METHODS FOR IDENTIFYING AND
EVALUATING THE NATURE AND
EXTENT OF NON-POINT SOURCES
OF POLLUTANTS
U.S. ENVIRONMENTAL PROTECTION AGENCY
Washington, D.C. 2O460
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FOREWORD
This report is issued under Section 304(e)(1)(A,B,C) of
Public Law 92-500. This Section provides:
"The Administrator, after consultation with
appropriate Federal and state agencies and other
interested persons, shall issue to appropriate
Federal agencies, the States, water pollution
control agencies, and agencies designated under
Section 208 of this Act, within one year after the
effective date of this subsection (and from time to
time thereafter) ...information including
guidelines for identifying and evaluating the
nature and extent of non-point sources of
pollutants resulting from —
(A) agricultural and silvicultural activities,
including runoff from fields and crop and forest
lands;
(B) mining activities, including runoff and
siltation from new, currently operating, and
abandoned surface and underground mines;
(C) all construction activity, including runoff
from the facilities resulting from such
construction ?
N
• • • •
This report, prepared under contract by Midwest
Research Institute, Kansas City, Missouri, and Hittman
Associates, Inc., Columbia, Maryland, for the Environmental
Protection Agency, provides general information on methods
of identifying and evaluating sources of pollutants
associated with agricultural, silvicultural, mining and
construction activities. It is intended to enable planners
responsibile for developing regional water quality
management plans to indent!fy and evaluate sources of
pollutants and their effects on water quality in relevant
planning areas. The application of the methods described
must be ascertained on a case-by-case basis as regional
differences can substantialIv-affect the results obtained.
Tr
inistrator
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EPA-430/9-73-014
OCTOBER 1973
METHODS FOR IDENTIFYING AND EVALUATING THE NATURE AND
EXTENT OF NONPOINT SOURCES OF POLLUTANTS
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF AIR AND WATER PROGRAMS
WASHINGTON, D.C.
$
Offlc*
For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402- Price $2.45
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TABLE OF CONTENTS
ae«
1.0 Introduction . . .
2.0 Summary Discussion
2.1 Introduction 3
2.2 The Nature of Nonpoint Pollution from Agriculture,
Silviculture, Mining, and Construction 3
2.3 Models for Predicting Nonpoint Pollution 18
2.4 Sources of Information Relevant to Assessment of
Nonpoint Pollution -j^. .... 24
>**-
References 31
3.0 Agriculture 35
3.1 Introduction 35
3.2 Sources of Pollution from Agriculture . 35
3.3 Pollutant Transport 37
3.4 Extent of Pollution from Agriculture 39
3.5 Prediction of the Nature and Extent of Nonpoint
Pollution from Agriculture 45
References ..... 82
4.0 Silviculture 93
4.1 Introduction 93
4.2 Silvicultural Activities 94
4.3 Nature and Extent of Sources of Pollution from
Silvicultural Activities 100
4.4 Prediction of Pollution from Silvicultural
Activities 132
References 152
5.0 Mining 163
5.1 Introduction 163
5.2 Nature and Extent of Pollution from Mining
Activities 163
-••-.* «
11
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TABLE OF CONTENTS, (Concluded)
5.3 Data Interpretation Aids and Prediction Methods
Pertaining to Pollution Sources from Mining . . . 195
References 226
6.0 Construction 233
6.1 Introduction 233
6.2 Types of Construction Activity 233
6.3 Sources of Water Pollution 234
6.4 Types of Pollutants 239
6.5 Methods of Pollutant Transport 244
6.6 Quantification of Pollution from Construction
Activities 246
References 255
7.0 Acknowledgements 261
iii
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LIST OF FIGURES
Figure No. Title
2-1 A Hypothetical Hydrograph 21
2-2 Hypothetical Hydrographs Showing Effects of
Various Storm Types 22
3-1 Typical Amounts of DDT (ppm) in the Environment. . 41
3-2 Curves Showing the Relationship of Splash of
Soil (E) to Infiltration Capacity for Four
Soil Types 49
3-3 Nomograph for Probable Soil Loss Using Musgrave
Equation 50
3-4 Soil Erodibility Nomograph 53
3-5 Slope--Effect Chart (Topographic Factor, LS) ... 54
3-6 Slope—Effect Chart (Topographic Factor, LS) for
Slopes and Lengths Exceeding Those in Figure 3-5 55
3-7 Sediment Delivery Ratio vs Size of Drainage Area . 59
3-8 Nomograph Solution of Equation 3-14 62
3-9 Sediment Discharge Rating Curves for San Juan
River at Bluff, Utah 63
3-10 Seasonal Flow-Duration Curves for San Juan
River at Bluff, Utah 64
3-11 Sediment Yield vs Drainage Area for the Southwest. 67
3-12 San Ramon Creek at Walnut Creek, California,
Relationship Between Discharge and Suspended
Sediment Concentration 68
3-13 Walla Walla River Near Touchet, Washington, Rela-
tionship Between Discharge and Suspended Sedi-
ment Concentration (Generalized) 69
3-14 Depth-Density Relation of Reservoir Sediment ... 74
3-15 Sediment Load Variations in Lake Mead During
1955-1964 77
3-16 Simplified Runoff Hydrograph and Sediment Load
from Small Agricultural Watersheds 81
4-1 The Distribution and Fate of Chemicals in the
Environment 119
4-2 Lateral Movement of Spray Particles of Various
Diameters Falling at Terminal Velocity in a
8 km/hr (5 mph) Crosswind 121
4-3 Relative Mobilities of Pesticides in Sub-
irrigated Columns of Soil 123
4-4 A Nutrient Cycle for a Forest 129
iv
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LIST OF FIGURES (Concluded)
Figure No. Title
4-5 Textural Triangle of Soils 138
4-6 Average Net Solar Radiation Absorbed by Streams
Between Latitudes 30N and SON on Clear Days
During Several Periods of Exposure to Dif-
ferent Solar Paths 148
5-1 Nomogram 1 197
5-2 Nomograra II 198
5-3 Predicted Slope Distance Covered with Spoil
Below Outcrop for Various Highwall Heights. . . 219
5-4 Predicted Slope Distance Excavated Above Outcrop
for Various Highwall Heights 220
5-5 Typical Cross-Section of Contour Strip Mine . . . 221
v
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LIST OF TABLES
Table Title
2-1 Land Use Data 4
2-2 Representative Rates of Erosion From Various Land Uses ... 6
2-3 Relative Erosion From Various Land Uses: Nationwide .... 7
2-4 Public Agencies as Sources of Data for Identifying and
Evaluating Nonpoint Source Pollution , . . . 25
3-1 Summary of Sediment Prediction Methods „ 47
3-2 Bed Load Correction Table 65
3-3 Classification of Sediment Yield for Pacific Southwest ... 70
3-4 Sediment Yield Levels and Their Ratings for a Watershed of
39 km2 (15 mile2) in Western Colorado „ 72
3-5 Unit Weight of Sediment in Sediment Volume Computations. . . 75
3-6 Unit Weight of Sediment in Sediment Volume Computations. . . 76
4-1 Frequency of Forest Fires Necessary to Maintain Species
for Unmanaged Forests 99
4-2 Percentage of Soil in Logged Area Made Bare by Various
Logging Systems in Washington and Oregon 106
4-3 Causes of Wildfires 109
4-4 Pest Control Accomplishments in the United States, 1969. . . 116
4-5 Cover Factors for Woodland 134
5-1 Mine Drainage Classes. 168
5-2 Underground Mines in Urban Areas 174
5-3 Pennsylvania Bituminous Mining Drainage Cases 180
5-4 Selected Information for Acid Mine Drainage Sources in
Northern Appalachia 183
5-5 Abandoned and Inactive Underground Mines in the U.S. as of
1966 187
5-6 Land Disturbed by Strip and Surface Mining in the U.S. as of
January 1, 1965, by Commodity and State . 188
5-7 Rating of Environmental Effects of Discrete Coal Surface
Mining and Reclamation Operations 192
5-8 Estimated Environmental Effects of Coal Surface Mining . . . 194
5-9 Factors for Converting Concentration Data into Forms for
Checking Anion-Cation Balance 203
vi
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SUMMARY
Agricultural, silvicultural, construction and mining activities
contribute several pollutant substances to surface and groundwaters,
and thus share with other activities the responsibility for protecting
the quality of this country's water resources. These sources are diffuse
in nature and discharge polluting substances to the water via widely
dispersed pathways. Procedures for ameliorating the pollution must
accordingly deal with activities and materials which are spread over
relatively large land areas.
The major pollutant is sediment, the soil materials which erode
from the surface of the land and are transported to streams and reservoirs
by runoff water. Cropland is the chief source of sediment on a total mass
basis; 507o or more of the sediment deposited in streams and lakes is
credited to agriculture. Construction and surface mining activities,
however, yield large quantities of sediment in relatively small regions
of impact; sediment from these sources can have a highly adverse impact
on both the quality of water, and on costs of water supply and storm water
management. Well managed forests are exceptionally free of erosion and
sediment pollution, but soils in forests disturbed by natural disasters
(fire) or by harvest of timber are erodible, highly so if timber harvest
is poorly managed.
Mineral pollutants are a problem of substantial importance to the
mining industry. Mineral pollution arises from contact of water with
mining refuse and with ore and rock formations exposed by the mining
activities. Acid drainage, though most popularly attributed to coal
mining, is a common problem in this industry. The acid mine drainage is
generated in large quantities; it can be a very serious problem to com-
munities located near the source, and is a substantial economic and en-
vironmental burden to urbanized areas in heavily mined regions. In
addition to acid and salinity or hardness minerals, mine drainage is a
carrier, usually in trace quantities, of a number of mineral elements
(lead, arsenic, zinc, cadmium, copper) which are a toxic threat at
sufficiently high concentrations.
Nutrient elements, chiefly nitrogen and phosphorus, are emitted
from agricultural lands as well as from the remainder of the rural areas
on which rainfall or irrigation is sufficient to support plant and animal
life. The rates of emission are greatest from lands managed for intensive
production of crops and livestock. It is estimated that perhaps 1 million
metric tons, of a total of 5 to 6 million metric tons of nitrogen lost to
surface and groundwaters, are attributable to the use of fertilizers.
vii
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Pesticides are widely used in agriculture, less extensively in
silviculture, construction, and mining. These may be transported to
water resources by careless application, by spray drift, by runoff and
by seepage or infiltration. The extent of the hazard depends greatly
on the properties of the pesticide and the care exercised in its use.
Organic wastes are transported to streams chiefly in runoff
water, and have essentially the same adverse effects as organic wastes
of domestic and industrial origin. Crop debris, livestock wastes, waste
petroleum products, forest litter, and numerous solid waste materials
are included in this type of waste material. Organic wastes of animal
and human origin are a source of biological pollutants, some of which
are disease producing.
Thermal pollution—the elevation of temperature in surface waters--
is of concern in silviculture, where removal of tree cover along stream
banks exposes the water to the sun's rays.
The magnitudes of the impacts of these pollutants, from the four
sources, vary in direct proportion to the quality of the management of
specific activities within agriculture, silviculture, construction and
mining. A terraced field is substantially less subject to erosion than
is a field tilled up and down the slope. Well designed haul roads in
silviculture and construction erode much less severely than unplanned
roads; and strip mined areas returned immediately to an effectively re-
claimed state cease to be significant sources of acid drainage, mineral
pollutants and sediments. The extent of pollution from specific agri-
cultural, silvicultural, construction and mining activities is therefore
greatly affected by the care exercised by the forester, the farmer, the
livestock operator, the mining industry, and the construction industry.
Planning for water quality management in watersheds and other
planning regions can be effective only if the relationships involving
inputs and outputs of various pollutants are understood, and if the effects
of the pollutants on water quality can be reliably assessed. Further, it
is essential that methods for predicting inputs and outputs be available
to the planner. These predictive methods are available in varying degrees
of usefulness and sophistication for sediment, thermal pollution and mine
drainage, and are generally unavailable in useful form for pesticides,
nutrients, heavy metals, biological pollutants, and organic wastes. A
substantial and very useful fund of information and data is on hand for
use in describing base-line characteristics of water quality planning
regions, and for developing the rules of thumb, equations, nomographs
and other predictive tools needed by the planner.
viii
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1.0 INTRODUCTION
The quality of this nation's water resources is a combined
function of natural processes, and processes which are attributed to
man's activities. Natural processes tend to be nondiscrete and diffuse,
and create discharges to the environment not amenable to treatment; such
processes and discharges are said to be nonpoint. Much of man's contri-
bution to water quality derives from discrete, localized operations which
generate point pollutional discharges amenable to isolation and treat-
ment. Man is also a substantial originator of nonpoint discharges to
the environment. Nonpoint sources of discharge for which man must ac-
cept responsibility include agriculture; mining; urban and rural con-
struction, urban storm runoff; nonurban based recreational activity,
i.e., camping, fishing and hunting; and silviculture. It is increas-
ingly apparent that these and other nonpoint sources are a substantial
deterrent to achievement of water quality goals. Accordingly, the
Congress has decreed in the 1972 amendments to the Water Quality Act
that specified nonpoint sources of pollution shall be characterized and
plans formulated for amelioration of pollution originating from them.
The study reported herein was undertaken to provide documen-
tation of presently available knowledge in four areas: silviculture,
agriculture, mining, and construction. The body of knowledge of concern
is the nature (kinds of pollutants, their sources, and their relative
importance) and extent (the magnitude of pollutant emissions: quanti-
ties, concentrations) of nonpoint water pollution. Particularly im-
portant are factors which relate an emitted pollutant to its source,
for the study is designed to assist the planner/engineer in evaluating
nonpoint sources of pollutants and their effects on water quality in
regional planning areas.
This report presents results of a 3-month study directed to
this need. Specific objectives of the program were:
1. To provide descriptions of nonpoint sources information
relevant to water pollution problems, including the nature of sources,
type of pollutants, relative importance of pollutants from each source,
and pollution loads related to natural and operational factors.
2. To determine methods, techniques, and procedures that can
be used for identifying, measuring, and evaluating the nature and extent
of the pollutants from nonpoint sources.
3. To provide analyses of the effect of nonpoint sources pol-
lutants on water quality management.
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Information derived from existing reports, papers, handbooks,
and from concerned researchers and private and governmental agencies
served as the basis for the study. Physical, chemical, and biological
aspects of water pollution were considered.
The following were investigated as sources of pollution:
1. Agriculture: croplands, grasslands, and livestock.
2. Silviculture: forest culture, harvesting, and logging
practices.
3. Mining: new, current, and abandoned surface and subsur-
face mines, and associated sites and facilities.
4. Construction: land development, highways and roads, and
other heavy construction.
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2.0 SUMMARY DISCUSSION
2.1 Introduction
Silviculture, agriculture, construction and mining have unique
and distinguishing characteristics, and each activity has a somewhat
unique set of nonpoint pollution problems. Similarities are perhaps
more striking than differences, from the environmental point of view.
In this section, the general features of nonpoint pollution from the
four sources in the aggregate are presented, followed by discussions
of methods for assessment of prediction of the extent of nonpoint pol-
lution and an enumeration of sources and types of information and data
available for use by the planner/engineer.
2.2 The Nature of Nonpoint Pollution from Agriculture, Silviculture,
Mining, and Construction
The total land area in the 50 states of this country is 916
million hectares (2.264 billion acres). Land use data vary from year
to year; on an average, one-half of this area is classified as "land
in farms," and the remainder as "land not in farms."i/ Urban America
occupies about 25 million hectares!!!/ (60 million acres), so almost 97%
of the land area is rural in nature. Essentially all of the rural land
is a source of nonpoint pollution, as is a substantial fraction of the
urban land area. The present study is concerned with four sources of
nonpoint pollution which are systematically influenced by commercial
activities of man. These sources therefore generate pollutants in re-
lation to the nature and extent of man's influence, and the pollution
is amenable to control through modification of commercial activities.
Two of the four sources of concern in this study—agriculture
and silviculture — together occupy 647» of the total land area in the
United States. Construction and mining together occupy only about 0.67o
of the total land area. The four nonpoint sources are, for purposes
of this study, subdivided into a total of nine use categories, as shown
in Table 2-1.
The area allocated to construction, 590,000 hectares (1 mil-
lion acres), is that area brought under development annually for housing,
highways, and like purposes.—' Commercial forest, 202 million hectares
(500 million acres), is forest land which is producing or is capable of
producing industrial wood, and has not been withdrawn from timber
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TABLE 2-1
LAND USE DATA
Millions of Reference
Hectares Acres or Note
Far land in Grass 218 540 16
Cropland, Plus Farmsteads and Roads.§/ 167 412 15
Construction (Annual) 0.59 1.5 16
Commercial Forest Including Farm
Woodlands and Forests 202 500 16
Annual Harvest of Forests (Growing
Stock) (4.45) (11) a,b/
Subsurface Mines 2.8 7 22
Surface Mines 1.2 3 22
Active Surface Mines (0.12-0.16) (0.3-0.4) c/
Mineral Waste Storage 1.2 3 22
592.79 1,466.5
a/ Calculated from data presented in Tables 779 and 781, Agricultural
Statistics, 1972, United States Department of Agriculture (Ref. 16).
b_/ Commercial forest acreage includes acreage harvested annually.
£/ Area involved annually in surface mining, estimated from analyses of
rates of growth in surface mining from 1920 to 1970 and predictions
of growth through year 2000.^.'
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utilization by statute or administrative regulation!^/ (about 105 million
hectares (260 million acres) of forest land is not available for pro-
duction of industrial wood) . Approximately 27o of the commercial timber
inventory is harvested each year, which translates into an annual
harvested area of 4-5 million hectares (10-12 million acres). The har-
vested forest acreage was calculated from data on timber inventories
and timber removals presented in Agricultural Statistics, 1972.jA/
The acreage involved in subsurface mines (2.8 million hectares
(7 million acres)) is only in part disturbed at the surface in a manner
directly attributed to the mining activity. Much of this surface area
is used for other purposes—parks, industry, cities, forests—particularly
if the mines have been abandoned. Surface mining has to date affected
1,200,000 hectares (3 million acres) of land,-^/ and an equal land area
is dedicated to storage of mineral wastes from mining activities. Sur-
face mining currently affects about 140,000 hectares (350,000 acres) of
land annually (see Table 2-1).
Cropland, grassland, and commercial forest are on the basis of
land area potentially large contributors of pollution. The remaining
sources in Table 2-1, construction and mining, involve relatively small
areas of land, and would appear on this basis to have less potential to
degrade water quality. Generation of pollution from land under these
various uses is governed chiefly by the manner of use, however. The
pollutant load yielded by a particular class of land is the product of
an appropriate pollution emission factor determined by land use practices,
and the area dedicated to the particular use.
It is informative to consider agriculture, silviculture, con-
struction and mining from the standpoint of total nationwide generation
to water pollution. The planner/engineer is nearly always concerned with
local or regional water quality, however, and thus requires local or
regional emission factors for watersheds which are affected by some com-
bination of construction, agriculture, silviculture, and mining.
Several classes of pollutants from agriculture, silviculture,
mining, and construction have been identified as significant degraders
of water quality. These are discussed, in summary fashion, below.
2.2.1 Sediment: Representative data for on-site erosion from
several types of sources are shown in Table 2-2.
If one assumes that grassland and forest represent the "natural"
state for cropland and construction land, the comparisons in Table 2-2
lead to the conclusion that tillage practices are responsible for 95-99%
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of the erosion from cropland; and that construction activities result in
99.57<> of the sediment eroded from construction sites.
An approximate relative ranking of the contributions of sedi-
ment (on-site), on a nationwide basis, from the seven types of nonpoint
sources is presented in Table 2-3.
TABLE 2-3
RELATIVE EROSION FROM VARIOUS LAND USES: NATIONWIDE
Commercial Forests 1
Abandoned Surface Mines < 1
Active Surface Mines 2
Construction 6
Harvested Forests 11
Grassland 11
Cropland 168
Cropland clearly is the major source of sediment. It has been
credited with responsibility for 507<> of the sediment delivered to streams
and lakes, which totals about 1.8 billion metric tons (2 billion tons)
annually (or half the on-site erosively generated sedimented production
rate of 3.6 billion metric tons (4 billion tons) per year. Erosion
from cropland varies widely in response to a number of variables: rain-
fall and rainfall intensity; type of crop; soil characteristics; topog-
raphy; type of tillage; and conservation practices such as terracing
and contour tillage. With good management, a particular operation can
reduce erosion substantially from the rate which occurs when croplands
are managed without concern for erosion.
The erosion attributed in Tables 2-2 and 2-3 to grassland is
that which results from adequately managed grassland. Overgrazing, and
the resultant loss of groundcover, can greatly increase the erodibility
of grassland.
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Construction and surface mining activities yield sediment at
quite high rates. Each of these activities is a less significant source
of sediment than cropland on a nationwide yield basis. However, both
rates are quite high from the standpoint of creation of local problems
such as plugging storm sewers and blanketing spawning areas with silt.
Both types of activities have high sediment delivery ratios (fraction
of on-site sediment delivered to water bodies) relative to cropland and
other land uses.
Well-stocked, well-managed forest land can be remarkably re-
sistant to erosion. Indeed, intense rainfall can be absorbed without
runoff by a forest with good tree cover and a forest floor well covered
with duff (decaying twigs, leaves, etc.). Forests devastated by wild-
fire and disease become highly susceptible to erosion. The harvest of
trees from a forest creates a temporary condition which promotes erosion.
Good silvicultural management practices can, as in agriculture, markedly
minimize the adverse effects of timber harvesting.
Sediment is rated as the most significant of the pollutants
from agriculture, silviculture and construction, and it also ranks high
as a pollutant from surface mining.
2.2.2 Mineral pollutants; In some parts of the country min-
erals arising from nonpoint pollution sources present more serious water
quality problems than does sediment. The affected areas are normally
associated with mining activities. While the sphere of influence of the
mineral pollution is more localized than that of sediment, it is a
serious water quality problem in the localized regions where it occurs.
This section discusses three types of mineral pollutants:
acid mine drainage, salinity, and heavy metals.
(a) Acid mine drainage: Acid mine drainage is a mixture
of sulfuric acid and iron and aluminum salts which arises from the oxida-
tion of pyritic materials associated with coal and mineral deposits. It
is found in parts of Appalachia and in the western United States. Not
all mining areas have mine drainage. Even in heavily mined areas of
Appalachia, mine drainage has not been noted at many mining operations.
An accurate current assessment of the mine drainage
problem is difficult, because: (1) abatement efforts are being imple-
mented; (2) new areas of active mines are being worked; and (3) mined
out areas are being shut down. In addition, the volume and composition
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of mine drainage depends greatly upon local physiographical conditions,
i.e., geology, hydrology, and topography. Thus, it is virtually impos-
sible to describe a "typical" acid mine drainage.
Mine drainage in the Appalachian Region of the United
States has been the most completely characterized. In 1969, the
Appalachian Regional Commission published a six-volume report detail-
ing all aspects of the mine drainage problem in the Appalachia.2/
This report has served as the basis for planning mine
drainage control and abatement projects in that region. At the time of
the Appalachian Regional Commission's report, about 2 million kg of
acidity (as calcium carbonate equivalent) was emitted daily in Appalachia.
Since that time, the amount of acidity emitted as mine drainage has been
reduced.
Mine drainage in Appalachia comes from three main sources:
underground mines, surface mines, and spoil (gob) piles. The mines in-
clude active and inactive mines. The gob piles are mining refuse, dis-
carded from coal processing operations, which contain pyritic materials.
The contour strip-mines in Appalachia have often left mine spoil on the
downslope of hills, and acidic discharges complicate the sediment problem
from strip-mining in the area.
In the western United States, mine drainage is associated
with hard rock minerals (copper, silver, gold, molybdenum, etc.), rather
than coal. The problem is somewhat different than in Appalachia, since
rainfall in the Rocky Mountain Region is quite variable. Indeed, in
some of the arid parts of the West, mine drainage does not occur, simply
because there is no water available for its formation.
Mine drainage in the West is less well characterized than
it is in Appalachia. The U.S. Geological Survey, Water Resources Divi-
sion, Colorado District, is presently conducting a study^A/ on the "Ef-
fects of Mining on Surface Water Quality Exclusive of Uranium Mining in
Colorado." This study will present data on the current status of mine
drainage (and heavy metal) pollution in Colorado, and should serve as a
basis for planning of mine drainage control and abatement efforts.
Acid mine drainage can be readily neutralized to form
neutral salts. Thus, calcium sulfate salinity (the neutralized end
product of sulfuric acid and limestone) in waters is commonly associated
with neutralized mine drainage.
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(b) Salinity: Saline water is common throughout many
parts of the country, particularly in western United States groundwaters.
Differentiation between salinity arising from man's activities and from
natural phenomena is difficult. All natural waters contain salts of
various types and in various concentrations. Some of the salinity is
attributable to runoff from agricultural and forest land, some to
neutralized mine drainage, and regions of intensive irrigation, to ir-
rigation return flows. Irrigation return flow has been excluded from
the scope of this study.
The salinity problem in the Colorado River Basin has
been the subject of an in-depth study. Results of this study have been
recently summarized,.£/ and extensive field data are available in open
file reports which can be reviewed in the offices of Region VIII, En-
vironmental Protection Agency, Denver, Colorado.
The Colorado River Basin Study recognizes two basic
causes of salinity in streams: salt loading and salt concentrating.
Salt loading is associated with discharge of mineral salts into
stream systems in municipal and industrial wastes, and in irrigation
return flows. Natural sources such as springs, influent groundwater,
and runoff are also major sources of salt loading. On the other hand,
salt concentrating is associated with consumptive use of water. No
mineral salts are added, but the concentration of salt increases as a
result of water lost from the stream system.
As mentioned above, neutralized acid mine drainage is a
source of saline pollution. Acid mine drainage can be neutralized by
treatment processes typified by addition of lime in a water treatment
plant or by natural processes (mine drainage passing through formations
containing limestone or calcareous shale). For those cases where the
acid mine drainage discharge is small and the stream receiving the
drainage is large, the acid is often neutralized by the natural bi-
carbonate alkalinity in the receiving stream.
A major problem associated with neutralized acid mine
drainage is the calcium and magnesium sulfate neutralization products.
The calcium (or magnesium) sulfate contributes greatly to the hardness
of the neutralized water. The hardness is of the "permanent" type,
and the water usually requires additional treatment with soda ash in
water to soften to acceptable levels.
Softening hard water with soda ash (or by ion exchange)
does not reduce salinity. The softening process merely replaces calcium
10
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or magnesium sulfate with sodium sulfate. In parts of Pennsylvania, the
principal sources of water supply is surface water contaminated with
mine drainage. The high concentrations of sodium sulfate in the lime-
neutralized, soda ash-softened water are a source of concern in these
communities.8.7
(c) Heavy metals: The third type of mineral pollution
considered—heavy metals--is less well characterized than are mine drain-
age and salinity. The most readily identifiable heavy metal pollutant
sources are associated with mining operations, particularly those in the
western United States. Heavy metals in pesticides used in agriculture
are potential pollutants. However, the heavy metal pollution potential
of pesticides is less well defined than that associated with mining-
related activities.
Acid mine drainage has the potential of leaching heavy
metals from rock strata through which it passes. Most mine drainage
contains iron, manganese, and aluminum, the aluminum arising from dis-
solution of clay materials. Manganese is present because it is a com-
mon impurity in pyrite. In the western United States, trace concentra-
tions of the following heavy metals are often found: arsenic, antimony,
cadmium, cobalt, copper, lead, mercury, nickel and zinc.
Arsenic arises in mine drainage through the oxidation
of arsenopyrite, and iron-arsenic sulfide associated with some hard
rock ores. Arsenopyrite undergoes the same types of reactions as does
ordinary pyrite, thus creating an acid mine drainage containing arsenic.
A part of the heavy metal pollution potential in the
western United States arises from sediment laid down in valleys from
uncontrolled mineral processing operations. In many mineral processing
operations in the West, mineral tailings were discarded into the near-
est streams. The tailings often contained heavy metals. Although tail-
ings impoundments (ponds) are now required, the sediment laid down in
stream beds prior to control is a potential heavy metal source. For
example, mercury has been found in groundwater associated with tailings
discharge from the Homestake Mine (gold) in South Dakota.
Some heavy metals in western waters arise from natural
sources. Arsenic not associated with mining!^./ has been found in some
Nevada water supplies in concentrations in excess of public health
standards.
11
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2.2.3 Nutrients: Nutrient elements, particularly nitrogen
and phosphorus, are major nonpoint pollutants. These elements are
abundant in nature, and it thus is difficult to deduce the specific
origin of most of the nutrient elements present in this country's water
supplies. Phosphorus is a pollutant of concern because of its role in
eutrophication, and nitrogen likewise is involved in eutrophication
processes. Ammonia, a reduced form of nitrogen, is toxic to aquatic
life at low concentration. Oxidized nitrogen, chiefly nitrate, is
present in most waters, and can be a direct threat to human health at
higher concentrations.
In addition to naturally available nitrogen and phosphorus,
the nutrient elements are derived from fertilizers and livestock wastes
in large quantities.
Commercial fertilizer is currently consumed in the United
States at a rate of about 37 million metric tons (41 million tons) per
year.AiL' Total plant nutrients (nitrogen, phosphorus, and potassium)
contained in the commercial fertilizer is about 15.5 million metric
tons (17 million tons). The quantity of nitrogen in commercial fertil-
izer, about 7.3 million metric tons (8 million tons) per year, is about
one-third of estimates^./ of annual inputs to the soil compartment. The
phosphorus content of commercial fertilizer (about 1.9 million metric
tons, 2.1 million tons annually) is approximately 1.5 times the phos-
phorus content of livestock wastes. Livestock wastes and commercial
fertilizer combined contain some 12 million metric tons of nitrogen
per year (13 million tons), and 3 million metric tons of phosporus
per year (3.3 million tons).
The quantities of nitrogen which escape to surface and ground-
waters has been estimated^/ to be 5.5 million metric tons (6 million
tons) per year. More than half is presumed to be transported on sedi-
ment and the remainder by leaching. It has further been estimated that
10-15% of the nitrogen entering the system via fertilizers is lost to
water.
Total phosphorus emissions±£/ from nonpoint sources have been
estimated to be 0.73 million metric tons (0.8 million tons) per year,
or about 25% of the phosphorus made available annually in the form of
fertilizer and livestock wastes. Phosphate emissions are closely re-
lated to erosion, since phosphate sorbs strongly on soil and resists
leaching. Nitrogen in both the reduced (ammonia) and oxidized (nitrate)
state is water soluble, and nitrogen emissions occur, both to surface
and groundwaters.
12
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Nutrient emissions from various sources should be weighted to
take into consideration the amounts of fertilizer and livestock waste
added to the land, size of the land area treated, and the relative re-
sistance of the land use to erosion. Approximately 757o of the commer-
cial fertilizer and essentially all of the livestock wastes are con-
centrated on cropland and pasture/range land. As with emissions of
sediment, cropland is a large single source of nutrient elements.
2.2.4 Pesticides: Pesticides are released directly into the
environment in the course of their intended use. Unfortunately, the
relationship between quantities of applied pesticide and the quantities
which become a water pollutant are not well defined. Water pollution
from pesticides is a function of the properties of a chemical, of its
mode and rate of use, and of the care exercised in application.
Most pesticide chemicals are toxic to man and higher animals.
They may also affect lower organisms, including organisms that are part
of the vital natural biological waste degradation and/or oxygen produc-
tion mechanisms. Persistent pesticides and/or pesticide metabolites
and degradation products may accumulate in the environment, and some
pesticides may biomagnify in ecosystems. The latter problem is of
special concern in water quality management.
(a) Pesticides in agriculture: Chemical pesticides in-
cluding insecticides, miticides, fungicides, herbicides, nematicides,
rodenticides, plant growth regulators, desiccants, and others are used
extensively in U.S. agriculture for the protection of crops and live-
stock from pests. The total quantity of pesticides used annually for
this purpose is not known exactly. The U.S. Department of Agriculture!!/
has estimated that farm uses of pesticides account for 55% of the total
domestic use of pesticides. On this basis the department estimated
pesticide use by farmers in 1966 and 1969 as follows:
Active Ingredients
Million kg (Ib)
1966 1969
Insecticides 88.5 (195) 90.8 (200)
Herbicides 56.8 (125) 99.5 (175)
Fungicides 15.0 (33) 16.0 (35)
Total 160.3 (353) 186.3 (410)
13
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The U.S. Department of Agriculturei2.' recently published
data on the estimated extent of chemical weed control in the United
States in 1959, 1962, 1965, and 1968. According to this report, the
herbicide-treated acreage increased from 21.5 million hectares (53 mil-
lion acres) in 1959 to 60.7 million hectares (150 million acres) in
1968. The largest increases in treated acres were on land grown to
corn, small grains, cotton, soybeans, and sorghum.
(b) Pesticides in silviculture: The U.S. Department of
Agriculture.!!/ reports that forest insects and diseases are responsible
for losses in the U.S. each year that far exceed the losses from forest
fires. Current annual forest mortality due to insects and diseases com-
bined is estimated at about 68 million m3 (2.4 billion cu ft). It is
estimated that insects and diseases cause an additional, equal volume, of
growth loss. Forest losses would be about 28 million m^ (1.0 billion
cu ft) higher if no pest control activities were carried out. The use
of chemical insecticides and fungicides is credited with about two-
thirds of this saving.
Major pest control operations in 1969 by federal, state
and private interests combined are summarized in a report by the USDA's
Forest Service.IP-' Over 1.25 million trees were treated for insect
pests such as the southern pine beetle and the white pine weevil, and
9,660 hectares (23,868 acres) were treated for the spruce budworm.
The U.S. Department of AgriculturelZ/ reports that in
1970, about 310,000 Ib of insecticides and fumigants were used by the
Forest Service for insect control. Pesticides used included ethylenedi-
bromide, 107,000 kg (235,000 Ib); fenitrothion, 23,000 kg (51,000 Ib);
carbaryl, 6,350 kg (14,000 Ib); and smaller quantities of malathion,
benzene hexachloride (BHC), and lindane. Two forest pests that ac-
counted for a major part of the use of these chemical insecticides were
the gypsy moth and spruce budworm.
The U.S. Forest Service has made a concerted effort in
recent years to move away from the use of persistent insectides, toward
increased reliance on cultural, biological and integrated control methods
and the use of nonpersistent, more specific chemicals.—' The service
has made no aerial applications of DDT since 1967. Its use of BHC de-
creased from 3,990 kg (8,790 Ib) in 1966, to 26 kg (57 Ib) in 1970. The
total use of pesticides in these programs has been reduced from about
614,300 kg (1,353,000 Ib) in 1965, to about 141,000 kg (310,000 Ib) in
1970.
14
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Herbicides are used in silviculture more frequently than
insecticides and fungicides, but still only a very small portion of
forest land is treated with herbicides in any given year.—' Herbicides
are used mostly to control undesirable plant species and weeds in new
plantings. Herbicides have also helped to prevent forest fires by re-
ducing growth of combustible plant materials on fire breaks and along
forest roads.
The U.S. Forest Service sprayed 108,702 hectares (268,666
acres) for the control of noxious weeds or undesirable woody vegetation
in 1969. This included about 33,600 hectares (83,000 acres) treated
with 2,4,5-T, alone or in a mixture with 2,4-D.l£/
The USDAli/ estimated that 187,000 hectares (463,000
acres) of forest plantings (presumably including publicly as well as
privately owned lands) were treated with chemical herbicides in 1968,
an increase from an estimated 111,000 hectares (274,000 acres) treated
in 1962. Twenty-two states contributed data to this report. Of these,
19 reported an upward trend in herbicide usage in forest plantings; one
state reported a stationary trend, two states a downward trend.
(c) Pesticides in construction: Pesticides may become
environmental pollutants as a result of construction activities basi-
cally in two different ways:
1. Pesticides may be used during the construction work
to protect the building, highway, etc., from attack by pests such as
insects, weeds, and diseases.
2. Construction work may involve movement of soil con-
taining pesticide residues from prior use of pesticides on the site.
Increased soil erosion usually associated with such earth movements may
mobilize such pesticide residues and increase their rate of passive
transport into waterways.
The most important use of chemical insecticides in con-
struction activities is the protection of wooden structures and struc-
tural elements from attack by subterranean termites. Persistent
chlorinated hydrocarbon insecticides including chlordane, aldrin,
dieldrin, and heptachlor are the insecticides primarily used for con-
trol of, or protection against; subterranean termites. These insecti-
cides provide 18 to 20 years protection in most instances. It is
generally agreed that there is very little likelihood of environmental
contamination from the proper use of persistent insecticides against
termites.
15
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Herbicides are sometimes used in construction projects
such as paving of parking lots, driveways, secondary or county roads,
or in similar situations where a relatively thin layer of concrete,
asphalt, blacktop, or other material is laid down. The herbicide(s)
are applied to the soil surface to prevent sturdy weeds from growing
through the pavement. Again, this type of pesticide use entails very
little risk of environmental contamination because the method of ap-
plication prevents pesticide transport away from the site of applica-
tion.
(d) Pesticides in mining: The only significant use of
pesticides in connection with active mining operations consist of
termite protection. Some herbicides may be used during land reclamation
operations.
2.2.5 Biodegradable pollutants: Agricultural and silvi-
cultural activities generate tremendous quantities of natural organic
waste materials which are potential nonpoint pollutants. Moreover,
all four sources—agriculture, silviculture, construction, and mining--
distribute synthetic or foreign organic substances in the environment
from which they have the potential to migrate into surface and ground-
water. The major sources of organic wastes are livestock wastes; crop
debris; forest litter, including annual leaf fall; and waste petroleum
products (lubricating oils and greases, waste crankcase oil, and pesti-
cide solvents or dispersants). Other less significant sources are
cleaning solvents, waste paints and degraded surface coatings, waste
materials from building and construction, and innumerable rural waste
items.
That this source of potential pollution is not insigifnicant
is shown by the fact that animal wastes amount to about 1.8 billion
metric tons (2 billion tons) per year,!!/ or nearly 2 metric tons/
hectare (1 ton per acre) if distributed uniformly throughout the United
States. This waste is restricted to approximately one-half the total
land area, and localized areas can be highly loaded with animal wastes.
Crop debris can be generated at rates of several metric tons per hectare.
The so-called "natural" organic wastes are, in well managed
agricultural and silviculture operations, returned to the land and re-
cycled by physical and biological degradation. The foreign or syn-
thetic organic substances usually are dispersed fairly uniformly on
land, where they in time are also degraded. Certain of these substances
may be difficult to degrade, and will accumulate in the rural environ-
ment. The PCB (polychlorinated biphenyl) class of refractory organic
16
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materials exemplifies the latter problem. In this case a substance not
a normal part of agricultural, etc., operations has become a very nearly
permanent part of the environment, and is transmitted within the environ-
ment by nonpoint transport schemes.
On an overall basis, however, the biodegradable material load
is accommodated fairly well on the land. A certain fraction, neverthe-
less, finds its way into the water resources. There it can be a physical
nuisance and a physical obstruction to aquatic processes, by blanketing
spawning beds or interfering with light and energy transmission. The
most serious effect is biochemical, for microbial degradation of pollu-
tant organic loads interferes with usual aquatic biological processes,
and may result in depletion of dissolved oxygen to a level inadequate
for aquatic animal life.
A majority of the organic waste material deposited in streams
is transported thereto by erosion and runoff. For this reason, organic
pollution is most severe where organic-laden surface covering is sub-
jected to extreme erosive conditions. Tree harvesting from forests ex-
poses forest litter to erosive forces, and the litter is an important
source of organic pollution. Similarly, landspreading of livestock
wastes will, if improperly carried out, yield a condition in which the
wastes are highly susceptible to transport to water bodies via surface
runoff.
2.2.6 Thermal pollution: Thermal pollution from solar radi-
ation is a nonpoint problem in silviculture. Destruction of shade
cover over forest-based streams can result in several degree rise in
temperature compared to a shaded stream.z./ The change in temperature
is often sufficient to cause considerable alterations of the aquatic
ecosystems. The nature and extent of thermal pollution are well docu-
mented, and methods for analysis at the planning level are available.
2.2.7 Radioactivity: Traces of radioactive nonpoint pollu-
tants are generated by-products of certain mining operations, and ad-
ditionally are a by-product of fossil-fuel production and combustion.
The radioactive mineral mining industry is, of course, a source of
nonpoint radiation, though this industry strives to handle both prod-
ucts and by-products as "point" materials. The environment is being
extensively monitored for radioactivity. Levels of radioactivity in
aquatic systems are routinely below levels judged to be hazardous.
2.2.8 Microbial pollution: Pollution of streams, reservoirs,
and groundwater by disease transmitting organisms is a problem which
17
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is not well characterized. The discharge of pathogens is associated most
closely with livestock production. The extent of pathogen-containing
discharges into surface waters is poorly documented. Pathogen contents
of groundwater are minimal from nonpoint sources, particularly if the
livestock operation is well managed. Nevertheless, microbial pollution
is a continuing area of concern.
2.3 Models for Predicting Nonpoint Pollution
Prediction methods for nonpoint pollution can vary from very
simple rules of thumb to very complicated computer procedures. The
planner or engineer concerned with nonpoint pollution needs to have
better tools than general rules of thumb, but less complicated than
sophisticated models which involve the use of electronic computers.
Existing prediction methods tend to be over-general, since they de-
scribe an average system in which pollutants are generated and trans-
ported. The real system is often significantly different from the
average, and in most cases can best be described as the summation of
several subsystems, each subsystem having been evaluated in terms re-
flecting its uniqueness.
Evaluation of the subsystems is usually based upon data of
many types obtained from several kinds of samplings. The data obtained
from a specific sample reflect conditions at a specific point in time
and space, i.e., the time when the sample was taken at the sampling
station. Thus, the planner/engineer needs to assess the data obtained
from a particular sample in relationship to a base line established by
many observations and analyses collected over a long time period.
This section describes criteria which are needed for better
prediction models; a method for presenting base-line information, and
an example in which prediction model criteria are applied to sediment
production at a construction site.
2.3.1 Criteria for prediction models: The planner/engineer
dealing with nonpoint pollution seeks three pieces of information:
1. What pollutants have been generated and dispersed;
2. How much pollutant has been generated; and
3. Do the data deviate significantly from the base line?
18
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What pollutants are generated and dispersed within a region is
usually determined by the types of activities which are occurring within
the region. The pollutant sources, both point and nonpoint, are usually
well-known and recognized. The nonpoint pollutants generated from agri-
culture, silviculture, mining, and construction are described in sub-
sequent sections of this report.
How much pollutant is generated can be addressed by several
procedures. For the case of sediment pollution, the Universal Soil Loss
Equation— and the Musgrave Equation—' for erosion losses have found
widespread utilization. Specifics of the two soil loss equations are
presented in Section 3.0. For the case of chemical pollutants, knowledge
of flows and pollutant concentrations is required to establish quantities
emitted.
The question of whether a set of analytical data deviate sig-
nificantly from base-line data is of crucial importance. Data obtained
from an individual sample reflect conditions at a particular point in
time and space. If the data are significantly different from similar
data taken at the same spatial point but at different times, then it can
be concluded that some event has occurred in the vicinity of the sampling
station which has affected the sample. Such a conclusion assumes, of
course, that the analyses have been properly performed and that the
sample is representative.
Sufficient data are available in many parts of the country to
establish base-line data for many pollutants. These data need to be
analyzed by statistical methods so that pollutant base-line data can be
expressed by rules of thumb, equations, and nomographs. Such statisti-
cal analyses have provided the basis for the soil loss equations,!!-!^/
equations for predicting thermal pollution,^.' and for preparation of
nomographs which describe several specific pollutional situations.
2.3.2 The Hydrograph; A method for presenting base-line
information: The base-line data including the nomographs, predictive
equations, and rules of thumb, provide a frame of reference with which
subsequent data obtained for various pollutants can be compared. Base-
line information can arise from many sources besides chemical analysis
performed to describe water quality. For example, the discharge of run-
off as a function of time is often summarized in a hydrograph. The
hydrograph can be used as the basis for developing base-line data for
surface runoff, the common method for transporting pollutants from land
into surface waters.
19
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A hypothetical hydrograph is presented in Figure 2-1. The
shape of the hydrograph will depend upon several factors: rainfall
amount, rainfall duration, rainfall intensity, and soil classification.
The amount of discharge is determined by the area and topography of the
drainage basin. In regions of similar topography, a large drainage
area will produce more runoff than a small drainage area. On the other
hand, a small compact drainage area with steep slopes would produce
more runoff than a larger, more elongated watershed having gentle
slopes.
The shape of the hydrograph will vary with respect to rainfall
duration and intensity in the following way. A storm of heavy rainfall
over a short duration will peak towards the left side of the hydrograph.
A gentle rain over a long duration will peak towards the right and tail
off more slowly. Effects of rainfall intensity and rainfall duration
on the hydrograph are shown in Figure 2-2. Similarly, a rainstorm in
an area of highly permeable soil will show a long time lag between the
time the storm begins and the time that runoff peaks. A similar event
in an area with tight clayey soil will be shifted to the left and peak
at a much earlier time.
The hydrograph consists of three basic segments:
1. The approach segment, AB, reflecting the time lag between
commencement of rainfall and the commencement of runoff;
2. The rising segment, BD, reflecting increased runoff until
it peaks at point D; and
3. The recession flow, DF, reflecting decreased runoff after
rainfall has ceased.
The inflection points in the rising and receding curves, C
and E, respectively, define the crest of peak segment of the hydrograph,
CDE. Point F represents the return to normal base flow.
The construction of hydrographs is a straightforward procedure,
although somewhat tedious. Information required and methods for con-
structing hydrographs have been presented by Ogrosky and Mockus.l^/
These authors also present methods for interpreting the hydrograph, and
interpolating standard hydrographs (called unit hydrographs) to specific
runoff events. A unit hydrograph describing a particular drainage basin
may be used for similar basins by introducing other values into the
parametric equations from which the unit hydrograph is constructed.
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Data inputs needed for constructing hydrographs include;
drainage basin area, duration of rainfall, amount of rainfall, excess
rainfall (above that absorbed by the soil), infiltration rates, and soil
types. Since the hydrograph construction is straightforward, computer
techniques for plotting the hydrograph are certainly applicable.
2.3.2 Application of a hydrographic data base to sediment
pollution: The hydrograph is designed for use with runoff discharge,
and does not specifically deal with pollutants that may be contained in
the runoff. Since material in runoff is the prime source of nonpoint
pollution, the planner/engineer needs to know how much and what kinds
of pollutants can be expected in the runoff.
The principles outlined above have been applied to the specific
problem of sediment in runoff at a highway construction site by Swerdon
and Kountz.JJL/ In this study, information from hydrographic analysis
provided the "volume" factor for determining sediment concentrations in
runoff. The "mass" factor in the concentration was supplied by the ap-
plication of the soil loss equation over a 24-hr storm period yielding
4.6 cm (1.8 in.) of rain. This storm was typical of one in the area
during the time of construction. By a straightforward manipulation of
predicted sediment yields during the standard storm, and of predicted
volume and flow distribution of runoff, it was possible to determine
accurately catch basin design parameters for retaining sediment during
the construction of an interstate highway segment in Pennsylvania.
The approach of Swerdon and Kountz yielded a sediment concen-
tration curve as a function of time. The shape of this curve was very
similar to that of the hydrograph shown in Figure 2-1. The only practi-
cal difference between the sediment concentration curve and the hydro-
graph was the difference in units along the Y-axis of the plot.
The sediment concentration levels were determined by applying
the soil loss equation to several subareas within the main drainage area
of concern. The soil losses for a 24-hr 4.6-cm rainfall were estimated
for each subarea. These losses were then totaled and divided by the
volume of runoff. The summation of data arising from the application
of the soil loss equation to a number of subareas in the drainage basin
is not a formidable problem. Methods for quickly summing over the sub-
areas have been presented by Swerdon and Kountz. These summation prin-
ciples are applicable to any source of nonpoint pollutants to obtain
usable pollutant production estimates.
The sediment concentration-time curves generated by Swerdon and
Kountz are illustrative of a potentially useful approach for the planner
23
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concerned with nonpoint pollution. For example, several plots of sediment
concentration as functions of storm duration will show results expected
from several storm intensities, indicate how much sediment can be ex-
pected during a variety of rainfall events, when the sediment loads would
peak, and how long a stream would exhibit sediment concentrations above
those found in base flow.
The resulting family of curves contain a useful description of
base-line conditions. They will provide a ready means to determine when
an unusual polluting condition exists. And they will provide the basis
for predicting response to control measures and to disturbances in the
watershed.
The planner in each region will necessarily have to consider
the parametric values and basic characteristics which describe his water-
shed (or other area of interest), develop this information into descrip-
tive models, and continue the process of evaluation through to develop-
ment of predictive tools which suit his needs. Much useful information
is available and accessible to the planner, and is very nearly adequate
for describing base-line characteristics. Details of procedures and
techniques for translating this information into useful descriptive and
predictive models are in some instances adequately developed (e.g., for
prediction of erosion specific aspects of mine drainage, and thermal ef-
fects on streams), and in other instances (e.g., pesticides, nutrients,
and heavy metals) inadequately developed.
2.4 Sources of Information Relevant to Assessment of Nonpoint Pollution
Information and data of considerable variety are needed to
evaluate nonpoint pollution problems and develop plans for their rectifi-
cation. Water quality data for the region of interest are a necessity.
Other needed information includes soil and geologic data, climatologi-
cal data, topographic information, statistics on land use and livestock
production, and statistics on the use of fertilizers and pesticides.
Sources of information are listed in Table 2-4.
The following federal agencies have aerial photographs for
many parts of the United States; Department of the Interior—Geological
Survey, Topographic Division; Department of Agriculture—Agricultural
Stabilization and Conservation Service, Soil Conservation Service, and
Forest Service; Department of Commerce—National Ocean Survey; Depart-
ment of the Air Force, National Aeronautics and Space Administration.
Also, various state agencies and commercial aerial survey and mapping
firms are sources of aerial maps and photographs.
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The following Federal and state agencies have basin and project
reports and special reports: Department of the Army—Corps of
Engineers; Department of the Interior—Bureau of Land Management,
Bureau of Reclamation, Bureau of Mines, Fish and Wildlife Service,
and National Park Service ; Environmental Protection Agency;
Department of Agriculture—Forest Service and Soil Conservation
Service; state departments of water resources, public-works power
authorities, and planning commissions.
30
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REFERENCES
1. Anderson, H. W., and J. R. Wallis, "Some Interpretation of Sediment
Sources and Causes, Pacific Coast Basin in Oregon and California,"
Proceedings Federal In.teragency Sedimentation Conference, 1963,
U.S. Department of Agriculture, Miscellaneous Publication No. 970,
pp. 22-30 (1965).
2. Appalachian Regional Commission, Acid Mine Drainage in Appalachia,
Washington, B.C. (1969).
3. Blackman, Jr., William C., et al., "Mineral Pollution in the Colorado
River Basin," J. Water Pollution Control Federation, 4Jj_(7) , pp.
1517-1557 (1973).
4. Brown, G. W., "Forestry and Water Quality," Oregon State University,
Corvallis, Oregon, 74 pages (1972).
5. Committee on Nitrate Accumulation, "Accumulation of Nitrate,"
National Academy of Sciences, Washington, D.C. (1972).
6. Cywin, A., and E. Y. Hendricks, "Proceedings of the National Con-
ference on Sediment Control," U.S. Department of Housing and Urban
Development, Washington, D.C., 14-16 September 1969.
7. Curtis, Willie R., "Strip Mining, Erosion, and Sedimentation," paper
presented at the 1970 Annual Meeting of American Society of Agri-
cultural Engineers, Minneapolis, Minnesota, 7-10 July 1970.
8. Demchalk, John, Private Communication, Commonwealth of Pennsylvania,
Department of Environmental Resources, Harrisburg, Pennsylvania.
9. Environmental Protection Agency, "Report on Pollution Affecting
Water Quality of the Cheyenne River System, Western South Dakota,"
Division of Field Investigations, Denver Center, Denver, Colorado;
EPA Region VII, Kansas City, Missouri; and EPA Region VIII, Denver,
Colorado, September 1971.
10. Ketcham, D., "Statement Before the Committee on Agriculture, House
of Representatives, 92nd Congress, First Session, on the Federal
Pesticide Control Act of 1971," pp. 152-164, U.S. Government Print-
ing Office, Washington, D.C. (1971).
31
-------
11. Musgrave, G. W., "The Quantitative Evaluation of Factors in Water
Erosion - A First Approximation," J. Soil and Water Conserv., pp.
133-138 (1947).
12. Ogrosky, H. 0., and Victor Mockus, "Hydrology in Agricultural Lands,"
in Handbook of Applied Hydrology, Chapter 21, Ven Te Chow, Ed.,
McGraw-Hill Book Company, New York (1964).
13. Rice, R. W., and J. R. Wallis, "How a Logging Operation Can Affect
Streamflow," Forest Industries, 89,, pp. 38-40 (1962).
14. Scott, Robert, Private Communication, Environmental Protection
Agency, Region IX, San Francisco, California.
15. Swerdon, Paul M., and R. Rupert Kountz, Sediment Runoff Control at
Highway Construction Sites; A Guide for Water Quality Protection,
Engineering Research Bulletin B-108, Pennsylvania State University,
College of Engineering, University Park, Pennsylvania, January
1973.
16. U.S. Department of Agriculture, "Agricultural Statistics - 1972."
17. U.S. Department of Agriculture, "Patterns of Pesticide Use and
Reduction in Use as Related to Social and Economic Factors,"
Pesticide Study Series - 10, Environmental Protection Agency,
U.S. Government Printing Office, Washington, D.C. (1972).
18. U.S. Department of Agriculture, "Two-Thirds of our Land: A
National Inventory," Soil Conservation Service, Program Aid No.
984, SCS-USDA (1971).
19. U.S. Department of Agriculture, "Extent and Cost of Weed Control
with Herbicides and an Evaluation of Important Weeds, 1968,"
Economic Research Service, Extension Service, and Agricultural
Research Service, ARS-H-1 (1972).
20. U.S. Department of Agriculture, "The Pesticide Review, 1971,"
Agricultural Stabilization and Conservation Service, Washington,
D.C. (1972).
21. U.S. Department of Interior, FWPCA, Robert S. Kerr Water Research
Center, Ada, Oklahoma, "Pollution Implications of Animal Wastes--
A Forward Oriented Review," Proc. Animal Waste Management Con-
ference, FWPCA, Missouri Basin Region, Kansas City, Missouri,
July 1968.
32
-------
22. U.S. Department of Interior, Surface Mining and Our Environment:
A Special Report to the Nation, U.S. Government Printing Office,
Washington, B.C. (1967).
23. Wadleigh, C. H., "Wastes in Relation to Agriculture and Forestry,"
USDA Misc. Pub. No. 1065. March 1968.
24. Wentz, Dennis, "Effects of Mining on Surface Water Quality Exclusive
of Uranium Mining in Colorado," U.S. Geological Survey, Water
Resources Division, Colorado District, Denver, Colorado, to be
published.
25. Wischmeier, W. H., and D. D. Smith, "Predicting Rainfall-Erosion
Losses from Cropland East of the Rocky Mountains," Agriculture
Handbook No. 282. ARS-USDA, May 1965.
33
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3.0 AGRICULTURE
3.1 Introduction
The impact of agriculture on the nation's water resources is
significant. Farmland in grass, pasture, and cropland plus farmsteads
and roads total over 385 million hectares (950 million acres) of land
area in the United States, and is scattered across the face of the land,
intimately connecting with nearly all of the major water sources. Crop-
land represents about 157 million hectares (387 million acres) of this
farmland (see Table 2-1).
The major uses of water include industrial use, irrigation,
public water supplies, navigation, recreation, and rural domestic uses.
The quantity of water used for irrigation ranks second only to that for
industrial use. Of the estimated 339 billion gallons of water consumed
QQ /
daily in the United States more than 357<> is used for irrigation. —' The
impact of the use of water for irrigation is limited mostly to the 17
western states where about 14 million hectares (35 million acres) of the
total 16 million hectares (39 million acres) of irrigated land are
situated.
The trend in agriculture is to employ modern technologies at
ever increasing levels of complexity involving the use of fertilizers,
pesticides, irrigation systems, and confined animal feedlots. A con-
sequence of this trend will be the increased potential for water pollution
both in the surface water and in the groundwater. Protecting water quality
will become a major concern for agriculture.
3.2 Sources of Pollution from Agriculture
The pollutants resulting from agricultural discharges include
sediments, salt loads, nutrients, pesticides, organic loads, and pathogens.
Sediment resulting from soil erosion is regarded as the largest pollutant
that affects water quality. Agricultural lands, particularly cropland,
are large contributers of sediment. HolemanPA' estimated the total erosion
rate per year for the contiguous United States to be over 3.6 billion
metric tons (4 billion tons), of which about 1.8 billion metric tons
(2 billion tons) washes into streams and 0.9 billion metric tons (1 billion
ton) reaches tide waters. The national conservation needs inventory of
the Soil Conservation Service estimated in 1971 that the total sediment
yield from cropland per year was more than 0.9 billion metric ton (1 bil-
lion ton). Thus, cropland is responsible for about 50% of the total
35
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sediment yield in inland waterways. Only a fourth of the total yield
travels to the ocean. Sediment also carries with it significant quanti-
ties of plant nutrients, pesticides, organic and inorganic matter, patho-
gens, and other water pollutants.
About 1.8 billion metric tons (2 billion tons) of livestock
wastes are produced annually in the United States.—- Of this quantity,
the liquid wastes are estimated to be over 360 million metric tons (400
million tons). As much as 50% of these wastes may be produced in feed-
lots. While most of these waste materials are confined and eventually
spread on farm acreage, the runoff and seepage from this source poses a
significant pollution hazard. Conservation treatment of the spreading
area eliminates or significantly reduces runoff and the pollution hazard.
Commercial fertilizers consumed during 1972 amount to about 37
million metric tons (41 million tons) in the United States. These fertil-
izers contain roughly 20% nitrogen, 5.2% phosphorus, and 8.8% potassium.
Farmers use about 75% of the fertilizer consumed in the United States.
The composition of plant nutrients in commercial fertilizers applied in
different states varies considerably. For example, in Nebraska, the com-
position of commercial fertilizers consumed during 1970 averaged about 40%
nitrogen, 5% phosphorus, and 3% potassium. For Iowa, these values were
approximately 27% nitrogen, 7% phosphorus, and 11% potassium.22.'
Some of these nutrients are transported, together with naturally
occurring nutrient elements, to surface and groundwaters.
Irrigated agriculture involves leaching and transport of dis-
solved minerals in soils, and flushing the unwanted salts from the soil.
About 607» of irrigation water is lost by evapotranspiration, while the re-
mainder is returned by surface runoff and subsurface flow to surface
waters and to groundwater storage. The return flows carry large quanti-
ties of minerals and degrade the water quality of the receiving streams.
Pesticides are designed to be lethal to target organisms, and
many are toxic to nontarget organisms. Four major categories are impor-
tant in agriculture: insecticides, fungicides, herbicides, and rodenti-
cides. According to Piraentel, of nearly 454 million kilograms: (1 billion
pounds) of pesticides applied in the United States during 1970, about 70%
was for farm use and the remaining 30% for public and governmental use.—
It is anticipated that the use of pesticides will increase tenfold within
the next 20 years.
The threat from pesticides is primarily due to their persis-
tence in the aquatic environment, where fish and other food chain or-
ganisms accumulate pesticides and their metabolites or degradation products.
36
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This phenomenon of biological magnification appears to be especially
significant with the fat-soluble pesticides.
Organic loads from agricultural activities include rural waste-
waters, animal wastes, crop residues, and food processing wastes. When
these substances are carried to a water body, they exert a high biochemical
oxygen demand (BOD).
Agriculture wastes are a source of pathogens. Diseases may be
transmitted through soil, water, or air when these wastes come in contact
with plants and animals. Agricultural losses caused by infectious agents
of livestock and poultry have been substantial. Wadleigh has summarized
the cases of diseases transmitted by infectious agents and allergens
affecting plants and animals from agricultural wastes. '
3.3 Pollutant Transport
There are three modes of transport of pollutants from agricul-
tural sources to water: (1) by runoff to surface water; (2) by infiltra-
tion and percolation to subsurface water; and (3) by wind to surface waters.
The pollutant may be dissolved and carried by water, or may be
adsorbed and transported with sediment. When transported in an aqueous
phase, hydrological factors describing the motion of the water from the
source to the point of discharge in a stream or a lake must be known to
predict the extent of pollution. In the sediment phase, the rates of
transport of suspended sediment, as well as the bedload, must be considered.
In a watershed, interactions of several sources which contribute to a
common sink are complex and difficult to predict.
The mechanisms of nutrient transport and deposition in water-
ways have been investigated under several local conditions and are basi-
cally known. However, a knowledge of these mechanisms is not adequate
to determine the extent of nutrient losses from individual sources such
as fertilizers and livestock wastes, or how these losses may be affected
by soil and land characteristics, and management systems.
3.3.1 Water: Runoff from croplands, animal feedlots, and
pasture and rangelands is a major mode of transport of pollutants that
enter a water resource. Subsurface drainage may also carry significant
quantities of pollutants that are dissolved in water. Surface water
carries suspended sediment in large quantities. Many pollutants such
as phosphates and pesticides are tightly bound to sediments and are thereby
transported to river and reservoir bottom muds. Though phosphorus is held
strongly by bottom sediments, the net release of even a small fraction to
the surface water can adversely affect water quality.
37
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Groundwater pollution stems mainly from increased nitrate con-
centrations from percolation and infiltration. Leachates from feedlots
have been shown to contribute to nitrates in the groundwater. Ground-
water salinity has been increased through crop irrigation and return to
the water table. Increased irrigation in the Pacific coastal area by
withdrawing groundwater has created pressure differences in the saltwater-
freshwater interface, resulting in saltwater intrusion.
3.3.2 Wind: The process of wind erosion consists of particle
detachment, transport, and deposition. The critical or threshold condi-
tions under which soil movement is initiated have been the subject of
intensive wind-tunnel and other laboratory experiments. Chepil— and
Chepil and Milne— found that the most significant factor influencing
the threshold velocity of any soil is the size of the soil grains. This
critical velocity is a minimum for particles between 0.1 and 0.15 mm in
diameter.
The movement of soil by wind action takes place through the
following mechanisms: (1) saltation; (2) surface creep; and (3) atmo-
spheric suspension. Saltation denotes the bouncing movement of particles
within a layer close to the ground surface. Surface creep is induced by
the impact of particles descending from saltation. Atmospheric suspen-
sion is the process by which fine soil particles are lifted into the tur-
bulent air stream and may be carried large distances.
The proportion of soil moved by wind varies widely for differ-
ent soils. Coarsely granulated soils erode by saltation and surface .
creep; finely pulverized soils, by saltation and atmospheric suspension.—
Ninety percent of the soil moved by wind is through saltation or surface
creep processes. The balance is through atmospheric suspension, which is
a source of water pollution by wind action.
The three major factors controlling wind erosion are the char-
acteristics of the wind, the soil, and the soil surface. The erodibility
of soil by wind is primarily determined by soil moisture, soil texture,
structure, and stability. According to Chepil. 6lA?/ a simple but effec-
tive index of soil erodibility is the proportion of soil fractions greater
than about 1 mm in diameter, as determined by dry sieving. Soil particles
with diameters less than about 1 mm are generally considered erodible,
while soils resistant to wind erosion contain at least two-thirds by
weight of fractions greater than 1 mm.
38
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The use of soil erodibi.li.ty index for wind erosion appears to
be limited. The extent of soil losses due to wind erosion has not been
systematically analyzed. Data indicating the quantity of wind-borne
sediment deposited in a water body are not currently available.
3.4 Extent of Pollution from Agriculture
The significance of pollution from agricultural sources in the
protection of our water resources is the subject of several conferences,
symposia, and reports in recent times.1,9-11,23,26-29,33,42,53,55,70,84,
93,107,115/ in addition, several papers describe the general and spe-
cific aspects of agricultural waste contributions to environmental
pollution.3,4,14,15,18,20,22.24,25.30,31.39,43.44,61-64.66.69.72.76.88-90.
92,96,101-105.108-112/ A detailed discussion is not attempted in this re-
port as the subject has been well documented in the published literature.
A brief overview will be presented in the following sections.
3.4.1 Cropland: Croplands rank as the largest producer of
sediment. Sediment is considered by far the most important water pollu-
tant from agriculture. About 1.8 billion metric tons (2 billion tons)
of sediment are washed into streams in the U.S. each year.—'
Wadleigh estimated the average analysis of sediment to be
0.1% nitrogen, 0.087, phosphorus (P), and 1.25% potassium (K). Thus, the
loss of nitrogen and phosphorus to our waterways would be approximately
1 kg of N per metric ton of sediment (2 Ib of N per ton), and 0.8 kg of P
per metric ton of sediment (1.6 Ib of P per ton). Erosion is thus an
important factor in loss of nutrients to surface waters. Many substances
which are either present on land as plant residues, are introduced on
cropland by man, or are produced as wastes by agricultural activities,
have significant effects when introduced into receiving waters. Of these,
the most publicized materials include pesticides and plant nutrients.
Pesticides have been receiving much attention due to their adverse eco-
logical effects on food chain organisms, especially on aquatic communi-
ties. The ban of persistent chemicals such as DDT highlights the degree
of concern in this area. However, the movement of pesticide residues from
cropland into waterways is a complex process, and depends on many factors
such as the physical and chemical properties of the toxicant, the formula-
tion, the rate and type of application, the crop to which it was applied,
tillage practices, topography of the field, topography of the area between
the application site and waterways, distance between application site and
waterways, weather conditions, and amount and velocity of rainfall follow-
ing application. Limited data are available to demonstrate quantitatively
how these factors will affect the relationships between quantities of
39
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pesticide input and pesticide residues in rivers, lakes and oceans.
Edwards—has summarized typical amounts of DDT in aquatic and in
terrestrial food webs (see Figure 3-1).
Most pesticide residues are found in the uppermost layer of
tilled cropland soils, i.e., in the stratum that becomes a "soil loss"
in the process of sheet erosion. Consequently, pesticide soil residue
data may be correlated with the sediment load of the waterways to de-
termine the extent of pesticide losses to surface waters.
Less dramatic, but equally alarming is the problem of lake
eutrophication, attributed in part to the application of fertilizers
on farmland. Of special concern are the major nutrients, phosphorus
and nitrogen. Nitrogen can find its way into groundwater or surface
water generally as a dissolved salt. The evidence suggests that nitro-
gen may be taken up at the root zone, escape to receiving ground or
surface waters, or evolve to the atmosphere through denitrification
processes. The nitrogen percolating into groundwater accumulates in
aquifers and contributes to potential problems of nitrate toxicity.
Estimates of the loss of nitrogen from agriculture sources
vary considerably. For example, in Upper Klamath Lake, Oregon, 20% of
the nitrogen was estimated to be derived from agricultural runoff. In
the Potomac River estuary, 31% was attributed to agricultural runoff,
while 54% of the nitrogen reaching Wisconsin surface waters has been
estimated to be derived from "rural" sources.£§/ Williford, e£ al.l-JA/
showed that while relatively large quantities of nitrogen were removed
in the leachates from a cropland, less than 0.23%, of the nitrogen re-
moved came from fertilizer-nitrogen. However, the sources contributing
nitrate to groundwater are not well established. Whether the nitrogen
comes from that which is naturally present in soil or is derived from
commercial fertilizers, the probability of nitrate escape with leaching
water increases with intensified agricultural operations.—'
Available data are not adequate to permit accurate estimates
of nitrogen losses from fertilizers to ground or surface waters.—' In
a dynamic soil-plant system, the behavior of nitrogen is complex. Several
processes occur simultaneously in nitrogen transport: fertilizer nitrogen
is taken up by plants; organic matter in the soil is mineralized; atmos-
pheric nitrogen is fixed either at the root zone symbiotically, or in
atmosphere; nitrogen is leached below the root zone into the soil; and
nitrification-denitrification processes are carried out by microorganisms.
However, the Committee on Nitrate Accumulation, National Academy
of Sciences,—' recently estimated that 10%-15% of fertilizer nitrogen
40
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41
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is lost to waterways, a total from this source, nationwide, of about
1 million metric tons. The total emitted from all sources to the
waterways was estimated to be 5.5 million metric tons. Of this total,
2.7 million were transported by erosion, 1.8 million by leaching of
native soil nitrogen, and 1.0 million by transport of fertilizers by
a combination of processes. A majority (about 90%) of the 5.5 million
metric tons discharged to the waterways is believed to be returned to
the atmosphere by denitrification.
It is evident from the above considerations, that a minority of
the nitrogen discharged to the water is derived from fertilizer nitrogen.
However, it follows that rates of discharge of nitrogen may reasonably
be expected to be enhanced by agricultural (and other) activities which
yield high local concentrations of nitrogen in soils and plant and animal
matter. Heavily fertilized croplands are thus expected to be higher-than-
average contributors of nitrogen to surface and groundwater. s. This con-
clusion is confirmed by numerous research studies—* * which indi-
cate general trends but do not permit precise quantification of yields
expected from specific types of agricultural land use. Recovery of fertili-
zer nitrogen by crops is often no higher than 30%.^P-/ The remainder is
returned to groundwater by leaching, carried off in surface runoff, re-
tained by soil, or released to the atmosphere by denitrification.
The data presented in the above paragraphs indicate that the
processes involved in the cycling of nitrogen in an agricultural ecosystem
are complex, and that losses of nitrogen to waterways vary substantially
from one agricultural system to another. Knowledge of nitrogen inputs by
symbiotic and nonsymbiotic fixation in rainfall, and by mineralization of
soil is fragmentary, as is knowledge of losses to waterways, to vegetative
or animal products, and to the atmosphere by volatilization and denitrifica-
tion.
95;
An American Waterworks Association task group-1— reports that
agricultural runoff is the greatest single contributor of nitrogen and
phosphorus to water.
The effect of irrigation return flows on water quality is signif-
icant. However, this important aspect of water quality was not within the
scope of the current study.
3.4.2 Livestock: Animal wastes are a major potential source of
water quality degradation. Runoff from barnyard and pastureland may con-
taminate water supplies, destroy fish and aquatic life in streams, and gen-
erally degrade water quality. Nitrate in groundwater in the vicinity of
42
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feedlots has been shown to be significantly higher in concentration than
at remote locations.^—^' It was also found that groundwater under feed-
lots frequently contained ammonia and organic carbon. Where feedlots are
located in humid regions, runoff and percolation combine to enhance the
possible loss of nitrogen to waterways.—'
According to the USDA, 1.8 billion metric tons (2 billion tons)
of livestock wastes were produced in the United States during 1972.— /
The potential pollution load in terms of population equivalents is esti-
mated to be 1.9 billion.—-' In other words, the volume of animal waste
produced in the U.S. is about 10 times that produced by the human popula-
tion. About one-half of this waste is produced by animals in confined
feeding.^./
The population equivalent values are an index of potential pollu-
tion; actual pollution is substantially less, by an unknown factor. While
a majority of livestock wastes is retained on the land, discharges to ground
and surface waters are a significant factor in water quality. The extent
is strongly influenced by the quality of management at the local level.
3.4.3 Farmland in grass or pasture: About 218 million hectares
(540 million acres) of land in the U.S. is used as grassland or pasture.
Keller and Smith—' found that soil below feedlots contained 2,240 kg of
nitrate nitrogen/hectare (2,000 Ib/acre), while the nitrate nitrogen in
the surface soil on adjoining areas ranged from 56 to 168 kg/hectare (50 to
150 Ib/acre). They noted that contamination from nitrates remained even
after an area was abandoned from animal use. Barnyards, feedlots, and
manure piles have been indicated as sources of excessive nitrate nitrogen
in shallow wells in Nebraska and Illinois.
Stewart£2/ found that nitrate concentrations in soil under feed-
lots ranged from almost none to more than 5,604 kg/hectare (5,000 Ib/acre)
in a 6.1 m (20 ft) profile with an average of 1,600 kg/hectare (1,436 lb/
acre) for 47 feedlots. Stewart, et al.— found that even though the ratio
of irrigated lands to feedlots was 200:1, calculations based on the average
nitrate content of the irrigated fields (excluding alfalfa) and the rate of
water moving through these profiles suggested that 28 to 34 kg of nitrogen/
hectare (25 to 30 Ib/acre) were lost annually from irrigated fields to the
water table. This indicated that although much larger amounts of nitrate/
unit area were usually present under feedlots, irrigated lands contributed
more total nitrate to the groundwater.
52/
Hutchinson and Viets— found that atmospheric ammonia measured
near feedlots was as much as 20 to 30 times greater than near control sites.
The conclusion was that surface waters in the immediate vicinity of a feed-
lot can become enriched in nitrogen by absorption of atmospheric ammonia
volatilized from the feedlot. These data seem to indicate that not only
are runoff and percolation sources of nitrogen from feedlots, but atmospheric
43
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nitrogen is a serious consideration as well. The potential water pollu-
tion problems from grassland and pastureland may be attributed to three
factors: sediment, livestock wastes, and chemicals. Pastures and pri-
vately owned grassland contribute to erosion and sediment problems, but
the contribution is small with good management practices compared to that
from other agricultural and open lands.—' Erosion from pasture and grass-
land is of the order of 50 to 100 metric tons/km2/year (150 to 300 tons/mile2/
year), or about 10% of the erosion from cropland.
Some of the earliest erosion problems in the West developed on
badly managed grasslands. The most publicized were those that occurred
after heavy sheep grazing in the mountains of the Wasatch Front in Utah,
where thunderstorms carried, on an average, the top 7.2 cm (2.9 in.) of
soil out of the mountain watershed onto the fertile valley below. A nearby
well-managed and undamaged watershed produced less than 0.002% of the sedi-
ment eroded from the mismanaged watershed. Improper management can thus
lead to very extensive erosion.
The conservation needs are dictated by land use practice. Pasture-
land needs are based on the condition of the plant cover in relation to the
potential of the soil to produce such vegetation, as well as for soil con-
servation.—
The pollution potential from wastes of livestock on pasture may
be significant if the topography of the land favors a high rate of runoff
into a nearby stream, and if grazing patterns are such that wastes accumu-
late chiefly in small areas close to surface waters. Limited data are
available on the actual impact of livestock wastes on stream water quality
in grassland or pasture. However, it appears that the water pollution po-
tential from animal wastes in grazing pastures and grasslands should be
minimal under good range management practices.
Studies of chemical treatment of rangeland for brush and weed
control using 2,4-D, dicamba, and 2,4,5-T indicate that these chemicals
rapidly degrade in the environment when used at recommended rates.—
The greatest amount of herbicide residue in water appears following run-
off shortly after application; residues decrease thereafter with each rain.
Picloram does not appear to sorb on soil extensively, nor is it detoxified
by microbes. Picloram is also more soluble than other herbicides such as
2,4-D and is one of several herbicides (Fenae, 2,3,6-TBA, and picloram)
of similar characteristics which have been observed in subsoils and are a
threat to water quality via leaching into subsurface drainage and dissolu-
tion in runoff waters. Their use should be restricted in areas where such
mechanisms of distribution are favored. Other herbicides such as 2,4-D,
are relatively insoluble, sorb on soil, and degrade readily, and the
44
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principal threat to water quality arises from possible transport in storm
runoff soon after application.
Unlike nitrogen, phosphorus is low in solubility, does not leach
readily into the ground, and has a strong affinity for soils, especially
clays. The majority of phosphorus that finds its way into the surface
water is transported through erosion processes. Hasler—' found, in an
undisturbed mud-water system, that the percentage as well as the amount
of phosphorus that is released to the superimposed water is very small.
o o
When P was placed at various depths in the mud, diffusion into the over-
lying noncirculating water was negligible from depths greater than 1 cm.
Thus, most lakes in the U.S. are considered to be phosphorus limited. Any
addition of phosphorus through organic wastes or land drainage will trigger
algal growth. The loss through drainage of phosphorus of fertilizer origin
can be significant. Smith estimated that up to 107o of the phosphorus may
be lost through drainage during the year of its application to potato fields
using commercial fertilizers.—
3.5 Prediction of the Nature and Extent of Nonpoint Pollution from
Agriculture
3.5.1 Introduction: There exists considerable literature on
the effects of specific pollutants of agricultural origin on water re-
sources. However, very few of these studies directly relate sources to
water quality. From a water resources management point of view, predic-
tion methods must relate the nature and extent of nonpoint pollution to
the various sources contributing this pollution to water quality. Since
a given watershed may contain a large number of agricultural sources, pre-
dicting the contribution of pollution from each of these sources is diffi-
cult unless a full input-output inventory of pollutants at the boundaries
of each source are known, together with the reaction rates during trans-
port and deposition in the water body. At present much potentially useful
data are available, but their actual usefulness is limited by uncertain-
ties imposed by physical descriptions of the system.
The methods summarized in this chapter are presented to help the
engineer/planner develop strategies for determining the stream pollution
from agricultural activities consistent with his resources. Since the
presented methods have different levels of complexity, the degree of con-
fidence one can assign to each method varies and is uncertain. However,
the methods presented have been tested under actual field conditions and
their general validity, in the specific use for which each was designed,
has been established. A basic limitation of these methods is the lack of
45
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correlation between the nature or the extent of water pollution and the
source from which the pollutant originated. Thus, the degree of success
that the engineer/planner will have is dictated by his ingenuity and
judgment in applying the presently available knowledge to his specific
problems.
3.5.2 Prediction methods:
(a) Summary of available methods for sediment prediction:
Sediment is characterized as the largest single water polluter. By ero-
sive action, sediment not only depletes valuable land resource, but it
also degrades water quality and helps to transport other pollutants. Con-
sequently, a major effort has been spent on the evaluation of methods to
predict the levels of sediment pollution contributed from different agri-
cultural sources.
Sediment prediction methods may be summarized under these
three categories: (1) erosion; (2) transport; and (3) yield. Table 3-1
shows a partial list of the available methods and some of these are sub-
sequently discussed in detail.
The empirical methods have been developed for all three
categories in great detail. However, statistical and simulation methods
have been developed primarily for transport and deposition processes.
Water erosion may be broadly classified into two groups:
1. Impact of raindrops on soil, sheet erosion, or further
removal of the soil particles by overland flow that can also cut small
channels, rill erosion. In either case the field surface is completely
smoothed by normal farm tillage methods.
2. A more severe and serious form of soil removal and trans-
port takes place during channel erosion, which is defined as the removal of
soil by concentration of flowing water to cause the formation of "channels."
The channel erosion removes so much soil that the resulting ditch cannot
be eliminated by normal field tillage methods. Gully erosion is closely
related to channel erosion and is usually without water except during a
rainstorm.
The erosion process of primary concern in predictive method-
O I /
ology is sheet erosion. Ellison— has shown experimentally that the quan-
tities of soil carried by raindrop splash during a 30-min period can be
expressed as
E = K (V/30.5)4'33 d1'07 (I/2.54)0'65 (3-1)
46
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TABLE 3-1
SUMMARY OF SEDIMENT PREDICTION METHODS
Process
Prediction Method Erosion Transport Deposition
1. Empirical
Ellison^. X
o 7 /
Musgrave— X - -
118/
Universal Soil Loss Equation X - -
41/
Einstein Bedload Function— - X -
Colby Modified Einstein^!/ ,, , - X -
Toffaleti Total Load Method— - X X
07 /
Lacey's Silt Theory—' - X X
Pemberton Modified Einstein— X
Reservoir Surveys: - - X
ARS
SCS
Corps of Engineers
Bureau of Reclamation
U.S. Geological Survey
2. Statistical
347
Flaxman— - - X
Sediment Rating-Flow Duration: - - X
U.S. Geological Survey
Bureau of Reclamation
Corps of Engineers
Woolhiser's Deterministic
Watershed Modelii^-/ XXX
3. Simulation
38/
ARS Upland Erosion Model— X
ARS USDAHL-73 Watershed Model— XXX
ARS "ACTMO" Chemical Transport
ModelTJiV _ x -
Negev's Watershed Model—' XXX
Stanford IV Model!!/ XXX
127
Hydrocomp Simulation— XXX
Huff Hydrologic Transport Model— X
Royal Institute (Sweden)
Hydrologic Model— XXX
Snyder's Parametric Hydrologic
Model M/ - X X
47
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where E is the soil intercepted in splash samplers (in g), V is the
velocity of drops (in cm/sec), d is the diameter of the drop in mm),
I is the intensity of rainfall (in cm/hr), and K is a constant. K
depends on the numbers and types of samplers and on type of soil.
Ellison plotted infiltration-capacity curves for four soil types, as
shown in Figure 3-2.
Musgravo ' *"*' in 1947 reported the results of analyses
of soil loss measurements for some 40,000 storms occurring on small plots
in the United States. Their results indicate that the soil loss by sheet
erosion varies according to the following relationship:
E, in m3 = 12 IR(S) 1-35L°'35(P3()) 1' 75
(3-2)
E, in acre in. = IR(S) 1'35(L)0-35(P3()) 1> 75,
where E is the soil loss per year, I is an erodibility factor, mea-
sured in centimeters (inches), R is a dimensionless cover factor, S is
the degree of slope in percent, L is the length of slope in meters (feet),
and ?3o is the maximum 30-min amount of rainfall, 2-year frequency in
centimeters (inches), R is expressed as a ratio of the erosion rate of the
field under the existing cover to the erosion rate for a continuous fallow
or row crop condition. Equation (3-2) is applicable to long-term average
soil losses for broad areas. The Musgrave Equation was shown to be a use-
ful tool for estimating the rate of sheet erosion on agricultural lands in
the more humid parts of the country.—'
A graphical solution of the Musgrave Equation was presented
by Lloyd and Eley-^2/ and is presented in Figure 3-3. The graph was de-
veloped primarily for soils located in northeastern United States. Soil
factor "I", R factor, and cropping factor "C" were presented under vary-
ing conditions. The nomograph presented is useful for an area where 3.2 cm
of rainfall in a 30-min period may be expected once in 2 years. For other
areas such as soils of the Northwest, similar documents have been prepared
by Lloyd and Eley.
Wischmeier and Smith=^-' developed in 1966 a prediction
equation called "Universal Soil Loss Equation" which takes into account
the influence of the total rainfall energy for a specific area rather than
the rainfall amount. The limitations of the Musgrave Equation (3-2) were
reduced by the development of the Universal Equation so that the new pre-
diction model would:
1. Improve and extend the soil erodibility and cropping
factors;
48
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|'|1 AVERAGE CURVES FOR ALL-TIME PERIODS
¥^4-SHOWING RELATIONS Of SOIL V IN RAINDROP-
I
SPLASH TO INFILTRATION SOILS I, SI, JIT, AND IZ
CRAMS Of SOIL £ IN RAINDROP-SPLASH
Figure 3-2 - Curves Showing the Relationship of Splash of Soil (E)
to Infiltration Capacity for Four Soil Types—'
49
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o\° §
fit (J
s
LENGTH OF SLOPE IN FEET
(METERS X3.28)
100
•2-
-3-
•4-
•5-
•6-
•7-
•8
•9-
in
60C
1-
2-
•3-
4-
•5-
6-
•7-
8-
• 9-
•10-
•II-
12-
500
1 -
2~
3-
-4-
h5-
-6-
-7-
•8-
9-
•IO-
•II-
•12-1
400
1 -
-2-
-3-
-4-
•5-
-6-
-7-
•8-
•9-
-10-
•II-
300
1 -
-2-
-3-
-4-
•5-
•6-
-7-
•8-
9
400
-3-
•6-
9-
12-
•15-
•18-
•21-
24-
27-
-30
•33-
300
-3-
-6-
-9-
-12-
-15-
18-
•21
24-
27-
30
200
-3-
-6-
•9-
-12-
15-
18-
•21
•24.
3OO
5-
-10-
15-
2O-
25-
•30-
35-
4O-
45-
•5O
PERCENT OF SLOPE
ROTATION FACTOR
1.0.80.60 .40 .30
.20 .18 .16
.12
.09
.10
Figure 3-3 - Nomograph for Probable Soil Loss Using
Musgrave Equation—'
50
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2. Overcome the deficiency of a single rainfall-intensity
factor that is not closely related to the number of erosive rainstorms per
year;
3. Predict erosion rates by storm season or crop year, in
addition to annual averages; and
4. Account for the effects of a multiplicity of cropping
sequences, crop yields, and crop residues.
The Universal Soil Loss Equation is
A=RKLSCP , (3-3)
where A is computed average annual soil loss per unit area; R is rain-
fall factor, or the number of erosion index units in a normal year's rain
(the erosion index is a measure of the erosive force of specified rainfall);
K is the soil credibility factor; L is the slope length factor; S is
the slope gradient factor; C is the cropping management factor; and P is
the erosion control practice factor.
The storm soil loss from cultivated fields is shown to be
directly proportional to the product of total kinetic energy E of the
storm and its maximum 30-min intensity I. The sum of the computed storm
El values for a given time period is a numerical measure of the erodibil-
ity of all the rainfall within that period. Thus, the R factor is ex-
pressed as
EEI
R 100 '
3
where E is the storm energy in units such as kg-m/m (foot-tons/acre-
inches), I is the maximum 30-min intensity. Analyses of U.S. Weather
Bureau rainfall statistics are used to develop El values, which are pre-
118/
sented by Wischmeier and Smith.-=-=2-' The El factors have not been eval-
uated from actual rainfall data for the western regions, and interim El
and R data have been developed by ARS for use in only non-orographic rain-
fall areas where rainstorms of high energy and intensity are common.-L2J
The soil credibility factor K defines the inherent erodibility of the
soil. Standard K values were developed for most soil types by the Soil
Conservation Service. Several factors influence the erodibility of cohe-
sive soils including texture, soil structure, thickness and permeability,
organic matter content, and nature of clay minerals. Typical K values of
23 major soils on which erosion plot studies were conducted have been re-
ported.H^.' K factors have been published recently by the SCS for soils
in the Southern Region.I22/
51
-------
The colloidal fraction of soil is the site of most of the
chemical and physical reactions taking place in the soil. Variations
in soil characteristics greatly influence the soil loss, and the binding
capacity of the soil for different pollutants. For example, clay par-
ticles have better affinity to colloidal and dissolved minerals than sand
or loam. Among clays, montmorillonite clays have higher ion exchange
capacities than kaolinite clays. The exchange capacity of kaolinite clay
was reported to be 3-15 meq/100 g, while that for montmorillonite clay was
80-100.— The erosion rates are not only influenced by the individual
soil size fractions in a given surface, but also by the relative stability
of the soil after detachment. There appears to be a sorting process in
which sands and silts settle out and the clay colloids remain in suspen-
sion. The electrochemical, chemical, and physical properties of the clays
have to be included in the models describing the erodibility of the soil.
Wischmeier and co-workers-—- in 1971, presented a soil
erodibility nomograph for computing the K factor if five soil parameters
are known, viz., percent silt, percent sand, organic matter content, struc-
ture and permeability. The nomograph is presented in Figure 3-4.
The soil loss is affected by both length and degree of slope.
For convenience in the field application, these two factors are combined
into a single topographic factor, LS. The soil loss ratio from any given
slope conditions can be readily determined by means of a set of graphs de-
veloped by the U.S. Agricultural Research Service and shown in Figure 3-5.
For slopes and slope lengths greater than those in Figure 3-5, data are
78 /
extrapolated^-2/ and presented in Figure 3-6. Data in Figure 3-6 may be
adjusted for field conditions based on experience and judgment.
8/
According to Chow,— the C factor is a complex factor to
evaluate because of the many different cropping and management combina-
tions in a given area. This is further complicated by the variable dis-
tribution of rainfall-erosion potential during different periods of crop
cover. Fertilizing, mulching, crop residues, crop sequence, and other
factors also influence the rate of soil loss. However, field workers in
SCS believe that evaluation of C factors is relatively uncomplicated.
According to them, the C factors have been worked out for a number of
cropping systems by the Soil Conservation Service so that it is relatively
easy to make these determinations in the field. The values of C factors
vary from 0 to 1^ and have been subjectively determined by SCS field
personnel. Since usually only a few management combinations are followed
in a given area, it would not be a problem unless the watersheds are ex-
tremely large.-2^.'
52
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a.
60
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o
o
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CD
CD
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CO
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ft
o
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CO
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-------
The P factor for croplands depends on the cropping practice
such as contour tillage, stripcropping on the contour, and stabilized
waterways. It also varies with the slope of land.
The Universal Soil Loss Equation was developed primarily
for predicting the soil loss on cultivated lands so that adequate soil
and water conservation practices can be initiated. The equation has not
been used in the past in watershed studies because factors reflecting the
effect of cover on pasture, range, and forest land had not been developed.
Q-l /
Recently Wischmeier—' developed cover factors for these land uses to
enable a broader application of the Universal Equation to watersheds.
Williams and Berndt have recently applied the Universal
Equation to watersheds by modifying all factors except the rainfall factor.
They developed an equation to compute sediment delivery ratios by using
multiple regression analysis of watershed characteristics:
D = 0.627 S0-403 ,
where D is the sediment delivery ratio, and S is the slope of main
channel in percent.
Erosion from beef cattle feedlots has been predicted by
Jeschke and Day—' by adapting the Universal Equation. The method is
being verified with field studies under Illinois conditions.
Recently, the Musgrave Equation (3-2) was reviewed by
3 to reflect t
irnham and co-
Musgrave Equation, which is:
several workers to reflect the factors in the Universal Equation (3-3).
32/
For example, Farnham and co-workers—' developed in 1966 a modified
1.35 , T x 1.35
(3-5)
where E is the average soil loss in centimeters per year, KR is the
product of soil erodibility factor and the rainfall factor from the
Universal Equation (3-3); P is the cover factor; S is slope in per-
cent (with 10% as a base). A comparison of Equations (3-3) and (3-5) by
Beer and co-workers—' showed that the Modified Musgrave Equation gave
better estimations of sheet and rill erosion than the Universal Equation
on 24 drainage basins. However, only limited use has been made of
Equation (3-5).
Another modification of the Musgrave Equation which has
been extensively used by the Soil Conservation Service substitutes the
56
-------
"K" and "C" factors from the Universal Soil Loss Equation for the "P" and
""
F" factors of the Musgrave Equation. . Thus,
.§!/
(3-6)
where E is the sheet erosion, metric tons per year; K is the soil credi-
bility factor; C is the cover factor; R is the rainfall factor; S is
the land slope in percent; and L is the length of slope in meters.
(b) Sediment transport in streams: Sediment transport in
streams has been studied by many investigators. Modern theories of sedi-
ment transport are based on studies in the 1930-1955 era by Schokditsch,
Meyer, Peter and co-workers; Colby; Einstein; Chien; Toffaleti; Lacey;
and Pemberton, among others.
A detailed discussion of the theoretical and practical de-
t hi
99/
velopments of sediment transport has been published by Graf,—' and by
USDA-Soil Conservation Service.
The theory and mathematical statement of sediment transport
is too complex for discussion in this report. Practical methods for deal-
ing with sediment transport are embodied in methods for measurement and pre-
diction of sediment yields.
(c) Sediment yield: The term "Sediment Yield" may be de-
fined as the amount of the eroded soil material that is transported and
deposited in a stream either as suspended sediment or as settled bed mate-
rial, or both.
Sediment yield is dependent on gross erosion in the water-
shed and on the ability of runoff to transport and deposit eroded material
into streams and reservoirs. The yield of a given area varies with chang-
ing patterns of precipitation, cover, and land use.
There are several ways to calculate the sediment yield of
a watershed, depending on the data available. Average annual sediment
yields may be obtained from: (1) gross erosion and sediment delivery
ratios; (2) measured sediment accumulations; (3) sediment-rating curves,
flow-duration techniques; and (4) predictive equations.
Gross erosion in a drainage area includes sheet and rill
erosion, and channel-type erosion (gullies, valley trenches, streambank
erosion, etc.). The sediment delivery ratio is that fraction of the soil
removed by gross erosion which is delivered to a stream.
57
-------
Y = E(D) (3-7)
where Y is the sediment yield, E is the gross erosion, and D is
the sediment delivery ratio.
Several factors affect sediment delivery ratios: type of
sediment sources, size and texture of erodible materials, climate, trans-
port systems, land use, proximity of sediment sources, source size, water-
shed characteristics, and the nature of depositional areas.
There are no generalized sediment delivery relationships that
can be applied to every watershed situation. However, several studies have
shown general trends in sediment delivery for specific areas. z2/ For
example, an analysis of data from widely scattered areas shows that the
sediment delivery ratios throughout the country roughly vary inversely as
the 0.2 power of the drainage area. This relationship is illustrated by
Figure 3-7. Rough estimates of sediment delivery ratios can be made
through the use of Figure 3-7, but such estimates should be blended with
judgment of other influencing factors such as soil texture, type of erosion,
and areas of deposition within the drainage area. Reservoir sediment depo-
sition surveys yield valuable data for establishing sediment yields. In
these surveys, the sediment inflow represents the inflow between survey
periods, which may not represent a long-time average inflow, depending on
the hydrologic period between surveys. It must be understood that reser-
voir deposition and sediment yield are not synonymous. The amount of
accumulated sediment is only a fraction of the sediment yield and must be
divided by the reservoir's trap efficiency to determine the yield. The
sediment yield of an unmeasured watershed may be estimated from that of
a measured watershed in the same or similar area by adjusting the ratio
of the drainage area raised to the 0.8 power :-i=-'
'8
where S£ is the sediment yield of unmeasured watershed; S is tne
sediment yield of measured watershed, i.e., measured annual sediment
deposition -f trap efficiency of surveyed reservoir; Ae is the drainage
area of unmeasured watershed; and A^ is the drainage area of measured
watershed.
The relationship shown in Equation (3-8) must be confined
generally to the humid areas east of the Rocky Mountains.—'
58
-------
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Several regression equations have been obtained for differ-
ent regions based on field data to relate delivery ratio with drainage
area and other factors: For the Southeast Piedmont region:—'
log D = 3.95 - 0.23 log 10 A
+ 0.51 log - - 2.79 log B . (3-9)
L
For western Iowa and northeast Missouri, based on a study of 24 reservoir
watersheds :2_t'
log D = 1.140 - 0.258 log A (Iowa data - Mule Creek), (3-10)
log D = 0.868 - 0.239 log A (Missouri data). (3-11)
81/
For the Red Hills area of south Kansas, western Oklahoma, and western Texas: —
log D = 2.943 - 0.824 log - , (3-12)
where D is the sediment delivery ratio, percent; R/L is the dimensionless
relief basin length ratio; A is the drainage area in hectares; and B is
the weighted mean bifurcation ratio (number of streams of any given order ^
number in the next higher order) .
A comparison of several graphical relationships indicated
the drainage area to be a better indicator of sediment delivery ratio. —
Thus, the equation:
log D = 1.534 - 0.142 log A (3-13)
appears to represent a large number of drainage areas studied.
35 /
Recently Flaxman — has developed a regression equation to
predict sediment yield in terms of four measurable independent factors for
11 western states of the U.S. The regression equation is:
log(4.75Y + 100) = 6.21 - 2.19 log(X1 + 100) + 0.06 log (X2 + 100)
- 0.02 log(X3 + 100) + 0.04 log(X4 + 100) , (3-14)
q
where Y is the sediment yield in m /hectare/year; X^ is the climate
factor (average precipitation, cm -f [0.71 (average annual temperature, °C) +
12.8] ; X2 is the topography factor [weighted average watershed slope, per-
cent = E (area of contour interval x percent slope) -f total area]; X3 is
60
-------
the coarseness of soil particles [percent of soil particles coarser than
1 mm in the surface top 5 cm (2 in.) of the soil profile] ; and XA is
the soil aggregation index [percent clay-size particles 2u or finer in
top 5 cm (2 in.) of the soil profile] . A nomograph is used to solve for
Y in Equation (3-14), and is presented in Figure 3-8.!£/
Equation (3-14) was found to best fit the observed data
when the computed yields are less than 1.4 m /hectare/year (0.3 acre-ft/
railed/year).
The predicted yields from Equation (3-14) exclude the
effect of gully and stream channel erosion, which must be added for com-
puting the gross yield.
Another method of predicting sediment yield is based on
sediment-discharge rating curve and flow duration methods, employed by
the Bureau of Reclamation.—' This method requires concurrent measure-
ment of streamflow and sediment amount. This method of obtaining data
is difficult and expensive on small streams. However, considerable
savings can be realized if samples are obtained during flood flow, in-
stead of daily sampling. Some samples are needed at lower flows in
addition to the flood flows. Data for developing flow-duration curves
are usually obtained from a stream gaging station, near the sampling
site. As examples, a sediment-discharge rating curve and a flow-duration
curve for the San Juan River are presented in Figures 3-9 and 3-10, re-
spectively. These figures were developed from 19 years of sediment sam-
pling data from the San Juan River at Bluff, Utah. The streamflow records
Q1 Q7/
in this case encompass the same time period as the sediment records. » '
Such parallel records are often not available, and extension of the sedi-
ment rating curve becomes an exercise of engineering judgment.
Thus, Strand?-!' calculated the yield rate in the San Juan
River Valley for the spring season to be 2.91 m^/hectare/year (0.612
acre-ft/mile/year), and 4.03 m-^/hectare/year (0.847 acre-ft/mile /year)
for other seasons. In these calculations, two assumptions were made:
(1) correction for unmeasured sediment was assumed to be 10% and 2070; and
(2) the sediment density was assumed to be the same as the density of
water. The reason for two correction factors on unmeasured sediments is
due to the sizes of sediment and volume of water during the spring runoff
which are different than those during the rest of the season. Direct
measurement of density by using core samples would yield more accurate
prediction. Correction for bedload may be made from Table 3-2.—l—
61
-------
X] Precipitation-Temperature Rate
\2 Weighted Average Slope in %
Soil Particle Size >1 .Omm in %
Aggregation Index
Y Sediment Predictive Yield, ac ft/miVyr
SEDIMENT PREDICTIVE YIELD EQUATION
log(Y + 100) = 6.21301 - 2.19113 log(X] +100)
+ 0.06034 log(X2 + 100)-0.01674 log(X3 + 100)
+ 0.04250 log(X4 + 100)
by E.M. Flaxman
Nomograph Solution by K.M. Smith
Figure 3-8 - Nomograph Solution of Equation 3-14—'
36/
62
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Figure 3-10 - Seasonal Flow-Duration Curves
at Bluff, Uta' '
for San Juan River
64
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Sediment yield rating curves can be constructed from
reservoir survey data » ' from watersheds having similar climatic,
topographic, and geologic properties. Figure 3-11 is such a curve de-
veloped for the arid Southwest.—' The relationship, sediment yield is
/-JO
proportional to (drainage area)u , appears to be valid for several
basins with similar characteristics.
*\ i I
Flaxman—used suspended sediment load measurements for
evaluating the sediment yield. Figure 3-12 shows the relationship be-
tween discharge and suspended sediment concentration (sediment-discharge
rating curve) for San Ramon Creek, California.
Among the most complex of discharge and suspended sedi-
ment concentration relationships existing in the West are those occurr-
ing in the eastern Washington and Oregon area. Figure 3-13 shows a plot
of data from the Walla Walla River in southeastern Washington. The seg-
ment (2) on the curve in Figure 3-13 reflects a rate of increase in sedi-
ment concentration many times the rate of increase of discharge. This
unusually large rate is attributable to an acceleration of soil erosion
with the thawing of the soil frost. Soil losses as much as 670 metric
tons/hectare/year (300 tons/acre/year) have been measured as rain or snow-
melt rills the slopes that are bare or are in poor cover.
Segment (1) in the curve (Figure 3-13) is interpreted as
the result of return flow from irrigation. The relatively high concen-
tration of sediment during the very low flows is diluted as discharge
increases.
Segment (3) in Figure 3-13 is indicative of sediment yields
under conditions of abnormally high discharge rates. That is, sediment
becomes available at rates disproportionate to the rate of increase in
discharge. This indicates the error that may occur if a straight line
relationship is extended too far. On the other hand, added stresses
exerted on a watershed by a storm of rare occurrence (20-50 year storm)
may expose new sources of sediment, and result in abnormally high sedi-
ment yields. To use these procedures, an array of data on sediment con-
centrations must be available to accompany discharge data, the latter
preferably at a wide range of flows. Sufficient knowledge of the water-
shed should be available to relate sources of sediment to the character-
istics of the plotted curves of data.
By relating watershed characteristics to suspended sedi-
ment concentration-discharge relationships, knowledge can be built up
to aid in obtaining the answers to the following questions:
66
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1. What are the dominant sources of sediment yield?
2. What is the approximate effect of these sources on
sediment concentrations?
3. What is the increase in sediment yield under disturbed
watershed conditions relative to yields under undisturbed watershed
conditions?
4. What are the effects of land treatment on the reduction
of erosion and sediment yield?
Because of the unusual conditions existing in the arid
Southwest, a new rating method was suggested by the Pacific Southwest
Interagency CommitteeZi' in 1968 to predict sediment yields, and to
supplement actual sediment yield measurements. These recommendations
apply to watersheds of more than 30 km (10 mile^) in size.
The sediment yields are divided into five classes with
corresponding ratings shown in Table 3-3.
TABLE 3-3
CLASSIFICATION OF SEDIMENT YIELD FOR PACIFIC SOUTHWEST-7-/
Class
1
2
3
4
5
Average Annual
Sediment Yield
o
m /hectare
r\
( acr e- feet /mile )
>15 (>3.0)
5-15 (1.0-3.0)
2.5- (0.5-1.0)
1 -2.5 (0.2-0.5)
<1 (<0.2)
Rat ing
>100
75-100
50- 75
25- 50
0- 25
70
-------
Nine factors were recommended for consideration in de-
termining the sediment yield classification. These are geology, soils,
climate, runoff, topography, ground cover, land use, upland erosion, and
channel erosion and sediment transport. The characteristics of each of
the nine factors which give that factor high, moderate, or low potential
for sediment yield are shown in Table 3-4. The sediment yield character-
istic of each factor is assigned a numerical value representing its rela-
tive significance (weight) in the yield rating, which is the sum of values
for each of the nine factors. Each of the nine factors shown in Table 3-4
are paired influences with the exception of topography. That is, geology
and soils are directly related as are climate and runoff, ground cover
and land use, and upland and channel erosion. Ground cover and land use
have a negative influence under better than average conditions. Their
impacts on sediment yield are therefore indicated as a negative influence
when providing better protection than the average.
In most cases, high values for the A through G factors
should correspond to high values for the H (upland erosion) and/or I
(channel erosion) factors.
Although only the high, moderate, and low sediment yield
levels are shown in Table 3-3, interpolation between these values may be
made.
Thus, a total rating of 92 would indicate that the sediment
yield is in Class 2, i.e., 5-15 m3/hectare/year (1-3 acre-ft/mile2/year).
This compares with a sediment yield of 9.3 m3/hectare/year (1.96 acre-ft/
mile^/year) as the average of a number of measurements in this area.
(d) Areas of application: The Bureau of Reclamation, in
the design of water supply projects, utilizes the sediment rating curve-
flow duration method for predicting the sediment yield in reservoirs.
Other methods used by the Bureau include sediment yield rating curves
from reservoir survey information, the suspended sediment method, and
erosion prediction equations such as the Modified Universal Soil Loss
Equation.
In the design of open channels, the Bureau estimates total
bed material discharge using the modified Einstein bedload function de-
veloped by Colby,—' or the transport of bedload based on the mean measured
stream velocity as reported by Colby.— Recently, PembertonZZ/ published
the Bureau's procedures, using adjustments to the Einstein bedload func-
tion, for predicting transport rates of total bedload of sand-size or
coarser material, by size fractions. Pemberton concluded that corrections
were needed in the Einstein bedload function for measured velocity and
71
-------
TABLE 3-4
SEDIMENT YIELD LEVELS AND THEIR RATINGS
FOR A WATERSHED OF 39 km2 (15 mile2) IN WESTERN COLORADO^/
Factors Sediment Yield Level Rating Potential
A Surface geology Marine shales
B Soils
C Climate
D Runoff
E Topography
F Ground cover
G Land use
H Upland erosion
erosion
10
Easily dispersed, high shrink-
swell characteristics 10
Infrequent convective storms,
freeze-thaw occurrence 7
High peakflows, low volumes 5
Moderate slopes 10
Sparse, little or no litter 10
Intensively grazed 10
More than 507» rill and gulley
25
I Channel erosion Occasionally eroding banks
and bed, but short flow
duration 5
10
10
10
10
20
10
10
25
25
Total
92
130
72
-------
for another parameter, namely the unmeasured portion of the sediment load,
by using the bedload or total load formulae. If sufficient data are not
available, the Bureau recommends adjustments to the suspended sediment
qi /
loads using the data shown in Table 3-2. —'
Because of the varying age of sediment in a reservoir, its
density will vary from time to time. An accurate estimation of density
is important in predicting the sediment yields in mass units. The most
accurate and direct method would be to weigh representative core samples.
However, this is not always possible. Figure 3-14 shows the variation of
dry unit weight of sediment with depth using both core sampler and gamma
probe.—' The Bureau of Reclamation procedure for density correction is
presented in Table 3-5,—' which was prepared using foot-pound units. An
equivalent table using the metric system is shown in Table 3-6. It must
be emphasized that in estimating the suspended sediment load, variation
of load with season is highly significant, as shown in Figure 3-15,2°.'
and that "average" values do not accurately reflect occasional high load-
ing rates.
Holeman^2' summarized procedures used in the SCS to estimate
sediment yields. These procedures include gross erosion and sediment de-
livery ratios, predictive equations for specific areas, suspended sediment
load by sediment-discharge rating curves, and reservoir sediment deposi-
tion surveys. These methods have already been discussed.
The Corps of Engineers' methods for predicting sediment
59/
yields were summarized recently by Livesey,—' who emphasized the need
for long-term reservoir survey data, especially for small watersheds.
(e) Simulation models: Several mathematical models have
been proposed to simulate the environmental conditions of a stream and to
predict the changes from upstream conditions. The hydrological model due
to Negev,—' Stanford IV Watershed Model,—' Hydrocomp Model,—'' Royal
Institute, Sweden Hydrologic Model,2/ Huff's Hydrologic Transport Model,—'
USDA Hydrologic Laboratory Model, USDAHL-73,5^./ Snyder's Parametric Hydro-
logic Model,M/ Woolhiser's Deterministic Model,112/ ARS "ACTMO"--Agricul-
tural Chemical Transport Model, 1—J and the Foster-Meyer Upland Erosion
Model,^/ are but a few examples of simulation techniques which employ
modern high speed digital and analog-digital computers. Recently,
discussed the need for water quality models in agriculture. He emphasized
the systems approach for study of hydrologic systems of watersheds, as
monitoring water quality by itself cannot always adequately pinpoint the
source of pollution.
73
-------
Dry Unit Weight in kg/m3
0
4 -
100
600
c 20 -
a.
0)
Q_
0>
Q
*— ft
- 10
- 12
24
28 32 36 40
Dry Unit Weight in lb/ftc
Figure 3-14 - Depth-Density Relation of Reservoir Sediment—'
58/
74
-------
TABLE 3-1
UNIT WEIGHT OF SEDIMENT IN SEDIMENT VOLUME COMPUTATIONS
TYPE OF
RESERVOIR OPERATION
INITIAL WEIGHTS
(Lara and Pemberton)
Wi
Clay
Silt
Sand
K FACTORS
(Lane and Koelzer)
K
Clay Silt Sand
I. Sediment always 26 70 97
submerged or nearly
submerged
II. Normally moderate 35 71 97
to considerable
reservoir
drawdown
16.0 5.7 0
8.4 1.8 0
III. Reservoir normally
empty
IV. River bed
Unit Weights
sediments
40
60
after various Units
Wave time (T)
WIG
w20
W30
W40
W50
= W
W
= w
_ W
- w
1
1
1
1
1
72
73
of
97 000
97 0 00
Time
= Wl + .4343K[^Y (logeT
+ .675K
+ .938K
+1.093K
+1.210K
+1.298K
W60 =
W70 =
W80 =
W
W90 =
W100=
W
W
W
1
1
1
Wl
W
i
1
+
+
+
+
+
1
1
1
1
1
>-i]
.372K
.438K
.493K
.542K
.588K
Sample Computations
Size Analysis:
Clay = 23%
Silt = 40%
Sand - 37%
100 Year Sediment Storage
Compute K
Reservoir Operation: Type II
Compute Wi
Wl = 35 (0.23) + 71 (0.40) + 97 (0.37)
Wl = 8.05 + 28.4 + 35.89 = 72.3 Ib/cu ft
W
K = 8.4 (0.23) + 1.8 (0.40) +0 100 = wl + 1.588 K
K = 1.932 + .72 = 2.652
100 = 72.3 + 1.58& (2.652)
100 = 72.3 + 4.2 = 76.5 Ib/cu ft
75
-------
TABLE 3
-fill/
UNIT WEIGHT OF SEDIMENT IN SEDIMENT VOLUME COMPUTATIONS
TYPE OF
RESERVOIR OPERATION
INITIAL WEIGHTS
(Lara and^ Pemberton)
Clay
Silt
Sand
K FACTORS
(Lane and Koelzer)
K
Clay Silt Sand
I. Sediment always 417 1,121 1,554
submerged or nearly
submerged
253.2 91.5 0
II. Normally moderate 562 1,138 1,554 134.5 28.9 0
to considerable
reservoir
drawdown
III. Reservoir normally
IV.
Unit
W
ave
empty
River bed
Weights
time
WIG =
w20 .
W30 =
w40 =
(T)
wl
wl
wl
Wi
wl
sediments
after various
642
963
Units
W f T
= 1 + .4343KJ —
"T" •
+
+1.
+1.
+1.
675K
938K
093K
210K
298K
W60 =
W70 =
W80 =
W90 =
W100=
1
1
,152
,170
1,554
1,554
000
000
of Time
(loge
W
W
w
w
w
I
1 +
1 +
1 +
1 +
1 +
T)
1.
1.
1.
1.
1.
-J
372K
43 8K
49 3K
542K
588K
Sample Computations
Size Analysis:
Clay = 23%
Silt = 40%
Sand - 37%
100 Year Sediment Storage
Compute K
Reservoir Operation: Type II
Compute ^1
W^ = 562 (0.23) + 1,138 (0.40) + 1,555 (0.37
WL = 129 + 455 + 575 = 1,159 kg/m3
K = 34.5 (0.23) + 28.9 (0.40) + 0 r,100
K = 31.0 + 11.55 = 42.55
W
" Wl + 1'588 K
+ i'588 («.55)
100 =
W10Q = 1,159 + 67.7 = 1,227 kg/nT
76
-------
70 r-
I 60
9
-------
3.5.3 Site survey and verification techniques: In order to
make reasonable estimates of the nature and extent of pollution from
agricultural sources, the engineer/planner may pursue two methods of
inquiry.
(a) Materials balance method: This method involves prepara-
tion of input-output tables on specific pollutant sources such as nutrients
and pesticides, and their rates of reaction in the aquatic environment.
Thus, the nutrient budget for a given watershed can be written as:
output = input - storage . (3-15)
Each term in the above expression may involve several sources. For agri-
cultural runoff from a farmland in a given watershed, the following ex-
pression can be evaluated :Zi'
Runoff = f [(fertilizers + animal manure + precipitation
4- advection + minerals dissolved + biological
transformations) - (storage + harvest removal
of crops + atmospheric transfer)]
(3-16)
Many of these terms are difficult to measure or estimate as different
rates and different forms of nutrients in the runoff affect the data.
(b) Measurement and analysis method; With statistically
valid samples obtained in a systematic water quality monitoring program,
one can establish relationships between any two or three factors such as
BOD vs. number of cattle, drainage area vs. sediment load, phosphorus vs.
sediment flow, and pesticide vs. runoff, for any watershed and for each
land use. When a man-made disturbance is suspected to be a cause of water
pollution, sampling and analysis of stream water and sediment can identify
the nature and extent of the disturbance and help to pinpoint the location
of the source.
The monitoring program must be carefully designed to insure
that necessary information of good quality is obtained without undue
expense. The boundaries of the drainage area must be defined before the
study. Sampling sites must be chosen based on land use and geographic
features such that the best estimate of the average reflects the majority
of the features. Both surface and subsurface water drainage should be
sampled and analyzed for pollutants. The analytical procedures can be
established rapidly with some experience so that nonsignificant pollutants
are not routinely analyzed.
78
-------
The location of sampling sites, and their distance from the
source will affect the accuracy of the stream monitoring data. Other fac-
tors which must be considered include antecedent rainfall, basin geometry,
nature of intervening discharges, and chemical and physical reaction rates.
Base line data will help establish the degree of man-induced
disturbance at a point upstream of the sampling site. Stream flow records
are kept on most streams by the U.S. Geological Survey, based on routine
monitoring of these streams. EPA and USGS maintain computerized stream
water quality data on most streams. USDA, through its Agricultural Research
Service and Soil Conservation Service also maintains stream surveillance
records. The Corps of Engineers and the Bureau of Reclamation likewise
maintain extensive sampling and analysis data on streams, lakes, and reser-
voirs. In the absence of such data on a small watershed for which water
quality is evaluated, on-site sampling will provide the required information.
While water quality monitoring is essential in evaluation
of pollution from nonpoint sources, stream monitoring methods have inherent
limitations. The selection of sampling sites may be limited by available
resources, which in turn will reflect the quality of data collected. The
monitoring of water quality in a watershed containing a large number of
pollution sources of similar nature may confuse the origin of pollutants
unless the runoff from each source is monitored. The distance from a source
to the point of discharge into a stream will influence the quantity of
pollutant entering the stream. Variations of distances from similar sources
will complicate the accuracy of predictions. Finally, the interactions of
the pollutants as they travel through the watershed may alter the pollutant
species to such an extent that identification of their origin may be diffi-
cult.
3.5.4 Stream sampling techniques for prediction:
Location of sampling sites: Where conditions permit at
least two sites must be selected, one upstream and one downstream of the
potential source suspected of contributing nonpoint pollution. These
sites must be as close as possible to preclude contributions from other
potential sources.
Parameters to be monitored: Only those parameters which
are most likely to contribute to the evaluation of agricultural pollution
should be monitored. These parameters may include flow rate, pH, tempera-
ture, turbidity, suspended sediment, dissolved oxygen, chemical oxygen
demand, phosphorus, nitrogen, coliform MPN, and specific conductance.
Other important parameters which should be selectively monitored include
pesticides, salinity measurements, biochemical oxygen demand, and fecal
coliforms.
79
-------
Frequency and duration of sampling: Since the runoff rate
and concentration of dissolved and suspended materials vary during any
given runoff period, samples are required periodically throughout the
runoff period. Because the greatest changes in rates of runoff and trans-
ported materials occur during the rising stages of the hydrograph, samples
must be collected more frequently during this period than on the recession
side (Figure 3-16). Thus, the sampling equipment must be capable of
collecting individual samples at predetermined time intervals throughout
the runoff hydrograph.—' Operating procedures and other design features
of the system are contained in the USDA publication ARS 41-136, which
should be consulted for further details.—'
Recently, Dissmeyer—' has proposed a method of estimating
the impact of different land use practices on stream water quality. Al-
though his method is applicable to forest land and aims specifically at
sediment yields in watersheds, the general principles of the method may
be extended to farmland pollution of sediments. A detailed discussion of
Dissmeyer's method is presented in Section 4, "Silviculture," of this
report. It must be recognized, however, that relating other pollutants
such as nutrients and pesticides to specific sources remains to be demon-
strated in this method.
80
-------
I/sec (c.f.s.)
28.3 (1.0)
22.7 (0.8) -
17.0 (0.6) -
Runoff Rate
11.3 (0.4) -
5.7 (0.2)
0
Sediment Concentration
(Ib/ft3) kg/m3
(0.5) 8.0
(0.4) 6.4 c
o
(0.3) 4.8 o
0 3 6 9 12 18 24 30
Sampling Times (Minutes)
(0.2) 3.2
(0.1) 1.6
0
O
.»—
c
0)
-------
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101. Viets, Jr., F. G., and R. H. Hageman, "Factors Affecting the Ac-
cumulation of Nitrate in Soil, Water, and Plants," USDA - ARS,
Agriculture Handbook No. 413 (1971).
102. Viets, Jr., F. G., "Water Quality in Relation to Farm Use of
Fertilizer," Bio Science, 21(10), p. 460, 15 May 1971.
103. Viets, Jr., F. G., "The Mounting Problem of Cattle Feedlot Pollu-
tion," Agri. Sci. Review, ,9/1), first quarter 1971.
104. Viets, Jr., F. G., "Fertilizer Use in Relation to Surface Water
and Groundwater Pollution," Fertilizer Technology and Use,
Second Edition, Soil Science Society of America (1971).
105. Viets, Jr., F. G., "Soil Use and Water Quality—A Look Into the
Future," Agricultural and Food Chemistry, 18(5), p. 789, September-
October 1970.
106. Volk, G. M., "Efficiency of Various Nitrogen Sources for Pasture
Grasses in Large Lysimeters of Lakeland Fine Sand," Soil Sci.
Soc. Am. Proc., 20:41 (1956).
107. Wadleigh, C. H., "Wastes in Relation to Agriculture and Forestry,"
USDA Misc. Pub. No. 1065, March 1968.
108. Walker, W. H., T. R. Peck, and W. D. Lembke, "Farm Groundwater
Nitrate Pollution—A Case Study," Preprint No. 1842, ASCE National
Meeting, Houston, Texas, October 1972.
109. Walker, K. C., and C. H. Wadleigh, "Water Pollution From Land Run-
off," Plant Food Review, 1 November 1968.
110. Weidner, R. B., A. G. Christiansen, S. R. Weibel, and G. G. Robeck,
"Rural Runoff as a Factor in Stream Pollution," J. WPCF, j41_(3),
Part 1, p. 377, March 1969.
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111. White, R. K., and W. M. Edwards, "Beef Barnlot Runoff and Stream
Water Quality," Waste Management Research, p. 225 (1971).
112. White, A. W., A. P. Barnett, and W. A. Jackson, "Nitrogen Fertil-
izer Loss in Runoff from Cropland Tested," Crops and Soils
Magazine, January 1967.
113. Williams, J. R., and H. D. Berndt, "Sediment Yield Computed with
Universal Equation," J. Hyd. Div., Proc. ASCE, No. 9426, p. 2087,
December 1972.
114. Williford, J. W., T. C. Tucker, R. L. Westerman, and D. R. Garden,
"The Movement of Nitrogenous Fertilizers Through Soil Columns,"
EPA Water Pollution Control Research Series 13030 ELY 12/69 (1969).
115. Willrich, T. L., and G. E. Smith, Eds., "Agricultural Practices
and Water Quality," WPCR Series - 13040 EYX 11/69, November 1970.
116. Wischmeier, W. H., "Estimating the Cover and Management Factor for
Undisturbed Areas," Purdue Journal Paper No. 4916, ARS, USDA.
117. Wischmeier, W. H., C. B. Johnson, and B. V. Cross, "A Soil Erodi-
bility Nomograph for Farmland and Construction Sites," J. Soil
and Water Cons., 26_, pp. 189-193 (1971).
118. Wischmeier, W. H., and D. D. Smith, "Predicting Rainfall-Erosion
Losses from Cropland East of the Rocky Mountains," Agriculture
Handbook No. 282, ARS-USDA, May 1965.
119. Woolhiser, D. A., "Deterministic Approach to Watershed Modeling,"
Nordic Hydrology II, pp. 146-166, Munksgaard, Copenhagen, Denmark
(1971).
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4.0 SILVICULTURE
4.1 Introduction
The gross area of the 50 states of the U.S. is about 916
million hectares (2,264 million acres). Over one-third of this is
covered with forests. Approximately 677o of the forests are classified
as commercial forests, totaling 203 million hectares (500 million acres),
of which approximately 27 million hectares (67 million acres) are in
private industrial ownership, 41 million hectares (100 million acres)
in public ownership, and the rest in private, nonindustrial ownerships.
Depending on natural and land use characteristics, these lands may
produce substantial quantities of pollutants to surface and underground
waters.
An established, well managed forest can be remarkably resistant
to emission of pollutants to the aquatic environment. Incident rainfall
is deprived of most of its erosive force by the tree cover, and rates of
infiltration through ground cover and into subsurface soils are often
high enough that intense rainfall can be accommodated without runoff
and the accompanying carry-off of silt by erosion. Such a forest has
the attributes popularly decreed to be necessary and desirable, as well
as technically and economically sound. Many forests do indeed possess
such attributes, and are at the same time useful, productive entities.
Productivity can be maintained over the long term with assistance from
man, which necessarily includes harvest of trees. A silvicultural cycle
includes a relatively long period of growth which can be essentially
free of pollutional output, and a relatively short period of harvest and
reforestation, which, as a result of disturbances, can be a time of high
pollutional output.
Disturbances to the forest come from nature as well as from
man. Disease, insects, windstorms, droughts, and fires can devastate a
forest, and degrade it to a polluting condition. Silvicultural activities,
which are generally concerned with timber production, with prevention of
natural devastation, and with restoration to a state of health and produc-
tivity, consist of harvesting, reforestation, growth promotion, disease
prevention, fire fighting and fire prevention.
The principal sources of pollution from forests thus are dis-
turbances which are natural in origin or are caused by man. The major
types of pollutants from forestlands are sediment, organic matter, applied
forest chemicals (pesticides, fertilizers, fire retardants), plant nutrients,
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and pathogens. Thermal effects on streams from solar radiation associated
with the reduction of shade from streamside vegetation are, in some cases,
pollutional.
This section summarizes findings relative to the identification
and evaluation of pollution from forestlands. The section initially gives
a review of silvicultural practices, both those now in use and potentially
future processes; and proceeds to enumeration of specific sources and
practices which effect pollution of water. The characteristics of prac-
tices and sources pertinent to their impact on the aquatic environment
are presented in terms of major types of pollutants, and how these pollu-
tants move from the forest to surface and groundwater, how natural and
operational factors affect relationships between inputs from the sources
and pollution levels in waters, and in some cases, to what extent
the pollutants have deteriorated water quality. Finally, a procedure
for quantification of pollution from silvicultural activities is
presented in terms of estimation methods, and a general approach to
sampling and monitoring of water quality.
4.2 Silvicultural Activities
4.2.1 Overview: Silviculture is defined as the theory and
practice of controlling forest establishment, composition, and growth.—'
It is a continuous management process that begins when mature timber is
harvested and the site is prepared for a new crop of trees. Depending
on the region, type of species, topography, and method of regeneration,
etc., the forester might be required to burn excess slash, dip- the site,
or use some other technique to prepare the area for reforestation and
a new crop of trees.
As the forest begins to develop, overstocking might be a problem.
In that case, a precommercial thinning may be necessary to remove poorer
quality growth and provide growing space for the best stems. On the
other hand, understocking might require planting open spaces to assure
full utilization of the site. Later, as the stand begins to reach mer-
chantable size, a thinning might be made to remove products such as
poles, pilings, pulpwood, and fence posts. The main purpose of thinning,
however, is to provide growing space for the best quality trees.
As the forest grows, a forester will provide protection and
maintenance to the timber stands. This may come in the form of insect
spraying, prescribed burning, application of fire retardants, and other
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physical or biological techniques that will assure that the stand will
be available for harvest at the end of the rotation.
In forest management, the appropriate silvicultural system
is selected which will assure optimal productivity of desirable tree
species. A harvest system to achieve these objectives is then selected
and implemented. A primary log transport (yarding) method is used to
remove logs from the felling location to a landing or transfer point.
The method should be economical, minimize damage to the site and provide
site conditions compatible with species restocking requirements. Each
stand must be tied to a series of roads so that a balanced, long-range
management program can be achieved.
4.2.2 Harvesting systems: The harvesting methods recognized
by the forestry profession in the United States are the clearcut, seed-
tree, shelterwood, and selection systems.—These methods are based on
ecological and economic considerations for the desired tree species.
The ecological factors that are considered in the selection
of a harvest method include the silvical requirements of the favored
timber species, the relationship between the forest and wildlife, poten-
tial insect and disease problems, the impacts of fire and climatic
hazards, the vigor of the timber stand, and the potential for using
artificial reproduction methods.
Economic factors are also weighed in the selection of a harvest
system. These include the availability of markets, management and har-
vesting costs, value of the product, and future costs of protection and
maintenance. Each of the harvesting methods are discussed in the follow-
ing sections.
(a) Clearcutting: This is a method whereby virtually
all trees are removed in the harvesting process. It lays bare an area
for the establishment of a new even-aged forest. Clearcutting is par-
ticularly adapted to subclimax species that do not reproduce well under
low light intensity and strong competition for soil moisture. It is also
adaptive to the prompt establishment of genetically improved stands
through artificial reforestation. The principal species that are har-
vested by Clearcutting are shortleaf pine and loblolly pine in the South;
red pine and jack pine in the Lake States; red spruce, white spruce, and
balsam fir in the Northeast; lodgepole pine in the Rocky Mountains; and
Douglas fir in the Pacific Northwest.
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Clearcutting may range in size from a few acres to many
hundreds of acres. It may be done in strips, patches, or over entire
watersheds. If not properly planned and executed, clearcutting may
lead to serious water pollution problems by the acceleration of sediment
production.
(b) Seed tree: Harvest by this system removes all trees
on an area with the exception of a few of the most desirable trees that
are left to produce seed and restock the cutover area. When sufficient
reproduction is established, the seed trees are then harvested. The
method is especially adapted to light-seeded species that require mini-
mum competition and bare mineral soil for establishment. The seed tree
method is used to harvest the longleaf, loblolly, slash, and shortleaf
pine types in the South. Next to clearcutting, the seed-tree method
probably has the highest potential of releasing sediment into streams.
(c) Shelterwood: Application of this method, which
currently has very limited application, involves gradual removal of an
entire stand in a series of partial cuttings extending over a fraction
of the rotation. Under intensive forest management, these cuttings
resemble heavy thinnings. The main difference between the shelterwood
system and the two previously discussed methods is that establishment
of a new crop is accomplished before the final harvest removal. This
system is used on flatter ground where track or wheel yarding tractors
can operate easily. The system may require a great amount of skid trails
and roads. Heavy-seeded and intermediately tolerant species are well
adapted to the shelterwood harvest system. The following forest types
may be harvested by this method: the Appalachian hardwoods, the Central
hardwoods, and Eastern white pine and red pine types in the Lakes States.
(d) Selection: The selection system is applicable only
where it is desirable to maintain an all-aged forest. The oldest or
largest trees are removed at periodic intervals of 5 to 20 years. Any
one harvest would normally remove less than one-third of the total stand.
The selection system is adapted to tree species that are tolerant and
will reproduce under dense shade and competition for moisture and
nutrients. The system is normally restricted to flatter ground where
track or wheel vehicles can operate. On steep ground the system requires
a higher intensity of skid trails and roads than other systems.
4.2.3 Log transport methods: After trees are felled in a
logging operation, they are collected into a yarding area where they
are loaded into trucks. The logs are then transported to the mill via
permanent roads. In a few cases in New England and the West, logs are
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rafted from yarding areas to the mill on streams or rivers. For the
purpose of this report transport is defined as the movement of logs
from the point of felling to a permanent road. This is usually described
in logging terminology as skidding, yarding, or snaking operations. This
section identifies the pollution potential of the following methods of
log transport: tractor, high lead, skyline cable, balloon and
helicopter.
(a) Tractor: Tractor skidding can be done with either
four-wheeled tractors or crawler tractors. A winch may be used to snake
logs to the tractor before skidding them to the yarding area. Two
improvements are often used to minimize scarification of the site--a
skid pan and a high-wheeled arch yarder.
Tractor skidding is the most common method used in the
Northeast and South, and on lands with less than 307, slope in the Inter-
mountain, Northwestern and California regions. Even on level to rolling
land, however, tractors can expose more bare soil than other methods of
log transport.
(b) High lead: The high lead log transport system is
adapted especially to clearcutting. A metal tower about 23 meters
(75 ft) high is mounted on a mobile frame. Guy lines hold the tower
in place, and a winch and set of cables at the tower drag the logs along
the ground to a yarding area, where they are loaded into a truck. The
pollution potential is generally less than for tractor skidding, although
when logs are repeatedly yarded over a high spot on the ground, profile
deep cuts into the soil may occur.
(c) Skyline cable: This method employs a cable to carry
the full weight of the logs as they are transported. Aerial cables are
attached to the towers which are constructed at the opposite ends of the
logging sites, and logs are mechanically lifted off the ground and moved
along the cable to the landing area- The landing area is usually near
the base of one of the towers. Logs may be moved to the top or to the
bottom of a drainage slope in order to yard logs near a permanent road.
Since a large volume of timber is required to justify this
type of setup, the method is used principally on clearcut logging opera-
tions. There is less potential for pollution from this method because
fewer temporary logging roads are usually required. Herman reported
that skyline cable logging requires only one-tenth as much road construc-
tion as more conventional methods such as tractor and high lead.— Logs
are also lifted off the ground, thereby avoiding cuts on the forest floor.
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The system can operate at distances of more than 900 m
(3,000 ft). Cables should be installed at a height that will insure
that logs are lifted off of the ground during most of the transport
operation. Soil disturbance is then confined to yarding and loading
areas.
(d) Balloon: This method employs a large balloon usu-
ally filled with helium and capable of static lifts of 4.5-9 metric
tons (5-10 tons). A cable system similar to high lead is used to control
the horizontal movement of the balloon over the logging site. A snubbing
line may be required to winch the unloaded balloon close to the ground.
The static and dynamic lifting forces hold the logs off the ground dur-
ing yarding. Balloon logging is adapted to steep slopes (45 to 907«)
where clearcutting is used on unstable soils. A minimum of 70 m^ per
hectare (12,000 board-feet per acre) is necessary to justify this type
of log transport.—'
Balloon logging causes soil disturbance and erosion only
at the landing areas where the logs are loaded into trucks. Landing or
yarding areas can be as far as 900 m (3,000 ft) apart. Balloon logging
is more expensive than most other logging systems.
(e) Helicopter: Using a helicopter, logs are lifted
from the ground at the point of felling and transported to the loading
area. Binkley— found, in studies in the Pacific Northwest, that heli-
copter logging required fewer access roads, was more expensive (direct
variable cost) than other methods, and that it was a very versatile system
for moving logs from felling sites to loading areas. Binkley suggested
that helicopter logging be used to transport valuable timber in inac-
cessible areas where managing for aesthetic values has high priority.
4.2.4 Regeneration: The regeneration process differs sub-
stantially for different regions and types of forests, and the harvesting
method is usually geared to favor propagation of desired tree species.
Several types of regeneration methods are discussed briefly in the
following subsections.
(a) Tree planting: Tree planting on clearcut areas,
understocked areas, and burned areas, is an increasingly common practice.
Numerous governmental agencies and the private forest industry have led
in this activity. Scientific guidance is available to enable the
establishment of productive forests in marginal areas as well as areas
suitable for high yield timber production. Since 1930, 14.7 million hec-
tares (36.3 million acres) of land in the U.S. have been planted with trees.
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(b) Natural regeneration: Natural regeneration to
establish productive stands of preferred tree species is best obtained
when the forest practice is set up to provide favorable conditions for
natural germination and growth of desired seedlings. The method of
harvest is an important factor in establishing the required conditions.
The seed-tree method is suitable for propagation of selected southern
pine species. The shelterwood system of harvest is well adapted to
regeneration of Appalachian mixed hardwoods. The selection system is
adapted to propagation of species such as Engelmann spruce and alpine
fir in the Rocky Mountains and ponderosa pine in the West. The clearcut
harvest method is suitable for establishment of uniform stands (even-
growth) of intolerant species that do not reproduce readily under com-
petition from other trees: southern pines, Douglas fir in the Pacific
Northwest, and western white pine in northern Idaho are among the classic
species which achieve satisfactory reproduction from clearcut areas.
(c) Influence of fire on regeneration: Forest wildfires
have historically played an important role in natural regeneration and
maintenance of preferred tree species. Hendrickson-Lt/ has stated that
from studies of tree rings, the frequency of fires in various types
of forests are shown in Table 4-1.
TABLE 4-1
FREQUENCY OF FOREST FIRES NECESSARY TO MAINTAIN SPECIES
FOR .UNMANAGED FORESTS^/
Tree Species Requiring
Fire to Maintain Themselves Frequency of. Fires
in a Forest (years)
Slash pine, longleaf pine 3-18
Ponderosa pine, pitch pine 12-25
Douglas fir 25-50
Quaking aspen 50-100
Lodgepole pine, jack pine 100-300
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As the art of silviculture has advanced, the use of fire
has been beneficially applied, and in recent years use of prescribed
fires in silvicultural activities is a scientifically accepted practice.
Prescribed burning is extensively employed in some areas to reduce poten-
tial wildfires by systematically preventing the surface buildup of fuel
resulting from slash and other forest debris. Traditionally it has
been an accepted silvicultural practice to remove surface vegetation by
a process of controlled burning to permit direct contact of seed from
intolerant tree species with mineral soil.
4.2.5 Intermediate practices: Certain practices are employed
primarily for the benefit of the growing forest. Chemical pesticides
are used for control of insects, weeds and weed trees, plant diseases
and rodents. The application of chemical fertilizers has been a new
practice for increasing unit growth increments. The use of fire retard-
ants to control or manage fire is an essential practice in silviculture.
Prescribed burning may also be an intermediate practice.
4.3 Nature and Extent of Sources of Pollution from Silvicultural
Activities
4.3.1 Overview: Pollutants from silvicultural activities are
similar to those generated by agriculture. The most important pollutant
originating from silvicultural activities is sediment. Sediment is
eroded and transported to surface waters by the action of runoff and
rainwater. Excessive quantities of sediments degrade water quality phys-
ically, chemically and biologically. Sediments are carriers of pesti-
cide residues and nutrient elements, and are significant pollutants for
this reason.
Thermal pollution from solar radiation can be a result of
silvicultural activities. Although deviations from "normal" temperatures
in surface waters are considered pollutional, thermal pollution involves
only the elevation of temperature above a norm. Thermal pollution in
forests results from the removal of tree cover which protects streams
from solar energy. Surface water temperatures may become substantially
higher when exposed to direct sunlight.
Organic matter of vegetative and animal origin is likewise
transported to surface waters by runoff. The organic matter ranges
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from green vegetative refuse through well-decomposed humic matter.
The organic matter sometimes has a high nuisance value (floating debris);
sometimes physically interferes with normal aquatic ecology (bark depos-
ited in spawning beds); and nearly always becomes involved in biochemical
processes which are nature's way of degrading organic matter, and which
can markedly alter chemical/biological balances in an aqueous ecosystem.
Pesticides used in silviculture are potential water pollutants.
Insecticides, fungicides, herbicides (silvicides) and rodenticides used
to protect forests may be deposited directly in surface water courses
by careless application, or be transported thereto in surface runoff.
Pesticides differ from other pollutants in that the great majority of
pesticides used in silviculture are not materials native to the forest
environment. Pesticides, furthermore, are toxic, by design, to some part
of the environment in the accepted mode of use. Evaluation of pesticide
pollution is a more complex issue than the evaluation of other forest
pollutants. Analyses of the pollution potential require a knowledge
of: persistence of the pesticide at the point of use; rates of degrada-
tion; modes of degradation and identities of biological and chemical
metabolites; mechanisms of transport through the environment to nontarget
species for those pesticides that are not biodegradable; and knowledge
of toxicity to nontarget species.
Fertilizers and fire retardants contribute nutrient elements
to the forest environment. These elements, primarily nitrogen and phos-
phorus, can be transported overland to surface waters in runoff and to
both surface and groundwaters by infiltration through ground cover and
subsurface soils and mineral formations. In addition to the contribu-
tions from fertilizer and fire retardant application, nitrogen, phos-
phorus, and other nutrients can also be added to streams from the cutting
and burning of forests--because these activities interrupt the natural
nutrient cycling of the forest ecosystem. Among these nutrients, nitrogen
is a "water soluble" element in both the reduced (ammonia) and oxidized
(nitrate) forms, and is much more susceptible to transport in runoff
water and infiltrating water than is phosphorus. Ammonia is toxic to
fish at the part per million concentration range. The nitrate ion is
toxic under certain conditions. Phosphorus is chiefly noted for its
accelerating role in eutrophication processes. Both nitrogen and phos-
phorus are highly essential elements present naturally in abundance--
they become pollutants when their presence causes adverse effects on
the aquatic environment.
Bacteriological pollution of surface water from forestlands
can originate from soil, plant and tree debris, and, most importantly,
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animal and human wastes. Pathogenic agents emitted from these sources
may subsequently infect animals, or in case of some disease producing
agents, humans.
4.3.2 Sediment: Sediment is produced from erosion of soils.
Three major erosion processes are of concern in forestlands: surface
erosion, mass soil movement, and channel erosion. Surface erosion is
the direct result of rain striking unprotected soil surfaces, detaching
soil particles, and transporting them by overland flow across the soil
surface. Mass soil movement is the process by which large volumes of
soil and rock materials move downslope under the influence of gravity.
Channel erosion is the result of abrasion by water or debris on stream
bank and stream bed.
Silvicultural activities may accelerate soil sediment produc-
tion through influencing all three processes: surface erosion, mass
soil movement, and channel erosion. This subject has been reviewed in
detail by Brown.—'
(a) Surface erosion: Surface erosion in forestlands is
affected by the following natural and man-caused factors:—' road con-
struction, logging, fire, and grazing. These factors conbribute to
soil erosion by exposing surface soil to the erosive effects of rainfall
and runoff.
The impact of raindrops causes the detachment of soil
which is unprotected by vegetation or litter. Soil detachment is the
principal effect of the transfer of kinetic energy from raindrops to
soil mass. The detaching ability of rainfall depends on raindrop size
and velocity and on rainfall intensity. It has been estimated that rain-
fall of 5 cm (2 in.) an hour generates 458 kw/hectare (250 hp/acre),
enough to lift 18 cm (7 in.) topsoil layer to a height of 0.92 m
(3 ft) about 86 times.—'
Surface erosion results when precipitation exceeds the
infiltration capacity of forest floor materials and underlying soils.
When soil particles are exposed by raindrops, they are subject to
detachment and the structure of the soil is altered. Large pore
characteristics of many forest soils become clogged, thus sealing the
surface and reducing the infiltration rates, which are normally high.
Rainfall which should have infiltrated now becomes runoff and overland
flow.
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Mechanical compaction of surface soil by machines or
animals also may reduce infiltration and produce surface runoff. When
combined with vegetation removal, mechanical compaction may result in
extremely high erosion rates on certain soils and slopes for a short
period of time.
Physiographic factors of surface soil may influence
soil erosion directly or indirectly. Steepness of slope and length of
slope directly influence erosion through their influence on the velocity
of surface runoff. Since velocity increases with the square root of
slope, and the sediment-carrying ability of water increases with the
sixth power of the velocity, one might expect the sediment-carrying
potential of surface runoff to increase with the cube of the slope.
Elevation and aspect affect soil erodibility indirectly through their
influence on soil development. Willen—'compared the erodibility of
granodiorite soils at elevations over 2,160 m (7,000 ft) with similar
soils at elevations of 600 m (2,000 ft). He found that the high ele-
vation soils were potentially 2.5 times more erodible. A similar rela-
tionship might be expected where aspect limits soil development.
As soil development proceeds, a larger proportion of
surface soil particles are combined into water stable aggregates. Thus,
those factors which influence soil development should influence struc-
tural stability and aggregate size and thereby the resistance of soil
to erosion by water. Major factors which influence soil development
are discussed below.
• Parent material: Many forest soils are shallow,
immature and therefore poorly developed. Their characteristics are
often closely related to the parent rock. In the West, several types
of rock give rise to highly erodible soils. Among these are the acid
igneous rocks, such as granite and granodiorite. The degree of aggrega-
tion and the aggregate stability of soils derived from these parent
materials are quite low. Flocculation and dispersion of soil colloids
are related to the absorbed cations present in the soil. The cations,
in turn, are derived from the weathering of parent rock. The parent
rock, therefore, also determines the nature of the chemical bonding
within the soil matrix. The low fertility of these soils generally
results in low plant density and a lower organic matter content of the
soil.
• Climate: Climate, particularly moisture and
temperature, strongly influence the rate and extent of soil development.
Temperate, moist sites favor rapid breakdown of parent materials and
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consequent soil development. Wetting and drying cycles, as well as
freezing and thawing, influence aggregate development by accentuating
lines of shear within the soil and by mixing soil particles.
• Biologic activity: Biologic activity favors soil
development and resistance to erosion. Earthworms and plant roots mix
and disrupt the soil matrix. Acidic by-products of microbial decom-
position and leachate from plant litter help decompose parent materials.
Organic materials act as an important cementing agent in the formation
of aggregates from primary soil particles. Organic matter may also
influence aggregation by an electrochemical bonding in much the same
manner that clay minerals interact. Generally, the higher the organic
matter content, the larger the aggregate size, and the less erodible
the soi.\.—l
• Time: Time is required for soils to develop from
the parent rock. The absolute rate is a function of climate, parent
material, living organisms, and topography. The relative degree of
development, however, is related to the time since the soil forming
process began. Thus, soils formed on newly-deposited pumice or lava
would probably be less well developed than soils developing on ancient
lava flows.
• Physiography: Physiography influences soil develop-
ment in several ways. One of the principal ways is through its influence
on microclimate. Slope, aspect, and elevation modify the radiation,
temperature, and moisture levels of the general climate. As a result,
weathering of parent material and composition of plant communities may
also be modified.
Construction of roads, skid lanes, and fire lanes,
harvesting, fire, and grazing in forestlands may contribute to soil
erosion by exposing surface soil to the erosive effects of rainfall
and runoff.
(i) Skid lanes and fire lanes: Roads are conceded
to be one of the principal sources of soil sediments from forestlands.
Logging roads ordinarily are constructed prior to the logging operation.
They provide access for equipment, and serve as routes for transport
of logs out of the forest. Skid trails are the disturbances created by
hauling logs from the freshly cut area to yarding areas or roads. Fire
lanes are established, either permanently or temporarily, but cutting
stands to prevent expansion of forest fires.
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The mineral soil surfaces of logging roads, skid
trails, and fire lanes, are exposed and compacted, and have little
capacity to absorb runoff during storm events. Such runoff not only
causes erosion on the road surface, but also initiates erosion in less
disturbed areas.
Forest roads that are improperly designed and con-
structed are often the main cause of high sediment content in streams
flowing through forested watersheds.
The effect of road construction on the extent of
soil erosion and sediment production is dependent on numerous natural
factors and man's activities involved. In the following paragraphs,
results are presented from specific research experiments in various
parts of the United States. Because of the complexity of the subject,
no generalization can be made from the relatively small number of experi-
mental studies.
In central Idaho, Megahan and Kidd— reported that
sediment production in streams primarily resulted from the construction
of logging roads, and that nearly 847o of all sediment was produced dur-
ing the first year after construction. An additional 9% was generated
during the second year, and about 270 or less each year for the next 4
years.
80/
At Castle Creek in California, Rice,— and Anderson
and Wallis— showed that sediment resulting from construction of roads
O f\
in a 10 km (4 mile ) watershed increased the average sedj-nent concentra-
tion and sediment yield by fivefold in the first year: from 64 ppm to
303 ppm, and from 326 metric tons/km/year (935 tons/mile/year) to
1,610 metric tons/km^/year (4,600 tons/mile/year). In the second year,
concentrations and yields declined to twice the normal rate.
Properly planned and managed road construction will
result in greatly reduced erosion. A study in West Virginia by Reinhart—
showed that a well planned logging operation produced a maximum turbidity
of 25 JTU (Jackson Turbidity Unit), while in an adjacent watershed,
tractor-logged without plan or direction, maximum turbidities of 56,000
JTU were recorded.
In Alaska, sediments may result from fire lanes con-
structed in areas of low relief if the soil is fine textured. Bolstad-
has indicated that when the organic protective covering is removed, the
105
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shallow permafrost melts, and surface water starts to flow downward and
laterally, to cause surface soils nearby to collapse. Silts and clays
then move through ice caverns to accelerate the process of erosion and
soil sediment deposition in nearby streams.
(ii) Harvesting; Disturbed forest litter and exposed
soil resulting from harvesting and logging are the principal sources of
sediments in a harvested area. The harvested area is susceptible to
erosion until new vegetative cover is established. Harvesting in com-
bination with log transport may result in varying degrees of damage to
the forest floor. Rice, et al.,—' who reported data (Table 4-2) on
effects of log transport and harvesting systems, found that clearcutting
by the balloon system of logging resulted in the lowest soil sediment
load deposited in the streams. Using this method only 6% of the logged
area was made bare to mineral soil. In contrast, clearcutting by tractor
laid bare 29.4% of the logged area.
TABLE 4-2
PERCENTAGE OF SOIL IN LOGGED AREA MADE BARE BY VARIOUS
LOGGING SYSTEMS IN WASHINGTON AND OREGON
Portion of
State(s)
Eastern Washington
Western Washington
Eastern Washington and Oregon
Eastern Washington and Oregon
Western Oregon
Western Oregon
Western Oregon
Eastern Washington
Western Oregon
Western Oregon
Logging System
Tractor (clearcut)
Tractor (clearcut)
Cable (selection)
Tractor (selection)
High lead (clearcut)
High lead (clearcut)
Skyline (clearcut)
Skyline (clearcut)
Skyline (clearcut)
Balloon (clearcut)
Percentage of Soil
in Logged Area
Made Bare
29.4
26.1
20.9
15.5
14.1
12.1
12.1
11.1
6.4
6.0
106
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Results of field studies seem to indicate that
clearcutting itself may be less damaging than the roads necessary for
access to the logging site. In studies where trees were clearcut and
left in place, no increases in sediment occurred during the first
year, but stream flow increased 657°.—'
Likens, et al.,—' also reported no increase in
turbidity following clearcutting on a New Hampshire watershed. In
this study trees were not removed from the watershed, but remained on
the ground.
13/
In the Northwest area, Brown and Krygier— studied
a clearcut by high-lead system in a 15 hectare (39 acre) watershed
and reported that no measurable increase in suspended sediment was
?Q /
observed. Fredricksen—' reported that on a watershed clearcut over a
3-year period with a skyline system, sediment concentrations were only
modestly affected. Mean concentration during storms remained below
10 ppm.
Lynch,et al.j— conducted a watershed study in
Pennsylvania. The watershed was clearcut and logged carefully with little
disturbance of the soil surface. Suspended sediments were measured
throughout 4 years after treatment on the clearcut and uncut forests.
During the first year, the mean concentration was 6 times greater
(16.5 ppm compared to 2.7 ppm) and the maximum 14 times greater (72 ppm
to 5.3 ppm) on the clearcut than on the uncut forest. These differences
in concentration became negligible during the next 4 years.
25 /
Eschner and Larmoyeux— demonstrated that in West
Virginia there was a direct and positive relationship among the harvest-
ing method, the percentage of harvested area in bulldozed roads, and
the maximum stream turbidity. Turbidities of streams varied from 15
JTU for areas not logged and where no roads had been built, to 56,000
JTU under clearcut regions where 3.67o of the area logged was in roads.
(iii) Fire: Fire in forests may subsequently accel-
erate soil erosion: (1) fire consumes vegetation, litter and duff
materials, and leaves soils unprotected against the impact of raindrops
and runoff; (2) removal of soil surface protection reduces evapotrans-
piration and increases water available for surface erosion; (3) hot
fires may reduce the organic content of soil and alter the stability of
surface soil aggregates; (4) hot fires may reduce infiltration rates
107
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and increase surface runoff on many soils by production of a non-
wettable surface layer. All these elements increase the susceptibility
of soil to water erosion after forest burning.
Prescribed burning has been used, especially in the
South, by silviculturists since the turn of the century. This practice
is used: (1) to reduce the fuel accumulation, and therefore, the hazard
of very hot and uncontrollable wildfires; (2) to control undesirable
species of trees such as oaks in an oak-pine forest; (3) to improve the
habitat for wildlife; (4) to prepare a seedbed for natural reseeding
and for planting of pines; (5) to enhance grazing; (6) to control the
brown spot fungus disease of longleaf pine; (7) to increase volume
growth of trees.
The effect of forest fire on soil erosion varies
with factors such as soil type, rainfall pattern, and topography. For
each case, evaluation of such effects should be based on the specific
factors involved.
Ralston and Hatchell—have reported on comparative
soil erosion losses from burned and unburned forests in the South. In
five locations studied, soil erosion was greater in the areas treated
by prescribed burning, by factors ranging from 7 to 1,500.
13/
Brown and Krygier—— reported a large increase in
sediment yield after a very hot slash fire in a 70 hectare (175 acre)
clearcut watershed in Oregon. Sediment yield increased about threefold
after road building and about fivefold after logging and burning, over
the value expected for the undisturbed area. Higher than normal sediment
yields persisted for 3 years after logging and burning, but declined
during the following years as vegetation returned.
Wildfires also leave forestlands in a state sus-
33 /
ceptible to erosion. Glascock,— who presented the data shown in
Table 4-3 on causes of wildfires, concluded that erosion induced by
uncontrolled forest fire is greater than that induced by prescribed
burning.
Copeland—reported the effect of an extensive
wildfire on sediment yields from two small experimental watersheds in
Nevada. Shortly after the fire, a high intensity thunderstorm occurred
for a duration of 30 min. The completely burned watershed produced
about 44 nrVhectare (630 ft-Vacre) of sediment, while another watershed,
only partially burned, yielded 23 m3/hectare (338 ft3/acre).
108
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TABLE 4-3
CAUSES OF WILDFIRES—
Percentage
Cause of Wildfire of Total
Lightning 35
Incendiary 21
Debris burning 16
Campfires 8
Miscellaneous 7
Smoking 6
Equipment use 6
Railroads 0.5
Children 0.5
Total 100.0
97
(iv) Grazing:— Overgrazing may result in serious
erosion problems. Heavy grazing may lead to rapid deterioration of
vegetative cover, particularly in areas with sparse vegetation, short
growing seasons, shallow and poorly developed soils, and occasional
drought. Under this condition, rainstorm runoff will cause severe
erosion. CopelandiS/ reported that thunderstorms in a summer carried
72,900 m3/km2 (153 acre-ft/mile2) of sediment from a 555 hectare (1,378
acre) watershed, where vegetation was destroyed in only 12% of the area.
A nearby undamaged watershed produced sediment at 1.19 m-Vkm2 (0.0025
acre-ft/mile2).
(b) Mass soil movement: Mass soil movement is the down-
slope movement of a portion of the land surface under the effect of
gravity. Such movements may take the form of landslide, mud flow, or
109
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downward creep of an entire hillside, and may constitute the dominant
process of erosion in areas with exceptionally steep slopes, high rain-
fall, or low-strength soil, such as that of mountainous areas of western
North America. In such areas, soil may remain in place as the result
of a delicate balance between forces tending to cause downslope movement
and the various forces tending to resist it. Any disturbance may upset
this delicate balance and result in initiation or acceleration of mass
^/
soil movement.
The effect of mass soil movement goes far beyond increas-
ing stream sediment yields and turbidity. When large volumes of sediment
enter a small stream with a steep channel, slides may scour bed materials
to the bedrock base and eliminate productive aquatic comnunities. When
landslide materials are deposited in channels of gentler grade, they
may fill pools and cover the porous gravels used as spawning sites by
fish. In some instances, deposited materials may create a new bottom
environment which is incapable of supporting a stable aquatic community.
Landslide is influenced by the slope of the land, composi-
tion of soil, and water content of the soil. Dyrness^-' indicated that
stony soils from basalt and andesite were 14 to 37 times more stable
than those from tuffs and breccias, which are volcanic parent materials,
and normally weather rapidly to silts and clays. Silts and clays can
retain large quantities of water. The water adds to the soil burden
and reduces its strength, thus promoting landslides. In Oregon, land-
slides normally occur near peak stream flow from winter storm runoff
when water content of soil is at the maximum.
Silvicultural activities may play an important role in
initiation and acceleration of mass soil movements. Quantitative
relationships vary substantially from one situation to the next, and
research observations and conclusions must therefore be interpreted
with caution. Some of the research on this subject is summarized below,
with the above qualification in mind.
In a review of mass erosion research in the western United
States, Swanston^.' made the following statements about the effect of
disrupting activities on mass soil movements:
"Road building stands out at the present time as
the most damaging activity. Soil failures relating to
this activity are the result primarily of slope loading
from road fill and sidecasting, inadequate provision for
slope drainage, and bank cutting.
110
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"Fire, natural and man-caused, is a second major
contributor to accelerated soil-mass movement in some
areas. This relates largely to the destruction of the
natural mechanical support of soils, often abetted by
surface denudation of the soil mantle, thus opening it
to the effects of surface erosion.
"Logging, the third activity, affects slope stability
mainly through destruction of protective surface vegeta-
tion, obstruction of main drainage channels by logging
debris, and the progressive loss of mechanical support
on the slopes as anchoring root systems decay."
Croft and Adams— attributed increases in mass soil
movements in the Wasatch Mountains to los s of mechanical support for
root systems of trees and plants, resulting from logging and burning.
23/
Dyrnessrelated an apparent increase in mass soil
movement frequency to logging practices on the H. J. Andrew Experimental
Forest, Oregon. Krammer-t-^.' reported an increase in sediment production
from mass soil movements of 10 to 16 times following a wildfire in the
Gabriel Mountains of Southern California.
In the mountainous terrain of western Washington and
western Oregon, where conditions favor mud slides, Fredriksen=-^'
reported on a mud and rock slide in a watershed in Oregon that was being
monitored. Three thousand eight hundred cubic meters (5,000 cubic yards)
of debris slid down 900 m (3,000 ft) of a creekbed because of a combina-
tion of a newly-built logging road, excess rain and snow, and unstable
soils and geologic substrata. Mass slides tend to move downstream each
season when unstable conditions exist.
(c) Channel erosion: The bank and bed of a stream are
also important sources of sediment. These sources are highly sensitive
to disturbances, which will directly and immediately be reflected in
downstream turbidity levels.
Contributions of channel erosion to sediment discharge,
in some regions of the country, can be higher than those from other
sources, as indicated by two case studies. Anderson—' estimated the
following relative percentages of sediment contribution from stream
bank erosion, landslide, and land surface erosion for the north coast
watersheds of California:
111
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Percentage of
Source of Sediment Total Sediment
Streambank erosion 55
Landslides (soil and debris slides) 25
Land surface erosion 20
2/
Another comparison was made by Anderson— for the Willamette Basin of
western Oregon on sources of sediments from stream channel erosion,
forestlands, and agricultural lands, as follows:
Percentage of
Source of Sediment Total Sediment
62,600 m (205,000 ft) of eroding
main stream channels 54
14,160 sq km (5,460 mile2) of
forestlands 24
4,710 sq km (1,820 mile2) of
agricultural lands 22
One of the important causes of channel erosion in the forested
watershed is failure of debris jams, either natural or man-caused. When
debris jams fail, they release large quantities of water together with
logs, rocks and impounded sediment. The resulting torrent of debris
wears channel banks, exposing new bank surfaces for erosion, and scours
the stream channel.
Logging may greatly accelerate accumulation of debris. Fell-
ing may begin at the downhill cutting boundary, often a stream course,
and proceed uphill. In such cases, no barrier exists to downhill move-
ment of logging debris. The steeper the slope, the greater the prob-
ability of debris accumulation in the stream.
Meehan, et al.,— observed the accumulation of residues in
two Alaskan watersheds under patch cutting, and compared the residue
accumulation with unlogged watersheds. During 4 years, a 237o increase
112
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of debris in the stream was observed in one watershed in which about 207o
of the area was logged. In the second watershed, about 25% logged, debris
in the stream channel increased by 627,. During the same period of time,
an unlogged watershed nearby experienced 77, increase of debris accumula-
tion. Meehan, et al. ,— and Helmers— have shown that debris jams
trap sediment upstream and induce scour downstream.
4.3.3 Water temperature: Thermal effects on streams from
silvicultural activities are normally the increase of temperature due
to solar radiation. This is associated with the reduction of shade
cover caused by clearcutting along streambanks. Such effect can cause
a serious pollution problem in small streams during periods of low flow
in summer months.
Temperature is a significant water quality parameter. It
strongly influences dissolved oxygen concentration which affects
aquatic life and bacteria population in streams. Changes of temperature
can induce algae blooms, which subsequently induce changes in taste,
odor, and color of a stream. Increases of water temperature may enhance
the growth and development of many species of aquatic bacteria, some of
which are pathogenic to fish, such as the Chondrococcus columnaris
Increased populations of these bacteria may cause fish mortality.U
The saturated dissolved oxygen concentration is inversely
proportional to water temperature. In a stream, this means that the
higher the water temperature, the less dissolved oxygen is available
for aquatic organisms.
In addition to the effect on dissolved oxygen and aquatic
bacteria, water temperature is also a key control factor on fish growth.
In some cases, fish growth rate may increase by raising water temperature.
In most cases, however, lower temperatures are desired during the warm
part of the year, and an elevation of temperature constitutes pollution.
Low summer stream temperature is particularly important in
the Northwest, where the fingerlings of salmon and steelhead inhabit
the pools of small streams during the summer months. When stream tem-
perature becomes unfavorable, fingerlings may be isolated in these
pools, and unable to migrate when water levels fall.
Research results all point to the strong effect exerted on
water temperature when shade from streamside vegetation is reduced.
Border strips of uncut trees, shrubs, or logging slash will shade the
water and keep stream temperatures down. The nature of the effect is
indicated by case studies described below.
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Levno and Rothacher— conducted a research program on a 96
hectare (237 acre) watershed in the Cascade Range of Oregon. They
reported that logging of a watershed and burning of slash increased
maximum stream water temperatures above those on a watershed not logged
and not burned, by 7.2°C (13°F) in June, 7.8°C (14°F) in July, and 6.7°C
(12°F) in August. The maximum temperature recorded was 24°C (75°F)
during a 3-hr period in July.
Using data collected over a 9-year period on the Entiat
Experimental Forest in north central Washington, HelveyAI' reported
that the maximum summer temperatures of recently burned watersheds were
about 5.6°C (10°F) warmer than those of unburned watersheds. In winter,
however, stream temperatures of burned watersheds are approximately the
same as those of unburned watersheds.
Lynch, et al. ,— calibrated a forested watershed in Pennsyl-
vania for 7 years, then clearcut the lower one-third, and controlled
new growth with an herbicide. Stream temperatures were measured for
an additional 4 years. Winter temperatures were insensitive to water-
shed treatment, as were mean water temperature, partly because of the
presence of snow and ice. Mean monthly maximum temperatures, however,
were 3.3°C (6°F) higher on the clearcut area during June, July, and August.
4.3.4 Organic wastes: When materials such as tree leaves,
slash, and logs get into streams, they contribute organic pollutants.
Digestion of organic pollutants by microorganisms may cause dissolved
oxygen deficiencies for certain species of aquatic life such as fish.—'
Organic pollutants may also cause odor, taste, and color problems.
Ponce-^1 studied BOD exerted by needles of Douglas fir and
western hemlock and by leaves of red alder Rates of decomposition of
different materials varied. Leaves from the red alder in the Northwest,
the sugar maple in the North, and the tulip tree in the South,easily
decomposed and extracted oxygen from streams quite rapidly. By
contrast, needles from most coniferous species were decomposed by micro-
organisms more slowly, and thus did not rapidly deplete oxygen in
streams. Most slash and logs decomposed slowly.
The potential severity of pollution from organic wastes is
illustrated by research in the northwestern United States on a harvested
watershed in which dissolved oxygen dropped from 10 ppin to 1 ppm as a
result of increased BOD, damming by organic debris, and stream water
temperature increase caused by the direct rays of the sun shining on
the surface of waters.-ii'
114
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81/
Organic waste is also contributed by water storage of logs.—
In the northwest United States, logging operations at higher elevation
are most active between May and December due to weather conditions.
However, pulp, plywood, and sawwood mills must operate year-round.
Thus, logs must be stored before they are processed. Storage on dry
land often induces losses by insects, diseases, and by excessive crack-
ing due to rapid drying. To prevent these losses, logs are usually
stored in private ponds, public bodies of water, or sprinkled in dry
land decks. Leachates from logs stored in water increase both the chem-
ical and biochemical oxygen demands (COD and BOD) of the water; taste
and color deteriorates, and bark peeled from improperly stored logs
poses a physical hazard to life in the water body.
4.3.5 Application of chemicals: Over the past quarter
century, many synthetic compounds, including pesticides, fertilizers,
and fire retardants have been used in forestry to realize increased
forest production goals. Many of these chemicals will continue to be
used, some at increased levels. These chemicals have the potential
to pollute the waterways.
(a) Pesticides: In pesticide statistics, pesticide use
in forestry (silviculture) is usually included in the category of indus-
trial pesticide uses. Chemical pesticides are used in forestry for
the control of insects, weeds, plant diseases, rodents, etc.
The U.S. Department of Agriculture^/ reports that
forest insects and diseases are responsible for losses in the U.S.
each year that far exceed the losses from forest fires. Current annual
forest mortality due to insects and diseases combined is estimated at
about 67 million m3 (2.4 billion ft3). It is estimated that insects
and diseases cause an additional, equal volume of growth loss. Forest
losses would be about 28 million m3 (1.0 billion ft3) higher if no
pest control activities were carried out. The use of chemical insec-
ticides and fungicides is credited with about two-thirds of this saving.
It is anticipated that the increasing demand for timber will necessitate
use of more pesticides in forestry in the future.
(i) Insecticide use: The USDA's Forest Service^-'
has reported major pest control operations by federal, state and private
interests. Data are summarized in Table 4-4.
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TABLE 4-4
89/
PEST CONTROL ACCOMPLISHMENTS IN THE UNITED STATES, 1969^
Hectares (acres)
Trees Treated Sprayed
Southern pine beetle: 439,588
South and Southeast
Black turpentine beetle: 18,277
South and Southeast
Mountain pine beetle: 364,222
Idaho, Utah, Montana,
Colorado, South Dakota, Wyoming
Bark beetle: 64,876
California, Oregon, Washington
White pine weevil: 308,400
New York
Balsam wooley aphid: 43,000
North Carolina
European pine shoot moth: 11,735
Washington, Oregon
Saratoga spittlebug:
Wisconsin
Leafrollers and fall cankerworm:
New Jersey
Spruce budworm:
Idaho, Montana, Minnesota
Miscellaneous: 1,269
Entire United States
Total 1,251,367
54
(135)
4,000 (9,836)
9,630 (23,868)
13,684 (33,839)
116
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The U.S. Department of Agriculture—' reports that
in 1970, about 140,000 kg (310,000 Ib) of insecticides and fumigants
were used by the Forest Service for insect control. Pesticides used
included ethylenedibromide, 106,500 kg (235,000 Ib); fenitrothion,
23,100 kg (51,000 Ib); carbaryl, 6,340 kg (14,000 Ib) ; and smaller
quantities of malathion, benzene hexachloride (BHC) and lindane. Two
forest pests that accounted for a major part of the use of these chemical
insecticides were the gypsy moth and the spruce budworm.
In the first quarter of 1971, the Forest Service
planned to use insecticides on more than 280,000 hectares (700,000 acres)
of forestland. On these, 152,000 hectares (375,000 acres) were slated
for spraying with carbaryl to control the gypsy moth.
The Forest Service has made no aerial applications
of DDT since 1967. Its use of BHC decreased from 3,980 kg (8,790 Ib)
in 1966 to 26 kg (57 Ib) in 1970. The total use of pesticides in these
programs has been reduced from about 613,000 kg (1,353,000 Ib) in 1965
to about 140,000 kg (310,000 Ib) in 1970.
(ii) Herbicide use: Herbicides are used in silvi-
culture more frequently than insecticides and fungicides, but still
only a very small portion of forestland is treated with herbicides in
any given year.—'
Herbicides are used mostly to control undesirable
plant species and weeds in new plantings. Herbicides have also helped
to prevent forest fires by reducing growth of combustible plant materials
on fire breaks and along forest roads.
The U.S. Forest Service sprayed 108,300 hectares
(268,666 acres) for the control of noxious weeds or undesirable woody
vegetation in 1969. This included about 33,600 hectares (83,000 acres)
treated with 2,4,5-T, alone or in a mixture with 2,4-D.^5-'
The USDA—' estimated that 187,000 hectares (463,000
acres) of forest plantings (presumably including publicly as well as
privately owned lands) were treated with chemical herbicides in 1968,
an increase from an estimated 111,000 hectares (274,000 acres) treated
in 1962.
(iii) Fungicide use: Forest diseases reduce the
utility of trees for recreation, game management, and for timber pro-
duction. They kill trees, discolor foliage, retard growth, cause decay
117
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leading to breakage and windfall, and destroy wood in use. The U.S.
Department of Agriculture—' estimates that annual losses of timber
production due to forest diseases are at 47 million m^ (20 billion
board feet), enough lumber to build 2 million 5-bedroom frame houses.
Fungicides are used to a small extent for the con-
trol of diseases on growing stands of timber. Much larger quantities
of fungicides are used for wood preservation; some of these are applied
directly in conjunction with logging operations. An estimated 17
million m^ (600 million ft^) of wood are treated annually with wood
preservatives in the United States.
The major pesticides used to treat lumber and fenc-
92 /
ing materials for rot prevention are creosote and pentachlorophenol.—
The effect of aerially applied forest pesticides on
water quality depends on the initial distribution of the chemical among
components of the forest environment, and the movement of the chemical
among and its persistence within each component of the environment.
Norris and Moore— have made a review on the subject, which is summar-
ized below:
• Aerially applied pesticides will be distributed
initially among four components of the forest environment: air, vegeta-
tion, forest floor, and surface waters, as shown in Figure 4-1 presented
by Foy and Bingham.—' The amount of chemical entering each portion of
the environment will be determined by properties of the chemical, the
equipment used, the application technique, and environmental factors.
• Sometimes a large portion of aerially applied pesti-
cides may not reach the target area. This problem can be minimized by
using proper application techniques and spraying when weather conditions
are favorable.
• Airborne chemicals can be degraded, taken up by
plants, adsorbed on various surfaces, or moved as fine droplets (drift)
or vapor (volatiles) to other locations where they may settle to the
earth or be washed out with rain.
• The amount of spray material intercepted by vege-
tation depends on the nature and density of the vegetation and physical
characteristics of the spray material. Chemical intercepted by vegeta-
tion may be volatilized to the atmosphere, washed off by rain, or adsorbed
on the leaf surface and brought to the forest floor by falling leaves.
The small amounts of pesticides which are absorbed and translocated to
other parts of the plant may be degraded by plant metabolism, excreted
into the soil from roots, or stored.
118
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CHEMICAL APPLIED
WATER-" Decoy, exudai ion -PLANTS —Decay, exudation —»SOIL
_J t
Absorption ' ' Absorption
Surface runoff, sheet erosion, leaching
Figure 4-1 - The Distribution and Fate of Chemicals in the
Environment (After Foy and Bingham2£/)
119
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• The forest floor is a major receptor of aerially
applied spray materials. Chemicals in the forest floor may be volatilized
and then reenter the atmosphere, be adsorbed on soil colloids and organic
matter, leached through the soil profile, adsorbed by plants, or degraded
by chemical or biological mechanisms.
• The portion of the spray material which is not lost
as drift or intercepted by vegetation on the forest floor will fall di-
rectly on surface waters, and offers the greatest potential for short-term
but high-level contamination of streams by pesticides.
• The movement of spray drift from treatment areas
to surface waters may be an important source of pesticides in the aquatic
environment. The amount of spray drift which occurs is influenced by the
carrier, the size of the droplets, and the height of release. Wind speed,
relative humidity, and temperature are environmental factors which in-
fluence the droplet size, rate of evaporation, speed of vertical descent,
and therefore, the extent of lateral movement.x2/ The relationship be-
tween the lateral and vertical movement of spray droplets of different
mean diameters is illustrated in Figure 4-2 presented by Reimer, et al.—'
• Pesticides are carried from spray deposits to
streams by surface runoff and/or leaching. In both situations pesticides
are carried along in solution or adsorbed on suspended matter.
• Conditions which retard the rate of surface runoff
and favor infiltration will minimize the immediate level of stream contami-
nation. This will also reduce the long-term stream load of pesticide be-
cause a long residence time in the soil provides greater opportunity for
degradation and adsorption.
• The amount of chemical actually entering a stream
due to surface flow will be influenced by: distance from stream course
to closest point of chemical application; infiltration properties of soil
or surface organic matter; rate of surface flow; and adsorptive character-
istics of surface materials.
• Leaching or subsurface flow of pesticides is a
relatively slow process capable of moving only small amounts of chemicals
short distances. Harris^"'^I has determined the relative mobility of
120
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H
W
W
W
H
§
3.05
(10)
6.10
(20)
9.15
(30)
12.20
(40)
15.25
(50)
LATERAL MOVEMENT, METER (FEET)
12.20 24.40
(40) (80)
36.96
(120)
8 km/hour (5 mph) WIND
Figure 4-2 - Lateral Movement of Spray Particles of Various Diameters
Falling at Terminal Velocity in a 8 km/hour (5 mph)
Crosswind. Shaded areas indicate uncertainty due to
varying droplet evaporation (from Reimer, Byrd, and
DavidsonZZ/
121
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pesticides in soil columns leached with water (Figure 4-3). Herbicides
in general are more mobile in soil than insecticides.
• Only small quantities of pesticide will enter the
aquatic environment due to the washing action of rain on vegetation over-
hanging stream courses and leaves falling into the water. Some pesti-
cides are excreted from plant roots, but the quantities are small and
only roots in the stream or hydrosoil would add chemicals to the water.
A number of studies have been conducted for observing
pesticide residues in water from treated forested watersheds. The
studies include, those by Morris,67"70/ Marston, et al.,—/ Tarrant, et al.,—/
Lawrence^9-/ Reese and Becker,—' and Davis, et al.— The data are in-
sufficient to draw general conclusions on how pesticide application to
the forests will affect pesticide residues and aquatic life in the
receiving water bodies. The following important observations were,
however, made from these studies: (1) the most important mechanism of
entry of pesticides to the aquatic environment is direct application or
drift of spray materials to the water surface; (2) surface runoff during
intense precipitation is the second most important carrier of pesticides
entering the aquatic environment.
(b) Fertilizers: Fertilization of forested watersheds
is a relatively new but rapidly growing management practice. Selected
tree species on certain soils respond well to the application of chemical
plant nutrients, especially to nitrogen. Groman—' has reviewed the
current status of forest fertilization. At present, fertilizer use on
forests is centered in the Pacific Northwest Douglas fir region and in
the southern pine region. In addition, the young stands of commercial
redwood in northern California and the western hemlock-sitka spruce
along the coasts of Alaska, Washington, and Oregon are judged to have
a potential for responding economically to applications of fertilizer.
In the Pacific Northwest, forest fertilization with
nitrogen started in 1965, reached a level of 47,600 hectares (118,750
acres) in 1970, and is anticipated to be 101,000 hectares (250,000 acres)
per year from 1975-1980.
Forest fertilization in the South started in 1963 on a
limited basis; in 1971 an estimated 44,400 hectares (110,000 acres)
were fertilized.
Urea has been the most frequently used forest fertilizer
and is preferred to other fertilizer forms because of its high nitrogen
122
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PHENOXY AND PlCLORAM
HERBICIDES
^^M^HHH PHENYLUREA, TRIAZINE,
^^^^^^^^B AND OTHER HERBICIDES
CIPC AND TOLUIOINE HERBICIDES
| THIONAZIN
DIAZINON
| DISULFOTON AND PHORATO
| CHLORINATED HYDROCARBON INSECTICIDES
0.0
LEAST
MOBILE
0.25 0.5 0.75
RELATIVE MOBILITY
1.0
MOST
MOBILE
Figure 4-3 - Relative Mobilities of Pesticides iri Subirrigated
Columns of Soil (From Harris *— )
123
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content (46% by weight) and its pelletized form which reduces fertilizer
loss by drift. Nitrogen application rates range up to 224 kg/hectare
(200 Ib/acre).
Response of Douglas fir to nitrogen fertilization has
averaged about 3070 during a 5 to 7 year period, and trees as old as
300 years have shown a growth acceleration.
In the South, the Southeastern upland pine responds well
to fertilization. Here nitrogen alone is expected to enhance growth by
about 5% a year. A second area of predicted response is the flatwoods
coastal plains, where both nitrogen and phosphorus give increase growth
of pines.
Both nitrogen and phosphorus fertilizers are applied to
forest stands by conventional ground equipment, by helicopter, or by
fixed-wing aircraft.
The entry and fate of fertilizers in streams has been
71/
discussed by Norris and Moore.— They stated that many concepts con-
cerning the initial distribution of pesticides apply also to fertilizers,
but there are some important exceptions. The introduction of large,
specially coated urea granules has enabled most of the dispensed fer-
tilizer to reach the intended target, and practically eliminated drift
problems. Furthermore, because very little granular fertilizer is
intercepted by a dry forest canopy, the forest floor is the major
receptor. The initial distribution of fertilizers is therefore restricted
to the forest floor and to the exposed surface water within the treated
areas.
With an appreciable amount of precipitation, urea may
readily move into the forest floor and soil because it is highly water
soluble. Under normal conditions, urea is rapidly hydrolyzed to the
ammonium ion by the enzyme urease. Nitrogen in this form is rapidly fixed
to the soil particles (ion exchange mechanism) where it is relatively
available to the tree roots. When moisture is limited, however, urea
granules may be slowly hydrolyzed on the forest floor, resulting in a
loss of ammonia nitrogen by volatilization.
Fertilizer nitrogen may enter streams by one of several
routes. The greatest potential source is direct application to exposed
surface water. Overland flow, or surface runoff, when it occurs, is an
important carrier of fertilizer nitrogen to the surface waters. Sub-
surface drainage is also a possible route of entry of soluble forms of
nitrogen into streams.
124
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Limited studies have been conducted to date to sample and
analyze stream flow from fertilized watersheds or portions of drainage
areas. Reports of such studies include those by Aubertin,^/ Burroughs
and Froehlich,15/ Klock,^./ Malueg, et al.,lZ./ McCall,^/ Moore,£2/
Thut,86/ Terry and Thut.^5.' In all investigations, application was made
by helicopter. Nitrogen fertilizers, particularly urea, were tested in
all studies except for the study by Terry and Thut^5/ in which phosphate
fertilizer was applied. Groman34/ made the following summary of major
findings on the effect of nitrogen fertilizer on water quality.
• Urea-N and Kjeldahl-N reached short-lived peak concen-
trations shortly after fertilizer application, and returned to pretreat-
ment levels within several weeks. Strong evidence is presented that the
initial increase of urea-N concentrations was primarily due to direct ap-
plication to surface waters; this contention is substantiated by low
initial concentrations where surface waters were intentionally avoided
during application.
• A small increase in ammonia-N above pretreatment levels
was observed shortly after application. Concentrations quickly returned
to pretreatment levels; the magnitude and duration of ammonia-N loss ap-
peared to be associated with surface water application and with volatil-
ization and nitrification losses dependent upon climatic conditions
immediately after application.
• Loss in the form of nitrite-N was minimal and insig-
nificant, apparently due to rapid conversion of nitrite-N to nitrate-N
through nitrification.
• Nitrate-N contributed to the greatest and most persistent
loss of nitrogen on all study areas. The initial significant loss oc-
curred within a period of several days after application, subsequent sub-
stantial losses were associated with precipitation. Virtually all of the
nitrogen losses after the initial peaks associated with application were
in the form of nitrate-N.
• Short-lived and inconsequential ammonium-N losses im-
mediately preceded the nitrate-N losses, and coincided with the initial
onset of precipitation.
• Data from one study suggest the possibility of signifi-
cant interactions involving urea fertilization and discharge of cations
from the watershed. A definite increase in the concentrations of calcium,
magnesium, sodium, and potassium in the stream following fertilization was
observed.
125
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• Losses of applied nitrogen to stream channels ranged
from inconsequential to a maximum of 3%. Data vary according to stream
surface area, rate and consistency of application, and other factors
unique to each study, but approximately one-third to one-half of the
total nitrogen loss may be associated with direct application to the
surface water and immediate riparian zone.
The effect of aerial phosphate fertilization on water
quality has been studied by Terry and Thut—' . A 4-year old loblolly
pine plantation was fertilized by helicopter with 336 kg/hectare (300
Ib/acre) of 45% triple superphosphate. The site was a wet mineral soil
low in phosphorus, the trees were planted on raised beds, and the entire
area was drained by open ditches. Fertilizer was never applied closer
to any drainage ditch than 7 m (25 ft).
The phosphate phosphorus (P04-P) was monitored in drainage
waters. The background level of PO^-P before fertilization was 13 ppb.
A 0.51 cm (0.2 in.) rain caused the level to reach 19 ppb, and a 3.56
cm (1.4 in.) rain was responsible for a level of 176 ppb on the third
day after fertilization. On the seventh day, and thereafter, the levels
ranged between 9 and 24 ppb, with a median of 16 and a mena of 17 ppb.
(c) Fire retardants: Fire retardants used in silviculture
include water, water plus a wetting agent, borates, bentonite clays,
and currently Firetrol® (ammonium sulfate) and Phoschek® (diammcnium
phosphate). Borates and bentonites are no longer used extensively.
Dodge— has characterized the two most common fire retardants, Firetrol®
and Phoschek® as follows:
• Firetrol® contains ammonium sulfate (fire retardant),as a
attapulgite clay (magnesium silicate) as a thickening agent, sodium
dichromate as an inhibitor of corrosion, and ferric oxide as a coloring
agent so it can be readily seen.
• Phoschek consists of diammonium phosphate as a fire
retardant, sodium carboxymethylcellulose as a thickening agent, "Dowicide A"
(sodium orthophenylphenate) as a bactericide, and sodium fluorosilicate as
a corrosion inhibitor.
126
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Normal use of fire retardants consists of dropping them
from an aircraft ahead of the fire, in an inverted V pattern, at or
beyond the crest of a ridge.
The literature does not contain documentation of adverse
effects of fire retardants on surface water quality. However, it is
apparent that entry mechanisms of fire retardants to streams would be
similar to those of fertilizers. The use of fire retardants has the
potential of increasing ammonia and nitrate concentrations in streams
and lakes. However, the hazard to the water environment is minimized
if accidental or improper applications of chemicals to streams or lakes
are avoided.
4.3.6 Nutrient cycling: There is much current interest in
the loss of nutrient chemicals from forests and the effect of these
chemicals on surface water quality. As has been previously discussed,
an increase in the nutrient level of a stream may result from the use
of fertilizers and fire retardants in forests. Research studies indicate
that logging and forest fires may increase nutrient inputs to streams.
An understanding of nutrient cycling processes on forestland is needed
to explain how this happens.
The nutrient budget in forest ecosystems, similar to an energy
budget or a water budget, consists of input, output, and intrasystem
movement of nutrients. Brown^./ and Fredriksenr^.' recently summarized
information concerning nutrient cycles in forest ecosystems, and the
effect of forest disturbances on nutrient release.
(a) Nutrient inputs: Sources of nutrient input to the
forest ecosystem include soil, rock, and atmosphere. Release of minerals
from soil and rock is due to biogeochemical weathering, which is a slow,
but continuous process. Weathering rates vary widely among different
climatic, topographic, and geologic situations. At higher elevations
or northern latitudes, where the climate is cold and dry, biogeochemical
weathering rates are extremely slow, as exemplified by shallow and poorly
developed soils. The wetter, milder climate usually results in notice-
ably higher rates of weathering.
From the atmosphere, the nutrients reach the forest eco-
system through one or two pathways, precipitation or fixation. Precipi-
tation is an important source of nutrients for forest ecosystems.
Nutrient concentrations in precipitation are relatively constant at any
one site, but may vary widely geographically. Levels of air pollution
may greatly affect nutrient concentrations in precipitation.
127
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In some ecosystems, nutrients, particularly nitrogen,
are fixed directly from the atmosphere by soil organisms. Newton, etal.,—
has estimated that nitrifying bacteria may accumulate up to about 290 kg
of elemental nitrogen per hectare per year in alder stands in western
Oregon .
(b) Intrasystem cycling: A portion of the nutrient
input into the forest system is retained or stored. Some nutrients are
taken up from the soil by vegetation and may be temporarily stored in
the standing biomass. As a forest grows and matures, an increasing
proportion of the nutrient capital is tied up in nondeciduous biomass.
The nutrients in the nondeciduous parts remain fixed until the plant
dies or plant parts fall to the forest floor. Decomposition of this
material releases the nutrients, some of which return to the forest
soil. Some are taken up anew by vegetation.
(c) Nutrient output: Nutrient losses from the forest
system may occur: (1) as dissolved and suspended constituents in streams;
(2) by removal of material from the land; and (3) by volatilization to
the atmosphere. From the undisturbed forests, nutrient losses are
usually very low, in the absence of natural catastrophes. Nutrient
export during natural catastrophic flood and erosion events has not
been documented. On a longer, geologic time scale, such events may
assume greater importance to a forest ecosystem.
Combination of nutrient inputs, intrasystem cycling, and
nutrient outputs provides a generalized diagrammatic model for nutrient
flow in a forest ecosystem as illustrated in Figure 4-4.
(d) Effect of forest disturbances on nutrient release:
From undisturbed forests, stream water contains nutrient constituents
not taken up by vegetation or stored in other parts of the forest eco-
system. Nutrients may be released by weathering, lost by leakage from
intrasystem cycling, or carried to surface waters by precipitation. In
this case nutrient levels are usually low.
When the forest system is disturbed, such as by logging
and burning, the intrasystem cycling of nutrients will be disrupted.
Trees no longer take up nutrients, and the nonmerchantable parts of
trees increase forest litter. Increased temperature and water content
of the soil accelerate the activity of microorganisms that break down
forest litter. The increased activity of the microorganism system raises
the bicarbonate anion level and leaches cations from the system.
128
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Atmosphere
Fixation
Precipitation
Volatilization
\Throughfall
and
Litterfall
\
Uptake Decomposition
A "
Export in
Stream Flow
Figure 4-4 - A Nutrient Cycle for a Forest
(after Brown£')
129
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Vegetation destruction in forested watershed has often
been shown to result in increases of various nutrient concentrations in
CO/
surface waters. Likens, et a !.,_£/ reported a study conducted at the
Hubbard Brook Experimental Forest in New Hampshire, on the effect of
large scale forest cutting on nutrient release. This watershed was
mixed northern hardwood forest on podzolic soils derived from glacial
till. After a period of calibration, a small forested watershed was
devegetated while a second calibrated watershed remained untreated.
Trees were felled but not removed from the devegetated watershed and
vegetation regrowth was inhibited for 2 years by herbicide application.
Changes in streamflow and water quality were monitored. Annual stream-
flow increased by 337» the first year and by 28% the second. Nitrate
concentrations were 41 times higher than in the undisturbed watershed
the first year after cutting and 56 times higher the second year,
ranging from 40 mg/liter to as high as 90 mg/liter.
i i
Other cations increased as follows: Ca by 4.2 times,
Mg"1"1" by 4.1 times, K by 15.6 times, and Na by 18 times.
In addition to the study conducted at Hubbard Brook,
three other studies have focused on the impact of forestry on nutrient
release. These studies include those at Cascade Range, Oregon;2_8/
Alsea Watershed, Oregon;—' and Cedar River watershedil/ in Washington.
In the Cedar River study, where nutrient movement through a forest soil
influenced by tree removal and the addition of fertilizers was studied,
it was concluded that: "the forest soil considered in this study is not
subject to leaching losses in spite of its high porosity and low exchange
capacity. Only small amounts of nitrogen, phosphorus, potassium and
calcium were removed beyond the effective rooting depth during the 10-
month period (after treatment) . . . removing the forest vegetation in-
creases the forest floor decomposition as assessed by the elemental
release. However, little of this additional release was lost from the
soil profile."
From these studies, it is apparent that the degree of
nutrient release after disturbances such as cutting or burning varies
widely as functions of characteristics of soils, vegetation, and climate,
and other factors which describe a watershed.
Commenting on how these factors affect nutrient release,
Brown— explained that:
130
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"Soil characteristics, such as porosity and texture,
determine the pathway and rate of water movement in or
over soil, soil erodibility, and how strongly nutrients
will be held within the soil matrix. Vegetation charac-
teristics, such as species composition, influence the
rate of nutrient uptake. The revegetation rate influ-
ences the rapidity with which recycling begins after
system disruption. The form, chemistry, amount, and
intensity of precipitation influence the leaching rate."
83 /
4.3.7 Bacteria:— A certain level of bacteria concentration
is always present in streams in forested watersheds. Even maximum
possible isolation of forested watersheds cannot entirely safeguard
the purity of water. Petersen and Boring—' reported on densities of
coliform and Escherichia coli serotypes present in two semi-isolated
streams in Colorado. Coliform densities were found to be quite uniform
over much of the sampling period, but the presence of cattle in the
stream and drainage from flood irrigation both steeply increased coli-
form density.
Tree debris, livestock and wildlife in forested watersheds
are sources of organisms in stream water. Pathogens can be attributed
to forest workers and recreationists. Discharge of fecal waste, garbage,
wastewater, or other polluting materials from conveyances passing through
or over watersheds is also a source of bacterial pollution.
There is some evidence that the forest floor can act as a
bacterial filter. NikolaenkoHH.' found that snowmelt that had passed
through a strip of forest on the bank of a reservoir contained fewer
bacteria than water that had not passed through the forested strip.
Kunkle and Meiman-^1' measured bacterial groups in water from
mountain watersheds in Colorado. Total coliform, fecal Streptococcus,
and fecal coliform bacterial groups were closely related to the physical
parameters of the stream and were especially dependent on the "flushing
effect" of runoff from snowmelt and rain, summer storms, or irrigation.
The seasonal trend for all bacterial groups was similar: (1) low
counts prevailed while the water was at 0°C, although bacteria from all
groups were identified during winter; (2) high counts appeared during
rising and peak flows caused by June snowmelt and rain; (3) a short
"postflush" decrease in bacterial counts took place as the runoff
receded in early July; (4) higher bacterial counts were again found in
the July-August period of warmer temperatures and low flows; and (5)
counts declined in September.
131
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The causes of variation in bacterial numbers in a small, un-
fr\ I
polluted stream were studied by Morrison and Fair.— These authors
concluded that the most important cause was summer rainstorms of short
duration, which cause overland flow. When streamflow is stable during
periods of no precipitation, bacterial numbers can be related to the
size of the water-streambed contact surface. As streamflow increases
after precipitation, bacteria can be deposited in the groundwater asso-
ciated with the stream, and later released into the stream as it recedes.
Bacterial numbers fluctuate during the winter even when temperatures are
as low as 0°C to 5.5°C. When cattle and wildlife are concentrated in
areas adjacent to the stream, the bacterial density of the stream also
rises.
4.4 Prediction of Pollution from Silvicultural Activities
4.4.1 Overview: The present state-of-the-art on prediction
of pollution from forestlands is very crude. There are no universally
applicable methods which can be used to predict the quality and quantity
of pollution from a forested watershed. However, this study identifies
some methods which have been used on certain forest areas. These methods
will be presented in the following paragraphs. Depending on the local
situations, the water quality planner/engineer may directly use them
as predictive tools, or he may use them as references for developing
necessary tools for quantifying nonpoint source pollution in his area.
One type of method is concerned with prediction of soil erosion
and sediment production. This type of method is discussed at length in
Section 4.4.2. Rates of soil erosion directly affect suspended sediment
levels in surface waters. A methodology which is called PASS (First
Approximation of Suspended Sediment) has been proposed to approximate
suspended sediment levels based on erosion prediction methods and
hydrologic characteristics of watersheds. PASS is presented in Section
4.4.3. Section 4.4.4 presents a method which deals with prediction of
thermal effect resulting from devegetation of forested watersheds.
Prediction methods are not available for other pollutants, such as
pesticides, fertilizers, fire retardants, organic waste, nutrients, and
bacteria.
4.4.2 Prediction of Soil Erosion and Sediment Production:
Sediment from forest areas may be attributed to four different produc-
tion processes: surface erosion, gully erosion, mass soil movement,
and channel erosion. Prediction methods pertinent to these processes
are discussed below.
132
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(a) Surface erosion: The following components signi-
ficantly affect the water erosion of soil surfaces: (1) soil character-
istics; (2) topographic characteristics; (3) land cover conditions;
(4) regional rainfall characteristics; and (5) erosion control practices.
The relative susceptibility of the soil to the erosion process is termed
erodibility. In general, the finer textured soils—high in silts and
clays--are more erodible than the coarser textured sandy soils. The
topographic characteristics which affect soil erosion are the slope of
the soil and the length of slope. Generally, soils with steeper and
longer slopes are more susceptible to erosion than lesser and shorter
slopes. The land cover factor refers to the ability of a cover, such
as crops, grass, and trees, to absorb the impact energy of rainfall.
The rainfall characteristics consider the amount of rainfall and kinetic
energy of raindrops, which directly effect the detachment of soil and
initiate erosion. Erosion control practices are those which reduce the
erosion potential of the runoff by their influence on drainage patterns,
runoff concentration, and runoff velocity.
The essential factors discussed above have been considered
entirely or partially in the Universal Soil Loss Equation, and the Musgrave
Equation, proposed by Wischmeier and Smith,—and Musgrave,—', respec-
tively. These equations were originally developed to predict erosion from
croplands, but later were adapted to certain forestry areas. The reader
is referred to Section 3.0, of this report and references 1, 64, 95-98,
for the use and limitation of the Universal Equation and the Musgrave
Equation. While methods used for the evaluation of soil, topographic,
and rainfall characteristic factors included in the soil loss equations
are commonly used in soil loss predictions, and have been discussed
in Section 3.0 of this report, evaluation of Cover and Control Practice
Factors pertinent to forestry situations deserves special mention.
The Cover Factor used in the soil loss equations refers
to the ability of a cover, such as vegetation, to reduce erosion loss.
In forests, a layer of compacted decaying duff or litter several inches
thick is very effective against water erosion. Research results indicate
a value of Cover Factor as low as 0.001 for woodland with a 1007» cover
of such duff.-2£/
For forests, Wischmeier— has developed a procedure for
approximating Cover Factor based upon three separate and distinct but
interrelated zones of influence: (a) the vegetative cover in direct
contact with the soil surface; (b) canopy cover; and (c) effects at and
beneath the surface. Typical values for Cover Factor for woodland are
included in Table 4-5.
133
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TABLE 4-5
COVER FACTORS FOR WOODLAND^/
Stand
Condition
Well stocked
Tree Canopy^/ Forest Litter—'
% of Area % of Area
Medium stocked
100-75
75-40
Poorly stocked 40-20
100-90
90-75
70-40
c/
Undergrowth—7
,
Managed—
Unmanaged—
Managed
Unmanaged
Managed
Unmanaged
Cover
Factor
0.001
0.003-0.011
0.002-0.004
0.01 -0.04
0.003-0.009^
0.02 -0.09
e/
a/ When tree canopy is less than 20% the area will be considered as
grassland or cropland for estimating soil loss.
b_/ Forest litter is assumed to be at least 5 cm (2 in.) deep over the
percent ground surface area covered.
£/ Undergrowth is defined as shrubs, weeds, grasses, vines, etc., on
the surface area not protected by forest litter. Usually found
under canopy openings.
d_/ Managed—grazing and fires are controlled; unmanaged--stands that
are overgrazed or subjected to repeated burning.
e_/ For unmanaged woodland with litter cover or less than 75%,Cover
Factor values should be derived by taking 0.7 of the appropriate
values in Table 1 of Ref. 96. The factor of 0.7 adjusts for the
much higher soil organic matter on permanent woodland.
134
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It should be pointed out that tree canopy, forest litter
thickness, and undergrowth conditions are only part of the parameters
to be recognized. In most cases, grass cover and stone content as well
as type of overstory also need to be assessed.
The Erosion Control Practice Factor for croplands denotes
some soil conservation method other than vegetation management, such as
strip cropping, contouring, or terracing. For forests, control practice
can be exemplified by the use of buffer strips, and/or other practices
which affect patterns of drainage from roads, skid trails, clearcut areas,
etc. Values of control factor associated with various practices in
forestry are yet to be defined.
(b) Mass soil movement and channel erosion: In a USDA
study on the sediment yield from the Eel and Mad River basins,—' the
sediment contribution from mass soil movement and channel erosion was
estimated by using aerial photographs. On recent aerial photographs,
the location of landslides or streambank erosion sites were identified.
On the photographs measurements were made of the cross-sectional area
and depth of voided area of landslides, and channel area and channel
depth of channel erosion sites. The measurements were repeated on older
aerial photographs covering the same area. The amount of material eroded
in the time span is represented by the difference in volume measured
on both sets of photographs. Dividing this volume by the number of
years between the photo-takings gives the estimated annual volume of
sediment produced by landslide or streambank erosion.
(c) Gully erosion: Sediment production from gullies can
be estimated by using the same methodology as that for landslide and
channel erosion. Dissmeyer-^-' suggested Equation (4-1) for such
estimation:
G = F V / , (4-D
where G = gully erosion,
F = conversion factor,
Lg = gully length,
X = average gully cross-section eroded in years of estimate, and
Y = years of estimate.
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4.4.3 Prediction of suspended sediment concentrations:
Water quality planners are more concerned with the quantitative effect
of various silvicultural activities on suspended sediment concentrations
in surface water than the rate of soil erosion or sediment production.
Concerning suspended sediments in water from forest lands, water quality
planners may ask, for example, What is the suspended sediment contri-
bution of each land use or disturbance within the forest? What silvi-
cultural activities or land uses are yielding excessive sediment, and
why? What control or preventive measures are required to reduce the
suspended sediment to acceptable levels? How can the effect on suspended
sediment due to various remedial measures be predicted?
(a) Prediction procedures: In this section, a procedure
which has been proposed to predict the suspended sediment is presented.
It is called First Approximation of Suspended Sediment (FASS), proposed
by Dissmeyer.1°?20/ Basically, the procedure distributes sediment
yield among land uses and/or disturbances above the point of measurement.
The FASS procedure includes the following major steps:
(1) Stratifying the study area using soils, slope,
vegetation, land uses, land disturbances, and quality and type of
management;
(2) Field sampling strata for erosion and sediment
production;
(3) Computing erosion and estimated sediment produc-
tion volumes for each land use or disturbance;
(4) Computing gross erosion and estimated sediment
production of the watershed;
(5) Computing storm flow, base flow, and annual
flow for watershed; and
(6) Computing average suspended sediment concentra-
tions for storm flow, base flow, and annual flow.
Estimating erosion and sediment production rate for each
land use or disturbance (Steps 1-3): The watershed is stratified based
on factors which greatly affect soil erosion and sediment yield. These
factors include soil type, ground slope, slope length, soil cover, land
use, disturbance, and quality and type of management. Data for each
stratum are obtained through literature and field surveys.
136
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A field survey method has been proposed by Dissmeyer to
estimate production ratio, which is the percentage of soil loss from a
stratum that is moved to a stream. The method is based upon tracing
the soil movement downhill and subtracting erosion that is trapped by
obstructions such as litter, limbs, logs, depressions, and benches.
Since the sediment delivery ratio is greatly influenced by soil texture,
such estimates can be made by using the textural triangle, shown in
Figure 4-5. The textural triangle can be used to approximate the per-
centages of sand and fines (combination of clays and silts) from the
type of soil texture, such as loam, silty loam, or whatever. From this
information, plus results of observation on the erosion sites and
along transport routes, the observer can estimate the percentage of soil
erosion that reaches the nearest stream. For example, a medium clay loam
has approximately 35% sands and 65% fines. The site inspection of a
plot with this kind of soil results in an estimate that 20% of sands
and 70% of fines reach the stream. If the plot is eroding at 22.4 metric
tons/hectare/year (10 tons/acre/year) the plot is yielding 1.6 metric
tons/hectare (0.7 tons/acre) of sands and 10.2 metric tons/hectare (4.55
tons/acre) of fines per year.
Computing gross erosion and sediment production (Step 4):
The amount of soil erosion and sediment production from each stratum is
calculated by multiplying the erosion rate and sediment production rate
by the stratum area. The sum of these by disturbances (roads, yarding
areas, etc.) gives the total erosion and sediment production from forest-
land.
In river basin planning, sediment production from channel
erosion, landslides, and gully erosion, should also be taken into account.
Furthermore, contributions from the nonforested areas, such as agri-
cultural lands, highways, and urban areas should be included. The
amount of erosion from all these processes from forested and nonforested
areas are summarized to produce the gross erosion of the watershed.
Computing storm flow, base flow and annual flows (Step 5):
Research has demonstrated that generally a large portion of sediments is
carried by direct runoff during storms, or the so-called storm flow.
The remaining portion is carried by base flow. Dissmeyer has suggested
that average suspended sediment concentrations be estimated for a year,
and for both storm flow periods and base flow periods.
For a watershed, storm flow volumes are computed using
USGS Water Supply Papers and the following equation:—
137
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SILTY
CLAY
SANDY
CLAY
\ \/ \ / \ f \ SILTY
CLAY LOAM \ CLAy LQAM \ ^
SANDY
CLAY LOAM
/ V
SILTY LOAM
SANDY LOAM
V
-PERCENT SAND
Figure 4-5 - Textural Triangle of Soils (after Dissmeye:
20/
138
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(4-2)
where N = time for terminating direct runoff, days, and
A = drainage area, km2.
This equation was established based on the observation that, for a
given watershed, the time of direct runoff is relatively constant from
storm to storm.
The storm flow volume is the total volume from the time
of the first significant rise to N days after the peak. The annual
storm flow volume is the sum of storm flows in a year. Base flow is
the difference between total annual runoff and storm runoff.
Computing average suspended sediment concentrations for
storm flow, base flow and annual flow (Step 6): If a stream has a water
quality monitoring station which measures suspended sediment, and the
average annual suspended sediment concentration is available, the aver-
age sediment concentrations during storm flow periods can be approximated
by
P WQ
s m
WQS = , (4-3)
where WQ = average suspended sediment concentration
S
(mg/liter or ppm) in storm flow,
P = proportion of sediment carried during storm
flow period,
WQ = average annual suspended sediment concentration
(mg/liter or ppm), and
Q = proportion of annual runoff contributed by storm flow.
S
The proportion of sediment carried during storm flow periods varies,
but research results generally indicate a range of 0.80 to 1.00. A
good approximation would be 0.90 >' if no better data are available.
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The remaining sediment would be yielded during the base
flow periods. Therefore, the average suspended sediment concentration
during base flow can be approximated by
(l-Ps)WQm
WQK = - , (4-4)
U-QB>
where WQ = average suspended sediment concentration
(rag/liter or ppm) in base flow.
When measured suspended sediment data are not available,
Eq. 4-5 can be used to approximate average sediment concentration for
annual flow:
Pbws
WQm = - , (4-5)
where W = annual gross sediment yield,
s
Q0 = annual flow volume, and
ci
P^ = proportion of sediment production which
reaches the point of measurement.
The factor P, is included in Eq. 4-5 to take into account the effect
of sediment sinks during stream transport. Values of this factor
should be evaluated based on stream conditions and characteristics of
soil sediment, etc. (Note: Eq. 4-5 is added, in this presentation of
PASS, by the authors of this report.)
FASS can also be used to identify problem areas, to
prescribe control measures to reduce suspended sediments, and to evaluate
the effectiveness of remedial actions. To accomplish this, the procedure
described above is expanded to include the following steps.
Step 7 - Distributing sediment yield among land uses and
disturbances in proportion to their individual contribution to the gross
sediment production.
Step 8 - Identifying land uses and disturbances that need
suspended sediment contribution reduced, and prescribing corrective measures.
Step 9 - Projecting benefits of recommended sediment control
programs.
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Distributing sediment yield among land uses and distur-
bances (Step 7): The sediment concentrations for either annual, base,
or storm flow periods are distributed among land uses and disturbances
in proportion to their individual contribution to the gross sediment
production. For example, if skid trails produce 77o of the estimated
sediment production and the average storm flow concentration is 70 ppm,
then the contribution by skid trails is 4.9 ppm.
Identify land uses and disturbances that need suspended
sediment contributions reduced and prescribe corrective measures (Step 8):
The previous step identifies the relative contribution of each land use
or disturbance to the total suspended sediment concentration. For
example:
Skid trails 4.9 ppm
Spur roads 1.3
Mechanical site preparation 56.1
Logging 0.4
Fire 6.9
Log decks 0.4
Total 70.0 ppm
In this example, mechanical site preparation would gain our first
attention, followed by fire, skid trails, and spur roads.
Corrective measures would be prescribed and evaluated by
the Universal or Musgrave Equations and the FASS Procedure. From these
evaluations, the benefits of the recommended sediment control program
would be evaluated and the expected future water quality could be
predicted (Step 9).
FASS using reservoir sedimentation data: When suspended
sediment data are not available, but reservoir sedimentation is available,
FASS contains a procedure for approximating suspended sediment concentra-
tions using soils information and reservoir sediment data. This pro-
cedure has been discussed in detail by Dissmeyer.—
(b) Methods of data collection: The required data for
prediction of soil erosion and sediment production, and approximation
of suspended sediment concentration from a given watershed, are obtained
from a survey of relevant literature (presurvey review), and from on-site
inspection (field survey).
141
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In the following paragraphs, general approaches to conduct-
ing presurvey reviews and field surveys are presented. This material is
synopsized from the U.S. Forest Service Manual, "Hydrologic Surveys and
Analysis," (FSM 3570).
Presurvey review: At the outset of the survey, considerable
basic data are usually available in the form of maps, aerial photographs,
geology and soil reports, forest survey and range allotment analysis
reports, stream flow and precipitation records, research publications,
barometer watershed results, etc. These data should be collected and
reviewed prior to a field investigation to gain a general understanding
of the landscape, the resources, and problems connected with the use of
the resources.
A list of data and information sources follows:
1. Topographic maps
a. Quadrangle maps: Department of the Interior, Geological
Survey, Topographic Division; and Department of the Army,
Army Map Service
b. National parks and monuments: Department of the Interior,
National Park Service
c. National forests: Forest Service
d. Local areas: commercial aerial mapping firms
2. Planimetric maps
a. Plots of public land surveys: Department of the Interior,
Bureau of Land Management
b. Forest Service planimetries
c. County maps: county surveyor or county engineer
d. Federal Reclamation Project maps: Department of the Interior,
Bureau of Reclamation
3. Aerial photographs
a. The following federal agencies have aerial photographs of
parts of the United States: Department of the Interior,
142
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Geological Survey, Topographic Division; Department of
Agriculture--Agricultural Stabilization and Conservation
Service, Soil Conservation Service, and Forest Service;
Department of Commerce, National Ocean Survey; Department
of the Air Force; and National Aeronautics and Space Adminis-
tration. Also, various state agencies and commercial aerial
survey and mapping firms have inventories of aerial photographs.
4. Transportation maps
a. State transportation maps: Department of Transportation,
Bureau of Public Roads
b. State and county highway maps: state highway departments
c. Sectional aeronautical charts: Department of Commerce, National
Ocean Survey
5. Geology
a. Geologic maps and reports: Department of the Interior,
Geological Survey, Geologic Division; state geological surveys
or departments; and logged wells
6. Soils
a. County soil survey reports: Soil Conservation Service
and Forest Service
b. Land-use capability surveys: Soil Conservation Service
c. Land classification reports: Department of the Interior,
Bureau of Reclamation
7. Vegetation
a. Forest survey reports: Forest Service
b. Range survey reports: Forest Service and Soil Conservation
Service
c. Game census reports: federal and state fish and wildlife
services
143
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d. Fire statistics: federal and state foresters' reports
e. Cutting records: federal and state foresters' reports
8. Climatological data
a. Climatological data (monthly and annual summaries): Department
of Commerce, Weather Bureau; and power companies
b. Hydrologic bulletin and technical papers: Department of
Commerce, Weather Bureau
c. Cooperative study reports: Department of Commerce, Weather
Bureau; and Department of the Interior, Bureau of Reclamation
d. Fire-weather reports: Forest Service and state foresters
9. Stream flow data
a. Water-supply papers: Department of the Interior, Geological
Survey, Water Resources Division
b. Reports of state engineers and other divisions of
state governments
10. Sedimentation
a. Water-supply papers: Department of the Interior, Geological
Survey, Quality of Water Branch
b. Reports: Department of the Interior, Bureau of Reclamation;
Department of Agriculture, Soil Conservation Service and
Agricultural Research Service
11. Research results
Technical journals; technical abstract services
12. Basin and project reports and special reports
Department of the Army, Corps of Engineers; Department of the
Interior, Bureau of Land Management, Bureau of Mines, Fish and
Wildlife Service, National Park Service,* and Environmental
Protection Agency; Department of Agriculture, Forest Service and
144
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Soil Conservation Service; state departments of water resources,
public works power authorities, and planning commissions
The great variation in the physical factors that affect
runoff, soil movement and sediment delivery calls for a careful deter-
mination of what is to be sampled. One of the fundamental principles
for increasing precision in sampling is to stratify the population into
a minimum number of relatively homogeneous units. To achieve this, com-
plex watersheds or parts thereof may be subdivided into physically homo-
geneous strata that will give the least variation in runoff and soil loss.
The strata would be areas where the important factors that affect runoff
and soil loss show strong uniformity. These are factors that index
characteristics of soils, geology, physiography, vegetation, and land use.
Field survey: Following stratification of the area on
the basis of a review of available data, a reconnaissance is made of
the watershed in order to observe how the mapped strata appear on the
ground and to correct or supplement them if necessary, and to obtain
estimates of amounts of erosion and detailed characteristics of the
factors that affect erosion and sediment production.
Sampling must be carried out on representative parts of
the stratum. The number of samples required depends on what is decided
as necessary to provide an adequate knowledge of the characteristics
and potentials of the area. The dimensions of certain strata, and know-
ledge of soil, cover, and land-use problems as obtained on the reconnais-
sance investigation, will serve as guides to the location and amount of
sampling required.
Strata will be sampled by significant sources of runoff
and sediment. In all cases this will involve separate sampling for the
vegetated areas and roads and skid trails. Where other significant
sediment sources prevail, such as channels, gullies, landslides, and
strip-mined areas, separate sampling should be carried out on each source.
Field data to be collected during field surveys for the
areas underlined above are briefly discussed below,
1. Vegetated area: Field plot and transect procedures
are used to obtain the following information from the vegetated
watershed surfaces. The information is used to estimate present rates
of soil loss and runoff; and future rates where they will be changed by
land use, vegetative treatment, and management practices.
145
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• Geology and soils: Soil origin, and soil characteristics
(soil texture, soil depth).
• Sediment delivery ratio: The percentage of soil loss
material from a plot that has been moved or could be moved into a stream,
depending on topography, vegetative cover, .the plot's proximity to a
drainage channel, and the presence or absence of impediments to the move-
ment of materials into the stream.
• Physiography: Slope, slope length, slope position, and
exposure.
• Vegetative cover: General vegetative type, forest type,
stand size, litter depth, humus depth, humus type, crown density, range
types, ground cover density, and vegetative disturbance (fire damage,
animal damage, logging damage, etc.).
• Land-treatment measures: Vegetative land treatment, and
structural or mechanical measures.
• Land status: Land use, ownership, and management status.
2. Roads and skid trails: A sampling of roads and skid
trails should be made to determine amounts of soil loss occurring from
these uses. Areas bared by roads, trails, and landings should be mea-
sured. Depth of erosion on roads is measured along cutbanks as evi-
denced by gullies and rills on the surface, by the extent the slope toes
have moved back from the edge of the road and ditches, and by the length
of roots extending from the banks. An estimate is made of the percentage
of soil loss that is becoming sediment in streams as was done on the
vegetated areas.
3. Channels, gullies, and landslides: Soil loss from
active gullies, landslides, and live streams should be estimated if
these are significant sources of sediment in the area under investigation.
Field sampling includes dimensional measurements of length and cross-
sectional areas of gullies, and landslides, etc.
4.4.4 Prediction of thermal effects: A temperature predic-
tion method was developed by Browoi^' using energy budget techniques to pre-
dict the magnitude of the change in temperature following forest exposure,
such as clearcutting, logging and burning. The model is expressed as
146
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(4-6)
where AT = the predicted temperature change in °C (°F),
A = the surface area of the section of the stream exposed
o n
(by clearcutting, for example) in m*- (ft ) ,
H = the net heat input to the stream in Kcal/m2-min
(Btu/ft2-min),
D = the stream discharge in m^/sec (ft3/sec), and
C, a constant = 1.67 x 10~5 when AT is in °C, A in m2, H in Kcal/m2-
min, and D in m3/sec (C = 2.67 x 10"^ when AT in
°F, A in ft2, H in Btu/ft2-min, and D in ft3/sec).
Except for H, determination of terms at the righthand side of Equa-
tion (4-6) is straightforward. Value of H for the specific area can
be measured,—' or calculated.ii/
Calculation of H can be simplified by considering the
solar radiation as the only heat input, and neglecting the effects of
convection, conduction, and evaporation. Calculation of the net radia-
tion for specific areas is made by subtracting the amount of radiation
reflected from the total amount of incoming radiation. The solar
radiation on a clear day can be estimated based on the solar angle,
which in general depends upon the season, time of day, and latitude.
However, because of the symmetry of the solar path, the hourly value
of the solar angle can be predicted based on the sun's angle at solar
noon alone. The midday solar angle can be measured with a solar
emphemeris .JL5/
Methods have been developed for prediction of hourly changes
in stream temperature at any time of the day. However, for water quality
planning, it is often unnecessary to predict the hourly change if the
maximum change is assessed, because the maximum change would be suffi-
cient to permit one to predict any major change in stream ecology.
To predict the maximum change in stream temperature as water
flows through the exposed forested area, an estimate of the maximum input
of heat must be made. This estimate is made at low-flow periods and by
averaging the net radiation about the noon maximum. For the purpose of
this estimation, average midday net solar radiation absorbed by streams
has been determined based on travel time and solar angle, and is plotted
in Figure 4-6.
147
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6
i
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The procedure to estimate the maximum change in stream tempera-
ture as a result of exposure to solar radiation, according to Brown,—'
may be summarized as follows:
1. Mark the upstream and downstream boundaries of the exposed
forest area.
2. Determine the lowest discharge during the summer and the
dates during which it occurs.
3. Determine the surface area of the stream in the exposed
area during the low- flow period.
4. With dye, determine the travel time of the stream through
the area during the low- flow season.
5. From a solar ephemeris, determine the highest sun angle
at solar noon for the period of low flow.
6. Enter Figure 4-6 with the appropriate travel time. Move up
to the correct curve for the sun angle at solar noon and read the average
radiation in Kcal/m2-min (Btu/ft2-min) .
7. Compute the predicted maximum change in temperature using
Eq. 4-6.
According to Brown, et al.,-' Eq. 4-6 has an accuracy of ± 2°C
(± 3°F). This equation has been used successfully on several small
streams. There are limitations in applying this equation, however. Limi-
tations chiefly stem from exclusion of heat transfer by evaporation, con-
vection, and conduction when computing H. BrownS' suggested that this equa-
tion should be applied to relatively short stretches of stream, less than
610 m (2,000 ft), and that H in the equation should be reduced by 15% to
207o on streams with solid rock beds, because of conduction.
4.4.5 Predictive methods for other pollutants: After a thorough
evaluation of literature and data, this study has concluded that methods
are still not available for predicting effects of silvicultural activities
on water quality in terms of parameters such as organics, pesticides,
nutrients, and bacteria. Most of the pertinent data are results of case
studies which depict order of magnitude changes of certain water quality
parameters associated with a specific disturbance or treatment in a given
locale with its unique natural and operational conditions. It is dangerous
to generalize results of such case studies unless research is conducted to
further elucidate the processes responsible for the observed changes.
149
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Until accurate prediction methods are available, we recommend
that a water quality planner/engineer conduct an input-output analysis
to determine what effect the silvicultural activities may have on water
pollution in the local area. Sources of some input data, such as type
and degree of disturbances, climate, topography, etc., have been given
previously. Other information such as application of fertilizers,
pesticides, fire retardants, rafting and water storage of logs, etc.,
may be available from the U.S. Forest Service, Bureau of Land Manage-
ment, state forestry departments, or private forest industries.
The output data—water quality—may be obtained from existing
inventories or by stream monitoring. Methods to obtain this type of
data are discussed in the following section.
4.4.6 Monitoring of water quality: There are numerous sources
of water quality data which can be used by the planner/engineer to de-
termine the effect of pollution on water quality. Among these are the
Environmental Protection Agency, the U.S. Forest Service, the U.S.
Geological Survey, the Army Corps of Engineers, and state water pollution
control agencies.
Most of these agencies have inventories of. data collected by
themselves. The EPA's STORET System, however, has data of most of the
other agencies. It is a very comprehensive source of water quality data
and is highly recommended for planners/engineers. It is in computer-
processible form, and data are retrievable at Regional EPA Offices.
When necessary data are not available from existing stations,
local water quality monitoring programs must be established to determine
the effect of pollution from forestland on water quality. This effect
is normally determined by comparing upstream samples to downstream
samples. This direct comparison normally will provide useful results
in a relatively short period of time. Long term monitoring is essential
to provide natural background water quality levels for proper interpreta-
tion of upstream and downstream data.
Monitoring should normally be limited to those parameters most
likely to be significantly affected by the silvicultural activities.
These parameters include water temperature, turbidity, suspended sedi-
ment, dissolved oxygen, specific conductance, nutrients, and pesticides.
Stream flow should also be measured to assist in interpreting water
quality data.
150
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The sampling frequency must be carefully established so that
all the ranges of water quality that might be experienced from the silvi-
cultural activity are observed. Monitoring schemes must be process-based.
That is, they must be built upon some knowledge of how and when the
pollutant is likely to be produced. For example, we know that forest
chemicals most frequently enter streams during periods of application.
With sediment, we know it enters streams primarily during storm events.
For water temperature monitoring, the sampling should be geared to the
mid-summer, midday period during hot, clear days.
151
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59. McCall, M., "The Effects of Aerial Forest Fertilization on Water
Quality for Two Streams in the Capitol Forest," Washington State
Department of Ecology, Olympia, Washington, 20 pages (1970).
60. Meehan, W. R., W. A. Farr, D. M. Bishop, and J. H. Patric, "Some
Effects of Clearcutting on Salmon Habitat of Two Southeast Alaska
Streams," USDA Forest Service, Pacific Northwest Forest and Range
Experimental Station, Research Paper PNW-82, 45 pages 1969.
61. Megaham, Walter F., and Walter J. Kidd, "Effect of Logging Roads
on Sediment Production Rates in the Idaho Batholith," USDA Forest
Service, Research Paper INT-123, 14 pages, May 1972.
62. Moore, D. G., "Behavior and Rate of Fertilizer Nitrogen Applied to
Forested Watersheds," U.S. Forest Service Contribution Project
Report, Western Regional Research Project, Progress Report,
Forestry Sciences Laboratory, Corvallis, Oregon, 5 pages (1971).
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63. Morrison, S. M., and J. F. Fair, "Influence of Environment on
Stream Microbial Dynamics," Colorado State University, Hydrological
Paper No. 13, 21 pages (1966).
64. Musgrave, A. W., "The Quantitative Evaluation of Factors in Water
Erosion--A First Approximation," J. of Soil and Water Conservation,
2, 133-138 (1947).
65. Newton, M., B. A. Elhassan, and J. Zavitouski, "Role of Red Alder
in Western Oregon Forest Succession," in Biology of Alder, N.W.
Scientific Association Symposium, Pullman, Washington, April
1967; also J. M. Trappe, J. F. Franklin, Agricultural Forest
Service, Pacific Northwest Forest and Range Experimental Station
(1968).
66. Nikolaenko, V. T., "The Effect of Forest on the Drinking Quality of
Water," Lesn. Hoz., 15(12) (1962).
67. Norris, L. A., "Chemical Brush Control: Assessing the Hazard,"
Journal of Forestry, 715-720 (October 1971).
68. Norris, L. A., "Chemical Brush Control and Herbicide Residues in
the Forest Environment," in Herbicides and Vegetation Management,
Oregon State University Press, Corvallis, pp. 103-123 (1967).
69. Norris, L. A., "Herbicide Runoff from Forest Lands Sprayed in Summer,"
Res. Progr. Rep., West. Soc. Weed Sci., 24-26 (1969).
70. Norris, L. A., "Stream Contamination by Herbicides after Fall Rains
on Forest Land," Res. Progr. Rep., West. Soc. Weed Sci., 33-34
(1968).
71. Norris, L. A., and D. G. Moore, "The Entry and Fate of Forest Chemi-
cals in Streams," in Proceedings of A Symposium on Forest Land
Uses and Stream Environment, October 19-21, 1970, Oregon State
University, Corvallis, J. T. Krygier and J. D. Hall, Editors (1971).
72. Osborn, B., "How Rainfall and Runoff Erode Soil," Yearbook of
Agriculture, pp. 126-135 (1955).
73. Peterson, N. J., and Boring, III., J. R., "A Study of Coliform
Densities and Escherichia coli Serotypes in Two Mountain Streams,"
American J. Hyg., 71, 134-140 (1960).
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74. Ponce, Stanley Lewis, "The Biochemical Oxygen Demand of Douglas-Fir
Needles and Twigs, Western Hemlock Needles and Red Alder Leaves
in Stream Water," Master Thesis, Oregon State University, Corvallis,
Oregon, 141 pages, June 1973.
75. Ralston, Charles W., and Glyndon E. Hatchell, "Effects of Prescribed
Burning on Physical Properties of Soil," in Proceedings, Pre-
scribed Burning Symposium, USDA Forest Service, pp. 68-85,
April 14-15, 1971.
76. Reese, C. D., and L. Becker, "The Movement and Impact of Pesticides
Used in Forest Management on the Aquatic Environment and Ecosystem,"
Pesticide Study Series 7, U.S. Environmental Protection Agency (1972).
77. Reimer, C. A., B. C. Byrd and J. H. Davidson, "An Improved Helicopter
System for the Aerial Application of Sprays Containing Tordon 101
Mixture Particulated with Norbak," Down to Earth, 22(1) :3-6 (1966).
78. Reinhart, K. G., and A. R. Eschner, "Effect of Stream Flow of Four
Different Forest Practices in Allegheny Mountains," Journal Geophys.
Res., 67, 2433-2445 (1962).
79. Rice, R. M., J. S. Rothacher, and W. F. Megahan, "Erosional Conse-
quences of Timber Harvesting: An Appraisal," Proceedings of a
Symposium on Watersheds in Transition, held at Ft. Collins,
Colorado, 405 pages, pp. 321-329, June 19-22, 1972.
80. Rice, R. M., and J. R. Wallis, "How a Logging Operation Can Affect
Streamflow," Forest Industries, 89, 38-40 (1962).
81. Schaumburg, Frank D., "The Influence of Log Handling on Water Quality,"
Environmental Protection Agency, Corvallis, Oregon, 105 pages,
February 1973.
82. Swanston, D. N., "Principal Mass Movement Processes Influenced by
Logging, Road Building, and Fire," in Proceedings of a Symposium
on Forest Land Uses and Stream Environment, Oregon State Univer-
sity, Corvallis, October 19-21, 1970.
83. Tarrant, R. F., "Man-Caused Fluctuation in Quality of Water from
Forested Watershed," Proceeding of the Joint FAO/U.S.S.R. Inter-
national Symposium on Forest Influences and Watershed Management.
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159
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84. Tarrant, R. F., D. G. Moore and W. B. Bollen, "DDT Residues in
Forest Floor and Soil After Aerial Spraying," Agron. Abstr.,
p. 126 (1969).
85. Terry, T. A., and R. N. Thut, "The Effect of Aerial Phosphate
Fertilization on Water Quality," Weyerhaeuser Company, Little
Rock, Arkansas, 5 pages (1973).
86. Thut, R. N., "Effects of Forest Fertilization on Surface Waters,"
Weyerhaeuser Company, Research Division, Longview, Washington,
Project No. 045-0073, 29 pages (1970).
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20250 (1967).
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with Herbicides and an Evaluation of Important Weeds, 1968,"
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Research Service, ARS-H-1 (1972).
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United States, 1969," Forest Service, Washington, D.C.
(1970).
90. U.S. Department of Agriculture, "Patterns of Pesticide Use and
Reduction in Use as Related to Social and Economic Factors,"
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U.S. Government Printing Office, Washington, D.C. (1972).
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Agricultural Stabilization and Conservation Service, Washington,
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94. Willen, D. W., "Surface Soil Textural and Potential Erodibility
Characteristics of Some Southern Sierra Nevada Forest Sites,"
Soil Sci. Soc. Amer. Proc., 29, 213-218 (1965).
95. Wischmeier, W. H., "A Rainfall Erosion Index for a Universal Soil
Loss Equation," Proceedings of the Soil Society of America, 23(3),
246, 4 pages (1959).
96. Wischmeier, W. H., "Estimating the Cover and Management Factor for
Undisturbed Areas," presented at USDA Sediment Yield Workshop,
Oxford, Mississippi (1972).
97. Wischmeier, W. H., C. B. Johnson, and B. U. Cross, "A Soil Erodi-
bility Nomograph for Farmland and Construction Sites," J. Soil
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culture Handbook No. 282, 47 pages (1965).
161
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5.0 MINING
5.1 Introduction
Mining activities in the United States have affected approxi-
mately 5.3 million hectares (13 million acres) of land, according to
estimates by the U.S. Department of the Interior. This acreage includes
almost 3 million hectares (7 million acres) which have been undercut
by mining activities, and more than 1.2 million hectares (3 million
acres) disturbed by surface mining activities. The remaining acreage
represents land used for containing mining-related mineral waste ac-
cumulations. By the year 2000, the Department of the Interior estimates
that 12 million hectares (30 million acres) will be affected by mining
operations .22.'
While the land area presently affected by mining represents
only about 0.57» of the United States, the effects of mining upon water
quantity and quality are spread over large regions. The effects of
mining include pollution of water supplies with mine drainage and sedi-
ment.
Pollution from mining operations arises because the hydrology
of surface and subsurface waters is altered when the earth's crust is
disturbed to gain access to mineral values held within. The quality
of these waters very often deteriorates, and the quantity is often re-
disturbed as a result of mining operations. Water quality deteriorates
when water supplies are contaminated with soluble products present in
or generated from mining wastes. Water quantity is affected because
natural drainage patterns for surface and subsurface waters are altered.—'
5.2 Nature and Extent of Pollution from Mining Activities
5.2.1 General overview: In the ultimate analysis, any dis-
turbance of the earth's crust will alter the environment in the vicinity
of the disturbance. The degree to which the environment is altered
depends upon the size and depth of the disturbance, the method of the
disturbance, and the nature of the disturbed materials. In the case of
mining, the purpose of disturbing the earth is to extract mineral de-
posits. Methods used are determined by the placement of the minerals
in the earth. Similarly, size and depth of the mine are determined by
the distribution of the mineral at the mining site.
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The extraction of minerals from the earth's crust can be
accomplished by a variety of techniques. For minerals deep in the
earth, mine shafts are sunk to gain access to the deposit. This method
is usually not used if mineral deposits are available for recovery by
surface mining techniques. Underground mining techniques do, however,
tend to retrieve most of the values in the deposit compared to surface
mining techniques.
Surface mining creates more visible defacement of the earth's
surface, and results in disturbance of large land curves. Indiscriminate
surface mining of the past has created problems which are still present
today. However, land disturbed by surface mining can be reclaimed, and
techniques are being developed by which mining and reclamation can be
integrated almost into a single operation. Modified block cutting in
contour surface mining of coal is an example.!£/
The most serious pollutant arising from mining activities is
the mine drainage generated by oxidation of pyritic materials with air
in the presence of water; this drainage is an acidic mixture of iron
salts, other salts and sulfuric acid. Mine drainage arises from both
underground and surface mining sources, and from coal and many metal
mining operations. Coal deposits and so-called hard rock mineral de-
posits are commonly associated with pyrite and marcasite, which are
disulfides of iron. Acid mine drainage can find its way into surface
waters, where the acid and sulfate may result in severe deterioration
in stream quality. The acid can react with clays to yield aluminum
concentrations sufficient for fish kills, and with limestone to yield
very hard waters expensive to soften. The acid can also selectively
extract heavy metals present in trace quantities in mineral and soil
formations, resulting in toxic conditions in lakes and streams.
Mining refuse—waste materials left near the mining site
after raw minerals have been cleaned or concentrated—is another source
of pollution. Much of this refuse contains pyritic material which can
be oxidized to acidic substances. The resultant acid water may remain
in the pile until a rainstorm, at which time it is flushed into nearby
watercourses. Mine drainage "slugs" during storms are very detrimental
to aquatic life in surface waters.
Mining operations also generate wastes, commonly called spoil,
in the form of disturbed rock and soil. If this spoil is left in piles,
erosion and runoff will carry sediment into streams. This sediment is
capable of destroying life in streams, results in decreased capacity of
streams and reservoirs, and destroys fish and wildlife habitats.
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Improperly impounded sediment may be released suddenly as a
mud slide and thus poses a direct threat to life and property.
Mining activities have a pronounced effect on groundwater
supplies. The various operations used to mine the mineral deposits
can result in alteration of groundwater distribution patterns. Aquifers
containing good water can become contaminated because some mining may
disturb bedrock formations, which permit mixing of contaminated water
with good.
In the western United States, raw metal ores of copper, gold,
and silver, etc., are treated so that concentrated ores can be economi-
cally shipped to smelters or other metal refiners. The waste residue
left behind in the concentration process is retained in ponds. Unless
these ponds are carefully sealed, salts will leach into groundwater
which can be recovered at a considerable distance from the source. If
ponds are located on impervious rock, water trickling through the im-
pounded solids will be discharged as polluted leachate in a spring at
the foot of the impoundment.
5.2.2 Acid mine drainage: As stated above, acid mine drain-
age is the most serious source of pollution from mining activities. It
is generally associated with coal mining, although it is not found at
all coal mines. It is also a problem in some hard rock mining areas,
since hard rock mineral deposits are commonly associated with pyritic-
type materials.
Acid mine drainage can arise from both surface mining and from
underground mining. It can also arise from undisturbed coal beds.38.7
In 1698, Gabriel Thomas observed acid drainage associated with coal de-
posits in what is now Appalachia: "And I have reason to believe that
there are good coals, also, for I observed the runs of water which have
the same color as that which proceeds from the coal mines in Wales."
Similarly, the presence of acid drainage was an important indicator
to 19th century prospectors looking for gold in the western United States.
Any opening in the earth which causes pyritic materials to be
exposed to air and moisture is a potential source of mine drainage.
Similarly, waste pyritic materials in gob piles, spoil banks, or tail-
ings ponds will react with air and water to produce mine drainage. More-
over, after a particular mining operation is abandoned, mine drainage
will continue to be generated unless disturbed land is effectively
reclaimed and underground shafts and tunnels are properly shut down.
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(a) Formation of acid mine drainage; The chemical
reactions producing acid mine drainage are many. The most important,
however, are those involving the oxidation of pyrite. Mine drainage
from pyrite oxidation is generally shown as occurring in three steps;
(1) oxidation of pyrite to ferrous sulfate and sulfuric acid; (2) oxida-
tion of ferrous sulfate to ferric sulfate; and (3) hydrolysis of ferric
sulfate.
The oxidation of pyrite to ferrous sulfate and sulfuric
acid (step 1) is rapid if the pyrite is exposed to moist air.
Moisture condensation, flooding, and natural drainage
processes flush the ferrous sulfate-acid mixtures into watercourses,
where dissolved oxygen in the water will slowly oxidize the ferrous iron
to ferric iron (step 2). This oxidation may be catalyzed by other metals
(i.e., manganese, copper, and aluminum), or by bacteria (Ferrobacillus
ferroxidans).
Finally, as the ferric sulfate is diluted by a receiving
stream, it will be hydrolyzed to form colloidal ferric hydroxide (so-
called yellowboy) and sulfuric acid (step 3).
A detailed discussion of the pyrite oxidation sequence
outlined above may be found in Attachments C and D to Appendix C of the
Appalachian Regional Commission Report entitled Acid Mine Drainage in
Appalachia.38'39/
(b) Neutralization of acid mine drainage: It has long
been recognized that the above reactions are insufficient to char-
acterized mine drainage. For example, if the drainage passes through
a calcareous shale or limestone region, the acid will be neutralized
and converted into calcium (or magnesium) sulfate salinity.
Carbonic acid generated by the neutralization of acid
mine drainage will continue to dissolve limestone to produce calcium
bicarbonate, the material which provides the natural alkalinity of
practically all surface and subsurface waters.
The presence of bicarbonate alkalinity in neutralized
mine drainage has important ramifications. Some of this alkalinity
can be attributed to ferrous bicarbonate. Ferrous bicarbonate can
react with oxygen to form ferric hydroxide and carbon dioxide, thus
providing a mechanism for iron oxidation without the formation of
sulfuric acid.
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If mine drainage passes through noncalcareous clays and
shales, it may extract aluminum as aluminum sulfate. Aluminum sulfate
can hydrolyze to precipitate aluminum hydroxide and liberate sulfuric
acid, through reactions analogous to those with ferric iron.
Many clays contain alkali oxide (potassium or sodium
oxide) in significant quantities. A representative chemical analysis
of a Pennsylvania clay indicates 6.09% K20 and 0.177o Na20.— / The
presence of alkali oxide in clays provides a neutralization path for
acid mine drainage other than reactions with limestone or calcareous
shales.
(c) Mine drainage classes; Mine drainage has been
categorized into four classes.^/ These classifications are presented
in Table 5-1. Distinctions among the various classes are derived from
drainage pH (hence acidity), and from the oxidation state of the dis-
solved iron. The ratio of ferrous to ferric iron is an indicator of
the history of the mine drainage. A high ferric iron content may
indicate that the drainage has been exposed to air for a relatively
long time. The ratio may relate to location or condition of the drain-
age course, and thus may be potentially useful in prediction tools,
this aspect of mine drainage data interpretation has not been explored.
5.2.3 Other types of nonpoint pollutants arising from mining
operations: Sediment, leachates of various types (other than mine drain-
age) , radioactivity, and to a limited extent pesticides and fertilizers
are generated by mining activities, or as an aftermath to pollution from
mining is abetted by subsidence and fracture of geologic formations.
(a) Sediment from mining operations: Surface mining of
coal and other sedimentary minerals, e.g., phosphate and iron ore,
creates large areas of disturbed land. This disturbed land is highly
erodible and can contribute large quantities of sediment to surface
waters if the land is not properly reclaimed after mining or if proper
techniques for sediment control are not employed in the mining operation.
Processing raw minerals to concentrate ore creates vast
piles of finely divided raw materials, called tailings, which are poten-
tial sediment problems if not controlled at the processing site. This
problem is especially prevalent in the western United States where hard
rock minerals have been concentrated, and the resultant tailings are
spread over wide expanses of land.
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TABLE 5-1
MINE DRAINAGE CLASSES-
4/
pH
Class I
Acid
Discharges
2 - 4.5
Class II
Partially
Oxidized
and/or
Class III
Oxidized
and Neutralized
Neutralized and/or Alkaline
3.5 - 6.6
Acidity, 1,000 - 15,000 0 - 1,000
mg/1 CaC03
Ferrous Iron, 500 - 10,000 0 - 500
mg/1
Ferric Iron,
mg/1
Aluminum,
mg/1
Sulfate,
mg/1
0
0 - 2,000
0 - 1,000
0-20
6.5 - 8.5
Class IV
Neutralized
and not
Oxidized
6.5 - 8.5
50 - 1,000
1,000 - 20,000 500 - 10,000 500 - 10,000 500 - 10,000
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Thus, sediment is a problem common to most mining opera-
tions. The nature and extent of the problem is dependent upon the
geographical location of the mining operation, the type of mining em-
ployed, the type of mineral being extracted, and the degree of reclama-
tion, including establishment of vegetative cover, used to restore
land disturbed by the mining operation.
The following discussion is concerned with sediment from
two sources: surface mining of coal, and tailings from hard rock mineral
processing.
Sediment from surface mining of coal: Contour min-
ing of coal is the largest single source of sediment from mining opera-
tions. Attention has been drawn to this problem because of Congressional
inquiry into surface mining.10-13/ Surface mining of coal increased
from 7.7 million metric tons (8.5 million tons) in 1920 to 135 million
metric tons (149 million tons) in 1947, and to 235 million metric tons
(259 million tons) in 1971.^2J The percentage of total coal production
using surface methods was 1.5% in 1920, 22.1% in 1947, and 46.9% in 1971.
Sediment problems in mountainous coal-mining areas
arise primarily because it is difficult to restore a mountainside
excavated to extract its coal values. Traditional contour mining
practices have involved the dumping of overburden on the downslope side
of the cut in order to expose the coal seam. The material exposed by
this indiscriminate dumping is often highly erodible, and can result
in excessive siltation of mountain streams and reservoirs.
In addition to downslope dumping of spoil, contour
mining also leaves a "highwall," the steep cliff remaining above the
cut after coal has been stripped. Highwall materials can erode and
deliver sediment to local watercourses, unless runoff is diverted into
drainage channels along the top of the cut. If the land is restored
to the original contour, no highwall remains.
Siltation from surface coal mining operations in
flat country (area coal mining) is less acute than from surface mining
in mountainous or hilly regions.
Hard rock mineral processing: The concentration
of ore from hard rock mining areas results in large quantities of tail-
ings—waste rock dust removed from the raw ore. Ore-concentrating
operations are usually aqueous, and waters containing tailings have in
the past been indiscriminately dumped into the nearest stream. This
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practice has resulted in many miles of sediment-laden stream valleys in
the West. In cases where tailings have been impounded, sediment does
not constitute a mining pollutant problem.
One case study on the effects of uncontrolled tail-
ings discharges has been conducted along Whitehead Creek in South Dakota.—'
This creek serves as the water supply to the Homestake Gold Mine at
Lead, South Dakota. Through the years, Whitehead Creek below the
Homestake Mine has become sediment clogged. Sediment from the opera-
tion can be traced from the mine to the Missouri River 300 miles away
along the courses of the Belle Fourche and Cheyenne rivers, of which
Whitehead Creek is a tributary.
(b) Groundwater pollution from mining operations; In
many parts of the country, groundwater is a principal source of water
for domestic and industrial use. Mining operations often involve
processes which disrupt the flow of groundwater.
Blasting operations can fracture local rock strata.
These fissures in the bed rock provide entries for mine drainage or
saline water to aquifers containing good groundwater.
The sinking of mine shafts or the digging of deep open pit
mines can create depressions which are lower than normal groundwater
levels. In this event, groundwater will drain into the depressions. In
active mining operations, this water must be removed to gain access to
the mineral deposit.
In hard rock mining areas, some ores are leached with
sulfuric acid to dissolve a metal so that it can be concentrated in a
subsequent process. This separation technique, known as leach mining
or solution mining, is often employed for the extraction of copper.
In the leaching process,the dissolution of copper occurs in ponds which
may be located on fractured rock. Leach liquor can seep from these
ponds into groundwater, thus polluting it.—'
When leach mining is employed in areas that receive
little rainfall, e.g., Arizona, great care is usually taken to insure
that water is conserved. Any losses of leach liquors to groundwater
require make-up water, which could be difficult to obtain. In these
areas, pollution of groundwater from leach mining operations should
be small.
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Leachate from tailings ponds located on fractured rock
also are potential sources of groundwater pollution. This aspect is
discussed in greater detail in the next section
In general, groundwater pollution from mining operations
is controllable by sealing or lining the ponds containing polluted water.
(c) Leachate from mining operations; Leachate, the dis-
charge of polluted water arising from water percolation in waste rock
piles, is a serious source of pollution. It occurs in coal mining
regions where coal refuse, gob piles, and mine spoil are exposed to
weathering, and in the West where tailings piles and leach-mining opera-
tions are located on fractured rock.
Pyritic wastes in gob piles or in unreclaimed overburden
(spoil banks) are serious sources of leachate. The pyrite in these
piles will oxidize and form soluble iron salts and sulfuric acid within
the pile. Under normal circumstances, these oxidation products remain
in the pile until it is flooded with water during a rainstorm. When
excess water runs through the pile, the "flushout" phenomenon occurs,!./
i.e., acid and salt dissolve in the storm water and runoff into nearby
surface waters. Thus, stream water quality can be severely deteriorated
as a result of heavy rainfall in mining areas.
In addition to the flushout of pyritic oxidation products,
rainfall and its subsequent runoff create fresh surfaces in the piles.
The fresh surface permits the regeneration of oxidation products until
the next rain, at which time the flushout process is repeated. Thus,
waste piles are continuous "chemical factories" for the production of
mine drainage.^2.'
In hard rock mining areas, tailings piles are often
located on fractured rock which is inadequately sealed. Thus, water
percolating through tailings piles can dissolve residual salts and be
transmitted into groundwater supplies through the fractures or into
surface waters as springs at the foot of the pile. The severity of
the problem hinges on the adequacy of water supply at the processing
site. If process water is abundant, then it can be wasted along with
tailings. If water is in short supply, then it must be conserved and
reused in the mining operation.
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Water associated with the mineral deposits in hard rock
mining areas is often contaminated with heavy metals. For example,
water in parts of Nevada contain arsenic arising from natural sources.^/
Indeed, many of the mineral lodes in the West were discovered by trac-
ing water polluted by natural leaching of minerals.
Control of leachate pollution from tailings piles is
often hampered by the desire to save tailings for future mineral ex-
traction. In the concentration process, it is impossible to remove
all of the mineral values. Therefore, some mining companies stockpile
tailings in the expectation that they can be reprocessed economically
in the future. As a result, some tailings piles have existed 50 years
or more without adequate maintenance. Seals between the pond and bed-
rock have deteriorated, and piles have eroded by water and wind. Thus,
the effort to conserve mineral values has created sources of pollution.
The disposal of tailings into creeks has resulted in
sediment deposits from which chemicals can leach readily into ground-
water and surface water supplies. The Homestake Mine discharges into
the Whitehead Creek and Cheyenne River basins are a case in point.2h.l
These tailings contain mercury in the waste, since mercury is a reagent
in the extraction of gold. Thus, toxic materials used in concentrating
minerals can find their way into tailings and hence into water supplies.
(d) Radioactivity from mining operations: Radioactivity
arising from mining activities is primarily a long-range concern in the
western United States, especially with regard to increased mining activi-
ties and control of seepage of uranium and radium from mill tailings at
sites where uranium ores are mined and processed. Although concentrations
approximating the maximum permissible concentration limits (MPCy) have
been recorded in water systems excluded from general public use, in the
majority of radioactive monitoring data, MPC^ limits for radionuclides in
public water supplies have not been approached. The effects of very long-
term exposure to low levels of radioactivity are not known, however.
Region VIII of the Environmental Protection Agency has
conducted two studies concerned with disposal of radioactive tailings.
Those studies are: Disposition and Control of Uranium Mill Tailings
Piles in the Colorado River Basin,zU and Environmental Evaluation of
Mines Development, Inc., Uranium and Vanadium Milling Operations at
Edgemont, South Dakota.£=L-' In both of those studies, the need for a
conservative approach to tailings disposal was emphasized, even though
permissible radiation levels were not exceeded.
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A Radium Monitoring Network has been established in the
Colorado River Basin. ^£/ In the several years that this network has
been in operation no excessive amounts of radioactivity have been found
in the water,
Radioactivity has been discovered in mine drainage in
the Kiskiminetus River, a. tributary of the Allegheny River in Pennsylvania.—'
Data clearly show that radioactive nuclides are present in mine drain-
age and in receiving waters downstream from the drainage source. The
radioactivity increases are noted only in mining areas, indicating that
the mining operations are responsible.
In many coals, uranium is a trace metal associated with
the coal. In Western Pennsylvanian coals, uranium contents range from
10 to 140 ppm. In eastern Pennsylvania, some coal deposits contain up
to 3,000 ppm (0.37o) of uranium oxide,
While there is limited information available on Western
coals, it is known that there is uranium present. Because of peculiari-
ties of Western coal, uranium and the other constituents may be of some
environmental consequence.
(e) Nutrient and pesticide pollution from mined land
reclamation: Effective reclamation of land disturbed by mining activi-
ties requires usage of fertilizers and pesticides to promote vegetative
stabilization. These materials are potential pollutants, to an extent
governed chiefly by the care exercised in their use.
(f) Subsidence from abandoned underground mines; A special
environmental aspect of mining operations is subsidence in abandoned
underground mining areas. Subsidence is the caving-in of abandoned
underground excavations resulting in instability of ground overlying the
excavation. In many parts of the country, usage of land over undermined
areas is hindered because of subsidence.
A compilation of areas of the country where mine subsidence
exists is shown in Table 5-2. This table has been entered into the record
of hearings concerning surface mining legislation held before the U.S.
Senate Subcommittee on Minerals, Materials, and Fuels of the Committee
on Interior and Insular Affairs, 92nd Congress, First Session. .1!'
173
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TABLE 5-2
UNDERGROUND MINES IN URBAN
Alabama Coal and iron mines: adjacent to Birmingham
Arizona Copper mines: Bisbee and Jerome
Arkansas Coal mines: Hartford, Montana, Paris and Spadra
Colorado Coal mines: Dacona, Firestone, Frederick, Lafayette
and Louisville
Lead-zinc mines: Leadville
Idaho Coal, silver, lead and zinc mines: Burke, Gem, Kellogg,
Mullan, Murray and Smelterville
Illinois Portions of cities and towns probably underlain by mines
include: Belleville, Carbondale, Centralia, Danville,
Decatur, Harrisburg, Herrin, Johnston City, Marion,
Mount Vernon, Springfield, West Frankfort and Zeigler
Lead -zinc mines underlie Galena
Indiana
Iowa
Kansas
Coal mines: Ashboro, Augusta, Boonville, Brazil, Carbon,
Centerpoint, Chandler, Bugger, Evansville, Fort Branch,
Francisco, Gibson, Hymera, Kings, Knightsville, Linton,
Newburgh, New Geshen, Petersburg, Seelyville and
Yankeetown
Coal mines: Boone, Centerville, Des Moines, Knoxville,
Oskaloosa and Ottumwa
Zinc-lead mines: Galena and Treece
Limestone mines: Kansas City
Coal mines: Alma, Atchison, Burlingame, Cherokee,
Croveburg, Franklin, Frontenac, Lansing, Leavenworth,
Mineral, Mulberry, Osage City, Pittsburg, Pleasanton,
Scammon, Scranton, Weir and Williamsburg
Salt mines: Hutchinson, Kanopolis, and Lyons
Kentucky Coal mines: Madisonville
Limestone mines: Lexington
174
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TABLE 5-2 (Continued)
Maryland
Michigan
Dimension stone mines:
Coal mines: Frostburg
Cardiff
Minnesota
Missouri
Montana
Nevada
New Jersey
New York
Ohio
Iron mines: Bessemer, Iron River, Ironwood, Ishpeming,
Negaunee and Wakefield
Salt mines: Detroit
Gypsum mines: may be under Grand Rapids
Copper mines: adjacent to and probably underneath Calumet,
Hancock and Houghton
Iron mines: Aurora, Biwabik, Chisholm, Eveleth, Ribbing
and Keewatin
Zinc-lead mines: Alba, Aura, Caterville, Duenweg, Neck
City, Oronoga, Purcell, Webb City and Wentworth
Lead mines: Annapolis, Boone Terre, Desloge, Doe Run,
Flat River, Leadington, Leadwood, Valles Mines and
Viburnum
Coal mines: Bevier, Brookfield, Bucklin, Gainsville,
Cameron, Carrollton, Clifton Hill, Deepwater, Elmira,
Farber, Huntsville, Kansas City, Kingston, Kirkville,
Knoxville, Lexington, Macon, Marceline, Melbourne,
Milan, Mindenmines, Missouri City, Montgomery City,
New Cambria, Richmond, St. Louis, Trenton, Vibbard,
Waverly, Wellington, Windsor and Winston
Clay mines: Deppwater and St. Louis
Limestone mines: Carthage, Kansas City and Neosho
Sandstone mines: Crystal City
Copper mines: Butte, Centerville and Walkerville
Gold and silver mines: Tonepah and Virginia City
Iron mines: Dover, Hibernia, Mine Hill, Ringwood,
Rockaway and Wharton
Iron mines: Lyon Mountain, Mineville and Witherbee
Coal mines: may underlie some urban areas in the
southeastern portion of the State
Salt mines: Cleveland
175
-------
Oklahoma
TABLE 5-2 (Continued)
Coal mines: Bokoshe, Broken Arrow, Coalgate, Coalton,
Cottonwood, Dewar, Haileyville, Hartshorne, Henryetta,
Krebs, Lehigh, McAlester, McCurtain, Tulsa and Wilburton
Zinc-lead mines: Cardin, Commerce, North Miami, Peoria,
Picher and Quapaw
Oregon
Pennsylvania
Coal mines:
Iron mines:
Coos Bay
Oswego
Anthracite mines: The Anthracite region and particularly
the northern Anthracite field including Scranton and
Wilkes-Barre
Bituminous mines, portion of the following urban areas are
undermined: Brownsville, Cannonsburg, Charleroi, Donora,
Metropolitan Pittsburgh, Monongahela and Uniontown
South Dakota Gold mines: Lead
Virginia Gypsum mines: Plasterco
Coal mines: Norton
Washington Coal mines: Bellingham, Black Diamond, Carbonado,
Centralia, Chehalis, Cle Elum, Issaquah, Newcastle,
Ravensdale, Renton, Ronald, Roslyn and Wilkeson
Iron mines: Hamilton
Gold mines: Chewelah, Republic and Wenatchee
Lead-zinc-silver mines: Leadspoint and Metaline
West Virginia Coal mines: Barrackville, Bartley, Bradshaw, Fairmont,
Fairview, Farmington, Grant Town, Monongah, Rivesville
and Welch
Wisconsin Lead-zinc mines: Benton, Hazel Green, Mineral Point,
New Diggings, Platteville, Shullsburg and Tennyson
Iron mines: Hurley and Montreal
Wyoming Coal mines: Reliance and Rock Springs
176
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TABLE 5-2 (Concluded)
"Based on the incidence of subsidence in the past, it is estimated that
because of existing instability, some 750,000 surface areas of the re-
maining undermined 6 million acres will have been affected by subsidence
by the year 2000. The amount of land that is expected to subside as a
result of mining beneath an additional 5 million acres over the 1966-
2000 period is 1,720,000 acres. The estimated total subsidence expected
to occur between 1966 and the year 2000 therefore amounts to about
2.5 million acres. Remedial action to lessen subsidence incidents
through backfilling and improved support techniques during actual
mining operations in the future would tend to reduce the potential."
177
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5.2.4 Sources of mining-related pollution: Pollution from
mining activities can arise from several sources. It can come from
active mining operations with inadequate controls; from inactive mining
operations improperly shutdown or abandoned with no attempt at reclama-
tion; or from the unique set of conditions peculiar to the geography
and climate adjacent to the mining operation. In addition, the nature
and extent of the pollution from mining depends upon the particular
mineral deposit, the type of mining used to extract the mineral, and
the length of time that the particular deposit has been mined. The
mining operation (surface versus underground) and the age of the mining
activity are primary considerations in assessing the nature and extent
of pollution.
The most noted sources of pollution from mining are those
associated with coal. Coal has been the primary energy source in the
United States for many years, as reflected in coal production statistics.
Since 1920, approximately 23 billion metric tons (25 billion tons) of
bituminous coal and 2.2 billion metric tons (2.4 billion tons) of anthra-
cite coal have been mined.—' In 1971, over 500 million metric tons
(550 million tons) of bituminous coal were mined; 46.9% was obtained
through surface mining methods, 3.1% by auger methods, and 5G.070 by
underground methods. The tonnage of coal mined annually will undoubtedly
increase in the future, especially since resources of other fossil fuels
(petroleum and natural gas) are becoming increasingly limited.
The coal mining pollution problems have been extensively char-
acterized for the Appalachian Region of the United States. The Appa-
lachian Regional Commission has published a six-volume report on mine
drainage-^' in which a very detailed account of the nature of mine drainage
and its effect upon the economy of Appalachia are presented. While this
report deals specifically with one problem in a specific area, it is of
general interest as an outline of the data inputs needed in any study
to establish environmental consequences of mining operations.
In recent years, demands for clear air have created increased
mining activity in low-sulfur coal deposits in the Northern Great Plains
(Wyoming and Montana). The pollution problems associated with coal
mining in the western United States have not been extensively charac-
terized. However, any pollution arising from these operations will be
considerably different from the problems found in Appalachia. The de-
posits are low in sulfur; hence, they should be less prone to generate
acid mine drainage. The deposits are located in a semi-arid region;
hence, less water is available for transporting pollutant away from the
operation. On the other hand, the mining of Western coal deposits may
178
-------
adversely affect local groundwater, the principal source of fresh water
in the region.
This section will present details of some mine drainage pol-
lution problems in Appalachia. In addition, the following pollution
sources will be discussed in less detail: hard rock minerals; stone,
sand, and gravel; noncoal sedimentary minerals; and oil and gas.
(a) Coal mine drainage in Appalachia: An accurate
assessment of mine drainage sources in Appalachia is difficult, since
the sources are constantly changing. The coal mining industry is tak-
ing steps to improve mining operations in order to minimize pollution
potential in active mines, and together with governmental agencies (federal,
state, and local) is engaged in activities to stem pollution from in-
active and abandoned mining sources. As a result, the nature and ex-
tent of the coal mine drainage problem in Appalachia constantly shifts
from year to year.
The following discussion is based upon sets of data which
are less than 5 years old, but are already considered to be outdated.
The data are presented because of the depth and completeness, and be-
cause they illustrate problems encountered in characterizing mine-related
pollution so that planning can be initiated. The methodology used in
Appalachia may be useful to responsible persons in other parts of the
country where mining pollution is less well characterized.
In the Appalachian Region, mine drainage emissions have
not been noted at many coal mining operations. The volume of mine
drainage emitted by active and inactive operations varies widely from
mine to mine and from watershed to watershed. Tybout—' has listed the
number of bituminous coal mines in 32 Pennsylvania coal producing
counties, and has totaled the amount of drainage coming from several
sources in each county. This tabulation is presented as Table 5-3. The
tabulation shows that 2,300 of 4,716 underground mines and 3,613 of the
8,246 surface mines reported mine drainage.
Another important feature of Table 5-3 is the number of
mines with "unknown" drainage. An unknown source in Table 5-3 refers
to a mine for which no drainage data were available during Tybout1s
survey. Of the 4,716 underground mines, drainage data for 999 mines
were "unknown." Drainage for surface mines was less well defined; 3,892
surface mines out of a total of 8,246 had no information concerning
drainage.
179
-------
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mine drainage at the same rate as inactive mines in the particular
county, the absolute accuracy of the mine drainage volumes attributed
to inactive mines may be questioned. Nevertheless, the information
is a valid base for assessment, planning, and implementation of remedial
action since 1968. Progress between 1968 and 1973 has defined the
situation more clearly, and updated data for the Pennsylvania bituminous
coal producing counties could be very different.
The Appalachian Regional Commission report entitled
Acid Mine Drainage in Appalachia-^' has addressed mine drainage sources
from a different direction. This report contains data on the amount
of acidity emitted to various watersheds based upon known drainage
sources in specific watersheds in Northern Appalachia. The Appalachian
Regional Commission data are presented in Table 5-4.
The data shown in Table 5-4 represent known mine drainage
sources. Thus, the total number of sources included in the study is
less than the total number of active and inactive mines in the region.
The acid emitted by active and inactive mines in various parts of
Northern Appalachia varies, as shown by Table 5-4, markedly from one
watershed to another. The high degree of variance makes it difficult
to define a "typical" mine drainage source, and indicates that the
nature and extent of mine drainage is quite dependent upon local geo-
graphical and geological conditions.
Since publication of the Appalachian Regional Commission
report on mine drainage, many of the mine drainage sources have been
and are being brought under control. A current compilation of data
would be quite different than the 1969 compilation. Studies of the
type conducted by the Appalachian Regional Commission, thus serve to
define specific localities with mine drainage problems, provide a
quantitative basis for planning, and provide a yardstick for measur-
ing progress toward elimination of problem areas.
(b) Hard rock minerals: Hard rock mining is extensive
in the western United States. Ores obtained from hard rock mining
areas are usually associated with pyrite, hence the mining operations
are potential producers of acid similar to that from coal operations.
In addition to ordinary pyritic materials, the hard rock ores are as-
sociated with heavy metals, so that the acid formed can contain sig-
nificant quantities of toxic metals. In the Central Rocky Mountains,
the elements copper, zinc, and arsenic are almost always associated
with mine drainage. In the Central City region of Colorado, streams
draining abandoned workings can contain up to 5 mg/liter of copper,
5 mg/liter of zinc, and 2 mg/liter of arsenic.ft=L/ The copper and
182
-------
TABLE 5-4
SELECTED INFORMATION FOR ACID MINE DRAINAGE SOURCES IN NORTHERN APPALACHIA-/
Underground
Subarea
Sources
Surface
Combined^/
Other Sources'
Sources
.£/
Total
Sources Acidity
Active Mining Operations
Anthracite Area
Susquehanna Basin 36 47,450
Delaware Basin 4 1,040
Tioga River
West Branch Susquehanna 19 4,770
Juniata River
Allegheny River
Clarion River
Kiskiminetas River
Monongahela River
Ohio River Tributaries
Wheeling Creek
Raccoon Creek
Capatina Creek
Total Active Sources
Inventoried 278 229,082
Inactive Mining Operations
17
930
75 10,581
24
22,620
28
4,947
36
4
36
405
47,450
1,040
5,700
4
31
175
2
•-
7
50
54,450
121,400
51
--
-129
3
5
49
__
1
--
480
190
8,950
__
31
--
1
--
23
—
--
--
120 1
1
22,500 23
-.
1
2
22
31
2,190
„
324
2,380
9
37
270
2
2
9
672
54,671
155,040
,j
355
2,251
267,230
Anthracite Area
Susquehanna Basin
Delaware Basin
Tioga River
West Branch Susquehanna
Juniata River
Allegheny River
Clarion River
Kiskiminetas River
Monongahela River
Ohio River Tributaries
Wheeling Creek
Racoon Creek
Capatina Creek
Total Inactive Sources
Inventoried
73
41
15
450
44
145
381
1,619
41
31
3
144,500
9,440
8,100
99,400
14,140
12,380
158,100
168,900
1,990
21,350
50
3
3
7
267
--
240
155
749
12
69
--
336
112
900
39,020
--
34,560
4,930
43,340
288
11,230
--
--
--
--
--
--
57
107
249
16
39
--
--
--
--
--
--
7,000
9,730
41,500
2,830
27,660
--
1
--
--
104
--
40
84
8
1
1
--
37
--
--
41,960
--
2,650
38,180
3,350
49
23
--
77
44
22
931
44
482
727
2,625
70
140
3
144,873
9,552
9,000
180,380
14,140
56,590
210,940
257,090
5,157
60,263
50
2,953
Total Sources Inventoried 3,231
638.350
867,432
1.505 134.716
1,580 145,297
468
492
88.720
111,340
239
267
5,165 948,035
5,570 1,215,265
a/ Acidity is measured as net acidity in kilograms of CaC03 equivalent per day.
b_/ Combined sources are those sources including both surface and underground mines.
c_/ Other sources are primarily coal processing plants in active mines and mining refuse piles for inactive mines.
* Note: Adapted (from Ref. 4).
General Notes: This information includes virtually all of the source inventory data obtained by FWPCA for the region
during 1964-1969. TheFWPCAhas estimated that the areal coverage accounts for 75% of the acid mine
drainage formed in the region. The number of sources shown represents that portion of the identified
mine sites which were producing mine drainage at the time of inventory. Since most sites were
inventoried during the summer, the sources do not include those which are seasonal. There appears to
be many more mine sites than identified sources. For instance, the Monongahela Basin inventory
identified over 7,000 mine sites, but only 2,895 were producing mine drainage when surveyed.
183
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arsenic levels are higher than permissible surface water criteria (1.0
mg/liter of copper and 0.05 mg/liter of arsenic) for public water
supplies. In addition to copper, zinc, and arsenic, some hard rock min-
ing areas will add lead, antimony, cadmium, mercury, and other heavy
metals to water supplies.
Mining sources in the San Juan Mountains of Colorado
have been identified with respect to their contribution to the salinity
of the Colorado River.—' It was found that mine drainage contributes
approximately 18 metric tons (20 tons) daily of dissolved solids to
the Dolores and San Miguel rivers, and ultimately to the Colorado River.
Springs and salt seeps in the area emit about 630 metric tons (695 tons)
of salt per day to the Colorado River Basin. Summaries of the San Juan
Mountain mine drainage sources are available for review in the Environ-
mental Protection Agency Region VIII Offices in Denver, Colorado.—/
A study now being conducted in Colorado concerns "Effects
of Mining on Surface Water Quality Exclusive of Uranium Mining in
Colorado."£i/ This study is being conducted for the State of Colorado
by the Water Resources Division (Colorado Division) of the U.S. Geologi-
cal Survey. This study will be used to identify streams which are af-
fected by mining operations in Colorado, and suggest monitoring sites
for continued data acquisition. The Colorado study, when it is published,
should serve as a model for other states in recognizing the sources and
types of stream pollution arising from mining operations.
A third study, entitled "Water Quality Considerations
for the Metal Mining Industry in the Pacific Northwest1,1^!/ was chiefly
concerned with water pollution at active and abandoned mines. The re-
port presents suggestions and recommendations for minimizing the effects
of mining on water quality. This study addresses itself specifically
to mine problems in Region X of the Environmental Protection Agency.
Hard rock mining activities located above the timber
line in the western United States have unique pollution problems,
since it is very difficult to restore disturbed land where natural
conditions do not promote rapid revegetation. In addition, mine-
related activities such as haul roads tend to create more serious
pollutant-generating conditions than similar activities at lower eleva-
tions. The pollution generated from mining activities above the timber
line is being investigated at Goose Creek, Montana, by Region VIII of
the Environmental Protection Agency.22J
184
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The problems associated with sediment discharges from
the Homestake Mine (gold) in Lead, South Dakota,1ft/ and their deposi-
tion in the Cheyenne River Valley have been discussed briefly earlier
(Section 5.2.3a, c).
(c) Stone, sand and gravel: The production of stone,
sand, and gravel constitutes the largest volume of materials from min-
ing activities in the United States. In 1971, 792 million metric tons
(873 million tons) of stone were quarried, and 884 million metric tons
(920 million tons) of sand and gravel were dredged.5~t' This tonnage
is 397o of all mined materials in 1971.
Definitive information concerning the pollution from
stone, sand, and gravel operations is not readily available. Evaluation
of the pollution potential from dredging operations (the common tech-
nique used to mine sand and gravel) has been conducted in a study
which parallels the study reported in the present document.
(d) Noncoal sedimentary mineral operations; In addi-
tion to coal, several other sedimentary minerals are mined in the
United States. Important products include clay, phosphate rock, iron
ore, and uranium. These products are usually mined by surface methods,
and hence are potential sources of sediment. The nature of the opera-
tions is such, however, that sediment is controlled at the mining site.
The quantity of waste material generated by ore concentration processes
is usually much greater than the mineral values recovered. Thus, a
major operational problem lies in the management of the wastes. In
the case of phosphate rock, 1-1/4 hectares (acre) of land is required
to contain the waste from 1 hectare (acre) of mined rock..1ft/
As has been discussed in Section 5.2.3, disposal of uranium
tailings is a possible source of radioactivity in water supplies.
(e) Oil and gas; Abandoned oil and gas wells are con-
tributors of salinity to water supplies. The discharges often arise
from inadequate sealing, or from seal deterioration over the years.
Oil and saltwater discharges observed-t?-/ from the El
Dorado Oil Field in Central Kansas illustrate the general nature of
this problem. During a 3-month period in 1971, eight salt springs
arising from abandoned oil wells erupted along a 3-mile stretch of a
stream. These eruptions were apparently caused by two factors. First,
hydraulic pressure is being applied to the field in order to recover
oil values; weak seals on abandoned wells can thus rupture and discharge
185
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salt water. Second, several salt springs from abandoned oil wells on
adjacent properties were resealed; the resealing resulted in a change
of the local hydraulic pressures, and permitted new leaks to occur at
the weakest points.
Saline water seeps in the vicinity of Meeker, Colorado,
were noted in 1970.—' This area contains several wells drilled in-
termittently since 1915 for oil exploration purposes. The seepage was
of special concern, since it occurred less than 2 years after wells in
the area had been plugged. It was concluded that "plugging of all
wells that intercepted aquifers has removed the artifical pressure re-
lief channels formed by the unplugged wells such that natural saline
groundwater is again under sufficient pressure to force it to the sur-
face through natural fractures in a manner similar to that existing
prior to the drilling. Replugging the wells will not achieve a reduc-
tion in seepage if these fractures intercept the aquifers as they
appear to do."
5.2.5 Statistics for mining activities: The nature and
extent of pollution sources from mining will constantly change as old
mineral deposits are worked out and new mineral deposits are opened.
This section presents statistical information on inactive and abandoned
mines, and sources of current statistics on active mining operations.
(a) Inactive and abandoned mines: The number of inactive
and abandoned underground mines has been listed (Table 5-5) in an un-
published U.S. Bureau of Mines studyii/ concerning environmental ef-
fects of underground mining. Pollution outputs from those inactive
and abandoned mines is unknown. It is known that many abandoned under-
ground mines in Northern Appalachia do not emit mine drainage (see
Section 5.2.4, Table 5-3).
This list is incomplete, especially regarding abandoned
mines in the western United States. Throughout the West, many prospector
pits have been dug which never yielded valuable minerals. These pits
have been abandoned, and have left holes in the ground with adjacent
piles of rock spoil. It is estimated that there are over 10,000 abandoned
prospector pits in Colorado alone.—'
Inactive and abandoned surface mining operations are
also sources of pollution. The U.S. Department of the Interior con-
cluded an extensive study, in the mid-1960's, of pollution arising from
surface mining.22.' The report contains statistics (as of 1965) pertain-
ing to land disturbed as a result of various surface mining operation in
the United States. A list of disturbed land acreage by commodity and
state presented in their report is reproduced as Table 5-6.
186
-------
TABLE 5-5
ABANDONED AND INACTIVE UNDERGROUND MINES
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Total
IN THE UNITED STATES
Coal
310
6
--
269
32
565
--
--
--
115
--
11
1,605
960
1,138
528
12,045
--
--
564
--
--
--
1
466
334
--
5
--
--
48
--
5
--
2,187
251
61
7,824
--
--
1
2,931
21
44
--
14,397
247
20,616
--
26
67,613
AS OF 1966JL3/
Metal
64
--
773
186
3,045
1,699
6
--
--
62
--
1,749
39
--
60
681
4
--
7
7
7
278
87
--
1,520
1,691
--
1,346
24
26
277
61
78
12
35
283
1,140
160
2
30
172
42
31
1,348
17
14
907
--
389
295
18,654
Nonmetal
27
6
82
7
3
28
208
124
2
13
120
1
1
6
1
36
146
10
3
23
17
1,129
53
3
55
4
17
11
3
6
52
9
1
2,215
187
-------
TABLE 5-6
LAND DISTURBED BY STRIP AND SURFACE MINING IN THE UNITED STATES
AS OF JANUARY 1, 1965, BY COMMODITY AND STATED/
State
Alabama8./
Alaska^/
Arizona3/
Arkansas^/
California-
Colorado3./
Connecticut-/
b/
Delaware-
Florida!/
Georgia
Hawaii-/
Idaho^/
Illinois-/
Indiana^/
Iowa.3./
Kansas
Kentucky
Louisiana3./
Maine3./
Maryland
Massachusetts3./
Michigan^/
Minnesota3.'
Mississippi^/
Missouri-'
Montana^/
Nebraska^/
Nevada-
New Hampshirek/
New Jersey—'
New Mexico^/
New York3./
North Carolina3./
North Dakota
Ohio . .
b/
Oklahoma—
Oregon^/
Pennsylvania
Rhode Island3./
Clay
4,000
_»
2,700
600
2,700
2,000
—
200
13,200
1,300£/
~-
500
1,400
1,500
1,300
I.IOQ3/
2,400aJ^/
900
400
l,200£ii/
700
600
600
2,700
6,600
_.
900
100
—
1,400
13
1,700
5,800
8003-/
10.2003/
100
10,400s./
Coal
(Bituminous,
Lignite and
Anthracite)
50,600
500
..
10,100
20
2,800
—
_-
__
300^
__
127,000
95,200
11,000
45,60Qb/
119,200^-'
__
__
2,200b-/
—
—
--
31,800
1,500
—
--
1,200
—
10
212,800k/
23,500
302,400t/
—
South Carolina3-/ 10. 900
South Dakota
Tennessee^/
Texas-/
Utah^/
Vermont
Virginia
Washington-
West Virginia^/
Wisconsin—'
Wyoming
2,000£/
2,700
6,800
600
1>10o2i^/
500
300
100
S.SOO3^/
Total 108,513
900t/
29,300
2,900
.._
__
29,80c£/
100
192,000
—
i.oook/
1,301,430
(Acres)
Stone
3,900
.•
1,000
900
8,000
6,200
100
200
25,300
6,800£/
--
700
5,700
10,200
12,200
7.500S/
3,900l/
100
4,400
2,200f/
1,200
7,700
3,900
400
8,400
10
4,300
1,600
100
2,000
100
12,500
6,000
300]>/
21.000S/
—
300
24,400s'
20
1,400
—
4,400
21,900
200
2,300k/
4.3002/
1,300
2,800
9,000
3003ib_/
241,430
Sand and
Gravel
21,200
2,000
7,200
2,600
Phosphate
Gold Rock
100
8,600
1,200
-_ _-
19,900 134,000
15,500
16,100
5,200
3,900
1,200£/
__
11,200
9,000
18,000
17,600
5,100i/
1.7003./
29,700
28,200
18,800£/
36,400
25,200
41,600
26,500
3,800
13,500£/
23,700
5,500
8,000
27,600
400
42,200
18,400
26.1003./
28, 1003/
2.500S/
1,300
23.8003/
3,600
10,400
28,OOCl£/
18,400
122,300
2,200
4.0001/
13, 1003/
5,700
300
26,400
?nna,b/
823,300
17,100
—
__ __
143,600
—
-- _^
21,200 3,100
--
--
--
—
--
12
__
—
—
3
..
—
5,600 100
—
5,600
--
„
40
5
2,200 300
—
—
—
6,300
_-
200 8,100
--
27,000
—
10
—
6003./ 1003/
400
-.
5
800b/
203,167 183,110
Iron Ore
52,600
...
—
100
900
25
--
100
__
ioo£/
__
35
6
—
—
50
100
20£/
1,100
2,200
67,700
30
200
10
—
600
--
1,000
100
700
100
--
4,000a,/
--
10
8,800f/
--
100
—
5,300
9,600
500
--
7 , 700a.b
20
100
49
oQQajb
164,255
All Other
1,500
._
20,300
8,100
8,500
11,400
100
10
2,800
12.000S/
10
4,200
--
400
2,300
20Q3./
500£/
_.
1,700
8001/
900
1,200
1,600
—
8,300
6,200
—
19,500
200
1,800
4,600
600
4,000
2,0002/
600a/
1,400
1,400
--
1,600
3,300W
13,800
2,800
2,000
400k/
/ 4,100lii
—
--
--
/ 4,30()t/
162,620
Total
133,900
11,100
32,400
22,400
174,020
55,025
16,300
5,710
188,800
21,7003./
10
40,935
143,100
125,300
44,406
59,500
127,700
30,750
34,812
25,220
40,300
36,900
115,403
29,630
59,100
26,920
28,900
32,900
8,300
33,800
6,453
57,705
36,810
36,900
276,700
27,400
9,410
370,202
3,620
32,700
34,200
100,900
166,300
5,510
6,700
'J (-0,800
8,820
195,500
35,554
10,400
3,187,825
a/ Data obtained from Soil Conservation Service, U.S. Department of Agriculture.
b/ Data compiled from reports submitted by the States on U.S. Department of the Interior form 6-1385X.
cl Estimate.
188
-------
TABLE 5-6 (Concluded)
LAND DISTURBED BY STRIP AND SURFACE MINING IN THE UNITED STATES
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wiscons in
Wyoming
Total
AS OF JANUARY 1, 1965, BY COMMODITY AND
Clay
1,600
-
1,100
240
1,100
800
80
5,300
530
-
200
570
610
530
450
970
360
160
490
280
240
240
1,100
2,700
--
360
40
--
570
5
690
2,300
320
4,130
-
41
4,210
--
4,410
810
1,090
2,800
240
•-
450
200
120
40
1,420
3,896
Coal
(Bituminous
Lignite and
Anthracite)
20,500
200
4,100
8
1,130
--
•-
-
120
--
--
51,400
38,500
4,500
18,500
48,200
-
--
890
-
.-
•-
-
12,900
607
-
---
490
--
4
3,100
86,100
9,500
--
122,400
360
11,900
1,200
--
12,100
40
77,700
--
405
526,854
STATE
(Hectares)
Stone
1,600
-
400
360
3,200
2,500
40
81
10,200
2,800
--
280
2,310
4,130
4,900
3,000
1,600
40
1,800
890
490
3,100
1,600
160
3,400
4
1,700
650
40
810
40
5,060
2,400
120
8,500
-
120
9,870
8
570
--
1,800
8,900
81
930
1,700
530
1,100
3,600
120
97,534
Sand and
Gravel
8,600
810
2,900
1,100
8,100
6,300
6,500
2,100
1,600
490
-
4,500
3,600
7,300
7,100
2,100
700
12,000
11,400
7,600
14,700
10,200
16,800
10,700
1,500
5,500
9,600
2,200
3,200
11,200
160
17,200
7,400
10,600
11,400
1,010
530
9,600
1,500
4,200
11,300
7,400
49,500
890
1,600
5,300
2,300
120
10,700
81
333,191
Gold
40
3,500
490
-
54,200
6,900
--
--
-
--
8,600
--
•-
--
--
--
9
.-
--
1
--
--
2,300
.-
2,300
--
--
16
2
890
--
--
2,500
1
81
240
160
--
2
82,232
Phosphate
Rock Iron Ore
21,300
.
.-
40
360
10
._
40
58,100
40
1,300 14
-
-
2
-
--
20
40
H
450
890
27,400
12
81
40 4
-
240
_-
400
40
280
120 40
-
1,600
_-
4
3,600
--
3,300 40
10,900 2,100
3,900
4 202
--
40 3,100
8
40
20
320 121
74,124 66,446
All Other
607
8,200
3,300
3,400
4,600
40
4
1,100
4,900
4
1,700
-
160
930
81
202
690
320
360
490
650
3,400
2,500
-
7,900
80
730
1,900
240
1,600
810
240
570
570
160
650
1,300
5,600
1,130
810
160
1,700
-
-
1,700
65,488
Total
54,247
4,010
13,090
9,140
70,368
22,240
6,580
2,305
76,300
8,800
4
16,594
57,880
50,700
17,962
24,131
51,672
12,420
14,099
10,198
16,280
14,920
46,691
11,972
23,981
10,955
11,660
13,330
3,320
13,710
2,651
23,472
14,754
14,950
111,970
11,080
3,765
149,841
1,508
13,251
13,770
40,790
67,430
2,227
2,690
24,630
3,238
79,080
14,362
4,167
1,289,765
189
-------
A part of the area in Table 5-6 is that associated with
active surface mining sites as well as inactive sites.' The U.S. Depart-
ment of the Interior study has subdivided the surface mining areas into
land that does or does not require reclamation. Of the 1.29 million
hectares of disturbed land, reclamation is needed for 830,000 hectares,
while 460,000 hectares do not require reclamation.
(b) Current statistics on active mining operations: The
pollution potential from current mining activities can be qualitatively
estimated by considering specific factors of the mining industries.
These factors include: the type of mineral being mined, the tonnage
of mineral extracted, the type of mining method, and the location of
the mining activity.
The U.S. Bureau of Mines annually publishes The Minerals
Yearbook..5ft/ This volume is an extensive compilation of current data
pertaining to mining activities. Data of interest to persons concerned
with pollution from mining include:
1. Material handled at surface and underground mines,
by commodity.
2. Material handled at surface and underground mines,
by state.
3. Percent of crude ore and total material handled at
surface and underground mines, by commodities.
4. Percent of crude ore and total material handled at
surface and underground mines, by states.
5. Number of mines, by commodity and crude ore production.
6. Kind of surface mining operations, by commodities
and states.
7. Mineral production in the United States, by commodity.
8. Mineral production in the United States, by states.
9. Minerals produced in the United States and princi-
pal producing states.
In many cases, the current data can be used to deter-
mine trends in mineral production by comparison with corresponding
data for preceding years. These comparative data are helpful in assess-
ing the magnitude of active mining operations.
190
-------
For the specific case of coal, the National Coal Associa-
tion annually publishes Bituminous Coal Facts.-L^/ This report contains
extensive data on current coal production as well as historical data
for the past 50 years.
5.2.6 Pollution from modern mining operations; As implied
throughout this discussion, it is unrealistic to assume that pollu-
tion from mining activities can be completely eliminated. However,
it is realistic to expect that pollution can be markedly reduced.
(a) Mined land reclamation: Land reclaimed from min-
ing operations remains a potential source of pollution, even though
the reclaimed land may be used for other activities such as agri-
culture, silviculture, or recreation. Materials potentially capable of
creating pollution are still present in the area, and indiscriminate
use of the reclaimed land may undo the reclamation operation. It has
been noted in some cases that the premature plowing of reclaimed land
has exposed buried toxic material. This exposure resulted in plant
toxicity, together with renewed acid and sediment production. Thus,
time is required to reestablish an equilibrium in the environment.
The reclamation of land usually requires extensive use
of fertilizers to create soil conditions such that vegetation can
prosper. In some cases, limestone may be necessary to reduce acid
generating potential in reclaimed land, and irrigation may be necessary
to provide sufficient water for rapid vegetation cover. In most
reclamation operations, the principal objective is to establish adequate
vegetation cover in order to minimize sediment transport to local
streams and reservoirs. Thus, some pollution from reclaimed mined
lands will be the same as that encountered in agricultural operations.
Reclamation of mined land can greatly alleviate the
pollution problems associated with mining. For the specific case
of surface mining for coal, the environmental consequences of the min-
ing operation have been estimated and compared with the effects result-
ing from mined land reclamation operations.—' These effects are
presented in Table 5-7. The ratings in the table have been divided into
two categories: (1) effects of surface mining operations, and (2)
effects of the reclamation operation. A plus (+) rating means that a
specific adverse environmental effect is aggravated; a negative (-)
rating implies that the adverse effect can be corrected. It is clear
that the mining operation per se creates tremendous damage to the
191
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environment. However, the environment can generally be restored to
usefulness with the application of good reclamation procedures. In-
deed, two environmental components (flood control and adjacent land
use) can be improved as a result of the mining operation.
It is clear, from Table 5-7, that active mining opera-
tions degrade all environmental components, but that these environmental
components can often be restored by the reclamation operations. How-
ever, much of the pollution generated during the mining operation will
have been dispersed before reclamation activities can begin. Thus,
the real importance of reclamation operations is to prevent additional
pollutants from being generated after mining has ceased.
Modern coal mining techniques have the potential of
integrating mining and reclamation into a single system, in which the
interval between the two operations is minimized--and pollutants emis-
sions are likewise minimized.
(b) Future nonpolluting mining operations: The basic
cause for pollution from mining activities in the country today stems
from the fact that mineral resources have in the past been exploited
without regard to environmental consequences. Compatibility between
mining practices and environmental protection is probably best achieved
by new and improved mining methods which do not create conditions which
lead to pollution. Many such methods are being developed today.
New methods for the surface mining for coal have been
detailed in a report by the Council on Environmental Quality to the
U.S. Senate Committee on Interior and Insular Affairs.ID/ This re-
port contains an environmental and economic assessment of alternatives
for coal surface mining and reclamation. Presented in the CEQ report
is a table estimating the environmental effects of coal surface mining.
This table is reproduced here as Table 5-8.
The ratings in this table are subjective. They are,
nevertheless, realistic, and show clearly that surface mining integrated
with reclamation can result in only minor environmental damage.
Future mining operations will be based upon the mining
of the sea bottom to recover minerals. The extraction of minerals from
the ocean floor has unknown pollution potential. It is known from land
mining that any disturbance will affect the local ecology. Adverse
effects on the marine ecology caused by ocean-floor mining are much
less clearly understood than those associated with land-based mining.
193
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It is important to recognize now that this problem exists, and that
ocean mining methods be developed so that pollution from these opera-
tions can be eliminated, or at least minimized.
Similarly, the need for energy sources may lead to use
of the oil shale resources in the Rocky Mountain area. Nonpolluting
mining techniques should be used to recover this resource.
5.3 Data Interpretation Aids and Prediction Methods Pertaining to
Pollution Sources from Mining
5.3.1 Statement of purpose: Most of the available data
pertaining to mining pollution consists of water analyses. The key
to a good predictive model for mining sources lies in relating water
quality data obtained from routine analysis to the source of con-
taminants which may be found in the sample. Concepts for such a model
are presented here.
In general, water quality data are representative of the
kinds of activities which are occurring in a particular watershed.
Physical and chemical data reflect fundamental laws of physics and
chemistry, and data must be explainable in terms of these laws. For
the case of mine drainage, a check of anion-cation balance is very
useful: positive ionic charge (cations) from hydronium and metallic
ions must be equal to negative ionic charge (anions) from sulfate and
bicarbonate ions. The utility of anion-cation balance is discussed in
the 13th Edition of Standard Methods for the Examination of Water and
Wastewater, pp. 38-39.-=.' Variance from equality is significant, and
means that other materials are in solution and have not been detected
by the analysis. Nomograms using this relationship have been developed
and are presented. Methods for translating raw data to a form where
the anion-cation balance can be checked are also presented.
It is recognized that most planners and engineers have
limited resources to obtain the information which is desired for
coping with pollution problems. Therefore, it is essential that re-
sources be used in the best possible manner to yield as much information
as possible. This evaluation of mining pollution represents an initial
effort to give planners and engineers tools with which more informa-
tion can be gleaned from existing data and data gathered in the future.
195
-------
5.3.2 Empirical aids for interpreting water quality data:
(a) Nomograms for mine drainage data interpretation:
The chemistry of formation of mine drainage and of its reactions with
materials in the watershed must yield an electrically neutral system
in which positive charge (cations) is balanced with negative charge
(anions). Two simple nomograms, Figures 5-1 and 5-2, have been de-
veloped which can be used to determine how close the balance is from
analytical data obtained from water samples. The nomograms have been
developed using several hundred data for mine drainage in Appalachia.—
However, the principles on which they are based are universal, and the
nomograms are applicable to any mine drainage containing sulfate and
acidity plus associated neutralization products (hardness). The choice
of nomogram depends upon the pH of a particular sample and the method
of hardness determination.
Both nomograms assume that the principal source of nega-
tive charge is sulfate anion, and the principal sources of positive
charges are hardness and hydronium (acid) cations. The two nomograms
are based upon the rule of thumb that sulfate is equal to net acidity
plus hardness. Net acidity is the difference between measured acidity
and measured alkalinity (see Section 5.3.3). Hardness generally con-
sists of calcium and magnesium cations. In the case of mine drainage,
iron, manganese, and aluminum can also contribute to hardness.—' The
general equation is thus;
Sulfate (in milligrams per liter CaCOg) = Net acidity (in milligrams
per liter CaCC^) + Hardness (in milligrams per liter CaCOs)
The conversion of milligrams per liter of sulfate as 804
to milligrams per liter of sulfate as CaCC>3 has been built into the
nomograms. Thus, the usual sulfate reporting units (milligrams per
liter as SO^) can be compared directly with the usual hardness and
net acidity units (milligrams per liter as CaCOs).
The two nomograms have been developed to accommodate
differing pH's and differing ways that hardness is determined, and are
used for the following cases;
Nomogram I (Figure 5-1):
a. Sample pH between 8.3 and 5.0; hardness measured by
EDTA titration or soap precipitation.
b. Sample pH below 8.3; hardness calculated from calcium
and magnesium concentrations.
196
-------
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a. pH Between 8.3 & 5.0, Hardness Measured
by EDTA or Soap
b. pH Below 8.3, Hardness Calculated
" from Calcium & Magnesium 5000 J
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Figure 5-1
197
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pH Below 5.0, Hardness Measured
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Figure 5-2
198
-------
Nomogram II (Figure 5-2):
Sample pH below 5.0; hardness determined by EDTA titra-
tion or soap precipitation.
Selection of the proper nomogram is determined by sam-
ple pH and by the procedures used to determine hardness. The pH range
of Nomogram I is limited to 5.0 to 8.3, since acidic cations (iron,
manganese, and aluminum) are usually not present in large quantities in
this pH range. At lower pH's, these metals are usually present in sub-
stantial quantities and report as hardness, causing an overestimation
of cations. Discussion of how overestimation can arise is presented
in Section 5.3.3. In Nomogram II, the acid metals (converted to calcium
carbonate values) are subtracted from the sum of acidity and hardness.
The two nomograms each consist of three vertical lines.
The left line (Line A) represents sulfate values reported in milli-
grams per liter SO^. Two sets of indices are shown on Line A, one
ranging from 0 to 500 mg/liter, and the other ranging from 0 to 5,000 mg/
liter. The 0 to 500 mg/liter index (outside of Line A) has been arbi-
trarily divided into three categories: 0 to 50 mg/liter, representing
a "minor" contribution of mine drainage; 50 to 250 mg/liter, represent-
ing a "moderate" mine drainage problem; and 250 to 500 mg/liter represent-
ing "significant" mine drainage. The 0 to 5,000 mg/liter index on the
inside of the sulfate line is indicative of serious mine drainage prob-
lems.
The right line (Line B) on each nomogram represents the
"cations" present in the sample as reported in milligrams per liter
CaC03. As stated earlier, the value for Line B is the sum of net acidity
plus hardness for Nomogram I, and net acidity plus hardness minus acid
metals (iron, manganese, and aluminum) for Nomogram II. Line B also
has two sets of indices to permit nomogram utilization over a range of
concentrations. The outside index ranges from 0 to 500 mg/liter CaC03,
and the inside ranges from 0 to 5,000 mg/liter.
Line C is used as a measure of how well sulfate anion
balances with acid-hardness cations. A tie line connecting a sulfate
value on Line A with an acidity-hardness value on Line B will intersect
Line C at the zero point, if ionic charge balance is present in the
data. The zero point on Line C is the solution to the equation:
Sulfate - (Net Acidity + Hardness) = 0
199
-------
Line C is divided into three ranges. The NORMAL range
represents reasonable chemical balance between sulfate and acidity-
hardness. If the amount of sulfate is significantly greater than the
amount of acidity-hardness, then a POSITIVE VARIANCE is indicated.
If sulfate is less than acidity-hardness, then the nomogram will indi-
cate NEGATIVE VARIANCE.
When comparing sulfate with acidity-hardness, the out-
side sulfate index on Line A is measured against the outisde acid-
hardness index on Line B, and vice versa. If an outside index is
measured against an inside index, then erroneous intersections with the
Line C will result.
The use of the nomogram involves the following steps:
1. The proper point on Line A is located by using the
sulfate concentration found in the sample.
2. The proper point on Line B is located by determin-
ing the sum of net acidity (acidity less alkalinity) and hardness.
This sum is used directly for Nomogram I; it is corrected for acid
metals (reported as CaC03) in Nomogram II. To obtain the acid equivalents
in milligrams per liter CaC03 for the acid metals, the following con-
version factors are used.
Metal Conversion Factor
Aluminum Milligrams per liter CaC03 = 5.56 mg/liter Al
Iron Milligrams per liter CaC03 =1.79 mg/liter Fe
Manganese Milligrams per liter CaC03 = 1.82 mg/liter Mn
3. After the appropriate points on Lines A and B have
been chosen, a tie line is drawn between them. The intersection of the
tie line with the Line C shows how closely the anions in the system
balance with the cations. If a balance is achieved, then the inter-
section is above the normal range, a POSITIVE VARIANCE is noted indi-
cating an excess of negative charge or a deficiency of positive charge.
If the intersection is below normal, NEGATIVE VARIANCE exists, which
signifies excess positive charge or deficient negative charge. If
either positive or negative variance is found, the analytical informa-
tion is incomplete with respect to cations of anions, or both.
The following discussion is presented to show what
positive and negative variances signify.
200
-------
Positive Variance
1. Cation deficiency or sulfate excess.
2. Alkali metals (sodium and potassium) may be present.
3. If drainage has passed through feldspar or mica-
containing soils or strata, presence of potassium is likely.
4. Mine drainage has been neutralized by sodium
alkalinity, i.e., soda ash or sodium bicarbonate.
5. The sample contains sodium sulfate from an industrial
waste discharge.
6. If Nomogram I is used and hardness is determined by
atomic absorption values for calcium and magnesium, other metals con-
tributing to hardness, e.g., zinc, may be present.
7. If Nomogram II is used, the contribution to the
acidity by iron, manganese, and zinc may be overestimated; the correc-
tion factor for acid metals may thus be too high, resulting in a cation
deficiency.
Negative Variance
1. Sulfate deficiency or cation excess.
2. Chloride or nitrate may be present, arising from
industrial discharges of calcium chloride or nitrate.
3. If the sample is taken in winter, calcium chloride
may be due to use of deicing salt on roadways.
4. If ferrous iron or manganese is present in the sam-
ple, they can be partially oxidized resulting in abnormally high acidity
values.
5. If Nomogram I is used and hardness measured by EDTA
titration or soap precipitation, small amounts of ferric iron and
aluminum would contribute to hardness as well as acidity, resulting in
a cation excess.
201
-------
The fact that an intersection between sulfate and
acidity-hardness falls in the NORMAL range does not necessarily indi-
cate that the analysis is complete; it merely means that the contribu-
tion of mine drainage has been accounted for. For example, if the
water sample contains sodium chloride, the nomogram would not so indi-
cate. Thus, the nomograms must be used with judgment, realizing that
they do not necessarily yield a total description of samples.
Since either positive or negative variance indicates
incomplete or inaccurate analytical data, the nomograms can provide
information pertaining to what data are missing, and can be used to
indicate where the missing data may be found; i.e., does one look for
chloride or potassium? Whether the analyst would look further for the
missing data is a matter of judgment and policy.
(b) Aids for converting raw data into useful form: Raw
analytical data are normally reported as a concentration of a particular
substance in parts per million (ppm) or milligrams per liter (mg/liter).
Since a liter of water weighs 1,000 g or 1 million milligram, parts
per million and milligrams per liter are equivalent.
ppm = mg/liter
If data are to be used to check the anion-cation balance
then concentration data in milligrams per liter must be converted into
milliequivalents per liter (meq/liter).
Milliequivalents per liter are often arbitrarily ex-
pressed as milligrams of CaC03 per liter (mg/liter CaCC>3) . The term
milligrams per liter CaCO^ is convenient since most analyses for the
general parameter of "hardness" are reported as such. Alkalinity and
acidity, also related to hardness, are generally reported as milligrams
per liter CaCOo. The use of calcium carbonate equivalents is also con-
venient because the equivalent weight of CaCO^ is 50 mg/meq.
mg/liter CaC03 = 50 x meq/liter
A table showing conversion factors for common cations
and anions to either milliequivalents per liter or milligrams per liter
CaC03 is presented in Table 5-9. This table can be used to convert
concentration to the form of either milliequivalents per liter or milli-
grams per liter CaC03. By adding up the milliequivalents per liter of
cations and comparing to the similar sum of anions, it is possible to
assess the completeness of analytical data, and to judge which data may
202
-------
TABLE 5-9
FACTORS FOR CONVERTING CONCENTRATION DATA INTO FORMS FOR CHECKING ANION-CATION BALANCE
meq/ liter =
Cation mg/liter times:
Aluminum,
A1+++
Ammonium,
NH4+
Barium,
Ba-H-
Calcium,
Ca-H-
Copper,
Cu++
Iron:
Ferrous,
Fe++
Ferric,
Fe+++
Hydrogen,
H+
Lead,
Pb++
Potassium,
K+
Lithium,
Li+
Magnesium,
Mg++
Manganous ,
Mn++
Sodium,
Na+
Strontium,
Sr++
Zinc,
Zn++
0.111
0.0554
0.0146
0.0499
0.0315
0.0358
0.0537
0.992
0.00965
0.0256
0.144
0.0823
0.0364
0.0435
0.0228
0.0306
mg/liter as
CaCOa =
mg/liter times:
5.56
2.77
0.729
2.50
1.58
1.79
2.69
49.6
0.483
1.28
7.21
4.12
1.82
2.18
1.14
1.53
Anion
Borate
B02~
Bromide,
Br~
Chloride,
Cl"
Carbonate,
co3=
Bicarbonate,
HC03"
Fluoride,
F"
Hydroxide,
OH-
lodide,
I"
Nitrate,
N03-
Nitrite,
N02"
Phosphate,
P04 =
Monohydrogen
Phosphate,
HP04=
Dihydrogen
Phosphate,
H2P04-
Sulfate,
so4=
Sulfide,
S=
Bisulfide,
HS-
meq/ liter =
mg/liter times:
0.0234
0.0125
0.0282
0.0333
0.0164
0.0526
0.0588
0.00788
0.0161
0.0217
0.0316
0.0208
0.0103
0.0208
0.0624
0.0302
mg/liter as
CaC03 ---
mg/liter times:
1.17
0.626
1.41
1.67
0.820
2.63
2.94
0.394
0.807
1.09
1.58
1.04
0.516
1.04
3.12
1.51
203
-------
be missing if equality is not achieved. The nomograms described earlier
have been developed using this concept.
Other aids to water quality data interpretation using
this concept are discussed in Hem's treatise entitled Study and Inter-
pretation of the Chemical Characteristics of Natural Waters.33/ This
treatise details several simple graphical methods which pictorially
represent water quality. Use of these methods require more complete
analyses than are generally available for describing pollution from
mining operations. It is likely that these methods may be useful in
the future when more complete sets of data are available.
The Hem models are applicable to pollution sources in-
volving salinity. The unknown extent of salt pollution from gas and
oil well drainage should be readily ascertained using these models.
The models have been useful in tracing salt water intrusion into fresh
water supplies in coastal areas.
Hem's descriptions of the several models are good sources
of information about possible ways and means of presenting analytical
data in a simple and useful form. A careful study of the document may
assist the planner or engineer in developing ways to manipulate data
into a more readily understandable or useful form.
The U.S. Geological Survey has published a report entitled
The National Hydrologic Bench-Mark Network.2/ This report describes
stations designated to provide data on stream basins which have not been
seriously affected by man's activities, and reports data in a straight-
forward manner. Thus, data obtained from these stream basins are not
influenced to a great degree by the environmental alterations caused
by population growth and changing land use patterns.
There are 57 bench-mark basins in 37 states. These
basins are in areas having a wide variety of climate and topography.
Data acquired from these stations can be used to estimate background
concentrations of specific indicators of pollution. By comparing
data obtained on a stream known to be affected by man with data acquired
from a bench-mark stream having similar characteristics of climate,
geology, and topography, it should be possible to gain insight on the
nature and extent of pollution in the watershed under consideration.
(c) Trends observed from mine drainage data; Data con-
cerning stream quality in Appalachia are abundant.5,28,44/ These data
have been plotted against one another to determine trends which exist that
204
-------
could be the basis for additional tools for data interpretation. The
plots are summarized below.
(A) (B) Net
Number of Plots Number of Plots Correlatability
Plot Correlating Not Correlating (A)-(B)
Metals and Dissolved
Solids vs Stream
Flow 6 5+1
Number of Sources vs
Acid 12 9 +3
Drainage Area vs Acid 0 8-8
Sulfate vs Acid 10 3 +7
Stream Mile vs Acid 1 3-2
This simple approach shows that certain variables are
correlatable and thus potentially translatable into prediction tools.
The greatest number of correlations was found with sulfate and acid,
the system on which the nomograms described earlier are based.
The next greatest number of correlations is found in the
plots of number of drainage sources versus acid in the stream. This
correlation is worth developing further. Factors which affect this
correlation are: tonnage of product mined (past and present), geographi-
cal location, soil type, geology, topography, and climate.
Plots which were noncorrelating include drainage area
versus acid, and stream mile versus acid. These plots indicate that
the size of the drainage area is not as important as the number of
sources in the area, and that pollution from mining is more likely
to arise from springs, abandoned mine shafts, leaching gob piles,
etc., than from the general region in which mining occurs.
Definitive relationships for metals and dissolved solids
versus stream flow were not uncovered.
The relationships of stream data to mining sources and
to geologic and hydrologic conditions that may result in pollution are
real. The trends discussed here are capable of being reduced to simple
prediction tools, in a logical next step in the continuing effort to
describe more fully and completely the nature and extent of pollution
from mining operations.
205
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5.3.3 Discussion of sampling and analytical methods; This
section discusses sampling procedures and analtyical methods for mining-
related wastewaters.
(a) Sampling techniques and procedures; The acquisition
of a truly representative sample is of great importance, if the data
obtained from the sample are to be of use to the planner or engineer.
Hem's treatise on the Study and Interpretation of the Chemical Char-
acteristics of Natural Waterjj./ presents in great detail the problems
associated with obtaining a representative sample. The heart of the
problem lies in the fact that a body of water is not homogeneous,
particularly if the water is moving. For example, Hem presents analyses
of the Susquehanna River water taken at Harrisburg, Pennsylvania, in
which east bank samples are acid (pH = 5.2) and west bank samples are
alkaline (pH = 7.4). Concentrations of hardness and sulfate also vary
widely. Thus, the question is raised: What does an average analysis
of Susquehanna River water at Harrisburg really mean? Knowledge of
the nature and extent of sources contributing to the analytical data
is necessary to answer the question.
Water quality data can be no better than the quality of
the sample from which the data are obtained. In recent years, automatic
samplers and analyzers have been installed as a means of gathering a
large number of data per man-hour of effort. However, the automatic
devices have the shortcoming of not being able to judge whether a sam-
ple is good or bad. As a result, some data obtained by automatic
methods may be subject to question. For example, if a sample is taken,
and some sediment passes through the filtering device into the analyzer,
the data reported by the analyzer will not truly reflect the composition
of the aqueous plane.
Another important aspect of sampling and analysis is the
time lag between sample acquisition and sample analysis. This time lag
is of considerable importance in mine drainage samples because reactions
will continue after the sample has been taken. For example, if the
water sample contains iron sulfate, the ratio of ferrous to ferric iron,
an important indicator of mine drainage, will change. If the sample con-
tains aluminum ion, sample aging may permit hydrolysis of aluminum into
aluminum hydroxide, and suspended solids (sediment) would then be over-
estimated and aluminum underestimated.
Time lag is of concern when automatic samplers are used
without automatic analyzers. An automatic sampler collects a series
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of samples and holds them until they are retrieved for analysis. The
frequency of sample retrieval can vary from several hours to several
weeks. Thus, the samples taken at the beginning of the cycle have
aged longer than those taken at the end. Analytical data obtained from
the samples can reflect the aging process, and should be interpreted
with sample age in mind.
The U.S. Geological Survey, Office of Water Data Coordina-
tion, has recently published a preliminary report concerning Recommended
Methods for Water-Data Acquisition.^:/ This report contains valuable
information pertaining to all aspects of sampling and analysis, includ-
ing procedures for acquiring, preserving, and analyzing samples. Tech-
niques are described in detail relating to the following subjects;
Surface water
Groundwater
Fluvial sediment
Biologic, bacteriologic, and chemical (organic) quality
of water
Chemical (inorganic) and physical quality of water
Automatic water quality monitors.
The information in this handbook is of great assistance
to planners and engineers who deal with water quality problems.
(b) Analyses usually performed: Analyses for mine
drainage usually consist of all or some of the following: acidity,
alkalinity, sulfate, hardness, iron, manganese, and aluminum. Cations
are reported as acidity, hardness, iron, manganese, and aluminum;
anions as sulfate and alkalinity. In general, all metal cations will
report as hardness except the alkali metals, i.e., sodium, potassium,
and .ammonium. Anions which may be found in significant amounts in
surface waters include chloride and nitrate.
Metallic cations; Cations can be measured by
several methods. One method is atomic absorption spectroscopy, which
yields precise information for specific metals sought. This method
involves sophisticated instrumentation usually not available to field
water quality laboratories. The atomic absorption method is most use-
ful for determining traces of metals present in the sample.
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For common metal ions in water samples, wet chemi-
cal techniques can be employed. Those techniques can be used to deter-
mine most metals with exception of the alkalis, sodium and potassium.
Wet chemical techniques used to measure "total hardness" will give re-
sults which include the common heavy metals as well as calcium and
magnesium, the usual components of hardness. "LI The two common tech-
niques for determining total hardness are (1) titrating the sample
with EDTA (ethylenediamine tetraacetic acid) and (2) precipitation of
metal stearates with soap. If calcium and magnesium need to be re-
ported separately, then any heavy metal contribution to the total
hardness must be subtracted.
Individual concentrations of metallic cations (ex-
cluding alkaline earth and alkali metals) can often be estimated using
colorimetric methods. Standard methods are available for laboratory
o o o o /
analysis} » '^ ' as well as field kits for on-site analysis. These
field kits are available from several suppliers. Use of these methods
will yield information pertaining to heavy metals which may be present
in the sample.
Acidity; Acidity measurements are conducted by
titrating the sample with standard sodium hydroxide to a prechosen pH
value. The final pH of most acidity determinations is 8.3, the point
where phenolphthalein indicator changes color. However, in recent
years, the pH of 7.0 has been suggested as an end point, since it
represents exact theoretical neutralization in aqueous systems. Since
most data have been obtained by titrating to pH of 8.3, they may re-
flect an overestimation of acidity.
Acidity can also be more accurately determined if
metals which are potentially oxidizable in the titration with standard
base are taken into consideration. The most common ones found in mine
drainage are ferrous iron and manganese. The reactions are:
2Fe++ + 40H" + 1/2 02 + H20 } 2Fe(OH)q
Mn++ + 20H- + 1/2 02 > Mn02 + H20
These two reactions will consume base and hence report as acid, even
though the consumption of base arises from neutral salts, e.g., ferrous
or manganous sulfates. Thus, if ferrous iron or manganese is present
in the sample, one should be aware of the possibility that the measured
acidity may be high.
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One method of ensuring that acidity measurements
do include acid potentially present from ferrous iron and manganese
is to oxidize the sample with hydrogen peroxide prior to the acidity
determination._t2/ This oxidation will convert all ferrous iron into
ferric iron, and the manganese into manganese dioxide.
Fe++ + 1/2 H202 + 2H20 > Fe(OID3 + 2H+
Mn++ + H202 > MnOo + 2HT1"
By measuring the ferrous iron and manganese contents in the original
sample, it is possible to correct the acidity for that generated in
hydrogen peroxide treatment of ferrous iron and manganese.
This procedure should yield more accurate acidity
measurements, since air oxidation of the iron and manganese can vary
widely depending upon the nature of the sample and the analyst's tech-
nique.
Ferric iron or aluminum in solution will also con-
sume hydroxide. Since these cations are in their highest oxidative
stata, they will report as acid without the need for hydrogen peroxide
treatment.
30H~ 3> Fe(OH)3
30H- > A1(OH)3
Sulfate: Analysis for anions includes sulfate
and alkalinity determinations. Sulfate analyses are generally simple
and reliable. The techniques include the precipitation and weighing
of barium sulfate, light scattering by finely divided barium sulfate,
and titrating with barium chloride using thorin indicator. The EPA
method,JL?./ which involves titration with barium chloranilate, is not
generally satisfactory for mine drainage since cations (calcium, aluminum,
and iron) present in the sample will interfere with the sulfate deter-
mination unless special pretreatment measures are taken.
Alkalinity: Alkalinity is determined by titrating
the sample with standard acid to pH of 4.5. Mine drainage samples
having pH's greater than 4.5 may thus contain alkalinity as well as
acidity. Traditionally, alkalinity has been associated with the bi-
carbonate-carbonic acid, and carbonate-bicarbonate equilibria in waters.
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At pH's above 8.3, water contains carbonate and bicarbonate in equi-
librium; below pH of 8.3, waters contain bicarbonate and carbonic acid
in equilibrium. Since the pH of mine drainage is usually less than 8.3,
one is concerned with the bicarbonate-carbonic acid equilibrium.
Bicarbonate arises in mine drainage through the
dissolution of limestone by acid. If the drainage passes through a
limestone-abundant formation (as it usually does for those drainage
samples having a pH above 4.5), then bicarbonate will be present and
contribute anions to the system.
Net acidity: The preceding discussion dealt with
alkalinity and acidity, and how analyses can result in inconsistencies
and misinterpretation. A convenient way around the complexities of
the chemistry involved in interpreting acid and alkalinity data are
through the use of "net acidity." Net acidity is the difference between
measured acidity and measured alkalinity. Net acidity can be either
positive or negative. If it is positive, then acid (or acid forming
salts) are present in the system. If it is negative, the bicarbonate
can be considered a genuine species in the system.
(c) Analyses not usually performed; It is impractical
in routine analyses to determine every element which could be present
in a given sample. However, analysis for anionic species, particularly
chloride and nitrate, would help to complete the picture of a given
sample. Standard field kits are available for determining chloride
and nitrate.
Chloride and nitrate: Chloride and nitrate are
generally present in most natural waters. Therefore, they will normally
be present in mine drainage, though to a smaller extent than sulfate.
The cation component of the chloride and nitrate salts is usually alkali
or alkaline earth metal. If it is alkaline earth, then it will be re-
ported as hardness.
If substantial quantities of chloride or nitrate
are found in waters known to be contaminated with mine drainage, then
one must suspect that they are arising from sources other than mining.
Sources may be industrial discharges of lime-treated hydrochloric or
nitric acids. These discharges would add calcium chloride or calcium
nitrate to the water. In wintertime, calcium chloride deicer can be
flushed into the watercourse. Other sources would also include salt
210
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springs, perhaps from abandoned oil/gas wells in the areas, which
would add chloride. Runoff from agricultural land can be a source of
nitrate.
Alkali metals; Missing cations, on the other hand,
are probably mainly sodium and potassium. If these ions are present
in quantities greater than that expected in the background, they can
be considered to be pollutants. A likely source of sodium is from
oil/gas wells which may drain into the watershed.
Potassium, on the other hand, can arise as a con-
sequence of mine drainage. As has been pointed out in Section 5.2.2,
alkali oxide contents of clays will neutralize acid and dissolve
aluminum. If feldspathic and illitic (mica-containing) clays are in
the watershed, mine drainage can be expected to contain potassium.
This source of potassium will be present even if
the aluminum concentration in the sample is low. Aluminum solubilized
from clays and neutralized by limestone can be removed. Once potassium
has been dissolved, it will stay in solution. Thus, knowledge of
geology, both rock composition and soil horizons, can be used to pre-
dict whether potassium is a reasonable constituent of surface or ground-
waters.
Alkali metals are easily determined by flame photom-
etry or atomic absorption spectroscopy. However, these tools are not
always available in field or small local laboratories. Their presence
can often be deduced from knowledge of other chemical analyses, includ-
ing knowledge of the geology of the area being studied.
Heavy metals: Heavy metals may also be missed,
particularly if atomic absorption is used as the single tool for heavy
metal determinations. In preceding discussion, it has been shown
that most heavy metals will report as hardness if determinations are
made using EDTA titration or soap precipitation.
In hard rock mining areas where metal ores are
mined, one should be especially concerned with the possibility of heavy
metals. As discussed in Section 5.2.4, drainage from hard rock mining
areas consistently contains copper,zinc, arsenic, and lead in addition
to the usual iron, manganese and aluminum.
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5.3.4 Models for predicting pollution quantities; Several
studies have undertaken to develop models which would predict pollu-
tion. This section contains brief descriptions of the important models
for predicting mine drainage and sediment.
(a) Models for predicting mine drainage: Various models
have been developed which can be used as predictive tools for mine
drainage and leachate from refuse and spoil piles. The most complete
model has been developed around pyritic oxidation and should be applicable
to both coal and hard rock mining areas containing associated waste
pyritic materials.
The Ohio State University Research Foundation, with EPA
support, has developed a model for predicting pyrite oxidation from
coal mines. Their report, entitled Pyritic Systems: A Mathematical
Model, discusses in detail the pyrite oxidation mechanisms.—' Data
obtained from an experimental mine in Ohio were used to develop a com-
puter program which would predict the flow and chemical characteristics
of the mine drainage. The program was tested on auger holes at a site
other than the experimental mine (but within the same coal seam). Actual
drainage data from the auger holes correlated very well with that pre-
dicted by the computer program.
The program was developed using very general principles
associated with the oxidation of any pyritic system. These principles
should apply to both coal and hard rock mining. Factors affecting the
volume and composition of mine drainage include water tables, seasonal
variation, rainfall amounts, local hydrology, etc. Thus, the computer
program should be able to predict the quantity and quality of mine
drainage, particularly that associated with active and abandoned min-
ing operations in Ohio.
The applicability of the simulation program will be
less precise for Appalachian coal mining areas outside of Ohio, and
even less so for the hard rock mining areas of the West. Nevertheless,
the simulation offers a means of evaluating, in a preliminary sense, the
pollution potential of pyritic systems in various regions.
While the pyritic systems model involves computers and
a lengthy computer program, the model is a valuable information tool
for persons dealing with mine drainage.
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(b) Limestone requirements for pyritic spoils and
overburden: A very useful tool for predicting pollution potential
from mining activities has been developed at the University of West
Virginia.ZP.' This study involves the prediction of acid mine drainage
from spoil banks and coal overburden materials based upon sulfur con-
tent of materials. Detailed descriptions of how sulfur content (acid
forming potential) of spoil and overburden materials is translated
into limestone requirements for controlling acid formations^' were
presented at the First Symposium on Mined-Land Reclamation, Pittsburgh,
Pennsylvania, March 7 and 8, 1973. Reprints of the symposium proced-
ings are available from Bituminous Coal Research, Inc., 350 Hochberg
Road, Monroeville, Pennsulvania 15146.
The equation for acid generation from West Virginia
spoil is ;.==./
Acid generated in milliequivalents acid/100 g sample =
4.93 + 52.29 X (percent pyritic and organic sulfur in spoil);
R2 = 0.970
The samples must be pretreated to remove sulfate and carbonate prior to
determining pyritic and organic sulfur. Spoil samples vary from over-
burden and undisturbed rock samples in that some acid-producing sulfur
in spoil has been oxidized to sulfate. Hence sulfate must be removed
in order to predict potential acidity.
Equations for predicting acid forming potential in West
Virginia rocks and overburden have been established—' as a function
of rock type. This potential exists in nonmined areas, and can be
used as a means of estimating acid formation when and if mining opera-
tions commence. The equations are;
Rock Type Equation
Acid potential (milliequivalents
of acid/100 g sample) =
Sandstone -0.641 + 37.6(%S) R2 = 0.728
Shale -4.40 + 43.6(%S) R2 = 0.864
Sandstone and
Shale -2.54 + 42.4(70S) R2 = 0.862
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Sulfur determinations on the rock samples are made directly, since
sulfate concentrations are generally low. Carbonate contents are
also determined. The negative intercepts of the equations indicate
that the rock does contain small amounts of neutralizing capacity.
While these equations specifically relate to West Virginia,
the principles from which they are developed are universal. Any area
which has a potential acid problem from coal refuse, sulfur-containing
spoil banks, or unmined resources associated with oxidizable sulfur,
can follow the methodology and procedures outlined in the West Virginia
University studies. The procedures will yield equations similar to
those described above for a particular region, and help to provide con-
ditions for at-source control rather than control after mining opera-
tions have begun or have been abandoned.
(c) Infiltration of water into spoil banks; The infiltra-
tion of water in spoil banks has been modeled less successfully, by
Vimmerstedt.£2.' This study involved the use of lysimeters to determine
important parameters in predicting mine drainage. Data generated
from the lysimeters were compared with the empirical equation for in-
filtration:
VQ = 1/2 St~1/2 + A
where V = infiltration rate (dimensions: length x time'l)
S = sorptivity (dimensions; length x ti
t = time
A = permeability at zero capillary potential, and decreases
with decreasing moisture content (dimensions: length x
time'1)
Variations in infiltration rates could not always be accounted for by
the variables: volumetric soil moisture, bulk density, and soil types.
It was found that when the exponent for time (t) was changed from -1/2
to -1, the fit was improved. This observation may indicate that depth
of water penetration into the spoil bank is a more important parameter
than is sorptivity.
(d) Leachate quantities from spoil banks: The prediction
of amounts of pollutant from spoil banks developed by Vimmerstedt and
Struthers as a result of lysimeter studies has been more successful.—'
This study, based upon different spoil types in Ohio, has shown that
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the pollution generated from the spoil is dependent upon type of soil
being leached. The classifications of spoil types are:
Toxic—pH of surface material less than 4.0 on more
than 75% of the area.
Acid--pH from 4.0 to 6.9 over 50% of the surface area.
Marginal--5070 to 75% of the surface area with a pH
below 4.0, the remainder being acid, calcareous, or mixed.
Calcareous--pH above 7.0 or over 5070 of the surface
area.
The general findings of the study were that toxic spoil
yielded the most acid and salts, in quantities nearly 100 times greater
than did soil. Marginal spoils were the next worst polluters followed
by calcareous and acid spoils. In addition, the lysimeter studies
showed that the rate of pollutant leaching was quite rapid (half-life
of 3 to 4 years) for toxic spoils, while the other spoils were leached
at a slower rate (half-life of 6 to 8 years). The conclusion drawn
was that spoil banks have a finite lifetime, and that they would be-
come nonpolluting after an exposure of many years.
However, the lysimeter experiments did not provide for
fresh surface exposure in the spoil during the course of the experi-
ment. Therefore, the validity of this conclusion is somewhat question-
able in the practical sense. Even with a half-life of 3 to 4 years,
the amount of pollutant leached from toxic spoil was 50 times greater
than that from soil.
In terms of pollutant quantities found in the first year,
toxic spoil yielded about 94 metric tons/hectare (42 tons/acre) of
acid and salts, marginal spoil about 22 metric tons/hectare (10 tons/
acre), calcareous spoil about 4.5 metric tons/hectare (2 tons/acre),
acid spoil about 3.4 metric tons/hectare (1.5 tons/acre), and soil
about 1.3 metric tons/hectare (0.6 ton/acre).
(e) Pollution potential from spent oil shale; The
Colorado State University has developed a prediction model for esti-
mating water pollution potential of spent oil shale residues, under
EPA auspices.ir-' This report is of general interest to planners and
engineers since it very carefully details the methodology which must
215
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be used in developing sophisticated models for predicting leachate
and sediment. This methodology was used to develop a computer program.
However, the logic and methodology for analyzing various parameters
is useful in developing rule of thumb tools for predicting nature and
extent of nonpoint pollution.
(f) Prediction of mine drainage volumes in localized
areas: Models to predict mine drainage volumes on a county-wide basis
have been described by Tybout.—' Equations have been developed relat-
ing the annual volumes of mine (underground) drainage to the mine
ceiling area exposed by production over past years. Equations are
presented for both active and underground mines;
Active underground mines:
Metric: Y = 0.00223 X n_i5) + 0.00104 X (16_34)
English: Y = 0.0907 X (i_]_5) + 0.0424 X (!6_34)
R2 = 0.403
Inactive underground mines:
Metric: Y = 0.000504 X n_i5\ + 0.00212 X (16-34)
English: Y = 0.0205 X (1-15) + 0.0865 X . , ,
R2 = 0.847
where Y = thousands of liters (gallons) per year of drainage
in the county (or other mining area).
X (i_i5) = average annual square meters (square feet) of mine
ceiling area exposed by production over the past
15 years in the county (or other mining area).
X (16-34) = average annual square meters (square feet) of mine
ceiling area exposed by production over the 16th
and 34th year in the past in the county (or other
mining area).
216
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Tybout admits that the equations are crude from a statisti-
cal concept. However, he believes that the equations are significant
if used where large numbers of mines are available to reduce the rela-
tive size of the standard error.
Methodology for statistical analysis of existing data is
outlined for different modes of mine drainage sources, i.e., active
underground, abandoned underground, active surface, or abandoned sur-
face. The basis of the analysis is the hypothesis that the rate of
drainage (Y) from mines in a mining area is a linear function of coal
production (X^) in that area over all past years (j).
Y =
The coefficients (aj) of this equation are determined by regression
analyses of drainage and production data extending as far back in time
as possible.
(g) Models for predicting sediment: The second major
nonpoint pollutant from mining operations is sediment. When land has
been disturbed by mining, or when minerals extracted in the mining
operation have been beneficiated, large quantities of waste residue
can be generated. This residue can in some cases wash into streams
causing siltation problems.
Models for predicting sediment loadings have been dis-
cussed in detail in Section 3.0 Agriculture, and Section 4.0 Silvi-
culture. Sediment models specifically directed to mining operations
are discussed here.
Models for sediment control have been developed from
studies of surface mining operations in Appalachia. These models are
good only for this region. In hard rock mining areas in the western
United States, many sediment problems cannot be predicted accurately
because of steep slopes, more abrupt elevation changes, a highly vari-
able rainfall, and lack of soil in mining areas. Nevertheless, the
models developed for Appalachia involve principles which can be used
to develop models for the hard rock areas.
The U.S. Forest Service has developed a model to predict
the outslope of spoil banks generated during coal mining operations in
Appalachia.—' The basic equation is:
217
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Metric: Y = 3.9^ + 0.529X2 - 8.85
English: Y = 3.91X! + 1.734X2 - 29.0
where Y = slope distance covered below outcrop in meters (feet)
Xi = highwall height in meters (feet)
X2 = original slope in degrees
This equation can be used to determine the amount of
disturbed area which can be tolerated in a particular locality by
operating within depth of cut and highwall height limitations. These
limits, established by regulatory agencies or voluntarily met by
operators, can be used to protect property below the mining operation.
Plots of the equation above and below the coal outcrop are presented
as Figures 5-3 and 5-4. A typical cross-section of a contour mine
using the plots is shown in Figure 5-5.
This equation does not take into account the potential
of the downslope cover to slide.
(h) Rules of thumb for estimating sediment loads:
Another study in Appalachia by the U.S. Forest ServicelZ/ has shown
that suspended sediment has increased to the 10,000 to 50,000 mg/liter
range during strip mining operations, compared to a sediment level of
only 150 mg/liter prior to mining. Sediment loads in nonmining areas
ranged from 1,000 to 6,000 m-^/hectare of watershed, compared to 8,000
Q
to 66,000 nrYhectare of watershed in mined areas.
The ranges of these data indicate the wide variability
of sediment problems within single small watersheds, and substantiate
the difficulties associated with predicting sediment loadings from
mining activities. Part of the variation is related to the degree of
reclamation and the age of the reclaimed land.
Other rule of thumb estimates based upon experience with
mining operations in Kentucky are: (1) that the erosion loss from
spoil banks is 790 metric tons/hectare/year (350 tons/acre/year), and
(2) the sediment yield in watercourses is 340 metric tons/hectare/year
(150 tons/acre/year).12'
218
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260
240
g 220
Q.
200
180
O
_o
0)
CO
» 160
u
5 140
ID
CL
O
120
100
80
16 20 24 28 32
Original Slope (degrees)
80
70
60
50
(U
E
a.
o
O
o
0)
o
c
a
AC\ ®
40 a.
_0
00
30
36 40
Figure 5-3 - Predicted Slope Distance Covered with Spoil
Below Outcrop for Various Highwall Heights
(Adapted, Ref. 40)
219
-------
200
180
160
140
o
3 120
O
100
-------
70.5m
-(231Ft.)-
19.8m Pit
-------
While these values do not appear to have been correlated with other
parameters (slope, rainfall, and soil type), they do offer a crude
approximation of what might be expected in the way of erosion and
sedimentation in a watercourse.
(i) Sediment from haul roads; Roads used to carry mined
products from the mining operation to processing operations also are
potential sources of sediment problems. Weigle!^§' has observed that
the degree of erosion from abandoned coal bank roads in Kentucky depends
on soil type. For sandy-silt soil, the erosion rate was 6.6 cm (2.6
in.) of road surface per year. For clayey-silt soil, the rate was
16.7 cm/year (5 in/year). Average width of the abandoned roads was
19.8 m (65 ft), translating to an erosion loss of 1,300 to 2,500 m3 of
sediment per kilometer (1.7 to 3.3 acre-ft/mile) of road annually.
Sediment yield from haul roads can be reduced if the
roads are properly designed and constructed. Weigle has written a
handbook entitled Designing Coal-Haul Roads for Good Drainage.QU
While this pamphlet is written primarily for coal roads in forested
lands, the principles discussed should be applicable to any road as-
sociated with a mining operation, be it coal, hard rock, or other opera-
tions.
5.3.5 Methods for locating pollution sources; Improved
methods of locating mined areas are needed if control procedures
are to be initiated for specific problems. The problem may be more
severe in the less densely populated western United States than in
Appalachia. In the West, many old prospector pits, usually less than
1 acre' of disturbed land, have been abandoned and left unfilled. Most
of these pits have gone unreported unless mineral values worth exploit-
ing were found.
In the coal mining regions of Appalachia, many communities
depend upon mine-drainage-containing waters as sources for industrial
and domestic water supply. Hence, drainage from these mines represents
a serious source of concern to those localities affected. The fact
that abandoned mines cannot be accurately pinpointed and mapped makes
control-at-the-source procedures impossible to apply.
Several studies have been undertaken to determine locations
of abandoned mines through remote sensing. One study, conducted for
the Environmental Protection Agency by HRB-Singer, Inc., State College,
Pennsylvania, involved the evaluation of several geophysical methods
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to locate abandoned underground mines.£_i Among the techniques used
were: airborne infrared radiometry, electrical resistivity, magnetics,
induced polarization, self-potential, very-low frequency electromagnetic
refraction and reflection, and seismic refraction and reflection. Of
these techniques, airborne infrared radiometry proved to be the most
useful. Some correlations existed in the data, but when the techniques
were applied to other areas, they failed to discover "known" abandoned
mines. It was concluded that conventional geophysical methods were
unable to locate abandoned mines. However, with improved sensitivity
devices and a better understanding of the principles of geophysics,
such techniques may be useful in the future.
Disturbed land has been "sensed" by earth satellites and
aerial photography.!^/ This technique is expensive and requires skilled
persons to interpret photographic images. Satellite data are of rela-
tively low resolution (about 80 m), and would fail to detect small
prospector pits such as are found in the West. Aerial photography,
on the other hand, has higher resolution and can locate most sources
of disturbed land. This technique is particularly useful if color
photography is used. However, aerial photography is an art, and use-
ful information must be identified by highly trained persons. In addi-
tion, ultimate identifiers and descriptors of the area must be deter-
mined by ground reconnaissance.
Thus, the most important method of locating abandoned mines
or land disturbed by mining activities, and establishing the nature
and extent of pollution from these sources, is thorough exploration
on the ground. The techniques used in a ground exploration are re-
ported in several Environmental Protection Agency studies. A
typical study has been conducted by the Halliburton Company, Duncan,
Oklahoma,£2/ dealing with a field investigation to locate and define
unknown or hidden drift mine openings in the Browns Creek Watershed
of the West Fork River in West Virginia. This report is a detailed
account of the steps which must be undertaken to locate abandoned
mining operations in a heavily mined area. The process is time con-
suming and expensive, but is necessary if pollutions from abandoned
mining operations is to be controlled.
5.3.6 Information sources pertaining to pollution from
mining: Sources of general water quality information, and sources
of specific water quality information are presented below.
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(a) Sources of general water quality information: The
U.S. Geological Survey, Office of Water Data Coordination, has published
the Catalog of Information on Water Data, a file of information about
water data acquisition activities. Activities reported in this catalog
are listed in three indexes: "Index to Water-Quality Section,"59/
"Index to Surface-Water Section,"^' and "Index to Groundwater Sta-
tions."^./ These indexes describe water data acquisition activities
at specific points in the country, and include the following informa-
tion: who is reporting, what is reported, what is the scope of the
activities, and what are the periods of record.
Entries in the indexes are related to three sets of
maps, one set for each of the three indexes; Water Quality Stations,—'
Surface Water Stations,—' and Groundwater Stations.—' Maps can be
used to pinpoint specific stations, and the index used to determine the
extent of information obtained at the station.
At the present time, the Office of Water Data Coordina-
tion is developing NAWDEX—A System for Improving Accessibility to
Water Data. NAWDEX--National Water Data Exchange—is a concept in
which all water data will be stored in a central system in a form readily
retrievable by computer. Descriptions of the system have been pub-
lished. JLLJi^Lt^LaJil/ The complete NAWDEX system is not yet operational.
When it is, it will be an extremely useful source of water quality data.
At the present time, large quantities of water quality
data are retrievable from STORET, a data bank operated by the Environ-
mental Protection Agency. The EPA's STORET system collects data from
many agencies, and is presently the most comprehensive source of water
quality data. It is in computer-processible form which permits easy
access. Access to the data can be gained through regional EPA offices.
According to the Office of Water Data Coordination, STORET will con-
stitute a major part of NAWDEX in the future.
Bituminous Coal Research, Inc., has published annually
since 1964 a bibliography entitled Mine Drainage Abstracts. These
abstracts are an important information source regarding what has been
published in the area of mine drainage research and in treatment and
control technology. Annual supplements published each year contain
information received that year pertaining to all aspects of mine drain-
age. The bibliography and supplements are available at a nominal cost
from the Library, Bituminous Coal Research, Inc., 350 Hochberg Road,
Monroeville, Pennsylvania 15146.
224
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(b) Sources of specific water quality information; Many
areas of the country have been investigated with regard to specific
pollution problems. Information in these specific studies is generally
available for use to planners and engineers.
The Office of Water Data Coordination of the U.S. Geologi-
cal Survey has compiled a list of such programs in the Index to Areal
Investigations and Miscellaneous Water Data Activities, a. fourth volume
of the Catalog of Information on Water Data.56^7 This index contains
(1) the title of each investigation, (2) the geographic area covered,
(3) the inclusive dates of the investigations, (4) description of the
investigation, (5) whether or not a report will be published, and (6)
the reporting agency. Thirteen federal agencies and 34 state and local
agencies have activities listed in this index.
Regional Environmental Protection Agency offices are a
valuable source of information and assistance to planners and engineers
confronted with special problems concerning mining pollution. These
offices can offer direction and assist in acquiring information from
other branches of the EPA, such as the EPA National Field Investigation
Centers at Denver and Cincinnati, and the Mine Drainage Pollution Con-
trol Section, National Environmental Research Center, Cincinnati.
225
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REFERENCES
1. Agnew, A.F.,and D.M. Corbett, "Hydrology and Chemistry of Coal Mine
Drainage in Indiana," paper presented at 157th National Meeting of
the American Chemical Society, April 13-18, 1969, Minneapolis,
Minnesota.
2. American Public Health Association, American Water Works Association,
and Water Pollution Control Federation, Standard Methods for the
Examination of Water and Wastewater, 13th Edition, Washington, D.C.
(1971).
3. American Society for Testing Materials, ASTM Standards, Part 23: Water
and Atmospheric Analysis, Philadelphia (1970).
4. Appalachian Regional Commission, Acid Mine Drainage in Appalachia,
Washington, B.C. (1969).
5. Biesecker,J.E., and J.R. George, Stream Quality in Appalachia as Re-
lated to Coal Mine Drainage, 1965, U.S. Geologic Survey Circular
526, Washington, D.C. (1966).
6. Blackman, W. C., Jr., et. al., "Mineral Pollution in the Colorado
River Basin," J. Water Pollution Control Federation. 45 (7),
1517-1557 (1973). ~*"
7. Caldwell, R.D., R.F. Crosby, andM.P. Lockard, "Radioactivity in Coal
Mine Drainage," in Environmental Surveillance in the Vicinity of
Nuclear Facilities, W.C. Reinig, Ed., C.C. Thomas Publisher, Spring-
field, Illinois, pp. 439-445 (1970).
8. Coal Research Bureau, West Virginia University, Underground Coal Min-
ing Methods to Abate Water Pollution: A State-of-the-Art Literature
Review, U.S. Environmental Protection Agency, Water Pollution Control
Research Series, 14010 FKK 12/70, Washington, D.C. (December 1970).
9. Cobb, Ernest D. , and J. E. Biesecker, The National Hydrologic Bench-Mark
Network, U.S. Geological Survey Circular 460-D, Washington, D.C.
(1971).
226
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10. Committee on Interior and Insular Affairs, Subcommittee on Mines and
Mining, U.S. House of Representatives, "Regulation of Strip Mining,"
Hearings before First Session of 92nd Congress, relating to H.R. 60
and Related Bills Relating to the Regulation of Strip Mining; September
20 and 21, 1971; October 21 and 26, 1971; and November 29 and 30, 1971,
Serial No. 92-96, U.S. Government Printing Office, Washington, D.C.
(1972).
11. Committee on Interior and Insular Affairs, Subcommittee on Minerals,
Materials and Fuels, U.S. Senate, "Surface Mining," Hearings
Pursuant to S. Res. 45, A National Fuels and Energy Policy Study,
First Session of 92nd Congress, on S.77, S.630, S. 993, S.1160,
S.1240, S.1498, S.2455 and S.2777, Pending Surface Mining Legisla-
tion; Nov. 16, 17, and Dec. 2, 1971, Serial No. 92-13, Part 1,
U.S. Government Printing Office, Washington, D.C. (1972).
12. Ibid., Part 2
13. Ibid., on S.2777, and S.3000, Bills for Providing for Cooperation
Between the Secretary of the Interior and the States with Respect
to the Regulation of Surface Mining Operations and for Other Pur-
poses, February 24, 1972, Serial No. 92-13, Part 3, U.S. Government
Printing Office, Washington, D.C. (1972).
14. Cox, James L., "Phosphate Waste," Paper presented at First Mineral
Waste Symposium, March 27-28, 1968, Chicago, Illinois.
15. Colorado State University, Water Pollution Potential of Spent Oil
Shale Residues, U.S. Environmental Protection Agency Water Pollu-
tion Control Research Series, 14030 EDB 12/71, Washington, D.C.
(December 1971).
16. Council on Environmental Quality, Coal Surface Mining and Reclama-
tion: An Environmental and Economic Assessment of Alternatives,
prepared for Committee on Interior and Insular Affairs, U.S.
Senate, Pursuant to S. Res. 45, A National Fuels and Energy Policy
Study, Serial No. 93-8 (92-43), U.S. Government Printing Office,
Washington, D.C. (March 1973).
17. Curtis, Willie R., "Strip Mining, Erosion, and Sedimentation," Paper
presented at the 1970 Annual Meeting of American Society of Agri-
cultural Engineers, July 7-10, 1970, Minneapolis, Minnesota.
227
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18. Deely, Daniel J., Orville R. Russell, and Frank J. Wobber, "Applica-
tions of Aerial and Orbital Remote Sensing to the Study of Mined
Lands," Paper presented at Research and Applied Technology Sympos-
ium on Mined Land Reclamation, March 7-8, 1973, Pittsburgh,
Pennsylvania.
19. Dissmeyer, George E., U.S. Forest Service, Atlanta, Georgia,
private communication.
20. Dole, Hollis M., Assistant Secretary-Mineral Resources, U.S.
Department of the Interior, Testimony before the House Sub-
committee on Mines and Mining (Ref. 10), pp. 215-216,
21 September 1971.
21. Doyel, W.W., and S.M. Lang, "NAWDEX--A System for Improving Accessibil-
ity to Water Data," Paper presented at American Water Resources
Association Symposium on Watersheds in Transition, June 19-22, 1972,
Fort Collins, Colorado.
22. Environmental Protection Agency, Methods for Chemical Analysis of
Water and Wastes, Water Quality Office, Cincinnati, Ohio (1971).
23. Environmental Protection Agency, Colorado River Basin Water Quality
Control Project "Radioactivity in Surface Waters of the Colorado
River Basin Radium Monitoring Network, 1968," in Radiation Data
and Reports, pp. 144-147 (March 1972).
24. Environmental Protection Agency, Division of Field Investigations,
Denver Center, Denver, Colorado; EPA Region VII, Kansas City,
Missouri, and EPA Region VIII, Denver, Colorado, Report on Pollu-
tion Affecting Water Quality of the Cheyenne River System, West-
ern South Dakota (September 1971).
25. Environmental Protection Agency, Technical Support Branch, Surveillance
and Analysis Division, Region VIII, Environmental Evaluation of
Mines Development, Inc., Uranium and Vanadium Milling Operations
at Edgemont, South Dakota, Report No. SA/TSB-18, Denver, Colorado
(April 1971).
26. Environmental Protection Agency, Technical Support Branch, Surveil-
lance and Analysis Division, Region VIII, The Meeker Well and
Other Phenomena in the Vicinity of the Meeker Dome, Rio Blanco
County, Colorado: A Summary Report on the Feasibility of Control
of Seepage of Saline Ground Water. Report No. S&A/TSB-15, Denver,
Colorado (December 1972).
228
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27. Federal Water Pollution Control Administration, Region VIII, U.S.
Department of Health, Education, and Welfare, Disposition and
Control of Uranium Mill Tailings Piles in the Colorado River
Basin, Colorado River Basin Water Quality Control Project, Denver,
Colorado (March 1966).
28. Federal Water Pollution Control Administration, Ohio Basin Region,
U.S. Department of the Interior, "Stream Pollution by Coal Mine
Drainage in Appalachia," Attachment A to Appendix C of the Appalach-
ian Regional Commission Report Acid Mine Drainage in Appalachia,
Washington, D.C. (1969).
29. Grube, Walter E., et al., "Characterization of Coal Overburden Mate-
rials and Mine Soils in Advance of Mining," paper presented at
Research and Applied Technology Symposium on Mined-Land Reclama-
tion, March 7-8, 1973, Pittsburgh, Pennsylvania.
30. Halliburton Company, Investigative Mine Survey of a Small Watershed,
Federal Water Quality Administration, U.S. Department of the
Interior, Water Pollution Control Research Series 14010 DM0 02/70-A,
Washington, D.C. (March 1970).
31. Hansen, Clifford P., U.S. Senator from Wyoming, Entry into Record
of Hearings before the Senate Subcommittee on Minerals, Mate-
rials, and Fuels (Ref. 12), pp. 590, 815f, 2 December 1971.
32. Hardaway, John, Environmental Protection Agency, Region VIII,
Denver, Colorado, private communication.
33. Hem, J.D., Study and Interpretation of the Chemical Characteristics
of Natural Waters, Second Edition, U.S. Geological Water Supply
Paper No. 1473, Washington, D.C. (1970).
34. HRB-Singer, Inc., Detection of Abandoned Underground Coal Mines by
Geophysical Methods, Environmental Protection Agency and Pennsylvania
Department of Environmental Resources, Water Pollution Control
Research Series 14010 EHN 04/71, Washington, D.C. (April 1971).
35. Keller, W.D., "Clays (Survey)," in Kirk-Othmer Encyclopedia of
Chemical Technology, Vol. 5, pp. 541-560 (1964).
36. Lang, S.M. and W.W. Doyel, "A National System for Exchange of Water
Data," Bulletin of the International Association of Hydrological
Sciences, 17_, 435-41(1972).
229
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37. Langford, Russell H. and George H. Davis, "National System for Water
Data," J. of the Hydraulics Division, Proceedings of The American
Society of Civil Engineers. 96(HY7), 1391-1401 (1970).
38. Lorenz, Walter C. and Robert W. Stephen, "Factors that Affect the
Formation of Coal Mine Drainage in Appalachia," Attachment C to
Appendix C of the Appalachian Regional Commission Report Acid
Mine Drainage in Appalachia, Washington, D.C. (1969).
39. Ibid., "The Oxidation of Pyrite Associated with Coal Mines," Attach-
ment D to Appendix C of the Appalachian Regional Commission Report
Acid Mine Drainage in Appalachia, Washington, D.C. (1969).
40. May, Robert F. . Predicting Outslopes of Spoil Banks, U.S. Forest
Service Research Note CS-15, Central States Forest Experiment
Station, Columbus, Ohio (November 1963).
41. Morth, Arthur F., Edwin E. Smith, and Kenesaw S. Schumate, Pyritic
Systems: A Mathematical Model, Environmental Protection Agency
Report EPA-R2-72-002, Washington, D.C. (1972).
42. National Coal Association, Bituminous Coal Facts 1972. Washington,
D.C. (1972).
43. Ohio State University Research Foundation, Acid Mine Drainage Forma-
tion and Abatement, Environmental Protection Agency, Water Pollu-
tion Control Research Series DAST-42, 14010 FPR 04/71, Washington,
D.C. (April 1971).
44. Qaism, S.R., "Water Quality Estimates for Rivers in Appalachia
Mine Drainage Regions," Appendix D to Appendix A of the Appa-
lachian Regional Commission Report, Acid Mine Drainage in Appa-
lachia, Washington, D.C. (1969).
45. Rouse, Jim V., Environmental Protection Agency, National Field
Investigations Center, Denver, Colorado, private communication.
46. Salotto, B.V., et al., "Determination of Mine Waste Acidity," Federal
Water Quality Administration, Cincinnati, Ohio, January 1967.
47. Sceva, Jack E., Water Quality Considerations for Metal Mining Industry
in the Pacific Northwest, Draft Report, Environmental Protection
Agency, Region X, Seattle, Washington (1973).
48. Scott, Robert, Environmental Protection Agency, Region IX,
San Francisco, California, private communication.
230
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49. Shea, Evan P., John W. Nebgen, and Ford Bohl, Midwest Research
Institute, Study of Wastewater Systems. Report to American
Petrofina Company of Texas, El Dorado, Kansas (September 1971).
50. Struthers, P.H., "180,000 Stripmine Acres: Ohio's Largest Chemical
Works," Ohio Farm and Home Research, 46(4)(July-August 1961).
51. Tybout, Richard A., "A Cost-Benefit Analysis of Mine Drainage,"
paper presented at Second Symposium on Coal Mine Drainage Research,
May 14-15, 1968, Pittsburgh, Pennsylvania.
52. U.S. Army Corps of Engineers, "The Incidence and Formation of Mine
Drainage Pollution in Appalachia," Appendix C to the Appalachian
Regional Commission Report Acid Mine Drainage in Appalachia,
Washington,D.C. (1969).
53. U.S. Bureau of Mines, Environmental Effects of Underground Mining
and Mineral Processing, Unpublished Report, Washington (1968?).
54. U.S. Bureau of Mines, Minerals Yearbook, 1971, U.S. Department of the
Interior, Washington, D.C. (1972).
55. U.S. Department of the Interior, Surface Mining and Our Environment:
A Special Report to the Nation, U.S. Government Printing Office,
Washington, D.C. (1967).
56. U.S. Geological Survey, Office of Water Data Coordination, Catalog
of Information on Water Data: Index to Areal Investigations and
Miscellaneous Water Data Activities, Washington, D.C. (1970).
57. Ibid., Catalog of Information on Water Data: Index to Groundwater
Stations, Washington, D.C. (1968).
58. Ibid., Catalog of Information on Water Data: Index to Surface
Water Section, Washington, D.C. (1970).
59. Ibid., Catalog of Information on Water Data: Index to Water Quality
Data: Index to Water Quality Section, Washington, D.C. (1970).
60. Ibid., Catalog of Information on Water Data: Maps Showing Locations
of Groundwater Stations, Washington,D.C. (1968).
61. Ibid., Catalog of Information on Water Data: Maps Showing Locations
of Water Stations, Washington, D.C. (1970).
231
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62. Ibid., Catalog of Information on Water Data: Maps Showing Locations
of Water Quality Stations, Washington, D.C. (1970).
63. Ibid., Design Characteristics for a National System to Store, Retrieve,
and Disseminate Water Data, Federal Interagency Water Data Handling
Work Group, Washington, D.C. (October 1971).
64. Ibid. , Recommended Methods for Water Data Acquisition: Preliminary
Report, Federal Interagency Work Group on Designation of Standards
for Water Data, Washington, D.C. (1972).
65. Vimmerstedt, J.P. , J.H. Finney, and P. Sutton, "Infiltration of
Water on Strip-Mine Spoil Banks," in Effect of Strip Mining on
Water Quality, Water Resources Center, Ohio State University,
Office of Water Resources Research Project B-002-OHIO, 14-01-
001-841, Columbus, Ohio (1973) (PB 217-872).
66. Vimmerstedt, J.P. , and P.H. Struthers, "Influence of Time and Pre-
cipitation on Chemical Composition of Spoil Drainage," paper
presented at Second Symposium on Coal Mine Drainage Research, May
14-15, 1968, Pittsburgh, Pennsylvania.
67. Weigle, Weldon K. , Designing Coal-Haul Roads for Good Drainage,
Central States Forest Experimental Station, U.S. Dept. Agricul-
ture, Forest Service, Columbus, Ohio (1965).
68. Weigle, Weldon K. , "Erosion from Abandoned Coal-Haul Roads,"
Journal of Soil and Water Conservation, (3), 96 (1966).
69. Wentz, Dennis, Effects of Mining on Surface Water Quality Ex-
clusive of Uranium Mining in Colorado, U.S. Geological Survey,
Water Resources Division, Colorado District, Denver, Colorado,
to be published.
70. West Virginia University, Division of Plant Sciences, College of
Agriculture and Forestry, Mine Spoil Potentials for Water Quality
and Controlled Erosion, Environmental Protection Agency, Water
Pollution Control Research Series 14010 EJE 12/71, Washington,
D.C. (December 1971).
232
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6.0 CONSTRUCTION
6.1 Introduction
The accelerated rise in the U.S. population through the year
2000 will require the daily development of about 1,600 hectares (about
4,000 acres) ' of land to accommodate the expanded requirements for
new housing and related services, transportation, utilities, communica-
tions, and sewer and wastewater treatment networks — all of which are
construction oriented. Land areas sufficient to accommodate these new
operations must be found without limiting those land and water resources
needed to produce the food supplies essential to the sustenance of in-
creased numbers of plants, animals, and man. At the present time, more
than two-thirds of the U.S. population is located in urbanized areas
covering 77o of the land area.
This section will identify the types of construction activities,
the sources of land and water pollution associated with these construc-
tion practices, and the types of water pollutants generated during con-
struction activities. The physical, chemical, and biological aspects of
pollutant transport are discussed, and the status of methods for predict-
ing pollution from construction activities is presented.
Emphasis is placed on the fact that environmental impacts of
construction must be assessed on a site-by-site basis. As used in this
section, construction activity refers to major jobs, characterized in
part as heavy (as in damsites and other excavations), highway, housing
developments, transmission and pipelines, dredging, and demolition
operations—whether done in an urban or rural environment.—-—
Construction practice refers to timber clearing, grubbing, and topsoil
stripping; rough grading, concrete, asphalt and other facility operations;
waste disposal; soil stabilization, fertilization, and revegetation;
traffic control; pest control, and site restoration following construction.
This term includes all job operations that generate various types of water
pollutants by spillage, erosion, sedimentation, and stormwater runoff.
6.2 Types of Construction Activity
Activities likely to result in a modification of the physical,
chemical, and biological properties of land and water resources include:
construction of transportation and communications networks; housing;
office buildings and related land developments; energy networks; water
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resource developments; as well as ski slopes, parks and other multiple
use recreational developments.
6.2.1 Transportation and communications networks: These
activities include interstate highways, roads, streets and trails, sub-
ways and railroads, and telephone lines over or under the land surface.
Also included are airports, harbor facilities, microwave communication
towers, radar installations, bridges, and tunnels.
6.2.2 Housing, office buildings and related developments:
Included under this item are individual and high-rise housing developments,
shopping centers, high-rise office buildings, schools, and industrial and
commercial centers.
6.2.3 Energy networks: These include hydroelectric, fossil
fuel, and nuclear power plants, and their associated electric power
transmission lines, over or under the land surface. Also included are
natural gas and petroleum pipelines, both above and underground.
6.2.4 Water resource development and usage: Under this item
are construction activities such as dams and reservoirs, inland waterways,
water pipelines, irrigation channel systems, temporary water impoundments
for stormwater management, and major flood control works.
6.2.5 Ski slopes, parks and other multiple use recreational
developments: Construction operations included in this category are the
clearing and grading of steeply sloping ski runs, and the installation
of water lines, sewer lines, power lines, and wastewater treatment
facilities. Also included are the construction of roads and other
transportation and communications facilities contiguous to the recreational
area.
6.3 Sources of Water Pollution
Construction operations are capable of generating many types
of water pollutants. The amount and type of pollutants generated during
construction will depend upon the type and time duration of the various
construction practices, the location and size of the construction site,
the rainfall distribution and frequency, pest control measures, the
resistance of the soil or land surface to erosion by gravity, water, and
wind, the chemical properties and geology of subsurface soils, and the
number of people and machines linked with each construction site. Thus,
construction of a large dam would require extensive concrete operations
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(aggregate processing and washing plants, etc.) within a relatively small
area and in close proximity to a vulnerable waterway. Concrete operations
for the construction of a highway remote from a vulnerable waterway, on
the other hand, would present less severe water pollution problems.
These examples illustrate an important point: the location of
the construction activity relative to environmentally vulnerable water-
ways, groundwater recharge areas, etc., is crucial to construction practice.
Construction practice typical of a given site will involve the
following: clearing, grubbing, and pest control, rough grading, facility
construction, and the restoration of staging and stockpile areas on com-
pletion of the job. These practices comprise the prime source of various
types of water pollutants resulting from construction.
6.3.1 Clearing, grubbing, and pest control: These three
operations may appear initially on any construction site, singly, or in
combination. Their extent will be greatest in the construction of trans-
portation and energy networks, particularly superhighways, electric trans-
mission lines, and pipelines for oil and natural gas. Unwanted vegetation
such as trees, shrubs, or tall grasses that constitute a hindrance to the
development of the site will be cleared from the right of way, or the
construction site. In some instances, the surface soil may be stripped
and stockpiled for use during site restoration. Unwanted buildings or
other man-made structures may be demolished or moved to new locations.
All of these operations can be viewed as a major disturbance
of the land surface, with possible deleterious effects on the ecology of
the development site, adjacent areas, and contiguous water resources.
Cutting of trees, other woody plants, and grasses can produce
large volumes of timber and wood waste. Some of the timber can be con-
verted to lumber, plywood, or pulpwood. Remnants of trees such as large
branches and stumps can be converted to wood chips, buried in preselected
disposal sites, or selectively burned. Special contrivances are being
used in some states that allow complete burning with little or no smoke.
Preparation of wood chips is the preferred method of disposal of wood
wastes, because they serve as protective mulches on cut and fill slopes,
access roads, and certain staging areas.
Pest control can take the form of spraying the site with
insecticides, herbicides, or rodenticides, to remove insects harmful to
man, herbaceous and woody plants that obstruct development, or unwanted
animals.
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6.3.2 Rough grading: This practice is characteristic of
essentially all construction activities, with particular reference to
highway cuts and fills, excavations for dams and pipelines, and housing
and related land developments. Heavy construction equipment used in
this practice (bulldozers and trucks) becomes both a direct and indirect
source of water pollutants. Diesel fuel, oil, and lubricants are direct
sources of water pollution. These petroleum products are insoluble in
water and form oily films that can alter the diffusion of oxygen in the
water body with harmful effects on the growth of phytoplankton and
fish.
Construction equipment causes severe compaction of clayey soils,
thereby curtailing the rate of water infiltration and lowering the rate
of soil aeration. If these factors are ignored, the revegetation of
graded areas will be considerably more difficult.
Grading results in the exposure of extensive subsoil areas which
characteristically possess soil aggregates that are more easily dispersed
by the impact of raindrops and wind than that of unexposed soils. Sedi-
ment particles (fine sand, silt, clay, and organic particles) caused by
the erosion of soil exposed during grading is one of the most serious
water pollutants. For example, up to 7.6 hectares of soil per kilometer
of superhighway (30 acres per mile) may be exposed during construction.
Under heavy rainfall, and the lack of proper erosion control measures,
up to 1,696 metric tons of sediment per kilometer (3,000 tons per mile)
can be produced. Much of this sediment (fine sand and silt) can be
deposited on adjacent properties, in the smaller water bodies, and ulti-
mately in major water bodies. Sediment deposited on the bottom of streams,
lakes, and reservoirs, (fine sand and silt) threatens the survival of
shellfish and other bottom dwelling aquatic species. •*'~^/ Clay particles
of colloidal dimension that remain in suspension, creating water turbidity
for long periods of time, can decrease the amount of light in the water
column of lakes, and as a result decrease the rate of photosynthesis and
the productivity of aquatic species located therein.
The turbidity caused by sedimentation of lakes and reservoirs
can increase the absorption of heat, thereby increasing the surface water
OQ /
temperature relative to clear water.-25L.1 The warmer surface water is less
dense than the cold bottom water, hence it remains confined to the surface
strata. If the reservoir discharges only from the surface, this warmer
water may have far-reaching effects on stream ecology below the damsite.
Finally, pesticides and other chemicals adsorbed on sediment may be trans-
ported to lakes and streams in runoff water, where they accumulate in
bottom deposits. These chemicals can be released slowly to overlying
lake waters and thereby become concentrated at successive levels of the
236
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oo /
food chai.n.——' Oil films may serve as a medium for concentrating water
insoluble insecticides. Sediments may also serve to transport plant
nutrients, primarily calcium, magnesium, and trace elements such as iron
and manganese.-^ Trace metals such as copper, cobalt, and chromium
are transported in rivers largely by fixation within sediment crystalline
structures.——
6.3.3 Facility construction: This practice refers largely
to core drilling, foundation grouting, and concrete operations during
the construction of transmission structures, highways, buildings, and
dams. Also included are dust control operations in which oil, calcium
chloride, and water are used on access and haul roads, and on graded
areas subjected to heavy truck traffic.
Some of these operations will be carried out directly in
waterways. These include the diversion of streams necessary for the
construction of cofferdams, revetments, and dikes which result in bottom
deposits of sand and silt that can damage the production of shellfish
and other bottom species. Finally, other operations under this heading
refer to the construction of shops and storage areas, and asphalt opera-
tions.
Concrete operations are a source of pollutants through washing
spillage, and waste of various materials. Large volumes of water are
also used in the washing of sand and stone aggregates J=Li^=2jL=i2/ Major
pollutants include spilled cement, fuels, bituminous materials, and cur-
ing compounds. These materials may contain the trace elements cobalt,
chromium, manganese, and lead which are recognized water pollutants.
Facility construction activities yield solid wastes from construction
camps, shops, and storage areas (including junk, scrap, trash, and sani-
tary wastes) which are potential water pollutants, as are insecticides
and rodenticides used around the construction site.
(a) Transmission structures'.—*— The construction of
electric power transmission systems, and pipelines for natural gas,
petroleum, and water will involve the use of clearing, grading, ditching,
stripping of surface soil, topsoil stockpiling, stream diversions and
cofferdam construction. Access and haul roads, campsites, and setup
sites are an integral part of these operations. All of these practices
can generate appreciable amounts of sediment and runoff.
(b) Highways, roads, and streets; The pollution sources
in highway construction are essentially the same as those for transmission
structures. One difference relates to the greater amount of grading,
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excavation of cut and fill areas, and the larger number and size of
construction vehicles, and greatly increases the runoff and erosion
potential of the soil surface. Highway construction is also a source
of pollutants such as sediment, fuel, grease, oils, wastewater from
concrete operations, concrete spillage, pesticides, fertilizers, sanitary
wastes, and solid wastes.
(c) Buildings; As with the construction of highways, the
construction of new buildings can have important pollutional effects on
the environment. Special environmental problems in building construction
refer to traffic flow around the job site, the methods of hauling and
disposal of spoil and debris, time of day for scheduling demolition
operations, facilities for washing concrete mixers and haul trucks, and
the control of mud and sediment during construction. '-—/
Sediment clogging of storm sewers can become a serious
problem in certain housing subdivision developments, especially when
curbing and storm drains are installed, and the roads are paved
long before the housing is fully constructed. Thus, rainstorms impact-
ing on exposed soils as the individual houses are built throughout the
subdivision can generate sediment loads that ultimately clog the storm
sewer.
(d) Dams: The construction of large dams involves many
operations which can serve as sources of sediment and other pollutants
during construction. Construction haul roads are potential sources of
large quantities of sediment and construction related pollutants, particu-
larly if the roads are improperly designed and contructed. Large areas
of forested hillsides are often cleared and stripped to permit excavation
and construction of the dam, dike, spillway, and the downstream portal
of the outlet works. Also, spoil storage, and shop and equipment areas
are often located at the downstream end of the dike embankment, and along
the valley floor up to the center portions of the flat peninsula of the
main embankment.±±J Turbid water is emitted from the dewatering of the
damsite, the tunnel excavation, the batch plant, channel change areas,
and downstream service yard areas. These waters become polluting waters
unless they are treated in settling ponds or in clarifiers before being
allowed to enter the waterway.ffi / Finally, water impoundments can
inundate several miles of free-flowing river and lands adjacent to the
river. The nutrients, vegetative debris, pesticide residues, residues
and wastes from animal life, bacteria, and mineral elements inventoried
in the impoundment area automatically become sources of pollution in the
impounded water. Accumulated wastes from inundated animal feedlots
would, for example, provide a large initial inventory of nutrients and
organic matter.
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6.3.4 Site restoration: This practice refers to operations
such as cleanup of the site, final grading, loosening and tillage of
compacted soils, establishment of permanent vegetation, restoration of
any damage to trees and shrubs caused by construction operations, removal
of any temporary stream fording structures or sediment control structures,
removal of temporary construction facilities such as access and haul
roads, reshaping, stabilization and revegetation of borrow pit and stock-
pile areas, removal of office and work area structures, and any other
practice that reestablishes a harmonious landscape capable of withstand-
ing erosion by water, wind, ice, and gravity.
These operations will vary in detail from site to site, but
those involving site cleanup, final grading, and the establishment of
permanent trees, shrubs, grasses, and groundcovers will be carried out
on any construction site, in accordance with the erosion and sediment
control plan, the construction contract, and the landscape plan.
6.4 Types of Pollutants*
6.4.1 Sediment: Sediment is one of the greatest pollutants
resulting from construction activity. Sediment includes solid and organic
materials transported by rainfall runoff, wind, ice, and the pull of
gravity. Sediment carried by the wind is usually deposited in places
where the wind motion is obstructed by trees, grass and buildings--
where the wind energy of motion vanishes. The magnitude of wind erosion
is greatest on construction sites situated in deserts and dry soil
surfaces composed largely of silt particles. Sedimentation caused by
rainfall and runoff from construction sites is deposited downstream or
in other receiving waters such as ponds, reservoirs, and dams. Sediment
deposition occurs under some of the following conditions: when runoff
carries a sediment load requiring more energy to carry than the runoff
can furnish; when the runoff is intercepted by a grassed waterway, slow-
flowing stream, or water impoundments such as ponds and reservoirs, and
when the sediment consists of large soil particles that settle fast due
to the force of gravity.
Major factors responsible for the loss of soil from construction
areas include the clearing of large areas of land at one time, rather than
in stages. Oftentimes the lack of a well planned grading schedule results
in the exposure of surfaces during heavy rain seasons when the amount of
runoff is greatest.
* References: 3, 4, 6, 10, 18, 21, 26, 27, 30, 34, 37, 41, 43, 44,
52, 53.
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Sediment has physical, chemical and biological effects on the
receiving stream and water bodies. Physical damage resulting from sediment
deposition includes: the reduction of storage capacity; filling harbors
and navigation channels; increasing the frequency of flooding resulting
in increased bank erosion; increasing suspended solids (turbidity) that
reduce light penetration; increasing the cost of water treatment; damag-
ing fish eggs and gills; destroying and covering organisms on the beds
of streams; reducing the flowing speed and carrying capacity of streams;
increasing the cost of maintenance through frequent dredging; destroying
and impairing drainage ditches, culverts, and bridges; altering the shape
and direction of stream channels; destroying water recreational areas•
and imparting undesirable taste to water. Biological agents such as soil
organisms, and pathogens from human and animal sanitary wastes are also
carried by sediment in runoff.
-'..
6.4.2 Chemical pollutants:" Chemical pollutants are
generated from various operations and materials used throughout various
construction activities. Chemical pollutants originate from inorganic
and organic sources. These sources may be in solid form in such construc-
tion materials as boards and fibers; and in liquid form, as in paints,
oils, and glues. Organic materials have been gaining wider use in the
manufacture of construction materials. The effects of the decomposition
of these materials on water quality is unknown at present.
Pipes, beams, structural frames, boards, and lining materials
are some of the major construction materials now being made out of syn-
thetic organic chemicals to supplement lead, steel and iron products.
Some of the major organic chemicals and products that are being used
for the production of construction materials and tools include polyvinyl
chloride, thermoplastic polyesters, and epoxy fibers.
Synthetic and nonsynthetic organic liquid chemicals are widely
used for surface treatment of walls, sealing cracks in roofs and floors,
gluing materials together, and in liquid and spray paints. Fuels
are used as energy sources in construction activities. They include
oils, gasoline and diesel fuel as used in trucks, power generators,
backhoes, bulldozers and other construction equipment. Other organic
materials used in construction activities include fertilizers, pesti-
cides, plastics, rubbers, and curing agents.
The second group of chemical materials is derived from inorganic
minerals. Mineral products provide the greater percentage of construction
materials in use today. Metals, rocks, earth, and chemicals derived from
* References: 1, 2, 5, 9, 13, 14, 20, 24, 31.
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minerals are widely used in the production of pipes, rods, structural
frames, and construction machinery.
The major categories of chemical pollutants are: petroleum
products, pesticides, fertilizers, synthetic organic materials, metals,
soil additives, construction chemicals, and miscellaneous wastes--
construction debris.
(a) Petroleum products'. Petroleum products are the largest
group of materials consumed in construction activities. Petroleum prod-
ucts consist of oils, grease, fuels, certain solvents, and many others.
Pollutants from construction activities include crank case oil wastes,
leaky storage containers, oil solvents, dust control oils, minor oil
spills during transfers and transportation, oil laden rags, and degreasers.
A majority of these materials float over the surface of
the water and spread easily over a wide area. It has been estimated
that a gallon of oil can pollute an area of four acres. Oils and other
petroleum products are readily absorbed by sediment which is the main
carrier of these materials. Sediment contaminated with oil is carried
in runoff to receiving streams. The inherent properties of petroleum
products make them extremely difficult to control after entering water
bodies.
The extent of water pollution caused by petroleum products
at construction sites is dependent on the occurrence of major spills from
storage tanks; the quantity of crank case oil wastes disposed of from a
construction site; the number of trucks and construction equipment oper-
ated, and the state of their maintenance; and the magnitude of the con-
struction activity. Definitive quantitative figures based on the above
criteria have not been developed.
Some petroleum products impart a persistent odor and taste
to waterj impairing its use for drinking water and contact sports.
Many oils have the ability to block the transfer of air from the atmos-
phere into water, resulting in the suffocation of aquatic plants, organ-
isms, and fish. Some petroleum products contain quantities of organo-
metallic compounds (nickel, vanadium, lead, iron, arsenic) and other
impurities which can be toxic to fish and other organisms.
(b) Pesticides: The three most commonly used pesticides
at construction sites are herbicides, insecticides, and rodenticides.
Herbicides are used for removing weeds and other undesirable plants
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growing around the construction area. Their use is limited, since most
plants are removed by bulldozers during land clearing and grubbing.
Insecticides are widely used on construction sites. The
particular insecticide used is controlled by the geographical area,
climate, and the insect type. Rodenticides are also widely used, depend-
ing upon essentially the same factors mentioned for insecticides.
Pesticides are transported to receiving waters by runoff
from construction sites. Improper methods of application will result in
direct contamination of water, or in drift which settles in surface waters.
(c) Fertilizers: One of the most effective means of
reducing soil erosion and sedimentation from construction activities is
the early establishment of vegetation on the exposed soil surfaces. The
addition of commercial fertilizers promotes vegetative growth, and thus
helps to prevent the loss of soil. Nitrogen and phosphorus are the major
plant nutrients needed for the successful establishment of vegetation
on most subsoils. Limestone is needed for the neutralization of acid
subsoils exposed to the surface as a result of land clearing, trench
digging, and backfilling of construction areas.
Heavy use of commercial fertilizers can add nitrogen and
phosphorus to receiving waters and thus accelerate the eutrophication
process.
(d) Synthetic organic materials: The construction industry
utilizes many different types of synthetic products. These include
structural frames, window panes, wall board, paints, and many others.
Heavy duty construction materials are synthesized from nondegradable
organic materials. They are little affected by biological or chemical
degradation agents, and are usually designed to withstand the most
severe physical conditions.
(e) Metals: The concern over metal pollution of water
bodies is associated mostly with the heavy metals (mercury, lead, zinc,
silver, cadmium, arsenic, copper, aluminum, iron, etc.). Metals are
used extensively in construction activities for structural frames,
wiring, ducts, pipes, beams, and many other uses. Construction vehicles,
gasoline, paints, pesticides, fungicides, and construction chemicals are
also potential sources of heavy metals pollutants. When these latter
materials are weathered, decomposed and disintegrated by various agents,
they ultimately form oxides and salts that can affect aquatic organisms.
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(f) Soil additives: Soil additives are chemicals and
materials that are applied to the soil during construction activities
in order to obtain desired soil characteristics. Oftentimes construction
activities cover large areas consisting of several different types of
soils. The nature of soils is dependent on the climatic, topographic
and geological conditions. The type of soil additive applied depends
on the objectives of the construction activities. Soils may vary from
one location to another in the amount of water they contain, particle
size distribution (clays, silt, sand and gravel), water infiltration
rate, ability to support heavy structures, and resistance to compaction
by construction equipment. Soil additives are used to control the amount
of moisture absorbed by roadway surfaces, to reduce the degree of shrink-
ing and expanding of clay soils in order to prevent structural damage of
buildings and air field runways, and to increase the firmness of soils.
Several chemicals and materials are used to obtain desired
soil properties. Commonly used materials include lime, fly ash, asphalt,
phosphoric acid, salt, and calcium chloride. The soil additives carried
in runoff from construction sites alter the quality of receiving waters.
However, little work has been conducted to show the net environmental
effects of these soil additives.
(g) Construction chemicals: Many types of chemicals are
used in construction for purposes such as: pasting boards together, seal-
ing cracks, surface treatment, solvents for oils and paints, and dyeing
and cleaning. The amounts of chemicals leaving construction sites as pol-
lutants have not been established. Poor construction activities that are
liable to contaminate water resources include the following practices:
dumping of excess chemicals and wash water into storm water sewers; indis-
criminate discharding of undiluted or unneutralized chemicals; disregard
for proper handling procedures resulting in major or minor spills at the
construction site; and leaking storage containers and construction equipment.
6.4.3 Biological pollutants-. '^5 / Biological pollutants from
construction include soil organisms and organisms of human and animal
origin. They include bacteria, fungi, and viruses. The majority of
biological pollutants are found in the topsoil layer where they can feed
on dead plants, animals, birds and other organisms.
The biological pollutants resulting from construction activity
that indicate the greatest pollution potential are those of animal and
human origin. These biological pollutants are more prevalent on construc-
tion sites where improper sanitary conditions exist. These biological
organisms can be either pathogenic (disease causing) or nonpathogenic to
humans and animals. Sediments and runoff are the major carriers of these
uncontrolled organisms from construction sites. Common pathogenic organisms
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that are significant health hazards include Vibrio cholerae that causes
cholera (a major menace in societies with inadequate water supply facili-
ties) ; Salmonella typhi and Salmonella paratyphi that cause typhoid fever
and paratyphoid fever, respectively, and Shigella dysenteriae that is
responsible for dysentery.
Sludge from wastewater treatment plants, often used as a fertili-
zer during the restoration of graded areas, could serve as a source of
pathogenic organisms if they have survived the wastewater treatment pro-
cess. The effects of sewage sludge as a source for degrading water quality
is wholly dependent on the effectiveness of the prior treatment processes
in destroying these harmful organisms, the quantities of sludge applied,
the geographic and climatogological area, and proximity of the receiving
waters to the treated area.
9,29 /
6.5 Methods of Pollutants Transport '
A number of agents are directly or indirectly responsible for
the transportation of pollutants from construction areas to receiving
streams. These include runoff, infiltration, wind, seepage, landslides,
and mechanical agents. Erosion and runoff cause the greatest soil loss
from construction sites. Runoff increases markedly after the rate of
water infiltration is decreased. This occurs when the soil's capacity
to store free water reaches a maximum. Large masses of suspended sedi-
ment resulting from exposure of soils to runoff on construction sites
may be washed into waterways. Oils, trash, and other construction debris
are also carried in suspension until they are deposited in receiving
streams. Sediment is the most important of all the suspended pollutants
carried in runoff because of its massive volume, its effects on the environ-
ment, and its difficulty of control.
Many chemical and biological pollutants generated at construc-
tion sites are adsorbed or fixed to sediments. The forces that are
responsible for the transportation of sediment also affect the movement
of other pollutants such as fertilizers, oils, heavy metal salts and
oxides, and other construction related chemicals that are carried with
sediment either in suspension or as dissolved materials. Construction-
related solid wastes carried by runoff include: paper, beer cans,
beverage cans, aluminum foil, and plastic wrappers. Petroleum oils
form a thin film over the surface of water, and can be carried over
long distances and wide areas.
A second agent for transporting pollutants is wind. Wind car-
ries particles of contaminated soil particles and spray chemical droplets
to areas far removed from construction sites. It is customary to en-
courage the clearing of construction sites during dry periods in order
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to reduce the amount of soil erosion due to runoff. This practice could
encourage wind erosion if dry conditions exist for extended periods of
time. Limited data exist on the quantity and effects of wind-deposited
sediment derived from construction sites on receiving waters. Wind is
also responsible for the transportation of insecticides, herbicides, and
other pesticides that are applied as aerial sprays. These chemical pollut-
ants are carried in air drifts to water courses and other areas where
they can be toxic to nontarget plants, insects, and aquatic organisms.
Transportation of pollutants from construction by infiltration
and seepage has been relatively unstudied. Construction activities close
to the water table, such as construction of septic tanks or basements,
can result in the infiltration of coliform bacteria and domestic chemicals
to the water table. A limit of 4-8 ft of soil between septic tanks and
the water table is recommended by many public works agencies as a means
of controlling pollution from infiltration of sanitary wastewater.
Seepage involves the movement of pollutants from below the
ground up to the soil surface. One of the oldest and most common methods
of disposing of chemical and oil wastes is burial. After a period in the
ground, these chemicals can be carried to the surface where they may be
carried in runoff to nearby streams and reservoirs. This type of move-
ment of buried chemicals could be severe depending on the quantities
buried, the nature of the soil (very porous or nonporous) and the amount
of water seeping to the surface.
The nature of the pollutants plays an important role in the
degree to which they can be transported through seepage and infiltration.
Dissolved solids and liquid chemicals are more likely to be transported
through these processes than suspended particles. The latter have the
tendency to seal off the pores necessary for the movement of water. The
chemical activity of the pollutants is also important. Cations such as
sodium and zinc that are strongly adsorbed by clay particles will be
retained in the surface soils. Less strongly adsorbed anions such as
chlorides and nitrates will more easily contaminate groundwater.
Wash water and solvents are often dumped in areas close to
waterways or into sewers. It is common practice to clean concrete mixers
near open gutters and storm sewers. Similar practices are common when
cleaning oily hands, tools and machinery. Finally, pollutants in the
construction area become dispersed widely by the movement of machinery.
Spilled chemicals and crankcase wastes, for example, are subject to
dispersal by movement of dozers and trucks.
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6,6 Quantification of Pollution from Construction Activities
Quantification methods for pollution from construction activities
are available only for soil erosion, and suspended sediment yield. Methods
are not available for other pollutants such as petroleum products, con-
struction chemicals, pesticides, etc.
The following sections present the extent of soil erosion from
construction sites; erosion prediction methods; and methods for collection
of data for quantification of erosion and sediment, including literature
survey, field survey, and stream water quality sampling.
6.6.1 Extent of soil erosion: Construction of highways,
housing developments, shopping centers, water resources projects, recrea-
tional facilities and large manufacturing centers tends to denude each
44 /
year nearly 600,000 hectares (1.5 million acres) ' of land of its soil
cover, and produces huge quantities of sediments from erosion processes.
Sediment is the greatest pollutant in quantity, and carries other water
pollutants as well. The chemical and biological significance of these
pollutants in water quality is of concern in protection of water resources.
Soil erosion from construction sites is a significant environmental threat
and special legislation in several states is under consideration, follow-
ing the pioneering efforts of Maryland. The extent of sediment load may
be appreciated by an example of the relative contributions from rural areas
and from land under development in Maryland. The rural areas in the Potomac
and Patuxent River Basins, under normal conditions, contribute less than
9 0
70 metric tons/km/year (200 tons/mile/year) of sediment, while land
under development in this same region has been found to contribute from
354-42,350 metric tons/km2 (1,010-121,000 tons/mile2) per year / Guy
and Ferguson / reported that the movement of sediment from concentrated
residential construction at Kensington, Maryland, might exceed 17,500
metric tons/km2 (50,000 tons/mile ) while the sediment movement from
several "natural" drainage basins in Pennsylvania and Virginia near the
Washington, B.C., area is generally less than 70 metric tons/km2 (200 tons/
mile2) per year. In the case of the Potomac River, about 25% of the 2.27
million metric tons (2.5 million tons) of sediment dumped into the tidal
estuary is produced in the immediate vicinity of the Washington Metropolitan
Area, which represents only about 2% of the total drainage area of the
basin. 2LJ
Urban construction can result in increasing the velocity of
surface runoff during storms as well as increasing the amount of sedi-
ment transported. When urban construction in the Bel Pre Creek area in
Maryland increased by 157» on a pasture/woodland, Yorke and Davis^2/ ob-
served that storm runoff increased 307o and suspended sediment increased
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14%. They also observed a direct relationship between the amount of
construction and the sediment yield of a basin.53/
46 /
Vice, et al. , reported on a study conducted in northern
Virginia. They analyzed the sediment yields from 88 storm events repre-
senting overland runoff from 1961 to 1964, and showed that: (1) the
mean concentration of sediment in the flow increased as the amount of
flow in a given storm increased; (2) the concentration and sediment yield
varied considerably depending on the area exposed during construction
and how rapidly remedial measures took effect; and (3) an average of
72.5 hectares (179 acres) of construction area (6% of the drainage
area) contributed 94% of the 33,500 metric tons (37,000 tons) trans-
ported from the basin during a 3-4 year period of record.
In a U.S.G.S. study of the Scott Run Basin near Washington, D.C.,
85% of the sediment transported into the basin came from highway construc-
tion which covered only 117» of the 11.6 km^ (4.5 miles^) basin.-=-=-' Under
conditions of normal precipitation, sediment yield in the construction
area would be about 16,800 metric tons/km^ (48,000 tons/mile^) annually.
This amount is about 10 times that normally expected from cultivated
land, 200 times that expected from grassland, and 2,000 times that expected
from forestland.i?-'
6.6.2 Prediction of soil erosion: Erosion can occur in two
ways: through the effects of wind action or water movement. The trans-
port of eroded material by wind action appears to be of regional signifi-
cance; though important in arid western states, it tends to have limited
impact on overall water quality. Prediction of soil loss by wind erosion
o o /
in the United States has been described by Skidmore and Woodruff-=^/ in
Agriculture Handbook No. 346 of the ARS-USDA.
Water erosion may occur in two ways: sheet erosion and channel
erosion. Sheet erosion is usually associated with the removal of uniform
soil layers through the action of raindrop splash and transport of loosened
soil by overland flow. Rill erosion is closely associated with sheet
erosion. The formation of rills indicates the concentration of overland
flow and marks the transition from sheet erosion to the channel erosion
process. Channel or gully erosion is normally created from accelerated
erosion of rills and other depressions of the surface which tends to con-
centrate the surface runoff. Thus, channel erosion is created by con-
centrated flow. Sheet erosion represents a major mechanism for soil loss
from overland flow.
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The methods of predicting soil loss from cropland by sheet
erosion were documented in this report under Agriculture (Section 3.0).
Methods developed by Musgrave (1947), and Wischmeier and Smith (1965)
are used for predicting on-site erosion of cropland in order to design
adequate soil conservation practices.
90 /
(a) Musgrave equation: Musgrave ' reported the results
of analyses of soil-loss measurements for some 40,000 storms occurring
on fractional acre plots in the U.S., and proposed the following empiri-
cal relation:
E, inm3=12IRS1-35L°-35P301-75
E, in acre in. - IRS1'35 L°'35
(6-1)
where E is the soil loss, I is the inherent erodibility of the soil
in centimeters (inches). R is a cover factor, S is the degree of
slope in percent, L is the length of slope in meters (feet) and P3Q
is the maximum 30-min amount of rainfall, 2-year frequency in centimeters
(inches). The equation (6-1) is applicable to long-range average soil
losses for broad areas.
Data are not available to show the applicability of the
Musgrave Equation to construction sites.
(b) Universal soil loss equation: The Agricultural Research
Service of the U.S. Department of Agriculture has developed the Universal
Soil Loss Equation ' from analyses of vast quantities of data on soil
losses in croplands. This equation takes into account the influence of
the total rainfall energy for a specific area rather than rainfall amount.
The total rainfall energy can be computed for localized areas from exist-
ing U.S. Weather Bureau data. The Universal Equation is:
A = R K LS C P , (6-2)
where A is the average annual soil loss, R is the rainfall factor,
K is a soil-erodibility factor, LS is a slope length and gradient
factor, C is a cropping and management factor, and P is the support-
ing conservation practice, such as terracing, strip cropping, and con-
touring.
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Recently, Wischmeier and coworkers,ft2/ developed a
soil erodibility nomograph for computing K factors for the Universal
Soil Loss Equation for farmland and construction sites. The nomograph
is shown in Figure 3-4 in Section 3.0 of this report.
The reader is referred to Section 4.0 (Agriculture) of
this report and references 47-51 for information on methods of evaluating
the various terms of the Universal Equation as well as the limitations
of prediction with this equation.
The Universal Soil Loss Equation has been recently
adapted by Swerdon and KountzftP-/ for use in predicting soil loss
from highway construction. Meyer^Z./ has summarized the use of the
Universal Soil Loss Equation for predicting the annual erosio.n rates on
construction sites, and for evaluating credibilities with alternative
land management practices. Purdue University, ' under a grant from
the Environmental Protection Agency, is attempting to modify the Universal
Soil Loss Equation to include chemical and mineralogical parameters to
allow better prediction of soil loss from construction activities. Other
studies36,40/ have aiso extended the application of the Universal Soil
Loss Equation to construction areas. The methods require that assumptions
be made relative to the cropping management and erosion control practice
factors and to the extrapolation of the slope length and gradient factors
from previous results to the conditions encountered in construction. They
incorporate the results of recent research-52_' on the soil erodibility
factor for subsoils.
Construction usually exposes soil to rainfall on slopes
steeper than those found in agricultural applications, which results in
greater quantities of runoff at higher velocities. This is especially
true in the case of highway construction, which has been often held
responsible for significant increases in suspended sediment yield in
adjacent streams. Younkin ' reported on the development of an equation
that may be used for computing the suspended sediment load carried by a
stream system during periods of rainfall-induced erosion of disturbed
soils common to highway construction. The prediction equation of Younkin,
based on a graphical multiple regression analysis of 86 sets of data
from the White Deer Creek Valley drainage basin in Pennsylvania, is:
Q8, in metric tons = 0.0092R1-5 [loB A + 0.392]2'45 (3.32)°
(6-3)
Q , in tons = 0.034R1'5 (log A)2'45 (3.0)D ,
S pO.72
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where Qs is the suspended sediment yield at a stream station in
metric tons (tons), A is the area of the exposed surface affected
by the rainfall in hectares (acres), R is a rainfall factor in the
Universal equation in metric tons/hectare/year ' (tons/acre/year),
P is a dimensionless proximity factor, and D is the average depth,
in meters (yards).
The use of the Universal Soil Loss Equation in predicting
the amount of soil erosion at construction sites is demonstrated by the
following example. A road is built near Covington, Kentucky, on a 4.57»
slope and with a 61.6 meter (200 ft) length. The soil is Eden silty
clay, and is bare of vegetation. The parameter values in the soil loss
equation are
R = 394 metric tons/hectare/year (175 tons/acre/year),
K = 0.28 ,
LS = 0.7
C = 1.0
P = 1.0
The calculated erosion rate is
E = (394)(0.28)(0.7)(1.0)(1.0)
= 110 metric tons/hectare/year
(34.4 tons/acre/year)
6.6.3 Methods of data collection: Information required for
quantification of soil erosion and sediment production from construction
sites include the location and area of construction, soil and geologic
conditions, rainfall data, topographic features, hydrologic characteristics,
ground cover condition, as well as suspended sediment level of the surface
water. Such data can be obtained through literature surveys, on-site
inspection, and stream water monitoring.
The following discussion on literature surveys and field surveys
is condensed in great part from "Guidelines for Erosion and Sediment
Control Planning and Implementation," EPA-R2-72-015.
(a) Literature survey: A survey of literature pertaining
to erosion and sediment control at construction sites should include the
use of topographic, geologic, soil, and zoning maps; aerial photographs;
and publications which provide sources of information on physical features
(including topography, soil, geology, hydrology, and rainfall) that relate
to erosion potential of the sites. Inquiries should be made to government
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agencies at the federal, state, county, and municipal levels, and to
private construction companies, for specific information on construction
activities in the area.
Maps and aerial photographs are available from several
governmental sources. An important source are topographic maps of the
U.S. Geological Survey. The quadrangle maps published by the D.S.G.S.
have a scale of 1:24,000 and a contour interval of 6.096 m (20 ft).
These maps are valuable in studying the gross topographic features of
the site.
Other important sources of maps are the state Geological
Surveys. The geologic maps (state and/or county) published by these
organizations display gross topographic features, and show the recognized
and inferred rock outcrop areas of the various geologic units. These
maps provide geologic information related to soil erosion and sediment
production.
County highway, planning, and zoning maps are often avail-
able, and are useful in developing information prior to site evaluation.
Local aerial photographs are usually available at the
local county soil and water conservation district office. These terrain
photos provide many important features of construction sites. Stereo-
scopic pairs of air photos permit the viewing of the area in three
dimensional perspective. As a result, landforms, vegetation features,
hydrologic features, and man-made features are clearly visible.
In addition to the various types of maps, there are several
publications which provide general information on local soil and geologic
conditions. The most useful publications, which are readily accessible
for public use are the County Soil Survey Reports. These reports, pub-
lished by the Soil Conservation Service of the U.S.D.A., contain much
useful information for evaluating the erosion potential of construction
sites. For example, they contain photo mosaics which are superimposed
on soil maps. These photo mosaics which show soil characteristics such
as permeability, grain size gradations, and unified and AASHO soil
classifications, can be used to extract characteristics of soils which
relate to erosion and sediment production. In addition to soil char-
acteristics, the photo mosaics also show the ground slope and major
drainage patterns of the area including a delineation of flood plain
soils and relative locations of roadways, woodlands, and agriculture areas.
The state and county highway departments are also important
sources of soil data, particularly for subsurface information. These
agencies often have records of subsoil and bedrock types, groundwater
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conditions, and various engineering properties of soils and bedrocks
resulting from their roadway and foundation investigations.
In many states the State Geological Survey publishes
water resource bulletins at the county level. These bulletins contain
statistical information on the hydrology of various drainage basins in
the county as well as on the groundwater characteristics of the various
geologic units.
Local rainfall data, and data pertaining to rainfall-
erosivity index used in the Universal Equation or the Musgrave Equation
are available from the Soil Conservation Service or the Weather Bureau.
For example, values of the factor "P" (2-year, 30-min storm) used in the
Musgrave Equation are presented in the Weather Bureau Technical Bulletin
No. 40. For factor "R," which is used in the Modified Musgrave Equation
and the Universal Equation, data are given in the USDA-ARS Agriculture
Handbook No. 2822.=.' for states east of the Rocky Mountains, and in
USDA-SCS Technical Release No. 5ll§/ for the non-orographic rainfall
areas in the west. Separate "R" data for orographic areas in the west
are expected to be made available from SCS soon.
(b) Field survey: The field survey includes a study of
soil surfaces at the development site, and an investigation of the char-
acteristics of local geology, soil, and conditions of streams. If the
construction involves extensive grading, it is also desirable to perform
a subsurface study, to provide information on the geologic soil and ground-
water conditions that influence the erosion hazards of the site.
Soil cover: The soil cover of construction sites is
evaluated as bare ground or protected soil. Bare ground, defined as
nearly totally void of vegetative cover, has a very high erosion poten-
tial. This type of soil cover will require extensive control measures
to prevent erosion and sediment runoff during and after construction.
Protected ground is defined as an area covered with grass,
shrubs, vines, trees, or litter. A dense cover of these materials is
effective in preventing erosion on slopes, swales, and along drainage
ways and impounded waters. Whenever soil erosion is evaluated, any type
of cover, even if it is weeds, is considerably better than exposed earth.
Soil characteristics: The presence of highly erodible
soils is a very critical physical feature, especially if these soils
occur on moderate to steep slopes. It is not always possible for the
layman to recognize a highly erodible soil horizon. It may be masked
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by a stand of vegetative cover or it may exist as a soil horizon beneath
a surface soil of a different character.
Highly erodible soils are usually characterized by a
deficiency of soil particles that have cohesive strength. This cohesive
strength is usually a function of the clay sized (colloidal) fraction of
the soil horizon. However, there is no absolute rule of thumb because
soil characteristics can be variable even within the boundaries of
individual soil mapping units. It is important that the erodibility
of soils be evaluated;if there is any doubt professional assistance
should be requested.
Stream conditions: Streams deserve a very careful evalua-
tion when erosion arid sediment hazards are examined. The streams can
contribute substantially to the sediment load through channel degradation
and bank erosion, and these factors must be taken into consideration in
interpreting sediment concentration data as well as in calculating sedi-
ment yields from construction sites. Several factors contribute to
channel degradation and stream bank erosion: the slope of the stream
bed; the characteristics of soil and rock formations; restrictions in
the channel; the magnitude of slug flow during rainfall or snowmelt;
and vegetative cover on stream banks. Some of these are modified by
activities in the watershed, including construction activities.
6.4.4 Monitoring o£ turbidity and suspended sediment level:
The turbidity and suspended sediment data concentrations of river water
have been monitored at several thousand locations throughout the United
States. For some locations, historical trends are available for periods
in excess of 50 years. Some of these water quality inventories are
maintained by the Environmental Protection Agency, the U.S. Geological
Survey, the Army Corps of Engineers, and state water pollution control
agencies.
When necessary data are not available from existing sources,
local water quality monitoring programs must be established to determine
the extent of pollution caused by construction activities.
A good sampling program is important for obtaining accurate
information to determine the impact of construction activity on suspended
sediment.
Two sampling systems can be considered. In one, the program
is on a short-time basis with sampling locations up- and downstream of the
construction site. This system is particularly useful when the construction
253
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is confined to a small drainage basin, where the whole construction site
can be treated as a contiguous unit. By comparing up- and downstream
data, the impact of the construction activity on the suspended sediment
yields and concentrations can be determined.
When construction activities are spread throughout a
large watershed, the net pollutional effect of total construction can be
determined with sampling stations located downstream of construction sites.
The duration of the sampling period will in this case be extended over
a longer period of time. In this circumstance, the impact of construction
activities on the suspended sediment concentration can be analyzed by
comparing records taken before and after construction starts. Such
comparison should be made on the basis of the same stream-flow rate,
since soil erosion varies with different rainfall intensity and rainfall
amount.
254
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Bases for Action," Washington, D.C. (1969).
2. Ibid., "Fate of Organic Pesticides in the Aquatic Environment,"
Advances in Chemistry Series, 111, Washington, D.C. (1972).
3. American Society of Agricultural Engineers, "Erosion and Sediment
Control on Urban and Construction Sites — An Annotated Bibliography,"
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List for Construction," Draft, Washington, D.C., September 1971.
5. Bailey, T. £., and J. R. Hannum, "Distribution of Pesticides in
California," Journal Sanitary Engineering Div. , ASCE, 93(SA5),
27 (1967). ~~
6. Beasley, R. P., Erosion and Sediment Pollution Control, Iowa State
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Engineering, 4M7) , 50, July 1971.
9. Bloom, S. C., and S. E. Degler, "Pesticides and Pollution," The
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10. Corps of Engineers, "Civil Works Construction Guide Specification
for Environment Protection," Draft, CE-1300, Department of the
Army, Washington, D.C., May 1970.
11. Corps of Engineers, "Specifications for Dam and Appurtenances,
Phase No. 1, Bloomington Lake," Department of the Army, Baltimore
District, Baltimore, Maryland, Sections 2-13, November 9, 1972.
255
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12. Cywin, A., and E. L. Hendricks, "An Overview of USDl's Role in
Sediment Control," Proc. National Conference on Sediment Con-
trol, Washington, B.C., U. S. Department of HUD, September 1969.
13. Environmental Protection Agency, "Regulations for the Acceptance
of Certain Pesticides and Recommended Procedures for the Disposal
and Storage of Pesticides and Pesticide Containers," Federal
Register, 36_, 13,622, May 23, 1973.
14. Environmental Protection Agency, "Water Quality Standards Criteria
Digest," Washington, D.C., August 1972.
15. Federal Power Commission, "Electric Power Transmission and the
Environment," Washington, D.C., November 27, 1970.
16. Forest Service, "Planning Considerations for Winter Sports Resort
Development," U. S. Department of Agriculture in cooperation with
National Ski Areas Association, Washington, D.C. (1973).
17. Gibbs, R. J., "Mechanisms of Trace Metal Transport in Rivers,"
Science, 18£, 71, April 6, 1973.
18. Guy, H. P., "Sediment Problems in Urban Areas," Circular 601E,
Geological Survey, U.S. Department of the Interior, Washington,
D.C. (1970).
19. Guy, H. P., and G. E. Ferguson, "Sediment in Small Reservoirs Due
to Urbanization," Journal Hyd. Div., Proc., ASCE, 8£(HY2) (1962).
20. Hayes, W. A., "Less Pollution With Improved Erosion Control,"
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Michigan, December 8-11, 1970.
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Prevention and Control," Special Report No. 35, National Research
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and Use, "Interim Report," Public Buildings Service, GSA,
Washington, D.C., p. 70, July 1972.
23. Ibid, "Status Report," Public Buildings Service, GSA, Washington,
D.C., p. 39, October 1972.
256
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24. Lin, S., "Nonpoint Rural Sources of Water Pollution," Circular 111,
Illinois State Water Survey, Urbana, Illinois, pp. 1-19 (1972).
25. Mackenthun, K. M., The Practice of Water Pollution Biology,
Federal Water Pollution Control Administration, Washington, D.C.
(1969).
26. McCullough, C. A., and R. R. Nicklen, "Control of Water Pollution
During Dam Construction," Journal of the Sanitary Engineering
Division, ASCE, 97(SA1), 81 (February 1971).
27. Meyer, L. D., "Reducing Sediment Pollution by Erosion Control on
Construction Sites," Seventh American Water Resources Conference,
AWRA, Washington, D.C., October 25-29, 1971.
28. Musgrave, A. W., "The Quantitative Evaluation of Factors in Water
Erosion--A First Approximation," J. of Soil and Water Conservation,
2, 133-138 (1947).
29. Robinson, A. R., "Sediment, Our Greatest Pollutant?", Paper No.
70-701, Winter Meeting, Am. Soc. Agric. Eng., St. Joseph, Michigan,
December 8-11, 1970.
30. Robison, R. R., D. D. Fillis, and S. L. White, "Special Report on
Control of Turbidity During Construction of Teton Dam and Power
and Pumping Plant," U. S. Department of the Interior, Bureau of
Reclamation, Washington, D. C., pp. 1-16, January 1973.
31. Rudd, R. L., "Pesticides and the Living Environment," The University
of Wisconsin Press, Madison (1971).
32. Scheidt, Melvin E., "Environmental Aspects of Highways," Journal of
the Sanitary Engineering Div., ASCE, 9^(SA5), 17, October 1967.
33. Skidmore, E. L., and N. P. Woodruff, "Wind Erosion Forces in the
United States and Their Use in Predicting Soil Loss," Agriculture
Handbook No. 346, ARS-U.S. Department of Agriculture, April 1968.
34. Soil Conservation Service, "Controlling Erosion on Construction
Sites," Agric. Information Bulletin No. 347, U.S. Department of
Agriculture, Washington, D.C., December, 1970.
257
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35. Soil Conservation Service, "Guidelines for the Control of Erosion
and Sediment in Urban Areas of the Northeast," U.S. Department
of Agriculture, Upper Danby, Pennsylvania, 134 pages (1970).
36. Soil Conservation Service, "Procedure for Computing Sheet and Rill
Erosion on Project Areas," Technical Release No. 51, U.S. Depart-
ment of Agriculture, Washington, D.C. (1972).
37. Soil Conservation Service, "Sediment--It's Filling Harbors, Lakes,
and Roadside Ditches," Information Bulletin No. 325, U.S. Depart-
ment of Agriculture, Washington, D.C., December 1967.
38. State of California, "Environmental Impact of Urbanization on the
Foothills and Mountainous Lands of California," Department of
Conservation, Sacramento, California, November 1971.
39. State of Pennsylvania, "Estimating Rainfall-Erosion Soil Losses on
Construction Sites and Similarly Disturbed and Unvegetated Areas
in Pennsylvania," Technical Guide Section II-H, March 1970.
40. Swerdon, P. M., and R. R. Kountz, "Sediment Runoff Control at High-
way Construction Sites, A Guide for Water Quality Protection,"
Engineering Research Bulletin B-108, Pennsylvania State University,
January 1973.
41. Superintendent of Documents, "Soil, Water, and Suburbia," Government
Printing Office, March 1968.
42. The Johns Hopkins University, "Report on Patuxent River Basin,
Maryland," Baltimore, Maryland, June 1966.
43. Thronson, R. E., "Control of Sediments Resulting from Highway
Construction and Land Development," Environmental Protection
Agency, Washington, D.C., September 1971.
44. U.S. Department of Housing and Urban Development, "Proceedings of
the National Conference on Sediment Control," Washington, D.C.,
September 14-16, 1969.
45. U.S. Department of the Interior and the U S. Department of Agri-
culture, "Environmental Criteria for Electric Transmission Systems,"
Superintendent of Documents, GPO, Washington, D.C., October 1970.
258
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46. Vice, R. B., G. E. Ferguson, and H. P. Guy, "Erosion from Suburban
Highway Construction," J. Hyd. Div. , Aroc. , ASCE, 9<4(HY1) , 347
(1968).
47. Wischmeier, W. H., "A Rainfall Erosion Index for a Universal Soil
Loss Equation," Proceedings of the Soil Society of America, 23(3),
246, 4 pages (1950).
48. Wischmeier, W. H,, "Estimating the Cover and Management Factor for
Undisturbed Areas," presented at USDA Sediment Yield Workshop,
Oxford, Mississippi (1972).
49. Wischmeier, W. H., C. B. Johnson, and B. U. Cross, "A Soil Erod-
ibility Nomograph for Farmland and Construction Sites," J. Soil
and Water Conservation, 26, 189, 5 pages (1971).
50. Wischmeier, W. H , and J. V. Mannering, "Relation of Soil Properties
to its Erodibility," Soil Sci. Soc. Am., 33(1), 131-137 (1969).
51. Wischmeier, W. H., and D. D. Smith, "Predicting Rainfall-Erosion
Losses from Cropland East of the Rocky Mountains," USDA-ARS
Agriculture Handbook No. 282, 47 pages (1965).
52. Yorke, T. H., and W. J. Davis, "Effects of Urbanization on Sediment
Transport in Bel Pre Creek Basin, Maryland," Professional Paper
No. 750-B, Geological Survey, U.S. Department of the Interior,
Washington, D.C., p. B218 (1971).
53. Ibid, "Sediment Yields of Urban Construction Sources, Montgomery
County, Maryland," Progress Report, Geological Survey, U.S.
Department of the Interior, Rockville, Maryland (1972).
54. Younkin, L. M., "Effect of Highway Construction on Sediment Loads
in Streams," in "Proceedings of a Conference on Soil Erosion:
Causes and Mechanisms; Prevention and Control," National Science
Foundation, Washington, D.C., January 26, 1973.
259
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7.0 ACKNOWLEDGEMENT S
This study was conducted by personnel of Midwest Research
Institute, assisted by Hittman Associates, Inc.; Dr. Joseph W. Leonard,
Director, Coal Research Bureau, West Virginia University; and
Dr. Rosmarie von Rumker, RvR Associates. Hittman Associates, Inc.,
contributed much of the information on construction; Dr. von Rumker
supplied information on pesticides; and Dr. Leonard consulted with the
project staff on the mining industry. Principal authors of the report
are Dr. S. Y. Chiu, Dr. J. W. Nebgen, Dr. A. Aleti, and Dr. A. D. McElroy
of the Institute staff. Other contributors include Mr. Francis W.
Bennett, Dr. Roy Donahue, Mr. Raymond Mischon, and Mr. E. P. Shea.
Technical direction was provided by Dr. McElroy and Dr. A. E. Vandegrift,
Assistant Director of MRI's Physical Sciences Division.
Mr. Charles P. Vanderlyn, Office of Air and Water Programs,
Environmental Protection Agency, served as Project Officer. The Project
Officer and numerous individuals in public and private organizations
assisted the project staff in the task of collecting information, and
commented constructively on a preliminary draft of the report. The
assistance provided by these individuals and organizations is gratefully
acknowledged.
«U.S. GOVERNMENT PRINTING OFFICE: 1973-546-311/115 1-3
261
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U.S.
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