly throughout their designed life span if they are not maintained.
Whether the practice is vegetative or structural, minimum maintenance
schedules must be implemented if the practices are to continue to function
in the control of erosion and sediment pollution.
The most important maintenance practice is the timely cleanout and stable
disposition of trapped sediment from sediment retention basins. Many
areas have specially established criteria or schedules that provide guidance
as to when a basin should be cleaned. A rule of thumb that can be used is
to clean out a basin when it has lost 50 percent of its storage capacity due
to sediment deposition. Filling to depths greater than half greatly reduces
the capacity of the basin to retain runoff long enough for sediment to be
deposited before it moves downstream.
The sediment removal operation must also consider the stable disposition
of the soil removed from the basin. Indiscriminate piling or dumping is
unacceptable because the sediment is likely to be moved back into the
storm drainage system by successive storm events. When this is the case,
the material is again a pollutant.
Disposition behind a protective berm or filter strip will often suffice if
the quantities involved are not large and can be affected by dragline and
truck transport. In basins with larger capacities, the services of pro-
fessionals experienced in the handling and disposition of sediment should
be retained.
Appendix B contains a brief description of the minimum maintenance
required for each of the various structural practices. Many require
work to restore them after each storm. Where this is the case, nothing
short of compliance will suffice if the structure is to continue to function.
Responsibility for maintenance must be formally assigned on a develop-
ment site of any size. It must be assigned to an individual who is know-
ledgeable in maintenance requirements and who has access to equipment,
material, and funds required to sustain the maintenance schedule. In-
formal implementation of structural maintenance results in no maintenance.
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Several of the practices incorporated into the appendices cannot survive
if they are subjected to foot or vehicle traffic. In areas where these
practices are installed, the prohibition of traffic must be maintained.
This can only be accomplished by an information distribution program
that "spreads the word' to all persons working in the area.
Vegetative practices require maintenance in two general areas. The
first is periodic refertilization. Too often a stand of vegetative cover
established in the sediment and erosion control program is allowed to
deteriorate and become ineffective because it is nutritionally starved.
A fertilization maintenance program should be established and carried
out as the development of the area proceeds.
Areas where failures have been experienced in the establishment of
vegetative protection must be promptly treated. If the failure is due
to rilling or gully formation, temporary structural practices such as
flexible downdrains and section slope drains (Appendix B) can be
utilized while arrangements for permanent control are made. The re-
establishment of permanent vegetative cover should be the ultimate
goal. However, changed site conditions may require the installation of
some sort of permanent structural control like level spreaders, diver-
sions, etc. (Appendix B). Any remedial treatment should be initiated
as soon as possible in an effort to keep the area requiring maintenance
work to a minimum. Timely maintenance will also reduce costs in the
long run.
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SECTION VI
ACKNOWLEDGEME NTS
These guidelines were prepared under the joint sponsorship of the U. S.
Environmental Protection Agency and the Maryland Department of Water
Resources by Hittman Associates, Inc. , of Columbia, Maryland. Sin-
cere thanks are extended to Mr. Ernst Hall, Chief, Pollution Control
Analysis Section, EPA; Mr. John J. Mulhern, Project Manager, EPA;
and Dr. H. R. Thacker, Project Officer, EPA, for their support and
guidance throughout the period of basic data acquisition and document
preparation.
Special guidance was provided by Mr. Marshall T. Augustine, Sedimen-
tation Specialist, Maryland Department of Water Resources, and his
participation and assistance in the preparation of this document is
gratefully acknowledged. The editorial comment and support of Mr.
Albert E. Sanderson, Jr., Coordinator for Research, Maryland Depart-
ment of Water Resources, is acknowledged with sincere thanks.
The contributions provided to this program by the Howard Research
and Development Corporation, the developers of Columbia, Maryland,
and the Columbia Parks and Recreation Association, Inc., are also
gratefully acknowledged.
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SECTION VII
REFERENCES
1. Fairfax County, Virginia, Erosion-Siltation Control Handbook (draft)
July 1971.
2. Soil Conservation Society of America, "Resource Conservation
Glossary, " Journal of Soil and and Water Conservation, Vol. 25,
No. 1, January-February 1970.
3. State of California, Department of Public Works, Division of
Highways, Bank and Shore Protection in California Highway
Practice, November 1970.
4. U.S. Department of Agriculture, Soil Conservation Service,
College Park, Maryland, Standards and Specifications for Soil
Erosion and Sediment Control in Urbanizing Areas, 1969'.
5. U.S. Department of Transportation, Federal Highway Administration,
Bureau of Public Roads, "Use of Riprap for Bank Protection, "
Hydraulic Engineering Circular No. 11, June 1967.
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SECTION VIII
GLOSSARY
A.A.S.H.O. - American Association of State Highway Officials.
Abrasion - The wearing away by friction, the chief agents being currents
of water or wind laden with sand and other rock debris and
glaciers.
Abutment - The point of contact between the support and the thing
supported.
Acid soil - A soil with a preponderance of hydrogen ions, and probably
of aluminum in proportion to hydroxyl ions. Specifically, soil
with a pH value less than 7. 0. For most practical purposes, a
soil with a pH value less than 6. 6. The pH values obtained vary
greatly with the method used; consequently, there is no unanimous
agreement on what constitutes an acid soil. The term is usually
applied to the surface layer or to the root zone unless specified
otherwise.
Adverse - Hostile; unfavorable; harmful.
AEROSPRAY® 52 BINDER - See Appendix A, p. 81
Aesthetic - Of beauty; beautiful.
Air entraining - Air trapping; holding unusual quantities of air in
a mixture.
Annual plant (annuals) - A plant that completes its life cycle and dies
in 1 year or less.
AQUATAIN - See Appendix A, p. 83
Articulate - To joint; jointed.
Assess - Set a rate; to set the amount of (damages, a fine, etc.).
Available water-holding capacity - The capacity to store water available
for use by plants, usually expressed in linear depths of water per
unit depth of soil. Commonly defined as the difference between the
percentage of soil water at field capacity and the percentage at
wilting point. This difference multiplied by the bulk density and
divided by 100 gives a value in surface inches of water per inch
depth of soil.
Bedrock - The more or less solid rock in place either on or beneath
the surface of the earth. It may be soft or hard and have a smooth
or irregular surface.
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Berm - A shelf that breaks the continuity of a slope.
Channel - A natural stream that conveys water; a ditch or channel
excavated for the flow of water.
CHECK DAM - See Appendix B, p. 98
CHUTES - See Appendix B, p. 101
Clay - 1: A mineral soil separate consisting of particles less than
0.002 millimeter in equivalent diameter. 2: A soil textural
class. 3: (engineering) A fine-grained soil that has a high
plasticity index in relation to the liquid limits.
Clear cut - The removal of the entire timber stand on the area cut.
Contrast with selective cutting.
Coherent - Sticking together; having cohesion.
Cohesive - Holding together - Force holding a solid or liquid together,
owing to attraction between like molecules.
Coincide - To take up the same place in space; be exactly alike in
shape, position, and area; to occur at the same time; take up
the same period of time. To agree; be identical.
Colloid, soil - Colloid refers to organic or inorganic matter having very
small particle size and a correspondingly large surface area per
unit of mass. Most colloidal particles are too small to be seen
with the ordinary compound microscope.
Compaction - To unite firmly; the act or process of becoming compact,
usually applied in geology to the changing of loose sediments into
hard, firm rock. With respect to construction work with soils,
engineering compaction is any process by which the soil grains
are rearranged to decrease void space and bring them into closer
contact with one another, thereby increasing the weight of solid
material per cubic foot.
Compatible - Capable of existing together; in agreement.
Competent rock - Beds or strata which, because of massiveness or
inherent strength, are able to withstand great pressure or stress;
hard.
Conduit - Any channel intended for the conveyance of water, whether
open or closed.
Configuration - Arrangement of parts; outline.
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Conservation - The protection, improvement,and use of natural resources
according to principles that will assure their highest economic and
social benefits.
CONSTRUCTION COORDINATION - See Appendix D, p. 194
Contour - 1: An imaginary line on the surface of the earth connecting
points of the same elevation. 2: A line drawn on a map connecting
points of the same elevation.
Contour interval - The vertical distance between contour lines.
Convenience - A condition personally favorable or suitable; advantage;
handy.
Cool season plant - A plant that makes its major growth during the cool
portion of the year, primarily in the spring but in some localities
in the winter.
Coordinate - To bring into proper order or relation; harmonize; adjust;
function harmoniously.
®CURASOL AE - See Appendix A, p. 85
®CURASOL AH - See Appendix A, p. 87
DCA-70 - See Appendix A, p. 89
Deciduous plant - A plant that sheds all its leaves every year at a
certain season.
Deficiency - The amount by which a series of quantities falls short of
a given demand, normal, or other criterion; opposite of excess.
Deleterious - Harmful to health, well being; injurious.
Delineation - A drawing; sketch; description.
Density - Mass or quantity per unit of volume, close; compact.
Denuded - Bare; naked; stripped.
Detention practice - Practice or structure installed for the purpose of
temporary storage of stream flow or runoff and for releasing the
stored water at controlled rates.
Discharge - Rate of flow, specifically fluid flow; a volume of fluid passing
a point per unit time commonly expressed as cubic feet per second,
million gallons per day, gallons per minute, or cubic meters per
second.
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Dissipate - To scatter; disperse, cause to vanish.
Diversion - Channel constructed across the slope for the purpose of
intercepting surface runoff; changing the accustomed course of
all or part of a stream.
DIVERSION DIKE - See Appendix B, p. 105
Dolomitic - Of or pertaining to dolomite - a sedimentary rock
of magnesium and calcium carbonate.
Downcutting - When the debris supplied to a stream is less than its
capacity for carrying loads, the stream abrades (erodes) its bed and
is said to be a downcutting stream.
Drainage basin - All land and-water within the confines of a drainage
divide.
Drainage pattern - The configuration or arrangement of streams within
a drainage basin or other area.
Drip line - An imaginary line on the ground surface that corresponds to
the farthest lateral extension of the branches of a tree. The area
where water falling from a roof strikes the ground.
Droughty - Exhibiting a poor moisture-holding capacity due to excessively
high permeability and a low percentage of fines.
Duff - The more or less firm organic layer on top of mineral soil,
consisting of fallen vegetative matter in the process of decomposition,
including everything from pure humus below to the litter on the
surface. Duff is a general, nonspecific term.
Ecology - The study of the interrelationships of organisms to one another
and to the environment.
Empirical - Relying or based solely on experiment and observation.
Enhance - To make greater, as in cost, value, effectiveness. To increase.
Environment - The sum total of all the external conditions that may act
upon an organism or community to influence its development or
existence.
Erodible - Susceptible to erosion.
Erosion - 1: The wearing away of the land surface by running water, wind,
ice, or other geological agents, including such processes as
gravitational creep. 2: Detachment and movement of soil or rock
fragments by water, wind, ice, or gravity.
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EROSION CHECK - See Appendix B, p. 109
Evaporation - The process by which a liquid is changed to a vapor or gas.
EXCELSIOR BLANKET - See Appendix C, p. 164
Expansive - Tending to expand; that can expand.
Expedient - Convenient; suited to the circumstances or the occasion.
FABRIFORM® - See Appendix B, p. 114
Fertility - The quality of a soil that enables it to provide nutrients in
adequate amounts and in proper balance for the growth of specified
plants when other growth factors, such as light, moisture,
temperature, and the physical condition of the soil,are favorable.
FIBER GLASS MATTING - See Appendix C, p. 167
Fibrous root system - A plant root system having a large number of
small, finely divided, widely spreading roots but no large individual
roots. Typified by grass root system. Contrast with taproot system.
FILTER BERM - See Appendix B, p. 119
FILTER INLET - See Appendix B, p. 123
Filter strip - Strip of vegetation that retards flow of runoff water,
causing deposition of transported material, thereby
reducing sediment flow.
Fines - Silt and clay sized. Soil particles less than 0.074 mm
(#200 sieve) in diameter.
FLEXIBLE DOWNDRAIN - See Appendix B, p. 128
Floodplain - Nearly level land situated on either side of channel which
is subject to overflow flooding.
FLUME - See Appendix B, p. 101
Flush - Even or level.
GABIONS - See Appendix B, p. 132
Geology - The science of the earth.
Germination - Sprouting; beginning of growth.
Grommet - A metal eyelet in fabric.
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GLASSROOT® - See Appendix C, p. 169
Gradation - The frequency distribution of the various sized grains that
constitute sediment, soil, or other material.
Grade control structure - A mechanical device or structure used to
control the slope of a channel.
Gradient - Change of elevation, velocity, pressure, or other characteris-
tics per unit length; slope.
Grain size gradation - The gradation of soil particles.
Groin - A shore-protection and improvement structure. It is narrow
in width compared to its length.
Groundwater - Phreatic water or subsurface water in the zone of saturation.
Grouted - Having the area between pieces of rock, brick, etc., filled
with mortar or concrete.
Gully - A channel or miniature valley cut by concentrated runoff but
through which water commonly flows only during and immediately
after heavy rains or during the melting of snow. A gully may
be dendritic or branching or it may be linear, rather long, narrow,
and of uniform width. The distinction between gully and rill is
one of depth. A gully is sufficiently deep that it would not be
obliterated by normal tillage operations, whereas a rill is of lesser
depth and would be smoothed by ordinary farm tillage.
Habitat - The environment in which the life needs of a plant or animal
are supplied.
HAY - See Appendix C, p. 183
Herbaceous - Of any flowering plant except those developing persistent
woody bases and stems above ground.
Hydraulic - Operated by the movement and force of liquid.
Hydrology - The science of water, its properties, laws, and distribution.
Impoundment - An enclosed body of water, usually man-made.
Inconsistent - Not uniform; not holding to the same principles or practice.
Indiscriminate - Confused; random, making no distinctions.
Indurated - Rendered hard; hardened by heat, pressure, or cementation.
Soil material rendered into a hard mass that will not soften on
wetting.
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Inferred - Concluded or decided from something known or assumed;
derived by reasoning; drawn as a conclusion.
Infiltration - The flow of a liquid into a substance through pores or
other openings, connoting flow into a soil in contradistinction to
the word percolation which connotes flow through a porous substance.
Informal - Not formal; casual; easy.
Inhibit - To holdback, restrain, curb; to prohibit; forbid, to suppress.
Insolation - The radiation from the sun received by the earth's surface.
Integral - Necessary for completeness; essential, complete.
Integration - Making whole or complete by adding or bringing together
parts, unify.
Integrity - The quality or state of being complete; unbroken condition;
wholeness; entirety.
INTERCEPTOR DIKE - See Appendix B, p. 136
Interface - A surface that lies between two parts of matter or space
and forms their common boundary.
Interim - Temporary; provisional.
Intermittent stream - A stream or portion of a stream that flows only
in direct response to precipitation. It receives little or no water
from springs and no long-continued supply from melting snow or
other sources. It is dry for a large part of the year, ordinarily
more than 3 months.
JUTE NETTING - See Appendix C, p. 172
Lateral - Of, at, from or toward the side; sideways.
Legume - A member of the legume or pulse family, Leguminosae.
One of the most important and widely distributed plant families.
The fruit is a "legume" or pod that opens along two sutures when
ripe. Flowers are usually papilionaceous (butterflylike). Leaves
are alternate, have stipules, and are usually compound. Includes
many valuable food and forage species, such as the peas, beans,
peanuts, clovers, alfalfas, sweet clovers, lespedezas, vetches,
and kudzu. Practically all legumes are nitrogen-fixing plants.
Levee - An embankment to confine or control water, especially one built
along the banks of a river to prevent overflow of lowlands.
LEVEL SPREADER - See Appendix B, p. 140
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LIQUID ASPHALT - See Appendix A, p. 91
Maintenance - Upkeep; support.
Meander - One of a series of somewhat regular and looplike bends in the
course of a stream.
Migration - The movement from one place to another.
Moisture-density relationship - The relationship in a soil between its
moisture content and its density at that moisture content.
Monolithic - Massively solid, single, and uniform.
Mottled - Soil horizons irregularly marked with spots of color. A common
cause of mottling is impeded drainage, although there are other
causes, such as soil development from an unevenly weathered
rock. The weathering of different kinds of minerals may cause
mottling.
Mulch - A natural or artificial layer of plant residue or other materials,
such as sand or paper, on the soil surface.
MULCH ANCHORING - See Appendix D, p. 195
MULCH BLANKET - See Appendix C, p. 176
NETTING - See Appendix C, p. 179
Nonphytotoxic - Not poisonous to plants.
Nontoxic - Not poisonous.
Ordinance - A statute (law) enacted by the legislative department of
a government.
Organic matter - The organic fraction of the soil that includes plant and
animal residues at various stages of decomposition, cells and
tissues of soil organisms, and substances synthesized by the soil
population. Commonly determined as the amount of organic material
contained in a soil sample passed through a 2-millimeter sieve.
Oriented - Shown or established relationship with others by being placed
or arranged in a certain manner.
Orthophotograph - An aerial photograph from which all distortion due
to tip, tilt, and parallax has been removed. An aerial photograph
from which or upon which accurate horizontal measurements can
be made.
Outcrop - To come to or be exposed on the surface.
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Outfall - Point where water flows from a conduit, stream, or drain.
Overfall - Aprupt change in stream channel elevation; the part of a dam
or weir over which the water flows.
Parkland environment - A formerly wooded area from which certain
trees have been removed and into which man-made structures or
buildings have been introduced.
Perched watertable - The surface of a local zone of saturation held
above the main body of groundwater by an impermeable layer or
stratum usually clay, and separated from the main body of ground-
water by an unsaturated zone.
Permanent stream - A stream that carries water throughout the year.
Permeable - Having a texture that permits water to move through it.
Permeability - The quality of a soil horizon that enables water or air to
move through it. The permeability of a soil may be limited by
the presence of one nearly impermeable horizon even though
the others are permeable.
Perspective - A proper evaluation with proportional importance given
to the component parts.
PETROSET®SB - See Appendix A, p. 93
pH - A numerical measure of the acidity or hydrogen ion activity of
a soil. The neutral point is pH 7. 0. All pH values below 7. 0 are
acid and all above 7. 0 are alkaline.
Phase development - Development by distinct and separate units.
Photo mosaic - A picture formed by matching together parts of a number
of overlapping vertical aerial photographs.
Piling - A long, heavy timber or beam driven or placed in the ground to
support a structure.
Piping - Removal of soil material through subsurface flow channels
or "pipes" developed by seepage water.
PLASTIC FILTER SHEET - See Appendix C, p. 182
Pollutant - Something that pollutes.
Pollute - Impair the purity of.
Porous - Containing voids, pores, interstices, or other openings
which may or may not interconnect.
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Prohibition - An order or law forbidding something to be done.
PUMPED WATER MANAGEMENT - See Appendix D, p. 196
Quadrangle The area of land charted on each of the atlas sheets
published by the United State Geological Survey.
Ratio - A fixed relation in degree, number, etc., between two similar
things; proportion. The quotient of one quantity divided by another
of the same kind, and usually expressed as a fraction.
Reconnaissance - A general examination or survey of a region with
reference to its main features, usually as a preliminary to a more
detailed survey.
Rejuvenate - To render young again. To renew erosive activity.
Remedial - Providing, or intended to provide, a remedy.
Remedy - Something that corrects; relief.
Revetment - Facing of stone or other material, either permanent or
temporary, placed along the edge of a stream to stabilize the
bank and to protect it from the erosive action of the stream.
Right-of-way - Right of passage, as over another's property.
A route that is lawful to use. A strip of land acquired for transport
or utility construction.
Rill - A small, intermittent water course with steep sides, usually only
a few inches deep and, hence, no obstacle to tillage operations.
Riprap - Broken rock, cobbles, or boulders placed on earth surfaces,
such as the face of a dam or the bank of a stream, for protection
against the action of water (waves); also applied to brush or pole
mattresses, or brush and stone, or other similar materials used
for soil erosion control.
Rootmat - A dense or thick concentration of the roots of vegetation.
ROUGHNESS - See Appendix D, p. 199
Runoff = That portion of the precipitation on a drainage area that is
discharged from the area in stream channels. Types include
surface runoff, groundwater runoff, or seepage.
Sand - A soil particle between 0.074 (#200 sieve) and 4.76 (#4 sieve)
millimeters in diameter.
SANDBAG SEDIMENT BARRIER - See Appendix B, p. 142
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Scarification - To loosen or stir the topsoil without turning it over as
with a plow or shovel.
SCARIFICATION - See Appendix D, p. 199
SECTIONAL DOWNDRAIN - See Appendix B, p. 145
Sedge - Any of several coarse, grasslike plants usually growing in
tufts or clumps in wet ground.
Sediment - Solid material, both mineral and organic, that is in
suspension, is being transported, or has been moved from its
site of origin by air, water, gravity, or ice and has come to rest
on the earth's surface either above or below sea level.
Sedimentation - The depositing of sediment.
SEDIMENT RETENTION BASIN - See Appendix B, p. 148
Seedbed - The soil prepared by natural or artificial means to promote
the germination of seed and the growth of seedlings.
Sheet flow - Water, usually storm runoff, flowing in a thin layer over
the ground surface.
Shrink-swell potential - Susceptibility to volume change due to loss or
gain in moisture content.
Silt - Soil particles between 0.074 millimeter (#200 sieve) and 0.002
millimeter in equivalent diameter.
Silviculture - Forestry.
Slaking - The crumbling or disintegration of earth materials when exposed
to air or moisture.
Slough - Come off; fall away.
Soil - 1: The unconsolidated mineral and organic material on the
immediate surface of the earth that serves as a natural medium for
the growth of land plants. 2: The unconsolidated mineral matter
on the surface of the earth that has been subjected to and influenced
by genetic and environmental factors of parent material, climate
( including moisture and temperature effects), macro- and micro-
organisms, and topography, all acting over a period of time and
producing a product-soil-that differs from the material from which
it is derived in many physical, chemical, biological, and
morphological properties and characteristics. 3: A kind of soil
is the collection of soils that are alike in specified combinations
of characteristics. Kinds of soil are given names in the system of
soil classification. The terms "the soil" and "soil" are collective
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terms used for all soils, equivalent to the word "vegetation"
for all plants.
Soil horizon - A layer of soil or soil material approximately parallel to
the land surface and differing from adjacent genetically related
layers in physical, chemical, and biological properties or
characteristics, such as color, structure, texture, consistence,
kinds and numbers of organisms present, degree of acidity or
alkalinity, etc.
Soil structure - The combination or arrangement of primary soil particles
into secondary particles, units, or peds. The secondary units
are characterized and classified on the basis of size, shape, and
degree of distinctness into classes, types, and grades, respectively.
Sprig - To plant a portion of the stem and root of grass.
Stage implementation - To accomplish by period, level, or degree.
Staged - By period, level, or degree.
Stereoscope - An instrument that gives a three-dimensional effect to
photographs viewed through it.
STRAW - See Appendix C, p. 183
STRAWBALE SEDIMENT BARRIER - See Appendix B, p. 159
Stress - Strain; pressure; especially a force exerted upon a thing that
tends to strain or deform its shape or well-being.
STUMP REMOVAL - See Appendix D, p. 203
Subwatershed - A watershed subdivision of unspecified size that forms
a convenient natural unit.
Swale - A hollow or depression.
Tacking (mulch) - The process of binding mulch fibers together by
the addition of a sprayed chemical compound.
Tangential - Touching, turned aside from a straight course.
Technology - Applied science.
Tenacity - Firmness of hold, cohesiveness, adhesiveness, or persistence.
TERRA TACK - See Appendix A, p. 95
Terrace - An embankment or combination of an embankment and channel
constructed across a slope to control erosion by diverting or
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storing surface runoff instead of permitting it to flow uninterrupted
down the slope. Terraces or terrace systems may be classified
by their alignment, gradient, outlet, and cross-section. Alignment
is parallel or nonparallel. Gradient may be level, uniformly graded,
or variably graded. Grade is often incorporated to permit paral-
leling the terraces. Outlets may be soil infiltration only, vegetated
waterways, tile outlets, or combinations of these. Cross-sections
may be narrow base, broad base, bench, steep backslope, flat
channel, or channel.
Tetrahedron - A solid figure with four triangular surfaces.
Timely - Well timed; opportune.
TRAFFIC CONTROL - See Appendix D, p. 206
Transition - Passing from one condition or form to another.
Trap efficiency - The capability of a reservoir to trap sediment.
TREE PROTECTION - See Appendix D, p. 211
Unified Soil Classification System - A classification system based on the
identification of soils according to their particle size, gradation,
plasticity index, and liquid limit.
Uplift - The upward pressure of water on the base of a structure.
Utilidor - A conduit, trench, tunnel, etc., that is used by more than
one utility or service.
VEGETATIVE FILTER STRIP - See Appendix D, p. 218
Warm season plant - A plant that completes most of its growth during
the warm portion of the year, generally late spring and summer.
Water table - The upper surface of groundwater or that level below
which the soil is saturated with water; locus of points in soil
water at which the hydraulic pressure is equal to atmospheric
pressure.
Watershed - All the land and water within the confines of a drainage
divide.
Waterway - A natural course or constructed channel for the flow of
water.
Well drained - Allows water movement readily but not rapidly.
Well graded soil - A soil in which a continuous distribution of grain
sizes from the coarsest to the finest components exist in such
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proportions that the successively smaller grains just fill in the
spaces between the larger grains.
Woodchipper - A machine that uses cutting devices to reduce wood to
small chips.
WOODCHIPS See Appendix C, p. 186
WOODFIBER MULCH - See Appendix C, p. 190
WOODLAND CLEARING AND EXCAVATION - See Appendix D, p. 222
Woodland environment - Any land used primarily for growing trees and
shrubs. Woodland includes, in addition to what is ordinarily
termed "forest" or "forest plantations, " shelterbelts, windbreaks,
wide hedgerows containing woodland species for wildlife food or
cover, stream and other banks with woodland cover, etc. It also
includes farmland and other lands on cover, etc. It also includes
farmland and other lands on which woody vegetation is to be
established and maintained.
Zone of aeration - That soil zone in which some of the pores are filled
with air. Unsaturated.
Zone of saturation - That soil zone in which all of the pores are filled
with water. Saturated.
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SECTION IX
APPENDICES
Page No.
A. Chemical Soil Stabilizers, Mulches, and
Mulch Tacks 78
B. Erosion and Sediment Control Structures 97
C. Fiber Mulches, Mulch Blankets, and Nettings .... 163
D. Special Erosion and Sediment Control Practices . . . 193
Product and/or practice listings in the Appendices do not constitute
endorsement by the Environmental Protection Agency. All of the products
listed in these Appendices are available on the commercial market and
they have been used according to the manufacturers' recommendations.
Requests for specific information regarding use, handling limitations,
toxicity, etc., should be directed to the manufacturer.
It is also understood that this listing may not be all inclusive. Other
similar products and/or practices may be available for use and their
exclusion is in no manner a reflection on their utility or quality.
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APPENDIX A
CHEMICAL SOIL STABILIZERS, MULCHES,
AND MULCH TACKS
78
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FIGURE A-l. Chemical soil stabilizer being applied to an area
that will be seeded at a later date
FIGURE A-2. Chemical mulch tack being applied to straw mulch
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.
t
'!
' ****** "' ' *
.•Jf .r* ""-'
.. •'• •
FIGURE A-3.
Chemical mulch being applied in a hydroseeder
slurry with lime, fertilizer, and seed
NOTES:
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AEROSPRAY® 52 BINDER
Technical Information
DESCRIPTION:
AEROSPRAY® 52 BINDER is a milk-white colored, viscous, water
dispersible alkyd emulsion. It is nontoxic and nonphytotoxic and
the pH is 8-9.
OBJECTIVE:
Temporary Soil Stabilization - On denuded areas it penetrates
the soil and binds soil particles into a coherent mass that
reduces erosion by water.
Chemical Mulch - On seeded areas it penetrates the soil and binds
soil particles into a coherent mass. Water and air movement
into the soil is maintained.
WHERE USED:
AEROSPRAY® 52 BINDER is used as a temporary soil stabilizer
and mulch on all types of soil surfaces.
GENERAL APPLICATION REQUIREMENTS:
Various dilution ratios and application rates have been developed
by the manufacturer and this chemical should be applied in accor-
dance with the manufacturer's recommendations if optimum
results are to be achieved. Some general guidelines are listed
below. On steeply inclined, exposed slopes AEROSPRAYR 52
BINDER should be applied in concentrated form at the rate of one
gallon per 100 square feet. When used on a seedbed, it is applied
at a rate of 30-45 gallons of concentrate per acre in dilution ratios
that vary up to 10 parts of water to one of chemical.
MEANS OF APPLICATION:
In general, it can be applied with any nonair entraining equipment
employed for applying liquid fertilizer, asphalt emulsions, and
water. It can also be applied on small plots with garden type hand
sprayers. Hydroseeder agitation devices should be disengaged
after initial mixing of the chemical and water to minimize foaming.
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CURING TIME:
AEROSPRAV® 52 BINDER dries in four hours at 90°F, and in
eight hours at 60°F and 50 percent relative humidity.
HANDLING LIMITATIONS:
Will freeze, but freezing will not damage the product.
MANUFACTURER:
American Cyanamid Company
Industrial Chemicals and Plastics Division
Wayne, New Jersey 07970
NOTES
82
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AQUATAIN
Technical Information
DESCRIPTION:
AQUATAIN is a water dispersible liquid concentrate containing
sodium polypectate, glycerin, and ammonia. It is nontoxic and
nonflammable.
OBJECTIVE:
Chemical Mulch - Partially binds surface soil in order to reduce
erosion and evaporation losses and thereby favorably affect
the development of a permanent vegetative cover. May be
used in hydroseeder slurries as well as on preseeded areas.
WHERE USED:
AQUATAIN is used as a chemical mulch on all types of soil
surfaces.
GENERAL APPLICATION REQUIREMENTS:
AQUATAIN is generally mixed with water at a ratio of one part
AQUATAIN to 5. 5 parts water. An application rate of approxi-
mately 3 gallons AQUATAIN, plus the required water, per 1000
square feet of surface area is normally required for most soil
surfaces.
MEANS OF APPLICATION:
AQUATAIN can be applied with a hydroseeder along with seed and
fertilizer. Equipment used for applying asphalt emulsions and
water can also be used to apply AQUATAIN with little or no modifi-
cation. For small areas, the chemical is generally applied with
small hand operated sprayers.
CURING TIME:
No information available.
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HANDLING LIMITATIONS:
None listed, but the chemicals are carried in water so the product
must be stored in above freezing temperatures.
MANUFACTURER:
The Larutan Corporation
1424 South Allec Avenue
Anaheim, California 92805
NOTES
84
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'CURASOL AE
Technical Information
DESCRIPTION:
(R)
CURASOL AE is a milky-white, polyvinyl acetate copolymer
emulsion. It is physiologically harmless and has no phytotoxic
properties. The pH value is 4-5 and it is water dispersible.
OBJECTIVE:
Temporary Soil Stabilization - Temporarily binds surface soil
in denuded areas in order to reduce water erosion.
Chemical Mulch - Partially binds surface soil in order to reduce
erosion and evaporation losses and thereby favorably affect
the development of a permanent vegetative cover. May be
used in hydroseeder slurries as well as on preseeded areas.
Mulch Tack - Binds natural fiber mulches to reduce losses caused
by wind and rain.
WHERE USED:
^CURASOL AE is used as a temporary soil stabilizer, mulch, and
mulch tack on all types of soil surfaces.
GENERAL APPLICATION REQUIREMENTS:
For use as a chemical mulch and/or soil stabilizer, the amounts
of CURASOL AE and water generally required per acre of area
are as follows:
Flat Areas - 30 gallons ®CURASOL AE to 1000 gallons of water
for moist soil. For dry soil use 2000 gallons of water.
3:1 to 2:1 Slopes - 40 to 55 gallons ®CURASOL AE to 1000 gallons
of waterTor moist soil. For dry soil use 2000 gallons of
water.
1-1/2:1 Slopes - 55 to 65 gallons ®CURASOL AE to 1000 gallons
of water for moist soil. For dry soil use 2000 gallons of
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Swales and Ditches - 90 to 100 gallons ^CURASOL AE to 1000
gallons of water for moist soil. For dry soil use 2000
gallons of water.
MEANS OF APPLICATION:
" CURASOL AE can be applied with a hydroseeder along with the
seed and fertilizer. Spraying equipment normally used for applying
asphalt emulsions or water can also be used, with little or no
modification, to apply the binder.
CURING TIME:
Curing time is dependent upon weather conditions, but is generally
2-6 hours after application.
HANDLING LIMITATIONS:
Will freeze at 23°F. Can be applied at temperatures above 34°F.
Treated surfaces should be traffic free except when very high
concentrations of material are used. May be sprayed on wet or
dry soil. May be stored at least 6 months, but should not be
stored in extreme heat, sunlight, or subfreezing conditions.
MANUFACTURER:
American Hoechst Corporation
1041 Route 202-206 North
Bridgewater, New Jersey 08876
NOTES
86
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®CURASOL AH
Technical Information
DESCRIPTION:
CURASOL AH is a milky-white, high-polymer synthetic resin
dispersion. It is physiologically harmless and has no phytotoxic
properties. The pH value is 4-5 and it is water dispersible.
OBJECTIVES:
Temporary Soil Stabilizer - Temporarily binds surface soil in
denuded areas in order to reduce water erosion. Chemical
specially designed for use under freeze-thaw conditions or
when stabilized area is subject to some traffic.
Mulch Tack - Binds natural fiber mulches to reduce losses caused
by wind and rain.
WHERE USED:
CURASOL AH is used as a temporary soil stabilizer and mulch
tack on all types of soil surfaces.
GENERAL APPLICATION REQUIREMENTS:
Straw Mulch Tack - Under normal conditions, using a mulch
blower, a mixture of 30 to 45 gallons of ^CURASOL AH
and 150 to 300 gallons of water is generally required to
tack one acre of mulch. A greater quantity of water,
generally 300 to 500 gallons, is required when the tack
is applied with a hydroseeder.
Hay Mulch Tack - a mixture of 20 to 30 gallons of ®CURASOL AH
and 150 to 300 gallons of water is generally required for one
acre of area when the tack is applied with a mulch blower.
Using a hydroseeder, a greater quantity of water, generally
300 to 500 gallons, is required in the mixture.
MEANS OF APPLICATION:
®CURASOL AH can be applied with a mulch blower or hydroseeder
and with sprayers normally used for applying asphalt emulsions
or water.
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CURING TIME:
Curing time is dependent upon weather conditions, but is generally
1-6 hours after application.
HANDLING LIMITATIONS:
Will freeze at 23°F. Can be applied at temperatures above 41°F.
May be stored under normal conditions for at least six months.
Should not be exposed to strong sunlight or heat. Must be pro-
tected from frost.
MANUFACTURER:
American Hoechst Corporation
1041 Route 202-206 North
Bridgewater, New Jersey 08876
NOTES
88
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DCA-70
Technical Information
DESCRIPTION:
DCA-70 is a milky-white, viscous, water dispersible polyvinyl
acetate emulsion. It is nonflammable, nontoxic, and nonphytotoxic.
The pH ranges from 4 to 6.
OBJECTIVE:
Temporary Soil Stabilizer - On denuded areas it penetrates the
soil and binds soil particles into a coherent mass that
reduces erosion by water.
Chemical Mulch - Partially binds surface soil in order to reduce
erosion and evaporation losses and thereby favorably affect
the development of a permanent vegetative cover. May be
used in hydroseeder slurries as well as on preseeded areas.
Mulch Tack - Binds natural fiber mulches to reduce losses caused
by wind and rain.
WHERE USED:
DCA-70 is used as a temporary soil stabilizer, mulch, and mulch
tack on all types of soil surfaces.
GENERAL APPLICATION REQUIREMENTS:
Various dilution and application rates will depend on soil, slope,
etc., conditions and the material should be applied in accordance
with manufacturer's recommendations. However, general require-
ments are as follows:
Soil Stabilizer - Mix one part DCA-70 to one part clean water and
apply 0. 5 or more gallons per square yard.
Chemical Mulch - Mix one part DCA-70 to 20 or more parts of
clean water and apply 0. 5 gallon per square yard on
permeable soils.
Mulch Tack - Mix one part DCA-70 to 10-20 parts water. Apply
this solution at a rate sufficient to disperse 30-45 gallons
of DCA-70 concentrate per acre.
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MEANS OF APPLICATION:
Equipment used for applying asphalt emulsions and water can be
used to apply DCA-70. Hydroseeders can also be used to apply
the chemical with little or no modification.
DCA-70 cures in one hour at 90°F and two hours at 60°F and
CURING TIME:
DCA-70 c
50 percent relative humidity.
HANDLING LIMITATIONS:
Solids separation occurs in temperatures below 40 F.
MANUFACTURER:
Union Carbide Corporation
Chemicals and Plastics
270 Park Avenue
New York, New York 10017
NOTES
90
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LIQUID ASPHALT
Technical Information
DESCRIPTION:
The basic component is asphalt cement. It is dispersed or sus-
pended in water or various solvents.
OBJECTIVE:
Mulch Tack - Binds natural fiber mulches to reduce losses caused
by wind and rain.
Chemical Mulch - Partially binds surface soil in order to reduce
erosion and evaporation losses and thereby favorably
affect the development of a permanent vegetative cover,
WHERE USED:
Liquid Asphalt is used as a mulch tack and chemical mulch on all
types of soil surfaces.
GENERAL APPLICATION REQUIREMENTS:
Chemical Mulch - Apply Liquid Asphalt or emulsified asphalt as a
spray at the rate of 0. 15-0. 30 gallon per square yard, de-
pending upon soil and slope conditions.
Mulch Tack - ApplyLiquid Asphalt at a rate of 0.1 gallon per square
yard and emulsified asphalt at a rate of 0. 04 gallon per
square yard.
MEANS OF APPLICATION:
Asphalt may be applied by hand-spray nozzle or with an offset
distributor bar attached to an asphalt distributor truck.
CURING TIME:
Varies widely for various types of asphalt and weather conditions,
but is generally 24 hours.
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HANDLING LIMITATIONS:
Will adhere to shoes, etc., unless completely cured. Special
care must be used when applying so that material will not drift
beyond the area being mulched.
PRODUCT INFORMATION SERVICE:
The Asphalt Institute
Asphalt Institute Building
College Park, Maryland 20740
NOTES
92
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PETROSET® SB
Technical Information
DESCRIPTION:
PETROSET® SB is a light tan colored oil in water emulsion of high
strength rubber. It is free flowing and is water dispersible. The
material is not flammable and is not toxic to humans or animals.
OBJECTIVE:
Temporary Soil Stabilization - On denuded areas it penetrates the
soil and binds soil particles into a coherent mass that reduces
erosion by water.
Chemical Mulch - On seeded areas it penetrates the soil and binds
soil particles into a coherent mass. Water and air movement
into the soil is maintained.
Mulch Tack - Binds natural and synthetic fiber mulches together and
thereby reduces loss of mulch due to removal by wind and rain.
WHERE USED:
Used as a temporary soil stabilizer, mulch, and mulch tack on all
types of soil surfaces.
GENERAL APPLICATION REQUIREMENTS:
Numerous dilution ratios (i. e., parts of PETROSET®SB to parts
of water) and application rates (also, spreading rates) have been
developed by the manufacturer for different soil textures, desired
penetrations, and intended usages. In general, the greater the
dilution ratio (i. e., the greater the percentage of water) the deeper
the penetration of the binder and the weaker the binding strength for
a given soil condition. In addition, the finer the soil texture the
greater the dilution ratio and application rate required to achieve a
desired penetration. For example, in order to protect against
normal rainwater and wind erosion and obtain a penetration of
approximately 1/2 inch, a fine textured (fine grained) soil generally
requires an application rate of one gallon dilute PETROSET®SB,
having a dilution ratio of 1:14, per square yard. In order to achieve
the same objective, a coarse textured soil generally requires an
application rate of 0. 4 gallon of dilute PETROSET%B, having a
dilution ratio of 1:5, per square yard. Specific application and
93
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cost formulas and nomographs are furnished by the manufacturer.
MEANS OF APPLICATION:
Practically any spraying equipment capable of delivering the
desired quantity of dilute PETROSET®SB can be used. Distributor
trucks with calibrated spreader bars, as well as hydroseeding
equipment, are suitable for applying the chemical.
CURING TIME:
Thirty minutes after application this product has cured enough to
perform satisfactorily and will not adhere to shoes.
HANDLING LIMITATIONS:
Will freeze, but freezing will not damage the product. Clean
equipment should be used for application. Product contains some
solvents and should therefore be kept away from children. Storage
should be at temperatures of less than 150°F.
MANUFACTURER:
Phillips Petroleum Company
Chemical Department
Commerical Development Division
Bartlesville, Oklahoma 74003
NOTES
94
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TERRA TACK
Technical Information
DESCRIPTION:
TERRA TACK is a highly concentrated, water dispersible chemical,
marketed in powdered form which forms a thick green liquid when
mixed with water.
OBJECTIVE:
Chemical Mulch - Partially binds surface soil in order to reduce
erosion and evaporation losses and thereby favorably affect
the development of a permanent vegetative cover. May be
used in hydroseeder slurries as well as on preseeded areas.
Mulch Tack - Binds natural fiber mulches to reduce losses caused
by wind and rain.
WHERE USED:
TERRA TACK is used as a chemical mulch and mulch tack on dry
or porous soil surfaces.
GENERAL APPLICATION REQUIREMENTS:
For wet application in combination with seeding, an application rate
of 50 pounds of TERRA TACK in 2000 gallons of water is recommended
per acre. For dry application in combination with seeding, use 86
pounds per acre. When used as a mulch tack for long fiber mulches
such as straw or hay, a mixture ratio of 1:20 parts water is recom-
mended. This slurry should be applied at a rate of 1000 gallons
per acre. For use with short fiber mulches like wood fiber mulch,
a ratio of 1:40 is applied at a rate of 2000 gallons of slurry per acre.
MEANS OF APPLICATION:
Standard hydroseeding equipment used for applying seed, fertilizer,
and certain mulches can be employed with little or no modification.
For dry application, standard hopper spreaders used for applying
fertilizers or lime can be utilized.
95
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CURING TIME:
No specific curing information is available, but the manufacturer
recommends application on dry soil at least two hours before sunset
or rainfall.
HANDLING LIMITATIONS:
Avoid contact with skin and eyes. Avoid breathing dust or solution
spray. Wash body thoroughly after using TERRA TACK. Tank life
is limited to several hours, so use immediately after mixing.
MANUFACTURER:
Grass Growers, Inc.
P.O. Box 584
Plainfield, New Jersey 07061
NOTES
96
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APPENDIX B
EROSION AND SEDIMENT
CONTROL STRUCTURES
97
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CHECK DAMS
DEFINITION:
A Check Dam is a structure used to stabilize the grade or to con-
trol head cutting in natural or artificial channels.
OBJECTIVE:
Check Dams are used to reduce or prevent excessive erosion by
reduction of velocities in watercourses or by providing partial
lined channel sections or structures that can withstand high flow
velocities.
WHERE USED:
Check Dams are used where the capability of earth and/or
vegetative measures is exceeded in the safe handling of water at
permissible velocities, where excessive grade or overfall con-
ditions occur, or where water is to be lowered from one elevation
to another.
CONSTRUCTION RECOMMENDATIONS:
Formal design is generally required.
a. Overfall structures of concrete, metal, rock, gabions,
Fabriform®, wood, etc., may be used in the construction
of check dams.
b. The structure should be located in a reasonably straight
channel section and particular attention must be given to
the effect that new water levels will have on existing
natural and man-made features.
c. Site and foundation conditions and aesthetic considerations
are important factors in construction material selection.
d. Design channel grade above and below the structure should
be analyzed to determine if erosion or sediment deposition
will be a problem.
MAINTENANCE:
Generally not required.
98
-------
FIGURE B-l. Check Dams constructed of gabions and rock riprap
'
FIGURE B-2. Rock and wood check dam
99
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NOTES
100
-------
CHUTES/FLUMES
Technical Information
DEFINITION:
Chutes/Flumes are channels of concrete or comparable material
that is designed to conduct runoff downslope.
OBJECTIVE:
Chutes/Flumes conduct storm runoff from one elevation to another
without erosion of the slope.
WHERE USED:
Chutes/Flumes are used as temporary, interim, or permanent
structures down slopes where concentrated runoff would cause
slope erosion.
CONSTRUCTION RECOMMENDATIONS:
Formal design guidance is usually required to properly size the
proposed structure.
Placement - On undisturbed soil or well compacted fill.
Slope - No steeper than 1. 5:1 (horizontal to vertical) nor flatter
than 20:1.
Elevation - Top of the lining of the inlet structure must not be
Fngher in elevation than the lowest top elevation of
training beams or other devices that direct overland
flow to the chute or flume.
Outlet Protection - Some form of energy dissipating device
should be incorporated into the outlet structure at the
toe of the slope.
Entrance Structure - Shall slope toward the outlet at 0. 25 to
1. 2 inches per foot.
Compaction - Insure that a good bond is attained at the inter-
face of the structure and training berms.
Outlet - To stabilized area.
101
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MAINTENANCE:
Inspect for damage after each storm if the structure is of a
temporary or interim nature. Inspect for signs of piping failure
at interface of entrance structure and training berms.
Sect. AA
FIGURE B-3. Chute/flume
102
-------
FIGURE B-4. Flume with energy dissipators
FIGURE B-5. Concrete chute
103
-------
FIGURE B-6. Concrete chute
NOTES:
104
-------
DIVERSION DIKE
Technical Information
DEFINITION:
A Diversion Dike is a temporary ridge of soil constructed at the
top of cut or fill slopes.
OBJECTIVE:
Diversion Dikes divert overland flow from small areas away from
unstabilized slopes.
WHERE USED:
Diversion Dikes are used as a temporary or interim measure at
the top of a newly constructed slope.
CONSTRUCTION RECOMMENDATIONS:
Formal design often not required.
General criteria include:
Height: 1. 5 feet
Top Width: 2 feet
Side Slopes 2:1 or flatter
Compaction: Should be 85 percent standard
density
Grade: Dependent upon topography - must
be positive. Excessive grades may
require additional stabilization in
flow area.
Other: In wooded areas where top of slope
access is limited, diversion dikes
can be constructed as a dozer finishes
the slope by carrying soil upslope
and dumping it at crest. Compaction
is sacrificed in this instance.
MAINTENANCE:
Inspect after each rain to locate any damaged areas. Repair must
be completed before next storm to ensure against the outlet of
195
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concentrated flow to the surface of the bare slope. Any channel
obstructions should be removed.
Cut or
Fill
2:1 Slope or Flatter
CROSS SECTIONS
Outlet Onto
Stabilized Area
Upslope Toe
Positive Grade,
General Notes:
Cut or Fill Slope
PLAN VIEW
a. Drawings not to scale.
b. Outlet to stabilized area.
FIGURE B-7. Diversion dike
106
-------
FIGURE B-8. Diversion dike at top of slope
FIGURE B-9. Diversion dike constructed by dozer moving soil
upslope and dumping at top of slope
107
-------
FIGURE B-10. Diversion on a stabilized slope
NOTES:
108
-------
EROSION CHECK
Technical Information
DEFINITION:
Erosion Checks comprise a technique whereby porous, mat-like
material is installed in a slit trench that is oriented perpendicular
to the direction of flow in a ditch or swale. It prevents the for-
mation of rills and gullies by permitting subsurface water migra-
tion without the removal of soil particles.
OBJECTIVE:
The nonerodible erosion check prevents the formation of rills
and gullies by permitting subsurface water migration without the
removal of soil particles and by providing positive grade control
of surface flow.
WHERE USED:
Erosion Checks are used at predetermined intervals across the
center line of ditches and swales in which vegetative cover is being
established. They can be used on critical slopes where severe
sheetflow problems may occur.
CONSTRUCTION RECOMMENDATIONS:
See Figure B-ll.
Material - Flexible, porous, long lived mats or membranes of
fiber glass, plastic, etc.
Location in ditch or swale
(1) Immediately downstream from every tributary
discharge point.
(2) At each point of change in gradient (steep to shallow
and shallow to steep).
(3) Remaining channel: 20-75 foot centers depending
upon slope, soil type and condition, etc. Solicit
guidance from local conservationists experienced
with this technique.
109
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Depth - The bottom of the erosion check shall be installed at least
three inches below the maximum depth at any existing rill
or gully and 8-12 inches deep in newly graded areas.
Lateral Extent - Must be carried to an elevation at least 6 inches
above the design flow elevation to protect against rill
formation during intense runoff events.
Anchoring - Staple material to bottom of trench and to vertical
side of slit trench on 24 inch centers.
Backfilling - Slit trench must be backfilled and carefully com-
pacted after erosion check has been installed. Trim flush
with soil surface. Reseed area disturbed by erosion check
construction.
Cap strip - Any conventional mat or blanket material used in the
establishment of vegetation in swales or ditches can be
used (Appendix C). The cap strip should extend about
2 feet to each side (upstream and downstream) of the
erosion check and is applied in addition to any other
mulching material used for vegetative establishment. It
should be stagger stapled on 6-9 inch centers along the
erosion check. Conventional staple configuration can be
used on the remainder of the cap strip.
Timing - Install immediately after final grading and/or seed-
Bed preparation.
MAINTENANCE:
Inspect for erosion damage and replace or repair as necessary.
Maintain a strong, healthy vegetative stand by regular fertilization.
GENERAL NOTES:
A combination of short, warm season grasses and nondegradable
nettings of plastic and fiber glass have been used successfully as
a modification of the cap strip. The dense root mat of the warm
season grass and the strength provided by the netting in addition
to the erosion check have given superior performance in the con-
trol of rill and gully formation in swales and ditches. The spread-
ing of the warm season grass can be controlled by using taller
grasses to surround the cap strip area. The shade provided by
a 6-inch stand of grass will discourage the spreading of the warm
season grass.
110
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SECT.-A A
NO sc*-i_e
1. Cutaway of fiber glass installation in bottom of trench.
2. Cutaway of fiber glass installation in trench with spoil pile.
3. Trench with fiber glass erosion check installed.
4. Cap strip of blanketing material over completed erosion check.
FIGURE B-ll. Erosion check
-------
FIGURE B-12. Fiber glass erosion check in trench - awaiting backfill
, ~
FIGURE B-13. Fiber glass erosion check and well-established vegetation
112
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NOTES
H3
-------
FABRIFORWf EROSION CONTROL MATS
DEFINITION:
The Fabriforrr^ process is a technique for pressure injecting
fluid mortar into flexible fabric forms.
OBJECTIVE:
Fabriform^ mats provide structure, slope, and grade protection,
both above and below the waterline.
WHERE USED:
FabrifornV^1 mats are used in shoreline stabilization, levee facing,
channel lining, and the construction of revetments and check dams.
Material type - Filter point mats are designed to relieve hydro-
static uplift pressures. They also tend to articulate along
the lines of the filter points to minimize undercutting.
Flow-alteration characteristics of the cobble like surface
of Filter Point mats make them effective in slowing water
velocity in fast streams and at outfall installations.
Uniform Cross Section mats are recommended for installa-
tion where the primary objective is impermeability and low
hydraulic friction.
CONSTRUCTION RECOMMENDATIONS:
Formal design required.
Utmost care must be exercised to ensure that toe trenches are
designed and constructed at elevations and in such manner that
will not allow undercutting. The following information is pre-
sented to show, by example, the procedure followed in the in-
stallation of a typical revetment. It is for information purposes
only and design and construction guidance on specific projects
should be secured from professionals familiar with the use of
Fabriform® mats.
a. Remove stumps, boulders, and brush from the site.
Grade sufficiently to provide a slope which is stable in
the absence of erosive forces. In general, an average
slope steeper than 1:1 is not recommended. Cut an upper
toe trench to prevent undercutting of the mat in event of
heavy runoff.
114
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b. Beginning upstream, prefabricated fabric panels, usually
from 2000 to 3000 square feet each in area, are placed
over the embankment with seams straight and preferably
perpendicular to the shoreline. The flexible, lightweight
nylon fabric is usually placed by hand. Guide ropes to the
opposite shore or small boats may also be used to assist
in fabric placement.
c. Fabric panels as delivered to the job are field-sewn
together with heavy nylon thread to create a monolithic
structure of any required length and width. Seams are
sewn in the field with a portable air-operated or electric
bag closer.
d. Ready mix mortar is injected into the fabric envelope with
a mortar pump, usually having a capacity of from 10 to 12
cubic yards per hour. The fabric in the toe trench is
pumped first to serve as an anchoring and positioning
function. Next, the undercut portion of the mat is pumped
followed by filling the remaining section of the fabric.
Production rates as high as 1000 square feet per man per
day have been achieved on large projects.
e. The toe trench at the top of the mat is then backfilled.
MAINTENANCE:
Periodic inspection for signs of undercutting or excessive erosion
at transition areas.
MANUACTURER:
Construction Techniques, Inc.
1111 Superior Building
Cleveland, Ohio 44114
H5
-------
(ffi
FIGURE B-14. Fabriform® mat in place - awaiting filling
FIGURE B-15. Completed Fabriform® (filterpoint) structure
116
-------
(R)
FIGURE B-16. Fabriform J channel lining being filled
®
FIGURE B-17. Fabriform^ channel lining being filled
Note uninterrupted stream flow .
117
-------
FIGURE B-18. Fabriform® (uniform cross section) check dam
NOTES:
118
-------
FILTER BERM
Technical Information
DEFINITION:
A Filter Berm is a temporary ridge of gravel or crushed rock
constructed across a graded right-of-way.
OBJECTIVE:
Filter Berms retain sediment on-site by retarding and filtering
runoff while at the same time allowing construction traffic to
proceed along the right-of-way.
WHERE USED:
Filter Berms are used primarily across graded rights-of-way
that are subject to vehicular traffic. Also applicable for use in
drainage ditches prior to roadway paving and establishment of
permanent ground cover.
CONSTRUCTION RECOMMENDATIONS:
Formal design not required. Minimum requirements for use on
graded rights-of-way are generally as follows:
Height: 1. 5-2 feet (uniform top elevation)
Top Width: 3-5 feet
Side Slopes: 3:1 or flatter
Spacing: 200-300 feet (steeper slopes require
closer spacing)
Material: Coarse (3/4"-3"), well graded gravel
or crushed rock. Fines less than
5 percent.
MAINTENANCE:
Removal of trapped sediment and cleanout or replacement of
clogged filter material after each storm.
119
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Flow
Direction
Paved
Street
Graded
R.O.W.
PLAN
Graded R. o. W. ;
SECTION
GENERAL NOTES:
a. Drawings not to scale.
b. Top width may be widened; slopes may be flattened.
c. Outlet should function with minimal erosion. Outlet
availability should be considered in structure location.
A temporary grade stabilization structure is required
where outlet is to a critical area.
FIGURE B-19. Filter berm
120
-------
BB^^B!B^^W(HP'•—••- , --.li.-.'.' --v.
•* -
FIGURE B-20. Filter berm - installed
*'•" ****' ' C
mm*
. •' •
FIGURE B-21. Filter berm - installed
121
-------
NOTES
122
-------
FILTER INLET
Technical Information
DEFINITION:
A Filter Inlet is a temporary filter of gravel or crushed rock
constructed at storm sewer curb inlet structures.
OBJECTIVE:
Filter Inlets retain sediment on-site by slightly retarding and
filtering storm runoff before it enters the storm sewer system.
WHERE USED:
Filter Inlets are used at storm sewer curb inlets.
CONSTRUCTION RECOMMENDATIONS:
Formal design not required.
a. Several different design concepts are in use. One utilizes
concrete building blocks in the throat of the inlet. The
filter material is then placed between the blocks and the
street in the gutter section.
b. A second concept does not use concrete blocks. A ridge
of filter material is built around the inlet throat. It is
kept out of the storm sewer by boards across the throat;
the filter material is about half as deep as the inlet open-
ing. Large volumes of water flow over the top of this
filter inlet.
c. All filter material should be coarse (3/4"-3"), well graded
gravel or crushed rock. Fines should be less than 5 percent.
MAINTENANCE:
Remove trapped sediment and clean out or replace clogged filter
material after each storm.
123
-------
B
B-J
Plan
/^^
Section A-A
Section B-B
Not to scale.
FIGURE B-22. Filter inlet
•
FIGURE B-23. Filter inlet - installed
124
-------
11
m
,.
FIGURE B-24. Filter inlets - installed
'" '..*• j:,*^ '
t» ,•• 'V , >i ?
, isii' ,'• / ; § ,. \ ,^* ,* _- ;*:
FIGURE B-25. Filter inlet requiring maintenance
125
-------
Isometric
Section
FIGURE B-26. Filter inlet
FIGURE B-27. Filter inlet - installed
126
-------
NOTES
127
-------
FLEXIBLE DOWNDRAIN
Technical Information
DEFINITION:
A Flexible Downdrain is a flexible conduit of heavy duty fabric
or other material.
OBJECTIVE:
Flexible Downdrains conduct storm runoff from one elevation to
another without erosion of the slope.
WHERE USED:
Flexible Downdrains are used as a temporary or interim structure
down slopes where concentrated runoff would cause excessive
slope erosion.
CONSTRUCTION RECOMMENDATIONS:
Formal design not required.
Placement - On undisturbed soil or well compacted fill.
Diameter - Sufficient to convey maximum runoff expected during
the life of the drain.
End Sections - Standard metal. Entrance section should slope
toward outlet at rate of at least 1/2" per foot. Soil should
be carefully placed and compacted around entrance section
to ensure against piping failure along end section and
extension collar.
Extension Collars - 12" long, corrugated metal pipe.
DO NOT USE HELICAL PIPE.
Securing Straps - Fabric, metal, etc., secured in at least one
corrugation of extension collar.
Anchors - Metal "T" pins anchored in soil through grommets
attached to the flexible downdrain. 20 foot centers.
Outlet - To stabilized area wherever possible.
128
-------
MAINTENANCE:
Inspect for clogging or damage after each storm. In below freezing
weather, check to ensure that sides of collapsed downdrain are not
frozen together. Do not allow placement of any material on col-
lapsed downdrain. Inlet section should be checked for indications
of piping along metal sections. Anchors should be resecured as
necessary.
MANUFACTURER:
Reliance Plastic and Chemical Corporation
110 Kearney Street
P. O. Box 2627
Paterson, New Jersey 02509
Top of Diversion
Dike
Holding flaps
Standard metal
end section
PLAN VIEW
full
^^J
Anchor pins r
Extension
collar
Strap
FIGURE B-28. Flexible downdrain
129
-------
FIGURE B-29. Flexible downdrain - isometric
FIGURE B-30. Flexible downdrain - installed
130
-------
•-.;-.,..^ . , • . .;-v^:JwJt-'
FIGURE B-31. Flexible downdrain inlet structure
NOTES:
131
-------
GABIONS
Technical Information
DEFINTION:
Gabions are large, multi-celled, rectangular wire mesh boxes.
OBJECTIVE:
Rock filled baskets, properly wired together, form flexible
monolithic building blocks used for construction of erosion
control structures.
WHERE USED:
Gabions are used in channels, revetments, retaining walls,
abutments, check dams, etc.
CONSTRUCTION RECOMMENDATIONS:
Formal design required. Construction plans and drawings should
be prepared by professionals familiar with the use of gabions.
Erosion and sediment control construction design should ensure
that foundations are properly prepared to receive gabions, that
the gabion structure is securely "keyed" into the foundation and
abutment surfaces, and that rock used is durable and adequately
sized to be retained in the baskets.
MAINTENANCE:
Periodic inspection for signs of undercutting or excessive erosion
at transition areas.
MANUFACTURER OR SUPPLIER:
Bekaert Steel Wire Corporation
Terra Aqua Conservation Division
4930 Energy Way
Reno, Nevada 89502
Maccaferri Gabions of America, Inc.
55 West 42nd Street
New York, New York 10026
132
-------
FIGURE B-32. Gabions - channel bank protection
FIGURE B-33. Gabions - channel bank protection
133
-------
FIGURE B-34. Gabions - protection at stream bend
FIGURE B-35. Gabions - channel lining, check dam, and
bank protection
134
-------
NOTES
135
-------
INTERCEPTOR DIKE
Technical Information
DEFINITION:
An Interceptor Dike is a temporary ridge of compacted soil
constructed across a graded right-of-way.
OBJECTIVE:
Interceptor Dikes reduce erosion by intercepting storm runoff
and diverting it to temporary outlets where it can be disposed of
with minimal erosion.
WHERE USED:
Interceptor Dikes are used across graded rights-of-way that
are not subject to vehicular traffic.
CONSTRUCTION RECOMMENDATIONS:
Formal design often not required. Minimum requirements for
use on graded rights-of-way are generally as follows:
Height: 1.5 feet
Top Width: 2 feet
Side Slopes: 2:1 or flatter
Spacing: 200-300 feet (Steeper slopes require
closer spacing.)
Material: Compacted soil
MAINTENANCE:
Inspect after each rain to locate any damaged areas. Repairs
must be completed before next storm to ensure against structural
failure.
136
-------
2:1 or Flatter Slopes
CROSS SECTION
:1 or Flatter
Slopes
Upslope Toe
A--Outlefonto Stabilized Area
PLAN VIEW
GENERAL NOTES:
a. Drawings not to scale.
h. Top width may be widened, slopes may be flattened.
c. Outlet should function with minimal erosion.
FIGURE B-36. Interceptor dike
137
-------
T-
•„,_"
FIGURE B-37. Interceptor dike - installed and outletting
to storm sewer inlets
FIGURE B-38. Interceptor dike - installed
138
-------
NOTES
139
-------
LEVEL SPREADER
Technical Information
DEFINITION:
A Level Spreader is an outlet constructed at zero grade across a
slope where concentrated runoff may be spread at nonerosive
velocities over undisturbed areas stabilized by existing vegetation.
OBJECTIVE:
Level Spreaders convert concentrated flow into sheet flow for outlet
at nonerosive velocities onto areas stabilized by vegetation.
WHERE USED:
Level Spreaders are used at locations where concentrated runoff
from unstabilized areas can be diverted onto stabilized areas
under sheet flow conditions.
CONSTRUCTION RECOMMENDATIONS:
Formal design is often not required, but extreme care must be
used during construction to ensure that outlet lip is exactly level
and uniform from end to end. Failure to meet these requirements
will cause concentrated flow and consequent erosion of the stabilized
area.
Depth below level lip: at least 0. 5 ft
Length:
Flow (cfs) Minimum Length (in feet)
up to 10 15
10-20 20
21-30 26
31-40 36
41-50 44
Width: at least 6 feet from center line to level
lip
140
-------
Back Slope:
Material:
2:1 or Hatter
Must be constructed in undisturbed
soil and must outlet onto an area
stabilized with vegetation.
MAINTENANCE:
Inspect for damage after each storm. Repair as required.
Undisturbed Soil
Stabilized by
Existing Vegetation
Drawing not to scale.
FIGURE B-39. Level spreader
NOTES
141
-------
SANDBAG SEDIMENT BARRIERS
Technical Information
DEFINITION:
Sandbag Sediment Barriers are temporary barriers or diversions
that are constructed of sandbags.
OBJECTIVE:
The barriers are built to retain sediment on-site by slowing storm
runoff and causing the deposition of sediment at the structure.
WHERE USED:
Sandbag Sediment Barriers are used at storm drain inlets, across
minor swales and ditches, and for other applications where the
structure is of a temporary nature.
CONSTRUCTION RECOMMENDATIONS:
a. Should be installed so that flow under or between bags
is minimal.
b. Anchoring with steel rods may be required if structure
height exceeds two bags.
MAINTENANCE:
Target for vandals; daily inspection required. Clean out trapped
sediment after each storm.
143
-------
-•*,
'
FIGURE B-40. Sandbags at site for construction of sediment
control structure
FIGURE B-41. Sandbag structure in place
143
-------
NOTES
144
-------
SECTIONAL DOWNDRAIN
Technical Information
DEFINITION:
A Sectional Downdrain is a prefabricated, sectional conduit of
half-round or third-round, bituminized fiber pipe or other material.
OBJECTIVE:
Sectional Downdrains conduct storm runoff from one elevation to
another without erosion of slope.
WHERE USED:
Sectional Downdrains are used as a temporary, interim, or
permanent structure on slopes where concentrated runoff would
cause excessive slope erosion.
CONSTRUCTION RECOMMENDATIONS:
Formal design required to size pipe.
Placement - On undisturbed soil or compacted fill.
Diameter - Sufficient to carry design flow without spilling
from pipe.
Installation Procedure - Supplied by manufacturers in
pamphlet form. Skilled labor not required.
Outlet - To stabilized areas only.
MAINTENANCE:
Inspect for damage periodically.
MANUFACTURER:
Sonoco Product Company
Hartsville, South Carolina 29550
145
-------
ro
FIGURE B-42. Sectional downdrain FIGURE B-43. Sectional downdrain used as a ditch liner
-------
V
FIGURE B-44. Sectional downdrain
NOTES:
147
-------
SEDIMENT RETENTION BASINS
Technical Information
DEFINITION:
A Sediment Retention Basin is a temporary dam or basin or a
combination of both that will trap and store sediment produced on
exposed areas and delivered to the structure by storm runoff.
OBJECTIVE:
Sediment Retention Basins trap and retain sediment generated during
construction activities on-site.
WHERE USED:
Sediment Retention Basins are used across channels and drainage-
ways that are on, or adjacent to, construction sites.
DESIGN AND CONSTRUCTION RECOMMENDATIONS:
Formal design is required. The following information has been
prepared by the USDA, Soil Conservation Service for specific use
within the State of Maryland. The text of the USDA specifications
is presented here as an example and is for general interest only.
The appendices to the USDA specifications are not included.
U.S. Soil Conservation Service November 1969
College Park, Maryland
INTERIM STANDARD AND SPECIFICATIONS
FOR SEDIMENT BASIN
DEFINITION, PURPOSE, AND CONDITIONS WHERE APPLICABLE:
A sediment basin is created by the construction of a barrier or
dam across a drainageway, or by excavating a basin, or by a
combination of both, to trap and store sediment from erodible
areas in order to protect properties and stream channels below
the installation from excessive siltation. This specification
applies only to sediment basins that are temporary in nature
and will be removed upon completion of the development period.
148
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Sediment basins that are to remain as a water storage facility
after the development period will be designed and constructed
to conform to Maryland State Law, as found in Article 96A,
Maryland Water Resource Law. This practice applies primarily
to areas where land grading operations are planned or are underway.
It is used as a temporary measure until areas above the installation
are permanently protected against erosion by vegetative or mechan-
ical means.
Sediment basins covered by this standard and specification will
be limited to the following two categories.
Class "X" - Sediment control basins designed with a dam 10 feet
or less in height and with less than one million gallon
storage capacity below the pipe spillway crest.
Class "B" - Sediment basins with the following criteria will fall
in Class "B": The water surface area at the crest elevation
of the pipe spillway shall not exceed nine (9) feet measured
upward from the original stream bed to the crest elevation
of the pipe spillway; and the drainage area shall not exceed
one hundred fifty (150) acres.
NOTE:
This standard and specification shall not apply to sediment basins
in which any of the above criteria for Class "B" sediment basins
is exceeded.
DESIGN:
Storage - The site should be selected to provide adequate storage
for not less than 0. 5 inches per acre of drainage area.
Volume for trap efficiency calculations shall be the volume
below the emergency spillway crest or pipe spillway crest
if there is no emergency spillway. When necessary,
consideration should be given either to excavating additional
storage capacity to meet these requirements or to plan for
periodic cleanout in order to maintain the capacity require-
ments. Where available sites do not lend themselves to
meeting such design criteria, approval should be obtained
from the Soil Conservation District and the responsible county
agency to design and install a sediment basin with less
storage.
149
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NOTE:
Sediment basins shall be cleaned out when the effective storage
capacity drops below 0. 2 inch per acre of drainage area. The
elevation corresponding to this level shall be determined and
given in the design data as a distance below the top of the riser.
0.5 inch of storage per acre of watershed equals 67 cubic yards
per acre of watershed. 0. 2 inch of storage per acre of watershed
equals 27 cubic yards per acre of watershed.
Spillway Design
1. Runoff Computations - Combined capacity of the pipe
and emergency spillways will, where applicable, be
designed to handle a ten-year frequency storm. Runoff
will be figured by an acceptable method and should be
based on soil cover conditions expected to prevail
during the anticipated effective life of the structure.
2. Pipe Spillways - Design the pipe spillway to handle
not less than five inches runoff from the drainage
area for 24 hours (i. e., five inches runoff or 0. 21 cfs
per acre of drainage area). (See Appendix A-2 for
capacity of specific pipe combination.) The pipe spill-
way will consist of a vertical pipe or box type riser
joined to a horizontal pipe (barrel) which will extend
through the embankment. The riser will be perforated
to provide a gradual drawdown in the reservoir to a
planned elevation after each storm event. The hydraulic
efficiency of the pipe spillway may be increased by
using a riser with a cross sectional area of at least
1.5 times the cross sectional area of the horizontal
pipe.
a. Crest Elevation - When used in combination with
emergency spillways, the crest elevation of the
riser shall be at least one foot below the elevation
of the control section of the emergency spillway.
If no emergency spillway is provided, the crest
elevation of the riser shall be at least three feet
below the crest elevation of the embankment.
b. Perforated Riser - The upper portion of the riser
shall be perforated with 1-1/2 inch diameter holes
spaced eight inches vertically and 10-12 inches
horizontally all around. The perforated portion
shall be the top 1/2 to 2/3 of the riser.
150
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c. Antivortex Device - An antivortex device shall
be used on the top of the riser if the discharge
values in the appended charts are used. If no
antivortex device is used, discharge values given
in the charts must be reduced by 50 percent.
An approved antivortex device is a thin, vertical
plate normal to the centerline of the dam and
firmly attached to the top of the riser. The plate
dimensions are: length - diameter of the riser
plus 12 inches; height = diameter of the horizontal
pipe.
d. Base - The riser shall have a base attached
with a watertight connection and shall have
sufficient weight to prevent flotation of the riser.
Two approved bases are: (1) A concrete base
18 inches thick with the riser imbedded six inches
in the base. The base should be square with
each dimension one foot greater than the riser
diameter. (2) A 1/4 inch minimum thickness
steel plate welded all around the base of the
riser to form a watertight connection. The
plate shall be square with each side equal to two
times the riser diameter. The plate shall have
two feet of stone, gravel, or tamped earth
placed on it to prevent flotation.
e. Trash Rack - An approved trash rack shall be
securely attached to the top of the riser.
f. Antiseep Collars - Conduits through embankments
consisting of materials with low silt-clay fractions
shall be provided with antiseep collars where the
pipe diameter is 10 inches or greater. Seep
length should be increased approximately 10
percent. All Class "B" basins shall have a
minimum of one antiseep collar.
3. Emergency Spillway
a. Capacity - The minimum capacity for emergency
(earth) spillway will be that required to pass the
peak flow from design storm less any reduction
creditable to the pipe spillway. Where emergency
spillways are used, the channel bottom shall have
a minimum width of eight inches. Design of
emergency spillways can be determined through
the use of Appendix A-3.
151
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b. Maximum Allowable Velocity - The maximum
allowable velocity in the exit channel shall be
6. 0 feet per second.
c. Vegetative Protection - Provide for the protection
of the embankment and emergency spillway by
vegetative or other suitable means. See Standard
and Specifications for Critical Area Stabilization.
Freeboard - Freeboard is the difference in elevation
between design high water (10 year storm as outlined
above) and the top of the settled embankment. Minimum
freeboard shall be 1. 0 feet for sediment basins with
emergency spillways and 2. 0 feet for those with no
emergency spillway.
Embankment - The embankment shall have a minimum top width of
eight feet. Side slopes shall be no steeper than 2:1 for the
Class "X" sediment basins and no steeper than 2-1/2:1 for
the Class "B" sediment basins. The maximum fill height
shall be 10 feet for Class "X" basins and 15 feet for Class
"B" basins.
Storage Area - Consideration should be given to fencing the sedi-
ment storage area.
CONSTRUCTION SPECIFICATIONS:
Site Preparation - Areas under the embankment and any structural
works shall be cleared, grubbed, and the topsoil stripped to
remove all trees, vegetation, roots, or other objectionable
material. In order to facilitate cleanout and restoration, it
is recommended that the pool area (measured at the top of
the pipe spillway) be cleaned of all brush and trees.
Embankment
1. Material - The fill material shall be taken from
approved designated borrow area or areas. It should
be free of roots, woody vegetation, oversize stones,
rocks, or other objectionable materials. The embank-
ment shall be raised to an elevation which provides for
anticipated settlement to design elevation (allow 10
percent for settlement).
2. Placement - Areas on which fill is to be placed shall be
scarified prior to placement of fill. Fill materials
shall be placed in six inch maximum lifts which are to
be continuous over the entire length of the fill.
152
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3. Compaction - The movement of the hauling and
spreading equipment over the fill should be controlled
so that the entire surface of each lift will be traversed
by not less than one tread track of the equipment or
compaction shall be achieved through use of a roller.
Pipe Spillway Installation - The riser must be rigidly and securely
fastened to the barrel and the bottom of the riser must be
sealed (watertight). The pipe spillway shall discharge at
ground elevation below the dam. All pipe joints must be
securely fastened and watertight.
Emergency (earth) Spillway Installation - Emergency spillways
must be installed and on undisturbed soil (not on fill) by
grading. Entrance and exit channels grade must equal
design grades; length of level control section will be 10 feet;
channel side slopes will be not steeper than 2:1.
Structural Backfill - Backfill material shall be of the type and
quality conforming to that specified for the adjoining fill
material. The material shall be placed in maximum six
inch lifts and hand compacted to equal or exceed the density
of the adjoining fill.
INFORMATION TO BE SUBMITTED FOR APPROVAL:
Sediment Basin designs submitted for review to the Soil Conser-
vation District and construction plans submitted to the responsible
county agency will include the following:
a. Specific location of the dam
b. Plan view of dam and the storage basin
c. Cross section of dam and emergency spillway; profile
of emergency spillway
d. Runoff calculations for 10-year storms
e. Calculations showing design of pipe and emergency spillway
f. Storage Computation (stated in acre feet)
1. Total required (acre feet)
2. Total available (acre feet)
3. Level of sediment when storage drops below
0.2 inches per acre of drainage area
153
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NOTE:
Items d through f above may be submitted using a design
data sheet similar to that shown in Appendix A-4.
SEDIMENT BASIN CONSTRUCTION AND MAINTENANCE CRITERIA:
The following are critical to successful installation and operation
of Sediment Basins:
a. Locate the dam to provide maximum volume capacity
for silt behind the structure.
b. Prepare the dam site by adequate clearing of vegetation
and removal of topsoil before beginning dam construction.
c. Level the bed for the pipe spillway to provide uniform
support throughout its entire length under the dam.
d. Securely and rigidly fasten the collar connecting the riser
to the barrel (as well as collars connecting sections of the
barrel) of the pipe spillway; insure a watertight bottom on
the riser; hand tamp fill under shoulders and around the
pipe; insure that outlet invert of pipe spillway is not more
than one foot above streambed.
e. Place the fill in not more than six-inch lifts compacted by
construction equipment. A minimum of two (2) feet of hand
compacted backfill shall be placed over the pipe spillway
before crossing it with construction equipment. Fill materials
should be free from roots, woody vegetation, oversize
stones, rocks, or other objectionable material. Frozen
material should not be used.
f. Construct emergency spillway as per design on undisturbed
soil (not on fill). Design width and entrance and exit channel
slopes are critical to the ability of the emergency spillway
to successfully protect the dam with a minimum of erosion
hazard in the spillway channel.
g. Stabilize embankment and emergency spillway by treatment
(lime and fertilizer) sodding or seeding and mulching.
h. When trap efficiency drops below 0. 2 inch per acre of
drainage area, the sediment basin should be cleaned out to
store its original capacity.
154
-------
MAINTENANCE:
Inspect after each storm. Remove sediment each and every time
the structure capacity has been reduced by the factor determined
in structure design. Sediment must be disposed of or stabilized
in a manner that will preclude its return to downstream areas
during storm runoff events.
FIGURE B-45. Sediment retention structure - small, less than
1/4 acre
155
-------
FIGURE B-46.
Sediment retention structure - Large, 4 acres.
Will be converted for recreational use after
development is complete.
FIGURE B-47. Sediment retention structure - 1 acre
156
-------
FIGURE B-48. Sediment retention structure - maintenance
past due
FIGURE B-49. Sediment retention structure now requiring
maintenance (cleanout)
157
-------
NOTES
158
-------
STRAW BALE SEDIMENT BARRIERS
Technical Information
DEFINITION:
Straw Bale Sediment Barriers are temporary berms, diversions,
or other barriers that are constructed of baled straw.
OBJECTIVE:
Straw Bale Sediment Barriers retain sediment on-site by retarding
and filtering storm runoff.
WHERE USED:
The barriers are used at storm drain inlets; across minor swales
and ditches; as training dikes and berms; along property lines;
other applications where the structure is of a temporary nature
and structural strength is not required.
CONSTRUCTION RECOMMENDATIONS:
a. Bales bound with nylon or wire are more durable than
twine bound bales.
b. Bales should be anchored to the ground with steel pins,
fence posts, rebars, wood pickets, etc. Two anchors
per bale are required.
c. Bales must be installed so that runoff cannot escape
freely under the bales.
MAINTENANCE:
Bales are target for vandals; daily inspection required. They
must be replaced when rotten or disintegrating. Remove
sediment from bale structures after each storm.
159
-------
'*^£;&ti&&** ^
FIGURE B-50. Straw bale structure at storm drain inlet
- **,
FIGURE B-51. Straw bale structure at toe of sediment
retention structure (tidal)
160
-------
• „* ."** .'
•
* -v
FIGURE B-52. Straw bale structure on property line
*VV *'
FIGURE B-53. Straw bale structure at storm drain inlet
161
-------
NOTES
162
-------
APPENDIX C
FIBER MULCHES, MULCH BLANKETS, AND NETTINGS
163
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EXCELSIOR BLANKET
Technical Information
PRIMARY USAGE:
The Excelsior Blanket is a protective blanket used in the establish-
ment of vegetation in critical areas. As a mulching product it
conserves soil moisture, serves as an insulator against intense
solar insolation, dissipates energy from falling raindrops, and
reduces erosion caused by overland flow. The use of a reinforcing
weave, the intertwined nature of the excelsior, and the fact that
the blanket is secured to the soil by metal staples make this
product resistant to erosion by concentrated storm runoff. It can,
therefore, be used in critical areas such as swales, ditches, steep
slopes, highly erodible soil, etc.
DESCRIPTION:
The Erosion Control Excelsior Blanket consists of a machine
produced mat of curled wood excelsior of 80 percent eight inch
or longer fiber length. It is of consistent thickness and the fiber
is evenly distributed over the entire area of the Blanket. The top
side of each Blanket is covered with a 3" x 1" weave of twisted
Kraft paper or biodegradable plastic mesh that has a high wet
strength. Blankets are smolder resistant and contain no chemical
additives. The Blankets are available in 3' x 150' rolls and in
4' x 180' rolls. They are secured to the soil by the use of heavy
duty wire staples.
INSTALLATION INSTRUCTIONS:
Each specific site may require some modification or variation
from the general criteria listed below. Manufacturer technical
representatives or conservation specialists experienced in the
use of this product should be consulted for guidance. In general,
the Blanket is rolled out on the seeded area to be protected and is
stapled into place. Suggested staple application rate, under normal
conditions, is five staples per six linear feet of Blanket, placed
two along each side and one in the middle. Where more than one
Blanket is required they are butt-joined and securely stapled.
Care should be exercised to ensure that the Blanket is placed with
the weave side up. When used in areas of concentrated flow they
must be extended laterally to an elevation that is several inches
above the elevation of the design high flow. This precaution will
discourage gully and rill formation along the margins of the
installation. An even greater degree of success is often attained
164
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if erosion checks (Appendix B) are used in conjunction with the
Excelsior Blanket.
PRODUCT INFORMATION SOURCE:
American Excelsior Company
P.O. Box 5067, 850 Avenue H East
Arlington, Texas 76011
(Erosion Control Excelsior Blanket)
v..
FIGURE C-l. Excelsior blanket and staple
165
-------
FIGURE C-2. Driving staple to anchor excelsior blanket
NOTES:
166
-------
FIBER GLASS MATTING
Technical Information
PRIMARY USAGE:
Erosion check (Appendix B) construction is one of the most common
applications of Fiber Glass Matting. In its various forms, it is
also used in landscaping as a filter-separator between topsoil and
gravel drainage beds, and as a mulch for seedbeds and for other
applications. In this document it is only considered in its appli-
cation for use in the construction of erosion checks and as a mulch
for seedbeds.
DESCRIPTION:
Fiber Glass Matting is composed of flexible fiber glass that is
made of inorganic materials that will not rot, corrode, or burn.
It is supplied in rolls of material 1/2-inch thick. Roll width can
be variable from two to six feet. Roll length varies from 100 to
150 feet.
INSTALLATION INSTRUCTIONS:
At locations where erosion checks are planned a trench is dug
across the ditch, swale, slope, etc. See Erosion Check (Appendix
B) for trench details. Place fiber glass matting in an "L" shape
with the long dimension up; staple matting against the vertical side
of the trench and along the bottom sufficiently to hold it in place.
Backfill, tamp, and trim matting flush with the surface.
Where long-term resistance to erosive forces is desired in con-
junction with vegetation, Fiber Glass Matting can be used as a
mulch blanket. It is applied in a similar manner to the Excelsior
Blanket. (See this Appendix for details).
PRODUCT INFORMATION SOURCE:
Certain-Teed Products Corporation
Gustin-Bacon Division
3050 Fairfield Road
P.O. Box 15079
Kansas City, Kansas 66115
(Ultracheck®)
167
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PPG Industries, Inc.
Fiber Glass Division
One Gateway Center
Pittsburgh, Pennsylvania 15222
(Topsoil Separator)
FIGURE C-3. Fiber glass mat at culvert invert
168
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GLASSROOT®
Technical Information
PRIMARY USAGE:
GLASSROOT® is a mulch product for use on newly seeded areas. As
a mulching product it conserves soil moisture during dry periods,
serves as an insulator against intense solar energy, dissipates
energy from falling raindrops, and reduces erosion caused by
overland sheet flow.
DESCRIPTION:
GLASSROOT® is a fiber glass product. Its appearance is somewhat
similar in appearance to the "angel hair" used in Christmas
decorations. It consists of a bundle of continuous fiber glass
rovings that are packaged in 35 pound units. It is dispensed by
means of a simple application kit that consists of a light metal
container complete with shoulder strap for easy carrying, a valve
and nozzle, and a 50-foot hose. The hose is connected to an air
compressor unit operating at 50 to 60 pounds pressure. As
GLASSROOT® is fed into the nozzle, compressed air propels and
separates the strands of glass fibers, spreading them evenly over
the area. GLASSROOT® is inorganic and will not react or decompose
when exposed to water, sunlight, or chemicals found in the soil.
INSTALLATION INSTRUCTIONS:
Conduct normal seeding operations. Apply GLASSROOT® at the
rate of about 35 pounds per 150-200 square yards. This rate can
be varied depending upon individual site conditions and as experi-
ence with the product is acquired. Tacking is generally not
required because the fiber glass strands tend to "attach" to every
tiny surface irregularity and thereby anchor the mulch. Since
this product is nonbiodegradable, it provides reinforcement to
turf. Foot traffic by animals and humans on mulched areas should
be discouraged until such time as the mulch has become an integral
part of the turf.
PRODUCT INFORMATION SOURCES:
PPG Industries, Inc.
Fiber Glass Division
One Gateway Center
Pittsburgh, Pennsylvania 15222
169
-------
T' ** '.*. if -It
.*--.. -sv.
.i« ^vd^JB^rVi.
FIGURE C-4. GLASSROOT® application
FIGURE C-5. GLASSROOT® in place
170
-------
FIGURE C-6. GLASSROOI® in place - vegetation starting
NOTES:
171
-------
JUTE NETTING
Technical Information
PRIMARY USAGE:
Jute Netting is used in the establishment of vegetation in critical
areas. As a mulching product, it conserves soil moisture, serves
as an insulator against intense solar insolation, dissipates energy
from falling raindrops, and reduces erosion caused by overland
flow. The thick strands and heavy weave enable this product to
withstand the higher flow velocities associated with critical swales,
ditches, median strips, etc.
DESCRIPTION:
Jute Netting is a heavy woven jute mesh of rugged construction.
It is constructed of undyed and unbleachedtwisted jute fibers. It
can be treated to be smolder resistant. It is commonly available
in individual rolls, 225 feet long and 4 feet wide. Each roll
contains 100 square yards and weighs approximately 90 pounds.
INSTALLATION INSTRUCTIONS:
Prepare seedbed according to local specifications. Seeding may
be split so that one-half of seed is sown after the jute has been
applied. Each specific site may require some modification or
variation from the general criteria listed below. Manufacturer
technical representatives or conservationists experienced in the
use of this material should be consulted for specific guidance.
In general, start laying the thatching from the top of the channel
and unroll downgrade so that one edge of the strip coincides with
the channel center. Lay a second strip parallel to the first on the
other side of the channel and allow a two-inch overlap. If one roll
of thatching does not extend the length of the channel, continue
downhill with additional rolls.
Bury the top end of the jute strip in a trench four inches or more
deep. Tamp the trench full of soil. Reinforce with a row of
staples driven through the jute about four inches downhill from the
trench. These staples should be about 10 inches apart. Then
staple the overlap in the channel center. These staples should be
4 to 10 feet apart. The outside edges may be stapled similarly
at any time after the center has been stapled. Closer stapling
along the sides is required where concentrated water may flow into
the channel.
172
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Succeeding strips of thatching, farther down the channel, are
secured in a similar manner.
Where one roll of thatching ends and another roll begins, the end of
the top strip overlaps the trench where the upper end of the lower
strip is buried. Make the overlap at least four inches and staple
securely. If the ends and edges of the strips of thatching are
securely stapled, stapling in the strip middles may be 10 feet
apart or omitted entirely.
At any point the thatching may be folded for burying in slit trenches
and secured as were the upper ends. This checks water flow and
erosion that may begin under the matting. It also gives improved
tie-down.
Insure contact between thatching and soil by rolling after laying,
stapling, and seeding is complete. Perfect contact is vital to keep
water flow over, not under, the jute.
After job completion, make sure the thatching is in contact with
the soil at all places and that critical areas are securely stapled
down.
Hairpin-shaped wire staples, No. 8 gauge; 6, 8, and 10 inches long
have been used. The longer staples are used in loose or wet soil.
Wire staples are better than wooden pegs because the staples can
be driven flush with the matting. Wooden pegs extend above the
thatching and may catch trash that diverts water flow out of the
thatch-protected channel. Wooden pegs may also set up a damaging
turbulence.
The use of erosion checks (Appendix B) in conjunction with jute is
strongly recommended.
PRODUCT INFORMATION SOURCE:
Belton Bagging Company
P.O. Box 127
Belton, South Carolina 29627
Bemis Company, Inc.
P.O. Box 12224 Soulard Station
2400 South Second Street
St. Louis, Missouri 63104
Ludlow Corporation
Textile Division
Needham Heights, Massachusetts 02194
173
-------
FIGURE C-7. Jute netting being installed
FIGURE C-8. Jute netting - close-up
174
-------
FIGURE C-9. Jute netting over straw mulch in a drainageway
NOTES:
175
-------
MULCH BLANKETS
Technical Information
PRIMARY USAGE:
Mulch Blankets are used in the establishment of vegetation in
critical areas. As a mulching product they conserve soil moisture,
serve as insulators against intense solar insolation, dissipate
energy from falling rain, and reduce erosion caused by overland
flow.
DESCRIPTION:
Conwed Turf Establishment Blanket is a composite of all new
cellulose fibers that are bonded with a water soluble binder that
is noninjurious to seed germination or growth. The bound material
forms a homogeneous mat. An extruded, oriented plastic net with
approximate 1/4-inch by 1/4-inch mesh openings is bonded to the
top surface of the mat. The blanket is supplied in rolls
wide and 200 feet long. The material weighs approximately 25
pounds per 1000 square feet. After application and saturation
by rain, the fibrous blanket loosens to form a thick mulch cover.
This cover and the underlying seed and soil is then held in place
by the mesh plastic net. The fiber mulch blanket conforms to the
surface to prevent erosion by wind and water.
Swif-Gro is a lightweight, all cotton woven (leno weave), open
mesh fabric laminated to cellulose tissue. Tensile minimum is
45 pounds in the wrap direction and 35 pounds in the filling direction.
Roll length is approximately 500 yards. Roll width is 75 inches,
plus two inches, minus one inch. One roll weighs 170 pounds +
10 percent. ~~
INSTALLATION INSTRUCTIONS:
Specific sites may require some modification or variation from
the general criteria listed below. Manufacturer technical repre-
sentatives or conservation specialists experienced in the use of
this product should be consulted for guidance. Both materials
are designed to be unrolled and stapled over prepared, seeded
soil surfaces. Where more than one roll of material is required,
sufficient overlap should be provided to ensure against separation
at these seams. Neither material should be stretched tight.
They should be applied so as to conform to surface irregularities
and must be in continuous contact with the soil surface. Material
should be secured in depressions with additional staples. Care
176
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must be exercised to ensure that the Conwed Turf Establishment
Blanket is installed with the plastic net on top. When used in
areas that experience concentrated overland flow, fabric blankets
must be extended laterally to an elevation that is several inches
above the elevation of the design high flow. The use of erosion
checks (Appendix B) in conjunction with these products is strongly
recommended.
PRODUCT INFORMATION SOURCE:
Conwed Corporation
332 Minnesota Street
St. Paul, Minnesota 55101
(Conwed Turf Establishment Blanket)
Southern Phenix Textiles, Inc.
Box 1108
Phenix City, Alabama 36867
(Swif-Gro)
FIGURE C-10. Mulch blanket being installed
177
-------
FIGURE C-ll. Mulch blanket being stapled
NOTES:
178
-------
NETTING
Technical Information
PRIMARY USAGE:
Netting is used as a means by which natural or synthetic fiber
mulch can be securely anchored on seeded areas or areas temporarily
stabilized with mulch on which conventional mulch tacking products
(asphalt, chemicals, etc.) are judged to be insufficient. This
approach to tacking mulch is often used on very steep areas and
on odd shaped areas, especially around structures. Nettings are
also used to reinforce newly placed turf that may be subjected to
severe runoff velocities before the root zone has matured to the
point where turf structure alone can withstand the anticipated
stress.
DESCRIPTION:
Several products are on the market and compostions range from
tightly twisted Kraft paper yarns to polypropylene oriented plastic
to fiber glass scrim. All are lightweight. The Kraft paper yarns
are biodegradable. The polypropylene is ultraviolet sensitive and
gradually disintegrates in the presence of sunlight. The poly-
propylene net and fiber glass scrim will not support combustion.
All products are marketed in rolls. Roll widths range from 3. 75
to 15 feet. Lengths range to 2500 feet.
INSTALLATION INSTRUCTIONS:
Generally these products are unrolled and stapled on areas that
have been mulched with natural and synthetic fiber mulch. Staple
placement is not as critical in securing netting on mulch as it is
with some of the other products discussed in this Appendix.
Guidance can be secured from manufacturer's technical represen-
tatives or conservation specialists familiar with the use of these
products.
When used to anchor newly placed sod, stapling becomes more
critical and staple placement on 36-inch centers is often used.
Netting with small openings is susceptible to heaving as the turf
matures.
179
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PRODUCT INFORMATION SOURCE:
Bemis Company, Inc.
P.O. Box 12224 Soulard Station
St. Louis, Missouri 63157
(Mulch net - Kraft paper)
Conwed Corporation
332 Minnesota Street
St. Paul, Minnesota 55101
(Conwed Erosion Control Netting)
PPG Industries, Inc.
Fiber Glass Division
One Gateway Center
Pittsburgh, Pennsylvania 15222
(Fiber glass scrim)
*^9JSg^&*&>
• ' V *f,'i •»" **** • * ' * ""*W""'\ .*J
^%v,,^5;'. '*"' ,.'/'• -V^^,^-'. .
^ ^'-'-dlSBSHBfesM ' ^"^^SCwKi .
x? '
fj^Hf5/:>'- t "-1*
FIGURE C-12. Plastic net over fiber glass roving - close-up
180
-------
FIGURE C-13. Plastic net (on roll) ready for installation
in critical area
NOTES:
181
-------
PLASTIC FILTER SHEET
Technical Information
PRIMARY USAGE:
Plastic Filter Sheets are used as a replacement for graded filter
systems and filter blankets in conjunction with many hydraulic
structures.
DESCRIPTION:
Plastic Filter Sheet is a cloth woven of polypropylene monofilament
yarns. The cloth is 18 mils thick, weighs 7.35 ounces per square
yard, and is not affected by salt water. Porosity is 14b cfm and
the cloth is strong and abrasion resistant. It loses no strength
when wet and stretches 25 percent before breaking. It is available
on rolls of 50 to 200 foot lengths and 6 to 84 foot widths, it can
be fabricated with grommeted edges. The material is secured to
the soil surface with metal securing pins and staples and with fiber
glass rods.
INSTALLATION INSTRUCTIONS:
Each specific site may require some modification or variation of
the general criteria listed below. Manufacturer technical repre-
sentatives or specialists experienced in the use of this product
should be consulted for guidance. In general, the material is
rolled out onto the prepared surface and secured with specially
designed pins, staples, or rods. Where more than one sheet is
required, they should be lap jointed to ensure continuous coverage
of the area to be protected. When in place, the succeeding layer of
materials ie, gravel, rock, can be placed on the filter sheet. Heavy
and/or sharp material should be placed with care in order that the
integrity of the sheet can be maintained.
PRODUCT INFORMATION SOURCE:
Carthage Mills Incorporated
Erosion Control Division
124 West 66th Street
Cleveland, Ohio 44102
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STRAW OR HAY
Technical Information
PRIMARY USAGE:
Straw or hay is a mulch product for use on newly seeded areas.
In this capacity, it conserves soil moisture during dry periods,
dissipates energy from falling raindrops, serves as an insulator
against intense solar energy, and reduces erosion caused by overland
sheet flow. It is also used as a temporary measure to protect bare
soil areas that have not been seeded. The latter practice is appli-
cable only for relatively short periods of time or until the next
seeding season has been reached.
DESCRIPTION:
Generally, unweathered, unchopped small grain straw is used.
Wheat straw is preferred. Hay can also be used.
INSTALLATION INSTRUCTIONS:
Straw or hay mulch can be applied by hand spreading (shaking) on
small plots and by mulch blowing equipment on larger areas. It is
applied at rates of one to two tons per acre. Straw and hay mulch
should be tacked to insure against excessive losses by wind and
water. Liquid and emulsified asphalt is the most commonly used
mulch tack. However, other chemicals (Appendix A) and mulch
netting products (Appendix C) are available for use as mulch tacks.
Mulch anchoring tools can also be utilized to anchor straw and hay.
This equipment consists of a series of notched discs which punch
and anchor the mulch material into the soil. Soil must be moist,
free of stones, and loose enough to permit disc penetration to a
depth of two to three inches if this mulch anchoring technique is to
perform in a satisfactory manner.
183
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^Wrnff^^-
im^
«i
•
FIGURE C-14. Straw mulch being applied by mulch blower
FIGURE C-15. Large straw mulching operation
184
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FIGURE C-16. Asphalt being used to tack straw mulch
NOTES:
185
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WOODCHIPS
Technical Information
PRIMARY USAGE:
Woodchips are used as a temporary or interim erosion control
technique to protect bare soil areas that have not been seeded.
They are also used as a mulch product on newly seeded areas.
In this capacity, they conserve soil moisture during dry periods,
dissipate energy from falling raindrops, serve as insulators
against intense solar insolation, and reduce erosion caused by
overland sheet flow. Woodchips may also be used on pathways
and to reinforce leaf mold, duff, etc., in wooded areas that are
to be preserved.
DESCRIPTION:
Chips of wood are produced by processing tree trunks, limbs,
branches, etc., in woodchipping machines. The chips are
placed by blower back on the site from which they originate or
are placed in trucks for transport to other sites where they are
spread for use.
INSTALLATION INSTRUCTIONS:
As a temporary technique on unseeded areas, the chips are placed
by machine or spread by hand tools. Application rates range from
4 to 6 cubic feet of woodchips per 100 square feet of area. This
application rate is ample to protect bare soil under normal
conditions. If intensive foot or vehicle traffic is anticipated, this
rate may be increased to the point where woodchip depths of
several inches are attained. This very heavy application rate is
particularly applicable to yard areas adjacent to homes under
construction if autos and light trucks drive and park in the yard area.
As a mulching product on newly seeded areas, woodchips may be
placed by machine blower or by hand from stockpiles. Application
rates of 60-100 cubic yards per acre are commonly recommended.
Mulching with woodchips has proven successful when used with late
fall seeding operations that require protection over winter. Exper-
imental work is needed to perfect seed mixtures for this type of
operation. However- the wood chip mulch has proven to be satis-
factory under these conditions.
As more interest in preserving "natural" woodland conditions on
construction sites is expressed, the use of woodchips to supplement
existing leaf mold, duff, etc., is accelerating. Chips that cannot
186
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be utilized in mulching operations can safely be returned to the
forest floor to supplement existing organic cover. This technique
is beneficial in that it upgrades the woodland surface area and
provides a means to recycle rather than dispose of a natural by-
product.
FIGURE C-17.
Woodchips - application rate is 4 cubic feet
per 100 square feet of area
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,/"••*. •• - '.;.-* ...
"• *"w™*- - - -•-" " . •"•" . ' ; -; '• .:
aai
FIGURE C-18. Walkway of woodchips
FIGURE C-19. Spreading woodchips on homesite
188
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NOTES
189
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WOOD FIBER MULCH
Technical Information
PRIMARY USAGE:
Wood fiber mulch is specifically designed for use as a hydraulically
applied mulch that aids in the establishment of turf or other seeded
or sprigged ground covers. As a mulching product.it conserves
soil moisture, serves as an insulator against intense solar insolation,
and dissipates energy from falling raindrops.
DESCRIPTION:
Wood fiber mulch is a natural, short fiber product, produced from
clean, whole wood chips. A nontoxic dye is used to color the mulch
green in an effort to aid visual metering in its application. It is
evenly dispersed and suspended when agitated in water, and when
applied uniformly on the surface of the soil, the fibers form an
absorbent cover, allowing percolation of water to the underlying
soil. Wood fiber mulch has the following physical properties:
Property Nominal Value
Moisture Content 9. 0-12. 0% + 3. 0%
Organic Matter (Oven-Dried Basis) 99. 2-99. 6<#T+_ 0. 2%
Ash Content 0. 4-0. 8% + 0. 2%
Water Holding Capacity at least
(grams of water/100 grams of fiber) 1080-1150 grams
Wood fiber mulch contains no growth or germination inhibiting
factors. In hydroseeder slurries, it is compatible with seed, lime,
fertilizer, etc. It is packaged in Kraft paper bags containing 50
pounds each.
INSTALLATION INSTRUCTIONS:
Wood fiber should be applied by hydroseeder at rates of 1000-1500
pounds per acre. It is introduced into the slurry tank after the
proportionate quantities of seed, fertilizer, etc., have been
introduced. The components are agitated into a well mixed slurry
and are sprayed onto the sites or plots to be seeded.
190
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PRODUCT INFORMATION SOURCES:
CONWED® HYDRO MULCH
Conwed Corporation
332 Minnesota Street
St. Paul, Minnesota 55101
WEYERHAEUSER SILVA-FIBER®
Weyerhaeuser Company
Fiber Products Department
Tacoma, Washington 98401
FIGURE C-20. Wood fiber (short fiber) being applied in
hydroseeder slurry
191
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•''-
FIGURE C-21. Wood fiber mulch in place (close-up)
NOTES:
192
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APPENDIX D
SPECIAL EROSION AND SEDIMENT CONTROL PRACTICES
193
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CONSTRUCTION COORDINATION
Technical Information
One of the primary rules for a good sediment and erosion control plan
is that the minimum area should be exposed for the minimum amount
of time. The chances for realization of these minimums can be improved
by good construction coordination techniques.
Construction coordination has been a fact for many years. We are now
faced with the reality of incorporating another parameter into the con-
struction coordination effort. The new factor is sediment and erosion
control. Many builders and developers no longer "rough grade" far in
advance of subsequent construction activities. Rough grading in late
fall or winter, without the implementation of an acceptable plan to reduce
erosion and sediment, is being discouraged.
The advent of total underground utility construction requires that this
phase of construction activity be included in any attempt to reduce sedi-
ment and erosion by the closer coordination of construction activities.
Consider, for example, the development where storm sewer, water,
sanitary sewer, electricity, telephone, and gas utilities are all con-
structed subsurface. Construction practice incorporates very little
coordination of the installation of these services. There is a great need
to shorten the time period from the start to the finish of underground
construction. Argument can be made that simultaneous installation is
not possible. If this argument is accepted, the questions of how much
time lapse is acceptable between the completion of one and the start of
the next and, can this period be shortened by the closer coordination of
underground construction effort must be asked.
Another question that is being raised is why each service must be in a
separate trench. One school of thought suggests that the "utilidor"
concept, where more than one service is combined in a common trench,
be adopted in an effort to disturb smaller areas or to disturb a given
area for a shorter period of time. The opposition group suggests that
this approach is not acceptable in development construction.
Unfortunately, no simple answer exists to these questions. However,
answers will be forthcoming if these questions are seriously considered
and if they are incorporated into the coordination of future construction
activities.
NOTES
194
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MULCH ANCHORING
Technical Information
DEFINITION:
Mulch Anchoring is the anchoring of long fiber mulch by the use
of mechanical equipment rather than by chemical tacking or the
use of confining nettings.
DESCRIPTION:
A mulch anchoring tool is often used to secure straw and hay
mulch. It is composed of a series of notched discs which anchor
the mulch by punching it into the soil. The same effect can be
achieved on a limited basis by the use of a tracked vehicle equipped
with grouser bars (treads) that are at least 1-1/4 inches long.
NOTES:
In order for mulch anchoring to be effective, the soil must be
moist, free of stones, and loose enough to permit disc penetration
to a depth of 2-3 inches. On slopes the mulch anchoring tool
should be used on the contour to secure maximum erosion control.
Since the mulch anchoring tool is limited to use on those slopes
upon which a tractor can be safely operated on the contour, the
use of a crawler tractor with long treads should be considered
on steeper slopes. Soil conditions must be the same for either
approach. The crawler should work up and down the slope in
order that the tread tracks will be across the slope.
On critical slopes, the combination of mulch anchoring and mulch
tacking is recommended so that the seeding operation will have the
best possible chance of succeeding.
NOTES
195
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PUMPED WATER MANAGEMENT
Technical Information
DEFINITION:
Pumped Water Management is the control of water being pumped
on construction projects so that it will not be deleterious to the
environment by eroding soil and providing sediment to downstream
areas.
DESCRIPTION:
The only effort required to accomplish proper management of
water being pumped on construction sites is to ensure that it is
discharged on a stabilized area. This may require the use of
extra hose or pipe to reach a stable outlet.
NOTES:
Water being pumped from excavations on construction sites is
seldom considered as a source of sediment pollution. However,
if the discharge is to a fill slope, highly erodible soil, etc., it
unfortunately qualifies. Consideration must now be given to
this potential source of erosion and sediment production.
An obvious answer is to pump to a storm sewer. Since storm
sewer construction is usually completed before other work begins,
this option is generally open. Another possibility is to carry the
water by hose to an adjacent water course.
In any event, pumped water discharge onto fill slopes, spoil piles,
highly erosive soils, etc., should not be tolerated.
196
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FIGURE D-l. Water being pumped from an excavation and
being discharged onto a spoil pile
- "
It;
FIGURE D-2. Same area as Figure D-l. Pumped water should
be discharged to completed storm drain.
197
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FIGURE D-3. Pumped water being discharged to stable area
(surfaced street) rather than to bare soil
NOTES:
198
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ROUGHNESS AND SCARIFICATION
Technical Information
DEFINITION:
In the context of this document, roughness means the uneven or
bumpy condition of the soil surface. Scarification is the process
of loosening or stirring the soil to shallow depths without turning
it over.
DESCRIPTION:
Roughness associated with earth moving activities is typified by
surfaces that have not been smooth graded. Scarification is
commonly thought of as a means by which rock and/or soil is
loosened by bulldozers equipped with ripper attachments. For
the purposes of this discussion, scarification is accomplished by
smooth grading an area by means of a bucket (front end loader)
equipped with teeth. " It can also be created by the grouser bars
on crawler tractors.
NOTES:
For the purposes of sediment and erosion control, roughness and
scarification can be utilized to reduce the production of sediment
and to aid in the establishment of other erosion control practices.
As an example, consider a building site that has been temporarily
smooth graded with a front end loader equipped with a toothed
bucket. If the grading is up and down slope, runoff and erosion
are encouraged by the scarification marks. If, however, the
grading is accomplished on the contour or across the grade, the
scarification marks will tend to retain or retard moisture.
If the surface prepared in the above manner is to be seeded or
sodded, the scarification marks take on even greater importance.
On a seedbed, the marks trap and retain seed and moisture. This
seed is often covered by soil being carried downslope by runoff
and may be the only areas in which seed remains after a rather
severe storm. If the seed thus trapped is a turf forming grass,
it may be sufficient to establish an acceptable vegetative cover
without requiring a reseeding program.
Sod laid on steep slopes cut in fine grained soil will often fail to
bond with the soil surface and slip to the bottom of the slope if
the surface is smooth graded. Scarification marks across the
slope will aid in keeping sod in place until its root system has
formed an adequate bond with the soil. Nutrients placed under
199
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the sod will also be retained in the roughened area better than
if the soil surface is absolutely smooth.
Another example is the slope that is to receive a mulch (woodchips)
to protect it from excessive erosion between seeding seasons. If
the slope has been scarified, the woodchips will adhere to the soil
surface with greater tenacity than they will to a smooth graded
surface.
Topsoil is often spread on slopes by tracked dozers. If the slope
is finished up and down slope, or if a diversion dike (Appendix B)
is constructed, the tracks created by the grouser bars on the
tractor will improve the roughness of the slope and subsequent
seeding or mulching operations will be aided by this roughness.
Infiltration of rainfall is enhanced when a surface is left in a rough
condition. This factor is also important when erosion, sediment,
and storm runoff controls are planned and implemented together
in a total conservation program.
Many other examples are worthy of inclusion in this appendix, but
these have been chosen in an effort to point out the advantages of
a rough or scarified surface over one that has been smooth graded.
»M.
FIGURE D-4. Scarification up and down slope aids erosion
200
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ft
* *V
FIGURE D-5. Scarification across slope aids erosion control
FIGURE D-6. Serrated cut - a type of roughened slope
201
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FIGURE D-7. Scarification on slope behind homesites
NOTES:
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STUMP REMOVAL
Technical Information
DEFINITION:
Stump Removal is the removal of the stumps of trees that have
been cut down to facilitate construction activities, to improve
the woodland setting, or because of tree mortality on completed
lots or developments.
DESCRIPTION:
The disposition of tree stumps may take several forms. Physical
removal using bulldozers, front end loaders, etc., is common.
Blasting is still used in some instances. Chemicals are also used
when immediate removal is not required.
NOTES:
The removal of stumps by heavy equipment exposes soil to erosion.
With the advent of antiburning laws in many areas, stumps must
be removed to landfill sites for burial. These two facts make
physical removal undesirable. If the removal is required after
construction and landscaping have been completed, it is even
more undesirable.
An alternative exists in the form of a machine called a stump
cutter. It consists of a toothed metal drum that rotates at high
speed. When held in contact with the stump, it reduces the stump
to chips. The machine can be operated to a depth of about 6 inches,
depending upon soil conditions. After the stump has been removed,'
the woodchips can be used to fill the void and no scar is left to
backfill.
The stump cutter is generally available on a contract basis for
small jobs. Information may be obtained from local soil and
water conservation districts; federal, state, and local forestry
specialists; and tree surgeons.
203
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FIGURE D-8. Stump cutter
, ,
*
FIGURE D-9. Stump cutter removing stump
204
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FIGURE D-10. Stump partially removed by stump cutter
NOTES:
205
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TRAFFIC CONTROL
Technical Information
DEFINITION:
Traffic Control is the control of construction traffic (heavy equip-
ment, service vehicles, autos, etc.) during the development of a
parcel of land.
DESCRIPTION:
Experience has shown that indiscriminate traffic travel is
deleterious to any sediment and erosion control program that is
instituted at a construction site. The damage caused often in-
fluences vegetation and other natural features that would normally
endure long after construction operations are complete. An effort
must, therefore, be made to eliminate construction traffic from
areas where its presence is only for convenience and to control it
in other areas. Conversely, any effort to restrict construction
traffic from certain areas must be tempered with sound judgment.
The work to be done must not be seriously impaired. Avenues
or corridors that are required during construction must be estab-
lished early in the planning phase, and construction techniques
must be accurately anticipated so that a workable traffic control
scheme can be prepared.
Much is still to be learned regarding this phase of development.
The notations that follow can undoubtedly be supplemented by
many more. They are presented in an effort to bring this often
serious problem to light so that it can be considered in the pre-
paration of sediment and erosion control schemes in the future.
NOTES:
When an area is to be "phase developed" there will often be at
least one rather extensive area that will not be immediately
graded. If it is vegetated, this vegetation should be maintained as
long as possible. If equipment travel is anticipated across this
area, a corridor large enough to accommodate any equipment
that will be used on the job should be established. Vehicles should
not be allowed to drive over the whole parcel. Each vehicle does
not have to break a new track across the area. Any traffic restric-
tions will have to be clearly explained to all supervisory personnel
in order that they can relay the word to every equipment operator
on the job.
206
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The above is especially true if an area happens to be wooded and
scheduled for preservation. It is also true of areas that have been
seeded to establish cover for sediment and erosion control. Fencing
may be required to achieve these goals.
On large (1/3-acre or larger) wooded home sites, there is seldom
a need for equipment travel on the back portions of lots. Trees
have their best chance for survival here, and equipment must be
excluded from these areas if these trees are to be given the best
protection. If it is required to travel from place to place, a route
should be established that will stress the area as little as possible.
This may require using the roadway "around the block" rather
than a direct route through "the back lot. "
In wooded areas indiscriminate traffic travel can often be avoided
by ensuring that a corridor is available for use. Consider the
example where trees have not been removed beyond the top of cut
slopes along roadways. Underground utility construction will
often completely close the road to other traffic, and other equipment
will "cut through the woods. " If the clearing were extended another
10-15 feet along the top of the cut slope, an alternate corridor
would be provided for use when the roadway is temporarily closed.
This extra clearing effort will remove trees that probably could
not survive immediately adjacent to the cut slope even if they were
allowed to remain.
Vegetation on floodplains must be protected from traffic. These
"filter strips" often trap enormous amounts of sediment moving
off of construction sites. Their integrity must be maintained if
they are to continue to function. In the event that floodplain travel
is required, a corridor must be located and travel must be re-
stricted to the corridor.
The absolute avoidance of equipment travel in drainageways is
required. Crossings should be established where their existence
can be protected. Indiscriminate crossing by equipment should
not be allowed. This is especially true in constructed waterways
that have been stabilized against erosion and sediment production.
207
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C'1
It* €
'. ' ' !
. , Of. f«
«#-"** ,*
FIGURE D-ll. RiUs in equipment tracks
: ;
FIGURE D-12. Road completely closed by sanitary sewer
construction
208
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FIGURE D-13. Two routes (one is a convenience route) to
same location
FIGURE D-14. Area completely denuded by equipment travel
209
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FIGURE D-15. "Convenience" route through a stand of trees
marked for preservation
NOTES:
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TREE PROTECTION
Technical Information
DEFINITION:
Tree Protection is the protection of trees from damages incurred
during construction activities.
DESCRIPTION:
Tree protection can involve protection of crowns, trunks, and
root zones from direct damage from construction equipment.
The alteration of the water table and conversion of a woodland
environment to a parkland environment can also jeopardize the
well-being of trees selected for retention on the property being
developed. The actual selection of specimens to be saved has
an influence on tree preservation in general.
NOTES:
There are many items to be considered under this category. No
priority is set regarding their relative importance since each can
be of prime importance in the appropriate situation. However,
since trees protect the soil from erosion and sediment production,
they must be preserved, whenever possible, for erosion control
as well as for aesthetic reasons. Some concern is being given to
tree preservation as is evidenced by the fences that are often
erected around trunks. This protection is generally insufficient,
however, unless the fence is erected at the drip line. Generally,
a tree's root system extends as far in a lateral direction under-
ground as do the branches of the tree above ground and any pro-
tective barrier should be erected to protect the root zone as well
as the trunk and branches. Protection inside the drip line is
required to prevent against "barking" the trunk, compaction of
soil over feeder roots, physical damage to shallow root systems,
and the stockpiling of spoil and construction material on the root
zone. Exposed portions of trees must be protected from injury
since even "superficial" wounds provide avenues for attack by
insects and disease.
Cuts for roads and utilities and the installation of under-drains
will lower the location of the groundwater table. If the lowering
is severe, mature trees may be stressed to obtain sufficient
water during certain seasons of the year. This changed condition
often results in tree death. If these situations are recognized at
an early date, alternative measures may be elected that would be
211
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more desirable than the removal of dead trees after construction
is complete. A program to artificially sustain these trees may be
elected; or, it may be decided that tree removal early in the con-
struction operation is a better alternative than tree removal at
some time after construction is complete.
In the case where work must be performed under a particularly
valuable specimen, tunneling rather than trenching may be elected
in an effort to destroy as little of the root zone as possible. This
is, admittedly, expensive; but what is the cost of replacement for
a healthy mature specimen?
Filling over tree root zones should be avoided. Trees must breathe
and they respire through roots that occupy the zone of aeration in
the soil. Filling even a few inches moves the zone of aeration away
from the root zone and may cause the tree to die. If filling around
trees is required, they may be protected by the construction of dry
wells or other devices that will bring air through the fill to the root
system. Filling will often bring a tree's root system into the zone
of saturation in the soil and the tree will drown.
When selecting trees for preservation, several criteria must be
considered. In the case of wooded home lots, where lot size will
accommodate some flexibility in structure location, it may be
desirable to select the tree(s) that are to be saved and then site
the building. This approach will create minimal environmental
stress for those trees that are to be saved. Certain species are
more desirable than others. Tree health, condition, and confir-
mation must also be considered and may take precedence over
selection on a specific basis alone. Younger trees are often more
adaptable to modification of the environment than are mature
specimens. For this reason it may be desirable to remove a
mature tree and retain several young healthy trees that will more
easily adjust to changed environmental conditions.
Removal of some trees will expose the survivors to greater wind
velocities. This factor, coupled with some root damage, may
cause tree fall during wind storms. Selective tree removal in
favor of a single tall specimen may create a lightening hazard.
Intensive gardening is not compatible with root zone preservation
and should be considered with all of the other factors when evaluating
woodlands for conversion to the parkland environment associated
with "wooded" home lot construction.
Unfortunately, there are no simple or general answers and solutions
to the potential problems associated with tree preservations. Much
research is required in the area of urban forestry. Until such time
when answers to these, and other problems, are generally available,
evaluations will have to be conducted on a site-by-site basis. For-
tunately, professional guidance is available and should be utilized in
an effort to recognize potential problems early in the planning of any
development.
212
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FIGURE D-16. Incorrect fencing for tree protection
FIGURE D-17. Correct fencing for tree protection
213
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FIGURE D-18. Correct fencing for tree protection
FIGURE D-19.
Tree protection - selective stockpiling of soil
from basement excavation
214
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Isometric
Section
FIGURE D-20. Tree protection - tile and gravel will allow
air circulation to root zone under a fill
215
-------
Section
Plan
Section
Plan
Tunnel beneath root systems. Drawings on left show
trenching that would probably kill the tree. Drawings
at right show how tunneling under tree will preserve
many of the important feeder roots.
FIGURE D-21. Tree protection - tunnelling
216
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NOTES
217
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VEGETATIVE FILTER STRIP
Technical Information
DEFINITION:
A Vegetative Filter Strip is an area of vegetative cover through
which stormwater must flow before it enters streams, storm
sewers, conduits, etc. As the water containing suspended solids
flows through the filter strip, some of the sediment is removed
by "filtering" and by gravity sedimentation as the flow velocity is
reduced.
DESCRIPTION:
Almost any stand of vegetative cover will remove some sediment
from water flowing through it. These filter strips can be naturally
occurring or man-made and the type of vegetation utilized can be
very broad. Best performance is associated with tall, dense
stands of turf forming grasses.
NOTES:
The most common, naturally occurring filter strips are those
vegetation stands associated with floodplains or found adjacent
to natural swales and watercourses. They are also typified by
areas across flow routes that remain undisturbed through rough
grading operations. Preservation of these areas is all that is
generally required for them to function as filter strips. If these
filter strips are expected to perform for several months or more,
a light top dressing of fertilizer is recommended to improve the
stand.
Vegetative filter strips are being utilized during the course of
construction operations. As storm drainage systems are completed
it is possible to use sod filter strips at storm drain inlets that are
not curbline structures. In these cases it is very important that
the root zone development of the sod develop as rapidly as possible
in order that it will not be destroyed by water flowing into the
sewer. It is mandatory that a good "sod bed" be prepared in an
effort to establish the bond between sod and soil as quickly as
possible. Preparation of the "sod bed" should proceed as if
seeding were to be used. The soil is loosened to a depth of
3-4 inches; all rocks and stones are removed; fertilizer, lime,
etc., are added and worked in; and the bed is smoothed. The sod
is then placed, rolled, and irrigated daily until the bond between
turf and soil is firmly established (2-3 weeks).
218
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It.-:
FIGURE D-22. Sod filter strip on stockpile for winter protection
FIGURE D-23.
Sod filter strip and straw bales on stockpile
for winter protection
219
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FIGURE D-24. Sod filter strip at storm drain inlet
FIGURE D-25. Sediment deposition at sod filter strip
220
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NOTES
221
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WOODLAND CLEARING AND EXCAVATION
Technical Information
DEFINITION:
Woodland Clearing and Excavation involves the clearing of trees
from construction sites and the excavation that is associated with
construction in wooded areas.
DESCRIPTION:
The results of current applied research in these categories
suggests that they can be conducted in a manner that is more
compatible with an overall conservation scheme. From a sedi-
ment and erosion control standpoint, the removal of any vegeta-
tion is deleterious. Where trees must be removed, effort should
be expended to complete the work in a manner that is consistent
with sediment and erosion control programs. This includes tree
and stump removal in ways that will not create additional prob-
lems. It includes the use or reuse of the wood products generated
during the clearing operation. It also includes the protection of
trees that are selected to remain in the future from damage during
excavation work.
NOTES:
Disposition of trees cleared from construction operations has
historically been accomplished by burning or by removal to land-
fill sites. Stumps are removed by dozer or blasting. These
methods are expedient; they are also inconsistent with current
environmental concern.
Wood generated from clearing operations should be utilized.
Timber should be salvaged. If the wood is not timber quality, it
should be prepared for public or private fireplace use. Material
not used for timber or fireplaces should be processed through
woodchippers and the product used in sediment and erosion con-
trol programs on-site or in adjacent areas (See Appendix C for
woodchipuse). Although woodchippers in common use today are
usually limited to limbs and branches of 4 inches, larger machines
are being built and some will be capable of handling all but the
largest branches and trunks. Stumps should be removed by "stump
cutter" (Appendix C) rather than by dozing or blasting.
Care must be exercised during clearing operations that trees
selected for preservation are not damaged (Appendix D). Damage
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can be imparted by falling trees, equipment travel, and "barking"
by heavy equipment.
Construction excavation in wooded areas can be carried out in a
manner that will stress remaining trees as little as possible.
Spoil should be selectively piled away from root zones. Where it
is impossible to pile spoil elsewhere, it should remain on the root
zone only a very short time. If it is to be removed from the site,
it should be done promptly. If it is to be utilized for landscaping,
it should be done promptly. It should not remain piled on the
root zone.
Equipment operators digging foundations and basements should
not clean their equipment by "slamming" it against the trunks of
trees.
If the excavation is wet, professional guidance should be secured
when a dewatering scheme is selected. Trenching in the woods is
not compatible with tree preservation and should be avoided when-
ever possible. This is especially true when this type of remedial
action is of an "expedient1 nature and will be carried out beyond
the right-of-way or outside the designated construction area.
Another fact to be integrated into the planning of woodland clearing
is that remaining trees will be stressed the least if excavation
work is conducted "when the leaves are down. " This option is
available only in temperate climates where deciduous trees grow.
It is, however, worthy of consideration in areas where selected
trees will be preserved.
223
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FIGURE D-26. Trees marked for preservation
'. , M • - .
FIGURE D-27. Taking down a tree after home construction. Tree
is too close to house and should have been removed
when lot was cleared since its root system has been
severely damaged by excavation for a basement.
224
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FIGURE D-28. Tree with visible damage. Existing damage should
be assessed when selecting trees for removal or
preservation.
FIGURE D-29. Section of tree trunk (Figure D-28) after removal.
Note damage caused by carpenter ants.
225
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FIGURE D-30. Equipment travel in this area has seriously damaged
root systems of trees marked for preservation
FIGURE D-31. Access route for material delivery to basement
has cut roots of beech tree on left
226
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FIGURE D-32. Woodchips being returned to forest
FIGURE D-33. Woodchipper being fed
227
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FIGURE D-34. Drainage ditch for "convenience" of utility
construction has been cut on private property
well outside right-of-way
NOTES:
228
f-U.S. GOVERNMENT PRINTING OFFICE: I97J S14-14O/19 1-3
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/. !.,;?,! No.
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GUIDELINES FOR EROSION AND SEDIMENT CONTROL
PLANNING AND IMPLEMENTATION
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Mills, Thomas R.
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WATiR Rl snUKCT'.- ••<••: I :-:r:i'IC INI I
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WAI.HI NLjTON D C 20^40
Hittman Associates, Inc.
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