United States
          Environmental Protection
          Agency
           Office Of
           Research and Development
           Washington, DC 20460
EPA/625/3-76/006a
October 1976
S-EPA
Erosion and
Sediment Control

Surface Mining in the
Eastern U.S.

Volume 1: Planning

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EPA-625/3-76-006
                      EROSION AND SEDIMENT  CONTROL
                                            Surface  Mining in
                                             the  Eastern U.S.
                                                       Planning
 ENVIRONMENTAL PROTECTION AGENCY* Technology Transfer
                          October 1976
                                              Printed on Recycled Paper

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                  ACKNOWLEDGMENT
   This seminar publication contains materials prepared for the U.S.
Environmental  Protection Agency,  Resource  Extraction  and
Handling Division, Industrial Environmental  Research Laboratory,
Cincinnati, Ohio, and Technology Transfer Program.
   The information in this publication was prepared by Thomas R. Mills
and Michael L. Clar, representing Hittman Associates, Columbia, Md-,
under Contract No.  68-03-2213.  The following people also provided
technical contributions to the manual:  P. Brown, P. Hartman, V.
Kathuria, and G. Sitek.          ',
   Mr. Elmore C. Grim, of the Extraction Technology Branch, Resource
Extraction Handling Division, was the project officer.
   Sincere appreciation is extended to Mr. Marshall Augustine for his
guidance as a consultant on the project.
   The assistance and cooperation  of numerous Federal and State
agencies in the preparation of the manual are hereby acknowledged.
Special thanks are extended to the following people and the agencies
they represent for their contributions to the manual: Dr. L. Donald
Meyer, U.S. Department of Agriculture (USDA) Sedimentation Labo-
ratory; Mr. Graham T. Munkittrick, Maryland USDA Soil Conserva-
tion Service (SCS); Mr. W. Curtis and his staff, U.S. Forest Service;
Mr. Benjamin C. Greene, West Virginia  Division of Reclamation;
Mr. E. E. Filer, Illinois Division of Surface Mine Reclamation; Mr. R.
McNabb, Indiana Division of Reclamation; Mr. Ken Ratcliff, Kentucky
Division of Reclamation; Mr. Chase Deloney, Tennessee Division of
Surface Mining; Mr. Ronald Hardy, Kansas Geological Survey;  Mr.
Ward Padgett, Oklahoma Department  of Mines; Mr.  Robert Neun-
schwanzer, Missouri Land Reclamation Commission; Mr. Ken Faulk,
Ohio  Division of Reclamation; Mr.  Bill Roller, Virginia Division of
Mined Land Reclamation; Mr.  ;Ken Weaver,  Maryland  Geological
Survey;  Mr. William Guckert, Pennsylvania Division of Surface Mine
Reclamation;  Mr. Marvin Ross,  Iowa Mines and Minerals Division;
.Mr. Ashley Thornburg, SCS Midwest Technical Service Center;  Mr.
William Plass, U.S.  Forest  Products  Marketing  Laboratory;  Mr.
Edward Helenic, Ace Drilling Company; Mr. Walter Armiger, USDA
Agricultural Research Service; Mr.  George Holmberg, SCS Division
of Surf ace Mining; Mr. Curtis Sharp, SCS Northeast Technical Service
Center; Mr. Kenes Boiling, Interstate Mining Compact; Mr. Michael
D. Ellis, Amax Coal  Co.; and the many operators, inspectors,  and
agencies' personnel too numerous to mention.
                             NOTICE

  The mention of trade names or commercial products in this publication is for
illustration purposes, and does not constitute endorsement or recommendation for use
by the U.S. Environmental Protection Agency.

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                                          I
                                      CONTENTS

                                       Volume I
                                          !                                          Page
 List of Figures	. .... j... .         .                                •
 List of Tables	".''.':".'.]'.'.'.'.'.['.'.'. ...................  	 v

 Section 1.  Introduction	].....	                        1
      Purpose and Scope. . .	..:... .j........ .". ......... ..'.'.'.'.'.r         	1
      Use of the Manual . .	j	'...".	       . . .	l

 Section II. The Problem	i. . . ..';	      -;. .... ..";..               3
      Sediment as a Pollutant	I.	                	3
      Sources of Sediment Pollution	 j. .............                 	5
      Sources of Sediment from Surface Mining		   	6
      References	j	              	'•, -,

 Section III. Control Rationale	'.	:'.....,        ;  • •                    13
     Overview	i................               	13
     Erosion and Sediment Control Principles.!	•	  . . '. '. '. '. '. '. '. '. '.'.'.'. '. '. ' 13
 Section IV. Erosion Control	'..;.'	        !.....                23
     Types of Erosion	 . .    _       .  "  ' ' ' ' '	23
     Factors Influencing Erosion	..........:	.....!.                   25
     Runoff Control	 .. .1	        ....                	29
     Soil Stabilization	;	!........	'.....	                    38
     Vegetative Establishment. .  .	.1. .. ^ ..;;............   '.'.I'.'.'.'.'.'.'.'.'.	45
     Maintenance	!	   _     	56
     References  .	 . .'	               	5«

 Section V.  Sediment Control	,	j		                  59
     Sediment Transport and Deposition. .... I	'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.	59
     Factors Influencing Sedimentation .....'.		59
     Sediment Containment Strategy ... ....'..............   ............   '  '	5g
     Types of Control	i ...... .1 ..............   .... '.''.''.   	61
     Maintenance	1.	                  	go
     PostminingConsiderations	   ...[.......... . . . . ..'     .....!	71
     References . .	.[........'.,. . '. ...              	72
 Section VI. Control Plan	 . j	;	_ ,                        73
     Legal and Technical Requirements	:	              '  	73
     Evaluation of Site Information. ......;.].	                             	70
     Control Strategy .. . .	 I	'...'' '  ','"''	
     Evaluation of Preliminary Sketch Plan .. j..'....	..........!!  	83
     Revision and Finalization of the Plan. . .. j	      .       [[	g3
     References	\. .	                  	04

 Section VII. Implementation	'. j	                g5
     Inspection Responsibilities	j	   ' '  ' 85
     Onsite Plan Review	j	                 ' ' 89
     Onsite Inspection	j	                 gg
     Guides for Inspection and Evaluation of Erosion and Sediment Control Measures	 ! . 89
Section VIII.  Glossary	 j	                gg
                                          i

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                                   LIST OF FIGURES
                                             ;                                       ' Page
1-1. Geographic area covered by manual	2

II-l. Sediment as a pollutant	,	•	3
II-2. Sediment deposited in a natural stream.	4
II-3. Annual costs of sediment pollution.	•	5
II-4. Clearing a steep slope ahead of a contour-mining operation	6
II-5. Poorly drained and stabilized haul road.	;	• •	8
II-6. Erosion at unstabilized culvert outlet	P	•	8
II-7. Fugitive dust from haul road	,	9
II-8. Newly graded, long, steep slope, highly vulnerable to erosion	11

III-l. Reclaimed mined land	14
III-2. Haulback contour mining in Appalachia, used to minimize site disturbance	.15
111*3. Mined land returned to approximate original contour and used for farming	15
III-4. Staged reclamation to minimize area of exposure	,	16
III-5. Well-stabilized outslope on head-of-hollow fill	18
III-6. Closeup of mine spoil stabilized with vegetation to reduce soil loss.	18
III-7. Reverse benches or terraces used to control runoff on long slopes	19
III-8. Vegetative buffer	20
III-9. Sediment basin used to trap sediment coming from mine site	20
III-10. Inspection of riser pipe on sediment basin.	21

IV-1. Soil erosion process	|	23
IV-2. Severe sheet erosion from raindrop impact and splash	24
IV-3. Rill erosion	,	• • 24
IV-4. Severe gully erosion on mine spoil	•-.	25
IV-5. Stream channel erosion	26
IV-6. Surface runoff	•	•	26
IV-7. Soil particles are bound together by root system	27
IV-8. Steep slope and fine-textured, structureless nature of a loessial soil contributed to
   severe erosion at this mine in the Midwest	29
IV-9. Grading and shaping of soil surface	30
IV-10. Properly roughened (along the contour) fill slope	31
IV-11. Mine spoil roughened by tracking	31
IV-12. Slope reduction measures	 :	33
IV-13. Diversion structures (terraces) on long, steep slopes	34
IV-14. Interception and diversion measures	34
IV-15. Newly constructed diversion	35
IV-16. Stone riprap waterway lining used to dissipate flow and protect channel	 36
IV-17. Concrete half-round pipe downdrain	,	37
IV-18. Half-round bituminous fiber pipe used for temporary handling of concentrated flow.. . . . . 37
IV-19. Spoil and drainageway well stabilized with grasses and legumes..	38
IV-20. Outslope stabilized with short-term annual grasses	39
IV-21. Newly seeded and mulched area adjoining'ditch lined with stone riprap	40
IV-22. Straw mulch			•	41
IV-23. Chemical stabilizer being applied over straw mulch	41
IV-24. Access road with aggregate surface.	42
IV-25. Stone gabion structure	i	43
IV-26. Stone riprap protecting bends in stream.		46
IV-27. Riprap check dam (grade control structure^ placed in a drainageway	46
IV-28. Well-prepared seedbed		• • •	 52
IV-29. pH scale	53
                                            IV

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                                           i                                            Page
  IV-30. Hydroseeding a graded and properly roughened mined area	56
  IV-31. Comparison of straw-mulching rates arid surface coverage	57
  V-l. Trapping sediment on the bench near its source	60
  V-2. Perimeter sediment basin at a surface co^l mine	60
  V-3. Slope roughening and flattening to trap spdiment near its source..	61
  V-4. Natural vegetative buffer below a haul road	62
  V-5. Vegetative buffer strip below a spoil banli trapping sediment	62
  V-6. Excavated trap on a construction site.. . [	63
  V-7. Stone check dam trapping sediment. . . . [	...'.'. ."...'	..63
  V-8. Sandbag barrier	[	   64
  V-9. Straw bale barrier	 . j	64
  V-10. Log-and-pole structure	I	 .'.',..:. ."		65
  V-ll. Sediment basin	,. j	         .66
  V-12. Sediment basin functioning during a storm	66
  V-13. Basin inspection.	 .-.-..;	.69
  V-14. Well-built and -maintained basin. ..-.•-.-.-1 .;.'.'	 ,		70
  V-15. Backhoe loading sediment into a truck fr transport to a disposal area.	71
  V-16. Diked sediment disposal area on relatively flat ground.	72

  VI-1. Gathering topsoil samples	 K	78
  VI-2. Core drilling to gather information on overburden and coal	 .  78
  VI-3. Area mining in the Midwest	.j	79
  Vl-4. Haulback contour mining in AppalachiaJ	80
  VI-5. Contour furrows and diversion swale controlling erosion and protecting lower lying
    waterway	••	81
  VI-6. Diversion ditch along perimeter of disturbed area		 82
  VI-7. Sediment basin badly in need of cleaningl	;	 82
  VII-1. Operator-inspector team	'r	',',	85
  VII-2. Protect streams by providing stable cro'ssings.	87
  VII-3. Water sampling below surface mine site!.	 .	88
                                      LIST OF TABLES
 • II-l. —Representative rates of erosion from various land uses	......	5
 II.-2.—Comparative rates of erosion	 . . .1.	      7
                                           I
 I V-l.—Size limits of soil separates..	 .	28
 IV-2. —Basic soil textural class names		,	28
, IV-3. —Maximum permissible velocities in channels lined with uniform stands of various
   grass covers, well maintained	j	 . ... 45
 I V-4.—Characteristics of commonly used grasses for revegetation purposes	47
 IV-5. —Characteristics of commonly used legumes for revegetation purposes	50
 IV-6.—Commonly used trees and shrubs.. .. . .j.	.51
 IV-7. —Agricultural lime needed to increase surface mine spoil pH to specified level	.54
 V-l.—Results of pond sampling during rainfalljconditions	 67
 VI-1. —Effluent standard for the surface mining industry	 . .	74
 VI-2. —Information checklist for an erosion and sediment control plan..	75
 VI-3. —Published information aids	i	76

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                                         Section  I

                                    INTRObuCTION
   The development of technology for the control
 of erosion and sedimentation has been underway
 for many years. Originally, the research efforts
 focused primarily on agriculture. Subsequently,
 the increasing magnitude  of erosion and sedi-
 mentation problems resulting from  an acceler-
 ated  rate of urban expansion was recognized,
 and  control technology  was  developed  and
 tailored to those conditions. Recently, increasing
 public concern, combined with the greater reli-
 ance being placed on coal as America strives for
 energy independence, have resulted in State and
 Federal laws making sediment controls manda-
 tory for surface coal mining.
 mining operation; (2) avoiding offsite damage
 that often leads to legal action to recover dam-
 age.
   The control information presented is directed
 primarily toward preventing excessive soil loss
 and resulting damage associated with coal sur-
 face mining operations in the eastern portion of
 the United States, specifically the Appalachian,
 eastern interior, and  western  interior coal re-
 gions (fig. 1-1).  However, much of the material
 and certainly all of the basic erosion and sedi-
 ment  control philosophy are applicable to all
 categories of surface mining in  all regions of the
 country.
          PURPOSE AND SCOPE

   The primary purpose of this manual is to pro-
vide guidelines that will help those engaged in
surface coal mining prevent  the  uncontrolled
movement of soil  and the offsite damage it
causes. The manual has been written for use by
technicians, professionals, and laymen to:

•  Provide them with an understanding of the
   mechanics of soil erosion and sedimentation
   and the physical  factors which determine the
   nature and extent of these processes
•  Provide them with a thorough understanding
   of erosion and sediment control rationale
•  Familiarize them with basic  control proce-
   dures, practices, and products
•  Provide them with basic  information on the
   design, construction, and utilization of con-
   trol structures

   This  document is not a design  manual, but
rather a manual that presents the "how" and
"why" of  erosion and sediment control technol-
ogy and provides general guidelines for formu-
lating and implementing a  control plan for a
surface mining operation.
   In  addition to its primary objectives,  it is
expected that the manual will produce several
secondary benefits.  These include:  (1)  savings
in the cost of development and maintenance
activities, through  proper preplanning of the
           USE OF THE MANUAL

   The manual consists of two volumes. The six
 sections in volume I cover all the basic concepts
 of erosion and sediment control. The text has
 been designed to provide the technician and the
 layman with a thorough explanation of the need
 for control,  basic control principles, available
 technology  for  erosion and sediment control,
 and procedures for preparing and implementing
 a control plan.
   Section II discusses -and defines the nature
 and extent of the sediment problem and identi-
 fies the major sources of sediment generated by
 surface mining operations.
   Section III presents the control rationale and
 discusses the basic philosophy underlying  ero-
 sion and sediment control. The foundations of
 this control philosophy are made up of five  ero-
 sion and sediment control principles that form a
 recurring theme throughout the manual.
   Sections IV and V address erosion and sedi-
 ment control 'technology. The  various  control
 practices are grouped in a functional order.  The
 control methodology is discussed in groups hav-
 ing a specific purpose rather than individually.
 For example, erosion control practices have been
 grouped  into the two  basic functions: runoff
 control and soil stabilization. The intent of these
 two sections is to provide the  reader with an
insight into  causative factors and basic control
                                             II

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strategy.  Emphasis is  placed on providing a
thorough  understanding of  the  "how"  and
"why" of major categories of control rather than
individual practices. References frequently are
made to specific practices  where  appropriate.
Many of these practices are discussed in greater
detail in volume II.
  The preparation of a control plan is covered
in section VI. A step-by-step procedure for the
preparation of a  control plan is discussed; In
  presenting the procedure, discussions  of legal
  and technical requirements, information require-
  ments, control strategy development,  prelimi-
  nary sketch plan evaluation, and final control
  plan preparation are provided.
    Section VII deals with implementation of the
  control  plan. Inspection  requirements  and
  responsibilities are discussed, and guides for
  inspection and evaluation of erosion and sedi-
  ment control measures are provided.       .  ,
             bituminous
anthracite
                          Figure 1-1. Geographic area covered by manual.
                                              2

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                                       Section II

                                    THE PROBLEM
       SEDIMENT AS A POLLUTANT

  Surface mining operations, like all other large-
scale, earth-moving operations, have the poten-
tial to generate large volumes of sediment. As
long as the sediment generated is contained on
the mining site, it does not present a problem.
However,  if it washes into neighboring water-
courses, it becomes a resource-out-of-place and
a pollutant by definition, as illustrated in figure
II-l. Sediment is widely regarded as the greatest
source of water pollution in the United States.
The following is a list of some of its detrimental
effects:1
Occupies water storage in reservoirs
Fills lakes and ponds
Clogs stream channels
Settles on productive land
Destroys aquatic habitat
Creates turbidity that detracts from recrea-
tional use of water and  reduces  photosyn-
thetic activity
Degrades water for consumptive uses
Increases water treatment costs
Damages water distribution systems
Acts as a carrier of other pollutants (plant nu-
trients, insecticides, herbicides, heavy metals)
Acts as a carrier of bacteria and viruses
Sediment
contained
on site
                    No
                    problem
               =  POLLUTION
                              Figure 11-1. Sedirjient as a pollutant.

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   Sediment can be transported long distances
by high flows. But, being heavier than water, it
is deposited ultimately in stream channels (fig.
II-2—notice sediment buildup in lower left cor-
ner), ponds, reservoirs, and on floodplain lands.
These deposits are an obstruction to navigation,
water supply storage, flood control, and power
generation in downstream areas. Sediment
deposition also destroys the habitat of many
forms of aquatic life and decreases the value of
floodplain  areas for recreational and agricul-
tural uses.              ",,
   Sediment is displaced soil.  However,  most
soils in the Eastern United States do not look at
all like the deposits of sand and gravel in stream
and river beds. This is because the top soil
layers are composed of much smaller particles
that can be transported over greater distances
and remain suspended in water for longer periods
of time. The suspension of these particles causes
turbidity that degrades the usefulness of water
 for many purposes and increases the costs of
 water treatment.  Turbidity also has substan-
 tial biological effects in decreasing the amount
 of  sunlight  that  reaches  aquatic  plants and
 in  decreasing the oxygen  that is available to
 fish.
 •  That small particles of  suspended sediment
 muddy the water is only the tip of the iceberg.
 These small particles are also capable of carrying
 some of the microscopic elements in soils along
 with thein. Suspended sediment particles trans-
port  nutrients, fertilizers, pesticides,  heavy
 metals, and  disease organisms. This  aspect of
 sediment pollution may have severe effects on
 water quality resulting in public health hazards
 and .irreversible changes in aquatic  biological
 systems.
   Sediment pollution is costly. The annual dam-
 age from sediment in streams was estimated to
 be  $262 million in 1966.2 The breakdown of this
 cost is shown in figure II-3.
 \J-!
                              .-**•
                        Figure 11-2. Sediment deposited in a natural stream

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 $83 million —
 dredging sediment from
 inland navigation
 channels and
 harbors
 $14 million —
 removal of excess
 turbidity from
 public water
 supplies
 $31 million —
 other damages
 including sediment
,. removal, cleaning,
'•and added maintenance
                                $50 million —
                                deposition on
                                floodplains
                                $50 million —
                                storage space
                                destroyed in
                                reservoirs
                                $34 million —
                                removal of
                                sediments from
                                drainage and
                                irrigation canals
                             Figure II-3. Annual costs of sediment pollution.
    SOURCES'OF SEDIMENT POLLUTION
    Land-disturbing activities  associated with
 mining, construction, agriculture, and silvii
 culture are the major sources of sediment. Farm-j
 ing, particularly crop farming, is the chief source
 of sediment in the United States. Fifty percent]
 or more of the sediment deposited in streams
 and lakes as a result of man's activities is attrib-'
uted to agricultural sources. Construction and
surface mining activities, though not as wide-
spread, can yield large quantities of sediment to
nearby waterways,  causing  severe adverse
effects. Table  II-l lists representative rates of
erosion from various types of land uses. It can
be seen that on the basis of a uniform area of
disturbance, active surface mining operations
and construction operations have the highest
rates of erosion.
                      Table 11-1 .—Representative rates of erosion from various land uses
Land use
Forest 	
Grassland 	
Abandoned surface mines ....
Cropland 	
Harvested forest 	 	
Active surface mines 	
Construction 	

Metric tons per km2
per yeajr
8 5
85 6
850.0
1 700 6
42500
17 0000
1 7 000 6

Tons per mi2
per year
24
740
2,400
4 800
12 000
48 000
48 000

Relative to forest = 1
1
m
100
onn
Ron
2nnn
2nnn

    Source: Methods for Identifying and Evaluating the Nature and Extent of Nonpoint Sources of Pollutants, EPA-4030/9-73-014,
  Washington, D.C., U.S. Environmental Protective Agency, Oct.i1973.
                                               I  5

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     SOURCES OF SEDIMENT FROM
            SURFACE MINING

   The major sources of sediment in surface
mining operations are areas being cleared,
grubbed, and scalped; roadways; spoil piles and
areas of active mining; and areas being re-
claimed. Some common causes of sediment yield
from these sources are discussed below.

Areas Being Cleared, Grubbed,
and Scalped
   Factors contributing to  soil loss and, ulti-
mately, water contamination from clearing and
grubbing operations (fig. 11-4) are:
• Failure to install perimeter control measures
  prior to the start of clearing and grubbing
• Exposure of soils on steep slopes
• Overclearing—clearing too far above the high-
  wall or below the outcrop line
• Clearing and grubbing too far ahead of the
  pit, exposing the soil for an excessive length
  of time
• Improper placement and/or protection of sal-
  vaged and stockpiled topsoiling material
• Creation during clearing and grubbing opera-
  tions of a soil surface that impedes infiltration
  and/or concentrates surface runoff (for exam-
  ple, leaving ripper marks or dozer cleat marks
  that run up and down the slope rather than
  along the contour)

r-—'^
•yml	i	   	H itai	HjiBBlI	m.
                                                   '
    -I"  -  ' i.
               Figure 11-4. Clearing a steep slope ahead of a contour-mining operation.
                                           6

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Roadways (Haul and Access Roads)

  Roadways are a major source of sediment
from surface mining operations. This source is
often given inadequate consideration in the for-
mulation of  an erosion  and sediment control j
plan, yet roadways are often the major source i
of sediment,  as well as a conduit for sediment
washing down from other areas of the mine into
the natural drainage system. Table  II-2 pro-
vides an interesting comparison between the
rates of erosion for different areas,  including
haul roads, within a monitored watershed  in
Appalachia.
      Table 11-2.—Comparative rates of erosion
Area
Unmined watershed .
Mined watershed . . .
Spoil bank 	
Haul road 	

Within the mining
Yield
(ton/mi2)
28
1,930
27,000
57,600

area itself, road1
Factor
1
69
968
2,065

ways gen-
erally remain a source of sediment throughout
the life of the mine, whereas adjoining spoil areas j
can be graded and stabilized with vegetation in j
a  relatively  short period of time.   Roadways!
constructed outside the actual mine site to gainj
access to the operation are also a major source!
of sediment pollution over the life of the mine,j
and often beyond, if proper control measures
are not  employed. Long access roads signifi-;
cantly disrupt  the  natural drainage  system, j
Roadways serve to intercept, concentrate, and
divert surface runoff. This results in severe soil
loss from roadway surfaces, ditches, cut slopes,
outslopes, and safety berms. Additionally, thej
overall increase in the  rate of runoff resulting:
from the construction of a relatively imperme-;
able roadway surface, the clearing and steepen-:
ing of slopes, and the interception and concen-j
tration of sheet runoff from upland areas will,
accelerate erosion within natural drainageways.i
Accelerated  onsite and offsite erosion will con-j
tinue to  be a source of water contamination well
beyond the life of the mine if, when the mine is;
abandoned, measures are not taken to stabilize]
exposed surfaces permanently with vegetation
and to minimize disruption of the natural drain-j
age system.                                  j
   Factors contributing to  soil loss from  road-j
ways and offsite areas affected by the roadways;
are outlined below:                           j
Poor location of the roadway,  resulting in
one or more of the following adverse condi-
tions:
— The presence of excessively long or steep
  grades contributes to erosion by concen-
  trating runoff and increasing its flow veloc-
  ity,  .                   .
— Disturbance, either by filling or excavation,
  of unstable slopes or areas having a high
  ground water  table  may, result in land-
  slides, muddy roadbed conditions, and re-
  vegetation problems.
— Failure to preserve vegetated buffer (filter)
  areas  along waterways  allows the move-
  ment of sediment from  the roadway into
  the waterway.
—Creation  of  unnecessary, or  unsuitable,
  stream crossings,  contributes to erosion of
  the banks and bed of the affected water-
  ways.

Improper construction of the roadbed:

— Rutting and  saturation of  the roadway
  results from  failure  to  provide  adequate
  bearing capacity and/or  subsurface or sur-
  face drainage (fig. II-5). These conditions
  are conducive to  gully  erosion and land-
  slides.
— Failure to provide a surfacing  material,
  such as clinker or crushed stone, or  good
  compaction seal on suitable material,  ex-
  poses the soil to the erosive action of water,
  wind, and traffic damage.

Improper layout and construction of drainage
structures:

— Failure properly to size, shape, and stabi-
  lize ditches: Improper sizing and shaping
  can result in increased flow velocities,
  which increase soil loss and the ability of
  the runoff to carry sediment into adjoining
  waterways/Lack of adequate stabilization
  with structures and/or  vegetation makes
  the channel more susceptible to erosion and
  also provides for  increased flow velocity.
— Improper handling and disposal of concen-
  trated runoff: Failure properly to install
  culverts, or other conduits, to carry concen-
  trated flow beneath the roadway can result
  in gully erosion within the ditch, flooding,
  and subsequent saturation of the roadway.
  In some  instances' (especially where side-
  hill fills are present), landslides may result.
  Disposal  of concentrated flow, such as the
  runoff discharged from culverts, can cause
  severe gully and stream-channel erosion if
  stabilization and energy dissipation meas-
  ures are not used (fig. II-6).

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   ' '   *'  *  '  ''  '  '
                              •   -.        '  -      l
     -  ii-     -


m&4
if"? >::;«i . I.-M
             Figure 11-5. Poorly drained and stabilized haul road.
              Figure 11-6. Erosion at unstabilized culvert outlet.
                              8 '

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Poor maintenance practices:

— Failure to control dust during dry periods
  (fig.  II-7):  Dust  particles deposited  in
  ditches, on the roadbed, and uphill from the
  roadway are washed readily into adjoining
  drainageways during rainfall events.
— Pushing soil into the ditch when perform-
,  ing maintenance grading.

Inadequate stabilization of cut and fill slopes:

,—Construction of excessively steep slopes:
  Slopes  steeper than 2:1 or 50 percent are
  difficult, if not impossible, to stabilize ade-
  quately with vegetation. Excessively steep
  slopes also increase the likelihood of land-
  slides.
— Failure to establish vegetation  properly:
  Improper selection and application of plant
  materials,  soil supplements, and mulches
  along with negligent maintenance practices
  result  in only partial protection of steep
  ; slopes.                        ---.••

Failure to protect safety berms:
— Shaping the roadbed to allow runoff to con-
  centrate and flow along the berm: Berms
  located along crowned roadways and  con-
  structed of loose overburden that is devoid
  of vegetative cover are particularly vulner-
  able to erosion.
— Absence of stabilized outlets, or improper
  placement  of outlets, along the,berm: Fail-
  ure to  provide stabilized breaks at periodic
  intervals along the berm will contribute to
  an ircrease in flow velocity and erosion.
                          Figure 11-7.  Fugitive dust from haul road.

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 Unreclaimed Spoil Piles and
 Areas of Active Mining

   Surface mining disrupts the natural drainage
 system. If the disruption prevents runoff from
 leaving the disturbed site, the likelihood of sedi-
 ment being carried into adjoining waterways is
 greatly reduced. However, should surface drain-
 age from the disturbed area have uninterrupted
 access to the adjoining drainage system, then
 serious downstream sedimentation problems are
 a distinct possibility. The first condition is likely
 to be encountered over much of the mine site
 where area strip mining or other forms of area
 mining are performed.  The latter condition  is
 more prevalent  with contour strip mines, par-
 ticularly where a portion of the spoil is placed on
 the outslope.
   At area strip  mines, the spoil cast below the
 outcrop line usually has the  greatest potential
 for causing  offsite  sediment damage. Water
 pumped from the pit during rainfall events  is
 another significant source of sediment and other
 contaminants.
   At contour strip mines similar  conditions
 exist,  but  the overall  potential for sediment
 damage is generally much greater. Several fac-
 tors contribute to the magnitude of the problem.
The most significant one is that contour mines
 have a narrow, linear geometry and, therefore,
 more spoil area  drains directly into  the offsite
 drainage system.  Also,  the  bench area being
 actively mined,  unlike the pit area  of an area
 strip mine, often drains directly into the offsite
 drainage system. Another factor, one of extreme
 significance,  is that the receiving waterway  is
 generally closer  to the source of sediment and
 separated from  the source by relatively steep
 terrain. Additionally,  the  contour strip mine
 site  receives  more potentially  erosive runoff
 from undisturbed areas at higher elevations due
 to the shallow soils and the  linear exposure  of
 the mined area to drainage areas above it.
   In  recent years, mountain-top-removal min-
 ing has been, in some areas, an alternative  to
 contour strip mining. Due to the variability  in
 mountain-top-removal operations,  it  is difficult
 to generalize as  to the overall potential for off-
 site  sediment damage  from such operations.
 However, considering the areal nature of these
operations  and  the overall reduction  in relief
 that is achieved, the potential for offsite sedi-
ment damage is  likely to be less than for a con-
 tour strip mine disturbing an  equal area of land.
This is particularly true when surface drainage
is controlled internally (that is, within the mine
site). These advantages could be offset in some
instances by problems with  chemical and acid
pollution and landslides.
   From the standpoint of soil loss and sediment
damage,  the most critical areas at a mountain-
top-removal site are the spoil slopes around the
perimeter of the site, roadways exiting from the
mine, and valley or head-of-hollow fills. The fills
are especially critical in that they are placed in
drainageways  and,  consequently,  are  highly
susceptible to  piping  (subsurface removal of
soil), and landslides. Loss of soil from the face of
the fill slope due to  rainfall and runoff can be
another serious problem.

Areas Being Reclaimed

   While reclamation is  a  means of  achieving
overall environmental, economic (productivity),
and cultural (esthetic) benefits, certain reclama-
tion activities can be a major source of damag-
ing sediment if they are not performed properly.
   From  the standpoint of potential sediment
damage,  the most crucial stage in the reclama-
tion of spoil areas is from the start  of grading
operations to the stabilization of the spoil with
vegetation and structural measures  (fig. 11-8).
Except when the intention is to construct inter-
nal water impoundments, grading reestablishes
the premining drainage system. As a result, the
entire graded area and portions of the spoil piles
along the perimeter become a potential source of
offsite sediment damage. This condition is most
significant where forms of area mining are per-
formed—particularly at area strip mines.
   The configuration of the graded areas,  and
the measures taken in reestablishing drainage-
ways, also influence soil loss and offsite damage.
The construction of excessively long or steep
slopes, and the failure to stabilize structurally
the channels  of  reconstructed  drainageways,
will aggravate the problem.
   The measures taken to revegetate the graded
spoils will also have a major influence on soil
loss and  offsite damage. Improper tillage prac-
tices, such as tilling up and down a slope rather
than  along the contour, will greatly increase
soil loss. Even more significant  are the long-
term  vegetative  consequences  resulting  from
improper seedbed preparation, plant material
selection, and followup maintenance.

Receiving Waterways

   Waterways located immediately downstream
of surface mining operations are another poten-
tial source of sediment. These stream channels
are not within the limits of the mining operation
and are often not considered. Emphasis is gen-
erally placed on controlling erosion  and  sedi-
ment from the areas being mined. However, the
surface mining operations can produce substan-
                                              10

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                 Figure 11-8. .Newly graded, long, steep slope, highly vulnerable to erosion.
 tial modifications to the hydrologic equilibrium,
 especially if several operations  are  conducted
 concurrently in the same watershed. Permitting
 of surface mining operations is conducted on an
. individual basis. At present there are no limits
 on the number of operations and, therefore, the
 percentage of areal disturbance on a watershed
 basis.   .                                   I
   The two most significant hydrologic modi-
 fications that impact the receiving stream chan1-
 nels are increases in the rates and total volumfe
 of surface runoff.  Sudden changes in these
 two parameters of  the hydrologic  equilibrium
 coupled  with the  accompanying increase in
 sediment concentrations in the surface runoff
 adversely impact the  stability  of  the stream
 channels. An adverse  chain reaction of downi-
 cutting of the channel bottom and undercutting
and sloughing of the stream banks can be trig-
gered, which may continue to contribute sedi-
ment long after the surface mining operations
are complete.
                REFERENCES

   'A.  R.  Robinson, Sediment,  Our  Greatest
Pollutant,  American  Society  of Agricultural
Engineers, St. Joseph, Mich., Dec. 197Q.
   2J. B. Stall,  "Man's  Role in  Affecting  the
Sedimentation  of  Streams  and  Reservoirs,"
Proceedings of the 2nd Annual American Water
Resources  Conference,  American Water  Re-
sources  Association,  University of  Chicago,
pp. 79-85.
                                               11

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                                        Section IIS

                                CONTROL RATIONALE
                 OVERVIEW                 I
                                             !
   The overall goal  of this manual is to helpj
 achieve effective and reasonable  control over \
 erosion and sediment problems resulting fromi
 surface coal mining activities by using the best!
 practical  combination of available technology j
 and human resources.                         I
   Effective and reasonable control means that:
 every  effort should  be  made to achieve the j
 greatest  control without placing unreasonable
 demands on other activities at the mine. Accom-
 plishing this requires a clear understanding of
 all.elements of the mining operation and their
 interrelationships. It also means that environ-1
 mental control and production objectives must J
 be  integrated when  mining  operations are |
 planned.                                     j
   As with other major earth-disturbing  activi- j
 ties attributed to man, environmental damage j
 resulting  from surface mining operations must j
 be controlled. This does not include controlling [
 natural sedimentation processes, but only the j
 sediment  generated as a result of man's  activi- j
 ties.                                         j
   Erosion and sediment control requires: (1) a j
 combination of workable laws, regulations, and i
 procedures; (2) up-to-date practices and tech- J
 niques; and (3) responsible people working to- |
 gether. Laws, regulations, and procedures must i
 be based on technological constraints as well as
 environmental, social, and economic needs. How-
 ever, even the best laws, regulations, and  proce-
 dures are  useless unless they are implemented
 properly. This requires thorough understanding
 of up-to-date control practice and techniques, a
 sense of public responsibility, and a cooperative
 attitude on the part of operators and regulatory
 groups.

   EROSION AND SEDIMENT CONTROL
                PRINCIPLES
  Five  basic, commonsense principles govern I
the development and implementation of a sound j
erosion  and sediment control plan for any sur- 1
face coal mine.                                I
 • Plan the  operation  to  fit the topography,
   soils, waterways, and natural vegetation at
   the site (see sec. VI).
 • Expose the smallest practical area of land for
   the shortest possible time (see sec. VI).
 • Apply soil erosion control practices as a first
   line of defense against offsite damage (see
   sec. IV).
 • Apply sediment control practices as a second
   line of defense against offsite damage (see
   sec. V).
 • Implement a thorough maintenance program
   before, during, and after operations are com-
   pleted (see sec. VII).

 These principles apply to both mining and con-
 struction and form the framework upon which
 the erosion and sediment control strategy for a
 particular mining operation is built.

 Preplanning

   This principle  stresses  the need to  plan the
 mining operation to minimize short-term and
 long-term environmental damages. This implies
 siting the operations to avoid damage to critical
 site features, as well as considering site  condi-
 tions, such as overburden properties and topo-
 graphic features, in developing a reclamation
 plan.  Figure  III-l shows a mined area  that has
 been  returned to its former land use  through
 proper reclamation.
   Since the  primary resource (coal)  is  fixed,
 there is little flexibility in deciding where a par-
 ticular mine  is to be sited, other than  to avoid
 a location where the overall environmental cost
 would be greater than the value of the  coal
 recovered. Slightly more flexibility exists, how-
 ever,  in determining how the site will be mined.
 For example, should a natural outslope be exces-
 sively steep  or otherwise  unstable, a  problem
 frequently  encountered  in  the Appalachian
 States, the operator should use a "haulback"
method of contour strip mining rather than con-
ventional contour mining (fig. III-2). The pres-
ence  of a waterway below the coal  outcrop,
regardless of the condition of the intervening
                                              13

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                                Figure 111-1.  Reclaimed mined land.
slope,  could  also, from the standpoint of soil
loss and potential sediment damage, influence
the mining methods used.
  Flexibility also exists in determining the sur-
ficial features (relief, drainage, soils, plant cover,
etc.) that remain after mining is  complete, as
illustrated in figure III-3. To avoid long-term,
postmining sediment problems, these features
should be designed and installed  in a manner
compatible with the  offsite  drainage system,
local climatic conditions,  and the  physical and
chemical characteristics of the  spoil material.
This is accomplished by conducting a thorough
site investigation at the time of the premining
resource (coal)  investigation (sec. VI).  This
information is then used  in determining  what
overburden materials must be segregated  (both
toxic materials  to be buried  and topsoiling
material), the postmining land  use, the allow-
able length and steepness of spoil slopes, the
location  and configuration of the postmining
surface drainage system, and the types of vege-
tation to be used.
   A thorough premining investigation of exist-
ing site features is also an essential first step in
the siting, and design, of roadways leading to
and from the mine. Recommended procedures
for conducting the premining investigation  are
discussed in detail in section VI. By minimizing
damage to critical  features in the siting of a
roadway  and  in  designing the  stormwater-
handling system, both sedimentation and opera-
tional problems can be significantly reduced-
providing utility and safety are also considered.
A well-sited  roadway is one that  avoids cur-
rently or potentially unstable slopes (i.e., areas
containing a high ground water table, thick allu-
vial soils, unstable  bedrock, or old landslides),
minimizes disturbance of highly erosive or plant
toxic soils, reduces cut-and-fill requirements by
following  the ground contour, avoids unneces-
sary stream  crossings, and preserves an ade-
quate,  undisturbed buffer along streams and
other waterways.
   An important factor to be considered in  the
design of the drainage system for the roadway,
                                              141

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   Figure 111-2. Haulback contour mining in Appalachia, used to minimize site disturbance.
•SRSasMtefcsSste'fc ISi
                                                               sJMftSar^Sgsefft-fi'S^i-W'^
                                                               A*",*,&^/'U£*'*?^A^.^?-^'^3F.J*j«:-L.


                                    i       -  -     ...      • .  ,
  Figure 111-3. Mined land returned to approximate original contour and used for farming.
                                    115

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Figure III-4.  Staged reclamation to minimize area of exposure.  (Adapted from W. E. Coates, "Landscape
  Architectural Approach to Surface Mining Reclamation," Research and-Applied Technology Symposium
  on Mined-Land Reclamation, National Coal Association (sponsor), Mar. 1973.)
                                              16

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                                           .   I
 is the location of stable areas on which to dis-
 pose safely of surface, runoff collected and con-
 centrated by the roadway. These include: (1) well
 vegetated and relatively flat areas that will tend
 to slow, spread, and filter the water discharged
 from culverts and  other  drainage structures;
 (2)  well  armored  (bedrock or coarse,  stoneyi
 soil), rough,  and partially  vegetated surfaces)
 that are  highly resistant  to erosion and dissi-1
 pate flow energy by spreading and slowing thej
'runoff; and (3) natural, drainage ways that can
 handle increased flow with little or no increase'
 in channel erosion.                             I

 Scheduling Mining Operations

. ,  The second erosion and sediment control prin-
 ciple is to expose the  smallest practical area of
 land for the shortest possible time. The reason-!
 ing behind this principle is rather simple—1 acre
 of exposed land on a hillside will yield less sedi-1
 ment than 2 acres of exposed land on the  same
 hillside, and an area exposed for 6 months will
 yield less sediment than the same area exposed;
 'for 1'year.                      '     , '   :  '  -}
   The manner in which various mining activi- j
 .ties are scheduled and, .in  the case of area strip I
 miningj-the geometry of the pit will have a major !
 influence on,both the amount of land exposed at
 any one time, and the length of time it remains
 exposed.  The mining activities  having a major j
 effect are,  clearing,  grubbing,  scalping,  and i
 reclamation (fig. III-4).                        j
   The clearing, grubbing, and scalping of exces- i
 sively large areas of land ahead of the  active pit j
 or bench is an unnecessary invitation to  sedi-
 ment problems. These initial earth-disturbing
 activities should progress with the pit or bench,
 and only far enough ahead to prevent a disrup-
 tion in the overall flow of events at the mine.
   Reclamation  should be kept  current  with
 extraction operations and follow as close to them
 as possible. This  reduces  the amount of  mine
 area exposed at any one time and length of time
 the spoil  remains exposed. Scheduling of recla-
 mation operations is  an  essential element in
 controlling erosion and sediment on any surface
 mining operation. Freshly graded areas, particu-
 larly steep or long  slopes, are  highly erodible
•and require quick stabilization. Care should be
 taken to  final grade and  stabilize spoil areas
 promptly, particularly outslopes,  and concen-
 trate land preparation  (clearing, grubbing, etc.),
 extraction, and reclamation activities to as small
 an area as practical.                   •
   Where "head-of-hollow" fills are constructed,
 the face of the fill should be stabilized promptly
 at,the completion of the  construction of  each ]
 step or bench, beginning at the toe of the fill, and I
  progressing upwards  (fig.  III--5);  Staging the
  revegetation operations in this manner provides
  a filter for trapping sediment from runoff com-
  ing from higher unprotected areas, as well as
  preventing rainfall and runoff  from removing
  soil from lower sections of the slope.
    The total amount of land exposed to the ero-
  sive actions of water and wind and the length of
  time the disturbed area remains exposed are
  also influenced by the geometry of the pit or
  bench cut. This fact has been recognized by vari-
 ,pus States  in their regulations. A reduction in
  either the length or width of the pit, or cut, all
Bother factors (i.e., rock strata,  coal thickness,
  etc.) remaining nearly equal, will decrease both
  the area of land exposed and the length of ex-
  posure. This is a particularly significant con-
  sideration when planning an area strip mine.

  Erosion Control

   The third important control  principle is to
 .apply soil erosion control practices as a first line
 of defense against off site damage. This principle
 relates to using practices that control erosion on
 a disturbed area to prevent  excessive sediment
 from being produced. The operator's success in
 preventing sediment from being generated will
 have a, direct bearing on the cost and effective-
 ness of sediment  containment  measures  and,
 ultimately, on the extent of offsite damage from
 , sediment. Control does not begin with the perim-
 eter sediment basin, as is too often thought; it
 begins at the source of the sediment and extends
 down to the basin.
   Soil particles become  sediment when they
 are detached and moved from their initial resting
 place. This  process, which is called erosion, is
 accomplished for the most part by the impact of
 falling raindrops  and the energy  exerted by
 moving water  and .wind, especially water. A
 reduction in the rate  of erosion (soil loss) is
 achieved by controlling the vulnerability of the
 soil to erosion processes or the capability of
 moving water or wind to detach soil particles.
 In humid areas, this  is accomplished through
 the use of "soil stabilization" and "runoff con-
 trol" practices. Soil stabilization practices in-
 clude a variety of vegetative,  chemical,  and
 structural measures used to shield the soil from
 the impact of raindrops  or to bind the soil in
 place, thus preventing it from being detached by
 .surface-runoff or wind action (fig. III-6K Runoff
 control practices, on the other hand, include a
 number of measures  designed  to  reduce the
 amount of runoff that is generated on  a  mine
 site, prevent offsite runoff  from entering the
 .mine _site, or slow. the runoff moving through
 and exiting  from the mine site  (fig. IllrVJ. A
                                              I
                                              117

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          Figure 111-5. Well-stabilized outslope on head-of-hollow fill.
       iyc*

Figure 111-6. Closeup of mine spoil stabilized with vegetation to reduce soil loss.
                                     18

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 more detailed discussion of erosion control prac}
 tices can be found in section IV and in volume IIj

 Sediment Control

,-"_  The fourth principle  is  to  apply sediment
 ^control practices  as  a second line of  defens^
 against offsite damage. Even with the best eroj-
 sion control plan, some  sediment will  be geni-
 erated, and controlling it is the objective of this
 principle.                                    j
    Whereas  erosion control practices  are  dej-
 signed to  prevent soil  particles  from  being
 detached,   sediment  control  involves   using
 practices that prevent the  detached, particle?
 from leaving the  mine  site and getting into
 receiving waterways. This is accomplished by
 reducing the ability of surface  runoff to trans!-
 port sediment and by containing the sediment
 onsite.                                  ,    j
   Sediment control practices are designed to
 slow the flow of water by  spreading, ponding, or
 filtering. By so doing, the ability of the water,
 to transport sediment is reduced, and sediment!
 settles  out of suspension. Commonly used con-j
 trol practices include: (1) the  preservation or!
 installation of vegetated buffer areas dowhslope
 of the mine to slow and filter runoff (fig. 111-8);!
 (2) the construction of small depressions or dikes
 to catch sediment  (particularly coarse-textured
 material) as close to its point of origin as pos-
 sible; and (3) the construction of larger basins
•at  the perimeter of the mine site to capture
 additional sediment from the runoff (fig. III-9).
   The amount of  sediment removed from the
 runoff is mostly dependent upon (1) the speed
 at which the water flows through the filter, trap,
 or basin; (2) the length of time the water is de-
 tained; and (3) the size, shape, and weight of
 the sediment particles.

 Maintenance and Followup

   The final important  control principle is to
 implement a thorough maintenance and follow-
 up operation. This principle is vital to the suc-
 cess of an erosion and sediment control program.
 A site cannot be controlled effectively without
 thorough, periodic checks of all erosion and sedi-
 ment control practices. When inspections reveal
 problems,  modifications, repairs, cleaning,  or
 other  maintenance operations must  be  per-
 formed expeditiously (fig. 111-10).
 1 Particular attention must be paid to water-
handling structures (such as, diversions,
sediment  traps, grade control structures, and

                               ^i^ff^f^K"^'.-'.^t'i>:
                               *j ^wife 'y$jjp', llfe'iCij 'ffyflft*1''-':;,. •;'/: '$(;. , ^Kv" |i«S
                               a'\?''S^j!^;S?"'Vi& ^ ' • •-?,•-••'"" fc ?*•! • '^. '• «S^
             Figure 111-7. Reverse benches or terraces used to control runoff on long slopes.
                                             ! 19

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                 Fill

                area
                                                        cut   i,  :• .  „,.,
                 Figure 111-8.  Vegetative buffer.
                                                                      *&£
                                                                 **^!j#H

                                                           #je^--$-?*£
                                                                ^f-rr;:Sq
                                                                         •1
W-l
A-f.-M
                                                              '"^^]^wm


                                                              '-^J&te*-
                                                          -*5t>'£"?!S*! •!9f-r~-
                                                          •ivf'LJm*-^.^^.
                                                               •i^i?;"^

                                                              :-?&*K#Mr
                                                            ftlf-,
                                                               ... •t£^.:^"?>:

                                                                ,, >%,„ ,J   ' 	#

                                                                  j  J. '  ' ., --.! -"•*

                                                                  - ' • V-I-JJ,'V=«°Sij?~-r-'= "'Tllfe
                                                          -.,,«,"-'»»--,
Figure 111-9. Sediment basin used to trap sediment coming from mine site.
                             20

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  sediment basins) and areas being revegetated.
  Breaches in the structures or areas being revege-
  tated  must be  repaired  quickly,  preferabljy
  before the next rainfall. When sediment contain-
  ment structures fill to capacity, they must b'e
  cleaned promptly, and the sediment disposed df
  in a manner that will not allow it to be reiritrq-
  duced into the drainage  system. Disposal may
  include burying the sediment in the mine, spread;-
  ing it thinly on stable slopes just • prior  to
  seeding and mulching, or placing it up slope be-'
 hind stabilized soil dikes.             ;        I
    The maintenance program must also' consider
 postmining conditions. To avoid the possibility
 of major damage occurring after the coal ha^
 been; mined, the control plan  should cqntairi
, provisions  for removing sediment traps and
 basins from the  drainageways  once a stable
 ground cover has been established on the; site;
 Unless required for other purposes, and the post}
 mining landowner is willing to continue maintej
 nance,  all access roads should be planted with
 vegetation,  and  stable,  open  drainagewaysj
 provided to carry runoff across the right-of-way!
 to stable disposal areas.                       I
Figure 111-10.  Inspection of riser pipe on sediment
                  basin.
                                             21

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                                        Section IV
                                 EROSIOfli CONTROL
   This section presents the basic concepts and
practices associated  with controlling  erosion
at surface mine operations. The section begins,
with a presentation of the basic types of erosion1
that are commonly encountered. These include!
sheet  erosion,  rill  and gully erosion,  stream1
channel  erosion and  wind erosion.  Next, the!
various factors that  influence erosion are dis-t
cussed. They include  climate, vegetative cover,!
soil  characteristics and  topography.  The  re-'
mainder of the section presents the numerous'
practices available to control  soil erosion on!
coal surface mining operations. The practices]
have been organized into two major groupings—!
erosion control practices and soil  stabilization!
practices. In  addition, the  methodology forj
vegetative  establishment  and  maintenance!
requirements of erosion control practices  andi
materials are provided.                       |
                                            i
           TYPES OF EROSION            j

  Soil erosion is the detachment and movement]
of soil by the action  of water,  ice, gravity, ori
wind (fig. IV-1). Of these, erosion by water is!
              by far the problem most frequently encountered.
              This manual addresses itself principally to the
              types of erosion that are caused by the forces of
              falling and moving water. Three basic types of
              overland erosion by  water are  usually recog-
              nized: splash or sheet, rill, and gully.  Stream
              channel erosion also occurs.

              Sheet Erosion (fig. IV-2)
                The impact of raindrops upon a soil surface
              causes  soil particles  to be dislodged.  Under
              conditions of heavy rainfall, the detaching ac-
              tion of the raindrop is an important part of the
              erosion process. Raindrop impact and the result-
              ing splash can throw a soil particle as high as 2
              feet and move it horizontally 4 or 5 feet". A very
              heavy rain may detach as much as 100 tons of
              soil from an acre of exposed surface.1 Rain strik-
              ing a bare soil surface results in the following
              conditions:
              •  Soil structure at ground surface is destroyed,
                and crusting and hardening of the soil surface
                occur.
              •  Soil particles  are detached, displaced,  and
                transported in runoff water.
                                                             / Suspension of
Raindrop impact
dislodging soil
particles
Particlesjcarried
by runoff
water
                                                                soil particles
                                                             y muddying stream
                               Figure IV-1.  Sojil erosion process.
                                             23

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           «n*»
  air:*'*    ™F
  •($•(•
f    :"
V-  ~^#*'
    •^*f'   -^
   _?,, i *sr >

lfC3r  *'.
                  Figure IV-2. Severe sheet erosion from raindrop impact and splash.
                              "*;
•->! •
          ' , . ' : f*. . i .t*6*
   .. H*  •"*>-


                                                   \
                                                   •;^
-------
   Gullies are the result of unchecked erosion
and cannot be removed by tillage equipment.
Gully erosion occurs when water accumulates,
in narrow channels and,  over short periods,!
removes the soil from these channels to depthsj
ranging from 1 or 2 feet to as much as 75 to 100;
feet (fig. IV-4).                               i
  .Figure IV-4. Severe gully erosion on mine spoil.

Stream Channel Erosion                   j

   The credibility of a stream channel is influ-j
enced  by the nature of the bottom and  side
material,  the stream gradient, and the align-
ment.  Runoff water entering into a stream or!
channel not  only transports material, it  also
becomes an eroding agent (fig. IV-5). Stream
channel erosion (scour) results from three proc-
esses:     '

• Hydraulic  action  involves the  force of the
  water striking against the bottom and banks
i  of the waterway. Streams with steep  gradi-
  ents,  unarmored  channels,  and  sinuous
  courses are most susceptible to erosion by [
  hydraulic action.     ...
  • Solution is the actual dissolving of material
    by the water.
  • Corrasion is the hitting or rubbing of soil and
    rock particles in transport against the sides
    and bottom of the channel resulting in the
    detachment of in-place particles. Corrasion is
    most prevalent in fast-flowing streams.

    The nature of the bottom and side material,
  in particular its texture and structure, will influ-
  ence  the  rate  of channel  erosion. Strongly
  bonded, cohesive soils are generally less erodible
  than loose, fine-textured, granular soils.

  Wind Erosion

    Wind erosion occurs primarily when the soil's
 moisture content is lowered,  and wind is able
 to detach  and transport light, dry particles.
 Dust is a problem at many mines.  The major
 source of dust  from wind erosion  at  surface
 mines is generally haul roads. Other sources of
 fugitive  dust  include  excavation  activities,
 blasting, loading, and hauling. Trucks passing
 over dry soil raise dust that is transported by
 wind to offsite areas and directly or indirectly,
 to some extent, into waterways.
     FACTORS INFLUENCING EROSION

   There are four basic sets of factors that deter-
 mine the erosion potential of any area.  These
 are  climate, vegetative cover, soil properties,
 and topography. Although  these  four factors
 are  discussed  separately, it is their combined
 influence that determines the erosion potential.

 Climate

   Precipitation, temperature, and wind are the
 principal  climatic elements that influence ero-
 sion. Precipitation and its associated runoff are
 the most  important of these elements from the
 standpoint  of  erosion  control.  The  seasonal
 distribution, frequency, duration and intensity
 of rainfall that occur vary  for each particular
 region.
   Runoff is that portion of the rainfall or other
 precipitation that makes its way toward stream
 channels as surface and subsurface flows. Sur-
 face runoff occurs only when the precipitation
 exceeds the rate at  which water can infiltrate
 the soil (fig. IV-6).      '
   Temperature influences runoff. Precipitation
 that falls  in the  form of snow does not  create
erosion. However, in the springtime, the combi-
nation of snowmelt and partially frozen ground
results in considerably higher runoff volumes,
thus creating a serious erosion hazard.
                                             25

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                       Figure IV-5. Stream channel erosion.
Rate of
precipitation
EXCEEDS
rate at which
soil absorbs
water
Stream __
   channel;
                                     Soil can
                                     hold no
                                     more water
                           Figure IV-6. Surface runoff.
                                    26

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Vegetative Cover
   Vegetation  plays an  important part  in  re- j
ducing erosion.  When vegetation is  removed |
from  the  soil surface,  the  primary  defense
against soil erosion is destroyed. The benefits of I
a cover of vegetation are:
• The soil is shielded from raindrop  impact,
  thus preventing the removal of soil particles
  and sealing the surface soil.
• The surface cover slows the movement of sur-
  face water, thus giving the water additional
  time to infiltrate into the soil.
• The root system binds the soil together and
  makes it more pervious (fig. IV-7).
                                                            sji^au.  -   ;•;  ...
                                                            •  f";itf~'- -:f- •- ••   :  • ••
                                                             '~:fc' - ' * - " ^: " :>&-; gS-;j '"*"f, -^lif-.- ' ^
                                                    W-
                                             ;.;  is
                                 ^^/^rv'*'1
                                 ;• /.':".'f-^^' •.

                  /:"-''^:- :':v^"^*&is;lfc,ra':'.• '•
                 ':•* ..•>: •--.•••.Sf*,;-,)ff:«-:>m-, *..*L.V
**'  .  ,• /'•'•i. ^'- ".v*-.';:<&-?,.^*v-.n'^idv^
                                 *&*-r* r*r4;:«::»€• -.T»1J


                    Figure IV-7. Soil particles are bound together by root system.

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Soil Characteristics
                  Table \\J-2.-Basic soil textural class names
   Runoff and erosion vary from site  to  site
depending upon the characteristics of a particu-
lar soil. The erosion potential of a soil is depend-
ent on:
•  Soil structure
•  Soil texture
•  Organic matter content
•  Moisture content
•  Permeability
   Soil Structure. Soil structure is the arrange-
ment of particles into groups. The structure of
any  soil  affects the intake  of  water and  air.
Whenever  the surface  layer of soil  becomes
puddled,  crusted, or otherwise compacted, the
danger of runoff and erosion increases. Forested
and cultivated soils often have subsurface layers
of consolidated  material  called  "hardpans,"
which inhibit the downward movement of water.
The  removal of overburden, as in the case of
mining, breaks up hardpan layers and allows for
a more porous and unconsolidated soil to be re-
constructed.
   Soil Texture. Soil texture refers to the sizes
and  proportions of various  sizes  of particles
making up a particular soil. Soil textural  classes
are generally made up of sand, silts, and clays.
Sand particles are the largest,  silts are inter-
mediate, and clays are the finest. The various
sizes of soil particles  and soil textural class
names are given in tables IV-1 and IV-2.2

       Table IV-1 .—Size limits of soil separates

          U.S. Department of Agriculture
                    scheme
         Name of separate
Diameter
 (range)
Very coarse sand3 	
Coarse sand 	
Medium sand 	
Fine sand 	
Very fine sand 	
Silt 	
Clay 	

Millimeters
20-10
1.0 -0.5
0.5 -0.25
0.25-0.10
0 05-0 05
0 05-0 002
Below 0 002

   •Prior to 1947 this separate was called fine gravel. Now fine
gravel is used for coarse fragments from 2 mm to 1.27 cm in
diameter.
   Source:  U.S. Department of Agriculture, Soil Survey Staff,
Soil Survey Manual, USDA Handbook No. 18, Aug. 1951.
General terms
Sandy soils: Coarse-textured soils
Basic soil texture
class names
) Sands
I Loamy sands
             Loamy soils:
                  Moderately coarse-textured
                     soils  	
                  Medium-textured soils .
Moderately fine-textured
soils
Clayey soils: Fine-textured soils . .

<
Clay loam
Sandy clay loam
Silty clay loam
Sandy clay
Silty clay
Clay
                               Sandy loam
                               Fine sand loam

                             I  Very fine sandy loam
                             /  Loam
                             )  Silt loam
                             (.Silt
                Source: U.S. Department of Agriculture, Soil Survey Staff,
             Soil Survey Manual, USDA Handbook No. 18, Aug. 1951.
   Sand, when dominant, forms a coarse-textured
or  "light"  soil that allows water  to  infiltrate
more rapidly. Silts and  clays  make up  fine-
textured or "heavy" soils, and  are often quite
cohesive and slow to erode. These soils are fre-
quently the worst polluters, because fine-grained
particles travel farther and may be held in col-
loidal suspension. Also, the clay-sized particles
are the most difficult to settle out of suspension
and may require tremendously large basins in
order to conform to water quality criteria. Soils
that are high in silt and  fine sand and low in
clay and organic matter are generally the most
erodible.3
   Organic Matter. Organic matter is plant and
animal residue in various  stages of decomposi-
tion. The organic matter content of a soil affects
its erodibility. As the amount of organic matter
increases, the ability of the soil to absorb sur-
.face water increases and runoff is reduced, thus
minimizing erosion.
   Moisture Content. The moisture content of a
surface soil is a reflection of its moisture-holding
capacity. The ability of a  soil to hold water de-
pends  on its texture, permeability, depth, and
organic matter  content. Soils that are able to
hold large quantities of water are desirable from
a plant growth standpoint, although some clays
with excessive moisture-holding capacity could
be a problem. Soil wetness also influences run-
off. As a soil fills with water, runoff increases.
                                               28

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   Permeability. The permeability of soil refers
to its ability to allow water and air to move
through it. Soils with a high degree of perme-
ability on  a short slope may have slow runoff,
while a soil with less permeability on an identi-
cal slope may have rapid runoff.

Topography

   Topographic considerations  for erosion con-
trol include slope steepness and length. As slope
steepness  increases, there is a corresponding
rise in the  velocity of the surface runoff, which
in turn results  in  greater erosion (fig. IV-8).
A doubling of the velocity of water produced by
increasing  the degree  and length of the slope
enables water to move soil particles 64 times
larger, allows it to carry 32 times more  soil
material, and makes the erosive power, in total,
4 times greater.'
  Long, unbroken  slopes allow surface runoff
to build up and concentrate in narrow channels,
producing rill and gully erosion. For equal areas,
doubling the length of a slope increases the soil
loss 1.5 times.  Long slopes in gently sloping
terrain will also erode easily unless broken up by
diversions, structures, or other means.
            RUNOFF CONTROL

   Stormwater runoff is the principal cause of
soil  erosion.   Stormwater  runoff  control  is
achieved through the proper use of vegetative
and structural practices, and construction meas-
ures that  control  the  location, volume,  and
velocity of runoff, in combination with a sound
program for scheduling various mining opera-
tions to minimize  problems associated with
seasonal climatic fluctuations.  Proper storm-
water handling for erosion control can be accom-
plished in one or a combination of the following
ways:

•  Reduction and detention of the runoff
•  Interception and diversion of runoff
•  Proper handling and disposal of concentrated
   flow
Figure IV-8. Steep slope and fine-textured, structureless nature of a loessial soil contributed to severe erosion
                                   at this mine in the Midwest.
                                              29

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 Reduction and Detention

   A reduction in both the amount of runoff and
 its speed of movement can be accomplished by
 staging the operations to reduce the time and
 area  of  exposure, by manipulating the  slope
 length and gradient  to reduce the velocity of
 flow and rate of runoff, and by manipulating the
 surface soil to detain the water and to increase
 the infiltration rate.
   Staging Operations. The staging of clearing,
 grubbing, scalping, grading, and revegetation
 operations to minimize the amount of disturbed
 surface area is an effective way of reducing the
 volume of surface runoff.  Barren soil produces
 much more surface runoff than a soil that is well
 protected with vegetal cover. The various stages
 of the mining operation should be scheduled so
 that clearing, grubbing scalping, grading, and
 revegetation  are  kept concurrent with extrac-
 tion operations, and a minimum area is exposed
 at any one tune. To the extent possible, areas of
 natural vegetation should be preserved to act as
 buffer zones  along streambanks, below  spoil
disposal sites, around the perimeter of disturbed
areas, and above and below access roads. These
areas will slow and filter the runoff coming from
the disturbed areas and, thus, trap some  sedi-
ment.
   Grading and Shaping of Soil Surface (fig.
 IV-9).  The soil surface can be graded and shaped
 to reduce and detain runoff. This includes rough-
 ening and  loosening the soil, mulching and re-
 vegetation, and topsoiling and soil amendment.
 All final grading should be performed on the
 contour. Backblading that results in a smooth
 compacted surface should always be avoided.
   A properly roughened and loosened  soil  sur-
 face will enhance water infiltration,  slow the
 movement of  surface runoff, and benefit plant
 growth (fig. IV-10).  Common methods of loosen-
 ing and/or roughening a soil  surface include
 scarification, tracking, and contour benching or
 furrowing.  Other methods being practiced in-
 clude  gouging,  dozer  basins,  and  chiseling.
 Scarification is usually accomplished by discing
 or harrowing along the ground contour, but can
 also be performed by a crawler tractor equipped
 with grosser  bars,  or by dragging the bucket
 teeth of a front-end loader over the ground.
   Tracking is performed on steep slopes where
 equipment  cannot be safely moved along  the
 ground contour (fig. IV-11).  It is  accomplished
by running a cleated  crawler  tractor  up and
down the slope. The cleats leave shallow grooves
that run parallel to the contour.
  Contour  terracing (benching), or furrowing,
                                                                              Culvert with
                                                                              rock as an
                                                                              energy
                                                                              dissipator

            Haul road
                                  Perimeter dike i


                                        Vegetative buffer  ^r


                         Figure IV-9. Grading and shaping of soil surface.
                                            30

-------
 -'.'  ' '•'-.-'-~•
                    Figure IV-10. Properly roughened (along the contour) fill slope.
                                                ''*>"-*^™^a***glgQ98*
                                                * • •;/,' ^t"***^ ,i*Jx?T,.:ffr^. •ji?*d%gtmjf'*i*
                                                "W-^<:/V^2iii|fesW»K-^.; -~f-, -*JZ*sr-s&

                          '^•'•i^^i^M£^^^^''''^^^.-'^^^^^^mM^''M

                           Figure IV-11.  Mine spoil roughened by tracking.
is performed in conjunction with other roughen-
ing techniques on long  slopes to disrupt and,
slow surface runoff. Terracing is done with a
bulldozer running parallel to the contour and
allowing dirt to dribble off the end of the blade
creating small depressions  and  ditches  that!
interrupt the  flow of  surface water  down the
slope. Furrowing is  accomplished by  similarly
plowing parallel to the contour. In both cases,
the resulting depression must run along the con-
tour of the ground, otherwise the intercepted
runoff will concentrate in lower areas and result
in gully erosion.
  Gouging is a surface configuration composed
of many depressions, and is accomplished with a
specially constructed machine that has hydrau-
                                              31

-------
 lically operated disc scoops, 25 inches (63.5 cm)
 in diameter, that alternately  raise and  lower
 while being drawn by a tractor. The three disc
 scoops create elongated  basins on the contour
 approximately 14 to 16 inches (35.5 to 40.6 cm)
 wide, 3 to 4 feet (0.91 to 1.21 meters) long, and 6  ,
 to 8 inches (15.2 to 20.3 cm) deep. This pattern
 is amenable to gradual slopes and flat areas. It  '.
 creates a cloddy  seedbed ideal  for broadcast
 seeding.                                       :
   Dozer basins are  large depressions designed
 to accomplish what terracing is intended to do,  :
 but  without the characteristic precision,  haz-
 ards, and expense. Dozer basins  are 15 to 20
 feet  (4.56 to 6.08 meters) long, and are formed  ;
 by dropping the bulldozer blade at an angle at
 intervals  and bulldozing on the contour.  The
 resulting basins are approximately 20 to 25 feet
 (6.08 to 7.6 meters)  from center to center, and
 are about 3 to 4 feet  (0.91 to 1.21 meters) in
 depth. Basins are constructed  in parallel rows
 with about 20 feet (6.08 meters) between rows.  ;
 Precipitation  intercepted  within  each   mine
 drainage accumulates  in  the basin bottom in  :
 quantities sufficient to saturate the basin limits
 thoroughly. The increased soil moisture avail-
 ability assures the establishment  of a nucleus
 stand of vegetation  the  first growing season;
 from this nucleus, it  can spread between basins
 to make a complete cover.
   Deep chiseling is  a surface  treatment that
 loosens compacted spoils for a depth of 6 to 8
 inches (15.24 to 20.32 cm). The process creates
 a series of parallel slots on the contour to impede
 water flow effectively and increase the infiltra- .
 tion rate. Deep chiseling uses a modified Graham-  '
 Hoeme plow with 12 chisels to form a rough
 cloddy seedbed. This treatment is effective on
 relatively  flat slopes, and is very  beneficial in
 loosening spoil before gouging or following dozer
 basin construction.
   In addition to the mechanical measures de-
 scribed above, the permeability of the surface
 soil  can be enhanced  through  topsoiling and
 soil conditioning. Topsoiling consists of spread-
 ing a top layer  of soil material  capable of sup-
 porting plant growth.  The best soil material
 available for plant  growth should be identified
 prior to mining, segregated, and saved during  .
 overburden removal.  Soil  amendments such as
 those found in  lime  or organic matter can be
 worked into the surface soil to loosen particle
 bonds, promote plant growth, and increase infil-
 tration,                                        i
   The  prompt  establishment  of  a cover  of
vegetation and/or the placement of a fibrous,
organic mulch  on freshly graded soil surfaces
\vill also detain and reduce surface flow. In addi-
tion, it will stabilize the  soil in two ways.  It
 provides protection from the impact of raindrop
 splash, thereby preventing the soil surface from
 being compacted and sealed. Also, it impedes
 the flow of surface runoff and reduces the veloc-
 ity, which in turn reduces erosion and increases
 infiltration.
   Manipulation of Slope Length and  Gradi-
 ent. The rate of runoff and, thus, the rate of soil
 erosion can also be controlled by manipulating
 the gradient and length of slope. This measure is
 particularly important in area mining and moun-
 tain top mining, in that considerable flexibility
 often exists in shaping the spoil areas.
   Slope design should be based on the credi-
 bility  of the surface soils as well as stability
 against landslides. Restoring the approximate
 original contour may not be desirable in all cases.
 A reduction in relief and an overall flattening of
 the topography may be desirable from an ero-
 sion and sediment control standpoint. It must
 be remembered that shorter or flatter slopes are
 less erodible.
   Where there is little flexibility as to the over-
 all configuration of the slope, as is often the case
 with contour mining, diversion structures, such
 as reverse  benches or terraces, ditches, and
 dikes, can be deployed above, on top, and along
 spoil slopes to decrease the overall length of the
 slope (fig. IV-12 and IV-13).
   The shape of a slope also has a major bearing
 on soil loss and the potential for offsite damage
 due to sediment. Assuming the gradient re-
 mains constant,  the base of a  slope is more
 susceptible  to erosion than the top. This is be-
 cause the runoff becomes more concentrated and
 picks up momentum as it approaches the base.
 Constructing a convex slope magnifies the prob-
 lem, whereas a concave slope reduces it. Leaving
 a relatively flat area near the base of the slope
 not only reduces erosion, it also traps sediment
 coming from upper portions of the slope.

 Interception and Diversion

   Another key concept in controlling soil ero-
 sion is to intercept runoff before it reaches a
 critical area and to divert it to a safe disposal
 area.  Interception and diversion  are  accom-
 plished through  the  use of various diversion
 structures,  including reverse benches  or ter-
 races, ditches, earth dikes, and combined ditch
 and dike (diversion) (fig. IV-14).  Section I, vol-
ume II, contains information on  the design,
construction, and use of various types of diver-
sion structures.
   Interception and diversion practices perform
two important functions at surface coal mines;
they:

 •  Isolate onsite critical areas (i.e., raw  spoils,
                                             32

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  partially stabilized  spoils, highwall,  access
  roads, and other areas) from off site runoff
• Control runoff velocities on steep or long spoil
  slopes and abandoned access roads

  By placing a reverse bench or ditch above the;
mine site, offsite runoff can be intercepted and
diverted around the disturbed area or to struc-
tures that will safely carry the runoff through
the mine. The use of perimeter diversion struc-
tures is an especially important erosion deter-
rent at contour strip mines.
  Diversion structures can also be used to con-
trol runoff generated within the mine. On exces-
sively long or steep slopes, reverse benches are
often used to protect lower portions of the slope
from erosion due to runoff.  As with perimeter
structures, the  internal  diversion  structure
intercepts runoff coming from higher elevations,
thus preventing it from  reaching the critical
lower slope, and diverts it to an offsite disposal
area or a downdrain structure (fig. IV-15).
  Proper design, construction, and maintenance
of diversion structures are musts. They must be
designed and constructed to  carry  the inter-
cepted runoff at nonerosive velocities.
  Diversion
  dike
           Slope bench
                                Reverse
                                bench
                                         Concave  slope
                            Figure IV-12. Slope reduction measures
                                          I 33

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 *vf',"Stw:..T™*'

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  ^'i' .wv^'Xg^^ft^'
  fc.«&»H 1 :; .m:±J^X£
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                      rytf.^x.1
                      '* '*•  '•  'v.-,V*'•**•!
                         j^A: jit •«r"ii6*iS'*'!* "rTjij,
*'£• ti-'r.'jf  ^. - ^^^ *?-5**fl

^^-y'.-. "^B^rra^
 " ^;". r^r f ,.«f#> i^ ^ * * !V ^.f/' ^
«. (.' »r^j,Sr «»*"»*; .jj? ; •."  •".  .
'tJ'^iSfi*-"*''   ilrw*""g*;i€
                                              '• -''..-•"-**I '*'"  " ' K •*'"".^' '_"'-'" '•' '   ** '^ , "' "^
  ^  ,.*'     '-  tf"  ;"  -* ! $F - :_ V^'j^W'i%frA«' ik iS^* -''^j^W^^'fti1!,?^1''- jfr- ^^^"B'^.,, - '^^'^"^^^^^f^ -


   •• V^1'-- ^'.V>^^^;>^
Reverse

bench
Haul road
Vegetative

buffer area
                     Figure IV-13.  Diversion structure^ (terraces) on long, steep slopes.
                           Figure IV-14. Interception'and diversion measures.
                                                  34

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                                                              A1^**'-, •' -,>««™«BM'-V •• ;C -4 i*JS'> • - -.'J
                           ^M-
                             Figure IV-15. Newly constructed diversion.
 Handling and Disposal of
 Concentrated Flows
   The construction of diversion structures and
the interception  (by  mining) of drainageways
will necessitate the handling and disposal  of
concentrated flow.  The measures taken in han-
dling and disposing of this highly erosive runoff
will have a major  influence on  the amount  of
soil erosion occurring both  within and down-
slope of the mine site. Both soil stabilization and
runoff control are important factors in the
proper handling  and  disposal of  concentrated
flow.
   As with other major categories of runoff con-
trol, proper handling and disposal of concen-
trated flow involves the  use of practices that
reduce the rate of  runoff and, as a result,  its
ability to detach and transport soil particles.
   In handling concentrated flow, the objective
is to detain the runoff by:

•  Increasing the flow distance
•  Decreasing the flow gradient
•  Obstructing the flow

   The flow distance can be controlled by con-
structing the drainageway as long as it is prac-
ticable without causing the water to spill out of,
or erode, the channel. For manmade drainage-
ways, the flow gradient can be controlled in the
same manner. In natural and in manmade drain-
ageways, the grade can also be controlled by the
construction of flumes or other flow barriers
across the channel. These grade control struc-
tures also serve to obstruct the  flow and, thus,
slow its movement. Bends in the channel, either
manmade or natural, also impede the flow.
   The placement of debris, such as rock riprap,
in the channel  to obstruct and dissipate  the
energy of the flow is also an important control
measure.  Figure  IV-16  shows  a  riprap-lined
drainageway. Critical points for the placement
of energy dissipators are the areas below grade
control structures, below outfalls, and along the
outside of bends in the channel.  These controls
both reduce the ability of the concentrated flow
to cause erosion and shield the channel against
erosion.
   Impoundments are also an  important  means
of obstructing flow. They are constructed by
excavating  a  depression in the  channel or by
damming it. Releasing impounded water at a
controlled rate over a prolonged time is a prac-
tice used to reduce flooding and channel erosion
in downstream areas. In addition, the impound-
ment will also trap sediment. Sediment basins
and other sediment traps are discussed  in  the
next section.
                                              :35

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          Figure IV-16.  Stone riprap waterway lining used to dissipate flow and protect channel.
  The conveyance of concentrated flow down
steep slopes is also an important erosion control
aspect of stormwater handling. Structures used
to accomplish this safely include various types
of pipes, flumes, sectional downdrains, and flex-
ible downdrains. (figs. IV-17 and IV-18). The
best type of structure to be used will depend on
site factors and the required service life. Design
considerations  for downdrain structures  are
provided in section I, volume II.
  Proper techniques for disposing of concen-
trated flow  collected in diversion structures
include, where applicable, spreading the concen-
trated flow into nonerosive sheet flow through
the use of a level spreader, and the installation
of an energy dissipator at the discharge point
to dissipate the flow and spread it onto a stable
surface. It is extremely important that the dis-
posal area be well stabilized with vegetation and
be conducive to sheet flow, rather than concen-
trated  flow. When possible, it is  also desirable
to discharge the water above a  drainageway,
rather  than directly into it, so as to use the
intervening vegetated ground to slow and filter
the runoff further.
   Other information on the use, design, and con-
struction of level spreaders, energy dissipators,
downdrains,  and other  water-handling  and
disposal structures can be found in section I,
volume II.

                                              36

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                           Figure IV-17. Concrete ijialf-round pipe downdrain.
      ^&&i





if
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            SOIL STABILIZATION


   Soil stabilization is the other means of pre-
 venting soil  erosion.  Whereas runoff control
 practices are designed to manage rainfall runoff
 in a way that reduces its ability to  cause soil
 erosion, soil stabilization practices are designed
 to protect  the soil from  the erosive action of
 falling rain, ensuing runoff, and wind. Protec-
 tive shielding of the  soil surface from the full
 force of impacting raindrops and the hydraulic
 and abrasive action of moving'surf ace water and
 wind is achieved by binding the soil particles
 together to form a mass that is less easily dis-
 placed, and by anchoring the soil in place. Well-
 established vegetation, for example, performs
 all of  these functions. The leaves, stems, and
 other above ground portions of vegetation,  as
 well as the organic litter that collects on the
 ground surface,  shield the soil surface,  while
 the roots bind and anchor the soil. Surface cov-
 erings of straw, hay, woodchips, gravel, riprap,
jute netting, and other material also serve  to
 shield  the soil.  Other nonvegetative material,
 such as chemical emulsions, can be used to bind
 and anchor the soil particles.
  Stabilization measures may be either vegeta-
tive or nonvegetative, and short term  or long
 term. Vegetative stabilization refers to the use
 of different types of vegetation to protect the
 soil from erosion. Nonvegetative stabilization,
 on the other hand, refers to a multitude of prac-
 tices that use materials other than vegetation
 in preventing soil erosion. Keep in mind, how-
 ever, that a combination of both vegetative,and
 nonvegetative measures is often required.
   Short-term stabilization, also termed tempo-
 rary stabilization, refers to the use of practices
 that  provide  protection for  a  short period of
 time, usually less  than 1 year. Long-term, or
 permanent  stabilization, involves  the use  of
 long-lived vegetation or a durable material, such
 as rock, concrete, or asphalt, to protect the soil
 against erosion for more than 1 year.

 Vegetative Stabilization

   Provided proper care is taken in its establish-
 ment,  vegetation is the most beneficial  and
 durable  soil stabilizer (fig. IV-19).  It  forms a
protective cover that shields the ground surface
from  the direct impact  of falling rain,  and its
roots bind and secure the soil particles. As noted
earlier,  it also controls  runoff by  slowing the
flow of  water  along the soil  surface and by en-
abling the soil to absorb  more water. By re-
ducing  the amount of runoff and its speed of
movement,  the  ability of  the runoff to carry
away detached soil particles is also decreased.
                          'i', '. J"11'." '* 'C	,*'	rijf	,!ii',»o:lp '«ft'«yi;--..,' "  	sjt111' -rsM1.,^,:,!' ,
                          /il  nil  »^'ii, ... . - nl* .151(11'! 1	n	H	I	['III. V '•	""'"  ' 1-'',! *r!JwL"'J* I1-  '
                          s-•  ";'"',:  ,,;:'-,=, „;,:., •> !i««,,,
-------
   Long-term vegetative stabilization is accom-
plished by the proper planting of various combi-
nations of grasses, legumes, shrubs, and trees.
The type and mixture of individual plant species
to be used will depend on soil and moisture con-
ditions, climatic conditions, erosional stresses,
and postmining land use. Selection and estab-
lishment of vegetation is discussed later in this
section.
   Short-term vegetative stabilization involves
the use of low-cost, quick-growing perennial and
annual plants, usually grasses,  to provide pro-
tection for a short period of time  (fig. IV-20).
This form of stabilization is often used to pro-
tect stockpiled topsoiling  material. It is also
used for temporary stabilization of spoil graded
in late spring or  fall  when .more, permanent
stabilization cannot be performed properly.
   Vegetative  establishment is covered later in
this section.

Nonvegetative Stabilization
   Like  vegetative measures,  non vegetative
practices  are used to reduce the susceptibility
of mine soils to erosion.  It is difficult to separate
the two major types of stabilization, in that they
are often used together. An important point to
remember is that nonvegetative stabilization is
used to reinforce  vegetative  measures. Where
yegetation will provide adequate long-term soil
protection,  long-term nonvegetative  stabiliza-
tion is not required. Where vegetation will pro-
vide partial, protection,  as is often  the case in
areas  subject  to  concentrated flow  (such  as
found in a drainageway), a combination of the
two types of stabilization is  desirable. On the
other hand,  should vegetation not be able to
provide any protection, such as on the bottom or
bed of a stream, nonvegetative stabilization is
the  only protective  treatment available  (fig.
IV-21).
  : Nonvegetative  stabilization covers a  wide
assortment of  short-term  and long-term soil
stabilization practices, which vary considerably
in their cost-effectiveness and ability to  with-
stand erosional stresses. As a general rule, it is
probably best to stay with measures that  have
proven successful in the field. New products or
practices appearing  worthwhile  and  offering
.possible  cost  advantages  should  be demon-
strated  on  test plots before being employed
extensively.
                                             ISrtPf. Wi"ft: iS^fS^w
                                             mffifffwviJ&if *»i til4!it£:*i&;ffv=-!fc
                                             ifisv^tK               «
                   Figure iV-20. Outslope stabilized with short-term annual grasses.
                                              39

-------
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    •*
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                                                      .i-^ai^^iBag
          Figure IV-21. Newly seeded and mulched area adjoining ditch lined with stone riprap.
   Short-Term Measures. Mulching and chem-
 ical stabilization are two major types of short-
 term, or temporary, nonvegetative soil stabiliza-
 tion (fig. IV-22). Both are employed to provide
 protection  against excessive soil  erosion  for
 periods of less than 1 year.
   Mulching.  Mulching with organic materials
 such as straw, hay, woodchips, wood fiber, and
 other natural and manufactured products is the
 most popular means of providing short-term soil
 stabilization. Mulch is used in the establish-
 ment of a vegetative ground cover to protect
 the  seedbed  from excessive  erosion prior to
 germination of the seeds and until the new vege-
 tation is sufficiently established.  The mulch
 provides a favorable environment for seed ger-
 mination and plant development. Mulches can
 also be used in place  of short-term vegetative
 stabilization  to  protect  temporarily  against
 excessive soil loss prior to the preparation of a
 seedbed. Some mulch materials,  in particular
 straw and hay, require stabilization to prevent
 them from being uncovered by wind and water.
This is accomplished by applying  asphalt  or
                                  chemical tacks that bind  the  mulch  material
                                  together and to the soil surface or, in the case of
                                  straw and hay, by crimping. When performed
                                  along the ground contour, crimping is doubly
                                  beneficial in that it produces a surface texture
                                  that inhibits surface runoff.
                                    In areas subject to concentrated flow,  net-
                                  tings of fiber glass, plastic, and other  material
                                  stapled securely to the ground may be  required
                                  to keep fibrous organic mulch material  from
                                  being removed. Jute netting is usually utilized
                                  to stabilize drainageways. When  properly in-
                                  stalled, it is difficult to remove and, because of
                                  its bulky and fibrous nature, it protects the soil
                                  surface and  provides a good environment  for
                                  seed germination.
                                    Chemical stabilization.  Chemical  soil  stabi-
                                  lizers are designed to coat and penetrate the soil
                                  surface and bind the soil particles together (fig.
                                  IV-23). They are used to protect bare soil slopes,
                                 not subject to traffic, from wind and water ero-
                                 sion during temporary establishment of a seed-
                                 bed. Chemical stabilizers are used both in lieu of
                                 temporary mulch material  and in  conjunction
                                              40

-------
                                                                           '!<      I,!///.
                                    Figure \\l-22.\ Straw mulch.
                                                                 ^-; ;jr**g*;sg
                                                                 ?;'>>>.,/>•. 	
                                                                   •• -*^ .••*%"'^f~ '.^^S^^ef^x^' ^^'^ ft ^> ^3

                                                                     :"   ! :r:*sfeaS~L3S5'5%*fe!i
                                                                                 '. , _; -. '^"'^"''X'^^f^Jjl?*1

                                                                                    ""-VV- /^;^
                    Figure IV-23.  Chemical stabilizer being applied over straw mulch.
with the  material to act as a mulch tack and
soil binder.
   Chemical stabilizers generally work best on
dry,  highly permeable spoil, or in-place soils
subject to sheet flow rather than concentrated
flow. It is recommended that chemical soil stabi-
lizers be tested on small, representative plots of
ground before selecting a mixture of chemicals
and water and an application  rate, or before
deciding to use these  chemicals extensively in
stabilizing mine soils. As a general rule, chemi-
cal stabilizers do not provide protection for as
long a period of time as straw,  hay, and other
organic mulches.
   Section I, volume II, contains additional in-
formation on short-term stabilization measures
and products.
   Long-Term  Measures.  Long-term,  non-
vegetative soil stabilization  is required when
vegetation alone cannot withstand the erosional
stresses imposed  by surface runoff and when
vegetation is not  adaptable to the chemical,
moisture, or traffic conditions occurring in the
soil or on the surface to be stabilized. Areas at
surface mines requiring such treatment include
roadbeds, waterways, and toxic or  excessively
wet soil surfaces.
   Long-term measures include nonstructural
practices, like mulching, and structural prac-
tices, such as paving, channel lining, and grade
control.
  Mulching. Mulching practices involve the use
of nonbiodegradable material, such as fiber
glass and various  plastics, to protect seedbeds
                                              41

-------
during the critical germination and early plant
development period, and to act as a reinforce-
ment following establishment of the vegetative
cover. These materials include  nettings and
loose,  stringy products that, when applied to
the seedbed, become securely enmeshed in the
vegetation at the ground surface and  in the
rootmat. Light applications of crushed stone or
gravel will perform a similar function.
  Stone surfacing.  To stabilize  highly toxic
surfaces,  or excessively wet seepage areas on
slopes, a heavy application of durable crushed
stone, gravel, clinkers, or "red dog" is often
warranted. The best cure for these problems, of
course, is to dispose of the overburden and man-
age the drainage in a manner that prevents such
problems from occurring.
  Crushed stone, gravel, clinkers, and red dog
also are used to surface roadways  (fig. IV-24).
In addition to securing  the soil, such treatment
increases  the bearing capacity of the roadway,
provides for continuous all-weather  use, and
decreases the likelihood of traffic damage and
related accelerated soil erosion.
  Channel stabilization. Channel  stabilization
is usually not as complex a problem at surface
coal mines as it is at large, urban construction
sites. For the most part, structural stabilization
practices  involve the use of stone riprap and
other durable material  to stabilize  ditches and
 other  manmade  waterways.  Where  natural
 streams are severely affected by mining, either
 due to disturbance of the channel or increased
 surface runoff, sophisticated and costly struc-
 tural measures are often required to protect the
 channel from erosion.
   Channel stabilization structures are used to
 maintain channel alignment (i.e., prevent ero-
 sion of the sides of the channel) and/or maintain
 channel gradient  (i.e., prevent scour of the chan-
 nel bottom). Revetments and check  dams are
 the structures most commonly used at mines to
 prevent  channel  erosion. Revetments  are de-
 signed to shield the channel from the hydraulic
 and abrasive action of concentrated flow. Gener-
 ally, these structures are built of stone riprap
 obtained from the mine site and placed in the
 bottom of the  channel at  critical locations to
 prevent down-cutting. Where the sides of the
 channel cannot be stabilized with vegetation
 alone, the stone  is carried up the sides of the
 channel to form a complete channel lining. The
 stone riprap should be sandstone, limestone, or
 other durable rock of a size that cannot be re-
 moved by the runoff. Large voids between rock
 fragments should be clinked  with smaller frag-
 ments to provide  a dense cover. When heavy or
 sustained flows must be handled, a graded sand
and stone filter, or filter cloth, should be placed
under the structure, securely against the soil
                                                                                       * "* ,~t

                                                                                   t    "  *'-,:!*
                          Figure IV-24. Access road with aggregate surface.
                                              42

-------
 surface to prevent the upward movement of soil
 particles due to hydraulic action. Wire baskets
 filled  with  stone (gabions),  various  concrete
 blocks, bags filled with a mixture of sand and
 cement, and nylon mattresses filled with a sand/
 cement grout (Fabriform® ) are also used to con-
 struct revetments  in waterways (fig. IV-25).
 These products and materials are generally only
 used to stabilize highly critical areas,  such  as
 natural streams or stream realignments. Where
 good riprap stone is  not available at the mine
 site, cost considerations may warrant the use of
 certain material in ditches  and other  areas  in
 place of stone riprap.
   For environmental and esthetic reasons and
 to minimize maintenance requirements, vegeta-
 tion should be used with structures whenever
 possible. Where sustained,  heavy flow is not
 present, revetments constructed of loose stone
 riprap, or thin, stone gabions provide an environ-
 ment for the growth  of vegetation  within the
armored portion of the channel.
   Revetments required to protect critical areas
in stream channels, and occasionally subjected
to heavy flow, should be designed by an engineer
 and be installed in accordance with construction
 specifications.
   Unlike revetments, which can be used to pro-
 tect  the entire channel or its  sides or bottom,
 check dams are designed to protect only the base,
 or bottom, of the channel from erosion.  These
 structures are placed across the channel at inter-
 vals  along  the alignment to inhibit physically
 the moving water from eroding the bottom of
 the channel.  They generally consist of a rela-
 tively narrow strip  of stone riprap laid across
 the channel. Logs and lumber are also used to
 construct check dams. At surface mines, these
 structures are used to control erosion in ditches,
 and  other  constructed  drainageways, having
 steep gradients or long grades.
   Additional  information  on long-term  non-
 vegetative measures can be found in sections I
 and 11, volume II.

 Areas To Be Stabilized

   All areas that are in any way disturbed by the
mining  operations must be stabilized. Water-
ways  that will have  to handle  increased flows
                               Figure IV-25. Stonej gabion structure.
                                             43

-------
 may also need to be stabilized. However, the
 major emphasis in stabilization must be placed
 on three critical areas that are particularly sus-
 ceptible to  erosion—roadways, fill slopes, and
 stream channels.
   Roadways. Roadways are a major source of
 sediment at surface coal mines. Haul roads at
 contour mining operations are a particular prob-
 lem since much of the drainage and runoff from
 the bench and other disturbed areas make their
 way to the  haul road. Roadside ditches, safety
 berms, inlets, outlets, cut-and-fill areas, and the
 actual road  surface are extremely susceptible to
 erosion.
   Water-tolerant and erosion-resistant  vege-
 tation should be used for stabilizing roadside
 ditches. However, where high velocities are en-
 countered, dumped or placed stone riprap will
 provide additional long-term protection. Culvert
 inlets and outlets also require a layer of stone
 riprap  or  other resistant, energy-dissipating
 material.
   Safety berms present several problems. Stabi-
 lization with vegetation and, in some instances,
 other material is necessary to reduce soil losses.
 Roads should be pitched away from the berm,
 toward the  cut slope, to  avoid undercutting by
 water. The berm should be properly compacted,
 and, when concentrated  water is handled, rock
 mulches should be used to provide temporary
 stabilization until a vegetative  cover can be
 established.
   Road surfaces should  be  stabilized by  using
 nonvegetative material such as rock aggregate,
 clinkers, red dog, or other durable material that
 can slow down water and withstand truck, traf-
 fic.  This stabilization is  also important for
 controlling dust on haul roads.
  Slopes. Prompt and effective stabilization of
 cut-and-fill slopes is especially important in con-
 trolling soil  erosion. Cut slopes greater than 2:1
 (50 percent) place severe limitations  on the
 ability of plant roots to hold and bind soil par-
 ticles. As a rule of thumb, a 2:1 slope is assumed
 to be the maximum slope upon which vegetation
 can be established and maintained satisfactorily.
 However, maximum vegetative stability cannot
 be attained  on slopes steeper  than 33  percent
 (3:1). The maximum-slope rule should  only be
 applied to ideal soil conditions where the soil is
not highly erodible and has adequate moisture-
 holding capacity. In situations where vegetative
 measures, such as grasses and legumes, fail due
 to slope steepness, a blanket of crushed stone or
 other durable material will be required to stabi-
 lize the soil.
  Fill material can be manipulated as previously
discussed so that excessive slope lengths and
steepness are  avoided,  thus improving, the
 chances for soil-holding vegetation to become
 established. Fill slopes should remain accessible
 to maintenance equipment. Seeding of cut-and-
 fill slopes should follow closely behind the grad-
 ing operations. Large boulders  and rocks and
 debris can be located at the toe of the fill slopes
 to provide support and reinforcement. This will
 provide a more uniform slope, and make it less
 susceptible to  voids where fills and gullies can
 form.  Scalped material can be windrowed  in
 front of the toe to act as a filter for sediment.
   Stream Channels. Waterways downstream
 from surface mining operations  are sometimes
 subjected to large increases in the volumes  of
 surface runoff. These large volumes of surface
 runoff and the associated increases in velocity
 render the waterway highly susceptible to ero-
 sion.
   Vegetative measures for stabilizing banks  of
 stream channels involve the use of select grasses
 and legumes that are tolerant of wet conditions
 and resistant  to high  water velocities. Table
 IV-3 gives the maximum permissive velocities
 for various types of  vegetative channel linings.
   In certain places  within waterways, vegeta-
 tive practices alone  are not enough to prevent
 erosion. Structural devices must  be used to pro-
 tect the waterway from scour or erosion.
   Critical areas along streambeds that may
 need structural stabilization include the outside
 of bends where the  flow  impinges  or  impacts
 against the streambank, restrictions in the chan-
 nel, junctions  where tributaries enter the main
 channel, and places where the channel gradient
is excessive (fig. IV-26).
   Revetments  are useful in areas  where it  is
necessary to  protect  the  streambanks.  The
material most commonly used for this  purpose
is stone riprap, which  is durable,  heavy, and
 flexible. Also, it generally is readily  available at
many mine sites. Gabions and revetment mat-
tresses are also often used. In addition to these
materials, MONOslabs™, poured concrete, con-
crete block, and sandbags filled with  a sand-
cement mixture are sometimes used. The use of
these materials is discussed in volume II.
   In some areas, it may be necessary to protect
 the  streambed as well as  the  streambanks.
 Grade  control structures are used for this pur-
 pose. These structures physically prevent the
 streambed from being eroded and slow the flow
 of water.
   A grade control structure consists of durable
 material placed, on the  bottom of the channel.
 It can  be a narrow strip of riprap stone placed
 across  the channel, or it can be a complete lining
 of the  channel (fig.  IV-27). Materials  used to
 construct revetments  are also  used to  build
 grade control structures. Common uses of grade
                                              44

-------
 control structures include  riprap  energy  dis-'
 sipators placed at outfalls of stormdrains;  rip- i
 rap check dams placed at regular intervals along I
 a waterway; and revetments of riprap, concrete,
 gabions, Fabriform®, or other material for lining
 streams and drainageways.


       VEGETATIVE ESTABLISHMENT

   The revegetation  of mine spoils and other
 disturbed areas using, for the most part, soil-
 binding grasses and legumes, is one of the most
 important  means of preventing excessive  soil
 erosion at active mine sites. However, the effec-
 tiveness of vegetation in stabilizing the soil will
 be limited unless existing and future site condi-
 tions  are adequately assessed in the selection
 of plant material and proper establishment prac-
 tices are followed.
 Plant Selection

    Each plant species has its own growth charac-
 teristics that determine its value in stabilizing
 soil. Grasses and legumes are the most effective
 plant materials for controlling  erosion  in  the
 early stages  of reclamation. However, they are
 short-lived species and are generally planted in
 combination  with trees and shrubs. Trees and
 shrubs are not very effective in controlling ero-
 sion in the early stages because of their initial
 slow development. But, during the middle and
 late  stages of reclamation,  as the grasses and
 legumes  die  off, the trees  and shrubs form a
 protective canopy and provide a necessary build-
 up of surface organic material as a result of the
 leaf litter, which is excellent in controlling sur-
 face  runoff and  erosion. In  addition, trees and
 shrubs are beneficial for screening, wildlife, and
 forestry purposes.
   Grasses. Grasses are particularly well suited
 for stabilizing mine spoil and other  exposed
 areas at a mine. They are highly adaptable to
 various  site  conditions  and  provide a  quick,
 dense, and  lasting ground cover. Furthermore,
 the  dense,  fibrous roots of  grasses securely
 anchor the soil and allow surface water to infil-
 trate more rapidly. Grasses commonly used in
 stabilizing mine  spoil include  tall fescue,  weep-
 ing lovegrass, and redtop. Other grass species
 and their characteristics are given in table IV-4.
   Among grass species, a high degree of adapt-
 ability to various site conditions exists. Species
 are available  for different exposure (sunlight,
 temperature,  and  wind)  conditions, and for
planting during  the  spring,  summer, and fall.
 Some  species are highly tolerant of wet soils,
while others do well on dry, droughty soils.
 Table IV-3.—Maximum permissible velocities in channels
    lined with uniform stands of various grass covers,
                  well maintained3



COVGT




Bermudagrass . . .

Buffalograss ... \
Kentucky bluegrass . . 1
Smooth brome . . . . /
.... i
Blue grama ... 1
Grass mixture ..'...

Lespedeza sericea . . . \
Weeping lovegrass . . . J
Yellow bluestem . . . . (
Kudzu .... /
Alfalfa . . 	 	 I
1
Crabgrass . '. . . /
Common lespedezad . . |
Sudangrassd 	 (



Slope range


Percent
( 0-5
< 5-10
. | Over 10
!'
0-5
• 0-15
Over 10
.
. f bO-5
< K
1 b5-10



cO-5


cO-5
Maximum
permissible
velocity on:
Erosion- Easily
resistant eroded
soils soils
ft/s ft/s
8.0 . 6.0
7 fi EI n
' .U O.U
6.0 4.0

, 7.0 5.0
6.0 4.0
5.0 3.0
5.0 4.0
- 4.0 3.0



3.5 2.5


3.5 ., 2.5
    aUse velocities over 5  ft/s only where good covers and
 proper maintenance can be obtained.
    bDo not use on slopes steeper than 10 percent.
    cUse on slope steeper than 5 percent is not recommended.
     Annuals; used on mild slopes or as temporary protection
 until permanent covers are established.
    Source: Design Charts for Open-Channel Flow, Hydraulic
 Design Series No. 3'  U.S. Department of  Transportation,
 Federal  Highway  Administration,  Washington,  D.C.  Aug.
 1961.
   The ability of many grasses to spread them-
 selves  by  surface  and  underground  runners
 (stolons and rhizomes)  is  another important
 aspect.  Given time and proper  maintenance,
 these  grasses are able to heal minor, breaches
 in the ground cover resulting from erosion, plant
 disease,  and other factors.
   Legumes. Legumes are  commonly  used in
 surface mine areas in combination with various
 grasses. They are important because  of their
 ability to take nitrogen from the air and store it
in their roots. This stored nitrogen can be made
available to nbn-nitrogen-fixing plants, such as
grasses,  and assist in their growth.

-------
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                                             igfifjf
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                                                                    ai-;rk,*f»t«lK?^ies^i
	a «•_-.. '••te;X. * fif. Vs '>'»*'? SiiF^;8"F'"*lti"*l'?*;'fti« •-
. --  '  "',,.  J'11',- |w5b ,»f*t "'j-*A#ii!1 S r^ ii,"i  * S^  -'."i^'.-^Sf&^M
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                           "  "f  «    ::". '";,|'V','Of
               Figure IV-26.  Stone riprap protecting bends in stream.

Figure IV-27. Riprap check dam (grade control structure) placed in a drainageway.
                                       46

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support good stands of Kentucky bluegrass.
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                                                        48

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    Legumes have a large taproot that extends
  deep into the soil and enhances both soil stabili-
  zation and infiltration (fig. IV-7). When legumes
.  are planted, less nitrogen fertilizer is required
  to maintain the ground cover. Nitrogen is usu-
  ally very deficient on most surface mine spoil
  and  is needed to  establish legumes.  Before
  legumes are planted, the seed should be treated
  with the proper inoculant to insure the presence
  of nitrogen-fixing bacteria needed to carry out
  fixation.  Inoculating   bacteria  for particular
  legumes are commercially available.
    Legumes commonly used with  grasses in
  stabilizing mine spils include sericea lespedeza,
  crownvetch, clovers, and birdsfoot trefoil. Other
  legumes that are commonly used for revegeta-
  tion are given in table IV-5.
   Shrubs. Various  shrubs  are available  for
  planting on surface-mined areas. Although they
  are primarily useful as wildlife habitats and for
  esthetic purposes, some species have been devel-
  oped  that can help to stabilize the soil. Bristly
 locust can be  applied  directly with a  hydro-
  seeder. It provides good surface cover and is a
 rapid thicket former on acidic  spoil.  Another
 advantage in using locust is that it is a legume.
 Other commonly used  shrubs include autumn
 olive and amur honeysuckle, in addition to those
 listed in table IV-6.
   Trees. Trees have limited uses as soil stabi-
 lizers during early  periods  of  growth.  Their
 shallow, nonextensive root  system,  as well as
 their  slow and  upright  growth habit,  severely
 limits  their effectiveness  in stabilizing soil.
 Trees should be used in combination with grasses
 and legumes to  provide long-term  protective
 cover.  The grasses  and legumes provide the
 necessary protection in the early years while the
 trees develop their protective canopies and build
 up a  stabilizing  litter  of dead  leaves on the
 ground.
   Once established, trees can provide an effec-
 tive screen as well as a habitat for wildlife. Trees
 also represent a renewable, marketable natural
 resource.                             .  ,
  Selection Criteria. In  selecting plants for
erosion control,  the following criteria should be
considered:
• Their ability  to withstand the erosive and
  traffic  stresses present at the area  being •
  stabilized
• Their adaptability to existing soil conditions
  (pH, moisture, texture, and fertility)
• Their adaptability to climatic condition (sun- ,
  light exposure,  temperature, wind  exposure,
  rainfall) found at the site   -- •  - -
• Their resistance to insect damage and diseases
• Their adaptability to the postmining land use ••
  • Their compatibility with .other plants selected
    for use on the same area
  • Their, ability to propagate (either by seed or
  •  vegetatively) themselves
  • Their maintenance requirements

    To minimize the possibility of failure in estab-
  lishing a plant cover and at the same time reduce
  postestablishment maintenance requirements,
  select plants that are adaptable to the  natural
  conditions found at the site:
    The   characteristics  of  grasses,  legumes,
•> shrubs,  and trees commonly used in revegeta-
" tiori of mine spoils .and other denuded areas at
  mines are summarized in tables IV-4, IV-5, and
  iv-6.                   ; •

  Seedbed Preparation

    Grasses and legumes  used in revegetating
 mined areas are established by direct seeding on
 a properly prepared seedbed (fig. IV.-28). Woody
 plants, such as shrubs and trees, are established "
 by seedling.  However, some species can be di-
 rect  seeded. Whatever technique is used, most
 mine soils  require ameliorative treatments be-
 fore planting. It is  recommended that the topsoil
 to be vegetated be analyzed to determine the
 proper lime and fertilizer requirements. Various
 problems and required treatments  are  as fol-
 lows:

 « Acidity (low pH): Lime and tbpsoiling mate-
   rial should be applied to increase,the pH to
    5.5 if possible.
 • Low fertility: Fertilizers should be added to "
   provide  required  plant nutrients as  deter- .
   mined  by the soil test.
 • High surface temperatures: Black spoil mate- ...
   rials should be covered  to  prevent high,
   seedling-killing temperatures.  -  "           r
 « Excessive rockiness;  Large rocks and boul-
   ders should be removed and buried deeply in
   the pit or used for riprap in waterways.
 «  Droughty soils:  Use drought-tolerant plants, -
   mulches,  fine-grained  topsoiling'; material,
   and organic additions.
 0  Topsoil: The surface or subsurface soil mate-
   rial most suitable for plant growth should be
   used. Selective stockpiling of material may •
  "be required.
 •  Wet soils: Provide good surface drainage and
   plant moisture-tolerant  vegetation. Possibly
   use a rock blanket or long-term mulch mate-
'"-  rial in combination-with vegetation.  -,,
 •  Dense,  poorly permeable soils: Loosen soilby
  •scarification or "tillage. For clayey soils, also
   add lime to loosen soil structure or  cover
  ; with, a more desirable soil.            -;
                                              49,;:

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Table \\J-Q.-Commonly used trees and shrubs
Common name
Shrubs:

Amur honeysuckle

Bristly locust

Autumn-olive

Bicolor lespedeza

Indigo bush

Japanese fleeceflower

Silky dogwood

Tatarian honeysuckle

Trees, conifers:
Virginia pine

Pitch pine

Loblolly pine

Scotch pine

Shortleaf pine

White pine

Austrian pine

Japanese larch

Red pine

Rocky Mountain juniper

Eastern red cedar

Mugho pine

Trees, hardwoods:
Black locust

Bur oak

Cottonwood .

European black alder

Green ash

Hybrid poplar

Red dak •.

European white birch

Sycamore

Scientific name


Lonicera maacki
podocarpa
Ftobinia fertilis

Elaeagnus umbeltata

Lespedeza bicolor

Amorpha fruticosa

Polygonum cuspidatum

Cornus amomum

Lonicera tatarica
sib erica

Pinus virgin/ana

Pinus rigida

Pinus taeda

Pinus sylvestris

Pinus echinata

Pinus strobus

Pinus nigra

Larix leptolepis

Pinus resinosa

Juniperus scopulorum

Juniperus virgin/ana

Pinus mugo mughus


Robinia pseudoacacia

Quercus macrocarpa

Populus deltoides

Alnus glutinosa

Fraxinus pennsylvanica
•--<
Populus spp.

Quercus rubra

Betula pendulata

Platanus occidentalis
•- ' " ' • '.
i Remarks

i • '
Good' for wildlife. Shows more vigor and adaptability as plants mature.
1 '
Extreme vigor. Thicket former. Good erosion control. Rizornatous, 5-7
ft tall. Excellent on flat areas and outslopes.
Nitrogen-fixing nonlegume. Good for wildlife. Excellent fruit crops. Wide
adaptation. Up to 15 ft tall.
Can be established from planting and direct seeding. Ineffective as a ground
cpv|er for erosion control.
Has high survival on acid spoil. Leguminous. Not palatable to livestock.
Thicket former. Slow spreader. 8-12 ft tall.
Grows well on many sites, especially moist areas. Excellent leaf litter and
canbpy protection, :pH range of 3.5 to 7.0.
Grows best on neutral spoil pH. Can withstand pH range of 4.5 to 7.0.
Sorpe value as wildlife food and cover plants. Poor surface protection.
Upright shrub, forms clumps. Does well on well-drained soils. Up to 12 ft
tall Takes 2 years for good cover.

Tolerant of acid spoil. Use for esthetics and where other species will not
survive. Slow development. Good for wildlife.
Deep j-ooted and very acid tolerant. Can survive fire injury. Deer like small
seedlings. Plant in bands or blocks.
Very promising species, rapid early growth. Marketable timber products.
Cap survive pH 4.0 to 7.5. Susceptible to ice and snow damage.
Good for Christmas trees if managed properly. Can be planted on all slopes
and tolerates pH of 4.0 to 7.5.
Some insect problems. Will sprout freely if cut or fire killed when young.
Good marketable timber.
Maybe used for Christmas trees. Has poor initial growth but improves with
time. Plant in bands or blocks.
Can b£ planted on all slopes. Plant in bands or blocks. When planted near
black locust, deer cause browse damage.
Should be planted on unleveled and noncompacted spoil. Provides good
litter.
Sawfly damage in some areas. Plant on all slopes. Light ground
cover.
Has shjown good survival on Kansas spoil materials. Compact growth varie-
tiesfhave from silver to purple colors. -
Tall, narrow growth. Best on dry, sandy soils. Good with black locust. pH
,5.0 to 8.0.
Survives on acid spoil. Develops slowly. Low growing. Good cover for
wildlife.

Can be direct seeded. Wide range of adaptation. Rapid growth; good leaf
litter. Use mixed plantings. Dominant stem clones preferred.
Better survival with seedling transplants than acorns. Light to heavy ground
cover.
A desirable species for large-scale planting. Good cover and rapid growth.
Pure stands should be planted.
Rapid growing. Wide adaptation. Nitrogen fixing, nonlegume. Can survive
pH 3.5 to 7.5. Adapted to all slopes.
Very promising species. Use on all slopes and graded banks with compact
• loarns and clays. Plant in hardwood mixture.
Rapid growth. Good survival at low pH. Marketable timber after 20 years.
Cannot withstand grass competition. Good for screening:
Makes slow initial growth. Good survival, plant on upper and lower slopes
only. Can grow from pH 4.0 to 7.5.
Makes rapid growth on mine spoil. Poor leaf litter and surface cover-
age.
One of the most desirable species for planting. Poor ground cover. Volun-
teer trees grow faster than planted ones. , •
                  51

-------
  Preparation  Practices.  To obtain a rapid
and successful growth of vegetation, the follow;-
ing practices should be followed:

• When required, topsoiling material should be
  spread to a depth of 15 to 30 cm (6 to 12
  inches). The  spoil surface should be-rough-
  ened before the material is applied so that a
  sound bond can be formed.
• Where terrain permits, soil material should be
  worked by discing, harrowing, or other means
  to  break up  large clods and  eliminate any
  surface crusting. Commercial  rock pickers
  are effective  in  removing rock and debris,
  which  often prevent good seedbed prepar^-
   tion. On steep slopes where equipment travel
  is limited and aerial seeding or hydroseeding
  is performed, the surface soil should be pre-
  pared with commercial pick chains, by drag-
  ging a  cleated dozer track or other device
  along the slope, or by running a cleated dozer
  up and down the slope.
• Application rates for lime  and fertilizers
   should be determined from soil tests. Where
   terrain  permits, the lime should be worked
  into the soil to  a depth of about 15 cm (6
  inches) by discing or harrowing. Highly acidic
   soils (pH below 4.0) will require extra lime.
• Seeding should be performed as soon as pos-
  sible  after final  grading or application of
   topsoiling  material.  Surface   soil crusting
  resulting from delays in seeding can result in
  poor seed germination and loss of seed due to
  wind action and surface runoff.
• Mulches should be applied immediately after
  seeding to promote growth and  provide tem-
  porary stabilization. Mulch crimping is an
  effective means of securing  mulching mate-
  rial, especially on steep slopes  and in areas
  where wind is a problem.
  pH and  Liming. The primary factor limiting
plant growth on surface mine  spoil is acidity,
which is often expressed as pH.
  The pH of a soil is a numerical measure of the
acidity (sour) or alkalinity (sweet) of the soil
(fig. IV-29). On a scale of 1.0 to  14.0, acid values
range from 1.0 to 7.0 with 1.0 being the most
acidic and 7.0  being neutral.  Alkaline values
range from 7.0 to 14.0,  with 14.0 being the most
alkaline.
  The acidity of most  surface mine spoil limits
the number of plant species that can be planted.
Some plants, such as weeping lovegrass, can be
planted on spoil with a pH as low as  4.0. How
ever,  other species, such as K-31 tall fescue,
require a pH of no lower than about 5.0 before
good growth can be obtained.  Legumes gener-
ally require a higher pH than grasses.
  Lime is used to correct acidic soil conditions
and enhance the availability of soil nutrients,
such as phosphorus and magnesium.  Some nu-
                                          yef ;#•»"", *s- "_i •"••„ ',,(»' t&i&fy, *?&••*
                                Figure IV-28.  Well-prepared seedbed.
                                              52

-------
              ALKALINITY
                RANGE
              ACIDITY
               RANGE
DEGREE
Strong
Moderate
Mild
Neutral
Slight








. . f
Medium
Strong
Very strong
Extreme




PH
VALUES
8.0
7.0
6.0
5.0
4.0
3.0
                                                                  OPTIMUM
                                                                     RANGE
                                                                        FOR
                                                                      MANY
                                                                     CROPS
                                                                         FEW
                                                                       KINDS
                                                                           OF
                                                                      PLANTS
                                                                      THRIVE
                                     Figure IV-29. pH scale.
                                           T
trients become available  with increased pH,
while other elements, which are toxic to plants
at low pH levels, become unavailable. When
liming acidic spoil, the rates applied should be
based on soil tests. When samples are collected
for laboratory analysis, subsoil (below 15 cm, or
6 inches, in depth) and surface soil (top 15 cm,
or 6 inches) samples should be taken. This will
insure that  sufficient lime will be applied to
counteract current and future acidity.
   Table IV-7 contains the  approximate liming
rates  required to increase  the pH of  various
tested soils to 4.5 to 5.0, 5.0 to 5.5, and 5.5 to
6.O.4 These figures should only be  used as ap-
proximates. Soil samples should be taken and
analyzed for accurate rates.
  When purchasing and applying agricultural
lime to spoil  material, the following factors
should be understood:

• Common agricultural limestone or  ground
  limestone is the most common  liming mate-
  rial for correcting spoil  acidity. Limestone
  may  consist mainly of  calcium carbonate
  (CaCO3), or it may contain both calcium car-
  bonate and magnesium carbonate (MgCO3).
  Limestone that contains about as much mag-
  nesium  carbonate  as calcium  carbonate is
                                            153

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          Table IV-7.—Agricultural lime needed to increase surface mine spoilpH to specified level3'**

Spoil pH test

Less than 3.0 . .
3.0 to 3.5 ....
3.5 to 4.0 ....
4.0 to 4.5 ....
5.0 to 4.5 ....
Tons lime needed per acre to increase pH to
4.5 to 5.0
Stabilization and erosion control
6 to 8 or more
3 to 5 or more
2 to 3
1 to 2

5.0 to 5.5
Medium forage production
8 to 10 or more
5 to 7 or more
3 to 5
2 to 3
1 to 2
5.5 to 6.0
High forage production
10 to 12 or more
7 to 9 or more
5 to 7
3 to 5
1 to 3
  *Rate per acre is based on lime having a neutralization value of 100 and affecting a 15-cm (6-inch) depth.
  bThese figures are only an approximate. Soil samples should be taken and analyzed for accurate rates.
  Source: Guidelines for Reclamation and Revegetation, Surface-Mineral Coal Areas in Southwest Virginia, Virginia Polytechnic
Institute and State University, Extension Division, Feb. 1973.
  called dolomite. Limestone containing lesser
  proportions of magnesium carbonate is called
  calcitic or magnesian limestone. Other liming
  materials include quicklime, hydrated lime,
  chalk, marl,  and fly ash. Rock phosphate is
  high  in calcium and has  some  neutralizing
  effect on acidic spoil in addition to providing
  phosphorus.
  The total capacity of lime to correct acidity,
  or the neutralizing value, is measured by the
  calcium carbonate equivalent.
  The size of the particles of the liming material
  is usually the best guide to the rate at which
  soil acidity can be corrected. The smaller the
  particles are, the faster the lime can correct
  acidity. The coarser the lime particles,  the
  less reactive the material.
  The ideal time for lime application is 6 months
  prior to seeding. When this is not possible,
  the finest ground limestone  should be pur-
  chased and thoroughly mixed with the soil as
  far in advance of seeding as possible.
  Lime should be applied  immediately after
  grading, regardless of season,  and worked
  into the spoil to a depth of 15 cm (6 inches).
  On extremely acidic spoil, lime should be
  applied to a depth  of 25  to 30 cm (8 to 12
  inches). In this event, additional lime will be
  required.
  Lime can be  applied by truck, tractor-drawn
  spreaders,  and  by  hand  broadcasting.   On
  steep outslopes, lime can be applied by rear-
  mounted blowers attached to liming trucks.
 •  Maintenance liming may be required in the
   third or fourth season following the initial
   application,  based  on  soil-testing  recom-
   mendations.

   Fertilizing. Most surface mine spoil is  defi-
 cient in plant nutrients such as nitrogen, phos-
 phorus, and sometimes potassium, which are
 needed for plant  establishment and  sustained
 growth. Prior to  the use of any fertilizer,  soil
 samples should be taken and analyzed by State
 or commercial soil-testing  laboratories experi-
 enced in mining  soils and spoils.  Fertilizers
 should be  selected based on the results and on
 the recommendations of the lab.
   Fertilizers are labeled according to their nitro-
 gen  (N), phosphate (P2O5), and  potash (K2O)
 content. These  values  are  given in percent or
 pounds per 100 pounds of fertilizer. This is called
 the  fertilizer  grade.  For  example,  the grade
 5-10-10 contains 5 percent  N, 10 percent P2O5,
 and  10 percent K2O. Likewise, an 0-20-20 fertil-
 izer contains no N, 20 percent P2O5, and 20 per-
cent K2O.
   When a  soil test recommendation calls for 25
pounds of N, 50 pounds of P2O5, and 50 pounds
 of K2O per acre,  a fertilizer with a 1-2-2 ratio
 (twice as much P2O5 or K2O as  N) is needed.
This ratio  can be  provided  by using a 5-10-10-,
 6-12-12-, 8-16-16-, or  10-20-20-grade  fertilizer.
 If a 5-10-10 grade is chosen to supply 25 pounds
of N, 50 pounds of P2O5, and 50 pounds of K2O,
the first number of the grade (5) is divided into
                                               54

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   the N recommendation (25) and the result mul-
   tiplied by 100, as shown below, to arrive at th'e
   amount of fertilizer required per acre.         j

        25/5 = 5 x 100 =500 Ib/acre of 5-10-10     |
                       to supply 25 Ib N,        j
                       501bP2O5,and501bK2O   !
                                               I
      Higher  analysis,  or "straight"  fertilizer^,
   contain only one of the nutrients. Examples arje
   concentrated  super  phosphate,   0-46-0,  and
   ammonium nitrate, 33.5-0-0. These high-analysijs
   fertilizers  can be  combined  to  provide some
   advantages over the use of regular mixed fer-
   tilizers because:                             j

   •  They  are generally more  economical  than
      mixed fertilizers.
   •  There is less material to handle.
   •  Extra amounts of fertilizers are avoided.     j
   •  Seed damage due to unneeded potash (K2O) is
      avoided. (This damage can occur with mixed
      fertilizers such as 10-10-10.)                I

      In addition to commercial synthetic fertil-
   izers, the organic materials listed in the follow(-
   ing table have some  fertilizing value  and are
   available in some areas:5                  .
Organic
fertilizer
Cattle manure 	
Poultry manure .......

i
Pounds per ton |
N
10
20
P>05
5
16
K2G)
— o-oo —
r—
     In  some  areas, sewage sludge and fly ash
::•  have been used for  fertilizing spoil; howeverl
   technical assistance  should be obtained before
   using the material. The U.S. Soil Conservation
 ,  Service (SCS) is often a good source of informal
   tion for local conditions.
    " Fertilizers should be applied at the time  of
•""'seeding, when conditions will be favorable for
 •';/germination. When seed is planted in sandy soil
'(r in late fall  and remains dormant,.during the
 1  winter,  fertilizer  application  should be  post-1
   boned until early spring when the seed begins  to
.-;-. germinate. Otherwise,  fertilizers can leach out)
,\.of the soil during the winter and make refertil-*
 ,sization necessary. On the other hand, heavy,
/•clay soils that are wet  in, the spring can be fer-j
,   .tilized in the late fall even though  the seed will,
 •"remain dormant until spring. Clay  soil will hold;
 : 'the fertilizer and -prevent it from leaching, espe-j
 ucially  if winter temperatures are low. Mainte-j
  nance applications of fertilizers may be required
  in the third year or later on soil-testing recom-
  mendations.  Methods  of  applying  fertilizers
  include hand, hydroseeder, truck, and pull-type
  spreaders.
     Planting. Methods of planting vegetation at
  surface mining sites vary depending on topog-
  raphy, type of vegetation, stoniness of soil sur-
  face, and equipment availability. Currently used
  methods of establishing vegetation  and their
  specific suitability are:

  • Hydroseeders are very useful for applying
     seed, fertilizer, and mulch to steep, outslopes
     and  other areas where equipment  accessi-
     bility is limited (fig. IV-30).
  • Aircraft  are  especially  useful for  broadcast
     seeding  on large areas,  inaccessible  areas
     such as orphan mined lands, and during thaw-
    ing and freezing periods.
  • Cyclone seeders are well suited for broadcast-
    ing seed on benches and level areas. Germina-
    tion can be increased by limiting equipment
    travel over seeded areas.
  • Grass or grain drills are limited to rolling or
    level terrain that is relatively free of stones.
    The Rangeland drill is sturdier than conven-
    tional drills and provides better and longer
    performance on strip mine spoil.
  • Rear-mounted blowers  can be  attached to
    lime trucks to spread both seed and fertilizer
    on steep  outslopes  and other  inaccessible
    areas.'
  • Hand planting generally is  used when  trees
    and shrubs are planted. The method  is time
    consuming and therefore costly.

    Mulching. Mulching is required to protect
 the newly seeded area from, soil erosion during
 and immediately  following  the germination.
 period. In addition, mulching provides a better
 environment for germination and plant develop-
 ment by conserving soil moisture, moderating
 soil temperature; and,  in  the  case of organic
 mulches, providing nutrients to the soil.
    Recommended practices to be considered in
 the mulching of seedbeds are:

 •  Mulching material should be applied at the
    recommended rates (sec. II, vol. II). The ma-
    terial should be spread as evenly as possible
;•''" over the entire site. A comparison of straw
    mulching rates and Surface coverage is given
    in figure IV-31.
 •  Organic mulches, such as straw, hay, wood-
    chips, and wood fiber, should be given prefer-
    erice over inorganic mulches, since they pro-
    vide needed micro-organisms, seeds, organic
:   matter,"ahd'nutrients to the soil:
*J?» {-.•-:«--'ii;;.-"•".) ...'-i'>,x:»'!--  ',if , i. •;> f>•>!' ••;!.<:-
                                                 55

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            	'.:,: v t, •>.ll:: *".<'.") v'K'i	I. V* '*W !*i|S l:; ^ - *' ^^-ifel J. ';^ .>v'. -.
                                                                                •«s,u» ,-..»'•,.

                                                                               •«a»pi9!W(	rf-1	F jf*3
                                                                              ,>«!»••.';,:!»i* IS -s i^ f';Wl-
                                                                                     C's-jwr^a.j
                Figure IV-30.  Hydroseeding a graded and properly roughened mined area.
•  Straw and hay mulches should be tacked to
   prevent their removal by wind. Crimping is
   the preferred method of securing the mulch
   material. Asphalt and  emulsified chemical
   tack  materials are also  suited for securing
   straw and hay mulch.
•  Highly acidic  spoil areas should be given a
   heavier mulch application. Fiber glass, stone,
   and  other  nonbiodegradable  mulches  will
   provide long-term stabilization of these prob-
   lem areas,

Information Sources

   In addition to assistance from State reclama-
tion departments, various forms  of assistance
are available to coal mine operators and their
representatives  from local, State,  and Federal
agencies.
   County agricultural extension agents can be
contacted for  information concerning soil sam-
pling, soil  testing, revegetation,  and other
matters related  to  agriculture.  Local agents
may be contacted through the offices of State
extension service directors listed in section IV,
volume  II.
   The SCS alsp has regional and county offices
that can provide valuable assistance in planning
revegetation and other erosion and sediment
control  efforts. Local SCS representatives may
 be contacted through the State conservation-
 ists' offices listed in section IV, volume II.

              MAINTENANCE

   Maintenance of erosion control  practices is
 an extremely important requirement in achiev-
 ing  effective control.  Roadways  and  water-
 handling structures require considerable main-
 tenance attention during mining. Also, attention
 must be given to revegetated areas in order to
 insure  that   long-term  soil  stabilization  is
 achieved.

 Runoff Control Practices

   All water-handling structures must  be in-
 spected after every major storm to be sure that
 no breaches have occurred. Sediment buildup in
 diversion structures, such as dikes and ditches,
 must also  be checked.  Outlet disposal areas
 require frequent inspection to insure that no
 erosion is occurring.  Erosion damages require
 prompt repair to prevent further soil loss and to
 protect other areas of the site. Measures should
 also  be taken to  insure  that  similar damage
does not occur in the future.
   Sediment and other soil debris removed from
ditches and  other water-handling  structures
should be disposed of in the mine in a manner
                                              56

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that will prevent the sediment from being car-
ried back into the waterways at the mine.
Vegetative Stabilization Practices

  When revegetating with grasses and legumes,
top dressing with nitrogen,  phosphorus, and
potassium fertilizers is required on a periodic
basis to keep vegetation healthy and provide
long-term erosion control. Too often a stand of
vegetation is allowed to deteriorate and become
ineffective because it is nutritionally starved.
Fertilizer will help keep a dense stand and pro-
vide for the growth of desirable  plants. Soil
samples should be  taken from reclaimed areas
and  additional  lime and fertilizer  added  as
needed.
  Areas where  failures have been experienced
in the establishment of vegetative protection


                 ' av'^. .•&*£'*t&*&&t

                                                                   iM^fe^Ssrll F - .5
         •-fe^SssSsl&sfc^*'          iisss

                 * 'W {& -f we• ^*yA * # ~^5 i.-"*"-X»«t * * -s' i^**  t^








                                •
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must be promptly treated. If the failure is due to
rilling or gully formation, temporary structural
practices, such as flexible downdrains and sec-
tion slope drains (sec. I, vol. II), can be utilized
while arrangements for permanent control  are
made. The reestablishment of permanent vege-
tative cover should be the ultimate goal.  How-
ever, changed site conditions may require  the
installation  of some sort of permanent struc-
tural control, such as level spreaders or diver-
sion (sec. I, vol. II). 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.

IMonvegetative Stabilization Practices

   Roadbeds should be kept in good repair to
prevent rutting and subsequent subbase satura-
tion and erosion.  The roadway  needs to be
graded periodically to maintain surface drainage
and keep the surfacing material evenly distrib-
uted over the roadbed. The roadbed is usually
maintained by grading smoothly with a blade.
Shaping should be done in  the spring after the
road has lost its heavy moisture, but before it
becomes hard and dry. Routine smoothing dur-
ing the summer should be done after a rain has
moistened the road but not made it  slippery.
In grading the road, considerable care must be
taken to prevent soil from being pushed into the
ditch, and to prevent damage to vegetation on
the safety berm.
  During dry periods, periodic watering of the
roadway may be required to prevent the dust
from damaging nearby vegetation and entering
the ditch. Once in the ditch, the dust can be
easily transported to lower lying natural water-
ways.
  Channel  stabilization  structures, such  as
revetments, and check  dams found  in ditches,
diversions, and streams must also be frequently
inspected for damage. Repairs must be prompt
to prevent further costly damage, and measures
should be taken to prevent a reoccurrence of the
problem.
               REFERENCES

   1H. D. Buckman and N. C. Brady, The Nature
and Properties of Soil, 7th ed., New York, Mac-
millan Company, 1972.
   2U.S. Department of Agriculture, Soil Survey
Staff, Soil Survey Manual, USDA  Handbook
No. 18, Aug. 1951.
   3W. H. Wischmeier and J. U.  Mannering,
"Relation of Soil Properties to Its Erodibility,"
Soil  Science Society of America, Proceedings,
vol. 33, 1969.
   ^Guidelines for  Reclamation  and Revegeta-
tion, Surface-Mined  Coal  Areas 'in  Southwest
Virginia,  Virginia Polytechnic  Institute and
State University, Extension Division, Feb. 1973.
   5J. A. Silphen, Bulletin  262, Ohio State Uni-
versity.
                                             ,58

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                                         Section V

                                 SEGMENT   CONTROL
   Many coal-producing  States  prohibit the|
discharge of'high concentrations of sediment
into their streams. Surface coal mining involved
massive earth-moving operations that subject,
large  areas  of unstabilized  soil to  accelerated
erosion. Guidelines to reduce erosion have been
presented in the preceding section. To supple-j
ment  these erosion  control  practices, and to
provide a secondary line of defense against any!
possible off site sediment pollution, a numbeij
of sediment control practices can be used. The
objective of these practices is to filter, or settle
out, any waterborne sediment  sufficiently to
meet  appropriate State  or Federal effluent
limitations.  At the same time these structure^
delay and reduce  peak flows in the streams,!
thereby reducing the potential for stream ero-j
sion.
                                            I
      SEDIMENT TRANSPORT AND      i
               DEPOSITION               |
                                            I
  Sediment is  a product of erosion. The com-|
bined processes of soil detachment, dispersion,!
transportation,  and,  finally,  deposition are'
referred to as sedimentation.  The first line of
defense against sedimentation is an effectively:
designed erosion control program. However,  it
must be stressed that even with the use of the,
most effective  erosion control techniques, soil
loss cannot be  totally eliminated. The need foij
containment  of sediment,  therefore, is equally
important. This section addresses those conj
tainment measures.                          |
  Surface runoff is the prime mover of detached
soil particles. The sediment load transported by
the  runoff consists  of wash  load, suspended
sediment  load, and  bed load. The wash load
consists of very fine, or colloidal (silt- and clay]
sized) particles, which settle  very slowly even
in still water. The suspended  sediment is com]
posed of inorganic soil particles  (fine sand, siltj
and clay)  and organic  particles carried anc|
supported  by the  water itself  Bed load sedii
ment refers to the coarser particles of soil, which
move by rolling, sliding, or bouncing along the
streambed. The capacity of the channel to trans-
port material at any location decreases as the
amount of sediment  being  carried increases,
regardless of the type of transport taking place.

         FACTORS INFLUENCING
             SEDIMENTATION

   Sediment transportation and  deposition  is
influenced by:

*  The flow characteristics of the water
•  The nature of the particles transported

   Flow characteristics are determined by the
velocity and turbulence  of the moving water.
As velocity and turbulence increase,  the water
is able to transport more sediment.  Conversely,
as velocity and turbulence decrease,  the water
has  less potential for transporting  sediment,
and deposition of soil particles occurs.
   The nature of the particles being  transported
refers to their size, shape, and density. Smaller
and lighter particles, such as fine sand, silt, and
clay, are more easily transported by water than
coarser particles; the coarser and heavier  par-
ticles are more easily deposited.

  SEDIMENT CONTAINMENT STRATEC5Y

   In developing a sediment containment strat-
egy for a particular mine site, or a portion  of
that site,  there are a few basic concepts  that
must be considered, if  the greatest possible
degree of control is to be achieved. First among
these is the concept of "at-source" control. This
means that every effort should be made  to
control the sediment at, or as near to, its source
as possible (fig. V-l). It is too often  the practice
to attempt to  control the sediment from the
entire area being disturbed by building one  or
more large sediment basins  offsite and  in the
major  drainageways (fig. V-2). This approach
requires that a much  larger drainage area be
controlled, as well as the construction, cleaning,
and possibly, the postmining removal of larger
structures. From a sediment control standpoint,
                                              59

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                                                    .
                                  ,. ,*   jjp^nni  n-jn,lt.,jrpiliti,|.ul.*r.ai--,i,,r;-;||l;ll.,"1 3,,,, ,IF f '» . '
                                , '.- Igr- , • ,;•• •A-^L'MjSsSS^f ^
                           Figure V-1. Trapping sediment on the bench near its source.
 j»p»ii	ii	j	"'i
iidlBlitf""!' „	 	;	:ii', L3" 	••
                           Figure V-2. Perimeter sediment basin at a surface coal mine.
                                                          60

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and for other environmental reasons, it is morei
desirable to segregate the sediment-laden wa-j
ters from the rest of the surface flow.            j
  Another important concept is identification!
and control of all major sources  of sediment. |
The major sources of sediment from surface)
mine operations are generally access roads andj
spoil areas. As shown in table II-2, for an equal|
area of disturbance, sediment yield from haul
roads can be twice the yield from spoil banks,
and 30 times as high as the yield from the entire |
mine—a fact  that  is often ignored. A  single
basin is built in the stream valley to  control the
entire mine site. Portions of the haul road, how- i
ever,  often drain  into  different  watersheds ;j
consequently, some sediment goes  completely j
uncontrolled. The sediment control plan should |
clearly identify all major sediment source areas>
at the mine, and show how the surface  drainage j
from each area is to be controlled.              j
  A third concept, upon which  all sediment i
control practices are  based,  is  runoff control.)
There can be very little control over the nature \
of the particles  transported.  It  is usually j
feasible, however, to control the velocity of the!
water and the associated turbulence. A decrease
in velocity and turbulence will reduce the ability
of the water to transport sediment, and the
sediment will settle out.
  Reduction in  slope steepness and/or length,
roughening  of  slopes,  spreading rather than
concentrating flow,  dissipating flow  energy,
and detaining flow are all means of slowing the
flow of surface  runoff and, thus, reducing its
ability to transport detached soil particles (fig.
V-3). Slowing also reduces the ability of the run-
off to detach other soil particles.
           TYPES OF CONTROL

Vegetative Buffers
  Both natural and installed vegetative buffers
are used to detain, absorb, and filter overland
runoff,  particularly sheet flow, and thus trap
sediment.
  Natural Vegetative Buffers. This practice
involves the preservation and protection of a
strip  of natural vegetation downslope of the
              Figure V-3. Slope roughening and flattening to trap sediment near its source.
                                              61

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area disturbed by mining (fig. V-4). Where the
ground slope is not too steep, a band of thick
vegetation, whether grass or woody plants with
accompanying ground litter, is an effective and
economic means of trapping sediment washed
from perimeter spoil slopes or haul road out-
slopes.
  Installed Vegetative  Buffers. Where the
existing vegetation will not form a satisfactory
buffer, or where  an open drainageway is con-
structed, timely establishment of a vegetative
buffer will help trap sediments (fig. V-5). Staging
grading operations to provide a vegetated area
between  critical features, such as a drainage-
way, and higher elevated areas being reclaimed
is  the recommended procedure for installing a
vegetative buffer. The surface of the buffer area
should be roughened and planted to a quick-
growing, robust grass. Flattening the slope in
the buffer area will also help slow the runoff and
trap sediment.


Sediment Traps

   Sediment traps are small, temporary struc-
tures used at various points within, and at the
     • "';	r:<	:»^.3fe»4!fii«£^ •';	sfr.r;.
                       Figure V-4. Natural vegetative buffer below a haul road.
               Figure V-5. Vegetative buffer strip below a spoil bank trapping sediment.
                                              62

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wSf^SA-^^l^1*^*^©^ «S"tttii.''':'-„ !>.y*/'-i5-ii%-jr-..*•.'••-• • • -•;#r:f.J>ft^|!,fa^«Afc.

;'ii-S.»w»mi-iKif               -k.?, ^fe&lsasu-iii. -i:*-kJLsfc..>-ifcSt,**M*im^tfc&#«* «.
                           Figure V-7.  Stone ch!eck dam trapping sediment.

periphery of,  disturbed  areas to detain runoffj
for a short period of time and trap heavier sedi-1
ment particles (fig. V-6). Various types of sedi-
ment traps used include sandbags and  straw
bales,  stone check  dams,  log-and-pole  struc-j
tures,  excavated ditches,  and small, pits (fig.
V-7).  In fact,  any sufficiently large depression
in the surface will act as a trap. Depressions or|
undulations, particularly in the pit area, are)
                                                recommended since they will detain the runoff
                                                and help to  settle out some  of the  suspended
                                                sediment. See section I, volume II,  for design
                                                and construction considerations.
                                                  Sandbags and Straw Bales. These devices
                                                are very easy and economical to construct. They
                                                need a  limited amount of equipment for their
                                                construction, and therefore create less disturb-
                                                ance of the area in which they are constructed.
                                             63

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   Sandbag-barrier  sediment  traps  are con-
structed of bags filled with sand or crushed rock
that are stacked in an interlocking manner (fig.
V-8). Straw bale sediment traps are constructed
of bales of hay or straw stacked as  shown in
figure V-9. Tying the bales with wire  and stak-
ing them to the ground provides  additional
stability. Undercutting is the major cause of
failure of these barriers. This can be prevented
by setting the sandbags or straw bales 4 to 6
inches in a trench and compacting  excavated
soil along the upstream side.
                      Sandbag barrier
                    Undercutting occurs
                         when sandbags
                            lie on surface
                              of channel
                                                 Compacted soil
                                                 prevents piping
                                                 underneath
                                                 sandbags
                                 Figure V-8. Sandbag barrier.
                                Figure V-9. Straw bale barrier.
                                          64

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   Log-and-Pole Structures. A drawing of a
log-and-pole structure is shown in figure V-10.
These structures are built across waterways. The
structure is built from the timber that is gener-
ally  available at the site.  Log-and-pole struc-
tures serve two purposes. First, they retard the
flow of runoff and catch some of the sediment
load. Second,  they  delay and reduce the  peak
flow in the stream, thereby reducing the poten-
tial  for stream erosion. The effectiveness of
these structures can  be increased further  by
building several structures at regular intervals
along the drainageway.

Sediment Basins

   State-of-the-Art. Sediment  basins  are the
most effective structures for trapping sediment.
They are generally  used in large earth-moving
operations where heavy concentrations of both
runoff  and sediment are anticipated (figs. V-ll
and V-12).  The conventional method of control-
ling  sediment  that reaches the periphery of the
mining operations is through the construction
of a sediment retention basin at a point that
intercepts the surface runoff before it leaves the
mining site. There  are  two types of sediment
ponds: the dry basin and the wet basin. The dry
basin is generally used  to trap sediment in an
offstream location, and,  therefore, is preferable.
The wet basin is used when it becomes necessary
to dam permanent streams in order to trap sedi-
ment.
  Design standards and construction criteria
for sediment basins vary from State to State,
although  most State  standards are adapted
from those developed by the Soil Conservation
Service'(SCS). To this date, only two States in
the region covered in this manual have actually
modified the basin design to fit the surface min-
ing industry.1-2 Under the SCS approach, sedi-
ment basins are usually not designed to achieve
any set effluent  water, quality criterion or to
remove any given percentage of trie sediment in
the inflow. Rather, the size of the basin is usu-
ally determined by utilizing a rule of thumb on
the volume of the basin required based on the
area of land disturbed. For example, the State
of West Virginia, based oh studies by the U.S.
Forest Service and SCS, requires that the sedi-
ment  basin pool  have  a minimum capacity to
store 381  cubic meters per  hectare (0.125 acre-
feet per acre) of disturbed area in the drainage
area.1
  The SCS  sediment  basin design approach
does  not  provide the designer  with  enough
information to insure  that State, and  Federal
water quality criteria are met. A recent study of
the effectiveness of sedimentation basins de-
signed under this method revealed that during
                               Figure V-10. Log-and-pole structure.
                                              65

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 ^l:   %
                    ^^^^^g^i^5^(P^
                            Figure V-11. Sediment basin.
                                                            -'*-- -• *•--  •
Si*/
                   Figure V-12. Sediment basin functioning during a storm.
                                     66

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 a storm the majority of these basins do not meet
 the proposed Federal criteria (table V-l ).3 Clearly
 a more rigorous and complete design procedure
 is needed. An alternative approach derived from
 the design process for settling tanks used in
 wastewater treatment facilities is provided.
   Design consideration.  Designing a sediment
 pond based on the removal of a  certain size
 particle or percentage of suspended sediment
 requires  more design  data than the  SCS  ap-
 proach. Many of the variables that need to  be
 quantified for input to the design are not nor-
 mally measured during the preliminary  design
 or site investigations. However, these  data can
 be  obtained easily during the  site  exploration
 without much additional effort. The following
 factors must be known or assumed before  an
 analysis can be made:4

 • Design outflow rate (design stormflow)
 • Anticipated grain-size distribution of the in-
  coming sediment
 • Expected suspended solids concentration in
  the inflow
 • Specific gravity of the incoming solids
 •  Anticipated pond water temperature

   Solids removal. The sediment basin can be
 designed to achieve  a certain  percentage re-
 moval of the  suspended material or to settle
 out a minimum-size particle. These two param-
 eters are plotted against each other on a grain-
 size distribution  curve. Or, the basin can be
 sized to  meet a given effluent solids concentra-
 tion.  These parameters are related by the fol-
 lowing formula:
   R (% solids removed) = < 1 -
                               106
>100
                                   -1
where Cj = solids concentration of influent, mg/1
      c2 = solids concentration of effluent, mg/1
This  formula, which was originally derived
from  a simple mass balance for a conventional
dredged-material-containment basin, is useful in
evaluating the efficiency of the sediment basin.4
                      Table V-1 .-Results of pond sampling during rainfall conditions
Pond
number
1 ....
2 .....
3 	
4 	
5 	
6 	
7 	
8 	
9 	

Flow
average/range
(m3/s)
0.021
.028
.149
.133
.060
.042
.012-.093
.013
.056-.110
Computed
detention
time
(h)
31.9
7.8
4.4
5.2
325.0
20.8-2.7
184.4
5.7
Sampling
period
(h)
2.0
2.0
4.0
4.0
5.0
26.0
16.0
5.5
7.0
Number'
of
samples
8
:. s
8
16
9
8
9
8
10
Average suspended
solids concentration
(mg/l)
Influent
474
239
21,970
9,643
668
868
765
363
412
Effluent
196
17
11,539
6,198
275
35
66
28
193
Actual,
removal
efficiency
(percent)
58.8
92.8
48.0
36.4
58.8
95.9
91.3
92.3
53.1
Theoretical
removal
efficiency
'(percent)
95
88
83
84
91
99
83-67
97
99
  Source: D. V. Kathuria, M. A. Nawrocki, and B. C. Becker, Effectiveness of Surface Mine Sedimentation Ponds prepared by
Hutman Associates, Columbia, Md., for the U.S. Environmental Protection Agency, Office of Research and Development Cincinnati
Ohio, Contract No. 68-03-2139.                        !                                               '

                                               I
                                              67

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   The removal of solids by settling is basically
 a function of the overflow rate and the surface
 area of the basin. Depth of the basin and deten-
 tion time are not primary design parameters,
 but they can affect the design and thus are sec-
 ondary considerations. An initial approximation
 of the solids removal capabilities of a conven-
 tional basin  can be made by  assuming theo-
 retically  ideal  settling conditions. For  the
 theoretically ideal case, the size of the particles
 that will be retained will be determined by the
 overflow velocity and the critical settling veloc-
 ity of the particles. The basic ideal relationship
 can be expressed in general terms below:4
   Required settling area  =
 Overflow rate
Critical settling
velocity of the
smallest particle
to be retained
 In the design of sediment ponds to settle a cer-
 tain size particle, the ratio of the pond outflow
 to the surface area of the pond, Qo/A, is termed
 the overflow velocity Vo. Thus:

                  Vo = Qo/A

 Based on the above relationship, it can be shown
 that if the critical settling velocity of any  size
 particle  is greater than the overflow velocity,
 that particle and all larger  than it will  settle
 out. Increasing the area of the pond, therefore,
 would decrease the  overflow velocity.  This
 means that  a smaller particle size could be
 settled out.
   Factors affecting ideal settling. In any sedi-
 ment  pond,  it is unlikely  that  purely ideal
 settling conditions will be met. Factors that dis-
 turb the smooth settling and thus alter the pond
 area required as calculated using ideal settling
 theory include:
   Short  circuiting
   Bottom scour
   Turbulence
   Nonuniform deposition of materials
   Entrance and exit effects
   Shape of the suspended particles
   Specific gravity and velocity of the suspend-
   ing liquid

 In most  cases, the effects of the above factors
would  be to increase  the pond surface area re-
 quired over that  calculated by ideal settling
theory. In usual design practice the surface area
calculated by ideal settling theory is multiplied
by a factor of 1.2 to account for nonideal settling
factors.4
   A complete description of the design proce-
 dure and a detailed design example are provided
 in section I of volume II in the design and con-
 struction specifications  for  sediment basins.
   Methods for improving  pond efficiency.  A
 number of innovative techniques have recently
 been developed that can help increase the pond
 efficiency.6

 • Baffles can be located within the pond  to
   increase the detention time and also, if prop-
   erly placed, provide for utilization of the full
   area of the pond.
 • Partitioning the pond into a number of cham-
   bers and then  introducing and overflowing
   water from particular chambers  along the
   entire width  of the sediment pond can also
   improve its performance.
 • Dye tests  on experimental sediment ponds
   have shown that maximum efficiency can be
   expected from a sediment pond when the
   length-to-width ratio is maintained at about
   5tol.
 • Construction of an energy dissipator at the
   pond entrance can produce a reduction in the
   inflow velocity and  consequent deposition
   of sediment before it reaches the pond.
 • Modifying  the inflow to  the sediment basin
   so that the flow enters along as much of the
   entire width  of the basin as possible is an-
   other flow modification  technique that has
   proved effective.
 • Wrapping  a  plastic  filter cloth  around a
   standard perforated riser  can  increase the
   retention of fine-grained  material. However,
   the filter cloth  will eventually plug with the
   fine-grained sediment.
 • A  siphon arrangement in a nonperforated
   riser pipe is also effective in improving the
   sediment pond efficiency.
 0 Use of a very wide overflow wier instead of a
   standard riser pipe reduces the outflow veloc-
   ity and thus increases the removal efficiency
   of the pond.
 • Two or more ponds used  in series instead  of
   one larger basin covering the same area have
   been shown to increase the removal efficiency.
   The multiple-basin concept equates to the use
   of  a  compartmentalized,  larger  sediment
   basin. Thus, higher removal efficiencies can
   be expected  from both  multiple sediment
   basins  and  a   compartmentalized, larger
   basin.

   Chemical Treatment. Generally, the surface
runoff from  the mining  area is  pumped,  or
diverted, into  settling basins where natural
gravitational settling  is used to  remove  the
suspended  solids.  The removal  efficiency of
                                              68

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suspended solids depends on the surface area
of the basin and on the detention time. If the
inflow of the settling basin has a high percent-
age  of fine-grained  (silt  and clay)  sediments,
there may not be adequate land area available
to construct a settling basin of the size required
to obtain the desired water quality. Since fine
silts and clays carry a negative electric charge,
they repel each other, and stay in suspension
for long periods of time, thereby producing a
turbid effluent.  In these cases, chemical treat-
ment  is necessary  to  affect the  negatively
charged colloidal particles, causing them to be-
come attracted  to each other and form larger
masses of particles that settle out.
  Types of Coagulants. The addition of coag-
ulants causes fine-grained particles to agglome-
rate, and thereby exhibit the  settling  charac-
teristics of coarser sized particles. The chemical
coagulants normally used are classified into the
following three types:

• Metal salts
  — aluminum sulf ate
  — ferrous sulfate
  — ferric chloride
• Metal hydroxides
  — aluminum hydroxide
  — calcium hydroxide
 •  Synthetic polymers or polyectrolytes
   — anionic
   — cationic
   — nonionic

   Selection of the type  of coagulant  and re-
'quired  dosage is an important factor  in  the
 design  of  a chemical treatment  system, and
 depends upon the characteristics of the specific
 material to be removed.  There is no  accurate
 theoretical method or  rule for selection of a
 coagulant  and its  dosage.  However,  a rough
 estimate of the  amount  of coagulant can be
 made by a standard jar test, or by measurement
 of the suspended particles. The optimum dosage
 for best results will be adjusted in the field.


              MAINTENANCE

   All sediment containment measures require
 adequate and timely maintenance throughout
 their design  lifespan  to perform  efficiently
 (fig. V-13).  If they are built in an area where
 accessibility is poor, they are often ignored and
 forgotten.  They should be located in an area
 where they are readily seen, and adequate acces-
 sibility  should be provided for the maintenance
 equipment  to perform emergency and  routine
  n  VJ^-^    ~»i>»     n, . .•*      f
  R^?ip:
                                 Figure V-13. Basin inspection.

-------
                                      •" - - "*•'. • ** „,. j-T" v-C* ''*y'*:ji*;y j
                        •«*J^
                                         -   .   •r'^^.'.Cf"^^'*'-'-'^-^^^:y?lf^S^>tv^!sli'^fif-' ' !%«Si?fr*v|L- •*£.;-'
                                                                            "*£•• .'.:.': ' ' T* .v'^'^^vV4 ^','- •
                                                                            •^'•'s-.tytftfy'-'.* .-;.'..•>(.;•"
                           Figure V-14. Well-built and -maintained basin.
repairs.  Responsibility for maintenance  must
be formally assigned  to an individual who is
knowledgeable  of  maintenance requirements
and also has access to  equipment and materials
required for this purpose (fig. V-14).
   All sediment containment structures require
inspection after high-intensity  or major rain-
storms.  Corrective  decisions made  onsite  at
this time can reduce  sediment damages and
operating costs in  the long run.  Most of the
at-source sediment control measures cannot sur-
vive if  they are subjected to foot  or vehicle
traffic.  In areas where the measures are in-
stalled,  the prohibition of traffic must be main-
tained.

Sediment Removal

   The most important  maintenance  problem
associated with sediment containment basins is
the removal  of accumulated  sediment.  Re-
search has  shown  that  the highest  sediment
yields are usually  observed  during  the first
6-month period after  mining. Filling of sedi-
ments in the basin reduces its capacity to retain
runoff long enough for  sediment  to be deposited
before it is  carried downstream. Many States
have established criteria for sediment removal
from  the basin. A  rule of thumb that can be
used is to clean out a basin when it has reached
50 percent of its sediment  storage capacity, or
6 months after the mining operation was started,
 whichever comes first. In the design for storage
 capacity of a sediment basin, provisions should
 be made to accumulate enough sediment to per-
 mit the pond to function for a reasonable period
' between cleanings.
   For small sediment traps used near the min-
 ing activity,  cleaning is generally best accom-
 plished by dragline and truck transport, since
 this  equipment is readily available (fig. V-15).
 Removed material  can be  stockpiled directly
 on the banks,  and allowed to dewater before
 being hauled away, or it  can be buried in the
 mine pit.
   For large  containment  basins  that cannot
 be cleaned by draglines  operating  from  the
 banks,  the  cleaning  becomes more  difficult.
 In such cases, the  services of professionals
 experienced in  the handling and disposition of
 sediment should be retained.

 Sediment Disposal

   Sediment disposal is an integral part of the
 sediment removal program from a containment
 basin.  Indiscriminate piling  or dumping of
 removed material is more likely to allow sedi-
 ment to reenter the  surface drainage system
 dur-ing successive storms,  and thus become a
 pollutant again. The'sediment removal opera-
 tion must also consider the stable disposition of
 the material  removed from the basin.  Where
 disposal  of a small quantity of sediment is
                                             70

-------
involved, it can be disposed of behind a protec-
tive berin or grass filter strip, or buried in the
mine  pit. For  larger quantities  of  sediment,
special provisions should be made either to bury
it in an area designated for this purpose, or to
stockpile, dewater, and vegetate it properly.
     POSTMIIMING CONSIDERATIONS

   Sediment containment structures should be
designed to be temporary structures for trap-
ping sediments generated from exposed areas
during surface mining operations. Once the min-
ing is  completed, and all disturbed areas  are
well stabilized, all sediment control structures,
as well as the accumulated  sediment,  should
be abandoned and/or disposed of in a  proper
manner.  If  proper  attention or consideration
is not given to postmining aspects in this area,
control structures as well as the accumulated
sediment may in time be carried into the streams
and  natural waterways during major storms.
By thus becoming part of the pollution problem,
the very purpose of their use in the first place
would  be defeated.  It  is, therefore, extremely
important  that  the disposal and dismantling
of all temporary control devices  be performed
before all mining equipment is demobilized from
the mining area.

Disposal of Accumulated Sediments

   Proper handling, disposal,  or abandoning
procedures for  trapped sediment  should  be
contained in  the original plans and specifica-
tions for surface mine development. In the event
that the accumulated sediment is to be left in
place, it should be covered, topsoiled, and vege-
tated, or stabilized by mechanical means,  to
prevent it from sliding or eroding back into the
stream.  If  the accumulated sediment is to  be
disposed of in a  predetermined  area within the
mine property, it should be spread in  layers,
dewatered,  covered with earth, and stabilized
by vegetation or mechanical means (fig. V-16).
The depth of  the layer will depend on the grain
size of the material being handled.

Dismantling of  Earth Embankments

   If the earth embankment is built  across a
natural  drainageway, the embankment and  all
           Figure V-15. Backhoe loading sediment irjto a truck for transport to a disposal area
                                             71

-------
accumulated sediment should be removed and
disposed of in a predetermined area within the
mine property. The natural stream should be
returned to its original profile and cross section.
The side slopes and bottom of the stream should:
be riprapped to prevent future erosion.
   If the embankment is built adjacent to the
natural waterway, it may be left in place by di-.
verting the entrance channel to the natural!
waterways, thus preventing any future surface
runoff from entering the impoundment.

Excavated Ponds

   Offchannel dugout ponds, which are usually
built by excavating a pit in the ground, should
be  backfilled,  preferably  with   the  material
constituting the embankment around them. The
backfilled  material should .be properly  com-
pacted. All areas disturbed as a result of this
operation should be stabilized with vegetation.
   If it is anticipated that the pond could serve
some useful purpose, it may be left in place.
However, precautions must be taken that no
surface runoff enters the pond  and that the
outflow channel from the pond is protected
against erosion.
  The ponds that are built by excavating the
streambed  to store sediment should be back-
filled so that the stream is brought back to its
original profile and cross section. The side slopes
and bottom of the channel should be stabilized
by mechanical and/or vegetative means.
                REFERENCES


   West  Virginia  Drainage  Handbook  for
 Surface Mining, prepared by Division of Plan-
 ning and Development and Division of Reclama-
 tion, Department  of Natural  Resources,  in
 cooperation  with  Soil  Conservation Service,
 U.S. Department of Agriculture.
   'Engineer's Handbook on Strip  Mining  in
 Eastern  Kentucky,  Department for Natural
 Resources and Environmental Protection, Com-
 monwealth of Kentucky.
   "C. W. Mallory and  M. A. Nawrocki, Contain-
 ment Area Facility Concepts for Dredged Mate-
 rial  Separation,  Drying,   and  RehanHling,
 prepared  by Hittman Associates,  Columbia,
 Md., for the Environmental Effects Laboratory,
 U.S. Army  Engineer Waterways Experiment
 Station,  Contract  No.  DACW 39-73-0-0136,
 Oct. 1974.
   5M. A. Nawrocki and J. M. Pietrzak, "Meth-
 ods to Control Fine-Grained Sediments Result-
 ing From Construction Activity," Draft Report
 HIT-648,  prepared  under EPA  Contract' No.
 68-01-3260, June 1976.
   3D. V. Kathuria, M. A. Nawrocki, and  B. C.
 Becker,  Effectiveness of Surface Mine  Sedi-
mentation Ponds, prepared by Hittman. Asso-
ciates, Columbia, Md., for the U.S. Environ-
mental Protection Agency, Office of Research
and  Development, Cincinnati, Ohio, Contract
No. 68-03-2139.    ,           .,'"'.
                 Figure V-16.  Diked sediment disposal area on relatively flat ground.
                                            72

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                                         Section  VI

                                     CONTROL PLAN
   The erosion and sediment control plan is the (
 blueprint that will enable the operator to mine
 the coal without choking adjacent streams with
.sediment.  The control  plan is  an important
 part  of the  overall mining and reclamation
 plan,  and  should consist of a comprehensive,
 explicit set of instructions  for controlling ero- j
 sion  and  sediment  during and after active
 .mining.  This section discusses  the  legal and
 technical considerations, the  makeup  of  the
 control plan, the information required to prepare
 the plan, as well as the procedure for preparing
 the plan.
   Preparation of an erosion and sediment con- j
 trol plan consists of five basic steps:            <

 •  Identification of legal and technical require-
   ments
 •  Collection and evaluation of site information |
 •  Development of a control strategy           |
 •  An interdisciplinary field review of the feasi-
   bility of the preliminary sketch plan
 •  Revision and finalization of the control plan

         LEGAL AND TECHNICAL
              REQUIREMENTS

   Prior to undertaking the preparation of an
erosion and sediment control plan, the surface
mine  operator,  or his engineer,  must become
knowledgeable of  both the  legal and technical
requirements of the State in which the operation
will be located. Legal considerations include
laws, regulations,  and design criteria at both
the State and Federal levels. These legal require-
ments vary considerably from State to State.
A summary of reclamation  requirements, both
legal and technical, in the States covered by the
manual is provided in  section IV, volume  II,
which  also includes a listing of the designated
reclamation  agency (agencies)  in each  State
that can provide the operator with the necessary
information.
   The reclamation  requirements usually ad-
dressed in  the State regulations include mine
drainage  restrictions,  highwall  restrictions,
topsoiling  requirements, revegetation  stand-
 ards, and grading requirements.  Some States
 also stipulate acceptable effluent standards for
 surface  coal  mining  operations.  Table .VI-1
 compares the Federal effluent standards for the
 surface coal mining industry with the standards
 set by three Appalachian States. It has not yet
 been definitively established that sedimentation
 basins can reliably meet these effluent stand-
 ards, particularly in .areas that have soils with
 high percentages of silt  and clays.  In such
 cases chemical treatment  becomes necessary
 and cost of control increases considerably.
   The erosion and sediment control plan is itself
 only one part of the overall mining and reclama-
 tion plan. The overall plan is made up of a com-
 bination of narrative description, construction
 plans and drawings, details, and specifications.
 Table VI-2 provides a complete checklist of the
 recommended erosion and sediment control plan
 components.  Depending on  individual  State
 preferences, this information may be mixed into
 the reclamation portion of the overall plan, or
 totally or partially segregated under the heading
 of "erosion and sediment control."
   EVALUATION OF SITE INFORMATION

   Conducting a thorough  site evaluation prior
to developing a mining plan is  an important
prerequisite to achieving cost-effective sediment
control. In addition to investigating the nature
and extent of the coal resources, the site evalua-
tion must  involve a complete investigation of
features directly and indirectly influencing soil
loss and the potential for offsite damage. Influ-
ential  features  include  topography, geology,
soil,  climate, hydrology, vegetation, and land
use.
   The site evaluation should be  performed by
individuals, or a team of individuals,  experi-
enced in the selection, design, and layout of both
surface mining  operations,  and  erosion  and
sediment control. The evaluation team should be
knowledgeable of earth and vegetative sciences
and capable of identifying the critical physical
features affecting erosion and sediment control.

-------
 The evaluation usually comprises a combination
 of published information surveys,  surface and
 subsurface investigations, and laboratory analy-
 ses.
   Sections  IV and V of this manual contain
 information on the relationship  of  various site
 features  to sedimentation processes  and  the
 use of control practices.

 Published Information

   Topographic maps, soil  maps and  surveys,
 vegetative maps,  geologic  maps and reports,
 and aerial photographs can be obtained, often
 free of charge, from various State and Federal
 agencies  and  institutions.  Table  VI-3  shows
 sources of such published information. To the
 experienced and trained individual  these docu-
 ments provide a valuable source  of information
 on physical features that relate  to erosion and
 sediment control.
   Local land use and  zoning maps  should also
 be consulted. These maps will  provide  informa-
 tion on current and projected  land  uses in the
 vicinity of the mine site, and will help  in deter-
 mining postmining land uses.

 Surface Investigation

   The primary purpose of the surface -investi-
gation is to identify, prior to preparation of the
 overall mining and reclamation  plan,  surface
 features having a major influence on soil loss
 and potential offsite  damage from  sediment.
 This work involves both a survey of available
 souces of published and, when available, unpub-
 lished information, and a thorough field investi-
 gation of  the  site and surrounding areas. The
 results of  this investigation,  along  with the
 findings from  the subsurface investigation, are
 needed to  identify mining practices  that will
 minimize  sediment damages and formulate a
 cost-effective erosion and sediment control plan.
   Surface  features   requiring   investigation
 include surface soils, drainageways, vegetation,
 and topography.
   The presence of highly erodible surface soils
 is a critical physical feature. This is especially
 true if these soils occur on  moderate to steep
 slopes. Soil credibility  should be  considered
 when locating access  roads and  other  offsite
 facilities, and in formulating plans for clearing,
 grubbing, and  scalping operations. The location
 and characteristics of streams and other natural
 drainageways deserve very careful examination
during the surface investigation.  Not only are
they the recipients of  sediment from  the mine
site and access roads  and transporters of sedi-
ment to areas farther downstream, but also they
themselves can contribute to the sediment load
through channel erosion. Increased surface run-
                       Table VI-1 .—Effluent standards for the surface mining industry
State
Federal 	
Kentucky 	
Pennsylvania 	
West Virginia 	

Turbidity or
suspended solids
30-100 mg/l
150Jtua
(b)
I
100 Jtu or less0
i
PH
60-Q f)
6 0-9 0
6 0-9 0
5 5-9 0

Total iron
mg/l
4n.7 n




Alkalinity

	 .'|l! 'I
1 ' ' ' ' 1 ,'il ' ' "


   "The discharge shall contain nosettleable matter, nor shall it contain suspended matter in excess of 150 Jackson turbidity units
 (Jtu), except during a precipitation event, which the operator must show to have occurred, in which case 1,000 Jtu may not be
 exceeded.
    No silt, coal mine solids, rock debris, dirt, and clay shall pe washed, conveyed, or otherwise deposited to the waters of the
 Commonwealth.                                    '.
   "Turbidity—not more than 1,000 Jtu 4 hours following a major precipitation event and not more than 200 Jtu after 24 hours
 (major precipitation event = 1/2 inch of rainfall in 30 minutes).  [                       '.          '     "
   Source: D. V. Kathuria, M. A. Nawrocki, and B. C. Becker.'Effectiveness of Surface Mine Sedimentation Ponds, prepared by
 Hittman Associates, Columbia, Md., for the U.S. Environmental Protection Agency, Office of Research and Development Cincinnati
 Ohio.                                            ,                                        '  ...    '
                                               74

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                     Table VI-2.—Information checklist for an erosion and sediment control plan
Background information:

       1.  General:

             Location of project
             Extent of area to be affected
             Type of mining operation
             Evidence of compliance with State's legal
                requirements

       2.  Site inventory:

           •  Topography
             Geologic analysis
             Soil analysis
             Climatic analysis
   ,          Hydrologic analysis
             Vegetative analysis
             Land use analysis
Schedule of activities:

      Site preparation:

             1. Access roads:

                   Plan view (location)
                   Typical cross section
                   Profiles
                   Maintenance requirements and schedule

             2. Drainage and sediment control structures:

                   Plan view (location)
                   Typical cross sections
                   Details (where needed)
                   Design computations (where needed)
                   Maintenance requirements and schedule

             3. Clearing and grubbing:

                   Plan views of limits of areas to be cleared
                   Description of procedure
                   Machinery to be used
                   Method of disposing of timber, brush, and
                     waste materials
                   Identification of critical areas requiring
                     temporary stabilization
      Mining operations:

            1. Scalping:

                  Method of scalping topsoil material
                  Equipment to be used
                  Plan view of topsoil storage areas
                  Temporary vegetative stabilization of
                      stockpile areas
Schedule of activities—continued:

      Mining operations—continued:

            2. Overburden handling:
                   Method of overburden handling
                   Handling of first cut
                   Plan view of overburden storage
                      areas "
                   Stormwater handling in overburden
                      storage areas
                   Temporary stabilisation measures
                   Permanent stabilization measures
     Reclamation operations:

             1. Handling of toxic material:

                   Method of handling toxic material
                   Equipment to be used

             2. Spoil rehandling and grading:

                   Typical cross section of regrading
                   Equipment to be used
                   Method of spreading topsoil or upper
                      horizon material on the regraded
                      area,  including approximate
                      thickness of the  final surfacing
                      material
                   Method  of drainage control for the
                      final regraded area

             3. Revegetation:

                   Method to be used
                   Surface preparation
                   Type of vegetation
                   Fertilizer application (method and
          .            rate)
                   Seasonal revegetation schedule and
                      rate
                   Mulch  application (method and rate)
                   Maintenance requirements and sched-
                      ule

            4. Mine abandonment:

                   Method fordisposal and stabilization
                      of  drainage structures not cov-
                      ered above, particularly sediment
                      basins
                   Method for stabilization and/or aban-
                      donment of haul road
                  Assignment of responsibility for any
                      permanent structures  left behind
                  Maintenance  program and schedule
                      for any permanent structures left
                      behind

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                                    Table \f\-3.-Published information aids
        Informational aid
           Where obtained
      Information available
Aerial photographs
   to  LANDSAT imagery .
Topographic maps
Soil surveys.
Vegetative maps.
Geologic maps and reports
East of the Mississippi River:
   U.S. Geological Survey, Distribution
   Center, 1200 South Eads St.,
   Arlington, Va.  22202
West of the Mississippi River:
   U.S. Geological Survey, Federal
   Center Bldg. 41, Denver, Colo. 80225
Local air services
U.S. Soil Conservation Service (SCS)
U.S. Forest Service
Agricultural Stabilization and
   Conservation Service
NASA
EROS Data Center, Sioux Falls, S.Dak.


Same as aerial photographs
U.S. Soil Conservation Service,
   Independence Ave. between 12th and
   14th Sts.,S.W., Washington, D.C.
Local Soil Conservation Service office
See section IV, volume II, for complete
   list of counties with surveys.
U.S. Department of Agriculture,
   Independence Ave. between 12th and
   14th Sts.,S.W., Washington, D.C.
U.S. Forest Service
State forestry division
State agriculture division
Local universities
Infrared and other aerial photographs

Universities         ;
U.S. Geological Survey
State geological  survey
1. Drainage networks
2. Land forms
3. Extent of colluvium, alluvium,
      and other
4. Vegetative patterns (infrared)
5. Fracturing  and jointing patterns
6. Slope gradients
7. Location of mass movements
8. Land cover characteristics
1. Benchmarks
2. Slope gradients
3. Location of roads, buildings, and
      nearest towns
4. Drainage basins
5. Relief
6. Stream systems


1. Types of soils
2. Extent of various soils
3. Engineering properties of soils
4. Land  use potentials  for .various
      soils
5. Erodibility of soils
6. Aerial photographs        ,
7. General textural characteristics
      of the soils

1. Types and extent of vegetative
      cover
2. Density of cover
1. Kinds of strata
2. Location of geologic hazards
      a. Faults
      b. High-water tables
3. Strikes and dips of various strata
4. Geologic trends in the area
5. Topographic features and their
      relationship to the geology
                                                    76

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  off resulting from both mining and construction
  and sedimentation  of the  channel is  a factor
  contributing to channel degradation. The gradi-
  ent, alignment configuration, and the nature
  of the material lining the channel determine the
  susceptibility of the stream to erosion and its
  ability to transport sediment. Stream biology
  and recreational, industrial, and municipal uses
  are  major considerations in determining the
  level of sensitivity to sediment pollution.
    Streams and other drainageways intercepted
  by the mining operations and access roads will
  require very special attention, both during and
  following mining, if costly  offsite damages are
  to be avoided.
    Natural ground slope and vegetative cover
  will also have a major bearing on the potential
  for offsite damage.  Fairly  flat,  well-vegetated
  buffer areas  found below a mine site or access
  road are a major deterrent to the movement of
  sediment into  waterways.  On steeply sloping
  terrain where a good buffer area  is  not  present,
  very careful consideration  must be given to
  handling of sediment-laden runoff. •
   Water quality should  also be studied during
  the surface investigations.  If initial investiga-
  tions indicate the suspended solids concentra-
 tion is high due to natural causes or other land
 disturbances in upper portions of the watershed,
 it would be  advisable to monitor the site and,
 thereby, more accurately establish the baseline
 conditions.
   Potential  roadway  alignments, head-of-
 hollow fill areas, and other outslope spoil dis-
 posal areas require careful examination to locate
 possible  landslide areas. Such  areas  include
 slopes containing ground water seeps, unstable
 soil, or bedrock material.


 Subsurface Investigation

   The  subsurface investigation should not be
 limited to the identification  of those geological
 features, soil, and overburden properties which
 relate to mining  and geotechnical engineering
 and acid mine drainage.  It should also  be uti-
 lized to determine those chemical and physical
 properties of the overburden (both soil and bed-
 rock) which influence credibility and capability
 to sustain a long-term vegetative cover.
   Erodibility factors  to  be examined include
 texture and permeability of soil material, weath-
 ering characteristics  of  fragmented bedrock
 materials, and clay mineralogy (sec. IV). This
 information will  help in  identifying suitable
 topsoiling material, grading (slope length and
 steepness) requirements, and the sophistication
of perimeter sediment control practices.
  From the  standpoint  of  revegetation,  the
  identification of suitable topsoiling material is
  extremely important. This will require an evalu-
  ation of surface soils to determine  their suit-
  ability for salvage and use as topsoiling mate-
  rial, and a study of other overburden material,
  including shales and other bedrock materials, to
  determine whether or not they are more suitable
  for use as topsoiling material (fig. VI-1). Impor-
  tant parameters to be studied when evaluating
  overburden  materials  for  use  as  topsoiling
  material are texture, pH,  and nutrient level.
  Organic content and weed seed content are also
  looked at when evaluating surface soils.
    Texture (i.e., size and gradation of soil par-
  ticles) and organic content will  determine the
  ability of  a soil to absorb surface water and to
 retain water  for use by vegetation. This latter
 characteristic is referred to as moisture-holding
 capacity.  When evaluating textural properties
 of bedrock materials, fragmentation (i.e., size
 of rock particles after blasting) and weathering
 characteristics must also be considered.
    Problems related to pH are common and must
 always be investigated. Excessively acidic soils
 will require periodic applications of crushed or
 pulverized limestone or dolomitic limestone in
 order to maintain a good vegetative cover. If
 the pH problem is not too severe, the use of
 vegetation with  acid-tolerant characteristics
 may be in  order. The major elements that affect
 the nutrient level of the soil are nitrogen, potas-
 sium, and phosphorus. Soils  (spoils) deficient
 in these nutrients will require periodic applica-
 tions of fertilizers selected on the basis of soil
 tests.
   Clay mineralogy is also an  important factor
 to  be examined when evaluating possible top-
 soiling material. The presence of large quantities
 of highly expansive or "fat" clays, such as ben-
 tonite or montmorillonite, in a soil will decrease
 its  permeability  significantly, thus  reducing
 infiltration and,  ultimately, the ability  of the
 soil to support vegetation.
   Overburden samples for conducting various
 tests can be obtained while drilling to evaluate
 the coal deposits (fig. VI-2).   However,  addi-
 tional coring may be required to get unblended
 samples  of the overburden material. Surface
 soil samples can be easily obtained using hand-
 sampling  techniques.  Where deep soils exist,
 test pits may  be required to gather visual infor-
 mation and collect  good  samples for testing.
   Further  guidance in performing subsurface
 investigations, conducting various tests, and
 in evaluating  results can be obtained  from the
 Soil Conservation Service (SCS) district or State
office, and from the State geological survey.
State offices of these agencies are listed in sec-
tion IV, volume II.

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                               Figure VI-1.  Gathering topsoil sample.
Climatic Data

   The gathering and assessment of climatic
data are also important in the preparation of
an erosion and sediment control plan. Important
climatic factors to be investigated include rain-
fall frequency, duration, and intensity and tem-
perature, sunlight, and radiation.
   The following functions require a knowledge
of climatic factors:

•  Design of drainage systems for access roads:
   When designing a drainage system, informa-
   tion must be obtained on expected frequen-
   cies, intensities,  and  durations of severe
   storms (usually a 10- to 25-year frequency).
   Culverts, ditches, and other structural con-
   trol features must be sized to handle the
   anticipated storm runoff.
•  Location and sizing of stormwater and sedi-
   ment detention facilities: Whereas the other
   elements of the drainage system are designed
   to handle a peak flow  rate for a selected de-
   sign storm,  sediment  basins and traps are
   designed to store a certain volume of runoff
   water. This  design requires a knowledge of
   rainfall parameters.
•  The scheduling of construction, mining, and
   reclamation  operations:  These  operations
Figure VI-2. Core drilling to gather information on
             overburden and coal.
                                              78

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   should be scheduled to minimize the area of
   soil exposed during periods of  heavy and
   high-intensity rainfall. Information concern-
   ing average precipitation and rainfall inten-
   sity for various months is required to sched-
   ule such activities properly.
•  Selection of plant materials and timing of
   revegetation:  Climatic variables  such  as
   temperature, radiation, evapotranspiration,
   precipitation, and soil moisture storage have
   a direct bearing on seed selection and plant
   development.  Through  consultation  with
   State  reclamation personnel,  SCS, and de-
   partments of forestry and agronomy in State
   universities,  a seeding plan  and planting
   schedule  should be selected that will be con-
   ducive to rapid and sustained plant growth.

Information concerning the  climatic variables
is obtainable  from local airports and the U.S.
Weather Service.  Rainfall intensity, duratipn,
and frequency curves  and maps  are usually
available from these sources.       .-.'.'-
I
           CONTROL STRATEGY
  The development  of a sound erosion and
sediment control strategy tailored to the mine
site and  affected off site areas is the third step
in preparing an erosion and sediment control
plan.:
  The control rationale presented in section
III outlined the basic principles to be followed
in developing  a  control strategy. That basic
philosophy must be applied in the development
of a site-specific control strategy, particularly
with respect to the selection of the mining oper-
ations and control measures.

             Mining Operations
  The development of a control  strategy begins
with the  selection of mining practices to be used
at the site and the identification of areas to be
disturbed during mining (fig. VI-3). The mining
practices selected are based on site conditions
as defined in  the  site  evaluation, legal  con-
straints such as State and Federal regulations,
                                        iS^§S€j-^?'--*iS2j" /";''•**"P*-\v"/'i;
                                              \
                              Figure VI-3. Area mining in the Midwest.
                                              |79

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                                                     r"~ T.'~.~ -,	,,,,,,,,.,.,,,-.,,„..„,	,	„,
                                                     " I'*w-frt>v;*!;;	
                         Figure VI-4.  Haulback contour mining in Appalachia.
 and an array of other factors,  most of which
 relate to economics. The overall economic analy-
 sis is, of course, influenced by the cost of various
 environmental controls, including erosion and
 sediment control.
   A  summary of the basic environmental ad-
 vantages and disadvantages of various mining
 methods has been described by Hill and Grim in
Environmental Protection in Surface Mining of
 Coal.1 From that summary one can ascertain
 that certain mining methods such as the block
 cut method, mountain top removal, and  area
mining generally have, from the standpoint of
soil  loss potential,  an advantage  over other
methods because less land is usually disturbed.
 It has been demonstrated2 that, when mining on
a  steep slope, erosion and sedimentation  are
directly proportional to the amount of land dis-
turbed.
   To reduce the opportunity for offsite  sedi-
ment damage, the operations should be designed
to limit the amount of land disturbed by retain-
ing as much as possible of the spoil on the site
and  minimizing outslope disposal  (fig. VI-4).
Spoil placement, disposition, and stabilization
should be well documented in the control plan.
   After the mining method has been selected, a
complete schedule of mining operations can be
developed. A schedule of activities is necessary
 in order to be able to stage the operations prop-
 erly so that both the area and time (i.e., duration
 and season)  of  exposure can  be minimized.
 Although time is not as tangible as labor, mate-
 rials, or equipment, it still remains a critical
 element in erosion and sediment control.
   Sediment  production can  be  decreased by
 reducing the size of the area that is disturbed at
 any given time and the length of time during
 which any area is left exposed. These two basic
 facts call for a control strategy that involves
 staging of activities to reduce both the area and
 time of exposure.
   The location of  areas to be mined, access
 roads, and other offsite facilities must also be
 defined in this stage of the development of a
 control strategy.  The boundary of the property
 to be mined  and  the location  of roadways and
 other facilities should be influenced by the
 results of the site investigation. This is  espe-
 cially important when  selecting roadway align-
 ments and outslope spoil disposal areas.
  Multiple uses of access roads is often forgot-
 ten in the planning stage. Roads can frequently
 be used before mining for logging, and  after
mining for access to the mine  area for fire pro-
 tection, housing developments, hunting, or other
uses. Well-built roads  result in faster haulage
time and cost less to maintain.
                                             80

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Control Measures
   Once the mining techniques and the boundary
of the property to be mined are known and the
location of access roads and other offsite facili-
ties is established, individual erosion and sedi-
ment control measures can be identified, sited,
arid scheduled.
   Sections III, IV, and V of this manual pro-
vide information on control rationale and the use
of various control practices. Section I, volume II,
contains more detailed information on selected
control  practices.  This information should be
consulted when identifying various erosion and
sediment control measures to be used at a spe-
cific site.
   The control strategy must include a combina-
tion of perimeter and internal erosion and sedi-
ment control practices  (fig. VI-5).  Drainage
upslope of the disturbed areas must be diverted
properly around or through the disturbed area,
and both  internal and perimeter control prac-
tices must be deployed to reduce the amount of
sediment leaving the mine site and access roads
and entering waterways.
   Scheduling of control measures is also  a very
important consideration. Prior to clearing, con-
 struction of access  roads, or the initiation of
 any other earth-disturbing activities, perimeter
 control measures, such as diversion structures,
 sediment traps, and basins, must  be installed
 (fig. VI-6).  In highly inaccessible areas, some
 variance from this general rule will be required
 in order to gain access to the site for equipment
 needed to construct control measures.
   Onsite erosion control and sediment contain-
 ment practices should also be implemented in a
 timely manner and should be performed concur-
 rently with excavation and grading activities.
   Revegetation practices require close schedul-
 ing. Seasonal considerations, in particular,  are
 very important in the successful establishment
 of vegetation.  Seedbed preparation should be
 scheduled to coincide as closely as possible with
 completion  of final  grading. Extensive  delays
 may, in some instances,  necessitate the use
 of short-term stabilization practices, such as
 chemical stabilization, vegetation, or mulching.
  , In the identification of control practices,
maintenance considerations must not be over-
looked. Lack of maintenance is  a major factor
in the failure of  many control programs. The
operator must be constantly on the lookout  for
  Figure VI-5. Contour furrows and diversion swale controlling erosion and protecting lower lying waterway.
                                             81

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Figure VI-6. Diversion ditch along perimeter of disturbed area.

   Figure VI-7.  Sediment basin badly in need of cleaning.
                          82

-------
erosion and sedimentation problems and must
take prompt  and effective  action  to  correct
identified problems. Particular attention should
be given to inspecting,and maintaining water-
Handling structures such  as diversion, down-
drain,  and  channel stabilization structures and
sediment traps arid basins  (fig. VI-7). Breaches
in stabilization and diversion structures and
the accuriiulation of excessive amounts  of sedi-
ment in containment structures should be antici-
pated,  and procedures should  be identified to
correct such problems.          '
  The  access  and haul roads,  in  particular,
require a  thorough maintenance program to
maintain a desirable operating quality and to
control erosion. Stabilization measures, as de-
scribed in section IV, should apply to the road-
base, drainage appurtenances, and cut-and-fill
slopes.  Frequent inspections of these elements
should be made to insure their functional integ-
rity.
   Considerable attention  must  also be  given
to   inspecting  and   maintaining  vegetative
practices. Vegetation  is a living material and
requires oxygen,  moisture,  and nutrients  to
survive. Periodic  applications  of various soil
amendments, such as lime and fertilizers, will be
required to establish a ground cover that will
provide long-term protection against soil ero-
sion. Maintenance requirements  can be mini-
mized   by  selecting plant materials that are
suited to natural site conditions and postmining
land use.
   The erosion and sediment control plan should
clearly define both scheduling and maintenance
requirements. For vegetative practices, it should
also specify the following:

   Planting location
   Species to be used and application rates
   Methods of planting or seeding
   Seedbed preparation procedures         _ •'.
   Liming, fertilization, and mulching  require-
   ments, including types of material to be used
   and application rates
   Planting schedule
      EVALUATION OF PRELIMINARY
               SKETCH PLAN
                                              |
                                              (
   After the required legal and technical infor- j
 mation has been collected and analyzed, and a {
 control strategy has  been formulated, a pre- j
 liminary  sketch plan  is prepared. This sketch :
 plan shows the approximate location of prospec- j
 tive access  roads,  mining areas, and  control
 structures, and defines procedures to minimize j
 erosion and control damage. The sketch plan j
provides the operator, or his engineer, with a
working document that can be taken to the field
to evaluate the feasibility of the plan.
  After the preliminary plan has been prepared,
the operator, or his engineer, should contact all
the appropriate Federal, State, and local govern-
ment agency representatives, and schedule an
interdisciplinary field conference at the proposed •
site. Appropriate or  responsible government
agencies vary from State to State;  however,
representatives from agencies such as the State
division of reclamation,  SCS, the  department
of natural resources, the U.S. Geological Sur-
vey, and the U.S. Forest Service are generally
included.  In addition, any  applicable local or
regional governmental agency  should  be  iri-
cluded. In some  cases representatives of local
citizen groups, such as the League of Women
Voters, are invited to attend this conference.
A listing of the respective agencies in each State
is provided in section IV, volume II.
  " A conference of this type provides the follow-
ing benefits:

• It provides a unique opportunity for an inter-
  disciplinary  evaluation  of  the  proposed
  mining project by a highly skilled group of
  professionals
• The inclusion of the responsible government
   agencies in  the formulation  of the control
   plan means that delays usually encountered
   in obtaining final  plan approval will be re-
   duced.
• This interdisciplinary approach will balance
   the influence of the various  individual dis-
   ciplines and minimize oversights that could
   develop into serious problems at a later date.
• The conference will provide the beginning of
   a cooperative  effort to mine  the mineral re-
   source while protecting the environment.
       REVISION AND FINALIZATION
                OF THE PLAN

   Suggestions  or revisions resulting from the
 field conference are then incorporated with the
 preliminary plan and used to prepare a detailed
 final plan in accordance with the checklist pro-
 vided in table VI-2. This final plan is then sub-
 mitted to the responsible government agency
 for approval. The plan will either be approved
 and a permit issued, or it will be returned for
 corrections or revisions. In the latter case, the
 corrections or revisions will be made to the final
 plan and the plan will then be resubmitted for
 approval.  A representative erosion and  sedi-
 ment control plan is presented in section III,
 volume II.
                                               83

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               REFERENCES
  'Elmore C. Grim, and R.  D. Hill, Environ-
mental Protection in Surface Mining of Coal,
Environmental  Protection Technology  Series,
EPA-670/2-74-093, Oct. 1974.
  2Design of Surface Mining Systems in East-
ern Kentucky, vol.  II, Report  ARC-71-66-71,
prepared by Mathematica,  Inc.,  and Ford,
Bacon and Davis, Lexington, Ky., for the Appa-
lachian Regional Commission, 1974.
                                          84

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                                        Section  VII
                                   IMPLEMENTATION
   Issuance of a mining permit signifies that
 the  mining plan is  an acceptable operational
 program designed to maximize productivity and
 minimize environmental damage. However, mine
 productivity and environmental protection are
 not  assured by the design of the plan, but by
 its successful implementation. It is well recog-
 nized that a key to success in nearly all aspects
 of surface mining  is  onsite supervision and
 inspection. Just as supervision and inspection
 are required for the efficient removal of coal,
 these functions must also be applied to achieve
 effective sediment control. This on-the-ground
 phase  of  erosion and sediment  control is the
 responsibility of two field specialists—the mine
operator, or foreman, and the State surface mine
inspector.

     INSPECTION RESPONSIBILITIES

  To assure that the mining operation is  con-
ducted in accordance with the control plan, the
operator and the inspector must function  as a
team (fig. VII-1). Their success depends on how
well each  of them performs their duties,  how
well they work together, and the thoroughness
of their field investigations.  Section VII  pro-
vides descriptions of the individual responsi-
bilities of the  operator and the inspector,  and
presents some guidelines for field inspection.
«333ftf*<'»,-   .           '"  *
(ffi^Sfc*1*^***
^itiiisf wgKsJ^^-irv.-.,
~-*ifc;*K5«jL. .•.- ' -',";--.*? .^s»>*^":-r;;
            ^--^SiT^.'
fe^'^*4^*>fe^;s
^*c,'i«4-;»s?i i>'»«a1-^ "^^s-^
^SSf^JS^iife'/^J^i-

                                                                                          ,'
                                                         j5»J' -^ *• ^,*   :•:* * •••
                                                         s-,'' -*&*&••;•• -   j*.^.- '?w-_i •
                             Figure VII-1. Opera'tor-inspectorteam.
                                            m
                                             i

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The Operator's Responsibilities

   The man responsible for the day-to-day opera-
tion of the mine, the operator, has possibly the
most important role in coal surface mining. In
addition to mining coal efficiently and rapidly,
he has the equally important jobs of following
the approved mining plan, scheduling the opera-
tion so that everything is kept current, meeting
production  schedules,  and  talking with  the
inspector and other State officials.
   The operator's  performance  will determine
the success or failure  of the mining operation.
Mine-closing orders or noncompliance citations
often result when the operator fails to carry out
the mining operation  as specified  in the  ap-
proved plan, or when unforeseen problems or
failures develop, and are not corrected.
 _ The Virginia Surface Mining and Reclama-
tion Association,  drawing from its experience
with  mine operators and the general public,
has provided its surface mine operators with a
list of do's and don'ts. This list has been adapted
for general use and is presented below.           ',

  DO—Buy  an inexpensive  camera, a  .soil-
     testing kit, and a water-testing kit. Photo-
     graph  and test the area before, during, and
    after  mining. Prepare  and  maintain  a
    logbook on each operation, being careful to
    note specific facts such as  soil  and water
    pH and silt  levels. Sign  and  date  each
    entry.  Such a log  can be extremely useful
    should questions arise regarding the spe-
    cific effects of the operation on the area
    being mined.

  DO—Be  sure that water impounded on the
    bench  is released  gradually (i.e., pumped  :
    or siphoned), and that provisions are made
    to prevent erosion  and siltation of streams.

  DO—Keep  your (haul and/or access) roads
    in good repair and properly ditched. A few
    hours each week spent on this work can
    save days of costly effort later.

  DO—Listen to complaints about your opera-
    tion even if the complaining party appears
    unreasonable. Try to find out what is really
    wanted. If you cannot satisfy  his entire
    request,  a  compromise  can  usually  be
    worked out. If a difficult situation arises   '
    regarding- a complaint, seek assistance in
    working out a fair settlement.

 DO—Advise  nearby  residents  of planned
    blasting so they will know what  to expect.
    If elderly or ill persons are nearby,  offer
    them transportation to and from a friend's
   or  relative's  home  away from  the area
   during the shot. This is the fair and cour-
   teous thing to do.

 DO—Keep regrading current. It is hard to
   catch up once you get behind.

 DO—Obtain designated  State  or  Federal
   agency approval of regraded areas before
   applying seed and  fertilizer.  Otherwise,
   some  expensive reworking could be re-
   quired.

 DO—Order only certified seed and fertilizer,
   far enough in advance  to insure delivery
   before needed. This will assure that all
   arrangements are made in time to prevent
   expensive  delays. Have  a storage  area
   available if materials must be stored before
   delivery to the job.

 DO—Be  extra  careful when working  near
   homes or public roads. Plan the job,care-
   fully, work the job responsibly, and reclaim
   the job better than the law requires. Even
   though your  work  might be  perfectly
   acceptable, you  and the industry will be
   criticized if the job looks bad.

 DO—Perform touchup  work on seeding and
   fertilizing as  soon  as rough spots are ap-
   parent. The sooner the work is satisfactory,
   the sooner you will be released from your
   obligations.

 DO—Publicize  especially  good reclamation
   work.  Make use of available news media
   (i.e., newspapers, television,  trade maga-
   zines, etc.).

 DO—Make sure all of your employees under-
   stand  the importance  of handling black
   material  properly. In 99 percent of the
   cases,  plants  will not grow on the black
   material. Even if it is not acid, it will ab-
   sorb so much  heat from the sun that vege-
   tation will not grow.

 DON'T—Be too quick to criticize the enforce-
   ment agency. These  men  have a difficult
   job, especially with a new law to enforce.
   They will be fair if at all possible. Consider-
   ation, understanding, and cooperation by
   all concerned  parties in  dealing  with a
   problem  will  result in the best  possible
   solution.

DON'T—Be afraid  to ask for assistance if
   unexpected difficulties  arise.  Numerous
   State and Federal agencies as well as coal
   associations provide technical advice when
   needed.
                                             86

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DON'T—Let  trucks and  equipment  run
  through a creek.  A culvert or a simple
  bridge is not costly, and the people down-
  stream will not have  a muddy creek (fig.
  VI1-2). Mining operations can  be shut
  down for polluting waterways. This can be
  costly.
DON'T—Let trucks and equipment run mud
  onto a highway. Such a practice is annoy-
  ing to the public, can cause accidents, and
  in some States is illegal and can result in a
  shutdown.                              I
DON'T—Forget  that one careless act can)
  make a bad impression for the whole indus-1
 • try.                                    I
The Inspector's Responsibilities

  The responsibility  assigned to the surface
mine inspector is  different in every coal pro-
ducing State. However, all inspectors have some
degree of enforcement power that can be exer-
cised when mining laws are violated (fig. VII-3).
  The surface mine inspector has  the  job of
being a spokesman for the State, visiting mining
sites,  making  reports, and  giving technical
guidance. In addition to his role as an inspector,
he oftentimes must serve as  engineer, agrono-
mist, and geologist to the mining operator.
  General inspection responsibilities  that the
mine inspector must carry out include the fol-
lowing:

                    Figure VI1-2.  Protect streams by providing stable crossings
                                            87

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                                                                                         'r•'".-" * I
                         Figure VII-3.  Water sampling below surface mine site.
  •  Meeting  with the  operator  and  becoming
    knowledgeable on the type of mining opera-
    tion, water-handling practices, and reclama-
    tion work.
  •  Scheduling visits with the operator, especially
    at critical times
  •  Advising mine operators on the best possible
    methods of controlling pollution caused by
    erosion, sedimentation, and acid mine drain-
    age
 •  Insuring that all phases and  aspects  of the
    active operation are within the constraints of
    the law and according to the plan
 • Keeping time schedules on the mining and
   reclamation phases of the operation to insure
   that both phases are being kept as current as
   possible

   The  degree of competence with which  an
inspector  carries  out his responsibilities will
depend on  four major factors:

« Training
• Personality
• Incentives
•  Intelligence

  Training. The surface mine inspector must be
knowledgeable in  surface mining technology,
reclamation, State and Federal laws relating to
 surface coal mining,  and various  other  dis-
 ciplines.  Minimum training  should include a
 balanced combination of classroom and field
 training. Classroom training should be sufficient
 to make the inspector knowledgeable in  the
 areas mentioned above.  Field training should
 be conducted under the supervision of an experi-
 enced inspector before the trainee is assigned a
 work area.
   Personality. It  is especially important for a
 surface mine inspector to have  an agreeable
 personality. With each new mining permit the
 inspector will meet another operator with a dis-
 tinct personality unlike his own. The inspector
 must have  a personality  that is both firm and
 businesslike, yet possess an ability to laugh and
 be cooperative.
   Incentives.  Through awards, educational
 benefits, and other incentives a sense of pride,
 competitiveness, and increased  spirit  can be
 instilled in a very hard and burdensome job.
   Intelligence. As in any other technical pro-
 fession, the mine inspector  must be intelligent
 enough to  do his job in  a  knowledgeable and
professional manner. His inspection responsi-
bilities  make it necessary for him to  acquire
skills in new and often complicated technical
areas. This  required knowledge can be gained
                                              88

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through  seminars,  training  sessions,  confer-
ences, and meetings dealing with various aspects
of surface mining.
     GUIDES FOR INSPECTION AND
     EVALUATION OF EROSION AND
   SEDIMENT CONTROL MEASURES
          ONSITE PLAN  REVIEW


  Following the issuance of ,a mining permit it
is  necessary that the operator and the area
mining inspector meet and review  the  entire
mining plan in  the field.  By doing this, the
following objectives can be achieved:

• The inspector can become more familiar with
  site conditions that will be affected by the
  mining operation. This will help the inspector
  when  making future  visits and  assessing
  changes in the  mining operation and the
  mining environment.
• Further discussion can take place between the
  operator and  the inspector of specific prob-
  lems that may be encountered  during the
  operation (e.g., becoming spoil bound).
• The inspector can make suggestions and pro-
  vide information to the operator that may
  help the operator mine coal more efficiently,
  and remain within the constraints of the law.
• By reviewing the mining plan in the field and
  walking the site, the operator and inspector
  can begin a cooperative relationship that will
  be helpful in achieving both men's goals.
           ONSITE INSPECTION


   The working relationship between the opera-
 tor and the inspector  is probably  most  pro-
 nounced  in  their  routine  onsite  inspection
 duties. The operator has the best working knowl^
 edge  of the site and is in the best position to
 take  prompt preventive or corrective actions.
 The inspector has less working knowledge about
 any one site, but has a better overall view of
 problems and conditions in the area. The inspec-
 tor is in the best position to evaluate objectively
 the total performance of the erosion and sedi-
 ment control efforts on a site. With these com-
 plementary points of view working together, the
 onsite inspection can be the most valuable ele-
 ment of an entire  control program—provided
 that  inspections are sufficiently thorough. A
 partial list of items to be checked on inspection
 tours is given below. This list has been adapted
 in part from the Sediment  Control Inspectors
 Handbook of the Maryland Water  Resources
 Administration.
1. Haul and access roads
  a. Alignment
     (1)  stream crossings
     (2)  curves
  b. Road grades
     (1)  steepness
     (2)  length
  c. Road base materials
  d. Drainage
     (I)  road cross section
     (2)  outlet spacing
     (3)  channel lining
     (4)  energy dissipators

2. Clearing and grubbing
  a. Description of method and equipment
  b. Staging schedule
  c. Brush and trash disposal

3. Water-handling structures
  a. Diversion dike
     (1)  location
     (2)  top width
     (3)  height
     (4)  machine compaction
     (5)  side slopes
     (6)  grade
     (7)  outlet
     (8)  vegetative stabilization
  b. Interceptor dike
     (1)  location
     (2)  top width       .'..'
     (3)  height        .         ,
     (4)  side slopes
     (5)  machine compaction
     (6)  grade            ,         ,
     (7)  spacing                   .
     (8)  outlet                .
     (9)  vegetative stabilization
     Level spreader
     (1)  location
     (2)  bottom width
     (3)  back slope
     (4)  length
     (5)  grade
     (6)  outlet
     (7)  vegetative stabilization
  d. Grassed waterway or outlet
     (1)  location
     (2)  depth
     (3)  width
     (4)  slope
     (5;  subsurface
c.
                                             189

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       (6) compaction
       (7) vegetative stabilization
       (8) temporary protection during establish-
          ment (when possible)
    e.  Diversions
       (1) location
       (2) cross section
       (3) grade
       (4) outlet
       (5) vegetative stabilization
    f.  Grade stabilization structure, chute, or
       flume
       (1) location
       (2) lining
       (3) size and cross section
       (4) compaction
       (5) slopes
       (6) placement of lining
       (7) subsurface
       (8) outfall
    g.  Sediment basin
       (1) location
       (2) size of storage area
       (3) pipe spillway
          (a) location of riser and barrel
          (b) size and elevation of riser and bar-
             rel
          (c) spacing and size of the perforations
             in the upper one-half to 2-thirds of
             the riser
          (d) antivortex device on top of riser (if
             required)
          (e) riser base
          (f) trash rack (if required)
          (g) antiseep collars
      (4) emergency spillway (if required)
          (a) location
          (b) size—bottom, side slopes, length
         (c) elevation
         (d) vegetative stabilization (or other
             suitable means)
      (5) embankment (dam)
         (a) site preparation
         (b) material
         (c) compaction  (lifts)
         (d) size—top width, side slopes, length
         (e) elevation (freeboard)
         (f) vegetative stabilization (if required)
      (6) maintenance cleanout
   h.  Straw bale dike or berm (extra)
      (1) location
      (2) size
      (3) binding
      (4) key trench and backfill
      (5) rebar or stake pegging
   i.  Other as appropriate

4. Stockpiles (topsoil and overburden)
   a. Location
   b. Water handling
   c. Stabilization
      (1) vegetative
      (2) other

 5. Regrading
   a. Staging
   b. Burial of toxic material
   c.  Ground water drainage
   d. Slope control
      (1) steepness
      (2) length
   e.  Soil reconstruction
   f.  Surface drainage

6.  Revegetation
   a.  Critical area stabilization with temporary
      seedings
      (1) location
      (2) duration of use
      (3) site preparation
      (4) seedbed  preparation (lime, fertilizer,
         disking)
      (5) seeding (mixture and application meth-
         od and rate)
      (6) mulching
      (7) establishment (cover density and main-
         tenance)
   b.  Critical  area  stabilization  with  semi-
     permanent and permanent seedings
      (1) location
      (2) duration of use
      (3) soil conditions  (long-lived vegetative
         cover)
     (4) site preparation
     (5) seedbed preparation (lime,  fertilizer,
         disking)
     (6)  seeding (mixture and application meth-
         od and rate)
     (7)  mulching
     (8)  establishment (cover density, mainte-
        nance, and irrigation, if necessary)
  c.  Critical area  stabilization with mulching
     only
     (1)  location
     (2)  duration of use
     (3)  site preparation
     (4) mulching (materials and application,
        cover density)
     (5) mulch anchoring
  d.  Critical area  stabilization with Bermuda-
     grass, grasses, and legumes
     (1) location
     (2) site conditions (limitations)
     (3) site preparation
     (4) soil preparation
     (5) establishment (sprigging)
     (6) maintenance
  e.  Critical area stabilization with sod
                                               90

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f.
(1)  location
(2)  soil preparation ,(lime,  fertilizer,  and
    tillage)
(3)  sod materials and installation
(4)  maintenance (watering, and mowing)
Critical area stabilization with ground cov-
ers, vines, shrubs, and trees
(1)  location
   (2)  planting time
   (3)  soil preparation
   (4)  mulching
   (5)  maintenance
g. Topsoiling
   (1)  location
   (2)  subsoil preparation
   (3)  topsoil material and application
                                             191

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                                       Section VIII
                                       GLOSSARY
AASHO classification (soil engineering).—The
   official classification of  soil materials  and
   soil aggregate  mixtures for highway  con-
   struction used by the American Association
   of State Highway Officials.
Abandoned mine.—A mining operation where
   coal is no longer being produced and it is the
   intent of the operator  not  to continue  pro-
   duction from the mine.
Abrasion.—The wearing away by friction, the
   chief agents being currents  of water or wind
   laden with sand and other rock debris,  and
   glaciers.
Access road.—Any haul road or other road  con-
   structed, improved, maintained, or used by
   the operator that ends at the pit or bench, and
   is located within the area of land affected.
Acid-producing  materials  (acid  forming).—
   Rock  strata  containing  significant  pyrite,
   which if exposed by coal mining will, when
   acted upon by air and water, cause acids to
   form.
Acid soil.—Generally, a soil that is acid through-
   out most or all of the parts of it that plant
   roots occupy. Commonly applied to only the
   surface-plowed layer or to some other specific
   layer or horizon of a soil.  Practically,  this
   means  a soil more  acid  than pH  6.6;  pre-
   cisely, a soil with a pH value less  than  7.0.
   A soil having a preponderance  of hydrogen
   over hydroxyl ions in the soil solution.
Acid spoil. —See also Spoil; Toxic spoil. Usually
   spoil  material  containing  sufficient pyrite
   so that weathering produces acid water  and
   the pH of the soil determined by  standard
   methods of soil analysis is  between 4.0  and
   6.9.
Active surface mine operation.  — A mining oper-
   ation where land is being disturbed in prepa-
   ration for and during the removal of a min-
   eral.
Agglomeration.—The uniting  of dispersed  sus-
   pended matter into larger floes or particles
   that settle rapidly.
Aggregation, soil.—The cementing or binding
   together of several soil particles into a  sec-
   ondary unit, aggregate,  or granule. Water-
   stable aggregates, which will not disintegrate
   easily, are of special importance to soil struc-
   ture.
 Agricultural  limestone.—Contains   sufficient
   calcium and magnesium carbonate  to be
   equivalent to not less than 80 percent calcium
   carbonate and must be fine enough so  that
   not less than 90 percent shall pass through a
   U.S. Standard No. 10 sieve and not less than
   35 percent shall pass through a U.S. Standard
   No. 50 sieve.
 Alkaline soil.—Generally, a soil  that is alkaline
   throughout most or all of the parts of it occu-
   pied by plant roots, although the term is
   commonly applied to only a specific layer or
   horizon of a soil.  Precisely, any soil horizon
   having a pH value greater than 7.0. Prac-
   tically, a soil having a pH  above 7.3.
 Amendment.—Any  material,  such  as lime,
   gypsum, sawdust, or synthetic conditioners,
   that is worked into the soil to make it more
   productive. Technically, a fertilizer is also an
   amendment, but the term amendment is used
   most commonly for  added materials other
   than fertilizer.
 Angle of dip.—The  angle an inclined stratum
   makes with the horizontal.
 Annual plant  (annuals).—A plant  that com-
   pletes its life cycle and dies in 1 year or less.
 Area mining. —Surface mining that is carried on
   in level to gentle rolling topography on rela-
   tively large tracts.
 Aspect.—The direction toward  which a slope
   faces. Exposure.
 Available nutrient.—The part of the supply of
   a plant nutrient in the soil that can be taken
   up by plants at rates and in amounts signifi-
   cant to plant growth.
Back blade. —In regrading, to drag the blade of
  a bulldozer or grader in the down position as
  the machine moves backward, as opposed to
  pushing the blade forward.
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Backfill.—The operation of refilling an excava-
   tion. Also the material placed in an excava-
   tion in the process of backfilling.
Basin.—A natural depression of strata contain-
   ing a coal bed or other stratified deposit.
Bedload. —The sediment that moves by sliding,
   rolling, or bouncing on or very near the stream-
   bed. Sediment moved mainly by tractive or
   gravitational forces, or both, but at velocities
   less than the surrounding flow.
Bench.—The surface of an excavated area at
   some point between the material  being mined
   and the original  surface  of the ground on
   which equipment can set, move, or operate.
   A working road or base below a  highwall, as
   in contour stripping for coal.
Berm.—A strip of coal left in place temporarily
   for use in hauling or stripping. A layer of
   large rock or other relatively heavy stable
   material placed at the outside bottom of the
   spoil pile to help hold the pile in position (a toe
   walk). Also used similarly higher in the spoils
   for the same purpose.
Biennial plant.—A plant that requires 2 years
   to complete its life cycle.
Broadcast seeding.—Scattering seed on the sur-
   face of the soil. Contrast  with Drill seeding,
   which places the seed in rows in the soil.
Buffer strip. — 1. Unaffected  areas between the
   mining operation and areas designated for
   other public and private use.
     2. Strips of grass or other erosion-resisting
   vegetation between or below surface or auger
   mining disturbances.
Bunchgrass.—A  grass  that does not  have
   rhizomes or stolons and forms a bunch or tuft.
Calcareous soil.—Soil containing sufficient cal-
   cium carbonate (often with magnesium car-
   bonate)  to effervesce visibly when treated
   with cold 0.1 normal hydrochloric acid.
Canopy.—The cover of leaves and branches
   formed by the tops or crowns of plants.
Channel stabilization.—Erosion prevention and
   stabilization of  velocity  distribution in a
   channel, using jetties,  drops, revetments,
   vegetation, and other measures.
Check dam.—Small dam constructed in a gully
   or other small water course to decrease the
   streamflow velocity, minimize channel scour,
   and promote deposition of sediment.
Chute.—See section I, volume II.
Clay (soils). — 1. A mineral soil separate consist-
   ing of particles less than 0.002 mm in equiva-
   lent diameter.
     2. A soil textural class.
     3. (engineering). A fine-grained soil that has
   a high plasticity index in relation to the liquid
   limits.
Clearing.— The removal of  vegetation, struc-
   tures, or other objects in preparation for earth-
   moving activities.
Climate.—The sum total of  all atmospheric or
   meteorological influences, principally temper-
   ature, moisture, wind, pressure, and evapo-
   ration, that combine to characterize a region
   and give it individuality by influencing the
   nature of its land forms, soils, vegetation, and
   land use. Contrast with Weather.
.Clinker.—Sometimes referred to as scoria,  &
   term commonly used to identify the material
   overlying a burned coal bed. Clinkers usually
   consist of  baked clay, shale,  or  sandstone.
   They weather to gravel-sized  particles  that
   are generally red in color and are used exten-
   sively as a road-surfacing material. Clinkers
   are similar to Red dog.
Clod.—A compact, coherent mass of soil ranging
   in size from 5 to 10 mm (0.2 to 0.4 inches) to
   as  much as 200 to 250 mm (8  to .10 inches);
   produced artificially, usually by the activity
   of  man by  plowage, digging, etc., especially
   when these operations are  performed on  soils
   that are either too wet or too dry for normal
   tillage operations.
Coagulation.—The destabilization and initial
   aggregation of colloidal and finely  divided
   suspended  matter by  the  addition of a  floe-
   forming chemical.
Coal seam.—A layer, vein, or deposit of coal. A
   stratigraphic part of the earth's surface con-
   taining coal.
Coarse texture. —The texture exhibited by sands
   and loamy  sands. A soil containing large
   quantities  of these  textural  classes (U.S.
   usage).
Compaction.—The closing of  the pore  spaces
   among the particles of soil and rock, generally
   caused by running heavy equipment over the
   area as in  the process of  leveling the over-
   burden material of strip mine banks.
Conifer.—A   tree  belonging  to   the  order
   Coniferae,  usually evergreen with cones and
   needle-shaped or  scalelike leaves, and  pro-
   ducing wood known  commercially as soft-
   wood.
Conservation.—The protection, improvement,
   and use of natural resources  according  to
   principles that will assure their highest eco-
   nomic or social benefits.
Contour. —An imaginary line connecting points
   of equal height above sea level as they follow
   the relief of the terrain.
Contour stripping or surface mining. —-The re-
   moval of overburden and mining from a  coal
                                              94

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    seam that outcrops or approaches the surface:
    at approximately the same elevation, in steepj
    or mountainous areas.                      [
 Cool-season plant.—A plant  that makes its'
    major growth during the cool portion of tha
    year, primarily in the  spring, but in somej
    localities in the winter.                     |
 Core drilling.—The process by which a cylindri-!
    cal sample of rock and other strata is obtained'
    through the use of a hollow drilling bit thatj
    cuts and retains a section of the rock or other|
    strata penetrated.                 -        I
 Corrasion. —The wearing away of earth mate-1
    rials through the cutting, scraping,  scratch-)
    ing, and scouring effects of  solid material!
    carried in the currents of water or air.'       j
.Coyer  crop.—A   close-growing  crop  grownj
    primarily for the purpose of protecting and;
    improving soil  between periods of regular)
    crop production or between trees and vines j
    in orchards and vineyards.                  |
 Cover, ground.—Any  vegetation producing a
    protecting mat on or just above the soil sur-
    face. In forestry, low-growing shrubs, vines,
    and herbaceous plants under the trees.
 Cover, vegetative.—All plants of all sizes andj
    species  found  in  an area, irrespective of I
    whether they have forage or other value.      |
 Cover, wildlife.—Plants or objects used by wild)
    animals for nesting, raising of young, escape I
    from predators, or protection from adverse i
    environmental conditions.           ,       j
 Crust;—A dry surface layer on soils that is much i
    more compact,  hard, and brittle  than the
    material immediately beneath it.
 Culvert.—A closed conduit for the free passage j
   of surface drainage water under a roadway or |
   other embankment.                 .       j
 Cut.—Longitudinal excavation made b,y a strip- j
 .  .mining machine to remove overburden in a{
   single progressive line from one side or end ofj
   the property being mined to the other side or
   end.
Cut-and-f ill.—Process of earth moving by exca-
   vating part of an area and using the excayated  )
   material  for adjacent embankments or fill  j
   areas.
 Density,  forage.—The percentage of  ground I
   surface that appears to be completely covered j
   by  vegetation  when viewed directly  from )
   above,
 Density stand.—Density of Stocking expressed !
   in number of trees per acre.
 Deposition.—The  accumulation  of  material
   dropped because of a slackening movement
   of the transporting agent—water or wind.
 Detachment.—The  removal  of  transportable
   fragments of soil material  from a soil mass
   by  an eroding agent, usually falling rain-
   drops, running  water, or  wind. Through
 ,  detachment, soil particles or aggregates are
   made ready for transport—soil erosion.
 Direct  seeding.—A method of establishing a
   stand of vegetation by sowing seed on the
   ground surface.
 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 section I, volume II.
 Diversion swale (ditch).—See section I, volume
   II.
 Dragline.—An excavating machine that utilizes
   a bucket operated and suspended by means
 ,  of lines or cables, one of which hoists or lowers
  , the bucket  from a boom;  the other,  from
   which the name is derived, allows the bucket
   to swing  out  from the  machine  or to  be
  , dragged  toward  the  machine  for  loading.
   Mobility of draglines is by crawler mounting
   or by a walking device for propelling, featur-
   ing pontoonlike feet and a circular base or
   tub.  The swing of the machine is based  on
   rollers and rail. The machine usually operates
  . from the highwall.
 Drainage.—The removal of excess surface water
   or ground water from land by means of sur-
   face or subsurface drains.
 Drill seeding.—Planting  seed  with a drill  in
   relatively narrow rows, generally less than a
   foot apart..Contrast with Broadcast seeding.
 Droughty. —Exhibiting a poor moisture-holding
 •  capacity due to excessively high permeability
   and a low percentage of fines.
 Dugout  pond.—An  excavated pond  as  con-
  . trasted with a pond formed by constructing a
   dam.
Emergency spillway.—A spillway used to carry
   runoff exceeding a given design flood.
Energy dissipators. — See section IV, "Handling
   Disposal of Concentrated Flows."
Environment. —The sum total of all the external
 ,  conditions that may act upon an organism or
   community to influence its development or
   existence.
Erodible (geology and  soils). —Susceptible to
   erosion.
Erosion. —1.  The wearing away of the land sur-
   face 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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     The following terms are used to describe dif-
     ferent types of water erosion:

     Accelerated  erosion:  Erosion  much  more
       rapid than normal,  natural, or  geologic
       erosion, primarily as a result of the influ-
       ence  of the activities of man or,  in some
       cases, of other animals or natural- catas-
       trophies that  expose base-surfaces, for
       example, fires.
     Geological erosion:  The normal or natural
       erosion  caused by geological  processes
       acting  over long  geologic -periods  and
       resulting in the wearing away of mountains,
       the  building  up  of  floodplains,  coastal
       plains, etc. Syn: Natural erosion.
    Gully erosion: The erosion process whereby
       water accumulates in  narrow  channels,
       over  short periods, and removes  the soil
       from  this  narrow . area to  considerable
       depths, ranging from 1 to 2 feet to as much
       as 75  to 100 feet.
    Natural  erosion: Wearing away of the earth's
      surface by  water,  ice,  or other  natural
      agents under natural environmental  con-
      ditions of climate, vegetation, etc., undis-
      turbed by man. Syn.: Geological erosion.
    Normal  erosion: The gradual  erpsion of land
      used by man which does not greatly exceed
     ^ natural erosion. See Natural erosion.
    Rill erosion:  An  erosion process  in which
      numerous  small  channels, only  several
      inches deep are formed. Occurs mainly on
      recently cultivated soils.          ,
    Sheet erosion: The removal of a fairly uni-
      form layer of soil from the land surface by
      runoff water.
   Splash erosion: The spattering of small  soil
     particles caused by the impact of raindrops
     on wet soils. The loosened  and spattered
     particles may or may not be removed sub-
     sequently by surface runoff.
Erosive.—Refers to wind or water haying suffi-
   cient velocity to  cause erosion. Not to be
   confused  with Erodible as a quality of soil.
Esthetic.—Of beauty; beautiful.
Evapotranspiration.—A collective term mean-
   ing the loss of water to the atmosphere from
   both evaporation and transpiration  by vege-
   tation.
Excelsior blanket.—See section II, volume  II.


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 physi-
   cal conditio'n of the soil are favorable.
   Fertilizer. — Any natural or manufactured mate-
     rial added to the soil in order to supply one or
     more plant nutrients.
   Fertilizer  grade.—The  guaranteed minimum
     analysis in whole numbers, in percent, of the
     major plant nutrient elements contained in a
     fertilizer material or in a mixed fertilizer. For
     example, a fertilizer with a grade of 20-10-5
     contains 20 percent nitrogen (N), 10 percent
     available phosphoric acid (P2OS), and 5  per-
     cent water-soluble  potash  (K2O). Minor ele-
     ments may also be included. Recent trends
  'are to express the percentages in  terms of
,  '   the elemental fertilizer nitrogen (N), phos-
   '  phorus (P), and potassium (K).  .  .
  Fertilizer requirement. — The quantity of certain
   . plant nutrient elements needed,  in addition
    to the amount supplied by the soil, to increase
   _ plant growth to a designated optimum.
  Fibrous  root system.—A plant root  system
    having a large number of small, finely divided,
    widely spreading roots but no large individual
   _ roots. Usually a characteristic of most grasses.
  Field capacity (field moisture capacity).—The
    amount of soil water remaining in a soil after
    the free water has been  allowed to  drain away
    for a day or two if the root  zone has been
   previously saturated. It  is  the greatest
   amount of water  that the soil will  hold under
;   conditions of free drainage, usually expressed
   as a percentage of the oven-dry weight of soil
   'or other convenient unit.
 Filter  (sediment).—See section  V,  "Sediment
;   Traps."
 Filter strip.—Strip  of  vegetation that retards
   flow of runoff water, causing deposition of
   transported material, thereby  reducing sedi-
   ment flow.                         .  . '
 Final cut.—Last cut or line of excavation made
   on a specific property or  area.
 Flocculation. —The process by which  suspended
   colloidal or very fine particles  are  assembled
,   into  larger masses or floccules, which.even-
   tually settle out of suspension.      .
 Flume.—See section I, volume II.
 Fly ash.—All solids, ash, cinders, dust, soot, or
   other partially incinerated matter that is car-
   ried in or removed from a gas stream. Fly ash
   is usually associated  with electric generating
   plants.
Forage. —Unharvested plant material that can
   be used  as feed by domestic animals. Forage
i   may be grazed or cut for hay.          ,.
 Gabion.—A  mesh container used  to  confine
   rocks or stones and used to construct dams
   and groins to line stream channels.
                                             96

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 Geology.—The science that deals with the his-
    tory of the earth and its life as  recorded in
    rocks.
 Georgia V-ditch. —Grading is performed to
    create positively draining swales  midpoint
    between the parallel to the high wall and long-
    wall to convey water runoff to drains estab-
    lished to carry the water away from the spoil'
    area.                                     |
 Germination. — Sprouting; beginning of growth.
 Grade. — 1. The slope of a road, channel, or natu-
    ral ground.                       '        I
      2.  The finished  surface of a  canal  bed, I
    roadbed, top of embankment, or bottom of!
    excavation; any surface prepared for the (sup- i
    port of construction, like paving  or laying a!
    conduit.                                   I
      3. To finish the surface of a 'canal bed, road- i
    bed, top of embankment,  or bottom of exca-1
    vation. '              '          ..','",.!
 Grade stabilization structure.—A structure for !
    the purpose of stabilizing the grade of a gully I
    or other watercourse,  thereby preventing j
   further headcutting or lowering of the channel j
 •  grade.                                     i
 Grassed waterways.—See section I,  volume II. !
 Green manure crop.—Any crop  grown for the
   purpose of being turned under while green, or
   soon after maturity for soil improvement..     !
 Ground water. —Subsurface water  occupying I
   the saturation  zone, from which wells  and 1
   springs are  fed. In a strict sense the, term j
   applies only to water below the water'table., i
   Also called plerotic water, phreatic water.     '
 Grouted.—Having the area  between pieces of i
   rock, brick,  etc., filled with mortar or con- j
   crete.                            ;        \
 Growing season.—The season that, in general,
   is warm enough for the growth of plants, the
   extreme average limits  of  duration being
   from the average date of the last killing frost J
   in spring to that of the first killing ffo'st in j
 •  autumn. On  the whole, however, the growing
   season  is confined to that period of  the year
   when the daily means are above 42° F.   ..  ,,
Grubbing.—The operation of removing stumps
   and roots.                '           '
Habitat.—The  environment in which the life I
  needs of a plant or animal are supplied.        '
Hardpan.—A hardened soil layer in the lower A j
  or in the B horizon caused by cementation of I
  soil  particles with organic matter  or  with j
  materials such  as silica,  sesquioxides,  or, i
  calcium carbonate. The hardness does  not
  change appreciably with changes in moisture
    content, and pieces of the hard layer do not
    slake in water.  .  ..
 Haul road. —Road  from pit to loading dock,
    tipple, ramp, or  preparation plant used for
    transporting mined material by truck.
 Head of the hollow (also valley fill method).—
    Basically, overburden material from adjacent
    contour or mountain top mines is placed in
    compacted  layers  in  narrow,  steep-sided
    hollows so tlv.'i, surface drainage is possible.
^Heaving.—The partial lifting of plants out of
' •:   the ground, 'frequently breaking their roots,
   ,as a result of freezing and thawing of the sur-
 .   face soil during the winter.
 High wall.—The unexcavated  face of exposed
    overburden and coal in a surface mine or the
  '  face or bank on the  uphill side of a contour
  'strip mine excavation.
 Hydrology.—The  science  that relates to  the
 "•• water systems of the earth.
 Hydroseeding.—Dissemination of seed hydrau-
   lically in a water medium. Mulch, lime, and
 -  fertilizer can be incorporated into the sprayed
  * mixture. •
 Impervious soil.—A soil through which water,
 >  air,- or roots cannot  penetrate. No soil  is
 '  impervious to water and air all the time.
 Impoundment.—A reservoir  for collection  of
   water. Collection of water  by damming a
 ; ••• stream or 'the like.  Used in connection with
 -' the storage of tailings from a mine.
 Infiltration.—The flow of a liquid into a sub-
   stance through pores or  other openings,
  • connoting flow into a soil in contradistinction
   to percolation, which connotes flow through a
   porous substance.
 Inlet.—The  upstream end of any structure
   through which water may flow.
 Inoculation.—The process of adding cultures  of
   symbiotic micro-organisms  to legume seed
   to enhance atmospheric nitrogen fixation.
 Interceptor  dike (straw  bale).—See Diversion
   dike, section I, volume II.
 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.
Land use planning.—The development of plans
  for the uses of land that, over long periods,
  will best serve the general welfare, together
  .with the formulation of ways and means for
  achieving such uses.
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 Landslide.—The failure of a slope in which the
    movement of the mass takes place along in-
    terior surfaces of sliding.
 Leaching.—The removal of materials in solution
    by the passage of water through soil.
 Legume.—A member of the legume or pulse
    family, Leguminosae. One of the most impor-
    tant and widely distributed plant families.
    The fruit is a legume, or pod that opens
    along two sutures when ripe. Flowers are usu-
    ally papilionaceous  (butterflylike).  Leaves
    are alternate, have stipules, and are usually
    compound. Includes many valuable food and
    forage species, such as the peas, beans, pea-
   nuts, clovers, alfalfas, sweet  clovers, les-
   pedezas, vetches, and kudzu. Practically all
   legumes are nitrogen-fixing plants.
 Level spreader.—See section I, volume II.
 Lime.—Lime, from the strictly chemical stand-
   point, refers to only one compound, calcium
   oxide (CaO);  however, the term lime is com-
   monly used in agriculture  to include a great
   variety  of materials that are usually com-
   posed of the  oxide, hydroxide, or carbonate
   of calcium or of calcium and magnesium. The
   most commonly  used forms of agricultural
   lime are ground  limestone (carbonates), hy-
   drated lime (hydroxides), burnt lime (oxides),
   marl, and oyster shells.
 Lime requirement.—The amount of standard
   ground limestone required to bring a 6.6-inch
   layer of an acre (about 2 million pounds of
   mineral  soils) of acid soil to some specific
   lesser degree of  acidity, usually to slightly
   or very  slightly  acid. In common practice,
   lime requirements are given in tons per acre
   of pure limestone,  ground finely enough so
   that all of it passes a  10-mesh screen arid at
   least half of it passes a 100-mesh screen.
 Limestone.—A sedimentary rock composed of
   calcium  carbonate, CaCO3. There are many
   impure varieties.
Litter.—Freshly fallen or slightly decomposed
   organic debris.
Loess.—Material deposited by wind and con-
   sisting of predominantly silt-sized particles.
Log-and-pole structure.—See section V, "Types
   of Control."
Microclimate.—A local climatic condition near
   the ground  resulting from  modification of
   relief, exposure, or cover.
Micro-organism.—Any  living  thing  that is
   microscopic or submicroscopic in size.
Mined land.—Land  with new  surface charac-
   teristics due to the  removal of  mineable
    commodity by surface mining methods and
    subsequent surface reclamation.
 Mountain top removal. — In this mining method,
    100 percent of the overburden covering a coal
    seam is removed in order to recover, 100 per-
    cent of the mineral. Excess spoil material is
    hauled to a nearby hollow to create a valley
    fill.
 Mulch.—Natural  or artificial material used  to
    provide more desirable moisture and tempera-
    ture relationships for plant growth.  It is also
    used to control unwanted vegetation.
 Natural drainway. —Any water course that has
   a clearly  defined  channel, including inter-
   mittent streams.
 Neutralization.—When  associated  with coal
   mining, neutralization is the addition of an
   alkaline material such as lime or limestone to
   an acid material to raise the pH and over-
   come an acid condition.
 Nitrogen fixation.—The conversion of atmos-
   pheric (free) nitrogen to nitrogen compounds.
   In soils the assimilation of free nitrogen from
   the air by soil organisms (making the nitro-
   gen eventually available to plants). Nitrogen
   fixing organisms associated with plants such
   as the legumes  are called symbiotic; those
   not  definitely associated  with  plants  are
   called nonsymbiotic.
Nutrients.—Any element taken into  a plant
   that is essential to its growth.
 Operation.—All of the premises, facilities, rail-
   road loops, roads, and equipment used in the
   process of extracting and removing a mineral
   commodity from a designated surface mine
   or in the determination of the location, qual-
   ity, and quantity of a natural mineral deposit.
 Organic matter.—The 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.
 Orphan lands.—Disturbed  surfaces  resulting
   from surface mines that were inadequately
   reclaimed  by the operator and for which he
   no longer has any fixed responsibility. Usu-
   ally refers  to lands mined previous  to  the
   passage of comprehensive reclamation laws.
Outfall.—The point where water flows from a
   conduit, streanr, or drain.
Outslope.—The  exposed  area  sloping  away
   from a bench cut section.
Overburden.—The earth, rock, and other mate-
   rials that lie above the coal.
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 Perennial plant.—A plant that normally lives
    for 3 or more years.
 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 hori-
    zon'even though the others are permeable.
 pH. —A numerical .measure of the hydrogen ion
    concentration. It is used to indicate acidity
    and alkalinity. The:neutral point is pH 7.0;
    pH values below 7.0 indicate acid conditions
    and those above 7.0 indicate alkaline condi-
    tions.      .
 Piping.—Removal of soil material through sub-
    surface flow channels or "pipes" developed
    by seepage water.
 Pit.—Used in reference to a specifically describ-
    able area of open-cut mining. May be used to
    refer to only that part of'the open-cut mining
    area front which coal is being actively  re-
    moved or may refer to the entire contiguous
    mined area.
 Pitch.—See Angle of dip.    :>
 Plant nutrients.^-The elements or groups of
    elements taken in by-a plant that are essential
    to its  growth and used -itv elaboration of its
    food arid tissues. Includes nutrients obtained
,    from fertilizer ingredients.
 Planting  season.—The period of the year when
   planting or transplanting is considered advis-
   able from the standpoint of successful estab-
   lishment.
 Pollution.—Environmental degradation result-
   ing from man's activities or natural events.
 Pond.—A body  of water of limited size either
   naturally or artificially confined and usually
   smaller than a lake.
 Preplanning.—Process of foreseeing  reclama-
   tion  problems and determining measures to
   minimize offsite damages during the  mining
   operation and to provide fe>r quick stabiliza-
   tion of  the mining.        !. -
 Puddled soil.—A dense soil/dominated by mas-
 1  sive  or single-grain structure, almost imper-
   vious to air and water. This condition results
 '  from handling a soil when it is in a wet plastic
   condition so  that when it  dries it becomes
   hard and cloddy.         :
"Pyrite.—A  yellowish  mineral,  iron disulfide,
   FeS2,  generally metallic': appearing.  Also
   known  as fool's gold.      :
 -     .  .-•'•..       '  .  ;  -; >  - - .        • '
Rain. —1. Heavy: Rain that is falling at the time
   of observation with an intensity in excess of
   0.30 inch per .hour (over. Q<03 inch in 6 min-
   utes).             .....''. -r
      2. Light: Rain that is falling at the time of
    observation with an intensity of between  a
    trace and 0.10 inch per hour (O.Ol inch in  6
    minutes).      •:        *    '."
      3. Moderate:  Rain that is falling at the
    time of  observation  with an intensity of
    between  0.11 inch per hour (0.01+ inch in  6
    'minutes),and 0.30 inch per hour (0.03 inch in
    6 minutes).
 Reclamation^—The  process  of reconverting
    mined land to, its former  or other productive
  •  uses,
 Red dog.--A gob pile after it has burned. The
    material is generally used as a road-surfacing
    material; it has no harmful acid or alkaline
    reaction.                     .
 Reforestation.—The  natural or artificial  re-
    stocking of an area with forest trees.
 Regrading.—The movement of earth  over a
 	surface or depression to change the shape of
    the land surface. .
 Rehabilitation.—Implies that the land will be
    returned to a form and productivity in con-
    formity with a prior land use plan, including
    a stable ecological state  that does not con-
    tribute, substantially to  environmental  de-
    terioration and is consistent with surrounding
    esthetic values. •   ,
 Retention.—The amount of precipitation on a
    drainage area that does not escape as runoff.
  /It is:the difference between the total precipi-
    tation and total runoff.
 Revegetation.—Plants or growth that replaces
   original ground cover following land disturb-
   ance.
 Reverse terrace. —See Georgia V-ditch.
 Revetment.—A facing of stone or other material,
   either permanent  or temporary, placed along
   the edge of a stream to stabilize the bank arid
   protect  it from the erosive action  of the
   stream.
 Rhizome.—A  horizontal  underground  stern,
   usually  sending out roots and abovegrourid
   shoots at the nodes.                .   . .
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 ap-
  plied to brush or  pole mattresses, or brush
  and stone, or other similar materials used for
  soil erosion control.
Rock-fill dam.—A dam composed of loose  rock
 ^usually dumped in place, often with the up-
 , stream part constructed of handpacked  or
  derrick-placed  rock and  faced with  rolled
  earth or with an impervious surface of con-'
  crete, timber, or steel.             ,
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 Runoff.—That portion of the precipitation on
   a drainage area that is discharged from the
   area in stream channels. Types include sur-
   face runoff, ground water runoff, or seepage.
 Sand.—A  soil  particle between  0.074 (#200
   Sieve)  and 4.76  (#4 sieve) millimeters in
   diameter.
 Sandstone.—A  cemented  or  otherwise com-
   pacted detrital sediment composed predomi-
   nantly of quartz grains, the  grades of  the
   latter being those of sand.
 Scalping.—Removal of vegetation before min-
   ing.
 Scarify.—To loosen or stir  the  surface  soil
   without turning it over.  Also, in the case of
   legume  seeds, abrasion of  the hard coat to
   decrease time required for germination.
 Scheduling.—Chronological ordering of various
   stages of surface mining operations to mini-
   mize time and duration of exposure.
 Scour.—The wearing away of terrace or diver-
   sion channels or streambeds.
 Seam. —A stratum or bed of coal.
 Sediment.—Solid material, both mineral and
   organic, that is in suspension, is being trans-
   ported,  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.
 Sediment basin.—See section I, volume II.
 Sediment trap.—See section I, volume II.
 Sediment yield.—The total amount of sediment
   that passes any section of a stream.
 Seedbed. —The soil prepared by natural or arti-
   ficial means to promote  the germination of
   seed and the growth of seedlings.
 Seep.—A more or less poorly defined area where
   water oozes from the earth  in small quanti-
   ties.
 Selected earth material.—Suitable native mate-
   rial obtained  from roadway cuts or borrow
   areas, or other similar  material,  used  for
   subbase, roadbed material, shoulder sur-
   facing, slope cover, or other specific purposes.
Semiarid,—A term  applied to regions or  cli-
   mates where  moisture is normally  greater
   than under arid conditions but still definitely
   limiting to the  growth of most crops. Dry-
   land farming methods or  irrigation generally
   is required for  crop  production. The upper
   limit  of  average annual precipitation in the
   cool semiarid  regions is as low as 38 cm  (15
   inches),  whereas in  tropical regions it is as
   high as 114 to  127 cm (45 or 50 inches).
Shale.—Sedimentary or stratified rock struc-
   ture generally formed by the consolidation of
   clay or claylike material.
 Sheet flow.—Water, usually storm runoff, flow-
   ing in a thin layer over the ground surface.
   Syn.: overland flow.
 Side slopes.—The slope of the sides of a canal,
  - dam,  or embankment.  It is  customary to
   name the horizontal distance  first  as 1.5 to
   1.0, or frequently IVfe: 1, meaning a horizontal
   distance of 1.5 feet to 1 foot vertical.
 Silage.—A crop that has been preserved in a
   moist  succulent  condition by  partial  fer-
   mentation.  Chief  silage  crops are corn,
   sorghums, and various legumes  and grasses.
 Silt. — Small mineral soil grains, the particles of
   which  range in diameter from 0.05 to 0.002
   mm (or 0.02-0.002 mm  in the international
   system).
 Slope characteristics. —Slopes may be charac-
   terized as concave (decrease in  steepness in
   lower portion), uniform, or convex  (increase
   in steepness at base). Erosion is  strongly
   affected by shape, ranked in order of increas-
   ing erodibility from concave  to uniform to
   convex.
 Slope stability.—The resistance of any inclined
   surface, as the wall of an open pit or  cut, to
   failure by sliding or collapsing.
 Sludge.—The precipitate resulting from chemi-
   cal treatment of water, coagulation, or sedi-
   mentation.
 Sod.—A  closely knit  ground cover  growth,
  primarily of grasses.
 Soil. —1.  The unconsolidated mineral and  or-
  ganic 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 sub-
  jected  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  characteris-
  tics.
     3. A kind of soil; that 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.
Soil   conservation. — Protection   of  the  soil
  against physical loss  by erosion or against
  chemical deterioration; that is,  excessive loss
  of  fertility by  either  natural or  artificial
  means.
Soil series.—The basic unit of soil classification
  being a subdivision of a family and consisting
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   of soils that are essentially alike in all majorj
   profile characteristics except the  texture  of
   the A horizon.                             '
 Soil  structure.—The  combination or  arrange-
   ment of primary soil particles into secondary,
   particles, units, or peds.                    i
 Soil survey.—A general term for the systematic'
   examination of soils in the field and in labora-j
   tories; their, description and classification;'
   the mapping of kinds of soil;  the interpreta-:
   tion of soils according to  their adaptability
   for various crops, grasses, and trees;  their
   behavior under  use or treatment for plant!
   production or for other purposes.            I
 Soil texture. — Soil texture class names of soils!
   are based upon the relative percentages of;
   sand, silt, and clay.
 Spoil.—See also  Acid spoil;  Toxic spoil. The
   overburden or noncoal  material removed in[
   gaining access to the coal or mineral material i
   in surface mining.                          !
 Spoil bank (spoil pile).—Area created by thej
   deposited spoil or overburden material prior'
   to backfilling. Also called cast overburden.
 Sprigging. —The  planting of  a portion of thei
   stem and/or root of grass.                .   j
 Stabilize.—Settle,  fix .in place,  make  non-!
   moving, usually accomplished on overburden)
 .  ,by planting trees, shrubs,  or  grasses, or by|
   mechanical compaction or^aging.            \
 Staging.—Arrangement of major mining opera-j
   tions, such as  clearing,  grubbing, and scalp-1
   ing, into small discrete segments so that at j
   any one time the various phases of clearing,!
   extraction,  and reclamation can be carried on |
   simultaneously.                            I
 Stand. — 1.  An aggregation of trees  or  other j
   growth occupying a specific area and suffi-j
   ciently uniform in composition (species), age
   arrangement, and condition to be distinguish-
   able  from  the forest  or; other growth on j
 .  adjoining areas.                            |
     2.  The number of plants per unit of area
   other than trees.   ,•    .   .  ;
 Stolon. — A  horizontal stem that grows along
   the surface  of the soil and roots at the nodes. I
 Stratified. — Composed of, or arranged in, strata !
   or layers, as stratified alluvium. The,term is }
 ,  applied to geological materials. Those layers i
   in soils that are produced,by the processes of j
   soil formation are called horizons, while those I
   inherited from parent  material are called
 .L  strata,.      ,          ,  •  ,         .   .    j
Strip  mine. —Refers to a procedure of mining j
 ,  that entails the complete removal of all mate- i
   rial from  over  the product  to be mined in a j
   series of rows  or strips; also referred to as '\
   open cut, open pit, or surface mine. .          \
 Subsoil.—The B horizon of soils with distinct
   profiles.  In soils with weak profile develop-
  , ment, the  subsoil can be defined as the soil
   below the plowed soil (or its equivalent of sur-
   face soil) in which roots normally  grow. Al-
   though a common term, it cannot be defined
   accurately. It  has .been  carried over  from
   early days when soil was  conceived only as
   the plowed soil and that under it as subsoil.
 Surface mining.—Mining method whereby the
   overlying materials  are removed  to  expose
   the mineral for extraction.
 Surface soil.—That  part  of  the  upper  soil of
   arable  soils  commonly stirred  by  tillage
   implements or  an equivalent depth (5 to 8
   inches) in npnarable soils.
 Surface water.—Water, from whatever source,
   that is flowing on the surface of the ground.
 Suspended  solids. — Sediment that is in suspen-
   sion in water but,that will physically settle
   out under. quiescent conditions  (as differenti-
   ated from dissolved material).
 Swale.—A hollow or depression.
 Syncline.—A  fold of rock beds that is convex
   downward.          .    ,
 Tacking  (mulch). —The  process  of  binding
   mulch fibers together by the addition of a
   sprayed chemical compound.
 Terrace.—An embankment or combination of an
   embankment and channel constructed across
   a slope to control erosion by diverting. .
 Terrace outlet channel. —Channel,  usually hav-
   ing a vegetative cover, into which the flow
   from one or more terraces is discharged and
   conveyed from the field.
 Terrace types.—  Absorptive:  A ridge type of
   terrace used primarily for moisture conserva-
   tion.                   .•• •:'•;.-.:-.•
     Bench: A terrace approximately on the
   contour,  having a steep or  vertical drop to
 ',••• the slope below, and having a horizontal or
 .gentle sloping part. It-is adapted to steeper
   slopes.               •   •
     Drainage:  A broad,  channel-type terrace
   used primarily to conduct water from the area
   at a low velocity. It is adapted to less absorp-
   tive soil and regions of high rainfall.   '
 Texture.—The  character,  arrangement,  and
   mode of  aggregation  of particles that  make
,;,  up the earth's surface.           -
 Tillage equipment (tools). —Field tools and ma-
   chinery that are designed to lift, invert, stir,
.  or pack soil, reduce size of clods and uproot
   weeds; i.e., plows, harrows, discs, and culti-
   vators.
                                             101

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 Toe.—The point of contact between the base of
   an embankment or spoil bank and the founda-
   tion surface. Usually the outer portion of the
   spoil  bank where it contacts the original
   ground surface.
 Tolerant.—Capable of  growth  and  survival
   under competitive growing conditions.
 Topographic map.—A map  indicating surface
   elevations and slopes.
 Topography (lay-of-the-land).—The configura-
   tion of the earth's surface,  including  the
   shape and position of its natural and man-
   made features.
 Topsoil.—The unconsolidated earthy  material
   that exists in its natural state above the rock
   strata and that is or can be made favorable
   to the growth of desirable vegetation.
 Toxic spoil.—See also Acid spoil; Spoil. In-
   cludes acid spoil with pH below 4.0. Also
   refers to spoil having amounts  of minerals
   such  as  aluminum, manganese, and iron
   that adversely affect plant-growth.
 Tracking.—The  movement of bulldozers  and
   other  cleated equipment up and down the
   face of a slope for the purposes of stabiliza-
   tion, compaction, erosion control, and vege-
   tative establishment.
Transplant  (forestry).—A  seeding that  has
   been transplanted one or more times in the
   nursery.
Unconsolidated  (soil  material). —Soil material
  in a form of loose aggregation.
Vegetation.—General term including grasses,
   legumes, shrubs, and trees, naturally occur-
   ring and planted intentionally.
Vegetative buffer.—See Buffer strip.
Vegetative cover.—The entire  vegetative can-
   opy on an area.
Voids.—A general term for pore spaces or other
   openings in rock. In  addition to pore space,
   the term includes vesicles, solution cavities,
   or any openings, either primary or secondary.
   Syn.: interstices.
 Volunteer. —Springing  up  spontaneously  or
   without being planted; a volunteer plant.
 Warm season  plant.—A plant  that completes
   most  of its growth during the warm portion
   of the year, generally late spring and summer.
 Water bar.—Any device or structure placed in
   or upon a haul or access road for the purpose
   of channeling or diverting the flow of water
   off the road.
 Water  conservation.—The  physical  control,
   protection, management, and use of water
   resources in such a way as to maintain crop,
   grazing, and forest lands, vegetal cover, wild-
   life, and wildlife habitat for  maximum sus-
   tained benefits  to people, agriculture, indus-
   try, commerce, and other  segments  of the
   national economy.
 Water control (soil and water conservation).—
   The physical control of water by such meas-
   ures as  conservation  practices on the land,
   channel  improvements, and  installation  of
   structures for  water  retardation and sedi-
   ment detention. Does not refer to legal con-
   trol or water rights as defined.
 Water table.—The upper limit of the part of the
   soil or underlying rock material that is wholly
   saturated with  water. The locus of points  in
   soil water at which the hydraulic pressure is
   equal to atmospheric pressure.
 Watersheds.—Total land area above  a given
   point on a stream or waterway that contrib-
   utes runoff to that point.
 Weathering.—Action of the weather elements
   in altering the color, texture, composition, or
   form of exposed objects.
Wind erosion.—The detachment and transpor-
   tation of soil by wind.
Zeta potential.—A measure of the electrokinetic
  charge  (in  millivolts) that  surrounds sus-
  pended particulate matter.
                                             102
        *U.S. GOVERNMENT PRINTING OFFICE: 1991.5its.187/ito5S8

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