EPA-660/2-73 035
1974
Environmental Protection Technology Series
Joint Construction
Sediment Control Project
LU
O
Office of Research and Development
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five bread
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
U. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, equipment and
methodology to repair or prevent .environmental
degradation from point and non-point sources of
pollution. This work provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards.
EPA REVIEW NOTICE
This report has been reviewed by the Office of Research and
Development, EPA, and approved for publication. Approval
does not signify that the contents necessarily reflect the
views and policies of the Environmental Protection Agency,
nor does mention of trade names or commercial products consti-
tute endorsement or recommendation for use.
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EPA-660/2-73-035
April 1974
JOINT CONSTRUCTION SEDIMENT CONTROL PROJECT
By
Water Resources Administration
State of Maryland
Annapolis, Maryland
and
Burton C. Becker
Dwight B. Emerson
Michael A. Nawrocki
Contract No. 15030 FMZ
Program Element 1B2042
Project Officer
John J. Mulhern
Pollution Control Analysis Branch
Office of Research and Development
Washington, D.C. 20460
Prepared for
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $2
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ABSTRACT
During the period of this demonstration, a natural and agricultural
region is being converted to an urban community. This project consists
of (1) the implementation, demonstration, and evaluation of erosion con-
trol practices; (2) the construction, operation, and demonstration of the
use of a stormwater retention pond for the control of stormwater pollu-
tion; and (3) the construction, operation, and maintenance of methods
for handling, drying, conditioning, and disposing of sediment. In addi-
tion, a gaging and sampling program was conducted as part of this project
to determine the effects of urbanization on the hydrology and water qual-
ity of natural areas. This project was conducted in the Village of Long
Reach, Columbia, Maryland.
This report ,vas submitted in fulfillment of Grant No. 15030 FMZ by the
Water Resources Administration, State of Maryland, under the partial
sponsorship of the Environmental Protection Agency. Work was com-
pleted as of June 1973.
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CONTENTS
jection Page
I CONCLUSIONS 1
II RECOMMENDATIONS 6
III INTRODUCTION 8
IV EROSION CONTROL DEMONSTRATION 14
V STORM WATER STORAGE AND TREATMENT 44
VI HYDROLOGY AND ECOLOGY STUDIES 61
VII SEDIMENT .AND WATER QUALITY STUDIES 92
VIII REFERENCES 102
IX APPENDICES 103
ill
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FIGURES
1 Ge'ograp location of Demonstration Area 10
2 Demonbi.-- ,n Watershed and Subwatershed
Locations 11
3 Planned Land Development: Village of Long Reach,
Phelps Luck Neighborhood 13
4 Demonstration Watershed and Subwatershed Locations 34
5 Double Gaging Station 36
6 Gaging Station Above Pond 36
7 Gaging Station Below Pond 37
8 Interior of Instrument Shelter at Gaging Stations
Nos. 1 and 2 37
9 Interior of Sampler Shelter at Station No. 3 39
10 Serco Sampler at Station No. 4 39
11 Demonstration Area Dam Site Plan and Profile 45
12 Storm Runoff Hydrograph for Storm of July 29-30, 1971 65
13 Storm Runoff Hydrograph for Storm of August 1-2, 1971 66
14 Storm Runoff Hydrograph for Storm of April 13, 1972 68
15 Map of Demonstration Area With Stream Channel
Cross-Section Locations 69
16 Computer Rainfall Hyetograph for Storm of July 1-2, 1971 73
17 Computer Inlet Hydrograph for Storm of July 1-2, 1971 74
18 Forebay Design 93
19 Conventional Dragline - Dump Truck Operation 96
20 Long Reach Scoop Arrangement 96
age
IV
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TABLES
age
1 Planned Land Development for the Demonstration
Watershed 12
2 Erosion Control Installation and Maintenance Data
(Summer 1971 Price Base) 25
3 Selected Description, Cost, and Application Information
for Chemical Products 26
4 Mulch Description, Cost, and Application Information 27
5 Physical Characteristics of Storm Water Retention Pond
and Watershed 47
6 Reference and Experimental Subwatershed Characteristics
as Related to Storm Runoff Produced 64
7 Pond and Forebay Sediment Removal Costs 97
8 Average Water Quality During Base Flow Conditions 101
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ACKNOWLEDGEMENTS
This final report for the "Joint Construction Sediment Control Project"
was prepared under the joint sponsorship of the U.S. Environmental
Protection Agency and the Water Resources Administration, State of
Maryland, by Hittman Associates, Inc. of Columbia, Maryland. Sin-
cere thanks are extended to Donald J. O'Bryan, Acting Chief, Pollution
Control Analysis Branch, EPA, and John J. Mulhern, Project Officer,
EPA, for their support and guidance throughout the period of basic data
acquisition and document preparation.
Special guidance was provided by Mr. Marshall T. Augustine, Sedimen-
tation Specialist, Water Resources Administration, State of Maryland,
and his participation and assistance in the preparation of this document
is gratefully acknowledged. The limnological consulting services pro-
vided by Mr. William H. Amos and editorial comment and support of
Mr. Albert E. Sanderson, Jr., Coordinator for Research, Water
Resources Administration, State of Maryland, is acknowledged with sin-
cere thanks.
The contributions provided to this program by the Howard Research and
Development Corporation, the developers of Columbia, Maryland, and
the Columbia Parks and Recreation Association, Inc., are also gratefully
acknowledged.
VI
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SECTION I
CONCLUSIONS
1. Detailed planning and schedules for erosion control are depen-
dent upon construction schedules. Unforseen delays can some-
times negate a well-planned erosion control scheme. The pub-
lication "Guidelines for Erosion and Sediment Control Planning
and Implementation" can provide guidance that can minimize
the effect of unscheduled delays.
2. Erosion control practices, products and/or techniques must
be tailored to individual sites and must be based on topography,
soil conditions, construction operations, etc.
3. Planning of the erosion control scheme must anticipate poten-
tial problems, which may be created by future activities. It
must consider such items as the location of future construction
in relation to that already complete, the time lapse involved,
the effective alternative available during the interlude, as well
as the cost of, and benefit from, the installation of selected
techniques.
4. Design and implementation of erosion and sediment control
measures must be somewhat flexible in order to facilitate
decisions made on site. These decisions can only be made by
specialists who understand the construction activities and the
erosion and sediment control activities.
5. Construction of underground utilities must be planned and
coordinated in a manner that will cause, minimal surface dis-
turbance and eliminate repeated disturbance of stabilized areas.
6C Trees that are to be preserved on wooded lots undergoing
development must be carefully selected and then protected from
damage throughout the duration of construction activities.
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7. Stumps should be removed from wooded lots by the use of a
stump cutting device rather than by bulldozing or blasting.
8. Any wood from clearing operations that is not sold for timber
or reserved for fireplace use should be processed by a "wood-
chipper" and the chips should be returned to the lot or removed
to other areas for use in other erosion control programs.
9. The demand for waste glass to produce products currently, on
the market (all glass brick, glass and clay brick, glassphalt,
etc.) far exceeds the supply and the possibility of using waste
glass to make erosion control products is negative.
10. The cost of erosion or sediment production measurements of
individual lots could not be justified. The small watershed
approach must be selected unless nearly unlimited funds for
monitoring are available.
11. Investigations indicate that the use of lanthanide silicates and
rare earth tracers and neutron activation analysis for the
identification of erosion sources and for quantitative evaluation
of soil loss was not warranted.
12. The weirs, rain gages and level recording devices used in this
demonstration have proven to be accurate, reliable, and easy
to maintain.
13. Automatic, point-integrating samplers have serious deficiencies
in their operational characteristics. In addition, the suspended
sediment data they generate are of questionable value since
they are not representative of actual in-stream conditions.
14. The use of "pit" type samplers for bed load investigations in
small streams is useless. Generally, the state-of-the-art of
bed load, swash load, saltation load, etc., measurement is
very primitive.
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15. Comparative performance evaluations between the experimental
and the reference sub water sheds were inconclusive because of
the considerable delays in home construction in both areas.
16. The type of design used for the dam and retention pond is
adequate from astormwater management and sediment trap
standpoint. In addition, its presence in the development was
readily accepted by the residents.
17. During the demonstration, the experimental subwatershed
generally produced less storm runoff, per unit area than the
reference subwatershed. No explanation for the occasional
exception could be determined.
18. Small runoff events generally produce a greater difference in
runoff per unit area between the two subwatersheds than do
larger runoff events.
19. As development progressed in the two subwatersheds, less of
a difference in the runoff yields between the two subwatersheds
resulted.
20. The overall, long-term trend in the main stream channel is
one of channel downcutting in the upper reaches of the stream
and shoaling by deposition or aggradation in the lower reaches.
Continued cutting of the outside banks and deposition at the toe
of meanders as well as general channel widening occurred.
21. The plan implemented for sediment and erosion control during
development in the demonstration area works very well on a
macro scale. Only minor amounts of clay sized particles
escaped the watershed under study due to the large combination
storm water and sediment retention pond.
22. More erosion control and stormwater management techniques
must be implemented in upstream areas and channel reaches
if channel erosion in urbanizing areas is to be kept within
acceptable limits.
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23. The residential population will accept sediment control ponds
especially if they can be converted to aesthetically acceptable
and harmonious use after construction is complete.
24. The lotic environment of the stream has been almost
destroyed due to lack of stability, heavy sedimentation, and
abrasive particle transport: loss of pools and protective
cover presents little chance of natural recovery by former
populations.
25. Stream channel recovery may be possible, in part, if:
. the stream banks are stabilized with vegetation
. pools are reestablished
. sediment transport is greatly reduced
. the stream bottom is stabilized
. runoff containing organic compounds is strictly controlled
. stormwater management practices are implemented to
reduce the volume of periodic surges
. base flow during dry periods can be maintained.
26. The lentic environment of the pond gives the impression of
an ecosystem showing rapid trends toward a natural
succession of life-forms.
27. Based on laboratory tests, it does not appear that chemical
additives will reduce the final moisture content in sediment
drying. However, some polyelectrolytes do improve the
initial dewatering rates.
28. Actual cost figures were higher (ona per cubic yard removed
basis) during the removal of sediment from the forebay and
pond than the cost reviews conducted early in the study had
indicated.
29. The establishment of a grass filter strip around the perimeter
of the conventional sediment drying bed proved to be effective
in removing solids being carried in water draining from the
sediment.
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30. Grass seed germination occurred first on plots of sediment
that were conditioned by the addition of digested sewage
sludge.
31. Grass coverage and density was greater on plots conditioned
with fertilizer (10-10-10) or sewage sludge.
32. Under base flow conditions, little difference in the quality of
discharge water was noted between pond influent and pond
effluent.
33. Alkalinity, hardness, and chloride measurements on samples
collected from the stream and pond remained the same
throughout the demonstration.
34. Nitrite, nitrate, and total phosphate measurements, on
samples collected from the stream and pond increased sig-
nificantly during the course of the demonstration.
35. Based on limited observations, the actual trap efficiencies
during selected storm overflow conditions were generally
higher than those predicted on a theoretical basis.
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SECTION II
RECOMMENDATIONS
Continue operation of all stream and rain gaging stations to refine
the present storm water retention pond evaluation criteria and
develop more definitive evaluation parameters.
Perform similar studies on a number of storm water retention
ponds to establish more detailed design criteria to meet specific
requirements.
Continue gaging of the reference and experimental subwatersheds
in order to fully explore the changes in the hydrologic parameters
which occur when a watershed goes from essentially undeveloped
to urban.
Make further trials of the EPA Storm Water Management Model
when the project watershed is at a more extensive degree of
development.
Continue gaging the demonstration area after development is
complete to gather much needed information regarding runoff
conditions in an urban area.
Continue the ecological monitoring of the pond to determine
what further degradation or recovery it experiences during the
remainder of the development period and into the post development
period.
Conduct a comparative evaluation of other urban runoff models
using, the basic data generated on this project.
Conduct a detailed study to try to determine why the reference
subwatershed occasionally produced less runoff than the
experimental subwatershed.
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Continue the support of further applied research projects in
erosion and sediment control associated with construction
activities.
Conduct research and development of automatic suspended
sediment sampling equipment. Emphasis must be placed on
completely automatic, remote station, depth integrating samplers,
Continue research into methods and/or approaches to the reuse
of sediment removed from sediment basins.
Continue research, via applied research projects, into the
maintenance aspects of sediment and erosion control practices,
devices, methods, etc.
Continue research into the long-term use of sediment basins
for stormwater management, recreational use, etc.
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SECTION III
INTRODUCTION
This project, the "Joint Construction Sediment Control Project, " was
conducted in the Village of Long Reach, Columbia, Maryland. It was
operated by the Water Resources Administration, State of Maryland,
under an Environmental Protection Agency demonstration grant. Hittman
Associates, Inc. , of Columbia, Maryland, was the prime contractor for
this project. Howard Research and Development Corporation, the devel-
opers of Columbia, and the Columbia Parks and Recreation Association,
Inc., a nonprofit corporation representing the community use, partici-
pated in this project.
During the period of this demonstration program, a formerly natural and
agricultural region was partially converted to an urban community. This
project consisted of:
1. The implementation, demonstration, and evaluation of erosion
control practices
2. The construction, operation, and demonstration of the use of
a local storm water retention pond for the control of storm
water pollution
3. The construction, operation, and maintenance of methods for
handling, drying, conditioning, and disposing of sediment
In addition, a gaging and sampling program was conducted as part of
this project to determine the effects of urbanization on the hydrology and
water quality of natural areas.
This demonstration project was generally conducted within a 190-acre
watershed in the Village of Long Reach. A variety of practices were
demonstrated and evaluated in order to develop general criteria and
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guidelines for implementation of storm water pollution and erosion con-
trol techniques. Specifically, it was to:
1. Evaluate the effectiveness and costs of conventional and advanced
methods of erosion control in urban areas (surface landscape
techniques)
2. Evaluate the effectiveness and costs of various methods for the
transport, drying, conditioning, and disposal of sediment
3. Evaluate the effectiveness and acceptability of introducing storm
water and sediment retention ponds in urban communities
The demonstration area is located in the Village of Long Reach, the
fourth of seven proposed villages to be developed within the planned city
of Columbia, Maryland. Located in Howard County, Columbia lies
approximately midway between the metropolitan areas of Washington, D. C
and Baltimore, Maryland. Figure 1 shows the geographic location of
the demonstration area.
In essence, the approximately 190-acre demonstration area encompasses
the watershed of a storm water retention pond constructed in Long Reach.
The general topography consists of rolling hills with a dense, forested
overgrowth following the major stream channels and some of the swales.
Within the demonstration watershed, two similar and adjacent subwater-
sheds were chosen for analysis. On one subwatershed, termed
the reference subwatershed, standard, State-approved methods of ero-
sion control were used, while on the other, termed the experimental
subwatershed, advanced and unique erosion control techniques were
studied. For both subwatersheds, a program of sampling and evaluation
was conducted. Figure 2 shows the location of the reference and experi-
mental subwatersheds within the demonstration area.
At the start of the demonstration, the area was essentially rural in
character. It was originally planned that the village would be almost
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HOWARD COUNTY
MARYLAND
Figure 1. Geographic Location of Demonstration Area
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Q REFERENCE SUB-WATERSHED
© EXPERIMENTAL SUB-WATERSHED
Figure 2. Demonstration Watershed and Subwatershed Locations
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completely developed by the end of the demonstration period. Planned
land development within the vicinity of the demonstration watershed is
shown in Figure 3. As shown, five basic land uses were planned,
including apartment and townhouse developments; single-family, medium-
density housing; single-family, low-density housing; commercial zoning;
and open space. The commercially-zoned property is to be used for the
village and neighborhood centers that include small shops, food stores,
meeting places, and some recreational facilities. Generally, the open
space has been left in its natural state for use as parks, hiking trails,
etc. The exception is the large tract near the center of the village. It
is the site for an elementary school. Table 1 summarizes the planned
land use for the demonstration watershed and for both subwatersheds.
TABLE 1. PLANNED LAND DEVELOPMENT FOR
THE DEMONSTRATION WATERSHED
Demonstration Reference Experimental
Watershed Watershed Watershed
(Acres) (Acres) (Acres)
Single-family,
low-density
Single-family,
medium* density
Apartments and
townhouses
Commercial
Open space
Roads
Total in Columbia
Not in Columbia
Total Watershed
51.7
53. 1
19.0
164. 1
26. 1
190.2
12. 5
6.6
4.0
2.5
25.6
9.2
34.8
24. 2
0.4
3. 7
28. 3
16.9
45. 2
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OPEN SPACE
LOW DENSITY HOUSING
MEDIUM DENSITY HOUSING
APARTMENTS h TOWNHOUSES
COMMERCIAL
INDUSTRIAL
Figure 3. Planned Land Development: Village of Long Reach,
Phelps Luck Neighborhood
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SECTION IV
EROSION CONTROL DEMONSTRATION
GENERAL
Because of the intense interest in sediment and erosion control techniques
and their applicability to recently adopted legislation (Chapter 245 of
the Acts of 1970 - the Statewide Sediment Control Act) this part of the
"Joint Construction Sediment Control Project" was designated as the
"primary" area of concern by the State of Maryland, Water Resources
Administration (formerly Department of Water Resources). Since
sediment is the number one pollutant (volumetric) of the nation's waters,
the EPA was also keenly interested in this phase of the demonstration.
The primary objectives of the Erosion Control Demonstration were
jointly established by these two governmental agencies and stated that
the work was to consist of "the implementation, demonstration, and
evaluation of erosion control practices " (Offer and Acceptance of
Federal Grant for Research and Development, Program Number
15030 FMZ). Specifically, the project was to "demonstrate and
evaluate a variety of practices in order to develop general criteria
and guidelines for implementation of storm water pollution and erosion
control techniques. " In support of this effort, it would be necessary to:
1. Monitor and record the status of residential development
2. Install, apply, and monitor the performance of various
erosion control practices
3. Install and operate sampling equipment
4. Collect samples
5. Conduct surveys of eroded areas and sediment deposits
6. Monitor and record cost and application information
required to implement control of selected practices
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They also recognized an immediate need for the compilation and publi-
cation of data generated during the conduct of this segment of the demon-
stration. Highest priority was assigned to the task of preparing and
presenting a document that would provide the public with information
that could aid in the planning and implementation of sediment and ero-
sion control practices and techniques.
"Guidelines for Erosion and Sediment Control Planning and Implementa-
tion" is that document (Ref. 1). Published as Environmental Protection
Technology series report number EPA-R2-72-015, the "Guidelines" was
released to the public sector by the Office of Research and Monitoring,
U. S. Environmental Protection Agency in August 1972.
The principal purpose of the "Guidelines" is to help those people engaged
in urban construction prevent the uncontrolled movement of soil and the
subsequent damage it causes. The "Guidelines" presents a comprehen-
sive approach to the problem of erosion and sediment control from
beginning of project planning to completion of construction. It provides:
1. A description of how a preliminary site evaluation determines
what potential sediment and erosion control problems exist at
a site being considered for development
2. Guidance for the planning of an effective sediment and erosion
control plan
3. Procedures for the implementation of that plan during operations
In addition, technical information on 42 sediment and erosion control
products, practices, and techniques is contained in four appendices.
A cross-index and a glossary of technical terms used in the document
are also provided.
Since the "Guidelines" is a document of more than 200 pages, data con-
tained in it will not be repeated in this report. It contains application
criteria and should be used as a supplementary reference to this report.
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In addition to these primary charges, the Erosion Control Demonstration
contained several additional tasks. Surveys and evaluations of readily
available sediment sampling equipment were to be conducted. Using the
results of this effort,equipment was to be procured for field installation
and monitoring of sediment production from both small and large areas.
The feasibility of using "tracer techniques">and other, more conventional,
methods of determining soil removal and deposition were also to be
investigated. Those items that showed promise and could be utilized
within the program budget were to be demonstrated. The possible use
of recycled glass bottles for the manufacture of products that could be
used in erosion control work was also to be investigated.
Documentation of airfield work and construction progress was accom-
plished by aerial photographs and repetitive bench mark photography
from numerous locations throughout the demonstration area.
UTILITY CONSTRUCTION
Construction of roads, utilities, and homes in the experimental and
reference subwatersheds was originally scheduled for completion during
the duration of the demonstration project. However, construction
schedules established by the developer throughout the demonstration
watershed were delayed considerably from those originally established.
The delays were especially significant in the experimental subwatershed
and precipitated a shift in emphasis from the monitoring of construction
operations and the application of erosion control measures and techinques
associated with general suburban construction to those specifically
associated with the installation of roads and public utilities, i. e., storm
and sanitary sewers, water, gas, electricity, and telephone, and those
individual home sites that did undergo development. It is noteworthy
that at the end of the first year of operation (June 1971) only 18 lots
were under development in the reference subwatershed and home con-
struction had not yet begun in the experimental subwatershed. At the
end of the 21-month period scheduled for the conduct of the erosion
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control demonstration,a total of only 19 lots had been, or were being,
developed in the reference subwatershed and only five lots were under
development in the experimental subwatershed. The total number of
lots or portions of lots available for development in the reference and
experimental subwatersheds is 61 and 60 respectively. These numbers
convert to percentages of only 31 percent and 8 percent of development
potential initiated or realized during the course of the demonstration
period.
In keeping with the overall Columbia plan, all utilities are subsurface
installation. The schedule delays presented a unique opportunity to
observe and monitor the construction of all utilities in considerable
detail. It has also been possible to observe and treat the erosion con-
trol and sediment production problems associated with utility construc-
tion. The consensus of the technical specialists working in, or acting
as advisors to, the program in erosion and sediment control is very
favorable in that the opportunity to acquire detailed data during the
construction of utilities is very unique, if not an absolute first. It
is also felt that, because of its unique character, this type of data is in
demand and will be readily received and used by those associated with
the environmental stress imposed by construction activities. Data
generated from this experience was used extensively in the "Guidelines. "
Erosion control problems encountered during the installation of utilities
indicate that responsiveness to these problems is much more important
than exhaustive planning. Detailed planning and schedules for erosion
control are dependent upon construction schedules and unforeseen delays
can completely negate a well-planned erosion control scheme. This is
especially true when vegetative practices are involved. Effective treat-
ment requires a "see it today, treat it tomorrow" philosophy. It also
requires that erosion control products and equipment for their application
be available for immediate use.
These observations do not negate the need for planning and scheduling.
They do indicate that some flexibility must be maintained in order that a
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change or delay will not completely negate a well concieved sediment
and erosion control plan. Standard specifications, currently available
for .erosion control work, are often unable to provide a workable solution
to a particular problem. Individual erosion control practices, products,
and/or techniques must be tailored to an individual situation based on
topography, soil, construction operations, etc. The perfect example
is the establishment of an interim vegetative program that will be
destroyed by construction before it can mature to an effective age.
The use of a synthetic product that can give immediate relief to the
problem is clearly indicated in this case.
Planning of the erosion control scheme during utility construction must
anticipate potential problems created by future activities as well as con-
sider real situations created by utility construction that has been com-
pleted. For example, consider the case where storm sewer, sanitary
sewer, and water utility construction is complete and a period of
inactivity is expected before electricity, telephone, and gas are to be
installed. The design of an erosion control scheme must consider such
items as the location of future construction in relation to that already
complete, the time lapse involved, the effective alternatives available
during the interlude, and the cost of, and benefit from,the installation
of selected techniques.
No standards have yet been developed to cope with these situations.
However, three pertinent observations can be made at this time:
(1) Design and implementation of erosion control measures must be
flexible in order to facilitate decisions made on a site-by-site basis;
(2) these decisions must be made by persons knowledgeable in both the
construction and erosion control fields; and (3) scheduling of utility
construction should, wherever possible, consider the following
suggestions:
1. Area disturbed during construction needs to be reduced.
It was observed that 96+ percent of the total area (4.49 acres)
adjacent to the roadway (sidewalk right-of-way and roadway
banks) in the experimental subwatershed was disturbed by
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excavation, spoil pile, material storage, or equipment travel
during utility construction.
2. Construction schedule duration needs to be compressed in
order that the duration of "bare soil" conditions can be
reduced. This can only be achieved through closer cooperation
and coordination of individual utility construction activities.
It should also be noted that the "utilidor" concept, i. e. , more than one
utility is buried in a common trench or conduit, is very desirable from
an erosion and sediment control standpoint. This scheme requires the
disturbance of smaller areas and could eliminate the repetitive distur-
bance of a given area by the separate construction of individual utilities.
HOMESITE CONSTRUCTION ON WOODED LOTS
Many practices, products, and techniques were demonstrated in conjunc-
tion with the development of homesites. The general experience and
data generated during this effort has also been incorporated into the
"Guidelines" and will not be repeated here. However, since much of
the work was conducted in conjunction with the development of wooded
sites, some repetition of the most significant observations is warranted.
Trees to be preserved must be carefully selected. Damaged and/or
diseased specimens on any lot can most economically be removed during
the initial clearing operations. Trees selected for retention must be
protected. They can tolerate only very minor disturbance of the soil
under the canopy and the protection provided must extend out to the
canopy margin (drip line). It is seldom possible, or desirable, to save
trees that are close to home foundations. This is especially true if the
home has a basement. If construction activity encroaches inside the
drip line of trees close to a home, its chances of survival are greatly
reduced. The undesirability of a dead or dying tree in close proximity
to a home comes from the danger of its becoming a "dead fall" during a
windstorm and the potential danger this poses to the structure and its
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inhabitants. It also costs more to remove a tree that is close to a
structure since it is usually removed a piece at a time so that the
adjacent structure will not suffer damage.
Two wooded lots, upon which homes had been,constructed, were selected
for study and implementation of remedial tree removal or treatment.
Both were originally cleared before construction and the remedial work
reported below was required to (1) remove trees whose root systems
were severely damaged during home construction to the extent that they
could not be expected to survive; (2) remove trees that were diseased
or had incurred previous damage and should have been removed during
the original clearing operation; and (3) prune or trim trees that were
slightly damaged but were judged to have a reasonable chance to survive.
Cost data are for March 15, 1972, and are the actual costs of work on the
two lots as performed by a local tree removal specialist. Eight men
were required for a total duration of 12 hours to accomplish the work.
Their effort was allocated as follows:
Tree surgery 2 men
Felling and cutting 2 men
Material removal and cleanup 3 men
Feeding woodchipper 1 man
Following are excerpts from the job description and cost sheets for each
of the two lots.
Description for Lot 1 Take Down & Trim Clean Up
Take down one "Red Oak" tree 50.00 40.00
Take down one "White Oak" tree 85.00 100.00
Take down and clean up nine small trees 185. 00
Take down oak tree near lumber pile 65.00
Dead-wood "Pin Oak" side of house 45.00 20.00
Dead-wood "Pin Oak" back of house 75. 00 35. 00
Dead-wood "Pin Oak" near road 75.00 35.00
Trim Beach tree 50.00 10.00
Total 445.00 425.00
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Description for Lot 2 Trim & Take Down Clean Up
Take down one "Red Oak" close to house $100. 00 $ 25. 00
Take down one "Double tree" 85.00 25.00
Take down one "Hickory tree" 65.00 45.00
Take down one "Oak tree" near street 125.00
Take down seven "Medium trees" 140.00
Take down seven "Small trees" 35.00
Trim "Red Oak" next to house 20.00 15.00
Take down "Red Oak" next to house 50. 00 45. 00
Dead-wood "Oak tree" near street 25.00 15.00
Extra deadwood cleanup 65.00
Total $345.00 $535.. 00
Stumps should be removed.by the use of a stump cutting device rather
than by bulldozer or blasting. The stump cutter disturbs only the tree
stump areas and the chopped wood is then returned to the area that used
to be the stump.
Following is the job description and cost data (April 3, 1972) for stump
removal using a "Stump Cutter" on two lots in the experimental sub-
watershed.
Description for Lot A
Hickory stump side of house $ 35. 00
Double Chestnut Oak stump 20. 00
Oak stump near double stump 20. 00
2- White Oak stumps in back of house 20. 00
Maple stump near road 10.00
2- Gum stumps 20.00
Red Oak stump in front of house 35. 00
Small Red Oak next to driveway 15. 00
Total on stumps $175. 00
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Description for Lot B
Take out stumps on lot, includes taking loader in
to move stumper around over the rough ground.
Total price of taking stumps out $150.00
Cost of hauling loader plus loader time 35. 00
$185.00
Time requirements for stump removal by the "Stump Cutter' are
dependent upon stump diameter, stump height and depth to which stump
is to be removed. Stump parameters encountered during this phase of
the demonstration are as follows:
Depth
Height (below ground)
Diameter (above ground) of Removal Time Required
5 in. 12 in. 4-6 in. 5 minutes
10 in. 12 in. 4-6 in. 15 minutes
15 in. 12 in. 4-6 in. 20 minutes
20 in. 12 in. 4-6 in. 30 minutes
25 in. 12 in. 4-6 in. 45-70 minutes
30 in. 12 in. 4-6 in. 60-90 minutes
In addition, an average time of 15 minutes of setup time is required at
each stump.
There need be no "waste" wood products associated with tree removal.
In temperate climates the disposal of wood cut to fireplace length is
easy and can often be profitable. Any wood not sold for timber or
destined for fireplace use should be processed by a "woodchipper" and
the chips returned to the lot or removed to other areas to be used in
the erosion control program.
More information on the above mentioned subjects is contained in the
"Guidelines. "
22
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PRODUCTS, PRACTICES, AND TECHNIQUES
A total of 45 products, practices, and/or techniques were investigated
during the term of the demonstration project. They were divided into
four major categories for purposes of evaluation and reporting. The
major categories and the individual entries are:
1. Chemical Soil Stabilizers, Mulches, and Mulch Tacks
Aerospray®52 Binder
Aquatain
®Curasol AE
®Curasol AH
DCA-70
Liquid Asphalt
NCI556. 2 L (experimental product - not available
commercially)
Petroset®SB
Plastsoil (small plot demonstration only - not used
in on-going program)
Terra Tack
2. Erosion and Sediment Control Structures
Check Dam
Chutes /Flumes
Diversion Dike
Erosion Check
Fabriform® Erosion Control Mats
Filter Berm
Filter Inlet
Flexible Downdrain
Gabions
Interceptor Dike
Level Spreader
Sandbag Sediment Barriers
Sectional Downdrain
Sediment Retention Basin
Straw Bale Sediment Barriers
23
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3. Fiber Mulches, Mulch Blankets, and Nettings
Excelsior Blanket
Fiber Glass Matting
Glassroot®
Jute Netting
Mulch Blankets
Netting
Plastic Filter Sheet
Sorghum, dehydrated (small plot demonstration only -
not used in on-going program)
Straw or Hay
Wo ode hips
Wood Fiber Mulch
4. Special Erosion and Sediment Control Practices
Construction Coordination
Mulch Anchoring
Pumped Water Management
Roughness and Scarification
Stump Removal
Traffic Control
Tree Protection
Vegetative Filter Strip
Woodland Clearing and Excavation
Technical and product information on all but the experimental or small
plot demonstration products are contained in the appendices attached to
the "Guidelines for Erosion and Sediment Control Planning and
Implementation. "
Only three of the practices listed above were used by the developer in
addition to the routine establishment of vegetation throughout the duration
of the demonstration program. They include sediment retention basins,
interceptor dikes, and filter inlets at storm drain inlets. Installation
and maintenance data are presented in Table 2.
24
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TABLE 2. EROSION CONTROL. INSTALLATION
AND MAINTENANCE DATA (SUMMER 1971 PRICE BASE)
Average
Cost of Maintenance Cost of
Practice Installation Performed Maintenance
Sediment Retention Basin $3200. 00* None $-
>'f >'f
Interceptor Dike 6.00-12.00 None
Filter Inlets 6.60*** Remove sediment 1.75****
after storms
;'i
Average cost to the Howard Research and Development Corp., for
construction of basins in and around the demonstration area.
;u j,
'Built with motor patrol or small dozer in 15-30 minutes - $24/hr.
with operator.
3J£ J^ vU
"20 cubic feet of crushed rock at $0. 2975/cu. ft. = $5. 85 plus
30 minutes of labor time at $3. 50/hr. = $1. 75.
.
30 minutes of labor time at $3. 50/hr. = 1.75.
In addition to the information presented in the "Guidelines" and in Table
2, additional information on some of the newer products is presented
below since some of the Chemical Soil Stabilizers, Mulches, and Mulch
Tacks had not been extensively utilized prior to 1970. Selected descrip-
tive, cost and application information on seven of these products is
presented in Table 3.
Three types of wood fiber or fiber glass mulch were used on various
areas in the demonstration program in addition to those areas that
were stabilized with the conventional wheat straw. Information on
these products, i.e., Glassroot , Hydro Mulch, and Silva-Fiber® is
presented in Table 4.
Detailed cost data are not presented for other products, practices, and
techniques since cost parameters are very dependant on items such as
site conditions, labor, heavy equipment costs, transportation, etc.
25
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tND
OT
TABLE 3. SELECTED DESCRIPTION, COST, AND APPLICATION INFORMATION
FOR CHEMICAL PRODUCTS
Product
Aerospray'^52
Binder
Aquatain
® Curasol AE
® Curasol AH
DCA-70
Petroset® SB
Terra Tack
Raw Material
Cost"
$2. 90 /gallon
2. 75 /gallon
2. 67 /gallon
3. 00 /gall on
2. 50 /gallon
2. 25 /gallon
2. 00 /pound
(packed as powder)
Soil
Stabilizer
Yes
No
Yes
Yes
Yes
Yes
No
Mulch
(on
seeded
areas)
Yes
Yes
Yes
No
Yes
Yes
Yes
Mulch
(in
Hydroseeder
slurry)
No
Yes
Yes
No
Yes
Not tested
Yes
Mulch
Tack
No
No
Yes
Yes
Yes
Yes
Yes
##
General
Manufacturer's
Recomm ended
Application
Rate/Acre
30-45 gallons
130 gallons
30-65 gallons
30-45 gallons
30-45 gallons
•A. o-vU
~f "f *T»
15-20 pounds
(mulch tack)
50 pounds
(scnl stabllizer>
Rates determined from simple formula or nomograph supplied by manufacturer.
Application rates consider: (1) desired depth of penetration, (2) soil particle size, (3) abrasive force
to protect against, and (4) topography.
Small volume (50 gaUon/pound) lots, Summer 1971.
*
Detailed application criteria available from manufacturer.
-------
TABLE 4. MULCH DESCRIPTION, COST,AND APPLICATION INFORMATION
Manufacturer's
Recommended
Application Application Equipment Mulch Tack Required
Product Raw Material Cost Rate Required to Prevent Wind Erosion
Glassroot® $15.40/35 Ib. pkg. 35 lb/4000-5400 Glassroot® dispensing None
sq. ft. (280-380 kit and 15 cfm air
Ib/acre) compressor
Hydro Mulch 3.50/50 Ib. bag 1000-1500 Ib/ Hydroseeder None
acre
Silva-Fiber® 3. 75 /50 Ib. bag 1000-1400 Ib/ Hydroseeder None
acre
Wheat straw 48.00/Ton 1 1/2-2 ton/acre Straw Blower Chemical Mulch tack
or liquid asphalt
*
Price Base — summer 1971.
-------
A part of this segment of the Erosion Control Demonstration was the
conduct of an investigation to determine the feasibility of using recycled
waste glass to produce an erosion control product/s. This seemed
especially pertinent, since several erosion control products made of
fiber glass were on the market.
The possible utilization of recycled glass in erosion control was discussed
with representatives of the Glass Container Manufacturers Institute. The
potential market for glass products in the erosion control field, the
economics of producing recycled products, and the required physical
characteristics of the products were discussed.
The conclusions drawn from this investigation must be regarded as
generally negative because the need for glass to produce products that
are currently on the market (all glass brick, glass and clay brick,
glass phalt, etc.) far exceeds the supply of used glass. It was further
determined that, if all of the used glass in existence could be made
available for reuse in these products, the supply would still fall short
of the demand.
Monitoring and Sampling Investigations
One of the major charges of the demonstration program was to try and
determine the comparative effectiveness of an advanced or accelerated
erosion control program to a routine program. It was for this reason
that "reference" and "experimental" subwatersheds were selected and
delineated (see Section III).
The first effort toward the accomplishment of this goal was a review
of the measurement techniques, both conventional and novel, that might
be utilized on this project. It was recognized that the evaluation and
comparison of the performance of the various erosion control practices
would require techniques that will measure quantitatively the effectiveness
of soil retention. Conversely, the amount of soil lost during individual
storms and over the periods during which the practice is in effect might
28
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be used to measure the effectiveness of the practice. The measurement
techniques must, therefore, be capable of measuring the loss of soil
during individual storms or over periods of time.
Consideration was also given to the utility of measuring sediment produc-
tion at individual locations within the subwatersheds. This approach was
abandoned because there was no encouragement that "individual small
plot" evaluation schemes could be maintained during the development
activities. The "applied research project" intent also dictated that any
monitoring scheme be harmonious with the development and construction
activities scheduled for implementation during this time period and that
demonstration project activities not be an unusual or costly burden to
the developer and builders involved.
It was also recognized that stream gaging facilities were going to be
installed to provide basic data for other major areas of investigation.
Four installations were planned and a double stream gage was to be
constructed at the confluence of the streams from the reference and
experimental subwatersheds.
With these considerations in mind, the investigation of various physical
measurement and monitoring techniques was conducted. Summary
information on the various techniques is listed below.
(1) Conventional Survey Techniques. Topographic maps
would not be sufficiently accurate to measure soil losses
for overall areas. Even if feasible, they would require
an excessive amount of effort. For these reasons,
conventional survey techniques can only be used for
estimating the quantities of material deposited in
sediment traps, the storm retention pond, stream
channels, etc.
(2) Laser Leveling. Consideration was given to the use of
the newly developed laser level as a method of direct
measurement of soil loss and deposition. Accuracy
-------
of one-thousandths of a foot is obtained with a level rod
and an audible light detector. However, it would still be
necessary to use conventional surveying techniqes to
provide horizontal control, and therefore was not
recommended.
(3) Aerial Photographic Mapping. Although it was recognized
that detailed topographic maps can be prepared from aerial
photos taken at low altitudes, their use is subject to the
same limitations as conventional topographic mapping.
(4) Aerial Stockpile Inventory Technique. A variation of
aerial topographic mapping has been used to inventory
stockpiles of coal, aggregate, sand, etc. The accuracy
and cost of this type of survey precluded its use on this
demonstration project.
(5) Automatic Samplers. Several automatic samplers are
commercially available for collecting water and sediment
samples at intervals. They use either a pump or a vacuum
to collect the samples, and a clock is used to control the
sampling intervals. The vacuum samplers normally use
24 bottles, and the pumped samplers have up to 145 bottles.
Sampling with both types of samplers can be initiated by
a simple stream stage sensor.
(6) U.S. Single-Stage Suspended-Sediment Sampler. An
extremely simple automatic sampler has been developed
for use in areas where observers are not available. It
consists of a sample container stoppered with two inverted
"U" tubes. The lower "U" tube is the sample intake; the
upper intake is the air exhaust. The sampler operates
on a siphon principle. As designed, it collects a composite
sample.
The use of clustered single-stage samplers designed to
operate at various levels or in sequence by controlling the
air vents by a simple rainfall control was also considered.
30
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(7) Radioisotope Sediment Concentration Sensors. A nuclear
direct sensing device for suspended sediment concentra-
tion has been developed by the U. S. Atomic Energy
Commission. This device uses a small amount of
cadmium-109 to determine the density of the water
sediment mixture. A concurrent electrical conductivity
measurement is used to correct for solute concentrations.
This device was not judged to be applicable to the monitoring
requirements of this project.
(8) Grab Samples and Field Analysis Techniques. To
supplement automated sampling techniques, grap samples
can provide needed data to evaluate local effects and/or
special situations.
(9) Bedload Samplers. In addition to measuring the quanti-
ties of waterborne sediment, it would also be desirable to
measure the quantity and type of sediment moved along
the bottoms of major streams. Bedload samplers are
available for use in this capacity. However, past
experience (ARS, U. S. Army, USGS, etc.,) with bedload
samplers was not encouraging since problems associated with
the collection of representative samples and the operation
and/or maintenance of these devices during periods of
high volume flow are considerable. Then, too, computation
of bedload amounts and parameters of delivery to points
downstream is a very "unexact" science.
During the course of the preliminary investigations conducted during
the preparation of the grant application, it was recognized that an
alternative to physical measurements and sampling techniques might be
the use of tracer techniques to quantitatively measure the loss of soil
from selected areas.
The evaluation of the possible use of lanthanide silicates and rare
earth tracers and neutron activation analysis as a method for
31
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the identification of sources of erosion and for quantitatively evaluating
the amount of soil loss was conducted concurrently with the investigation
of the physical measurement and monitoring techniques. In the literature
search, no directly comparable application of this technique was found.
Even though the use of tracers and activation analysis appears to be a
feasible method for monitoring and measuring soil loss, basic research
work would be required to develop practical methods for the application
of this technique to soil erosion and transport. For qualitative measure-
ments, techniques are required for uniformly applying the tracer material
to the soil particles in such a way as to not change the erosion and
transport characteristics of the materials. In the few applications of
this technique, the tracer and base materials were specially prepared
and placed. No attempts had been made to apply tracers to materials
in place.
With respect to using different tracers to identify sources of pollution,
a number of possibilities exist. Further investigation indicated that it
might be possible to use activation analysis techniques to discriminate
between very dilute mixtures of compounds containing beryllium, boron,
carbon, fluorine, rare earths and lanthanide, and other compounds.
However, experimental work involving irradiation of a number of
samples would be required to screen the possible tracer materials
and to determine their detectability in the presence of the activated
materials normally present in soils. Based on these investigations, it
was concluded that the work required to apply these techniques would
be beyond the scope of the present project and the possibility of
obtaining useful information would be limited.
Monitoring and Sampling Scheme
Using the information generated from these investigations a gaging
and sampling scheme was selected that (1) could be expected to meet
the requirements of all major work areas of the demonstration project;
(2) could be compatible with the construction scheduled for the area;
(3) was available using "off-the-shelf" equipment and extant technology; and
32
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(4) showed reasonable promise that similar installations could be used
to monitor runoff, erosion, and sediment parameters in support of
future requirements in the research or enforcement areas.
The scheme selected for demonstration utilizes three rain gages and
four completely automatic stream gaging and water sampling installa-
tions. Locations are shown on the aerial photograph of the demonstra-
tion area (Figure 4).
The three permanent rain gaging stations utilize weighing-bucket type,
continuous recording gages. Two of the gages are Belfort Instrument
Company products utilizing spring-wound clock drives and ink pen
recorders. The Belfort gages were originally equipped with gears
which provided for one chart revolution every eight days. With this
gear arrangement, rainfall intensities could be estimated every 15
minutes. Midway in the project, the Belfort gears were changed to
provide one chart revolution every 24 hours. This enabled rainfall
intensities to be determined every five minutes. This more accurate
determination enabled a better sensitivity analysis to be conducted
between rainfall intensity and the resultant runoff. The third rain gage
is a Fisher-Porter punch tape model powered by a 7-1/2 volt dry cell.
Data is automatically punched on a tape at 5 minute intervals in 1/10
of an inch of rain increments.
Two of the stream gaging and sampling stations were constructed at
the junction of the tributaries draining the reference and experimental
subwatersheds. They were located so that differences in the runoff
and suspended solids produced in the experimental subwatershed, where
advanced erosion control practices were applied, could be compared to
the reference subwatershed, where only minimal practices were
required. Two other gaging and sampling stations were established
immediately upstream and immediately downstream from the four-acre
pond.
The tandem stream gages (farthest upstream) (Figure 5) are precali-
brated, broadcrested, V-notch weirs developed and tested by the U. S.
Department of Agriculture. The concrete weir caps have 2:1 side slopes
33
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ice Subwaterahed
2 Experimental Subwaterahed
3 Rain gage Locations
4 Stream Gage & Sampling Locations
5 Forebay Location (under construction)
Figure 4. Demonstration Watershed and
Subwatershed Locations
34
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and were poured and formed directly on steel sheet piles driven a
minimum of six feet below the elevation of the stream channel. Earth
berms extend from the end of the weir caps to the limit of the calculated
50-year, post-development floodplain.
The stilling wells and shelters contain both the sediment monitoring
equipment and a Stevens Duplex Water-Level Recorder Type 2A35,
which can simultaneously measure and record the water levels going
over weirs 1 and 2.
Station No. 3 (Figure 6), just above the pond and forebay, is a weir
similar to those at stations 1 and 2, except the side slopes of the
weir cap are at 3:1. This station is also served by a Stevens Type A35
water level recorder.
Station No. 4 (Figure 7), below the pond, uses a sharp-crested, com-
pound, 90 V-notch and rectangular weir as a control section. The
V-notch is 10 inches high and the rectangular section is 2-1/2 feet
high by 6 feet wide. The damping effect of the principal spillway
facilitates the use of this small installation. The stilling well is
equipped with a Belfort portable liquid level recorder.
When necessary, additional stream gaging is performed using a
Gurley pygmy current meter. To date, this method has been used
primarily to check the calibration of the permanently installed weirs.
An automatic water sampling station is located at each of the four per-
manent stream gaging sites. The samples collected from these auto-
matic stations were supplemented by depth integrated hand samples.
At sites 1 and 2 (Figure 8), the sampling equipment is housed in a
combined instrumentation and stilling well shelter. Approximately
13 feet upstream from each weir, the intake from a one-quarter
horsepower pump provides sample water which flows through a turbidi-
meter and then through a fluidic sample bottle rack which periodically
diverts the flow into a sample bottle. The turbidimeters are equipped
with Rustrak recorders as well as visual observation equipment.
During the storm events, the fluidic samplers were programmed to
35
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Figure 5. Double Gaging Station
Figure 6. Gaging Station Above Pond
-------
Figure 7. Gaging Station Below Pond
Figure 8. Interior of Instrument Shelter at
Gaging Stations Nos. 1 and 2
37
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sample every half-hour. A mercury switch automatically starts
each pump and turbidimeter recorder at a given water stage and
provides a cutoff after the stage falls below the predetermined level.
The automatic sediment monitoring equipment at site 3 (Figure 9)
(upstream from the pond) consists of a PS-67 pumping sampler. The
intake for the sampler is located in the stream, some 15 feet upstream
from the weir. The pumping sampler is fed by a one-quarter horse-
power pump which utilizes a 36 volt DC power supply. An automatic
switch activates the sampler upon a sufficient rise in stream water
level and stops it when the stage falls below the set level. The sampler
can be set to take samples at virtually any time increment. During the
field demonstration, it was set to sample every 15 minutes when
activated.
The automatic sampling equipment at site 4 (Figure 10), below the
pond, is a Serco, single-stage vacuum sampler. A switch activates
the sampler upon a sufficient rise in stream level and 24 continuous
samples are then taken at equal specified time intervals.
The primary purpose of the gaging, monitoring, and sampling program
was to establish storm runoff volumes and gross sediment yields. The
storm runoff is, in turn, related to the intensity and duration of the
rainfall, land use, and ambient field conditions. As the area becomes
more developed, the total volume of runoff for a given storm would,
naturally, increase due to the larger amount of impervious area.
Sediment volumes should, however, decrease as the area becomes
stabilized.
In addition to the above mentioned equipment, four Mulhoffer type pit
samplers were constructed for testing and evaluation in the stream
channels. Two U. S. DH-48, depth-integrating, suspended-sediment
samplers were purchased for use to supplement the time-integrated
samples that were collected by the automatic sampling devices.
Four units of six single-stage samplers were fabricated for testing
and potential use in the collection of samples at individual sediment
38
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Figure 9. Interior of Sampler Shelter at Station No. 3
• / ; / -
Figure 10. Serco Sampler at Station No. 4
39
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retention basins selected for special study and analysis.
Monitoring and Sampling Analyses and Results
Equipment Performance Evaluation. The three broad-crested weirs,
the compound weir, and the stage recording equipment has been operated
throughout the duration of the project without any problems. Maintenance
requirements involve chart changes, inking of pens, and the removal
of sediment from the area immediately upstream from the V-notch
weirs. Pen and chart maintenance can be scheduled. The cleanout of
sediment must be accomplished after each storm and sometimes under
base flow conditions to maintain the calibration and accuracy of the
weirs. Failure to remove sediment buildup causes the weirs to act
as flumes and their calibration curves are not applicable under these
conditions. No cleanout was required at the compound weir because
almost no sediment escaped the pond.
Only routine maintenance was required to keep the rain gages operating
in a satisfactory manner. The addition of antifreeze to the collection
buckets was required during the snow and freezing rain season.
Some rather severe problems were encountered with some of the
automatic sampling and monitoring equipment. The recording turbidi-
meters produced no useful data. This was due to the fact that suspended
solids concentration in the runoff quickly went beyond the 1000 JTU
maximum of the instruments. This possibility was recognized before
they were installed, but it was felt they could provide valuable data
after the construction activities were complete and the area had become
somewhat stabilized from an erosion and sediment control standpoint.
However, development did not proceed as originally anticipated and no
opportunity was provided for a fair evaluation of the equipment or the
date that it could produce.
Of the three types of automatic samplers, the bottle racks using "fluidic"
switching devices (P. A. Freeman Assocs. ) were the most dependable
and provided the most trouble-free operation. It did malfunction
occasionally when a small twig with a critical length became lodged in
40
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the system. This occasional malfunction was not judged to be severe.
The PS-67 pumping sampler was often unable to cope with the high
concentrations of suspended solids to which it was subjected. The
major problem was caused by the deposition of sediment in the backflush
holding tank. Because the runoff often had suspended solids concentra-
tions in excess of 20, 000 ppm, and because this water was held for 15
minutes at a time in the backflush tank, gravity sedimentation would often
render the unit inoperable due to the fouling (by sediment) of the float
devices in the backflush tank.
Sustained problems were experienced with the spring-wound timing
device and the vacuum-operated remote starting device on the vacuum
sampler. Five different clock mechanisms were required during the
demonstration project. In addition, the remote starting device could
not be depended upon to activate the sampler after it had been in the
field for more than 24 hours. It needs to be stated, however, that the
sampler itself performed in a satisfactory manner when it was activated
by hand.
All of the automatic samplers have a severe limitation in that they are
point-integrating (pick up samples from a fixed location in the stream)
devices. When the samples that they collected were compared to
simultaneously acquired depth-integrated samples (U. S. DH-48), there
was very little correlation or basis for comparison. This relationship
(or nonrelationship) was experienced on every occasion. Therefore,
the computation of suspended sediment load, gross erosion, etc., based
on the data collected by the automatic equipment is speculative at best.
In the judgment of the scientists and engineers working on the demon-
stration project, it cannot be used in scientific computations. For these
reasons, intensive and immediate research and development is required
to develop an automatic, depth-integrating sampler than can be used in
remote facilities.
No useful information was derived from the "pit type" bedload samplers.
When placed in the stream so that the top of the sampler was flush with
41
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the stream bed, one was buried to a depth from which it could not be
retrieved without machiner. At other times, the samplers would be
filled by sediment moved into the samplers by the baseflow of the
stream. These devices were then abandoned.
The single-stage samplers operated satisfactorily until they were put
in the field. There, they were quickly destroyed by heavy equipment
travel, burial, or vandalism.
Subwatershed Comparative Evaluations. The comparative performance
evaluations to be conducted between the experimental and reference
subwatersheds were, at best, inconclusive. Three major factors con-
tribute to this inconclusive evaluation. They are:
(a) The considerable delays in home construction in the
experimental and reference subwatersheds. The fact
that only 31 percent and 8 percent of the development
potential was initiated or realized during the evaluation
period renders any comparative analyses useless. Even
though great quantities of both qualitative and quantitative
information were generated, the direct comparison of the
effectiveness of advanced erosion control techniques cannot
be accomplished when only 31 and 8 percent of the areas
to be compared can be integrated into the evaluation.
(b) The inability of point-integrating sampling equipment to
collect representative samples of suspended solids being
generated on the areas to be compared.
(c) The total lack of comparability between the point-integrated
samples collected by the automatic equipment and the
depth-integrated samples collected simultaneously by hand.
It should be recognized however, that these deficiencies are not truly
negative; they do emphatically indicate that the state-of-the-art has a
long way to go before reliable, definitive data can be generated from
remote, automatic sediment sampling stations.
jiediment Retention Basin Analyses. One of the areas of interest in this
demonstration was to see if information could be acquired regarding the
42
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trap efficiency of small (less than 1/4 acre) sediment retention basins.
Five of these small basins were selected for study at various times
throughout the term of the demonstration project. A summary of the
problems encountered in the use of single-stage sampler for this type
of field investigation follows.
In Case No. 1, a basin was constructed in the reference subwatershed
to provide protection over the fall and winter until home construction
could be resumed in the spring. It did not function at all during this
period since the topography of the site was not modified to bring the
sediment-laden runoff into the basin. Runoff moved around both ends
of the structure.
Case No. 2 was a small basin in an adjacent subwatershed. There was
no defined channel entering the basin. This resulted in almost sheet
flow movement of runoff into the basin and the single-stage samplers
deployed in this area did not operate since the runoff depth was never
great enough to operate the samplers. The bank of six single-stage
samplers installed to collect water moving out of the principal spillway
was stolen.
In Case No. 3, a piece of heavy equipment ran over the sampler before
it had a chance to function.
The sampler deployed in Case No. 4 was buried under a spoil pile
before it had an opportunity to operate.
Case No. 5 involved the establishment of a detailed topographic survey
of a sediment retention basin installed to remove sediment from runoff
generated on a townhouse development site. It was planned to collect
depth-integrated hand samples to establish the general quality of water
moving into the structure. Resurvey after each runoff event would
determine the volume of sediment trapped and it was hoped that trap
efficiency information would be forthcoming. However, the builder
used most of the basin area as a stockpile for surplus earth and no data
were generated.
These attempts, then, did not generate any data that could be used to
refine the trap efficiency curves, formulas, etc. , that are extant.
43
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SECTION V
STORMWATER STORAGE AND TREATMENT
STORMWATER STORAGE
Facility Description
At the downstream terminus of the demonstration watershed, a lake was
constructed to act as a combination sediment trap and storm water man-
agement device. The lake was impounded by constructing an earth-fill
dam with an impervious clay core across the main stream channel.
Some shaping was then done to the stream valley bottom and sides to
obtain the finished pond configuration.
The principal spillway is a drop inlet type structure of corrugated metal
pipe having a 42-inch riser in the pond and a 24-inch pipe through the
dam. The riser is fitted with an antivortex device. A drawdown device,
consisting of a 10-inch horizontal pipe with a 15-inch perforated riser,
is attached to the bottom of the principal spillway so that the pond can
be completely drained if necessary. A turf-covered emergency spill-
way has been constructed on the west abutment to provide an escape
route for storms whose runoffs are above the design capacity of the
principal spillway. Figure 11 shows the basic plan and profile of the
stormwater retention pond site.
During the course of this demonstration project, the hydraulic perfor-
mance characteristics of the pond were monitored with respect to effi-
ciency as a storm water management device. Stream gaging and
sampling stations numbers 3 and 4 (Figures 6 and 7) monitored the water
quantity and quality entering and leaving the pond. Cross sections of
the pond bottom were surveyed quarterly. Operating records of the
drawdown device valve openings and closings were kept in order to
attempt an analysis of the effect of operating procedure on the pond's
efficiency as a stormwater management device. In addition, the
44
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•Wilt
r^V HteBgil.iunlplii.tBC. I
IP —=^_-— I
Figure 11. Demonstration Area Dam Site
Plan and Profile
45
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quarterly airphoto coverage kept track of the changes to the surface
characteristics of the pond area and its watershed.
Table 5 shows some of the physical characteristics of the pond and its
watershed at the start of and toward the end of the monitoring program
for this demonstration project. The slight decrease in surface area was
caused by minor grading and filling which was done around the edge of
the pond in connection with the construction of a lakeside townhouse
development. The dramatic decrease in storage volume is a direct
result of sediment runoff due to construction activity. This was not
unexpected since the pond also served as the primary sediment trap for
its upstream drainage area. The slight change in the watershed area is
due to the additional area over the original watershed boundaries which
is serviced by storm sewers which empty into the main stream channel
of the pond watershed. In Howard County, separate storm sewers
empty into the natural stream channels. Hence, the storm sewer drain-
age boundaries generally follow the watershed boundaries. However,
slight deviations between the natural watershed and the storm sewer
service boundaries usually occur for the convenience of street layout.
This situation is reflected in the slight increase in watershed area
shown in Table 5.
Performance Evaluation
Quantitative evaluation of the hydraulic performance of such a storm
water retention pond under actual field conditions is difficult at best,
especially in the short period of time available under this program.
Approximately one year of good gaging records were acquired. During
this time, storms of varying rainfall intensity and duration occurred.
To complicate the problem further, the requirements were that the pond
be operated and evaluated with the water level at different prestorm
levels.
To date, little consideration has been given to quantitatively evaluating
the performance efficiency of storm water management devices. The
46
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TABLE 5. PHYSICAL CHARACTERISTICS
OF STORM WATER RETENTION POND AND WATERSHED
Characteristic
9
Surface area, ft"
acres
3
Volume, ft
acre-ft
Average depth, ft
Total watershed area, acres
Date
August 1970
162, 000
3. 72
610, 200
14. 0
3. 8
190. 2
April 1972
159, 000
3.65
513, 400
11.8
3. 2
195.0
Percent
Change
-2
-16
-16
+2
first problem encountered is one of determining on what basis such
devices should be evaluated. The resolution of this problem depends
upon variables such as:
(1) The local hydrologic and meteorolo^ic parameters
(2) The relationship between the degree of protection
desired for given rainfall recurrence frequencies
and cost
(3) The overall intended purpose of the device
(4) Its relationship to other stormwater management
devices in the same or adjacent watersheds
(5) The degree of stormwater retention or retardation
required
(6) The overall purpose and goals of the stormwater
management program
As a beginning, two rather simple parameters which can be used to
evaluate any stormwater management device would be its efficiency in
reducing the peak runoff from any given storm event and its ability to
delay the delivery of this peak storm runoff to downstream areas. The
evaluation of these two parameters, whether singly or in combination,
might be considered a rather simplistic approach to a complex problem,
47
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However, most stormwater management programs to date are geared
toward both reducing the peak flows and retarding the delivery of this
peak to downstream areas. Also, data on these parameters are usually
the most readily available and are the easiest to obtain. Therefore, it
was to these two parameters that the analyses were addressed.
Table A-1 in Appendix A contains the raw data used in the performance
evaluation of the pond when the water level was at normal riser elevation
at the start of the storm. This tabulation includes all storms which
deposited at least one-half inch of total rainfall in the watershed, as
well as a. number of lesser storms. It might be noted that all the storms
recorded when the pond was at full capacity had return frequencies of
less than one year, based on local intensity-duration-frequency curves.
In order to assess the impact which the various hydrologic and meteor-
ologic parameters have on the operating characteristics of the pond
when it is at full capacity, statistical analyses, including correlation
and regression analyses, were performed on the collected data. The
independent hydrologic and meteorologic parameters which were tested
for significance include the total rainfall,average rainfall intensity,
storm duration, peak inflow, and the elapsed time between the peak
inflow and the peak outflow. As a measure of pond performance, three
separate indicators were tested for significance with the above indepen-
dent variables. The three pond performance indicators chosen were:
(1) Elapsed time between the peak inflow and outflow
(2) Percent difference in peak outflow versus peak
inflow as defined by the equation:
°« - I
D = —£ 2 x 100 Equation (1)
P
where:
D , = percent difference between outflow and
inflow, percent
O = peak outflow
P
I = peak inflow
P
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(3) Peak throughflow as defined by the relationship:
O
T = -j-E x 100 Equation (2)
P
where:
T = peak throughflow, percent
and the remaining symbols are as defined previously
Table A-2 in Appendix A contains the data bank of the independent and
dependent variables used in the statistical analyses.
During the final regression analyses, both linear and exponential models
were developed and analyzed, using as many observations (storms) for
the variables as the completeness of the data bank permitted. The
relationship selected for each pond performance characteristic was the
one which was judged to produce the closest fit to the collected data.
Of the two measures of the retention efficiency of the pond (the percent
difference in peak outflow versus inflow and the peak throughflow), the
peak throughflow was found to be more closely correlated with the hydro-
logic and meteorologic parameters tested. The relationship which was
found to best describe this retention parameter of the project pond is:
T = -28.9 + 144R Equation (3)
where:
R = total rainfall for storm event, inches
The correlation coefficient for the above relationship is 0. 897 for the
21 observations (storms) used.
No significant relationship could be found between the retardance char-
acteristics of the storm water retention pond, as measured by the
elapsed time between the peak inflow and outflow, and the dependent
variables tested.
49
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Statistical analysis was also attempted of the hydrologic and meteor-
ologic data collected when the pond level was below normal riser eleva-
tion at the start of a storm. Table A-3 in Appendix A presents the basic
data collected under this task. Because of the wide variability in the
data and the short-term record available, no specific relationships or
significant correlations could be found between the pond retention and
retardance characteristics and the basic hydrologic and meteorologic
data.
Discussion
It was found that, at least for storms with return frequencies of less
than one year, a simple relationship exists for predicting the retention
efficiency of the project storm water retention pond. The relationship,
reported as Equation (3), shows that the peak throughflow for a given
storm event is positively and quite significantly correlated with the total
storm rainfall. Other independent variables tested did not show any sig-
nificant degree of correlation with the pond retention characteristics.
The variability and short-term nature of the data, however, preclude
any extensive testing or refinement of this relationship at this time. In
all probability, it is doubtful whether this exact relationship will hold
for other storm water retention ponds built on watersheds with different
characteristics and to different specifications. However, the analyses
performed are a good starting point for future research into the reten-
tion characteristics of storm water management ponds.
The difficulty with developing exact expressions which describe the
operating characteristics of such ponds in the field lies in the intrinsic
nature of natural hydrologic systems. Factors which produce variances
in the data include:
(1) The watershed area which drains directly tothe pond or to the
pond outfall gaging station (No. 4). Of the total demonstration
watershed, the area draining directly tothe pond and to gaging
station No. 4, and the area of the pond itself, comprise roughly
eight percent of the total drainage area. This means that the runoff
50
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contributed by this eight percent of the watershed is gaged
by station No. 4, but not by station No. 3. The effect of
this can be seen in the tables in Appendix A, especially for
small storms and when the pond is operating with the water
level below normal riser elevation. The direct pond drain-
age area contributes to a higher and sooner peak outflow
than if the pond were isolated from any direct runoff or rainfall.
(2) Plow over the emergency spillway causes a discontinuity in
the retention and retardation characteristics of the pond.
During a storm, when the water elevation in the pond reaches
the level where the turf-covered emergency spillway begins
to flow, more water is delivered in a shorter period of time
to gaging station No. 4 than if the normal overflow riser
had carried the entire flow. In essence, once this level
is reached, the retention and retardation efficiency of the
pond is reduced. Because of the short period of hydrologic
record available, no quantitative data coiild be gathered
on this point. However, it appears that the demonstration
pond emergency spillway begins to accept overflow whenever
the return interval for the rainfall event approaches one
year.
This study was performed on a single storm water retention pond. The
obvious extension of this study would be to:
(1) Continue gaging the study pond to refine the present
evaluation criteria and develop more definitive evalu-
ation parameters
(2) Perform similar studies on a number of storm water
retention ponds to establish more detailed design
criteria to meet specific requirements
Both of these types of studies could define the effects of varying water-
shed slopes, direct pond drainage, spillway capacity designs, etc., on
the retention and retardation of actual ponds if sufficient long-term
51
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records are available. Then designs might be formulated which meet
the specific requirements of any storm water management plan.
Design Criteria
Through the study of the project storm water retention pond, certain
basic design criteria for other storm water retention ponds can be
established. The present pond is designed according to U.S. Department
of Agriculture, Soil Conservation Service criteria. The drawdown device
is manually controlled.
Such a design is entirely acceptable for a storm water retention pond.
Based on the experience acquired from the operation of the project
retention pond, some minor refinements in the outlet design could be
made to increase the pond's efficiency as a storm water management
device. Perforation of the upper section of the normal outfall riser
would create more storm water detention, as the accumulated water
would release slowly through the perforations until the top of the riser
is reached. Then, the normal drop inlet spillway would also begin to
discharge storm flow. In addition, an emergency spillway, such as the
one presently installed in the project pond, would provide an escape
route for the occasional large storm.
The inclusion of perforations in the upper part of the normal overflow
riser would result in a greater fluctuation in the pond water level
elevation between base and storm flows than if the pond were continually
operated at normal riser elevation. Such a situation should be taken into
account if development is planned in the vicinity of the pond.
STORM WATER TREATMENT
Methods for the treatment of storm water before its release from the
pond were investigated. The purpose of this was to determine if a
water quality significantly higher than would normally be released from
the pond could be economically achieved. If the preliminary analyses
52
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indicated that such a feasibility existed, the selected treatment system(s)
would then be demonstrated.
The preliminary investigations narrowed the type of treatment down to
two basic methods. One involved the use of an inclined tube settler at
the outfall to the pond and the other was the addition of polyelectrolytes
either separately or in combination with the tube settler. The inclined
tube settler had not been previously used on storm water runoff. Poly-
electrolytes, on the other hand, have been used previously on storm
water; for example, at Lake Needwood in Montgomery County, Maryland
(Ref. 2).
An analysis of the trap efficiency of the combined pond and forebay sys-
tem concluded that water leaving the pond would have suspended solids
concentrations generally less than 100 mg/4. This analysis was later
verified during the course of the demonstration project by actual field
data. Discussions with manufacturers of inclined tube settlers revealed
that the removal efficiency of inclined tube settlers is greatly reduced
at concentrations of less than 100 mg/4. Consequently, the idea of
installing such a device was abandoned since it would not economically
add materially to the trap efficiency of the pond.
Previously, the use of poyelectrolytes has improved settling of the
suspended solids in storm flows into lakes (Ref. 2). At low concentra-
tions, it has been necessary to also add ferric salts to economically
obtain settling, even withpolyelectrolytes. Based on these facts and the
computed excellent natural trap efficiency of the pond and forebay system,
the addition of polyelectrolytes was also rejected on the basis that their
use would not contribute to a significant increase in pond outflow water
quality.
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PUBLIC ACCEPTANCE AND FLOODPLAIN UTILIZATION SURVEYS
In conjunction with the storm water aspects of this demonstration program,
the Columbia Parks and Recreation Association, Inc., a nonprofit
corporation responsible for the development and maintenance of open
space in Columbia, conducted a survey of the residents of the Village
of Long Reach. Generally, their survey was designed to gather opinions
and suggestions in three major areas. First, they requested suggestions
as to how the residents would like to see the area adjacent to the lake
and the floodplain upstream developed for recreation. Secondly, they
asked the residents how they were currently utilizing the lake and flood-
plain areas (the construction activities have not been completed and
only minor recreation development had been accomplished). Their
third major interest was concerned with the basic desirability of a
four-acre pond and the effect of this pond on real estate, aesthetic and
recreational values.
One hundred fifty questionnaires were prepared for distribution. The
Village Board of Long Reach assumed the responsibility for the distri-
bution of the forms to the residents. Addressed and stamped envelopes
were also included for the return of the completed forms.
The questionnaire consisted of 16 questions and it was estimated that
they would be completed by interested residents in approximately
15 minutes.
Of the 150 questionnaires distributed, 27 were returned to the Columbia
Parks and Recreation Association. The 18 percent return of question-
naires was judged to be a very good response to the questionnaire survey.
54
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The questions and responses that are pertinent to the demonstration
program are listed below.
Because of the qualitative nature of many of the questions,the comments
onthe responses are presented below. Interpretations and conclusions
can then be formulated by the reader without the possibility of compi-
lation prejudices being inserted during the preparation of this report.
Question:
Are you aware that a research project is being conducted
in the Long Reach drainage area upstream from Tamar Drive?
Yes - 12 No-15
Question:
Are you aware that sediment has been removed from the
Hittman Pond at Tamar Drive?
Yes- 9 No-18
Question:
Did this sediment removal impose any degree of hardship
and if so, how?
No- 26
No Answer or Blank — 1
Comments:
1. It still seems to be quite dirty
2. Except for eyesore
Question:
As a resident, what comments can you make regarding the
sediment removal at the Hittman Pond.
No Answer or Blank — 17
Comments:
1. It was carried out with the utmost efficiency & with
little or no inconvenience to the residents of Long Reach.
55
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Comments (continued):
2. We have lived here six weeks and have not seen any work
being done at the pond.
3. Excess sediment in the pond is a danger to anyone accidently
falling in & a potential "Killer" to any fish or plants growing
in the pond.
4. I approve.
5. I know that sedimentation leads to eventual eutrophication
and that removal of sediment was probably necessary to
maintain the pond. Eventually I would think the pond
would fill in completely because of construction runoff.
6. If the sediment is removed & replaced by stocking the pond
with fish it would be an added attraction to Long Reach.
7. The removal must in some way be beneficial if the Columbia
Association and Long Reach Village Board are sponsoring
the project.
8. Probably a good idea to make the pond more useable for
boating and fishing.
9. I don't feel that the pond will be free of the large amount
of sediment until construction is complete and the open
space is fixed up.
10. I feel the removal of sediment made the Hittman Pond
cleaner & more desirable area to picnic in.
Question:
Do you feel that the Lake's existence enhances property
values adjacent to and Village wide?
Yes - 22 No - 4
No Answer or Blank — 1
Comments:
1. Very much so.
56
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Comments (continued):
2. As evidence to this fact, builders charge a premium for
lots adjacent to the lake.
3. The presence of the pond improves our community generally
and enhances property values.
4. Even though it and the surrounding area does not look good.
5. Unless it is allowed to become an eyesore and health hazard
through lack of maintenance.
6. Not necessarily. (Accompanies a "no" answer)
7. Most definitely. (Accompanies a "yes" answer)
8. I feel it enhances property adjacent to it right now.
Question:
Have you used this area for any recreational activities and
if so, how?
Yes - 16 No - 11
Comments:
1. Picnic — tadpole collecting — children play there.
2. Bird watching — hiking.
3. Just walks
4. Picnics and passive recreational purposes
5. Walking, exploring woods, bicycling, etc.
6. Riding & walking the trail along the feeder stream &
skipping stones with the kids & walking the adjacent fields.
Significantly, contemplating the two springs that have
been left to deteriorate near the big trees.
7. I pushed a bike around it twice.
I with the children sailed toy sail boats (sic). The area
is not capable of supporting any recreational activities
because of the condition of the ground — weeds, rocks,
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Comments (continued):
7. very uneven ground, trash, cement piles — its worse
than a cow pasture.
8. Walks & bike rides.
9. Picnics.
10. Picnic.
11. I tried out my fly-rod a few times, but never caught any
fish. I would like to try out a small sail boat on the pond
next summer.
12. We have had a few picnics down there and my sons enjoy
playing in the stream under the bridge although we haven't
been down there since the hurricane rains polluted the
streams & lake.
13. To look at and enjoy the natural beauty.
14. Our family has had several picnics by the pond, we also
find it a very pleasant area for walking which we do
every day. We also hope the pond will be stocked for
fishing.
15. We bicycle to the area & sit there for a rest. Hope to
picnic there next spring & summer if the weeds in the
area are cut regularly.
16. Bike path.
Question:
What kinds of recreation might you suggest in and around
the Lake?
Comments:
1. Tot-lot. Picnic tables. Is it possible to spray for bugs
during the spring & summer months
2. Picnic, fishing, skating.
3. Boating.
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Comments (continued):
4. Long Reach needs teen and adult recreation facilities.
Nobody wants them anywhere. I think the park might donate
part of its land to basketball courts, tennis or some such
activity.
5. Band concerts, picnic areas, boating?
6. No answer at this time.
7. Picnic Area.
8. Foot paths, sitting areas & open grass areas for
unstructured play.
9. To be stocked with fish. Would not like to see a concession
operated at the lake — whether C. A. (Columbia Assn.) and/or
H. R.D. (Howard Research and Development Corp.), or any
other private enterprise!
10. I think something could be done with the springs — restored
spring house, for example.
11. Fishing, Picnic.
12. Mall 'city1 basketball courts (sic). Good area to teach
children boat safety. Also good for children with small
boats to use area for docking.
13. Picnicing, a restful spot. Fishing for kids.
14. If you can clean it up, swimming.
15. Fishing.
16. Picnic tables - benches - Bar-B-Q Pits, Trash cans.
17. Picnic facilities with adequate trash containers & signs
warning against littering! Fishing, sail boating - both
oriented toward children.
18. Boating.
19. Picnics, bicycle path, etc.
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Comments (continued):
20. Boating, fishing, ice skating, picnics.
21. Fishing, primarily, if not exclusively.
22. Boating, fishing, picnic tables, maybe a playground
(a small one).
23. I understand plans are to stock the pond with fish. This
is a good idea & we are in favor of it. Small boats such
as canoes, or tiny sail boats would not be objectionable.
24. A. fishing B. Model boat contests C. Just an area where
life may be found D. Picnicing (tadpoles, etc.)
25. Picnic Area — stock with fish so children can fish there.
26. Picnicing, boating (row boats) maybe fishing. A rock
climbing and sand area made as natural as possible for
smaller children would be an asset.
27. Fishing, ice skating.
Because of the general subjective nature of the survey, the small number
of surveyed units, and the returned questionnaires, quantitative eval-
uation is not warranted . However, some conclusions and observations
can be made. It can be safely reported that the physical process of the
removal of sediment from the pond did not impose any degree of hard-
ship on the residents of the Village of Long Reach. These same residents
indicate that the presence of the four-acre pond in their neighborhood
did enhance property values and that they desired to see the area remain
as "natural" as possible and that recreational development should be
oriented toward family activities, such as picnicing, enjoying nature,
etc., and children's activities.
Raw data are included so that readers of this report may consider or
use it in light of their own experience and/or requirements.
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SECTION VI
HYDROLOGY AND ECOLOGY STUDIES
HYDROLOGY
The hydrology investigations under this project can be divided into
three general categories:
1. Hydrology of urbanizing areas. The gaging stations described
in Section IV were utilized to study the changes in the surface
water hydrology brought about as a watershed goes from a
completely natural state to a fully developed urban area.
2. Stream channel morphology studies. Cross sections were
surveyed at eight different locations along the main stream
channel and reference subwatershed tributary. These sections
were resurveyed quarterly to determine what changes, if any,
occurred in the channel configuration during the various phases
of construction.
3. Application of the EPA Storm Water Management Model (Ref. 2).
Originally, this computer model was to be applied three times
utilizing data from the watershed while it was in different stages
of development. The calculated results were to be compared to
actual gaged data. The purpose of this study was to verify the
model and to test its applicability to watersheds which support
various degrees of urbanization.
Hydrology of urbanizing areas
A total of twelve months of gaging records were acquired during the
life of this project. This is not a long time, hydrologically speaking.
However, this time span does include a record of the area from the
time rough grading for the roads was finished up until approximately
40 percent of the area was developed at the project termination date.
61
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Gages at the termini of the reference and experimental subwatersheds
provided sharp contrasts in how runoff was generated and subsequently
transported in a subwatershed. Land use in the reference subwatershed
(see Figure 3) will consist predominately of medium and low density
housing and open space school sites upon completion of development.
Storm sewei c -'rain the streets of this subwatershed directly into the
natural stream channel. The experimental subwatershed will consist
entirely of low density housing when development is complete. In contrast,
however, this subwatershed is completely storm sewered. The runoff from
the streets flows into storm sewers which collect the water and transport
it by pipe directly tothe main stream channel of the subwatershed at the ter-
minus of the experimental subwatershed. The stream gaging station for the
experimental subwatershed is located directly downstream from this
main storm sewer outfall for the system.
The stream draining the reference subwatershed goes dry at the gaging
station during the summer months of a dry year. This occurred, for
example, during midsummer of 1970. Gaging station No. 2, on the
other hand, should rarely record no flow since this subwatershed
contains numerous springs and seeps which provide an almost continuous
base flow.
In order to compare the reference and experimental watersheds on an
equal basis, the base flows were subtracted from the storm runoffs and
the runoffs for the two watersheds for the recorded storms were then
normalized with respect to area. That is, from the standard discharge
versus time hydrograph, a new, discharge-minus-base flow-per-unit -
area versus time hydrograph was plotted for each station. Since the
average slopes of the two watersheds are approximately equal, this
normalization procedure reduces the number of variables which could
produce a difference in runoff (or water yield) from each watershed.
When this is done, the following conclusions can be drawn:
(1) Throughout the term of the demonstration project the
experimental subwatershed generally produced less
62
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storm runoff per unit area than the reference subwatershed.
This is to be expected since the experimental subwatershed's
natural ground cover is almost 100 percent forest while the
reference subwatershed has a large quantity of open field.
The experimental subwatershed is now completely storm
sewered. That is, the natural stream channels have all
been replaced by buried concrete storm sewers. The
outfall to this storm sewer system is immediately upstream
of gaging station No. 2. On the other hand, the storm
sewers in the reference subwatershed empty into the
natural stream channels. However, the reference sub-
watershed is subject to more intense development.
Table 6 summarizes some of these characteristics
of the two subwatersheds as related to their effects on the
storm runoff yield per unit area.
(2) Smaller runoff events generally produce a greater difference
in runoff per unit area between the two subwatersheds than
do larger runoff events, although exceptions do occur as
in any natural system. Figures 12 and 13 illustrate
this difference. In Figure 12, the peak storm runoff
(total runoff minus base flow) per acre for the reference
subwatershed is almost twice that for the experimental
subwatershed. Figure 13 shows a larger storm and its
corresponding effect on the runoff yields per unit area of
the two subwatersheds. The storms in Figures 12 and
13 ocurred within a few days of each other and thus
the subwatersheds were in the same stage of development.
In Figure 13. (the larger storm), the difference in runoff
(minus base flow) per acre is much less than for the smaller
storm (Figure 12. These two illustrative hydrographs
are typical of the results obtained from most other storms.
(3) As development progressed in the two subwatersheds, less
of a difference in the runoff yields between the two
63
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TABLE 6. REFERENCE AND EXPERIMENTAL SUBWATERSHED CHARACTERISTICS
AS RELATED TO STORM RUNOFF PRODUCED
Characteristic
Natural ground
cover
Reference Subwatershed
Description
60% open field, 40%
wooded
Experimental Subwatershed
Description
95% wooded, 5% open field
Storm sewers Storm sewers empty into No natural stream channels,
Development
Average slope
of ground
natural stream channel.
Medium and low density
housing. Approximately
20% of area devoted to
school site, including
parking lot.
Approximately 4%
completely storm sewered.
All low density housing.
Approximately 4%
Subwatershed with greater
storm runoff
per unit area
as a result of
characteristic
Reference
Experimental
Reference
Equal
-------
J Denotes trace of rainfall
03
Cn
° .04-1
e I
. 02 -
.01 -
Reference Subwatershed
- - Experimental Subwatershed
50 100 150 200 250 300 350 400 450 500 550 600
Figure 12. Storm Runoff Hydrograph for Storm of July 29-30, 1971
-------
O5
Experimental Subwatershed
50
T
100
150 200 250 300 350
400 450 500
Time, min.
600 650
T~
700
~r
750
800
-T
850
900
13. Stor-m Runoff Hydr-ograph for- Storm of August 1-2, 1971
-------
sub water sheds resulted. Figure 14 illustrates this
point. This storm occurred toward the end of the
demonstration project when more development had taken
place in the two subwatersheds. Here, the closeness
between the storm runoff yields per unit area for the
two subwatersheds is apparent. This trend was observed
as construction proceeded in the subwatersheds. Both
large and small storms generally produced less of a
difference in yield between the two subwatersheds.
The above preliminary conclusions can be drawn even though develop-
ment is not yet complete within the project area. No change in other
hydrologic parameters such as the response and lag time could be
discerned for either subwatershed during the course of development.
This is, perhaps, due to the fact that urbanization was not yet complete
in the subwatersheds as the project drew to a close. Continued gaging
of this area is thus recommended in order to fully explore the changes
in the hydrologic parameters which occur when a watershed goes from
essentially undeveloped to urban.
Stream Channel Morphology
Bench.marks were established and initial cross sections were surveyed
at eight locations along the main stream channel of the demonstration
watershed in October 1970. This time corresponded to the completion
of rough grading of the major roads. No other development had occurred
in the watershed. The sections were then resurveyed on a quarterly
basis to determine the changes which a natural stream channel under-
goes as the land use in a watershed goes from a predominately natural
state to one of moderate urbanization. Figure 15 shows the locations
of these eight stream channel cross sections. Appendix B contains the
cross sections at these eight locations which illustrate the observed
stream channel changes.
67
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CT3
CO
0.2 -
0. 15-
0, 1 -
0.05-
0. 2 -
§ 0.1
K
£
o
CO
I Denotes trace of rainfall
Reference Subwatershed
Experimental Subwatershed
50 100 150
200 250 300 350 400 450 500 550
Time, min.
600 650 700 750
Figure 14. Storm Runoff Hydrograph for Storm of April 13, 1972
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OPEN SPACE
LOW DENSITY HOUSING
MEDIUM DENSITY HOUSING
APARTMENTS » TOWNHOUSES
COMMERCIAL
INDUSTRIAL
Figure 15. Map of Demonstration Area with
Stream Channel Cross Section Locations
69
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The cross sections clearly illustrate the already familiar changes which
take place in a stream as a watershed undergoes urbanization. No
startling new or radically different changes were observed. Rather,
the data obtained documented previously reported changes in stream
channel cross section and alignment which occur during construction
activities. The overall, long-term trend is one of channel downcutting
in the upper reaches of the stream and deposition or aggradation in the
lower reaches. The continued cutting of the outside banks and deposition
at the toe of meanders was also observed, as was general channel
widening due to increased runoff.
ShorMerm variations in the channel cross sections were observed which
did not reflect the long-term trends. In fact, these short-term variations
sometimes were directly opposed to the general long-term trend. These
shorter term cycles are a function of the variability of individual storm
runoff events, and local erosion and sediment deposition activity caused
*
by the degree and type of construction activity nearby. Such short-term
variations are illustrated at Sections L and M on the upper reaches of
the stream (see Appendix B).
The long-term trend over the 18 months of record at Section L is
unmistakedly toward a wider and deeper channel. Some of the interim
cross sections, however, show channels shallower than the initial
channel in an undisturbed watershed. This brief aggradation phase
corresponds to the period when the land surface of the watershed was
most disturbed by construction activity. The cross sections in April
and July 1971 reflect this interim trend. After this period, as the
different phases of development were completed and the land was once
again stabilized, the long-term cycle of degradation of the stream
channel, due to increased runoff from the additional impervious area
in the watershed, continued.
Section M also exhibited such a shorMerm variation in its general
degrading trend. First, aggradation occurred as the land was denuded
by local construction activity and erosion increased. Then, downcutting
predominated as storm runoff increased upon completion of storm sewer
70
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construction. Stabilization of the channel at its final elevation and
configuration was only accomplished through use of a concrete lining
which connects into a culvert under High Tor Hill.
In the lower reaches of the stream, including Sections F, G, and M, the
oftentimes excessive deposition can be attributed to both the greater
amount of construction activity downstream as well as the general
flattening of the streambed gradient downstream of Section I. In addition,
the storm water retention pond and its accompaning forebay serve as
excellent preservers of the stream bed bottom elevation in this area.
All three stream gaging weirs and their accompanying downstream
(R)
Fabriform^ protection were also observed to function as excellent
local grade control structures.
Section H, established at the bend of a rather sharp meander, further
illustrates the natural process of channel realignment and cross section
adjustment inherent in any stream whose watershed is undergoing drastic
land use changes. Here, the outside (west bank) of the meander
continues to actively erode as storm water flows increase due to the
increased impervious area in the watershed and the installation of
storm sewers.
From Section I to points upstream, the characteristic geomorphic process
is one of degradation rather than aggradation of the channel bottom. This
corresponds to an increase in the channel slope upstream of Section H.
The steeper slope coupled with the increased storm water runoff from
developed areas produces the consequent observed downcutting of the
channel.
This study indicates that, on a macro scale the plan implemented for
sediment and erosion control during development in this portion of the
Village of Long Reach works very well. Little sediment is deposited
downstream of the watershed under study due to the large combination
storm water and sediment retention pond. More work needs to be done
on a micro scale, i. e., upstream of the pond, however, if the stream
71
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channels in such areas are to he preserved in a natural state. Both
comprehensive storm water management and local erosion control
programs are needed to preserve the configuration of the stream
channel and prevent future flooding problems. Although the stream
channel studied may be quite small in comparison to channels in
urban areas which presently cause problems, this study nevertheless
dramatically illustrates the causes and effects which construction
activity has on a previously undisturbed watershed.
Application of the EPA Storm Water Management Model
The EPA Storm Water Management Model is basically a tool developed
to aid in predicting the amount of runoff and pollutants delivered from
given rainfall events in a completely urban area. During the course
of this project, three major runs of the Model were completed. A
number of minor runs were also made as input deficiencies were found
and corrected.
Because of the low degree of urbanization prevalent in the demonstration
project watershed throughout the project and the discontinuous storm
sewer system, the applicability of the Storm Water Management Model
could not be fully tested. Nevertheless, actual field data was input into
the model in order to try to discern its sensitivity to the various
watershed parameters in small and largely undeveloped watersheds.
The EXECUTIVE and RUNOFF Blocks were primarily used during these
analyses. When a^ watershed parameter was not known or could not be
measured to any great degree of accuracy, the program was left to
choose its own built-in default values.
Reasonable results were obtained from the RUNOFF Block even with
the low degree of urbanization present. Figures 16 and 17 show
the hyetograph and the overland flow hydrograph for one of the subbasins
in the experimental subwatershed for the storm of July 1 to July 2, 1971.
The subbasin shown comprises 2. 14 acres near the downstream terminus
of the experimental subwatershed. Results such as shown are typical of
those received and appear reasonable for the area.
72
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-3
CO
1
I
I
1
1
1
1
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1
I
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r
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Figure 16. Computer Rainfall Hyetograph for Storm of July 1-2, 1971
-------
NO
— IN
0 .002 1
1
1
1
1
i
I
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1
1
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Figure 17. Computer Inlet Hydrograph for Storm of July 1-2, 1971
24. b
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The TRANSPORT Block of the program was also studied for possible
testing. However, the emptying of the storm sewers from the various
subbasins directly into the natural stream channels made direct com-
parison with gaged data impossible in most cases. One computer run
utilizing the TRANSPORT Block was attempted for the complete experi-
mental subwatershed when no urbanization had yet been accomplished
in the subwatershed. Some preliminary runoffs were obtained at
selected points in the subwatershed; however, a complete comparison
with actual gaging records at the terminus of the experimental subwater-
shed could not be done. The EPA Storm Water Management Model was
used on very small watersheds, i. e. , on the order of a few acres, and
in a largely undeveloped area. Thus, a number of peculiarities were
discovered which do not normally show up when the model is more suit-
ably used on larger, completely urbanized areas. These include non-
acceptance by the Model of zero percent imperviousness values in the
input watershed data. This is easily corrected by inputting a very small
number which is essentially zero, such as 0. 01. Tabular printouts sup-
plied in the RUNOFF Block for the computed quantity and quality param-
eters usually show zero (0) values for small watersheds. This is due to
the fact that the parameters are formulated to be printed only to the
hundredth decimal place and naturally, for small watersheds, most of
these parameters are measured in very small quantities. This can be
changed by simply changing the FORMAT specifications for RUNOFF
Block output when small watersheds are being analyzed.
It is recommended that further trials of the EPA Storm Water Manage-
ment Model be made when the project watershed is at a more extensive
degree of development. This would require that adequate gaging records
be kept and that construction activity be monitored on a continuous basis.
However, it is anticipated that only the experimental subwatershed will
be able to be extensively analyzed by the Model because of the discontin-
uous nature of the storm sewer system throughout the rest of the demon-
stration watershed. Use of the experimental subwatershed could thus
provide a check only on the Model's accuracy for a small watershed in
a low density housing area.
75
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Stream Channel and Floodplain Ecology Studies
In this part of the demonstration project,the changes in the ecology of
the stream channel and floodplain associated with urbanization were
monitored. This monitoring was accomplished by periodic visits to a
number of observation sites located throughout the watershed, including
points along the main stream channel above the storage pond, points
within the storage pond and its forebay, and one point along the main
stream channel below the pond.
At each of these points observations were made of the physical appear-
ance and any noticeable changes in the floodplain and stream channel
were recorded. Changes in or loss of arboreal species, vegetative
cover, and aquatic species were noted. These studies were designed
to be of a qualitative nature and were to document the presence of
common indicators or nuisance species which accompany degradation
of water quality or increasing unsuitability of the environment. The
diversity of species was used as a relative indicator of the health of the
stream and pond system.
The initial survey was conducted in July of 1970 at the start of the
demonstration program. It was a cursory survey without sample
collection, count, or analysis and was intended to establish a rudi-
mentary baseline to which subsequent surveys could be compared.
The surveys of June and September 1971, May and November 1972,
were more formal. The initial survey was conducted by one investigator
and the subsequent four were conducted by another, equally well
qualified scientist.
Following is a listing prepared from the initial survey of the fauna
found on the undersides of small stones and boulders that were abundantly
present in the shallow rapids of the streams. Indicators of clean water
include:
(1) Tube building caddis fly larvae
(2) Net building caddis fly larvae
(3) Mayfly nymphs
76
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(4) Planaria
(5) Crayfish
(6) Hellgrammites
(7) Snails and snail egg masses
In addition, leeches were observed associated with mud deposits and
chironomus midge larvae were found on some slimy surfaces. The
chironomus midge larvae usually increase with increased organic
pollution.
Brown and tan colored diatom films are indicators of clean water and
were observed on stones. A rise in the phosphate content of the water
would be indicated by the presence of coppery blue-green algal films
on the rocks. Water striders, diving beetles, and water boatmen
were observed on films in the water. Rusty colored diatom films were
found on aquatic grasses and plants.
Horsefly larvae, dragonfly larvae, and bloodworms are mud dwelling
organisms and were observed at various locations. The horsefly
larvae were found associated with both clean and rich muds. The
dragonfly larvae were usually associated with clean muds, while the
bloodworms were noted where there was heavy organic pollution.
Four forms of floating algae were observed. Filamentous green algae
(Spirogyra) and Hydrodictyon inhabited the pond and are indicators of
clean water. StigeocIonium, also a clean water indicator, was found
in the flowing water.
For purposes of identification in the four subsequent surveys, UPPER
STREAM shall refer to the northerly upper branch which is located
in the reference subwatershed (Figure 2 ). The easterly branch was
not surveyed. LOWER STREAM shall refer to that portion of the stream
from the intersection of the two upper branches to the forebay. POND
shall refer to the storm retention pond. SPILLWAY STREAM shall
refer to the outflow below the dam.
77
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Not all stations were sampled every time in precisely the same fashion.
For example, conditions fluctuated so widely at stations along the
lower stream that different locations, over approximately 50 meters,
were selected on each occasion. The pond transect was not run in
exactly the same line or identical distance since a boat was not used
each time, nor were the marking rods always present.
While certain physical and chemical parameters were monitored at
the time of each survey, there was no attempt to run complete
chemical analyses.
As a result of these and other inequalities, data presented here are
primarily qualitative. On the other hand, the structure of certain
biotic associations, even the presence (or absence) of specific life-
forms, does much to indicate the state of health of an aquatic ecosystem.
At the time the primary stream and pond were seen in the second study,
serious degradation had already set in. What few normal biota were
found occurred only in the upper reaches of the Upper Stream, but
these too disappeared prior to the third and fourth surveys.
A conclusion, which will be reiterated later, is that when the stream-
banks have been stabilized, reducing excessive transport of particulate
matter, the stream— even with an increase in carrying capacity—has
the potential of becoming well-colonized by a variety of lotic organisms.
The'association of these organisms, or species composition, would
indicate the general health, or lack of health, of the stream. But with
a thoroughly unstable stream bed (as now exists) that is subject to
scouring, excessive sedimentation and flushing rates that may increase
by a factor' often, there are no opportunities for indicator organisms
of any sort to become established. Some of the same conditions
prevail in the pond as well, but here the biota are already well estab-
lished. When fine particulate materials and colloids depart, the pond
has an excellent chance of becoming a productive and attractive body
of water.
78
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Note: Organisms in the following sections are rated by
relative abundance as abundant, very common,
common, uncommon, rare, based on counts made
in both field and laboratory. There was no attempt
to relate large, visible forms to microscopic orga-
nisms in this scale.
Stream. The stream has suffered continuous degradation over the
period it has been observed. It was very nearly abiotic at the last
survey. Early in the study, the Upper Stream retained vestiges of its
original plant and animal associations, but now it is almost indistin-
guishable from the severely damaged Lower Stream. The condition of
both streams is due almost entirely to a lack of stability, with accom-
panying sedimentation and abrasive particle transport. Originally it
supported a normal coastal plain association of organisms: aquatic,
marsh, and moist bank plants, and animals characteristic of both
saturated soil and open flowing waters, riffles, and pools. While some
of the more mobile animal organisms are still present along the stream
banks (red-backed salamander, grass frog) or within the substrate
(oligochaetes), little remains of the once-flourishing aquatic insect
population, liverworts, mosses, fluviatile algae, rooted aquatics,
or even diatom films. In one stretch of over 100 meters, only a single
damaged rooted aquatic (Typha) was found in the last survey (November
1972).
Despite severe instability, dissolved oxygen values have consistently
appeared favorable. Nutrient load, which could result in eutrophication
in a stable stream bed, has not appeared marked at the time of sampling,
although it undoubtedly occurs with flush-off from new lawns.
While the Lower Stream was nearly destitute of any significant life-
forms at the beginning of the survey, the Upper Stream at first still
retained a few that are characteristic of the region. Typical of neuston
in such streams was the small, broad-shouldered water strider
(Rhagovelia) congregating near small riffle areas. Since their food
consists of smaller aquatic insects, worms, and other invertebrates,
79
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either on or below the surface, it is assumed there were sufficient
quantities of these to sustain the water strider population.
A few small fishes appeared at some distance and were not collected;
they resembled dace. The most apparent vertebrates were grass frogs
(Rana pipiens) along the banks, and juvenile salamanders (Plethodon sp.)
under stones in quiet reaches of the stream. Motile epifaunal forms
consisted of isopods (Asellus sp.) which were common, and an occa-
sional crayfish (Orconectes virilis). Mud chimneys were found in
associated wet floodplain areas, indicating the chimney crayfish
(Cambarus diogenes). The motile insects included stonefly nymphs
(unidentified) which were common, mayfly nymphs and subimagoes:
a total of three species of immature mayflies, one of which (Potamanthus
sp.) was very common.
Attached (sessile) or infanual life-forms included one ectoproct bryozoan
colony (Plumatella sp.), several species of caddis fly larvae (Limnephilus
Neophylax) that were common, several bettle larvae (Hydropsyche ?),
and a variety of midge, or chironomid, larvae that were common.
Films of sessile and other diatoms coated many of the larger protruding
pebbles. Scrapings revealed both filamentous and nonfilamentous green
algaej in two spots there was appreciable blue-green algal growth
(Oscillatoria) strongly suggesting local enrichment that dissipated
downstream quickly enough to not allow further growth.
In September 1971, in two low-velocity pools, chironomid midge larvae
(unidentified green variety) were common on stout submerged logs. In
the substrate were rare nematodes and aquatic oligochaetes.
A soft yellow, apparently bacterial, slime streamed out from twigs
and pebbles in tufts. Diatoms on exposed surfaces were rare, but
among the bacterial filaments small phytoflagellates were common.
An occasional larger euglenoid appeared as well. There were a few
small ciliates, a few large ciliates (Loxodes), and hypotrichs ranged
from few to common. This association, found over much of the stream,
80
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was strongly indicative of a polluted condition and was borne out by the
presence of scavenging gastrotrichs, scavenging midge larvae, and
diatoms that appeared to be Nitzschia.
By May 1972, nearly all of the above organisms were absent from the
Upper Stream as well as the Lower Stream. The broad-shouldered
water striders were still present in reduced numbers, since they
theoretically are agile enough to avoid dangerous situations and capa-
ble of seeking minor shelter. Of the truly aquatic animals, only a few
caddis fly larvae were found surviving in their heavily-constructed
cases. All of the soft-bodied forms had disappeared, as had the algae.
In most cases, protruding stones, if they could be found, were scoured
clean even of diatoms.
Marginal vegetation along the banks was also severely affected. Much
of this had been apparent during the second survey when it was noticed
that the floodplain now reached beyond zones that would normally
support golden club, skunk cabbage, and cinnamon fern (remnants of
all were seen) into sassafras, greenbrier, beech, and oak regions.
What degrees of survival or transition might have occurred cannot
now be determined, since much of the region has been altered by
construction. The larger trees have been left, but whether their root
systems will tolerate repeated high water levels is conjectural.
While it is difficult to generalize about the entire stream, in November
1972 it possessed all of the following characteristics in the reaches of
the Lower Stream: heavy sedimentation of large abrasive particles
that lacked any degree of sphericity, banks that were deeply cut below
previous levels, often severely undercut with large chunks washing into
meanders; meander deposits consisting both of natural gravel and
crushed rock from construction; much debris consisting of brush,
leaves, plastic sheeting, etc. ; some evidence of iron bacteria in
lateral rivulets; no signs of established aquatic vegetation; slight
opalescence and some foam in pools. The only animal organisms
collected were two aquatic oligochaetes.
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In short, the stream at present is very nearly abiotic, at least of
macrobiota and large microbiota (bacterial cultures were not attempted).
Nevertheless, with proper effort and sufficient time, a stream of this
size, with no major pollutant contributions, should recover. It would
appear that the greatest problem facing the reestablishment of life in
the stream bed is the control of excessive runoff and sedimentation.
Pond. While the pond receives excessive quantities of sediment from
stream and bank drainage, is often totally opaque due to suspended or
colloidal particles, and is blanketed with thick bottom deposits, at no
time during this survey has it failed to support life, often of an unex-
pected variety and abundance. To date, most of the biota is composed
of small, easily-overlooked organisms. They are, nevertheless, of
considerable biological significance. Major trauma, such as hydraulic
dredging and lowering of water level, flood rise and major sediment
transport, probable enrichment from surrounding lawns and planting,
have, at most, only temporarily delayed the expected stages of aquatic
succession.
It is far from a balanced pond community. For example, the benthic
community, normally so important to the exchange of nutrients and
nitrification, is almost completely absent due to the suffocating effects
of clay-sized particles that carpet the bottom more than 1 m. thick.
Such pioneer rooted emergents as have been seen around the pond
margins on one survey, often are found destroyed on the subsequent
trip. The opacity of the water prevents primary production by algae
or spermatophytes more than a few centimeters deep. Clearing is
remarkably slow due to the minute size of suspended particles.
Nevertheless, the littoral zone is biologically very active, and the
plankton populations have not only shown continued growth, but a truly
remarkable increase in variety, which must be construed as a tentative
approach to health. When sediment levels fall and the water clears,
when organic detritus builds upon the substrate of clay, the nucleus of
biota already present will allow growth and production toward a mature
pond.
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Early in the sampling (June 1971), many of the plankters still dominating
were already present, although plankton diversity was not so great as
today. Phytoflagellates were uncommon, blue-green algae (Oscillatoria)
rare, and one diatom (Pinnularia) was common to abundant. One ciliate
(Dileptus) was rare, but the rotifers were abundant in toto, although at
the species level, only one (Asplanchna) was common. Others (Keratella.
Polyarthra, Noteus, and Cephalodella) occurred more sporadically.
The predaceous midge larva (Corethra) was a surprising find, since
it usually occurs in lakes, not ponds. Of planktonic crustaceans, only
Diaptomus and its nauplius larvae appeared; both were common.
In September 1971, after a long summer growing season, the pond
harbored a wide variety of aquatic and migrant organisms. The water,
while still tan with clay particles, had a greenish cast that was not
entirely borne out by its plankton populations, described shortly. Black
ducks were seen feeding along the shoreline; tadpoles (Rana clamitans ?)
were common in the shallows, as were small diving beetles (Haliplus).
A few rooted emergent seed plants (Scirpus, one Typha) had appeared
along the shoreline, and a single frond of crisp-leaf pondweed
(Potamogeton natans) was collected with a dip net. A few small
patches of filamentous green algae floated at the surface at the lower
end of the pond, but there was no obvious bloom.
Plankton tows yielded a wide variety and huge populations at this
period. Algal indicators of water quality were somewhat contradictory,
with filamentous blue-greens (Oscillatoria) very abundant, euglenoids
(Euglena) common, both being indicative of organic enrichment or
pollution, but Ankistrodesmus falcatus var. acicularis, a green unicell
characteristic of clean water, abundant as well. The filamentous
green alga, Spirogyra, was common, and the desmid Closterium, rare.
There were several species of small phytomonads, possible indicators
of pollution, and on-the-spot microscopy revealed a high count of
active bacilli. Diatoms were represented mostly by Pinnularia,
generally recognized as a clean water form; it was common. Fragillaria
83
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was present, but uncommon; Diatoma was common, although only
toward the lower end of the pond.
Among the zooplankton, filter-fee ding protozoans and rotifers dominated.
Vorticella monilata occurred commonly on surfaces along the shoreline,
while another ciliate protozoan (Dileptus) was common in plankton hauls.
Rotifers in toto were abundant, indvidual species ranging from common
to abundant (Keratella, Euchlanis, Die ranophorus, Polyarthra, Sync ha eta
--not in order of relative abundance). A few other ciliates (Urocentrum
turbo) and rotifers (Monommata) were seen, but only rarely.
Copepod crustacean nauplius larvae were abundant, as were adults of
one species (Diaptomus), while another adult (Canthocamptus) was
uncommon. A predaceous midge larva (Corethra) was present in the
plankton, but curiously one of its staple types of food, the entire group
of cladoceran Crustacea, appeared to be totally absent (see text for
November 1972).
By mid-May 1972, after a period of winter quiescence, a wide plankton
diversity continued unabated. Most notable was the presence of enormous
numbers of algal primary producers, notably a slender green desmid
(Ankistrodesmus falcatus var. acicularis) which is recognized as an
indicator of clean water. An indicator to the contrary, Euglena. was
seen but rarely. Diatoms in toto and separately were abundant, all
of which species seen are associated with biologically clean water.
While most of the diatoms were planktonic, some were associated
with three species'of filamentous green algae that flourished in shallow
water along the western shoreline. The dominant green filament was
of a Ulothrix-type, but an unfamiliar variety. Attached to this were
such diatoms as Gomphonema and Navicula, while planktonic diatoms
included Diatoma, Fragillaria, Meridion. Tabellaria, Surirella, and
Navicula. Fragillaria was abundant, Navicula and Gomphonema common.
The only desmid other than Ankistrodesmus (the most abundant organism
present) was a rare Cosmarium.
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Other than several unidentified ostracods and a few very small Kurzia-
type cladocerans, the zooplankton was almost absent. On the other
hand, bottom samples and culling through the algal masses yielded
nematodes, chironomid midge larvae, dragonfly nymphs (the large
Anax), Hydra oligactis, unidentified damselfly nymphs, gastropod
molluscs (Physa), aquatic oligochaetes, a larval salamander (Plethodon
sp.), and several fishfly larvae (Chauliodes).
The final pond survey was conducted in mid-November 1972. The
water was totally opaque due to an extraordinarily heavy load of clay-
sized and colloidal particles. The substrate was slippery, dense, and
almost completely impenetrable by infaunal animals or root systems.
The west bank was cut over but not eroded, while the east bank had
been graded, seeded, but left with bare earth along the shoreline.
There was no evidence of rooted aquatic emergent plants on either
shore, although the island appeared well vegetated and possessed
some emergents, a possible stock source for natural dispersal.
Dissolved oxygen levels were somewhat lower than usual at the surface
(9. 75 ppm); nevertheless the plankton community was flourishing.
From fragments along the shore, it appeared that blue flag and water
hemlock had grown recently somewhere along the pond margin. In
the water, several extensive masses of filamentous green alga
(Spirogyra) supported an extensive community of life-forms. Earlier
filamentous greens noted on previous surveys seemed to have been
succeeded by Spirogyra. Its filaments were not heavily fouled, as
had been the case with Ulothrix earlier, although there was some
evidence of clusters of one type of diatom (Navicula) attaching.
Ciliate protozoans (Vorticella sp. ) were attached, but little else.
Interspersed in the algal masses were a few smaller primary producers,
notably desmids and some free-living diatoms (Gyrosigma).
One rotifer (Notommata copeus) was common, as were ovigerous
copepod crustaceans (Cyclops). Among the larger animal life-forms,
two or three species of myfly nymph (one was Bactis), one gastropod
85
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mollusc (Physa), one damselfly nymph, a black chironomid midge
larva, and a water-boatman (Corixa), all approached being common.
Semiaquatic oligochaete worms were present in the saturated littoral,
but not in the substrate which seemed abiotic.
The plankton community on this date was characterized by an explosion
of cladoceran crustaceans which in previous surveys had been nearly
absent. All cladocerans were common, some abundant, especially a
small, two-eyed species that remains unidentified. Others included
Bosmina sp., Bosmina longirostris, Daphnia, Ophryoxus. Alonella
nana, Chydorus, and Macrothrix; an unusually wide variety for one
order of Crustacea. Among the copepod crustaceans, Diaptomus was
still abundant, and another unidentified form was present, but uncommon.
Hydra oligactis was collected with the plankton, but either came from
the surface film or from the algal masses close to shore. This
coelenterate was almost common. In every case it was found to have
eaten several cladocerans, but no copepods.
The only other crustaceans present were two species of ostracods,
both unidentified, one large form being common. Nauplius larvae of
the copepods were, of course, common.
Rotifer populations were sparse, with only Keratella showing up
repeatedly, therefore abundant. Ciliate protozoans were uncommon,
with only the motile form of Vorticella appearing more than a few
times; it was still uncommon, however. Single sightings were made
of a large unidentified ciliate and a small nonphotosynthetic flagellate.
Several rhabdocoel flatworms were collected, but not identifed. The
euglenoid Phacus was the only suggestion of unclean water, but it was
rare and therefore not indicative.
The Spillway Stream is a stream seriously affected by many of the
same conditions present in the upper watershed area, but unlike that
region has shown somewhat greater stability with small populations
of fluviatile plants and lotic fauna.
86
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SUMMARY STATEMENT
As noted earlier, the lotic environment of the stream is all but destroyed.
Its present condition is due almost entirely to a lack of stability, with
accompanying heavy sedimentation and abrasive particle transport.
Originally it supported a fairly normal coastal plain association of
organisms, including aquatic and marsh plants, and animals charac-
teristic of both saturated soil and open flowing waters, riffle and pool.
While some of the more mobile fauna (salamanders, oligochaete worms)
are still present along the stream banks or within the coarse substrate,
little remains of the once-flourishing aquatic insect population, liver-
worts, mosses, fluviatile algae, and rooted aquatic plants.
Should the banks of the stream be stabilized in the future by new vege-
tation, the runoff of organic compounds discouraged, and storm water
management measures taken to reduce the volume of periodic surges,
the stream could recover a measure of its former condition. It is
unlikely, however, that stream bank, pool, and riffle diversity will
ever be as great again, primarily because of efforts needed to manage
a simplifed and controlled watershed.
The lentic environment of the pond, while affected, at times severely
so and still reduced in environmental opportunities, nevertheless gives
the impression of an ecosystem showing rapid trends toward a natural
succession of life-forms. This succession is delayed, however, by
sediment that continues to escape the forebay, descending to carpet
the substrate or creating an opacity that denies light penetration,
thereby limiting the photic zone close to the shoreline and to a depth of
only a few centimeters. So long as this occurs, primary production
is impossible in all but the shallowest littoral regions. The substrate
itself, a thick blanket built from precipitating clay-sized particles,
denies entrance or penetration by burrowing infaunal forms which,
through their activities, create turnover and prevent consolidation of
sediment, inhibits root development, and is unattractive to the highly
selective epifaunal forms that normally would browse across such a
87
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wide expanse. In short, the benthic community Still is not established,
and at no time have cores or bottom-grabs yielded anything other than
an occasional epifaunal life-form, usually an immature aquatic insect.
The pond's main problem of excessive sedimentation is accompanied by
a slight degree of eutrophication. This was not serious on the sampling
dates, although at times it may have been, or may be in the future.
What is especially striking in the biological samples obtained during
the various Surveys over an extended period of time is the gradual
establishment of a healthy, diversified plankton population which is
sensitive to, and reflects, physico-chemical parameters as well as
biological interactions. This augers well for the eventual successful
development of a diversified biotic community including tracheophyte
plants and vertebrate animals, but only if the particle load can be
reduced.
Without control measures, it is difficult to project what the eventual
outcome will be, especially if the stream and forebay continue to
contribute massive quantities of sediment into the pond with every rain.
Certainly the role of benthos in turnover, in decomposition, in the
production of nutrients, is an important One to the continued succession
of a pond community. Presumably the nutrient requirements of
phytoplankton are currently being met by the occasional flushing from
seeded areas of applied fertilizers, but as the bordering plots and
lawns are still new and only recently under cultivation, the results
have not been marked among the photosynthetic algae.
When construction is complete and the area has become stabilized, the
pond should be cleaned once more. When cleaning is complete, shrubs
and trees should be established around the pond. Rooted aquatic littoral
plants can then take hold, their deciduous leaf-fall soon resulting in a
loose carpet of organic detritus, encouraging invasion by organisms to
greater depths and more extensive areas than now occurs along the
substrate.
88
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The banks of the pond on the east side were raw at the time of the last
survey with no natural vegetation between what appears to be a flood
level and new lawns. It is essential to encourage the planting of moist
soil shrubs (button-bush, etc.) and trees (willows, etc.) as well as the
natural growth of rooted emergent and floating-leaf aquatic plants (arrow-
head, loosestrife, spatterdock, etc. . A zone of such emergents and
floating-leaf plants should be allowed along both shorelines to provide
shelter, feeding stations, and breeding opportunities to a wide variety
of aquatic organisms. A desirable result would be at least one focal
point in a food web: pond fishes of the sunfish and bass type. Some
fishes have entered the pond on their own accord (eels) and others have
been released there (blue gills, pumpkin-seed, white crappies, large
mouth bass) but this survey failed to find evidence of them. The pond
as yet does not appear suitable for maintaining a sustained population.
Once littoral zones of vegetation are established, the fauna, from
protozoan to vertebrate, will follow; nearly every pond animal also
has its preferred zone of activity determined by plant community.
With an increase in rooted vegetation near the head of the pond, close
to the forebay (if it can survive there), its screening action presumably
could cause an increase in the precipitation of inorganic particulate
matter, to a certain degree clearing the water. Generally, heavily
vegetated ponds are clearer than those without rooted aquatic vegetation.
The west bank of the pond still has not been laid bare, but seems to
have been mowed repeatedly and also is destitute of natural shoreline
vegetation with the exception of a few pioneering aquatic grasses (rush,
sedge). The island, on the other hand, appears largely unaltered from
earlier visits and could provide a nucleus of shelter for such fishes,
reptiles, amphibians, and aquatic invertebrates as now exist in the
pond, as well as a source of residual breeding populations, the
production of eggs, seeds, and spores. While plans are underway
to open the island by means of a bridge, it is hoped that its natural
vegetation will only be slightly altered, and that subsequent development
and planting of the island be conducive to maintaining it as a miniature
89
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natural preserve. A few hardy trees and shrubs would greatly add to both
its permanence and its function in the pond ecosystem.
Given time, care, and the proper continuing ecological attention,
Hittman Pond could become an extraordinarily attractive and productive
resource to the community.
Methods used in the course of these ecological studies included:
1. Field observations made in situ.
2. Collections: studied fresh when possible; otherwise
preserved for analysis in the laboratory.
3. Hydrology:
- Temperature
- pH
- Dissolved oxygen
- Forel-Ule color scale
- Transparency (Secchi disk; colorimeter)
4. Biology:
- Ekman dredge
- Peterson dredge
- ,25m plankton net + centrifugation
- Dip net
- Minnow net
c 2 ,
- .5m sampler
- Coring device
- Sediment sampler
- Stream sampler
- Fouling plates
- Foerst bottle
- Herbarium press
-------
5. Laboratory:
M ic r oc ent r if uge
Near-ultra centrifuge for nannoplankton
Leitz Labolux phase contrast microscope
B&L Greenough stereo for scanning
Counting chambers (S-R)
Culture chambers, controlled environment
chamber, incubator
Herbarium
Leitz-Nikon photomicroscope
6. References:
- Library of 60+ standard limnological texts
- Reprint collection in limnology
91
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SECTION VII
SEDIMENT AND WATER QUALITY STUDIES
The success of a sediment pollution control program depends not only
on trapping waterborne sediment in suitable devices, but also on the
ultimate disposal of the material in such a way that it will not cause
subsequent pollution by reentry into streams. The major portion of this
section of the demonstration program was devoted to evaluating, testing,
and demonstrating alternative techniques and practices for sediment
removal, handling, drying, conditioning, and disposal.
ENTRAPMENT
The primary facility for entrapping sediment from storm water runoff in
the project watershed was the storm water retention pond discussed in
Section V. In order to reduce the quantity of sediment being transported
into the pond and to help facilitate sediment removal, an engineered
forebay was designed and constructed. The criteria and rational used
to design the forebay are presented in Appendix C. In essence, an
engineered forebay is a settling basin located at the junction of a stream
with a pond and separated from the pond proper by a submersed weir or
dam. A forebay serves as an entrapment device for both bed load and
suspended sediments.
The final forebay design that was incorporated with the storm water
retention pond is shown in Figure 18. The forebay surface area is
2
approximately 9000 ft and is arranged in a trapezoidal shape with the
wide end adjacent to the pond. The pond and forebay are separated by
a submerged dam whose elevation is about one foot below the normal
pond elevation. The length of the submersed dam (maximum forebay
width) is approximately 100 feet. The depth of the forebay adjacent to
the dam is about five feet. The forebay length is about 175 feet and the
side walls have a nominal 4 to 1 slope.
92
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CD
CO
'"I«M FLOOD EL. S11.00'
WATE-H LEVEL 315 00 NOBMAL I
Figure 18. Forebay Design
-------
Attempts were made to compile simultaneous water quality data from
Station 3 and water quality and flow data from Station 4 in order to
develop information on the trap efficiency of the combined forebay and
pond as a function of overflow rate. The water quality data from Sta-
tion 4 which could be directly related to the other data were extremely
limited and no overall correlation could be derived. From limited
observations at selected storm overflow conditions, the actual trap
efficiencies (82 to 86 percent removal of suspended solids) were gener-
ally higher than one would predict on a theoretical basis (70 to 75 percent)
for the same flow conditions. It is estimated that the overall trap
efficiency of the forebay and pond over the demonstration period was in
excess of 95 percent, including bedload.
REMOVAL
Several techniques for removing sediment from the storm water reten-
tion pond and forebay were evaluated. Primary consideration was given
to evaluating which method of combination of methods would accomplish
efficient and economical sediment removal, while minimizing sur-
rounding site disturbance. The alternative approaches selected for
detailed evaluation were:
1. Conventional dragline
2. Underwater scoop with a long reach
3. Conventional hydraulic dredge with a pipeline to the disposal area
4. Conventional hydraulic dredge to forebay
5. Submerged roads
6. Special on-site dewatering facilities
7. Combined scoop/dredge
A summary evaluation of these alternatives is presented in Appendix D.
The techniques finally selected for demonstrating sediment removal were
conventional dragline, underwater scoop with a long reach, and utilization
of the forebay as a sediment holding and dewatering area prior to hauling
away by conventional dump truck. The principal of the underwater scoop
is shown in Appendix D.
94
-------
By including the forebay dam, it was possible to isolate the forebay
area by lowering the pond level and diverting the base stream flow.
Once isolated, the forebay contents could be partially dewatered in
place by batchwise decanting without disrupting the pond shoreline. The
employment of an underwater scoop to bring pond sediments into the
forebay necessitated special requirements in the forebay dam design
and construction such that it could withstand the impact forces of the
scoop bucket.
Sediment removal operations were begun on May 1, 1972 and were
completed on the 19th of May. Five days were required to clean the
forebay, seven days were spent removing pond sediments, and the
remaining six days were idle due to rain or weakends. A total of
o
approximately 700 yd of sediment were removed from the forebay
Q
and 1300 yd from the pond.
The first operation was the construction of a stream diversion channel
around the forebay to the pond. The stream flow was thus routed
directly to the pond which enabled the forebay to be separated from
the stream to pond system. Water was then decanted from the
forebay leaving relatively dry sediment materials.
Sediment was removed from the forebay by conventional dragline and
loaded directly onto conventional dump trucks. Figure 19 illustrates
the conventional drag line-dump truck operation. The drag line oper-
ation proved to be time-consuming and inefficient because the bucket
frequently spilled sediment material before it could be loaded.
After sediments from the forebay had been removed, the drag line
bucket was replaced with the long reach sediment scoop arrangement
shown in Figure 20. Sediment from the pond was then scooped into the
forebay and then loaded by backhoe onto dump trucks. The arrangement
of scooping sediment into the forebay and simultaneous removal from
the forebay and loading by backhoe resulted in the most efficient
sediment removal technique that was demonstrated.
95
-------
Figure 19. Conventional Dragline - Dump Truck Operation
Figure 20. Long Reach Scoop Arrangement
96
-------
It is worthy of notation in this document that a new machine, designed
specifically to remove sediment from small lakes and ponds, has
become commercially available since final arrangements for sediment
removal were made for this demonstration. The device, called the
MUDCAT, is currently (June 1973) being evaluated on another EPA
sponsored project.
Sediment Removal Costs
The equipment operation costs associated with removing and trans-
porting sediment one and a half miles by dump truck to the disposal
site are presented in Table 7. The D-8 caterpiller was used solely
as a deadman during the cable supported underwater scoop operations.
If a less expensive deadman arrangement had been employed, the
cost per yard would be reduced from $3. 80 to about $3. 00.
TABLE 7. POND AND FOREBAY SEDIMENT REMOVAL COSTS
Equipment Items Dollar Cost/hr Hours of Operation Total Cost
1.
2.
3.
4.
5.
Front end loader
and operator
One yard bucket
backhold
Crane and one
yard bucket
D-8 caterpillar
Five- 10 yard
dump trucks
24.00
40.00
35. 00
35.00
16.50
21
28
84
49
84
$ 504
1, 120
2,940
1,715
1, 386
$ 7,665
DRYING
Several methods were considered for effective drying of sediment.
These included the use of both chemical and physical methods to en-
hance the rate of drainage and drying.
A wide variety of chemical conditioners, including Dow A21, Hercufloc
6217, Hercufloc 6175, and Dow N17, were tested under laboratory
97
-------
conditions for their effect on sediment drainability. The test results
indicated that, in general, chemical conditioners would be impractical
under field conditions. A description of the laboratory sediment
studies is presented in Appendix E.
Physical methods of sediment dewatering proved to be reasonably
effective and practical. The physical techniques investigated included
the use of the forebay as a partial draining device during pond clean-
ing, sand drying beds, grass filter strips, and surface scarification
of disposed sediment to enhance drying.
Sand drying beds were effective in aiding both coarse and fine textured
sediment dewatering by downward drainage. Increased dewatering
rates were most notable with the coarse grained materials. In general,
the finer the sediment material, the less marked was the increased
dewatering rate. These results were to be expected.
The establishment of a grass filter strip around the sediment disposal
area provided an effective means of capturing solids that would normally
have been carried away with the sediment drain water. The filter strip
also helped to retard erosion around the disposal site.
Sediment surface scarification was effective in aiding the immediate
drying to a depth of approximately one foot. This effect was most
evident with the fine grained materials.
Utilization of the forebay as a partial draining device during pond
cleaning was difficult to evaluate under field conditions because a
number of springs fed directly into the forebay. The absence of
sediment leakage from the dump trucks during transport to the dis-
posal site indicated that prolonged forebay dewatering was unnecessary.
CONDITIONING AND DISPOSAL
Field studies were conducted to determine the feasibility of manipula-
ting sediment in order to acquire a material with improved character-
istics. The details of these studies are presented in Appendix F.
98
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Several low cost and usually available materials were tested for their
effectiveness as sediment conditioners. These included digested sewage
sludge, fly ash, woodchips, high magnesium lime, and 10-10-10
fertilizer.
These following materials were applied to four demonstration drying
beds in the following amounts:
Digested sludge (40% solids) 5 Ibs/sq ft
Woodchips 4 Ibs/sq ft
Fly ash 5 Ibs/sq ft
Lime 0.4 Ibs/sq ft
Fertilizer 0.4 Ibs/sq ft
Each drying bed was divided into four plots. Each plot measured
7 feet by 13 feet. Conditioning materials were mixed in with the top
six inches of sediment. Kentucky 31 Tall Fescue grass seed was then
sown and the following response parameters were observed:
1. Germination period
2. Density and coverage
3. Quality of plants
The following general observations were noted:
1. Grass seed germination occured first on plots containing
digested sewage treatment plant sludge.
2. Plots containing fly ash germinated two weeks later than
control plots.
3. Areas containing woodchips had stunted and sparse grass
growth.
4. Grass coverage and density was greatest on the fertilizer
and sewage sludge plots.
5. Plant response on plots treated with lime was similar to
the control plots.
99
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6. Plots treated with lime experienced dense rapid grass
growth during the first few weeks. Signs of nutrient
deficiency became apparent during the second month of growth.
WATER QUALITY
A base flow sampling and analysis program was conducted during the
demonstration period to determine the background water quality prior
to watershed development and what changes, if any, occurred during
development. Base flow water samples were periodically taken up-
stream of the forebay, at the forebay, and downstream of the pond
by automatic and hand sampling techniques. Water samples used for
base flow analyses were always collected after several days without
rain.
The parameters used to describe water quality were turbidity, sus-
pended solids, pH, total alkalinity, total hardness, chloride content,
nitrite and nitrate content, total phosphate content, and chemical
oxygen demand (COD). Over the term of the demonstration period,
the following base flow water quality observations were made:
1. Little difference in quality was noted between pond influent
and effluent samples.
2. Turbidity and suspended solids measurements increased.
3. Alkalinity, hardness, and chloride measurements remained
about the same.
4. Nitrite, nitrate, and total phosphate measurements increased
significantly.
Table 8 presents average water quality values during the
beginning, middle, and end of the demonstration period.
100
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TABLE 8 . AVERAGE WATER QUALITY DURING BASE FLOW CONDITIONS
Water Quality Parameters
Period
Beginning of Project
Middle of Project
End of Project
Turbidit>
(JTU)
8
10
14
' S.S. A
(me/D pH
11 7.2
15
18
7.4
7.3
Total
.Ikalinity
(mg/je)
24
21
23
Total
Hardness
(mg/j&)
18
14
16
Cl
(me/D
8
8
7
NO2 & NO3 PO4 COD
(me ID (me ID (me ID
0.2
0. 8
1.2
<0. 1
0.2
0.3
24
25
26
-------
SECTION VIII
REFERENCES
1. Guidelines for Erosion and Sediment Control Planning and
Implementation, Water Resources Administration, State of
Maryland and Hittman Associates, Inc., for EPA, EPA Report
No. EPA-R2-72-015, August 1972.
2. Young, Robert L., "Above Lake Needwood, " presented at Winter
Meeting, Interstate Commission on the Potomac River Basin,
Fredericksburg, Virginia, February 29, 1968.
3. Storm Water Management .Model, Metcalf & Eddy, Inc., University
of Florida, and Water Resources Engineers, Inc., for EPA,
4 Volumes, EPA Report Nos., 11024DOC07/71, 11024DOC08/71,
11024DOC09/71, and 11024DOC10/71.
102
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SECTION IX
APPENDICES
Section Page
A. Storm Water Management Pond Hydrologic Data 104
B. Selected Stream Channel Sections 108
C. Engineered Forebay Design Criteria and Sediment
Accumulation 132
D. Feasibility Study of Pond Sediment Removal Techniques . 136
E. Laboratory Sediment Studies 157
F. Field Studies for Evaluation of Sediment Drying,
Conditioning, and Disposal 161
103
-------
APPENDIX A
STORMWATER MANAGEMENT POND HYDROLOGIC DATA
Included herein are the basic hydrologic and meteorologic data used for
the stormwater retention pond analyses.
104
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TABLE A-l. POND PEAK FLOW PERFORMANCE:
INITIAL LEVEL AT NORMAL RISER ELEVATION
o
01
Date Total
of Rainfall
Storm (in. )
5/12-5/13/71
5/15-5/16/71
5/30/71
5/30-5/31/71
7/1/71
7/1/71
8/3-8/4/71
8/4-8/5/71
9/11/71
9/12/71
9/12-9/13/71
10/9-10/10/71
11/24-11/25/71
11/29/71
12/6-12/7/71
1/2/72
1/4-1/5/72
1/9/72
2/12-2/13/72
4/16/72
4/17/72
1.92
1.21
0.95
1.05
0.43
0.50
0.62
0. 68
0.63
0.28
0.93
1.93
2.80
0,75
0. 98
0.65
0.55
0.53
1.38
0.78
0.08
Approximate
Duration Return Interval Peak
of of Inflow
Storm Storm (CFS)
(min.) (yr.) (Station #3)
630 <1
840- <1
555 <1
345 <1
105 <1
135 <1
345 <1
540 <1
105 <1
120 <1
195 <1
1080 <1
870 <1
360 <1
1005 <1
750 <1
1080 <1
- 600 <1
675 <1
185 <1
55 <1
42.2
11.6
4.9
10. 8
7.7
19.0
5.0
13.8
54.0
22.0
49.3
27.5
37.5
9.2
8.7
2.9
3.2
4.2
14.0
31.0
4.3
Peak
Outflow
(CFS)
(Station #4)
120
12.6
4.4
18.0
3.1
10.0
2.2
3.8
13.6
2.7
21.2
90.0
142
9.2
4.5
2.2
3.0
3.0
16.3
9.2
3.5
Time
Between
Peak Inflow
& Outflow
(min. ) Remarks
40
10
90
180
65
70
190
25
90
75
100
30
25 Emergency Spillway
Flowed
90
*
60
135
150
110
105
180
'Data not available
-------
TABLE A-2. FULL POND PERFORMANCE CHARACTERISTICS DATA BANK
Total
Rainfall
(in.)
O.C8
0.28
0.43
0.50
0.53
0.55
0.62
0.63
0 0.65
en
0.68
0.75
0.78
0.93
0.95
0.98
1.05
1.21
1.38
1.92
1.93
2.80
Duration
of Storm
(min. )
55
120
105
135
600
1080
345
105
750
540
360
185
195
555
1005
345
840
675
630
1080
870
Average
Intensity
(in/hr)
0.087
0. 140
0.246
0.222
0.053
0.031
0.108
0.360
0.052
0.076
0.125
0.252
0.286
0.096
0.058
0.183
0.086
0.123
0.183
0.107
0.193
Peak
Inflow
(CFS)
4.3'
22.0
3.1
19.0
4.2
3.2
5.0
54.0
2.9
13.8
9.2
31.0
49.3
4.9
8.7
10.8
11.6
14.0
42.2
27.5
37.5
Time Between
Peak Inflow
& Outflow
(min. )
180
75
65
70
150
135
190
90
60
25
90
105
100
90
*
180
10
110
4t)
30
25
% Difference
in Peak Outflow
vs. Inflow (%)
-19
-88
-60
-47
-29
-6
-56
-75
-24
-72
0
-70
-57
-10
-49
+67
+9
+ 16
+184
+227
+278
Peak
Throughflow
(%)
81
12
40
53
71
94
44
25
76
28
100
30
43
90
52
167
109
116
284
327
379
Data not available
-------
TABLE A-3. POND PEAK FLOW PERFORMANCE:
WATER LEVEL BELOW NORMAL RISER ELEVATION AT START OF STORM
Approximate
Duration Return Interval
Date
of
Storm
7/29-7/30/71
7/30/71
8/11/71
8/19/71
8/26-8/27/71
9/11/71
9/17/71
10/1/71
10/2/71
10/23-10/24/71
10/25-10/26/71
11/3/71
4/13/72
4/13/72
5/4/72
5/19-5/20/72
Total
Rainfall
(in.)
0.81
0.25
0.62
2.10
4.15
3.28
1.25
0.10
0.70
0.85
1.70
0.50
0.82
0.73
0.60
1.13
of
Storm
(min. )
480
135
180
180
1380
480
60
60
510
1005
1080
395
245
285
240
765
of Peak Inflow
Storm (CFS)
(yr.) (Station #3)
<1 3.4
<1 4.0
<1 7.9
2.4
1-2 150
34.0
2-5 134
1-2 235
1-2 127
<1 2.1
<1 25.1
<1 3.0
2.4
2.2
<1 10.0
33.5
<1 4.5
6.0
<1 14.8
<1 31.6
<1 54.5
<1 10.5
Peak Outflow
(CFS)
(Station #4)
3.2
*
0.21
0. 12
3.2
5.6
232
183
3.2
*
0.51
0.13
0.16
0.11
4.8
39.2
0.05
0.21
0.32
1.8
2.2
0.27
% Difference
in Peak Outflow
vs. Inflow (%)
-6
*
-97
-95
-98
-84
+73
-22
-98
*
-98
-96
-93
-95
-52
+ 17
-99
-96
-98
-94
-96
-97
Peak
Throughflow
(%)
94
*
3
5
2
16
173
78
3
*
2
4
7
5
48
117
1
4
2
6
4
3
Time Between
Peak Inflow
& Outflow
(min.)
25
*
15
10
75
115
145
175
15
*
60
60
75
70
80
35
15
45
-75**
85
5
85
Initial Pond
Level (Ft. Below
Normal Riser
Elevation)
1/4
1-3/4
3
1-3/4
1
2-1/4
2-1/4
2-1/2
2-1/2
1
1/2
2
2-1/4
3/4
2-1/2
4
Remarks
Drawdown valve open full
during storm
Same rainfall event-two
distinct flow peaks
Same rainfall event-two
distinct flow peaks
Emergency spillway flowed
Emergency spillway flowed
Same rainfall event -three
distinct flow peaks
Same rainfall event-two
distinct flow peaks
Same rainfall event-two
distinct flow peaks
Drawdown valve open 10%
during storm
No distinct peak recorded at station #4.
Station 14 peaked before station #3.
-------
APPENDIX B
SELECTED STREAM CHANNEL SECTIONS
Included herein are the surveyed stream channel cross sections F
through M used in reference to the stream channel morphology section
of this report*
108
-------
FEET
408
F-l
- I
EAST-
F-2
160
I
140
I
120
I
100
I
80
i
60
40
404—
o
CD
-i
w
396 —
Figure B-l. Section F (Stream)
10/22/70
-------
FEET
408 —
160
I
140
I
120
I
100
I
80
I
60
I
40
EAST
20
I
F-2
404 —
"F-1 not replaced because
of construction"
H
$
H
i-J
W
400 —
396 _
Figure B-2, Section F (Stream)
4/27/72
-------
G-l
20
I
FEET
40
I
EAST.
60
I
80
I
G-2
406 _
404 _
H
fa
w
-1
w
402 —
Figure B-3. Section G (Stream)
4/27/72
-------
G-l
FEET
EAST
20
»
40
60
80
l
G-2
406 _
404 —
H
fe
O
h—I
H
W
402 —
Figure B-4. Section G (Stream)
10/22/70
-------
EAST
415
413 —
411 _
409
I—I
H
407 _ >
J
W
405 —
403 —
80
I
H-2
I
Figure B-5. Section H (Stream)
10/22/70
-------
407_
405—
40
I
FEET
60
I
80
I
EAST
H-2 not reset because
of construction
403—
Figure B-6 Section H (Stream)
4/27/72
-------
FEET
CJl
418
417 _
416 ~
fc
^
O
KH
5
>
H
415 —
414 —
413 —
412
EAST-
1
Figure B-7. Section I (Stream)
10/22/70
-------
FEET
1-1
418
417 -
£ 416-
415 .
W
-I
W
414 ~
413 -
412 -
EAST.
Figure B-8. Section I (Stream)
4/27/72
-------
J-l
I
80
I
FEET
60
I
40
20
EAST
J-2
I
430_
428—
426—
H
fa
O
424— H
H
422—
Figure B-9 . Section J (Stream)
10/22/70
-------
FEET
80
I
60
I
40
I
EAST »»
20
I
J-2
I
CO
430 —
428 —
426 —
424 _
55
o
W
J
W
"j-1 not reset
because of construction"
422 —
Figure 10. Section J (Stream)
4/27/72
-------
FEET
K-l
1
20
I
40
i
60
I
EAST +•
-2
444 —
CD
O
H- 1
H
< 442
W
440 _
Figure B-ll. Section K (Stream)
10/22/70
-------
FEET
K-l
444 —
to
o
H
fa
H 442
,4
W
440
Figure B-12. Section K (Stream)
4/27/72
-------
FEET
EAST
£462
O
i — l
H
<
a
j
w
460
458
Figure B-13. Section L (Stream)
10/21/70
-------
FEET
462 —
to
CO
W
EAST-
80
I
L-2
I
460 —
458 —
Figure B- 14. Section L (Stream)
1/22/71
-------
FEET
60
to
00
EAST-
80
I
L-2
EH 462-
O
I 1
E-i
<
W
J
W
460—
458—
Figure B- 15. Section L (Stream)
4/28/71
-------
(Replaced)
FEET
to
S3
O
w
J
w
462 _
460 —
458
Figure 16. Section L (Stream)
7/26/71
-------
FEET
464
fa AR9. —
to
o
I—I
H
g
a
j
w
460 —
458 -
EAST-
80
I
L-2
I
Figure B- 17. Section L (Stream)
10/14/71
-------
FEEr
462 —
to
CT>
o
HH
H
EAST.
80
L-2
I
460 —
458 —
Figure B-18. Section L (Stream)
1/25/72
-------
FEET
40
60
464
CO
O
i—i
H
<
>
H
J
W
460 —
EAST
80
I
L-2
I
458 —
Figure B-19. Section L (Stream)
4/27/72
-------
M-l
I
FEET
472 —
CO
00
fa
2
H
>470
H
•J
468 —
Figure B-20. Section M (Stream)
1O/21/70
-------
CvS
CD
M-l
472 —
2
EH
<
w
J
w
470 —
FEET
-2
468 —
Figure B-21. Section M (Stream)
1/22/71
-------
CO
o
H
fa
O
I — |
H
<
>
W
470 —
468—
466 —
Figure B-22. Section M (Stream)
4/28/71
-------
M-l
Replaced
El=474.812
472 —
470 —
fe
£
O
i— i
H
Pd
468 _
EAST
M-2
El=478.90
466 —
Figure B-23. Section M (Stream)
1/25/71
-------
APPENDIX C
ENGINEERED FOREBAY DESIGN CRITERIA AND
SEDIMENT ACCUMULATION
An engineered forebay is an appropriately sized settling basin, located
at the confluence of a stream with a pond or lake. Its two principle
functions are to capture suspended and bed load sediments that would
normally be carried into the lake and to help facilitate sediment removal.
Figure-18 depicts the forebay design employed in the demonstration
project.
In discrete settling, the particle maintains its individuality and does
not change in shape, size, or density during the settling process, as
happens during flocculent settling. Naturally, settling suspended
sediments are characterized by discrete settling.
A discrete particle will settle when the impelling force of gravity
exceeds the inertial and viscous forces. The terminal settling velocity
of a particle is defined by the relationship:
4g(P - P,)D
V = s *
where:
P_ = specific gravity of the particle
s
P^ = specific gravity of the liquid
V = terminal settling velocity of the particle
D = diameter of the particle
C , = drag coefficient
2
g = gravitational constant (32 ft/sec )
The relationship used to describe the removal of discrete particles in
an ideal settling tank assumes the particles entering the tank are
132
-------
uniformly distributed over the influent cross section and that a particle
is considered removed when it hits the bottom of the tank. The settling
velocity of a particle which settles through a distance equal to the
effective depth of the tank during the theoretical detention period is
described by:
V = $
o A
where:
Q = rate of flow through the tank
A = tank surface area
All particles having settling velocities greater than V will be completely
removed, while particles with settling velocities less than V will be
removed in the ratio of V/V .
o
Figure C-l indicates a typical particle size profile for suspended
sediments in the demonstration watershed. Assuming a specific gravity
of 2.2 for the sediment and a 9000 sq ft forebay surface area, nominal
sediment removals were calculated. Figure C-2 indicates the range of
estimated sediment removals that would occur for varying flow rates
using a forebay with a surface area of 9000 sq ft. For example, during
a one year storm, the completed theoretical forebay entrapment
efficiency is approximately 18 percent by total sediment weight.
133
-------
100%-
80%-
q
Oj
.c
4_J
Si
0)
,—i
^H
OJ
a
CO
60%-
40%-
00
20%-
0%
I
100
T
10 100 1000
Effective Diameter (N)
I
10000
Figure C-l. Demonstration Pond Sediment Size Profile
-------
oo
100-
90-
+->
* 80-
.0
~ 70-
,—i
ri
o
S 60
cis 50
•«-H
S
O
2 40
30-
20
0.1
1
1.0
I
10.0
Inflow (CFS)
9000 sq ft Forebay
T
1
100. o' ' ! 1000.0
Figure C-2. Theoretical Forebay Sediment Removal Efficiencies
-------
APPENDIX D
FEASIBILITY STUDY OF
POND SEDIMENT REMOVAL TECHNIQUES
In order to ensure the success of the sediment and pollution control
program, it was imperative that the material trapped in the pond be
removed in a manner which will not allow significant amounts to return
to surface waters. This, of course, had to be done at a reasonable cost
and with minimum disruption to the surroundings, since the pond is in
a park-like setting. Most techniques used today fail to meet all of the
above requirements. Thus, new approaches had to be devised and/or
evaluated along with existing techniques. However, because this project
is not charged with developing new equipment, emphasis on the search
for improved techniques was limited to the use of equipment already
available. The following methods are discussed in this appendix:
1. Conventional dragline
2. Underwater scoops with a long reach
3. Hydraulic dredge with a pipeline to the disposal area
4. Hydraulic dredge to forebay
5. Submerged roads
6. Special on-site dewatering facilities
7. Combination scoop/dredge
Cost estimates have been based upon the maximum amount expected--
about 9000 cubic yards at 30 percent solids. Since the forebay is assumed
capable of removing one-third of the incoming material, pond cleaning
techniques have been evaluated on a basis of 6000 cubic yards at 30 per-
cent solids in place. Wherever possible, direct quotes from contactors
and equipment suppliers were obtained.
136
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DRAGLINE WITH CONVENTIONAL TRUCKS
The most commonly used method of cleaning ponds is the dragline.
This method involves the use of a crane with a special dragline bucket.
The crane is located on the bank of the pond. Through rapid rotation
of the boom, the bucket is thrown into the pond. The dragline bucket
is hauled in and the entrapped material is usually piled in windrows
along the bank of the pond.
The reach of the dragline is quite limited — usually no more than 60
feet from the crane. A longer reach can be achieved if a long boom
is used; however, this practice results in less efficient use of the
dragline bucket. In addition, the long boom can present difficulties
in transporting the dragline equipment to the pond site. Thus, the
cost per yard removed of a dragline operation with a conventional
boom is significantly lower than that with an extra long boom. Dragline
sediment removal, therefore, is generally limited to removing the
material near the shore line.
The usual method of dragline removal involves the piling of material
along the banks (in windrows) as it is collected. This provides an
opportunity for some dewatering. The solids are then transferred by
loader or crane to regular dump trucks for transport to a disposal site.
While piling in windrows aids in dewatering the sediment, the moisture
content of the solids is usually great enough to cause leakage from
regular truck bodies. It is estimated that air drying and dewatering in
windrows would raise the solids content of the sediment from 30, as
removed, to 40 percent after two days of dewatering.
3
The estimated cost of removing 6000 yd from the pond was estimated
to be approximately $12, 300. This does not include supervision, site
cleanup, or a. spotter at the dump location. Details of this estimate
are given in Table D-l.
This technique must be considered a minimal effort because of the
potential aesthetics problems that will result. Windrows of sediment
137
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TABLE D-l. ESTIMATED COST FOR DRAGLINE OPERATION
Basis: 6000 yd3 at 30% solids
A. Dragline
3 *
Approximate loading cycle for 1 yd bucket - 22 sec
Assume 50% efficiency in bucket
.'. 44 sec loading cycle
6000 yd3 x !- _ _ = 73.2hrs
J ,3 3600 sec
yd
Allowance for downtimes, equipment movement, etc. - 22. 8 hrs
.'. Estimated equipment operating time = 96 hrs
>|e3{«
Rental fee - $100 (Inst.) + $22/hr (Incl. operator)
= 100 + 22 x 96 = $2200
If banks are not firm enough to support crane without pads,
cost will be approximately doubled,
.'. Assume dragline cost = $4400
B. Front -End Loader
2
1-3/4 yd capacity - Assume same rate of operation as dragline
.'.12 days
%$:$:
Rental (Incl. operator) = $45 + 18/hr
.'. 45 + 18 x 96 = $1775
C. Conventional Dump Trucks
3
6 yd - traveling at 15 mph for 2 mile distance
Hauling cost estimated at $. 60/yd (Incl. operator)
6000 x $0.60 - $3600 x 1.25 (O.K. and profit) = $4500
##
6000/6 yd = 1000 trips at 15 mph = 300 hrs
. '.use 4 trucks
1.38
-------
TABLE D-l. ESTIMATED COST FOR DRAGLINE OPERATION
(Continued)
Using 10T trucks, rental**'' is $80/day (Incl. operator)
4 x 80 x 12 = $3840
.'. Assume $4500 as truck cost
D. Total Equipment Cost
Dragline $ 4, 400
Front-End Loader 1, 775
Trucking 4, 500
Subtotal $10, 675
Contingency (15%) 1, 600
Total $12, 275 or $2.05/yd3
E. Site Restoration Costs
Sod - 2 windrows 400 ft x 30 ft - 24, 000 sq ft @$0. 90/yd2
= $2,160
Labor - 5 man-day @$40 = 200
Total Site Costs $2, 360
F. Total Cost
Equipment $12,275
Site Restoration 2, 360
$14,635
#
"Dodge Estimating Guide for Public Works Construction, "
McGraw Hill, p. 136, 1970.
**
Cheasapeake Dredging Company, Baltimore, Maryland.
#*#
Joseph J. Hock, Inc., Baltimore, Maryland
**"Building Construction Cost Data, 1969, " Robert Snow Means
Company, Inc., p. 10, 1969.
139
-------
on the pond banks are sure to be a nuisance in the eyes of the nearby
residents. Once the sediment has been removed, the area where the
windrows were located will be unsightly so that a significant landscaping,
effort will be required to restore the area to an acceptable aesthetic
level. One method would be to lay sod in all disrupted areas. Assuming
windrows 400 feet long and 30 feet wide on each side of the pond, the
sodding costs alone would be $2, 160 ($. 90 per square yard installed).
In addition, about five days of labor at $40/day should be included for
other cleanup work. Thus, the total site restoration work is estimated
at $2, 360. Seeding the area would, of course, be less expensive but the
area would not regain its former aesthetic level or its ability to be used
as a park for a period of time that could be measured in months.
In addition, the use of conventional dump trucks would result in the loss
of significant amounts of sediment en route to the disposal area. This
material would not only create a nuisance but would find its way back
into nearby streams through storm water runoff.
In summary, dragline removal of sediment may be relatively inexpen-
sive; however, severe aesthetic problems result that can only be
remedied by expensive landscaping techniques. Total costs for removal
of 6000 tons of wet solids transport to the drying beds, plus site cleanup
are estimated at $14, 635.
It must also be noted that this estimate contains the inherent assumption
that all of the sediment can be removed by dragline. This, most likely,
will not be true since the dragline can only reach about 60 feet from the
shore. The pond is up to 250 feet wide. Thus, in the widest part of
the pond large areas would not be reached. In order for sediment in
these areas to be removed, it must slough or flow toward the shoreline
area. This is not likely to occur to a significant extent.
140
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CRANE OPERATED SCRAPERS
As mentioned in the previous section, one of the major drawbacks to
draglines is the limited reach of the dragline bucket which limits the
amount of material that can be removed. There are, however, variations
of the dragline approach which are capable of scraping the entire bottom
of the storm water retention pond. Several manufacturers produce special
scoops which are hauled in by conventional cranes or winches but are
returned by a cable attached to a "deadman" located some distance
away. This arrangement can increase the effective reach of a scoop
to over 1000 feet. The scoop operates in the same manner as a drag-
line bucket in that it scrapes the bottom and pulls the material in toward
the crane. The material is then piled along the shore in windrows. One
such approach involves the use of a conventional dragline crane and a
scoop and deadman manufactured by Sauerman Brothers, Inc. , of
Bellwood, Illinois. A typical arrangement is shown in Figure D-l.
Larger buckets and greater mobility can be achieved by using a boom
support for the crane and a bulldozer for the tail anchor (Figure D-2).
This evaluation is based upon the use of a 1-1/2 yard bucket with a
conventional dragline crane. Table D-2 presents the estimates developed
for two cases:
1. Case A scrape to a windrow along one bank, load conventional
dump truck with a front-end loader and transport to disposal
area.
2. Case B - scrape to forebay, allow to dewater, load conventional
dump trucks, and transport to disposal area.
Estimated costs including site cleanup are as follows:
1. Case A - $13, 150
2. Case B - $13, 150
The lower cost of a scraper over the use of a conventic ~al dragline is
mainly due to the longer reach of the scraper. Thus, only one windrow
is necessary using the scraper so that site restoration costs are
141
-------
CRESCENT SCRAPER
AND CARRIER
.TRACK CABLE
Figure D-l. Crane Operated Scraper, Typical Arrangement
BOOM SUPPORT
, GUIDE BLOCK
Figure D-2. Crane Operated Scraper, Alternate Arrangement
142
-------
TABLE D-2. ESTIMATED COST FOR SAUERMAN SCRAPER
Basis: 6000 yards at 30% solids; 1-1/2 cubic yards scraper bucket;
100.% of bucket volume utilized
Case A Scrap entire pond bottom to a windrow along one bank
(approximately 200 feet average width). Load onto dump
trucks from windrows.
(1) Equipment
(a) Crane and scraper complete
For 200 ft reach, loading cycle time =90 sec
.'. Dragline crane and bucket will be used
cr\r\r\ J 1.5 Hlin hr „,, .
6000 vd x -5—F—-T— x -XT? -— = 99 hr
1. 5 yd 60 mm
Add 36 hr for downtime, moving, etc.
.'. 135 hr total time - say 17 days
Rental fee for crane
$100 + 22 x 135 - $2600
Rental for scraper
$360/mo x 2 = $ 720
Total $3320
No allowance has been made for pads for the
crane since it can be moved back from the
pond edge.
(b) Front end loader
17 days x 8 x $18 + $45 = $2400
(c) Dump trucks
Same as for conventional
dragline = $4500
143
-------
TABLE D-2. ESTIMATED COST FOR SAUERMAN SCRAPER
(Continued)
(d) Total equipment costs
Crane and scraper $3, 320
Front end loader 2, 400
Dump trucks 4, 500
$10, 220
Contingency 15% 1, 530
$11, 750
(2) Site Restoration
(a) Sod - one windrow - 400 ft x30 ft
@$0. 90/yd2 (installed) $1,200
(b) Other - 5 man-days@$40/day 200
(c) Total site restoration 1, 400
(3) Total Case A Costs
Equipment $11, 750
Site Restoration 1, 400
$13, 150
Scrape to forebay (average distance - 300 ft) allow to
dewater and load onto dump trucks.
(1) Equipment
(a) Crane and scraper
For 300 ft. reach, complete loading
***=!<>!<
cycle time = 135 sec
cnnn 2. 25 min hr , cn ,
6000 x -—=—-, x ™ :— = 150 hr
1. 5 yd 60 mm
Assume 24 hr downtime, etc. (less
movement of deadman than in Case A)
.'. Total rental time = 174
144
-------
TABLE D-2. ESTIMATED COST FOR SAUERMAN SCRAPER
(Continued)
Crane rental
$100 + 22 x 174 = $ 3, 900
Scraper rental = 720
$ 4, 620
(b) Front end loader
22 days x 8 x 18 + $45 = 3, 200
(c) Dump trucks
Dewater in forebay. Assume 25 % reduction
in volume of sediment
.'. 3/4 x $4500 = 3, 380
(d) Total equipment cost
Crane and scraper = 4, 620
Front end loader = 3, 200
Dump trucks = 3, 380
$11, 200
Contingency 15% 700
$12,900
(2) Site Restoration
(a) Sod - 10 ft x 50 ft = 500 ft2 @$0. 90/yd2 = $ 45
(b) Other - 5 man-days at $40/day = 200
(c) Total site costs = 245
(3) Total Case B Costs
Equipment = $12,900
Site Restoration = 245
Total $13,145
*****Sauerman Brothers, Inc., Bellwood, Illinois, Technical Information
*See Table D-l.
145
-------
proportionally reduced. While total estimated costs for Cases A and B
are the same, there are some notable differences in the distribution of
costs within each estimate: (1) Case B has lower site restoration costs
since no windrows are formed; (2) trucking costs are lower in Case B
since the sediment will be partially dewatered in the forebay; and (3)
Case B required five more days to complete. Note that the cost of the
forebay has not been included in this evaluation.
Attempts were made to prepare estimates using the Terra-Marine Scoop,
a device similar to the Sauerman scraper except that the scoop is pulled
by a truck mounted winch. However, at the time this evaluation was
prepared, the manufacturer had not yet submitted the necessary cost
and engineering data. It is estimated, however, that the cost of this
3
scoop system will be about $l/yd , or $6000, for removal to the forebay.
This would be comparable in cost and effectiveness to the Sauerman
system.
HYDRAULIC DREDGE
Most large solids removal operations are accomplished by a hydraulic
dredge with mechanical cutter teeth. Sediment is loosened by the
mechanical teeth and swept up the intake pipe by hydraulic action. The
discharge from the dredge pump is directed to a spoils area for sub-
sequent dewatering. Because water is drawn into the intake pipe,
dredging usually is a clean operation in the immediate vicinity of the
intake pipe. On the other hand, proper disposal of the large quantities
of water required to move the sediment often is quite difficult to
accomplish.
Most floating dredges operate in a crab-like fashion. After the equip-
ment has been assembled and floating pipe laid to a fixed shore spoils
pipe system, the dredge drops a leg or spud to the bottom. The spud
acts as a pivot point for the dredge which slowly swings in an arc as it
removes sediment. Once the desired arc has been completed, a second
spud is dropped and the first retracted so that the dredge swings back
146
-------
along a similar arc that is transposed forward. Periodically, new
sections of floating pipe must be added as the dredge moves away from
its starting point.
In order to assess the cost and level of effort associated with hydraulic
dredging, the Mobile Dredging and Pumping Company of Exton,
Pennsylvania was requested to prepare estimates for three separate
cases given below. Pipeline transport to the disposal area was included
in two cases. The possible location of the pipeline is shown in Figure
D-3. At the time the estimate was requested, it was expected that
only 2000 yards of material would be removed. While the expected
volume has risen to 6000 yards, a new estimate was not prepared due
to the high cost previously given.
1. Case I
Install pipeline and pumping stations for solids transport
to sludge disposal area (distance - 10, 000 feet)
Clean pond once and remove pipe and pumping stations
Estimate sediment to be removed at 30% solids content
2000 yards3
Approximate length of pond 700 feet
Width - maximum 250 feet
minimum 10 feet
Water depth - maximum 9 feet
minimum 0 feet
Maximum length floating pipeline 600 feet
Minimum length floating pipeline 0 feet
Maximum length of shore pipeline to
disposal area 9400 feet
Approximate lift to disposal area 50 feet
Approximate sediment depth 0. 25 to 2 feet
147
-------
SEDIMENT DRYING & DISPOSAL AREA
Figure D-l. Possible Location of Sediment Transport Pipeline
148
-------
2- Case II
Install pipeline, etc., to sludge disposal area
Clean pond at the end of 1970, 1971, and 1972
Then, remove pipe and pumping stations
Estimated sediment to be removed (at 30% solids content)
1970 2, 000 yards3
1971 6,000
1972 2, 200
10,000
Pond dimensions and pipeline distances are the same
as in Case I
Approximate sediment depth
1970 0.25 to 2 feet
1971 0.75 to 4 feet
1972 0.25 to 2 feet
3. Case III
Pump dredged material to forebay area
Clean pond once
Estimated sediment to be removed at 30% solids content-
2000 yards3
Same pond dimensions, sediment depth, and floating
pipeline lengths as in Case I
No shore pipeline used
The Mobile Dredging and Pumping Company has supplied the following
estimates:
Case I $ 52, 280
Case II 136, 840
Case III 31, 100
149
-------
Since the only difference between Cases I and III is that in Case I the
sediment is pumped to the disposal area while in Case III it is pumped
to the forebay, one can conclude that the cost of pumping sediment to the
disposal area is about $20, 000 on a one-time basis. This includes setup
and removal of pipe and pumping stations, equipment rental, and operating
labor. The dredging company further estimated an equipment mobilization
cost for Case III of $3000. Thus, about $28, 000 is estimated for actual
dredging or about $14/yard.
This high unit cost is attributed by Mobile Dredging to the sensitivity
of dredging costs to area covered rather than depth of sediment. Evidently,
the major operating cost involves connecting new pipe as the dredge
"walks" along the pond bottom. According to Mobile Dredging, the total
cost would increase very little if the depth of sediment were greatly
increased to say 6 to 10 feet since the movement of the dredge would be
essentially the same as Case III, where the estimated sediment depth
ranges from 0. 25 to 2 feet for 2000 cubic yards at 30 percent solids.
Thus, if sediment was allowed to build up to 0. 75 to 6 feet (6000 cubic
yards), the unit cost would be about $3. 50-4 cubic yards. This is still
appreciably more expensive than the previous cases considered.
Mobile Dredging estimated that about two months would be required to
complete each dredging operation. The dredge is capable of covering
about 3500 square feet per day. Note that in Case III, the cost of solids
removal from the forebay and transportation to the disposal area is
not included.
Mobile Dredging estimated the cost of the three cases on the basis of
their smallest dredge which is a sizable piece of equipment. The dredge
is 8 ft x 12. 5 ft x 6 ft and has a 6 in. x 6 in. pump and is capable of
dredging to a depth of 21 feet. A smaller dredge could probably perform
as well for much lower cost; however, attempts to locate a small dredge
to purchase or rent in the Baltimore-Washington area have been
unsuccessful.
150
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UNDERWATER ROADS
All of the removal methods discussed thus far involve either some dis-
ruption of the pond banks or removing solids to the forebay. The forebay
will require fairly frequent cleaning so that the technique used should be
as rapid and efficient as possible. One technique which has been sug-
gested is the use of roads on the bottom of the forebay upon which front-
end loaders or draglines could operate when the forebay is drained, an
approach similar to the technique used at Lake Bancroft in Virginia.
This would represent an efficient and fairly clean operation since: (1)
the sediment would be subjected to minimal hauling; and (2) trucks would
be loaded in the forebay. This approach has also been considered for
cleaning the pond.
Consideration was given to the use of monolithic underwater concrete
roads on which to operate sediment removal equipment. These would
be formed and poured in place. However, this type of construction is
not recommended for several reasons. The limiting condition for the
design of an underwater road would have to assume that the underlying
soil could subside or be eroded from under the slab. This would result
in long unsupported lengths and would require that the road be designed
as a long beam. Relatively thick reinforced sections would be needed;
therefore, this is an expensive approach.
The road could also be designed as a series of relatively long slabs
(10 to 20 feet) to limit the possible length of unsupported slabs. For this
case, the maximum unsupported length would be determined by the area
of the slab less the area required to support the weight of the slab plus
equipment. This could still result in relatively long unsupported lengths
and relatively costly construction. There is also the possibility that
this type of construction could also become unusable; for example,
if the undermining occurred at the ends or sides of the slabs allowing
them to cant in relationship to each other.
.151
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For these reasons, the recommended construction for underwater roads
should take the form of relatively small blocks. Small blocks will settle
to conform to the bottom, have minimal unsupported lengths, and will
reduce the possibility of becoming canted to the point that they cannot be
used.
Small block underwater roads could be constructed using sectional
forms and in place pours or by the use of precast blocks. The precast
block concept is favored since the blocks will require reinforcement and
assembly line fabrication using standard components will undoubtly be
cheaper than field placement of reinforcing steel. Prestressing might
also be desirable to reduce the thickness of the block.
The optimum size for the blocks involves several considerations. The
area of each block must be adequate to support the weight of the most
heavily loaded wheel of the equipment that will be operated on the road.
Based on an allowable loading of two tons per square foot for the bottom
of the pond and a maximum load of 10, 000 pounds per wheel,the minimum
area should be 2. 5 square feet. Since the blocks will not be uniformly
loaded, the area will have to be larger. With small blocks,the weight
of the block will not be adequate to preclude tipping and some support
will be required from the underlying soil. Also, the vacuum created by
lifting the block will have to be relied upon to preclude tipping.
Unsuccessful attempts were made to obtain the design criteria for the
perforated concrete blocks which have been extensively used in Europe
for parking areas and roadways. In the absence of this information,
the following design has been assumed. The blocks would be about
3 feet square with 16-5 inch holes on 8-inch centers leaving a web of
3 inches between holes and 3-1/2 inches on the edges. This will provide
6. 8 square feet of bearing area. Based on a 10, 000 pound load in the
center and no ground support at the center, and using a simple reinforced
beam analysis, the required thickness is 5.3 inches, say 6 inches. The
weight of the block would be 500 pounds. With a prestressed block,the
thickness could probably be reduced to 4 inches.
152
-------
With a concentrated load on the edge of the block,the tipping moment
would be about 3000 to 4000 foot-pounds. Under this condition, the
righting moment of the block would be about 350 foot-pounds. However,
the lifting of the outer edge would create a partial vacuum. A partial
vacuum of about 4 to 5 psig would provide a sufficient force to resist
tipping. Since the holes in the slab will provide good assurance of
seating, only a severe undermining would cause the block to tip.
There is also a question as to whether the blocks should be used to form
a full width surface or whether two rows can be used to provide tracks
for the vehicles. This could reduce the number of blocks about a fourth,
with extra blocks used at intersections and turns.
In addition to attempts to obtain design information on the blocks from
European manufacturers, discussions were held with block fabricators
for local production. For blocks as described above, an initial estimate
of $2/square foot installed has been generated for preliminary purposes.
Blocks could be used in both the forebay and the pond. The basic forebay
design includes an underwater road adjacent and parallelto the forebay
dam which intersects with a road down the length of the forebay approxi-
mately following the longitudinal axis. Total road length is estimated at
250 feet. Assuming a 12-foot wide road, approximately 3000 square
feet of surface is involved. At $2/square foot, the approximate cost
for a road system in the forebay would be $6000. . This assumes that the
roads are laid with a minimum of clearance between adjacent blocks.
The cost of a road system in the pond using the above block design is
of significantly greater magnitude. If one assumes that the entire pond
will be cleaned by dragline operating from the roads, approximately
1750 feet of roadway are required to place all of the pond within a 50-
foot reach of the dragline. For a 12-foot wide roadway, approximately
21, 000 square feet of road surface must be provided. Thus, a complete
-------
underwater roadway for the pond would cost about $42, 000. This
could be lowered if:
(1) The blocks were laid in two tracks instead of a
"solid" roadway
(2) Roads were laid in the upper portion of the pond,
where most of the deposition is expected to occur
With our limited current knowledge on the design, cost, and performance
of the concrete block roadways, it would be inadvisable to recommend
large scale road construction in the pond. A more reasonable approach
would be to construct roads in the forebay, where the need is most
critical, and to use the forebay roads as a test facility to evaluate
their use in the pond.
Another approach that appears attractive is the use of precast reinforced
concrete "logs" used in the construction of retaining walls. The logs,
which are readily available as 5-1/2" x 5-1/2" x 48" blocks, could be
arranged in an open mesh which is held together by cables passing
through each log. Figure D-4 shows the proposed arrangement. Logs
with holes in their sides would be strung on the cables which would be
enclosed in the forebay or pond. After all the logs are installed, a
steel backplate would be inserted and the cables would be tightened.
When a wheeled vehicle traveled over the roadway, the mat would be
somewhat flexible. According to Figure D-4, each linear foot of
roadbed would require about seven square feet of block. At $2/square
foot, the roadway would cost about $14/linear foot; thus, a roadway in
the forebay would cost about $3500-$4000.
SMALL PUMP/DREDGE
It has been noted that an appreciable amount of sediment is expected
to be deposited in the forebay, where it could be easily removed after
dewatering by loaders operating from "underwater" roads. It is also
expected that most of the sediment in the pond proper will be located
154
-------
Anchors
Front Retaining Plate
O X . __Q
....
^—-^ - Tension
Posts
Backplate
Figure D-4. Underwater Concrete "Log" Road
155
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at the upper end because of the relatively large surface area available.
Thus, it may be possible to devise an economical method of periodically
removing material from the upper end of the pond to the forebay, and
thus minimizing the need for cleaning the entire pond. This function
could be served by a small floating dredge that would pump to the fore-
bay and would operate in the upper area of the pond. Because the fore-
bay will be designed to remove almost all of the coarse material, most
of the material in the pond should be of relatively small particle size.
Thus, it should be possible to remove the sediment without the use of
a mechanical cutting head such as that used by conventional dredges.
As mentioned in a previous section, small dredges are not available
for rental. It should not be difficult, however, to assemble readily
available components in a small equipment package that could be use'd
to test the hypothesis that significant amounts of material could be
pumped from the upper end of the pond without elaborate mechanical
cutting equipment. The heart of this system will, of course, be the
pump. Diaphragm pumps such as that manufactured by the Edson
Corporation of New Bedford, Massachusetts, have been used for light
duty dredging in boat yards and marinas. Their largest pump, 4" intake
- 130 gpm, could be easily mounted on a raft. Flexible intake hoses
would connect the pump to a rigid on-shore PVC pipeline leading to the
forebay. The raft would be held in place by steel pipe "spuds" dropped
from two corners. The intake probe would be guided manually by an
operator aboard the raft.. The package would, therefore, include a
heavy duty gasline-powered diaphragm pump, flexible intake and
discharge piping, a dredging probe, a raft, and several floats.
Approximate costs for assembling the equipment package and operation
for four weeks are estimated at about $3500. This estimate must be
considered preliminary in that little is known about the labor required
to remove a given amount of sediment with this system; twenty man-
days has been assumed.
156
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APPENDIX E
LABORATORY SEDIMENT STUDIES
EFFECT OF CHEMICAL ADDITIVES
Five columns, each filled with three feet of sediment above one foot of
filter sand and nine inches of gravel, were tested. The columns were
treated with the following chemicals:
Column 1 Control
Column 2 Dow A21 250 ppm
Column 3 Hercufloc 6217 250 ppm
Column 4 Hercufloc 6175 250 ppm
Column 5 Dow N17 250 pp'm,
A filtration test was operated for three days and the amount of water
drained was recorded.' The test was abandoned at the end of the third
day due to the unsatisfactory results. All chemical treatments failedto
significantly improve drainability.
EFFECT OF SEDIMENT DEPTHS
Five columns each filled with nine inches gravel and 12 inches of filter
sand were filled with the following amounts of sediment:
Column 1 6 inches
Column 2 12 inches
Column 3 18 inches
Column 4 24 inches
Column 5 36 inches
The water drained from each column was recorded. The test was con-
ducted for 56 days. Results of the test are presented in Table E-l.
157
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TABLE E-l. SEDIMENT DEWATER TEST BY VARYING DEPTH OF COLUMN
Ol
CO
Unit No
.
Bed Depth
Time Readin/
6/15 14:30
6/16 9:00
6/17 9:30
6/18 9:45
6/21 9:00
6/22 9:30
6/25 9:30
6/28 14:00
6/30 10:00
7/8 14:00
7/12 13:30
7/15 15:00
7/20 15:00
7/29 11:00
8/11 15:30
Dewater Rate K
Dewater Rate K
Total Water W0
Total Drainable
Residue Water
1 Pays
0
0.77
1.80
2. 80
5.77
6.77
9.77
13.00
14.80
23.00
27.00
30.00
35.00
43.80
56.00
j @t<3.5
2@t>3.5
Water*
1
6 in.
mlH0O 7oH,O
' *
Drained Remain
0
40
75
95
122
129
142
150
150
154
155
155
155
156
...
100
75
53
41
24
19
11
5
5
3
2
2
2
1.4
0. 1333
0.0588
500
158
340
2
1 ft
mlH0O %H0O
Z " *
Drained Remain
0
70
110
145
179
188
207
230
238
257
262
267
268
273
275
0.0875
0.0281
1000
312
688
100
78
65
54
43
40
34
26
24
18
16
14
14
12
--
3
1 ft 6 in.
mlH,O %H,O
i & +
Drained Remain
0
50
125
155
207
220
250
280
292
348
366
376
388
401
418
100
89
73
66.5
55.5
52.5
46
40
37
25
21
19
16.5
14
0.0588
0.0189
1500
468
1032
4
2 ft
mlH,,O %H,O
*
Drained Remain
0
75
130
165
233
247
286
316
331
388
415
432
452
470
480
0.0500
0.0124
2000
624
1376
100
83
79
67
61
60
54
49
47
37
33
30
27
25
--
5
3 ft
ml H,O % H,O
* *
Drained Remain
0
90
150
200
270
288
335
374
394
468
493
515
554
618
672
100
90.4
84
79
71
69
64
60
58
50
47
45
41
34
—
0.0377
0.0082
3000
936
2064
% Drainable Water Remaining at t Days.
Determined Based on Column 1 Test.
-------
VACUUM FILTRATION
Small samples of sediment (200 m4) were treated with various chemical
additives ranging from zero to several thousand parts per million. The
treated samples were filtered by a Buchner Funnel under a vacuum of
20 inches of mercury. The filtrate using Whitman #4 filter paper was
measured at various intervals. The rate of filtration as measured by
the fraction of the water drained was plotted on semilog graph paper.
The efficiency of the filtration test was determined by the time required
to remove 30 percent of the initial moisture. The efficiency of each
test was compared with control tests under similar test conditions.
The test results are summarized in Table E-2.
The chemical additives tested included three inorganic coagulants,
12 organic polymers supplied by Dow and Hercules, three combined
organic and inorganic coagulants and four physical agents. The results
indicated that up to 66 percent improvement of removal rate can be
obtained; however, extremely high dosing rates must be applied.
159
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TABLE E-2. VACUUM FILTRATION OF SEDIMENT SAMPLE
Time (min) Required to Remove
30% Moisture from Sample at Opt. Dosage
Additives Tested
Alk(S04)212H2O
FeCl36H2O
FeSO47H20
Dow C31
Dow 032
0°TA2i , ,
Hercufloc 8586
Hercufloc 6217
Hercufloc 6175
Hercufloc 8634
Dow A22
Dow Nj}
Dow Ni2
Dow Nj 7
Dow A23
FeCls6H2P* +
Hercufloc 6217
Hercufloc 6175
FeCl36H2O* +
Dow A23
Sand
Sawdust
Incinerator Ash
Crushed Foam
Dosing Rate
mg/4
75-2800
50-3000
67-3120
10-500
10-500
20-1000
5-150
8-250
8-250
8-250
50-1500
38-750
25-750
25-750
25-500
50-400
50-400
50-400
5-40% Vol.
2-20% Vol.
5-40% Vol.
5-30% Vol.
Control
60 min
72 min
75 min
50 min
80 min
83 min
75 min
75 min
70 min
80 min
90 min
75 min
75 min
100 min
105 min
85 min
90 min
100 min
55 min
120 min
100 min
125 min
Opt.
Run
. 60 min.
. 39 min
60 min
50 min
52 min
28 min
57 min
37 min
40 min
65 min
40 min
40 min
28 min
38 min
43 min
53 min
42 min
43 min
55 min
95 rnin
100 min
95 min
Improve-
ment
0%
46%
20%
0%
35%
66%
37%
51%
43%
19%
56%
47%
63%
62%
59%
38%
53%
57%
0%
21%
0%
24%
Opt.
Dosage
3000
3120
--
500
1000
150
250
250
250
1500
750
750
750
500
400
400
400
--
20%
--
30%
'FeCl3 6H2O applied at 500 mg/4
160
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APPENDIX F
FIELD STUDIES FOR EVALUATION OF SEDIMENT
DRYING, CONDITIONING, AND DISPOSAL
OBJECTIVES
The objectives of the field studies were:
1. To demonstrate and evaluate the use of sand and gravel
drying bed bottoms
2. To demonstrate and evaluate mechanical/physical handling
of drying sediment
3. To investigate various mixtures of sediment and other
additives
4. To demonstrate the effectiveness of various mixtures on test
grass plots
METHODOLOGY
Demonstration tests were conducted on four drying beds illustrated
in Figure F-l. The beds had gravel and sand bottoms consisting of
12 inches of gravel (1/8 to 3/4inches) overlain by a 12-inch layer of
sand (effective size 0.3 — 0. 75 mm; uniformity coefficient not over 4. 0).
Provisions were made for carrying away water drained from the
sediment. The drying beds were loaded directly from the trucks. Core
samples were collected for moisture analysis; drained water samples
were collected for physical and chemical analysis at various intervals.
Sketches of the demonstration beds are shown in Figures F-2, F-3, and
F-4. The drying beds were further divided into four plots each.
161
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OS
to
86'
— id —
45.
'/ I M I I I I I
B
M
i
• "»
«, Drainage
Ditch
1" = 12'
Figure F-l. Demonstration Drying Beds - Plan View
-------
\
, y
Sediment Fill
Sand
V *-
• Gravel
~—-——. 0
1" = 4'
Figure F-2. Section B-B, Demonstration Drying Beds
163
-------
CT>
Earth from
Excavation
. ' .'• Sand
'Gravel
/••;••• .'-:•; ;. '. ' '-/ Grade
/
4"D. Drain Pipe
1/20
1" = 4'
-440
435
-.430
Figure F-3. Section A-A, Demonstration Drying Beds
-------
Oi
N
i
.1" = 25
o
o
o
in
CO
W
o
IO
o
in
TO
W
o
o
Ift
03
W
in
OD
W
SM 510250
N 510200
N 510150
Conventional Sediment
Drying Facility
N 510100
Figure F-4. Location of Demonstration Drying Beds
-------
Several conditioning materials were added to the sediment according
to the following pattern:
Bed 1
Bed 2
Plot 1 - Sludge
Plot 2 - Fly ash
Plot 3 - Woodchips
Plot 4 - Control
Plot 5 - Sludge
Plot 6 - Fertilizer 10-10-10
Plot 7 - Woodchips
Plot 8 - Control
Bed 3
Bed 4
Plot 9 - Fly ash
Plot 10 - Sludge
Plot 11 - Control
Plot 12 - Lime
Plot 13 - Fly ash
Plot 14 - Fertilizer 10-10-10
Plot 15 - Control
Plot 16 - Lime
Equal amounts of seed were sown in each plot. Observations were made
over a period of eight weeks on plant behavior and sediment characteristics.
Application Rates of Additives
Sludge
Fly ash
Woodchips -
Lime
Fertilizer -
5 Ibs/sq ft
4 Ibs/sq ft
5 Ibs/sq ft
0.4 Ibs/sq ft
0.4 Ibs/sq ft
Results and Discoveries
The parameters considered to be the main determinants in evaluation of
the studies were:
(1) Germination period
(2) Plant cover and density
(3) Plant quality
(4) Drainage water quality
166
-------
(5) Physical conditions of sediment upon application of
conditioning material
(6) Drainability
Germination took place on most plots eight days after seeding except
for fly ash plots where initial germination was observed after 12 days.
The degree of coverage was greatest in the sludge plots, follwed by
lime, control, fertilizer, and woodchips. Plant coverage in the fly
ash plots was very sparse, but after another week coverage improved.
Plant quality was determined by the color of the leaves, the stability
of the leaves, and the rate of growth. All the above factors were
considered during the growth period. The color of the plants varied
from dark green on the fertilizer and sludge plots to light green in the
control plots of pond sediments. Forebay sediment control plots had
better quality plants than pond sediments. Grass on fertilizer and
sludge plots grew faster than the others, and plants on woodchip plots
showed slowest growth. This can be attributed to the availability of
nitrogen in sludge and fertilizer. The most prominent cause of
deterioration in plant quality was nutrient deficiency. This was well
evidenced in the control and woodchip plots.
The conclusions drawn from these studies are:
(1) Sediment,when properly mixed with both organic material
and inorganic chemicals, supported vigorous plant growth.
(2) The drainability of fine sediment was improved by addition
of organic material.
(3) The most effective additives tested were sludge, fertilizer,
and fly ash.
(4) Unconditioned sediment plots showed signs of nutrient
deficiency.
167
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SELECTED WATLR }. Report
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
J. Accession No.
^- Title s. Report Date
JOINT CONSTRUCTION SEDIMENT CONTROL PROJECT 6'
8. Performing Organization
7. Author(s) Becker, Burton C., Emerson, Dwight B, and Report No.
Nawrocki, Michael A.
9. Organization Hittman Associates, Inc.
9190 Red Branch Road "' Contract/Grant No.
Columbia, Maryland 21045
10. Project No.
15030 FMZ
Under contract to 13. Type of Report and
The Water Resources Administration, State of Maryland Period Covered
12. Sponsoring Organization
15. Supplementary Notes
Environmental Protection Agency report number, EPA-660/2-73-035, April 1974.
16. Abstract
During the period of this demonstration, a natural and agricultural region
is being converted to an urban community. This project consists of (1) the
implementation, demonstration, and evaluation of erosion control practices:
(2) the construction, operation, and demonstration of the use of a stormwater
retention pond for the control of stormwater pollution; and (3) the construction,
operation, and maintenance of methods for handling, drying, conditioning, and
disposing of sediment; In addition, a gaging and sampling program was conducted
as part of this project to determine the effects of urbanization on the hydrology
and water quality of natural areas. This project was conducted in the Village of
Long Reach, Columbia, Maryland.
This report was submitted in fulfillment of Grant No. 15030 FMZ by the
Water Resources Administration, State of Maryland, under the partial
sponsorship of the Environmental Protection Agency. Work was completed as
of June 1973.
I7a. Descriptors *Aquatic environment, ^'Construction, ^'Demonstration Watersheds,
*Erosion Control, * Rainfall-runoff relationship, *Sedimentation, *Urbanization,
^Watershed, Biology, Channel morphology, control, costs, dam, ecology, forebays,
gaging stations, hydraulics, hydrology, lentic environment, lotic environment,
mathematical modejLs, maintenance, monitoring, peak discharge, pond, revegetation
runoff, suspended load, trees, turbidity, utilities, water quality, weirs.
17b. Identifiers
^Guidelines, ^Columbia, Maryland, grade control, recycled glass, recycled
sediment, return frequency, sediment basins, site evaluation, soil loss surveys,
woodland development.
17C.COWRR Field & Group 02E, 02H, 02J, 04A, 04C, 04D; 05C 05D
18. Availability 19. Security Class.
(Report)
20. Security Class,
(rage)'
21. No. of Send To:
Pages
Prirfi WATrlR liriSOURCF.S SCI ENT I F1C INT ORM A1 ION CRN 7 FH
1 j;tc U.S. DEPARTMENT OF THL INTCTtlOH
WASHING ION. D. C. 20240
Abstractor Burton C. Becker ^institution Hittrnan Associates, Inc.
WRSICI02(REV JUNtl97l) GPO -t
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