20081342 Ver 1_More Info Received_20090417

Soil & Environmental Consultants, PA
11010 Raven Ridge Road • Raleigh, North Carolina 27614 • Phone: [phone] • Fax: [phone]
www.SandEC.com
April 17, 2009
S&EC Project # 5931.W4
DWQ No. # 08-1342
Action ID SAW-2008-0259
US Arm Corps of Engineers ` ,") WAT QUA f rili TL? "' 0,2 AN' D? S!
Raleigh Regulatory Field Office
Attn: Mr. James Lastinger
3331 Heritage Trade Drive, Suite 105
Wake Forest, NC 27587
Re: Reply to the US Army Corps of Engineers' 10/17/08 and 11/26/08 requests for additional information
Franklin County Pond, Individual Permit and Water Quality Certification
Franklin County, North Carolina'
Dear Mr. Lastinger:
This letter is in response to your letter dated October 17, 2008 and your email dated November 26, 2008
which requested additional information for the proposed Franklin County Pond. The following restates
your questions/comments and is then followed by our response.
Additional Information Requested on October 17, 2008
1. Please provide information on avoidance and minimization, primarily through the
possibility of using existing ponds on site, the possibility of off-line pond
construction, reduction of the size of the proposed pond, and the potential to either
purchase or lease land with existing ponds adjacent to the applicants property.
In their "Request for More Information Letter" dated September 24, 2008, the NC Division of Water
Quality (DWQ) raised the same questions regarding avoidance and minimization. Our response, dated
October 23, 2008 addressed this concern in detail. S&EC provided the USACE with a "courtesy copy" of
that correspondence (see responses to DWQ concerns Nos. 1 and 2).
In an email dated 10/3/08 (copy attached) to the USACE, the NC Wildlife Resource Commission (NC
WRC) biologist stated that "Quality largemouth bass can be established in ponds around S acres. "
Accordingly, the existing pond on the property, which is approximately 0.52 acres in size, would not be
sufficient in size (see attached Alternate Pond Map). In addition, based on the topography, the maximum
the existing pond could be expanded to is 1.3 acres, which is still of inadequate size for the proposed
purpose. The available drainage area is also inadequate in size to support a 1.3 acre pond based on NRCS
design criteria (discussed in more detail below). Additionally, all experts consulted raised concerns about
low dissolved oxygen (DO) levels in small (1 acre) ponds during the summer months.
Ponds located on adjacent properties have similar size and drainage area inadequacies as discussed above.
The adjacent properties also have existing homes on them and/or the ponds are used primarily for livestock
watering and therefore are not available for lease or purchase. For these reasons, it is not practical to look
offsite for additional pond settings.
We have reviewed other possible locations for the proposed pond on the subject property (see attached
Alternate Pond Map) and have demonstrated not only the possible alternate pond sizes, but have also
Charlotte Office:
248 LePhillip Court Greensboro Office:
Concord, NC 28025 3817-E Lawndale Drive
Greensboro, NC 27455
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
included the required drainage areas necessary to supply the pond with a constant water level to maintain
water quality per the NRCS manual Ponds - Planning, Design and Construction " Agriculture Handbook
590 (see attached). The NRCS Manual indicates that at least 3 acres of drainage area is required for each
acre/ft of water in a pond in this area of the United States (see Figure 11, page 10 from the NRCS Manual).
Neither of the other possible pond locations (Alternate 1 nor Alternate 2) have adequate drainage area td
support the surface area of the pond.
2. Please provide information regarding purpose and need pertaining to pond size for
the use intended for the construction of a pond designed for recreational largemouth
bass fishing.
Several experts in the area of pond management were consulted regarding the minimum, viable pond size
for large mouth bass management. Based upon our discussions with them, the consensus is that a pond of
between 5 to 10 acres is the minimum size that is feasible to successfully manage large mouth bass (see
attached 10/1/08 email from Mr. Russell A. Wright, Extension Specialist, Associate Professor of Fisheries,
Department of Fisheries and Allied Aquacultures, Auburn University). Mr. Wright suggested in his
correspondence with us that approximately 8 to 10 acres was the minimum, practicable size for a large
mouth bass pond. Mr. Mitchell Morton, Manager/Fisheries Division, Fisheries Biologist with Foster Lake
and Pond Management suggested that a pond of at least 5 to 8 acres is the minimum viable pond size in his
10/7/08 letter (see attached letter and bio). NC WRC also concluded that managing a pond of less than 5
acres for bass will be difficult. Based upon this data, we began to determine if any areas existed on the
property that could provide a pond site of 5 acres or more.
Several pond layouts were considered for the project and discussed in the original application but we will
recap that discussion here; the proposed preferred layout (Fig. 7, Preferred Alternative Pond 3)
demonstrates the second to least amount of stream and least amount of wetland impact of those proposed in
the original application. As demonstrated by the different pond layouts provided in the initial application
submittal (see attached Fig. 7), the stream and wetland impacts varied from 1,951 linear feet to 5,700 linear
feet and 0.40 acres to 5 acres respectively. Alternative Plan Pond 1, while similar in impacts to the
Preferred Alternative Pond 3, would cause offsite flooding during large storm events and therefore, was not
a feasible alternative. Alternative Pond Plans 2 and 4 resulted in pond surface areas larger than the
preferred alternative and resulted in greater stream and wetland impacts than the preferred alternative. So,
of the original pond sites all were greater in size than 5 acres and Preferred Alternative Plan Pond 3 caused
the least impact to jurisdictional waters. Therefore, of the original proposed pond options, Preferred
Alternative Plan Pond 3 is the preferred choice from a minimization and avoidance criteria.
In order to address concerns raised by DWQ and NC WRC regarding other possible sites, we also
considered any areas that could result in a pond surface area with a minimum of 5 acres since all "experts"
consulted have agreed that 5 acres or larger is the minimum pond size feasible for the proposed use (the
range was 5 to 10 acres depending on which expert you asked). Only 2 other locations on the property
could topographically support a 5 acre or larger pond (see attached Alternate Pond Map). Other drainage
areas on site were not considered because they are either too small to support a pond for large mouth bass
or too small to keep at near constant water level to maintain water quality in the proposed pond.
We have reviewed other possible locations for the proposed pond on the subject property (see attached
Alternate Pond Map), have shown the proposed alternate pond sizes, and have also included the required
drainage areas necessary to supply the pond with a constant water level to maintain water quality. As can
clearly be seen in the attached Alternate Pond Map, none of the proposed alternate locations (Alternate 1
and 2) has a large enough drainage area to support those pond alternatives. We have also demonstrated that
the Preferred Alternative Plan Pond 3 is the "least environmentally damaging practical alternative" based
upon the above supplied data from "experts" in the field of fisheries management. If the agencies would
like for us to evaluate other possible dam locations, we will be glad to do so if they are identified on the
map for us. However, based upon the above information, we do not believe any other feasible sites exist on
the property.
3. Please provide information pertaining to other possible on-site mitigation
opportunities as discussed at our site meeting on September 18, 2008, and a
compensatory mitigation plan. Please be reminded that no Department of the Army
(DA) permit can be authorized without the submittal, review and approval of final
compensatory mitigation plan.
Per our January 5, 2009 office meeting, we provided a compensatory mitigation plan that proposes to
preserve and enhance 10,238 linear feet of perennial streams (4.7:1 ratio), 3,530 linear feet of intermittent
streams (1.6:1 ratio) and 4.32 acres of riparian wetlands (13.4: 1 ratio) on site through the use of fencing to
keep the livestock, which currently has access to those streams and wetlands, out of the them. It is
important to note that the applicant will also be recording a conservation declaration area (30 foot or 50
foot dependant on the stream as determined by the USACE in February 2009) on the streams and wetlands
in question. Please see the attached Mitigation Sketch Map, dated February 11, 2009, which was
previously approved by your office as sufficient to satisfy the compensatory mitigation plan requirement.
4. Indicate if any fill is expected within a FEMA designated floodplain and measures
needed to ameliorate those impacts.
The proposed pond will have permanent fill associated with the pond dam within a FEMA designated
floodplain. Proper permits will be obtained by the applicant from the State Floodplain Mapping Program
through the local flood plain administrator once the USACE and DWQ Approvals are secured. The dam
will be properly designed to ensure that it can safely convey the 100-year event through its primary and/or
emergencies spillways. A flood study and letter of map revision will also be prepared to show how the
proposed dam will affect the upstream and downstream properties.
Flood attenuation that was provided in the section of floodplain that is lost in the dam construction will be
replaced by the storage provided in the proposed pond. Floodplain habitat and wildlife passage that was
previously provided in the floodplain will still be available along the edge of the proposed pond.
5. Please provide information concerning effects on threatened and endangered species
in the project area pursuant to the Endangered Species Act of 1973, particularly the
dwarf wedge mussel.
Our initial Individual Permit Application submittal discussed Fish & Wildlife Values in Section 5.16 of the
Supplemental Information documentation. The dwarf wedge mussel inhabits creek and river areas with a
slow to moderate current and a sand, gravel, or muddy bottom within the Tar and Neuse drainages, mainly
near the Fall Line. Potential suitable Habitat is located on the tributary to Cedar Creek within proposed
project boundaries. NCNHP documentation of this species occurs in Cedar Creek approximately 1-mile
northwest (i.e. upstream) of the 400+ acre property and the proposed project boundary (see Figure 10). As
this occurrence is upstream of the proposed project site, it is not anticipated that the proposed Franklin
County Pond will have any effect on the documented occurrence. It should also be noted that the
Franklinton Waste Water Treatment Plant (WWTP) discharge is situated between the proposed project site
and the documented occurrence for the Dwarf Wedge Mussel. It is commonly accepted that endangered
species occurrences are rare immediately downstream of a Waste Water Treatment Plant. A NCWR
representative accompanied us on our site and office meetings with you and we believe she has concurred
that the proposed project is unlikely to adversely affect any endangered or threatened species, particularly
considering the mitigation and pond design criteria proposed.
Additional Information Requested via electronic mail (e-mail) on November 26, 2008
1. [Additional information we would like to have regarding) the design of the dam
regarding the heights of all the dams used in the alternatives analysis in the original
application.
All dams considered, except the largest alternative that was rejected, were below 15 feet in height. This was
not done to avoid dam safety regulation but rather due to the topography and property lines onsite. The
preferred alternative may still be deemed to require approval by the NC Dam Safety Act. The applicant
intends to design the dam in accordance with the criteria of the Dam Safety Act even if no actual approval
from the NC Division of Land Resources is ultimately required.
2. [Additional information we would like to have regarding) the heights in the
additional information that was sent to DWQ.
In the case of the two larger pond alternatives, the dam height would be approximately 24 feet.
3. [Additional information we would like to have regarding] the height of the dam in
your preferred alternative.
The preferred alternative dam height is approximately 14.5 feet.
4. [Additional information we would like to have regarding] the impacts associated
with the dissipater pad on the back side of the dam.
The original Individual Permit application demonstrated 128 linear feet of permanent perennial stream
impact associated with the proposed dam fill. Included in the length of stream impact (see Fig. 5A-Inset 1,
attached) is the proposed stream impact associated with the necessary dissipation devices. The impact
exhibit shows the dam fill impact to be 105 linear feet and the rip rap dissipation pad to be 23 linear feet.
Therefore, the total permanent stream impact for the dam and the dissipation pad will be 128 linear feet.
5. [Additional information we would like to have regarding] lowering the dam height.
This option is not a possibility because it would not allow for sufficient pond depth to prevent nuisance
weed and algal growth (as we described in our response to NC DWQ dated October 23, 2008).
6. [Additional information we would like to have regarding] moving the dam to another
location on the stream or moving the dam to another location on a different stream
to allow for a smaller pond.
As we discussed in our previous response to NC DWQ, as well as during our field and office meetings with
USACE staff, there are no other sites on the property that will result in the minimum 5 acre pond that the
experts we consulted acknowledge is needed for a recreational large mouth bass pond.
7. [Additional information we would like to have regarding] a dam with less impacts as
well as eliminating the possibility of off-site flooding (this would then allow for
alternative one, which has less impacts to be considered).
Alternative Pond Plan 1 (aka Dam 1) while it does have 214 linear feet less permanent stream impact
overall, it ultimately proposes more permanent wetland impacts. As stated above, lowering the dam height
will not allow for sufficient pond depth to prevent nuisance weed and algal growth (as we described in our
response to NC DWQ dated October 23, 2008). There will also still be the possibility of off-site flooding
during large storm events. This alternative was not chosen as the preferred alternative because of the
greater amount of permanent wetland impacts in addition to the potential for offsite flooding.
8. [Additional information we would like to have regarding] impacts associated with
the construction of the dam (i.e. temporary stream impacts associated with de-
watering, etc.).
The applicant plans to place a temporary pipe within the foot print of the proposed dam to route water
during construction under/thru the dam, the pipe will remain open during construction and while the
principal spillway is constructed. The temporary pipe will be closed when the construction is complete and
the low flow orifice in the principal spillway is functional. The principal spillway will be constructed such
that the outlet will discharge into the stream at its natural location downstream of the toe of the proposed
dam. We are open to any suggestions the agencies have as far as alternative methods of construction. In
fact, NCWR staff mentioned some information they had in their files that may be of use to us. We would be
happy to have that information and will be glad to implement alternative construction techniques that the
agencies may suggest.
[Additional information we would like to have regarding] mitigation. After doing
some rough calculations the minimum amount that we would require for mitigation
from enhancement is about 6,495 linear feet [of stream]. Your proposal only
suggests about 6,2001inearfeet which is not adequate to offset impacts that would
be incurred from the construction of this pond. The amount continues to climb to a
maximum of 21,650 linear feet of stream.
Per our January 5, 2009 office meeting, we provided a compensatory mitigation plan that proposes to
preserve and enhance 10,238 linear feet of perennial streams (4.7:1 ratio), 3,530 linear feet of intermittent
streams (1.6:1 ratio) and 4.32 acres of riparian wetlands (13.4: 1 ratio) on site through the use of fencing to
keep the livestock, which currently has access to those streams and wetlands, out of the them. It is
important to note that the applicant will also be recording a conservation declaration area (30 foot or 50
foot dependant on the stream as determined by the USACE in February 2009) on the streams and wetlands
in question. Please see the attached Mitigation Sketch Map, dated February 11, 2009, which was
previously approved by your office as sufficient to satisfy the compensatory mitigation plan requirement.
Please feel free to contact me if any further explanation is necessary.
Sincerely,
Nicole J. Thomson
Regulatory Specialist
Attachments: 3 copies of Response letter
3 copies of Fig. 5A - Inset 1 (revised)
3 copies of Fig. 7 from original IP application submittal
3 copies of Alternate Pond Map
3 copies of NRCS manual Ponds - Planning, Design and Construction " Agriculture Handbook 590
3 copies of NC WRC 10/3/08 email correspondence to USACE
3 copies of Mr. Russell A. Wright 10/1/08 email correspondence to S&EC
3 copies of Mr. Russell A. Wright's Curriculum Vitae
3 copies of Mr. Mitchell Morton 10/7/08 letter to S&EC
3 copies of Mr. Mitchell Morton's Resume
3 copies of Lake Size, Aquatic Macrophytes, and Largemouth Bass Abundance in Florida Lakes: A reply
3 copies of the final approved Mitigation Sketch Map (dated Feb. 11, 2009)
Cc: Mr. Ian McMillan, NC DWQ
Mr. Carlton Midyette
MIDYETTE FARM
FRANKLIN CO. POND
FRANKLIN COUNTY, NC
e '1 WETLAND IMPACT:
530SF/0.012AC
STREAM IMPACT:
PROPOSED DAM DISSIPATER PAD
23 LF
556SF/0.013AC
; as
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GRAPHIC SCALE STREWIMPACT:
1 50' EARTHEN FILL,,—
0 50
105-LF
3344 SF-l`o.077 AC DAM-FILL IMPACTS
FIG. 5A - INSET 1
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ALTERNATIVE PLAN
POND 1 - 311,361 SF (7.15 AC) Q
STREAM IMPACTS: 1,951 LF O
C
WETLAND IMPACTS: 17,637 SF (0.40 AC)
ALTERNATIVE PLAN
POND 2 - 514,571 SF (11.81 AC)
STREAM IMPACTS: 2,394 LF
WETLAND IMPACTS: 23,180 SF (0.53 AC)

PREFERRED
ALTERNATIVE PLAN
i 1 POND 3 - 457,514 SF (10.50 AC)

z STREAM IMPACTS: 2,165 LF
j WETLAND IMPACTS: 14,500 SF (0.33 AC) M
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ALTERNATIVE PLAN ?
POND 4 - 1,528,188 SF (35.08 AC)
STREAM IMPACTS: 5,700 LF
WETLAND IMPACTS: 217,713 SF (4.99 AC) M

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GRAPHIC SCALE i
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PROPOSED POND PLAN
FIG
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Project No.
5931.W4 Scale:
r=450'
MIDYETTE FARM
SOURCE:
Project Mgr. Drawn By: FRANKLIN CO. POND 11010 Raven Ridge Rd.
NT MM Raleigh, NC 27614
0
FRANKLIN COUNTY, NC 919-846-5900
Date: 08@8/08
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Preface
This handbook describes the requirements for building a pond. It is useful
to the landowner for general information and serves as a reference for the
engineer, technician, and contractor.
In fulfilling their obligation to protect the lives and property of citizens,
most states and many other government entities have laws, rules, and
regulations governing the installation of ponds. Those responsible for
planning and designing ponds must comply with all such laws and regula-
tions. The owner is responsible for obtaining permits, performing necessary
maintenance, and having the required safety inspections made.
Acknowledgments
The first version of this handbook was prepared under the guidance of
Ronald W. Tuttle, national landscape architect for the USDA, Natural
Resources Conservation Service (NRCS), and Gene Highfill, national
agricultural engineer (retired), NRCS, Washington, DC.
This version of the handbook was prepared by Clifton Deal, soil mechanic
engineer, NRCS Portland, Oregon; Jerry Edwards, hydraulic engineer
(retired), NRCS, Columbia, Missouri; Neil Pellmann, agricultural engineer,
NRCS, Columbia, Missouri; Ronald W. Tuttle; and under the guidance of
Donald Woodward, national hydrologist, NRCS, Washington, DC.
The appendixes material was originally prepared for Landscape Architec-
ture Note 2-Landscape Design: Ponds by Gary Wells, landscape architect,
NRCS, Lincoln, Nebraska.
Mary R. Mattinson, editor; Lovell S. Glasscock, editor; John D.
Massey, visual information specialist; and Wendy R. Pierce, illustrator;
NRCS, Fort Worth, Texas, provided valuable assistance in preparing the
document for publishing.
Agriculture Handbook 590 Ponds Planning, Design,
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II
Contents Introduction 1
Water needs 2
Livestock ............................................................................................................ 2
Irrigation ............................................................................................................ 3
Fish production ................................................................................................. 3
Field and orchard spraying .............................................................................. 4
Fire protection .................................................................................................. 4
Recreation .......................................................................................................... 6
Waterfowl and other wildlife ........................................................................... 6
Landscape quality ............................................................................................. 6
Multiple purposes ............................................................................................. 8
Preliminary investigations 9
General considerations ................................................................................... . 9
Area adequacy of the drainage ....................................................................... . 9
Minimum pond depth ..................................................................................... 10
Drainage area protection ............................................................................... 11
Pond capacity .................................................................................................. 12
Landscape evaluation ..................................................................................... 12
Estimating storm runoff 13
Hydrologic groupings of soils ........................................................................ 13
Runoff curve numbers .................................................................................... 13
Volume of storm runoff .................................................................................. 18
Rainfall amounts and expected frequency .................................................. 19
Rainfall distribution ........................................................................................ 19
Peak discharge rate ........................................................................................ 20
Time of concentration .................................................................................... 20
Average watershed slope ............................................................................... 21
Flow length ...................................................................................................... 21
la lP ratio .......................................................................................................... 21
Estimating peak discharge rates ................................................................... 22
Site surveys 24
iii
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Embankment ponds 24
Detailed soils investigation ............................................................................ 24
Spillway requirements .................................................................................... 26
Pipes through the dam ................................................................................... 36
Planning an earthfill dam ............................................................................... 45
Staking for construction ................................................................................ 53
Building the pond ............................................................................................ 53
Excavated ponds 57
Soils .................................................................................................................. 57
Spillway and inlet requirements .................................................................... 58
Planning the pond ........................................................................................... 58
Building the pond ............................................................................................ 61
Sealing the pond 62
Compaction ..................................................................................................... 62
Clay blankets ................................................................................................... 63
Bentonite .......................................................................................................... 63
Chemical additives .......................................................................................... 64
Waterproof linings .......................................................................................... 65
Establishing vegetation 66
Protecting the pond ........................................................................................ 66
Wave action ..................................................................................................... 66
Livestock .......................................................................................................... 67
Operating and maintaining the pond 68
Pond safety 69
Before construction ........................................................................................ 69
During construction ........................................................................................ 69
After completion ............................................................................................. 69
References 70
Glossary 71
Appendixes 75
Appendix A: Estimating the Volume of an Excavated Pond ..................... 75
Appendix B: Flood-Tolerant Native Trees and Shrubs .............................. 79
iv
Agriculture Handbook 590 Ponds-Planning, Design, Construction

Tables Table 1 Runoff curve numbers for urban areas 14
Table 2 Runoff curve numbers for agricultural lands 15
Table 3 Runoff curve numbers for other agricultural lands 16
Table 4 Runoff curve numbers for and and semiarid rangelands 17
Table 5 Runoff depth, in inches 18
Table 6
Table 7 Ia values for runoff curve numbers
Minimum spillway design storm 21
27
Table 8 Permissible velocity for vegetated spillways 28
Table 9 Guide to selection of vegetal retardance 28
Table 10 Hp discharge and velocities for natural vegetated
spillways with 3:1 end slope (Z) 30
Table 11 Depth of flow (H) and slope range at retardance
values for various discharges, velocities, and crest lengths 34
Table 12 Discharge values for smooth pipe drop inlets 38
Table 13 Discharge values for corrugated metal pipe drop inlets 38
Table 14 Minimum head, h (ft), required above the invert of 41
hood inlets to provide full flow, Q (ft3/s), for various sizes of
smooth pipe and values of total head, H
Table 15

Table 16 Minimum head, h (ft), required above the invert of
hood inlets to provide full flow, Q (ft3/s), for various
sizes of corrugated pipe and values of total head, H
Recommended side slopes for earth dams 42

46
Table 17 End areas in square feet of embankment sections
for different side slopes and top widths 48
Table 18 Volume of material needed for the earthfill 51
V
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Figures Figure 1 Typical embankment and reservoir 1
Figure 2 This pond supplies water to a stockwater trough used by 2
cattle in nearby grazing area
Figure 3 Water is pumped out of this pond for irrigation 3
Figure 4 A pond stocked with fish can provide recreation as 4
well as profit
Figure 5 A dry hydrant is needed when a pond is close enough 5
to a home or barn to furnish water for fire fighting
Figure 6 Details of a dry hydrant installation 5
Figure 7 Ponds are often used for private as well as 6
public recreation
Figure 8 Waterfowl use ponds as breeding, feeding, 7
watering places, and as resting places during migration
Figure 9 The shoreline of a well-designed pond is protected 7
from erosion by the addition of stone. Such a pond,
reflecting nearby trees, increases the value of
the surrounding land
Figure 10 This pond, which served as a sediment basin while 8
homes in the background were being constructed,
now adds variety and value to the community
Figure 11 A guide for estimating the approximate size of a 10
drainage area (in acres) required for each acre-foot
of storage in an embankment or excavated pond
Figure 12 Recommended minimum depth of water for ponds 11
in the United States
Figure 13 Land with permanent vegetation makes the 12
most desirable drainage area
Figure 14 A preliminary study of two alternative sites for a pond 12
to be used for livestock water, irrigation, and recreation
Figure 15 Approximate geographic boundaries for NRCS 19
rainfall distributions
vi
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Figure 16 Time of concentration (T,) nomograph 20
Figure 17a Unit peak discharge (qu) for Type I storm distribution 23
Figure 17b Unit peak discharge (qu) for Type IA storm distribution 23
Figure 17c Unit peak discharge (q,,) for Type II storm distribution 23
Figure 17d Unit peak discharge (qu) for Type III storm distribution 23
Figure 18 Borrow material taken from within the reservoir
area creates an irregular pond configuration 25
Figure 19 The apparent size of the pond is influenced by
surrounding vegetation 26
Figure 20 Plan, profile, and cross section of a natural spillway
with vegetation 29
Figure 21 Excavated earth spillway 33
Figure 22 Drop-inlet pipe spillway with antiseep collar 36
Figure 23 Drop-inlet pipe spillways 37
Figure 24 Dam with hooded inlet pipe spillway 39
Figure 25 Pipe inlet spillways that have trash rack and
antivortex baffle 40
Figure 26 Water is piped through the dam's drainpipe to
a stockwater trough 44
Figure 27 A core trench is cut on the centerline of a dam 45
Figure 28 Dam side slopes are curved and shaped to blend
with surounding topography 46
Figure 29 Finished grading techniques 47
Figure 30 A tree well preserves vegetation 53
Figure 31 Irregular clearing around the pond helps create
a natural appearing edge 54
Figure 32 Feathering vegetation at the pond's edge makes
a natural transition with existing vegetation 54
vii
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Figure 33 The sod and topsoil in a pond construction area 56
can be stockpiled for later use
Figure 34 Geometric excavation graded to create more 58
natural configuration
Figure 35 Typical sections of an excavated pond 59
Figure 36 Correct disposal of waste material 60
Figure 37 Waste material and plantings separate the pond 61
from a major highway
Figure 38 Disking in chemical additive to seal a pond 62
Viii
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Issued June 1982
Revised November 1997
The United States Department of Agriculture (USDA) prohibits discrimina-
tion in its programs on the basis of race, color, national origin, sex, religion,
age, disability, political beliefs, and marital or familial status. (Not all
prohibited bases apply to all programs.) Persons with disabilities who
require alternate means for communication of program information
(Braille, large print, audiotape, etc.) should contact the USDA's TARGET
Center at [phone] (voice and TDD).
To file a complaint, write the Secretary of Agriculture, U.S. Department of
Agriculture, Washington, DC, 20250, or call 1-800-245-6340 or [phone]
(TDD). USDA is an equal opportunity employer.
Agriculture Handbook 590
Introduction
Ponds Planning, Design,
Construction
For many years farmers and ranchers have been
building ponds for livestock water and for irrigation.
By 1980 more than 2.1 million ponds had been built in
the United States by land users on privately owned
land. More will be needed in the future.
The demand for water has increased tremendously in
recent years, and ponds are one of the most reliable
and economical sources of water. Ponds are now
serving a variety of purposes, including water for
livestock and for irrigation, fish production, field and
orchard spraying, fire protection, energy conservation,
wildlife habitat, recreation, erosion control, and land-
scape improvement.
This handbook describes embankment and excavated
ponds and outlines the requirements for building each.
The information comes from the field experience and
observation of land users, engineers, conservationists,
and other specialists.
- Top of
settled fill
i
i
i
Auxiliary
spillway
i
Backslope
Figure 1 Typical embankment and reservoir
Cross section
(not to scale) Top of
constructed fill
Temporary pool
I Stage i--
Normal pool P.S. inlet
crest 7,
InTlet
? Barrel
Frontslope
Core trench
An embankment pond (fig. 1) is made by building an
embankment or dam across a stream or watercourse
where the stream valley is depressed enough to permit
storing 5 feet or more of water. The land slope may
range from gentle to steep.
An excavated pond is made by digging a pit or dugout
in a nearly level area. Because the water capacity is
obtained almost entirely by digging, excavated ponds
are used where only a small supply of water is needed.
Some ponds are built in gently to moderately sloping
areas and the capacity is obtained both by excavating
and by building a dam.
The criteria and recommendations are for dams that
are less than 35 feet high and located where failure of
the structure will not result in loss of life; in damage to
homes, commercial or industrial buildings, main
highways, or railroads; or in interrupted use of public
utilities.
Local information is essential, and land users are
encouraged to consult with specialists experienced in
planning and building ponds.
O
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channel
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Water needs
Livestock
Clean water and ample forage are equally essential for
livestock to be finished out in a marketable condition.
If stockwater provisions in pasture and range areas are
inadequate, grazing will be concentrated near the
water and other areas will be undergrazed. This can
contribute to serious livestock losses and instability in
the livestock industry.
Watering places must also be properly distributed in
relation to the available forage. Areas of abundant
forage may be underused if water is not accessible to
livestock grazing on any part of that area (fig. 2).
Providing enough watering places in pastures encour-
ages more uniform grazing, facilitates pasture im-
provement practices, retards erosion, and enables
farmers to make profitable use of soil-conserving
crops and erodible, steep areas unfit for cultivation.
An understanding of stockwater requirements helps in
planning a pond large enough to meet the needs of the
stock using the surrounding grazing area. The average
daily consumption of water by different kinds of
livestock shown here is a guide for estimating water
needs.
Kind of livestock
Beef cattle and horses
Dairy cows (drinking only)
Dairy cows (drinking and
barn needs)
Hogs
Sheep
Gallons per head per day
12 to 15
15
35
4
The amount of water consumed at one pond depends
on the average daily consumption per animal, number
of livestock served, and period over which they are
served.
Figure 2 This pond supplies water to a stockwater trough used by cattle in nearby grazing area
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Irrigation
Farm ponds are now an important source of irrigation
water (fig. 3), particularly in the East, which does not
have the organized irrigation enterprises of the West.
Before World War II irrigation was not considered
necessary in the humid East. Now many farmers in the
East are irrigating their crops.
Water requirements for irrigation are greater than
those for any other purpose discussed in this hand-
book. The area irrigated from a farm pond is limited by
the amount of water available throughout the growing
season. Pond capacity must be adequate to meet crop
requirements and to overcome unavoidable water
losses. For example, a 3-inch application of water on
1 acre requires 81,462 gallons. Consequently, irrigation
from farm ponds generally is limited to high-value
crops on small acreages, usually less than 50 acres.
The required storage capacity of a pond used for
irrigation depends on these interrelated factors: water
requirements of the crops to be irrigated, effective
rainfall expected during the growing season, applica-
tion efficiency of the irrigation method, losses due to
evaporation and seepage, and the expected inflow to
the pond. Your local NRCS conservationist can help
you estimate the required capacity of your irrigation pond.
Fish production
Many land users are finding that fish production is
profitable. A properly built and managed pond can
yield from 100 to 300 pounds of fish annually for each
acre of water surface. A good fish pond can also
provide recreation (fig. 4) and can be an added source
of income should you wish to open it to people in the
community for a fee.
Ponds that have a surface area of a quarter acre to
several acres can be managed for good fish produc-
tion. Ponds of less than 2 acres are popular because
they are less difficult to manage than larger ones. A
minimum depth of 8 feet over an area of approximately
1,000 square feet is needed for best management.
Figure 3 Water is pumped out of this pond for irrigation
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Field and orchard spraying
You may wish to provide water for applying pesticides
to your field and orchard crops. Generally, the amount
of water needed for spraying is small, but it must be
available when needed. About 100 gallons per acre for
each application is enough for most field crops. Or-
chards, however, may require 1,000 gallons or more
per acre for each spraying.
Provide a means of conveying water from the pond to
the spray tank. In an embankment pond, place a pipe
through the dam and a flexible hose at the down-
stream end to fill the spray tank by gravity. In an
excavated pond, a small pump is needed to fill the
tank.
Fire protection
A dependable water supply is needed for fighting fire.
If your pond is located close to your house, barn, or
other buildings, provide a centrifugal pump with a
power unit and a hose long enough to reach all sides
of all the buildings. Also provide for one or more dry
hydrants (figs. 5 and 6).
Although water-storage requirements for fire protec-
tion are not large, the withdrawal rate for fire fighting
is high. A satisfactory fire stream should be at least
250 gallons per minute with pressure at the nozzle of
at least 50 pounds per square inch. Fire nozzles gener-
ally are 1 inch to 1-1/2 inches in diameter. Use good
quality rubber-lined firehoses, 2-1/2 to 3 inches in
diameter. Preferably, the hose should be no more than
600 feet long.
A typical firehose line consists of 500 feet of 3-inch
hose and a 1-1/8 inch smooth nozzle. A centrifugal
pump operating at 63 pounds per square inch provides
a stream of 265 gallons per minute with a nozzle pres-
sure of 50 pounds per square inch. Such a stream
running for 5 hours requires 1/4 acre-foot of water. If
you live in an area protected by a rural fire fighting
organization, provide enough storage to operate sev-
eral such streams. One acre-foot of storage is enough
for four streams.
Your local dealer in pumps, engines, and similar equip-
ment can furnish the information you need about
pump size, capacity, and engine horsepower.
Figure 4 A pond stocked with fish can provide recreation as well as profit
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Figure 5 A dry hydrant is needed when a pond is close enough to a home or barn to furnish water for fire fighting
Figure 6 Details of a dry hydrant installation
4.5-in bronze
cap-steamer
hose
connection
Bronze nipple 4.5-in in steamer
to 4 or 6 in pipe
IIII 1111111
? 4- or 6-in pipe elbow
74 , 4- 4- or 6-in pipe riser
i/ ;p\?
de ?-- Ground line
I ! \'
Pumping lift not over 18 ft
Cast iron elbow
4- or 6-in galvanized steel or I Suction pipe
other equally durable pipe
Not to scale
Farm pond water level
Gravel covering
depth of 12 in
oVg? °"
1 `Up?aO00 80?
0
08 Z oso G
Well screen
5
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Recreation
A pond can provide many pleasant hours of swimming,
boating, and fishing. The surrounding area can be
made into an attractive place for picnics and games
(fig. 7).
Many land users realize additional income by provid-
ing water for public recreation. If the public is invited
to use a pond for a fee, the area must be large enough
to accommodate several parties engaged in whatever
recreation activities are provided.
If a pond is to be used for public recreation, supply
enough water to overcome evaporation and seepage
losses and to maintain a desirable water level. A pond
used for swimming must be free of pollution and have
an adequate depth of water near a gently sloping
shore. Minimum facilities for public use and safety are
also needed. These facilities include access roads,
parking areas, boat ramps or docks, fireplaces, picnic
tables, drinking water, and sanitary facilities.
To protect public health, most states have laws and
regulations that require water supplies to meet certain
prescribed standards if they are to be used for swim-
ming and human consumption. Generally, water must
be tested and approved before public use is permitted.
There are also rules and regulations for building and
maintaining public sanitary facilities. The state board
of health or a similar agency administers such laws
and regulations. Contact your local health agency to
become familiar with those regulations before making
extensive plans to provide water for public recreation.
Waterfowl and other wildlife
Ponds attract many kinds of wildlife. Migratory water-
fowl often use ponds as resting places in their flights
to and from the North. Ducks often use northern
ponds as breeding places, particularly where the food
supply is ample (fig. 8). Upland game birds use ponds
as watering places.
Landscape quality
Water adds variety to a landscape and further en-
hances its quality. Reflections in water attract the eye
and help to create a contrast or focal point in the
landscape (fig. 9). A pond visible from a home, patio,
or entrance road increases the attractiveness of the
landscape and often increases land value. Ponds in
rural, suburban, and urban areas help to conserve or
improve landscape quality.
Figure 7 Ponds are often used for private as well as public recreation
6
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Figure 8 Waterfowl use ponds as breeding, feeding, watering places, and as resting places during migration
t

MEL 14L.- It &J"r
P "'t

Figure 9 The shoreline of a well-designed pond is protected from erosion by the addition of stone.
Such a pond, reflecting nearby trees, increases the value of the surrounding land
7
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Regardless of its purpose, a pond's appearance can be
improved by using appropriate principles and tech-
niques of design. Good design includes consideration
of size, site visibility, relationship to the surrounding
landscape and use patterns, and shoreline configuration.
Your local NRCS conservationist can help you apply
the basic principles and design techniques. Consult a
landscape architect for additional information and
special designs.
Multiple purposes
You may wish to use the water in your pond for more
than one purpose; for example, to provide water for
livestock, fish production, and spraying field crops. If
so, two additional factors must be considered.
First, in estimating your water requirements you must
total the amounts needed for each purpose and be
sure that you provide a supply adequate for all the
intended uses.
Second, make sure that the purposes for which the
water is to be used are compatible. Some combina-
tions, such as irrigation and recreation, generally are
not compatible. You would probably use most of the
water during the irrigation season, making boating and
swimming impractical.
Ponds used temporarily for grade control or as sedi-
ment basins associated with construction sites can be
converted later into permanent ponds by cleaning out
the sediment, treating the shoreline, and adding land-
scape measures (fig. 10). If a sediment basin is to be
cleaned and reconstructed as a water element, the
standards for dam design should be used.
Figure 10 This pond, which served as a sediment basin while homes in the background were being constructed, now adds
variety and value to the community
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Preliminary investigations
General considerations
Selecting a suitable site for your pond is important,
and preliminary studies are needed before final design
and construction. Analysis and selection of pond sites
should be based on landscape structure and associ-
ated ecological functions and values. Relationship of
the site to other ecological features within the land-
scape is critical to achieving planned objectives. If
possible, consider more than one location and study
each one to select the most ecologically appropriate,
esthetic, and practical site. Weighing both onsite and
offsite effects of constructing a pond is essential in
site selection. Refer to figure 1 and the glossary to
become familiar with the components of a pond and
associated dam.
For economy, locate the pond where the largest stor-
age volume can be obtained with the least amount of
earthfill. A good site generally is one where a dam can
be built across a narrow section of a valley, the side
slopes are steep, and the slope of the valley floor
permits a large area to be flooded. Such sites also
minimize the area of shallow water. Avoid large areas
of shallow water because of excessive evaporation
and the growth of noxious aquatic plants.
If farm ponds are used for watering livestock, make a
pond available in or near each pasture or grazing unit.
Forcing livestock to travel long distances to water is
detrimental to both the livestock and the grazing area.
Space watering places so that livestock does not travel
more than a quarter mile to reach a pond in rough,
broken country or more than a mile in smooth, nearly
level areas. Well-spaced watering places encourage
uniform grazing and facilitate grassland management.
If pond water must be conveyed for use elsewhere,
such as for irrigation or fire protection, locate the
pond as close to the major water use as practicable.
Conveying water is expensive and, if distance is exces-
sive, the intended use of the water may not be practical.
Ponds for fishing, boating, swimming, or other forms
of recreation must be reached easily by automobile,
especially if the general public is charged a fee to use
the pond. The success of an income-producing recre-
ation enterprise often depends on accessibility.
Avoid pollution of pond water by selecting a location
where drainage from farmsteads, feedlots, corrals,
sewage lines, mine dumps, and similar areas does not
reach the pond. Use permanent or temporary mea-
sures, such as diversions, to redirect runoff from these
sources to an appropriate outlet until the areas can be
treated.
Do not overlook the possibility of failure of the dam
and the resulting damage from sudden release of
water. Do not locate your pond where failure of the
dam could cause loss of life; injury to persons or
livestock; damage to homes, industrial buildings,
railroads, or highways; or interrupted use of public
utilities. If the only suitable pond site presents one or
more of these hazards, hire a qualified person to
investigate other potential sites to reduce the possibil-
ity of failure from improper design or construction.
Be sure that no buried pipelines or cables cross a
proposed pond site. They could be broken or punc-
tured by the excavating equipment, which can result
not only in damage to the utility, but also in injury to
the operator of the equipment. If a site crossed by
pipelines or cable must be used, you must notify the
utility company before starting construction and
obtain permission to excavate.
Avoid sites under powerlines. The wires may be within
reach of a fishing rod held by someone fishing from
the top of the dam.
Area adequacy of the drainage
For ponds where surface runoff is the main source of
water, the contributing drainage area must be large
enough to maintain water in the pond during droughts.
However, the drainage area should not be so large that
expensive overflow structures are needed to bypass
excess runoff during large storms.
The amount of runoff that can be expected annually
from a given watershed depends on so many interre-
lated factors that no set rule can be given for its deter-
mination. The physical characteristics that directly
affect the yield of water are relief, soil infiltration,
plant cover, and surface storage. Storm characteris-
Agriculture Handbook 590
Ponds-Planning, Design, Construction
tics, such as amount, intensity, and duration of rainfall,
also affect water yield. These characteristics vary
widely throughout the United States. Each must be
considered when evaluating the watershed area condi-
tions for a particular pond site.
Figure 11 is a general guide for estimating the approxi-
mate size of drainage area needed for a desired water-
storage capacity. For example, a pond located in west-
central Kansas with a capacity of 5 acre-feet requires a
drainage area of at least 175 acres under normal condi-
tions. If reliable local runoff information is available,
use it in preference to the guide.
Average physical conditions in the area are assumed to
be the normal runoff-producing characteristics for a
drainage area, such as moderate slopes, normal soil
infiltration, fair to good plant cover, and normal sur-
face storage.
To apply the information given in figure 11, some
adjustments may be necessary to meet local condi-
tions. Modify the values in the figure for drainage
areas having characteristics other than normal. Re-
duce the values by as much as 25 percent for drainage
areas having extreme runoff-producing characteristics.
Increase them by 50 percent or more for low runoff-
producing characteristics.
Minimum pond depth
To ensure a permanent water supply, the water must
be deep enough to meet the intended use requirements
and to offset probable seepage and evaporation losses.
These vary in different sections of the country and
from year to year in any one section. Figure 12 shows
the recommended minimum depth of water for ponds
if seepage and evaporation losses are normal. Deeper
ponds are needed where a permanent or year-round
water supply is essential or where seepage losses
exceed 3 inches per month.
Figure 11 A guide for estimating the approximate size of a drainage area (in acres) required for each acre-foot of storage in
an embankment or excavated pond
10
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Drainage area protection
To maintain the required depth and capacity of a pond,
the inflow must be reasonably free of silt from an
eroding watershed. The best protection is adequate
application and maintenance of erosion control prac-
tices on the contributing drainage area. Land under
permanent cover of trees, grass, or forbs is the most
desirable drainage area (fig. 13). Cultivated areas
protected by conservation practices, such as terraces,
conservation tillage, stripcropping, or conservation
cropping systems, are the next best watershed conditions.
If an eroding or inadequately protected watershed
must be used to supply pond water, delay pond con-
struction until conservation practices are established.
In any event, protection of the drainage area should be
started as soon as you decide to build a pond.
Figure 13 Land with permanent vegetation makes the
most desirable drainage area
Figure 12 Recommended minimum depth of water for ponds in the United States
Wei
Humic
Moist subhumic
Dry Subhumic
Semiaric
Arid " 12-14 foot pond depth
II
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Pond capacity Landscape evaluation
Estimate pond capacity to be sure that enough water
is stored in the pond to satisfy the intended use re-
quirements. A simple method follows:
• Establish the normal pond-full water elevation
and stake the waterline at this elevation.
• Measure the width of the valley at this elevation
at regular intervals and use these measurements
to compute the pond-full surface area in acres.
• Multiply the surface area by 0.4 times the maxi-
mum water depth in feet measured at the dam.
For example, a pond with a surface area of 3.2 acres
and a depth of 12.5 feet at the dam has an approximate
capacity of 16 acre-feet (0.4 x 3.2 x 12.5 = 16 acre-feet)
[1 acre-foot = 325,651 gallons].
Alternative pond sites should be evaluated for poten-
tial visibility and compatibility with surrounding
landscape characteristics and use patterns (fig. 14).
Identify major viewpoints (points from which the site
is viewed) and draw the important sight lines with
cross sections, where needed, to determine visibility.
If feasible, locate the pond so that the major sight line
crosses the longest dimension of water surface. The
pond should be placed so that a viewer will see the
water first before noticing the dam, pipe inlet, or
spillway. Often, minor changes in the dam alignment
and spillway location can shift these elements out of
view and reduce their prominence.
If possible, locate your pond so that some existing
trees and shrubs remain along part of the shoreline.
Vegetation adds aesthetic value by casting reflections
on the water, provides shade on summer days, and
helps blend the pond into the surrounding landscape.
A pond can often be located and designed so that an
island is created for recreation, wildlife habitat, or
visual interest.
In addition to the more typical farm and residential
sites, ponds can be located on poor quality landscapes
to rehabilitate abandoned road borrow areas, dumping
sites, abandoned rural mines, and other low produc-
tion areas.
Figure 14 A preliminary study of two alternative sites for a pond to be used for livestock water, irrigation, and recreation
--------------------------------------------- ------------
,s
Vegetable garden
Viewpoints 1 -III-I?III-
---- Sight lines ?
't-??? House s?
* I El
I 0
? Barn
Pond A
S
tockwater trough
.yam v '
k.i PondB
12
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Runoff curve numbers
Estimating storm runoff
The amount of precipitation, whether it occurs as rain
or snow, is the potential source of water that may run
off small watersheds. The kind of soil and the type of
vegetation affect the amount of water that runs off.
Terraces and diversions, along with steepness and
shape of a watershed, affect the rate at which water
runs off.
A spillway is provided to bypass surface runoff after
the pond is filled. The tables and charts in the follow-
ing sections should be used to estimate the peak
discharge rates for the spillway. They provide a quick
and reliable estimate of runoff rates and associated
volumes for a range of storm rainfall amounts, soil
groups, land use, cover conditions, and watershed
slopes.
Tables 1 through 4 show numerical runoff ratings for a
range of soil-use-cover complexes. Because these
numbers relate to a set of curves developed from the
NRCS runoff equation, they are referred to as curve
numbers (CN) in these tables.
The watershed upstream from a farm pond often
contains areas represented by different curve num-
bers. A weighted curve number can be obtained based
on the percentage of area for each curve number. For
example, assume that the watershed above a pond is
mainly (three-fourths) in good pasture and a soil in
hydrologic group B. The remainder is cultivated with
conservation treatment on a soil in hydrologic group C.
A weighted curve number for the total watershed
would be:
3/4 x 61 = 46 (approximately)
1/4 x 76 = 20 (approximately)
Weighted = 66
Hydrologic groupings of soils
Soils are classified in four hydrologic groups accord-
ing to infiltration and transmission rates:
A-These soils have a high infiltration rate. They are
chiefly deep, well-drained sand or gravel. The runoff
potential is low.
B-These soils have a moderate infiltration rate when
thoroughly wet. They are chiefly moderately deep,
well-drained soils of moderately fine to moderately
coarse texture.
C-These soils have a slow infiltration rate when wet.
These moderately fine to fine texture soils have a layer
that impedes downward movement of water.
D-These soils have a very slow infiltration rate. They
are chiefly clay soils that have a high swelling poten-
tial, soils with a permanent high water table, soils with
a claypan at or near the surface, and shallow soils over
nearly impervious material. The runoff potential is high.
The NRCS district conservationist or your county
extension agent can help you classify the soils for a
given pond site in one of the four hydrologic groups.
13
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Table 1 Runoff curve numbers for urban areas 1/
Cover description Average percent Curve numbers for hydrologic soil group
impervious area ?/ A B C D
Fully developed urban areas
(vegetation established)
Open space (lawns, parks, golf courses, cemeteries, etc.) 3/
Poor condition (grass cover < 50%) 68 79 86 89
Fair condition (grass cover 50 to 75%) 49 69 79 84
Good condition (grass cover > 75%) 39 61 74 80
Impervious areas:
Paved parking lots, roofs, driveways, etc. 98 98 98 98
(excluding right-of-way)
Streets and roads:
Paved; curbs and storm sewers (excluding right-of-way) 98 98 98 98
Paved; open ditches (including right-of-way) 83 89 92 93
Gravel (including right-of-way) 76 85 89 91
Dirt (including right-of-way) 72 82 87 89
Western desert urban areas:
Natural desert landscaping (pervious areas only) 4/ 63 77 85 88
Artificial desert landscaping (impervious weed barrier,
desert shrub with 1- to 2-inch sand or gravel mulch and 96 96 96 96
basin borders)
Urban districts:
Commercial and business 85 89 92 94 95
Industrial 72 81 88 91 93
Residential districts by average lot size:
1/8 acre or less (town houses) 65 77 85 90 92
1/4 acre 38 61 75 83 87
1/3 acre 30 57 72 81 86
1/2 acre 25 54 70 80 85
1 acre 20 51 68 79 84
2 acres 12 46 65 77 82
Developing urban areas
Newly graded areas (pervious areas only, no vegetation) 5J 77 86 91 94
Idle lands (CN's are determined using cover types similar to those in table 3)
l/ Average runoff condition, and Ia = 0.2S.
2/ The average percent impervious area shown was used to develop the composite CN's. Other assumptions are as follows: impervious areas
are directly connected to the drainage system, impervious areas have a CN of 98, and pervious areas are considered equivalent to open
space in good hydrologic condition. CN's for other combinations of conditions may be computed using figure 2-3 or 2-4 in NRCS Technical
Release 55, Urban Hydrology for Small Watersheds.
3/ CN's shown are equivalent to those of pasture. Composite CN's may be computed for other combinations of open space cover type.
4/ Composite CN's for natural desert landscaping should be computed using figure 2-3 or 2-4 in Technical Release 55, based on the impervious area
percentage (CN = 98) and the pervious area CN. The pervious area CN's are assumed equivalent to desert shrub in poor hydrologic condition.
5/ Composite CN's to use for the design of temporary measures during grading and construction should be computed using figure 2-3 or 2-4 in
Technical Release 55, based on the degree of development (impervious area percentage) and the CN's for the newly graded pervious areas.
14
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Table 2 Runoff curve numbers for agricultural lands i/
Cover description Curve numbers for hydrologic soil group
Cover type Treatment ?/ Hydrologic condition 2/ A B C D
Fallow Bare soil - 77 86 91 94
Crop residue cover (CR) Poor 76 85 90 93
Good 74 83 88 90
Row crops Straight row (SR) Poor 72 81 88 91
Good 67 78 85 89
SR + CR Poor 71 80 87 90
Good 64 75 82 85
Contoured (C) Poor 70 79 84 88
Good 65 75 82 86
C + CR Poor 69 78 83 87
Good 64 74 81 85
Contoured & terraced (C&T) Poor 66 74 80 82
Good 62 71 78 81
C&T + CR Poor 65 73 79 81
Good 61 70 77 80
Small grain SR Poor 65 76 84 88
Good 63 75 83 87
SR + CR Poor 64 75 83 86
Good 60 72 80 84
C Poor 63 74 82 85
Good 61 73 81 84
C + CR Poor 62 73 81 84
Good 60 72 80 83
C&T Poor 61 72 79 82
Good 59 70 78 81
C&T + CR Poor 60 71 78 81
Good 58 69 77 80
Closed-seeded SR Poor 66 77 85 89
or broadcast Good 58 72 81 85
legumes or C Poor 64 75 83 85
rotation Good 55 69 78 83
meadow C&T Poor 63 73 80 83
Good 51 67 76 80
l/ Average runoff condition, and Ia = 0.2S.
2/ Crop residue cover applies only if residue is on at least 5 percent of the surface throughout the year.
3/ Hydrologic condition is based on combination of factors that affect infiltration and runoff, including (a) density and canopy of vegetative
areas, (b) amount of year-round cover, (c) amount of grass or close-seeded legumes in rotations , (d) percentage of residue cover on the land
surface (good > 20%), and (e) degree of surface roughness.
Poor: Factors impair infiltration and tend to increase runoff.
Good: Factors encourage average and better than average infiltration and tend to decrease run off.
15
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Table 3 Runoff curve numbers for other agricultural lands 1/
Cover description Curve numbers for hydrologic soil group
Cover type Hydrologic condition I/ A B C D
Pasture, grassland, or range-continuous grazing ?/
Meadow-continuous grass, protected from
grazing and generally mowed for hay
Brush-brush-weed-grass mixture with brush
the major element 3/
Woods-grass combination (orchard
or tree farm) 5/
Woods 6/
Farmsteads-buildings, lanes, driveways,
and surrounding lots.
Poor 68 79 86 89
Fair 49 69 79 84
Good 39 61 74 80
- 30 58 71 78
Poor 48 67 77 83
Fair 35 56 70 77
Good 30 4/ 48 65 73
Poor 57 73 82 86
Fair 43 65 76 82
Good 32 58 72 79
Poor 45 66 77 83
Fair 36 60 73 79
Good 30 4/ 55 70 77
- 59 74 82 86
l/ Average runoff condition, and Ia = 0.2S.
2/ Poor: <50% ground cover or heavily grazed with no mulch.
Fair: 50 to 75% ground cover and not heavily grazed.
Good: >75% ground cover and lightly or only occasionally grazed.
3/ Poor: <50% ground cover.
Fair: 50 to 75% ground cover.
Good: >75% ground cover.
4/ Actual curve number is less than 30: use CN = 30 for runoff computations.
5/ CN's shown were computed for areas with 50% woods and 505 grass (pasture) cover. Other combinations of conditions may be computed
from the CN's for woods and pasture.
6/ Poor: Forest litter, small trees, and brush are destroyed by heavy grazing or regular burning.
Fair: Woods are grazed but not burned, and some forest litter covers the soil.
Good: Woods are protected from grazing, and litter and brush adequately cover the soil.
16
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Table 4 Runoff curve numbers for and and semiarid rangelands 1/
Cover description Curve numbers for hydrologic soil group
Cover type Hydrologic condition 2/ A N B C D
Herbaceous-mixture of grass, forbs, and Poor - 80 87 93
low-growing brush, with brush the minor element Fair - 71 81 89
Good - 62 74 85
Oak-aspen-mountain brush mixture of oak brush, Poor - 66 74 79
aspen, mountain mahogany, bitter brush, maple, Fair - 48 57 63
and other brush. Good - 30 41 48
Pinyon-juniper-pinyon, juniper, or both Poor - 75 85 89
grass understory Fair - 58 73 80
Good - 41 61 71
Sagebrush with grass understory Poor - 67 80 85
Fair - 51 63 70
Good - 35 47 55
Desert shrub-major plants include saltbush, Poor 63 77 85 88
greasewood, creosotebush, blackbrush, bursage, Fair 55 72 81 86
palo verde, mesquite, and cactus Good 49 68 79 84
1/ Average runoff condition, and Ia = 02S. For range in humid regions, use table 3.
2/ Poor: <30% ground cover (litter, grass, and brush overstory).
Fair: 30 to 70% ground cover.
Good: >70% ground cover.
3/ Curve numbers for group A have been developed only for desert shrub.
17
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Volume of storm runoff
Often knowing how much water runs off from a big
storm as well as the rate at which it flows is good. The
volume is needed to compute needed storage as well
as the peak discharge rate.
The figures in table 5 are the depth (in inches) at
which the storm runoff, if spread evenly, would cover
the entire watershed. For example, the volume of
runoff from a 3-inch rainfall on a 100-acre watershed
with the weighted curve number of 66 would be:
0.55 inch (interpolated between 0.51 and 0.72 inches)
100 acres x 0.55 inch = 55 acre-inches
55 acre-inches =12 = 4.55 acre-feet
55 acre-inches x 27,152 gallons per acre-inch = 1.5
million gallons (approximately)
Table 5 Runoff depth, in inches
Rainfall Curve number
(inches) 60 65 70 75 80 85 90
1.0 0 0 0 0.03 0.08 0.17 0.32
1.2 0 0 0.03 0.07 0.15 0.28 0.46
1.4 0 0.02 0.06 0.13 0.24 0.39 0.61
1.6 0.01 0.05 0.11 0.20 0.34 0.52 0.76
1.8 0.03 0.09 0.17 0.29 0.44 0.65 0.93
2.0 0.06 0.14 0.24 0.38 0.56 0.80 1.09
2.5 0.17 0.30 0.46 0.65 0.89 1.18 1.53
3.0 0.33 0.51 0.72 0.96 1.25 1.59 1.98
4.0 0.76 1.03 1.33 1.67 2.04 2.46 2.92
5.0 1.30 1.65 2.04 2.45 2.89 3.37 3.88
6.0 1.92 2.35 2.87 3.28 3.78 4.31 4.85
7.0 2.60 3.10 3.62 4.15 4.69 5.26 5.82
8.0 3.33 3.90 4.47 5.04 5.62 6.22 6.81
9.0 4.10 4.72 5.34 5.95 6.57 7.19 7.79
10.0 4.90 5.57 6.23 6.88 7.52 8.16 8.78
11.0 5.72 6.44 7.13 7.82 8.48 9.14 9.77
12.0 6.56 7.32 8.05 8.76 9.45 10.12 10.76
18
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Rainfall amounts and expected
frequency
Maps in U.S. Weather Bureau Technical Paper 40
(USWP-TP-40), Rainfall Frequency Atlas of the United
States, show the amount of rainfall expected in a 24-
hour period. These maps have also been reprinted in
Hydrology for Small Urban Watershed, Technical
Release 55. Contact your local NRCS field office for
rainfall amounts on maps.
Designing an ordinary pond spillway to accommodate
the peak rate of runoff from the most intense rain-
storm ever known or anticipated is not practical. The
spillway for an ordinary farm pond generally is de-
signed to pass the runoff from a 25-year frequency
storm. This means a storm with only a 4 percent
chance of occurring in any year or the size beyond
which larger storms would not occur more often than
an average of once in 25 years. Designing for a 50-year
storm frequency is recommended for spillways for
larger dams. A 10-year storm frequency may be ad-
equate for sizing the spillway in small ponds.
Rainfall distribution
The highest peak discharges from small watersheds
are usually caused by intense, brief rainfalls that may
occur as part of a longer duration storm. Different
rainfall distributions with respect to time have been
developed for four geographic areas of the United
States. For each of these areas, a set of synthetic
rainfall distributions having nested rainfall intensities
were developed. These distributions maximize the
rainfall intensities by incorporating selected storm
duration intensities within those needed for longer
durations at the same probability level.
In figure 15, type I and IA represent the Pacific mari-
time climate with wet winters and dry summers. Type
III represents Gulf of Mexico and Atlantic coastal
areas where tropical storms bring large rainfall
amounts. Type II represents the rest of the country.
Figure 15 Approximate geographic boundaries for NRCS rainfall distributions
j
A

Z00 <W 6WMi
19
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Peak discharge rate
The slope of the land above the pond affects the peak
discharge rate significantly. The time of concentration
along with the runoff curve number, storm rainfall,
and rainfall distribution are used to estimate the peak
discharge rate. This rate is used to design the auxiliary
spillway width and depth of flow.
Time of concentration
Time of concentration (Tc) is the time it takes for
runoff to travel from the hydraulically most distant
point of the watershed to the outlet. Tc influences the
peak discharge and is a measure of how fast the water
runs off the land. For the same size watershed, the
shorter the Tc, the larger the peak discharge. This
means that the peak discharge has an inverse relation-
ship with Tc. Tc can be estimated for small rural water-
sheds using equation 1. Figure 16 is a nomograph for
solving this equation.
1°a (1000)-9 7
T` CN [Eq. 1
1140 Yo.s
where:
Tc = time of concentration, hr
I = flow length, ft
CN = runoff curve number
Y = average watershed slope, %
Figure 16 Time of concentration (Td nomograph
Flow length (1), feet
100 1,000 10,000
0.1 .3 .5 1.0 2 3 4 56 810
Time of concentration (T,), hrs
20
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Average watershed slope Table 6 la values for ru noff curve numbers
The average watershed slope (Y) is the slope of the
land and not the watercourse. It can be determined
Curve
la
Curve
la
from soil survey data or topographic maps. Hillside number (in) number (in)
slopes can be measured with a hand level, lock level,
or clinometer in the direction of overland flow. Aver- 40 3.000 70 0.857
age watershed slope is an average of individual land 41 2.878 71 0.817
slope measurements. The average watershed slope can 42 2.762 72 0.778
be determined using equation 2: 43 2.651 73 0.740
44 2.545 74 0.703
MCI
Y=
[Eq.21 45 2.444 75 0.667
A 46 2.348 76 0.632
where: 47 2.255 77 0.597
Y = average slope, % 48 2.167 78 0.564
C = total contour length, ft 49 2.082 79 0.532
I =contour interval, ft 50 2.000 80 0.500
A = drainage area, ft2 51 1.922 81 0.469
52 1.846 82 0.439
53 1.774 83 0.410
Flow length 54 1.704 84 0.381
55 1.636 85 0.353
Flow length (b is the longest flow path in the water- 56 1.571 86 0.326
shed from the watershed divide to the outlet. It is the 57 1.509 87 0.299
total path water travels overland and in small channels 58 1.448 88 0.273
on the way to the outlet. The flow length can be deter- 59 1.390 89 0.247
mined using a map wheel, or it can be marked along 60 1.333 90 0.222
the edge of a paper and converted to feet. 61 1.279 91 0.198
62 1.226 92 0.174
63 1.175 93 0.151
Ia /P ratio 64 1.125 94 0.128
65 1.077 95 0.105
The watershed CN is used to determine the initial 66 1.030 96 0.083
abstraction (Ij from table 6. Idl? ratio is a parameter 67 0.985 97 0.062
that indicates how much of the total rainfall is needed 68 0.941 98 0.041
to satisfy the initial abstraction. The larger the Ia/P ratio, 69 0.899
the lower the unit peak discharge (q„) for a given T,
21
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Estimating peak discharge rates
The unit peak discharge (qa) is obtained from figure 17
depending on the rainfall type. Figure 15 shows the
approximate geographic boundaries for the four
rainfall distributions. Tcand Ia/P values are needed to
obtain a value for q„ from the exhibit. The peak dis-
charge (qp in ft3/s) is computed as the product of the
unit peak discharge (qu in ft3/s/ac-in), the drainage
area (A in acres), and the runoff (Q in inches).
qp = q, ,x Ax Q [Eq. 3]
Example 1 Estimating peak discharge rates
Known:
Drainage area = 50 acres
Cole County, Missouri
Flow Path `1' = 1,600 feet
Watershed Slope `Y' = 4 percent
25-year, 24-hour rainfall = 6 inches
Type II rainfall distribution
Runoff Curve Number = 66
(from example in runoff curve number section)
Solution:
Find T,
Enter figure 16, Tc = 0.60 hours
Find la /P
Enter table 6, use CN = 66, la = 1.030
Ia lP = 1.030/6.0 inches = 0.172
Find runoff
Enter table 5, at rainfall = 6.0 inches
and runoff curve number = 66,
Read runoff = 2.44 inches. (Note: It was neces-
sary to interpolate between RCN 65 and 70.)
Find the peak discharge for spillway design.
Enter figure 17(c):
qu = 0.7
qp=quxAxQ
qp=0.7x50x2.44=85ft3/s
22
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Figure 17a Unit peak discharge (qu) for Type I storm Figure 17c Unit peak discharge (qu) for Type II storm
distribution distribution
.8
.7
.6
•U
° .5
y
w .4
0
a .3
v
.2
v
b
x
o. .1
G .08
.07
.06
.1 .2 .3 .4 .5 .6 .8 1.0 5 10
Time of concentration (T,), hours
Figure 17b Unit peak discharge (qu) for Type IA storm
distribution
.3
c
U
H
2
w
0
c
ao
4
CO
x
ai .1
fl .09
x
M .08
01.07
?.06F
05 L
.1
1
Time of concentration (Tc), hours
10
1.6
c
m 1.0
h
.6
c' .5
4
ao
.3
U
H
x
m
m
a
.1
D
.07 l 1 1 I I I I I
1 1.0 10
Time of concentration (T.), hours
Figure 17d Unit peak discharge (qu) for Type III storm
distribution
1.6
a
1.0
N
M 7
.6
c .5
.4
en
.3
x
m
a
.1
07
.1 1.0 10
Time of concentration (T,), hours
23
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Site surveys
Once you determine the probable location of the pond,
conduct a site survey to plan and design the dam,
spillways, and other features. Those unfamiliar with
the use of surveying instruments should employ a
licensed surveyor or other qualified professional.
Pond surveys generally consist of a profile of the
centerline of the dam, a profile of the centerline of the
earth spillway, and enough measurements to estimate
pond capacity. A simple method of estimating pond
capacity is described on page 12. For larger and more
complex ponds, particularly those used for water
supply or irrigation, you may need a complete topo-
graphic survey of the entire pond site.
Run a line of profile level surveys along the centerline
of the proposed dam and up both sides of the valley
well above the expected elevation of the top of the
dam and well beyond the probable location of the
auxiliary spillway. The profile should show the surface
elevation at all significant changes in slope and at
intervals of no more than 100 feet. This line of levels
establishes the height of the dam and the location and
elevation of the earth spillway and the principal spill-
way. It is also used to compute the volume of earthfill
needed to build the dam.
Run a similar line of profile levels along the centerline
of the auxiliary spillway. Start from a point on the
upstream end that is well below the selected normal
water surface elevation and continue to a point on the
downstream end where water can be safely discharged
without damage to the dam. This line serves as a basis
for determining the slope and dimensions of the spill-
way.
All surveys made at a pond site should be tied to a
reference called a bench mark. This may be a large
spike driven into a tree, an iron rod driven flush with
the ground, a point on the concrete headwall of a
culvert, or any object that will remain undisturbed
during and after construction of the dam.
Embankment ponds
Detailed soils investigation
Soils in the ponded area-Suitability of a pond site
depends on the ability of the soils in the reservoir area
to hold water. The soil should contain a layer of mate-
rial that is impervious and thick enough to prevent
excessive seepage. Clays and silty clays are excellent
for this purpose; sandy and gravelly clays are usually
satisfactory. Generally, soils with at least 20 percent
passing the No. 200 sieve, a Plasticity Index of more
than 10 percent, and an undisturbed thickness of at
least 3 feet do not have excessive seepage when the
water depth is less than 10 feet. Coarse-textured sands
and sand-gravel mixtures are highly pervious and
therefore usually unsuitable. The absence of a layer of
impervious material over part of the ponded area does
not necessarily mean that you must abandon the
proposed site. You can treat these parts of the area by
one of several methods described later in this hand-
book. Any of these methods can be expensive.
Some limestone areas are especially hazardous as
pond sites. Crevices, sinks, or channels that are not
visible from the surface may be in the limestone below
the soil mantle. They may empty the pond in a short
time. In addition, many soils in these areas are granu-
lar. Because the granules do not break down readily in
water, the soils remain highly permeable. All the
factors that may make a limestone site undesirable are
not easily recognized without extensive investigations
and laboratory tests. The best clue to the suitability of
a site in one of these areas is the degree of success
others have had with farm ponds in the immediate
vicinity.
Unless you know that the soils are sufficiently impervi-
ous and that leakage will not be a problem, you should
make soil borings at intervals over the area to be
covered with water. Three or four borings per acre
may be enough if the soils are uniform. More may be
required if there are significant differences.
Foundation conditions-The foundation under a
dam must ensure stable support for the structure and
provide the necessary resistance to the passage of
water.
24
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Soil borings help to investigate thoroughly the founda-
tion conditions under the proposed dam site. The
depth of the holes should be at least 1-1/2 times the
height of the proposed dam. Ensure there are not any
steep dropoffs in the rock surface of the foundation
under the dam. Steep dropoffs in the rock surface can
result in cracking of the embankment. Study the
natural banks (abutments) at the ends of the dam as
well as the supporting materials under the dam. If the
dam is to be placed on rock, the rock must be exam-
ined for thickness and for fissures and seams through
which water might pass.
Coarse-textured materials, such as gravel, sand, and
gravel-sand mixtures, provide good support for a dam,
but are highly pervious and do not hold water. Such
materials can be used only if they are sealed to prevent
seepage under the dam. You can install a cutoff core
trench of impervious material under the dam or blan-
ket the upstream face of the dam and the pond area
with a leak-resistant material.
Fine-textured materials, such as silts and clays, are
relatively impervious, but have a low degree of stabil-
ity. They are not good foundation materials, but gener-
ally are satisfactory for the size of dams discussed in
this handbook. Flattening the side slopes of some
dams may be necessary to reduce the unit load on the
foundation. Remove peat, muck, and any soil that has
a high organic-matter content from the foundation.
Good foundation materials, those that provide both
stability and imperviousness, are a mixture of coarse-
and fine-textured soils. Some examples are gravel-
sand-clay mixtures, gravel-sand-silt mixtures, sand-
clay mixtures, and sand-silt mixtures.
Less desirable but still acceptable foundation materi-
als for ordinary pond dams are gravelly clays, sandy
clays, silty clays, silty and clayey fine sands, and
clayey silts that have slight plasticity.
Fill material-The availability of suitable material for
building a dam is a determining factor in selecting a
pond site. Enough suitable material should be located
close to the site so that placement costs are not exces-
sive. If fill material can be taken from the reservoir
area, the surrounding landscape will be left undis-
turbed and borrow areas will not be visible after the
pond has been filled (fig. 18).
Materials selected must have enough strength for the
dam to remain stable and be tight enough, when prop-
erly compacted, to prevent excessive or harmful
percolation of water through the dam. Soils described
as acceptable for foundation material generally are
acceptable for fill material. The exceptions are organic
silts and clays.
The best material for an earthfill contains particles
ranging from small gravel or coarse sand to fine sand
and clay in the desired proportions. This material
should contain about 20 percent, by weight, clay
particles. Though satisfactory earthfills can be built
from soils that vary from the ideal, the greater the
variance, the more precautions needed.
Soils containing a high percentage of gravel or coarse
sand are pervious and can allow rapid seepage
through the dam. When using these soils, place a core
of clay material in the center of the fill and flatten the
side slopes to keep the line of seepage from emerging
on the downstream slope.
Fill material that has a high clay content swells when
wet and shrinks when dry. The shrinkage may open
dangerous cracks. If these soils are dispersive, they
represent a serious hazard to the safety of the embank-
ment and should be avoided. Dispersive soils can be
identified by how easily they go into suspension in
water, by the presence of a gelatinous cloud around a
clod of soil in distilled water, and by the indefinite
Figure 18 Borrow material taken from within the
reservoir area creates an irregular pond
configuration
25
Agriculture Handbook 590
Ponds-Planning, Design, Construction
length of time they stay in suspension in still water.
High sodium soils identified in the soil survey for the
planned area of the embankment also indicate disper-
sive soils. If any of these indicators are found at the
proposed site, an engineer should be hired to provide
the necessary guidance for sampling, testing, and
using these soils for fill. For soils consisting mostly of
silt, such as the loess areas of western Iowa and along
the Mississippi River in Arkansas, Mississippi, and
Tennessee, the right degree of moisture must be main-
tained during construction for thorough compaction.
To estimate the proportion of sand, silt, and clay in a
sample of fill material, first obtain a large bottle with
straight sides. Take a representative sample of the fill
material and remove any gravel by passing the mate-
rial through a 1/4-inch sieve or screen. Fill the bottle to
about one-third with the sample material and finish
filling with water. Shake the bottle vigorously for
several minutes and then allow the soil material to
settle for about 24 hours. The coarse material (sand)
settles to the bottom first, and finer material (clay)
settles last. Estimate the proportion of sand, silt, and
clay by measuring the thickness of the different layers
with a ruler.
Landscape planning-The pond should be located
and designed to blend with the existing landform,
vegetation, water, and structures with minimum dis-
turbance. Landforms can often form the impoundment
with minimum excavation. Openings in the vegetation
can be used to avoid costly clearing and grubbing.
Existing structures, such as stone walls and trails, can
be retained to control pedestrian and vehicular traffic
and minimize disruption of existing use. In the area
where land and water meet, vegetation and landform
can provide interesting reflections on the water's
surface, guide attention to or from the water, frame
the water to emphasize it, and direct passage around
the pond.
A pond's apparent size is not always the same as its
actual size. For example, the more sky reflected on the
water surface, the larger a pond appears. A pond
surrounded by trees will appear smaller than a pond
the same size without trees or with some shoreline
trees (fig. 19). The shape of a pond should comple-
ment its surroundings. Irregular shapes with smooth,
flowing shorelines generally are more compatible with
the patterns and functions found in most landscapes.
Peninsulas, inlets, or islands can be constructed to
create diversity in the water's edge.
Spillway requirements
A pipe spillway often is used as well as an earth auxil-
iary spillway to control runoff from the watershed.
The principal spillway is designed to reduce the fre-
quency of operation of the auxiliary spillway. Com-
monly the principal spillway may be a hooded or
canopy inlet with a straight pipe or may be a drop inlet
(vertical section) that has a pipe barrel through the
dam. The pipe shall be capable of withstanding exter-
nal loading with yielding, buckling, or cracking. The
pipe joints and all appurtenances need to be water-
tight. Pipe materials may be smooth metal, corrugated
metal, or plastic. Design limitations exist with all
materials.
A small principal spillway pipe, formerly called a
trickle tube, only handles a small amount of flow. Its
purpose is to aid in keeping the auxiliary spillway dry
during the passage of small storm events.
Hooded or canopy inlets are common. A disadvantage
of this type inlet is the larger amount of stage (head
over the inlet crest) needed to make the pipe flow at
full capacity. Conversely, a drop inlet spillway requires
less stage because the size of the inlet may be enlarged
to make the barrel flow full.
Figure 19 The apparent size of the pond is influenced
by surrounding vegetation
26
Agriculture Handbook 590
Ponds-Planning, Design, Construction
The principal spillway normally is sized to control the
runoff from a storm ranging from a 1-year to a 10-year
frequency event. This depends on the size of the drain-
age area. For pond sites where the drainage area is
small (less than 20 acres) and the condition of the
vegetated spillway is good, no principal spillway is
required except where the pond is spring fed or there
are other sources of steady baseflow. In this case, a
trickle tube shall be installed.
Earth spillways have limitations. Use them only where
the soils and topography allow the peak flow to dis-
charge safely at a point well downstream and at a
velocity that does not cause appreciable erosion either
within the spillway or beyond its outlet.
Soil borings generally are required for auxiliary spill-
ways if a natural site with good plant cover is avail-
able. If spillway excavation is required, the investiga-
tions should be thorough enough to determine
whether the soils can withstand reasonable velocities
without serious erosion. Avoid loose sands and other
highly erodible soils.
No matter how well a dam has been built, it will prob-
ably be destroyed during the first severe storm if the
capacity of the spillway is inadequate. The function of
an auxiliary spillway is to pass excess storm runoff
around the dam so that water in the pond does not rise
high enough to damage the dam by overtopping. The
spillways must also convey the water safely to the
outlet channel below without damaging the down-
stream slope of the dam. The proper functioning of a
pond depends on a correctly designed and installed
spillway system.
Auxiliary spillways should have the minimum capacity
to discharge the peak flow expected from a storm of
the frequency and duration shown in table 7 less any
reduction creditable to conduit discharge and deten-
tion storage. After the spillway capacity requirements
are calculated, the permissible velocity must be deter-
mined. Table 8 shows the recommended allowable
velocity for various cover, degree of erosion resis-
tance, and slope of the channel. Table 9 gives the
retardance factors for the expected height of the
vegetation.
Both natural and excavated auxiliary spillways are
used. A natural spillway does not require excavation to
provide enough capacity to conduct the pond outflow
to a safe point of release (fig. 20). The requirements
discussed later for excavated spillways do not apply to
natural spillways, but the capacity must be adequate.
With the required discharge capacity (Q), the end
slope of the embankment (Zl), and the slope of the
natural ground (Z2) known, the maximum depth of
water above the level portion (Hp) can be obtained
from table 10. The depth is added to the elevation of
the spillway crest to determine the maximum eleva-
tion to which water will rise in the reservoir.
Table 7 Minimum spillway design storm
Drainage Effective Storage Minimum design storm
area height Frequency Minimum
of dam!/ duration
(acre) (ft) (acre-ft) (yr) (hr)
20 or less 20 or less Less than 50 10 24
20 or less More than 20 Less than 50 25 24
More than 20 20 or less Less than 50 25 24
All others 50 24
l/ The effective height of the dam is the difference in elevation between the auxiliary spillway crest and the lowest point in the cross section
taken along the centerline of the dam.
27
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Table 8 Permissible velocity for vegetated spillways 1/
Vegetation ----------------- ----- Permissible velocity 2/--------------------
Erosion-resistant soils T Easily eroded soils q/
----------------------Slope of exit channel (%) -------------------
0-5 5-10 0-5 5-10
(ft/s) (ft/s) (ft/s) (ft/s)
Bermudagrass 8 7 6 5
Bahiagrass 8 7 6 5
Buffalograss 7 6 5 4
Kentucky bluegrass 7 6 5 4
Smooth brome 7 6 5 4
Tall fescue 7 6 5 4
Reed canarygrass 7 6 5 4
Sod-forming grass-legume mixtures 5 4 4 3
Lespedeza sericea 3.5 3.5 2.5 2.5
Weeping lovegrass 3.5 3.5 2.5 2.5
Yellow bluestem 3.5 3.5 2.5 2.5
Native grass mixtures 3.5 3.5 2.5 2.5
1/ SCS TP-61
2/ Increase values 10 percent when the anticipated average use of the spillway is not more frequent than once in 5 years, or 25 percent when
the anticipated average use is not more frequent than once in 10 years.
3/ Those with a higher clay content and higher plasticity. Typical soil textures are silty clay, sandy clay, and clay.
4/ Those with a high content of fine sand or silt and lower plasticity, or nonplastic. Typical soil textures are fine sand, silt, sandy loam, and silty
loam.
Table 9 Guide to selection of vegetal retardance
Stand Average height Degree of
of vegetation (in) retardance
Good Higher than 30 A
11 to 24 B
6 to 10 C
2to6 D
Less than 2 E
Fair Higher than 30 B
11 to 24 C
6 to 10 D
2to6 D
Less than 2 E
28
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Figure 20 Plan, profile, and cross section of a natural spillway with vegetation
End slope protected with rock riprap Top of dam
Maximum water elevation
\\\\ III`\? 22 HP Lo aooo
Typical control section
Natural grou
- Spillway crest
HP
/\ ' II II \\
f L
Profile
nd
Wing dike
used to protect
embankment
Level part-?
67
/ moo ?
r Toe of dam
N
Centerline of dam
Embankment to be
perpendicular to slope
Plan view
29
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Table 10 Hp discharge and velocities for natural vegetated spillways with 3:1 end slope (Zi)
Natural Retardance
ground ----- A ----- ----- B - ---- ----- C - ---- ----- D - ---- ----- E ----- ---- Slope ----
slope ZZ Hp Q V Q V Q V Q V Q V Min. Max.
(%) (ft) (ft3/s) (ft/s) (ft3/s) (ft/s) (ft3/s) (ft/s) (ft3/s) (ft/s) (ft3/s) (ft/s) M N
0.5 1.0 19 0.3 28 0.5 47 1.3 68 1.8 130 2.8 0.5 3
1.1 21 .3 35 .5 76 1.5 108 2.1 154 3.0
1.2 29 .4 39 .6 97 1.6 122 2.3 204 3.2
1.3 36 .4 53 .6 125 2.0 189 2.5 250 3.4
1.5 61 .4 87 1.1 210 2.2 291 2.9 393 3.8
1.8 81 .5 187 1.8 384 2.9 454 3.5 651 4.5
2.0 110 .5 286 2.1 524 3.3 749 3.8 860 4.8
1 1.0 10 0.4 16 0.5 31 2.0 45 2.6 64 3.4 1 3
1.1 13 .4 18 .6 50 2.3 63 2.8 90 3.7
1.2 15 .5 21 .8 62 2.5 78 3.1 99 4.0
1.3 22 .6 39 1.0 86 2.7 144 3.4 139 4.3
1.5 40 .7 75 1.8 133 3.1 186 4.0 218 5.1
1.8 56 .8 126 2.3 280 3.8 296 4.5
2.0 98 1.1 184 2.8 328 4.3 389 5.0
2.5 171 2.5 472 4.1 680 5.4
2 1.0 6 0.5 9 0.8 18 2.5 27 3.3 36 4.2 1 3
1.1 7 .7 14 1.0 29 2.8 39 3.6 50 4.5
1.2 9 .8 19 1.1 40 3.1 51 3.9 64 4.9
1.3 13 .9 26 1.6 50 3.4 70 4.3 85 5.3
1.5 21 1.0 39 2.0 70 3.9 109 5.1 127 6.3
1.8 26 1.1 74 2.5 126 4.8 194 5.9
2.0 52 1.3 111 3.2 190 5.4 229 6.4
2.5 88 2.8 238 5.2 339 6.8
3 1.0 4 0.7 7 0.8 15 2.8 21 3.7 28 4.8 1 3
1.1 5 .8 10 .9 24 3.2 31 4.0 38 5.2
1.2 7 .9 14 1.1 33 3.6 41 4.4 49 5.6
1.3 10 1.0 20 1.5 42 3.8 57 4.8 67 6.1
1.5 16 1.2 34 2.8 62 4.4 89 5.7 104 7.2
1.8 23 1.3 57 3.0 112 5.5 143 6.7
2.0 39 1.5 81 3.7 163 6.2 194 7.2
2.5 85 3.1 212 6.0 300 7.8
4 1.2 6 1.0 11 1.4 25 3.9 31 4.8 38 6.1 1 4
1.5 15 1.3 29 3.1 49 4.8 69 5.5 81 7.9
1.8 20 1.4 47 4.1 98 6.1 116 7.3
2.0 30 1.6 65 4.7 139 6.7 161 7.8
2.5 72 3.3 167 6.6 238 8.5
5 1.5 13 1.4 23 3.3 38 5.2 55 6.7 63 8.4 1 5
1.8 17 1.5 37 4.4 76 6.5 95 7.9
2.0 23 1.7 48 5.1 112 7.1 130 8.1
2.5 64 3.7 149 7.1 191 9.2
30
Agriculture Handbook 590
Ponds-Planning, Design, Construction
The following example shows how to use table 10
Given:
Vegetation: good stand of bermudagrass
Height: 6 to 10 inches
Slope of natural ground: 1.0 percent
Solution:
From table 9, determine a retardance of C
From table 10, under natural ground slope
1 percent and retardance C column,
find Q = 88
ft3/s at Hp = 1.3 ft, and
V= 2.7 ft/s.
If the freeboard is 1.0 foot, the top of the dam should
be constructed 2.3 feet higher than the spillway crest.
The velocity is well below the maximum permissible
velocity of 6 feet per second given in table 8. Hp can be
determined by interpolation when necessary. For a Q
greater than that listed in table 10, the spillway should
be excavated according to the information in the next
section, Excavated auxiliary spillways.
Excavated auxiliary spillways-Excavated spill-
ways consist of the three elements shown in figure 21.
The flow enters the spillway through the inlet channel.
The maximum depth of flow (Hp) located upstream
from the level part is controlled by the inlet channel,
level part, and exit channel.
Excavation of the inlet channel or the exit channel, or
both, can be omitted where the natural slopes meet
the minimum slope requirements. The direction of
slope of the exit channel must be such that discharge
does not flow against any part of the dam. Wing dikes,
sometimes called kicker levees or training levees, can
be used to direct the outflow to a safe point of release
downstream.
The spillway should be excavated into the earth for its
full depth. If this is not practical, the end of the dam
and any earthfill constructed to confine the flow
should be protected by vegetation or riprap. The
entrance to the inlet channel should be widened so it
is at least 50 percent greater than the bottom width of
the level part. The inlet channel should be reasonably
short and should be planned with smooth, easy curves
for alignment. It should have a slope toward the reser-
voir of not less than 2.0 percent to ensure drainage and
low water loss at the inlet.
With the required discharge capacity, the degree of
retardance, permissible velocity, and the natural slope
of the exit channel known, the bottom width of the
level and exit sections and the depth of the flow (Hp)
can be computed using the figures in table 11. This
table shows discharge per foot of width. The natural
slope of the exit channel should be altered as little as
possible.
The selection of the degree of retardance for a given
auxiliary spillway depends mainly on the height and
density of the cover chosen (table 9). Generally, the
retardance for uncut grass or vegetation is the one to
use for capacity determination. Because protection
and retardance are lower during establishment and
after mowing, to use a lower degree of retardance
when designing for stability may be advisable.
The following examples show the use of the informa-
tion in table 11:
Example 1 where only one retardance is used for
capacity and stability:
Given:
Q = 87 ft3/s (total design capacity)
So = 4 percent (slope of exit channel determined
from profile, or to be excavated)
L = 50 ft
Earth spillway is to be excavated in an erosion-resis-
tant soil and planted with a sod-forming grass-legume
mixture. After establishment, a good stand averaging
from 6 to 10 inches in height is expected.
Required:
Permissible velocity ([?
Width of spillway (b)
Depth of water in the reservoir above the crest (Hd.
Solution:
From table 8 for sod-forming grass-legume
mixtures, read permissible velocity V= 5 ft /s.
From table 9 for average height of vegetation of 6 to
10 inches, determine retardance C.
31
Agriculture Handbook 590
Ponds-Planning, Design, Construction
For retardance C, enter table 11 from left at
maximum velocity V= 5 ft/s. A 4 percent slope is in
the slope range of 1-6 with Q of 3 ft3/s/ft.
Hp for L of 50 ft = 1.4 ft.
If the freeboard is 1 foot, the spillway should be con-
structed 29 feet wide and 2.4 feet deep.
For retardance C, enter table 11 from left at
maximum velocity V= 5 ft/s. A 4 percent slope is in
the slope range of 1-6 with Qof 3 ft3/s/ft.
Hp for L of 50 ft = 1.4 ft.
If the freeboard is 1 foot, the spillway should be con-
structed 29 feet wide and 2.4 feet deep.
Example 2 where one retardance is used for stability
and another is used for capacity:
Given:
So = 4 percent (slope of exit channel determined
from profile or to be excavated)
L = 50 ft
Earth spillway is to be excavated in a highly erodible
soil and planted with bahiagrass. After establishment a
good stand of 11 to 24 inches is expected.
Required:
Permissible velocity (M
Width of spillway (b)
Depth of water in reservoir above the crest (Hp).
Solution:
From table 8 determine permissible velocity for
bahiagrass in a highly erodible soil that has 8 per-
cent slope V= 5 ft/s.
From table 9, select retardants to be used for stabil-
ity during an establishment period that has a good
stand of vegetation of 2 to 6 inches (retardance D).
Select retardance to be used for capacity for good
stand of vegetation that has a length of
11 to 24 inches (retardance B).
From table 11, enter from left at maximum velocity
V= 5 ft/s. A slope of 6 percent is in the range
for Q = 2 ft3/s/ft.
Then
From table 11, enter q = 2 ft3/s/ft under retardance
B and find Hp for L of 25 ft = 1.4 ft.
If the freeboard is 1 foot, the spillway should be
constructed 50 feet wide and 2.4 feet deep.
Protection against erosion-Protect auxiliary
spillways against erosion by establishing good plant
cover if the soil and climate permit. As soon after
construction as practicable, prepare the auxiliary
spillway area for seeding or sodding by applying
fertilizer or manure. Sow adapted perennial grasses
and protect the seedlings to establish a good stand.
Mulching is necessary on the slopes. Irrigation is often
needed to ensure good germination and growth, par-
ticularly if seeding must be done during dry periods. If
the added cost is justified, sprigging or sodding suitable
grasses, such as bermudagrass, gives quick protection.
32
Agriculture Handbook 590
Figure 21 Excavated earth spillway
portion
Ponds-Planning, Design, Construction
11 Inlet Exit channel
channel l ? -?
I
?-- Embankment
(Note: Neither the location nor
the alignment of the level
portion has to coincide with the
center line of the dam.)
Excavated earth spillway
Plan view of earth spillways
Water surface
InletSeannel \/_\??I1111\

Exit channel
T- Wing dike
4-Embankment
(Note: Use care to keep all
machinery and traffic out of
the spillway discharge area
to protect sod.)
Optional with sod
or riprap on wing dike
Exit channel

L
Profile along centerline
Cross section of level portion
Inlet channel
Definition of terms:
Hp = depth of water in reservoir above crest
L = length of level portion min. 25 It
b = bottom width of spillway
So = slope for exit channel
Se = slope of inlet channel
33
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Table 11 Depth of flow (Hp) and slope range at retardance values for various discharges, velocities, and crest lengths
Maximum Discharge ---------- -------------- Hp-------------- ----- ---- - Slope -----
velocity ---------- -------------- L --------------- ----- Min. Max.
25 50 100 200
(ft/s) (ft3/s/ft) (ft) (ft) (ft) (ft) (%) (%)
Retardance A 3 3 2.3 2.5 2.7 3.1 1 11
4 4 2.3 2.5 2.8 3.1 1 12
4 5 2.5 2.6 2.9 3.2 1 7
5 6 2.6 2.7 3.0 3.3 1 9
6 7 2.7 2.8 3.1 3.5 1 12
7 10 3.0 3.2 3.4 3.8 1 9
8 12.5 3.3 3.5 3.7 4.1 1 10
Retardance B 2 1 1.2 1.4 1.5 1.8 1 12
2 1.25 1.3 1.4 1.6 1.9 1 7
3 1.5 1.3 1.5 1.7 1.9 1 12
3 2 1.4 1.5 1.7 1.9 1 8
4 3 1.6 1.7 1.9 2.2 1 9
5 4 1.8 1.9 2.1 2.4 1 8
6 5 1.9 2.1 2.3 2.5 1 10
7 6 2.1 2.2 2.4 2.7 1 11
8 7 2.2 2.4 2.6 2.9 1 12
Retardance C 2 0.5 0.7 0.8 0.9 1.1 1 6
2 1 0.9 1.0 1.2 1.3 1 3
3 1.25 0.9 1.0 1.2 1.3 1 6
4 1.5 1.0 1.1 1.2 1.4 1 12
4 2 1.1 1.2 1.4 1.6 1 7
5 3 1.3 1.4 1.6 1.8 1 6
6 4 1.5 1.6 1.8 2.0 1 12
8 5 1.7 1.8 2.0 2.2 1 12
9 6 1.8 2.0 2.1 2.4 1 12
9 7 2.0 2.1 2.3 2.5 1 10
10 7.5 2.1 2.2 2.4 2.6 1 12
Retardance D 2 0.5 0.6 0.7 0.8 0.9 1 6
3 1 0.8 0.9 1.0 1.1 1 6
3 1.25 0.8 0.9 1.0 1.2 1 4
4 1.25 0.8 0.9 1.0 1.2 1 10
4 2 1.0 1.1 1.3 1.4 1 4
5 1.5 0.9 1.0 1.2 1.3 1 12
5 2 1.0 1.2 1.3 1.4 1 9
5 3 1.2 1.3 1.5 1.7 1 4
6 2.5 1.1 1.2 1.4 1.5 1 11
6 3 1.2 1.3 1.5 1.7 1 7
7 3 1.2 1.3 1.5 1.7 1 12
7 4 1.4 1.5 1.7 1.9 1 7
8 4 1.4 1.5 1.7 1.9 1 12
8 5 1.6 1.7 1.9 2.0 1 8
10 6 1.8 1.9 2.0 2.2 1 12
34
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Table 11 Depth of flow (HP) and slope range at retardance values for various discharges, velocities, and crest lengths-
Continued.
Maximum Discharge --------- --------------- Hp------------- ------ ---- -Slope-----
velocity --------- --------------- L -------------- ------ Min. Max.
25 50 100 200
VIL/s) (ft3/s/ft) (ft) (ft) (ft) (ft) N (%)
Retardance E 2 0.5 0.5 0.5 0.6 0.7 1 2
3 0.5 0.5 0.5 0.6 0.7 1 9
3 1 0.7 0.7 0.8 0.9 1 3
4 1 0.7 0.7 0.8 0.9 1 6
4 1.25 0.7 0.8 0.9 1.0 1 5
5 1 0.7 0.7 0.8 0.9 1 12
5 2 0.9 1.0 1.1 1.2 1 4
6 1.5 0.8 0.9 1.0 1.1 1 12
6 2 0.9 1.0 1.1 1.2 1 7
6 3 1.2 1.2 1.3 1.5 1 4
7 2 0.9 1.0 1.1 1.2 1 12
7 3 1.2 1.2 1.3 1.5 1 7
8 3 1.2 1.2 1.3 1.5 1 10
8 4 1.4 1.4 1.5 1.7 1 6
10 4 1.4 1.4 1.5 1.7 1 12
35
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Pipes through the dam
Pipe spillways-Protect the vegetation in earth
spillway channels against saturation from spring flow
or low flows that may continue for several days after a
storm. A pipe placed under or through the dam pro-
vides this protection. The crest elevation of the en-
trance should be 12 inches or more below the top of
the control section of the auxiliary spillway.
The pipe should be large enough to discharge flow
from springs, snowmelt, or seepage. It should also
have enough capacity to discharge prolonged surface
flow following an intense storm. This rate of flow
generally is estimated. If both spring flow and pro-
longed surface flow can be expected, the pipe should
be large enough to discharge both.
Drop inlet and hood inlet pipe spillways are commonly
used for ponds.
Figure 22 Drop-inlet pipe spillway with antiseep collar
36
Drop-inlet pipe spillway-A drop-inlet consists of a
pipe barrel (fig. 22) located under the dam and a riser
connected to the upstream end of the barrel. This riser
can also be used to drain the pond if a suitable valve or
gate is attached at its upstream end (fig. 23).
With the required discharge capacity determined, use
table 12 or 13 to select an adequate pipe size for the
barrel and riser. Table 12 is for barrels of smooth
pipe, and table 13 is for barrels of corrugated metal
pipe. The diameter of the riser must be somewhat
larger than the diameter of the barrel if the tube is to
flow full. Recommended combinations of barrel and
riser diameters are shown in the tables. In these tables
the total head is the vertical distance between a point
1 foot above the riser crest and the centerline of the
barrel at its outlet end. Because pipes of small diam-
eter are easily clogged by trash and rodents, no pipe
smaller than 6 inches in diameter should be used for
the barrel.
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Figure 23 Drop-inlet pipe spillways
(a) With sand-gravel filter
Trash rack
(b) With antiseep collar
Trash rack
Filter diaphragm
Ground
surface
37
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Table 12 Discharge values for smooth pipe drop inlets 1/
Total head Ratio of barrel diameter to riser diameter (in)
6:8 8:10 10:12 12:15 15:24 18:36
(ft) (ft3/s) (ft3/s) (ft3/s) (ft3/s) (ft3/s) (ft3/s)
6 1.54 3.1 5.3 8.1 13.6 20.6
8 1.66 3.3 5.7 8.9 14.8 22.5
10 1.76 3.5 6.1 9.6 15.8 24.3
12 1.86 3.7 6.5 10.2 16.8 26.1
14 1.94 3.9 6.8 10.7 17.8 27.8
16 2.00 4.0 7.0 11.1 18.6 29.2
18 2.06 4.1 7.2 11.5 19.3 30.4
20 2.10 4.2 7.4 11.8 19.9 31.3
22 2.14 4.3 7.6 12.1 20.5 32.2
24 2.18 4.4 7.8 12.4 21.0 33.0
26 2.21 4.5 8.0 12.6 21.5 33.8
1/ Length of pipe barrel used in calculations is based on a dam with a 12-foot top width and 2.5:1 side slopes. Discharge values are based on a
minimum head on the riser crest of 12 inches. Pipe flow based on Manning's n = 0.012.
Table 13 Discharge values for corrugated metal pipe drop inlets 1/
Total head Ratio of barrel diameter to riser diameter (in)
6:8 8:10 10:12 12:15 15:21 18:24
(ft) (ft3/s) (ft3/s) (ft3/s) (ft3/s) (ft3/s) (ft3/s)
6 0.85 1.73 3.1 5.1 8.8 14.1
8 0.90 1.85 3.3 5.4 9.4 15.0
10 0.94 1.96 3.5 5.7 9.9 15.9
12 0.98 2.07 3.7 6.0 10.4 16.7
14 1.02 2.15 3.8 6.2 10.8 17.5
16 1.05 2.21 3.9 6.4 11.1 18.1
18 1.07 2.26 4.0 6.6 11.4 18.6
20 1.09 2.30 4.1 6.7 11.7 18.9
22 1.11 2.34 4.2 6.8 11.9 19.3
24 1.12 2.37 4.2 6.9 12.1 19.6
26 1.13 2.40 4.3 7.0 12.3 19.9
I/ Length of pipe barrel used in calculations is based on a dam with a 12-foot top width and 2.5:1 side slopes. Discharge values are based on a
minimum head on the riser crest of 12 inches. Pipe flow based on Manning's n = 0.012.
38
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Hood-inlet pipe spillway-A hood-inlet consists of a
pipe laid in the earthfill (fig. 24). The inlet end of the
pipe is cut at an angle to form a hood. An antivortex
device, usually metal, is attached to the entrance of
the pipe to increase the hydraulic efficiency of the
tube. Typical installations of hood inlets and details of
the antivortex device are shown in figure 25. Often a
hood-inlet can be built at less cost than a drop-inlet
because no riser is needed. The major disadvantage of
this kind of pipe spillway is that it cannot be used as a
drain.
Figure 24 Dam with hooded inlet pipe spillway
(a) With sand-gravel filter
Hooded
inlet
V`
Support for cantilever
outlet (optional)
Rock
cover
Filter diaphragm
(b) With antiseep collar
am
Hooded Antiseep
inlet collar
Support for cantilever
outlet (optional)
Y -
Pond
39
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Figure 25 Pipe inlet spillways that have trash rack and antivortex baffle
A ntk-t-
Steel
trast
Steel rods
2-in by 12-in
plank
co
.n by 4-in
st
ron
40
Agriculture Handbook 590
Ponds-Planning, Design, Construction
The required diameter for a hood-inlet pipe can be
selected from table 14 or 15 after estimating the dis-
charge capacity, Q, and determining the total head, H.
The tables also show the minimum head, h, required
above the invert or crest elevation of the pipe en-
trance. Unless you provide this minimum head, the
pipe will not flow full.
Pipe made of cast iron, smooth steel, concrete, plastic,
or corrugated metal is suitable for either kind of pipe
spillway. All joints must be watertight. A concrete
cradle or bedding is needed for concrete pipe to en-
sure a firm foundation and good alignment of the
conduit. Seal the joints of concrete pipe with an ap-
proved type of rubber gasket to give them the desired
amount of flexibility. For all pipe spillways, use new
pipe or pipe so slightly used that it may be considered
equivalent to new pipe.
To retard seepage through the embankment along the
outside surface of the pipe, compact the fill around the
pipe and use a filter and drainage diaphragm around
the pipe like that shown in figure 24.
One filter and drainage diaphragm should be used
around any structure that extends through the em-
bankment to the downstream slope. The diaphragm
should be located downstream of the centerline of a
homogeneous embankment or downstream of the
cutoff trench. The diaphragm should be a minimum of
3 feet thick and extend around the pipe surface a
minimum of 2 times the outside diameter of the pipe
(2Do). When a cradle or bedding is used under the
pipe, the vertical downward 2Do is measured from the
bottom of the cradle or bedding. If bedrock is encoun-
tered within the 2Do measurement, the diaphragm
should terminate at the bedrock surface. The location
Table 14 Minimum head, h (ft), required above the invert of hood inlets to provide full flow, Q (ft3/s), for various sizes of
smoo th pipe and values of total head, Hl/
Total head Diameter of pipe in inches
(ft) 6 8 10 12 15 18
6 h= 0.63 h= 0.85 h=1.04 h= 1.23 h= 1.54 h=1.82
Q =1.63 Q =3.0 Q=5.3 Q= 8.5 Q= 14.0 Q=21.2
8 h= 0.65 h= 0.86 h=1.06 h= 1.27 h= 1.57 h=1.87
Q =1.78 Q =3.5 Q=6.0 Q= 9.3 Q= 15.5 Q=23.3
10 h= 0.66 h=0.87 h=1.08 h= 1.30 h= 1.60 h=1.91
Q =1.93 Q =3.8 Q=6.6 Q= 10.2 Q =17.0 Q=25.4
12 h= 0.67 h= 0.88 h=1.09 h= 1.32 h= 1.63 h=1.94
Q =2.06 Q =4.1 Q=7.1 Q=10.9 Q=18.3 Q=27.5
14 h= 0.67 h= 0.89 h=1.11 h= 1.33 h= 1.65 h=1.96
Q =2.18 Q =4.3 Q=7.5 Q= 11.6 Q =19.5 Q=29.4
16 h= 0.68 h= 0.90 h=1.13 h= 1.35 h= 1.67 h=1.98
Q =2.28 Q =4.5 Q=7.8 Q= 12.2 Q= 20.5 Q=31.0
18 h= 0.69 h= 0.91 h=1.14 h= 1.36 h= 1.69 h=2.00
Q =2.36 Q =4.7 Q=8.1 Q= 12.7 Q =21.4 Q=32.5
20 h= 0.69 h= 0.92 h=1.15 h= 1.37 h= 1.70 h=2.02
Q =2.43 Q =4.9 Q=8.4 Q= 13.2 Q= 22.2 Q=33.9
22 h= 0.70 h= 0.93 h=1.16 h=1.38 h=1.71 h=2.04
Q =2.50 Q =5.0 Q=8.7 Q= 13.6 Q= 23.0 Q=35.1
24 h= 0.70 h=0.93 h=1.16 h= 1.39 h= 1.72 h=2.05
Q =2.56 Q =5.1 Q=9.0 Q= 14.0 Q= 23.7 Q=36.3
26 h=0.71 h= 0.94 h=1.17 h= 1.40 h= 1.73 h=2.07
Q =2.60 Q =5.2 Q=9.3 Q= 14.4 Q=24.4 Q=37.5
l/ Length of pipe used in calculations is based on a dam with a 12-foot top width and 2.5:1 side slopes. Pipe flow based on Manning's n = 0.012.
41
Agriculture Handbook 590
Ponds-Planning, Design, Construction
of the diaphragm should never result in a minimum
soil cover over a portion of the diaphragm measured
normal to the nearest embankment surface of less
than 2 feet. If this requirement is exceeded, the filter
and drainage diaphragm should be moved upstream
until the 2-foot minimum is reached. The outlet for the
filter and drainage diaphragm should extend around
the pipe surface a minimum of 1.5 times the outside
diameter of the pipe (1.5Do) that has 1 foot around the
pipe being a minimum.
In most cases where the embankment core consists of
fine-grained materials, such as sandy or gravely silts
and sandy or gravely clay (15 to 85 percent passing the
No. 200 sieve), an aggregate conforming to ASTM C-33
fine concrete aggregate is suitable for the filter and
drainage diaphragm material. A fat clay or elastic silt
(more than 85 percent passing No. 200 sieve) core
requires special design considerations, and an engi-
neer experienced in filter design should be consulted.
Using a filter and drainage diaphragm has many advan-
tages. Some are as follows:
• They provide positive seepage control along
structures that extend through the fill.
• Unlike concrete antiseep collars, they do not
require curing time.
Installation is easy with little opportunity for
constructed failure. The construction can consist
mostly of excavation and backfilling with the
filter material at appropriate locations.
Antiseep collars can be used instead of the filter and
drainage diaphragm. Antiseep collars have been used
Table 15 Minimum head, h (ft), required above the invert of hood inlets to provide full flow, Q (ft3/s), for various sizes of
corrugated pipe and values of total head, H1/
Total head Diameter of pipe in inches
(ft) 6 8 10 12 15 18
6 h=0.59 h=0.78 h= 0.97 h=1.17 h= 1.46 h=1.75
Q=0.92 Q=1.9 Q =3.3 Q=5.3 Q= 9.1 Q=14.5
8 h=0.59 h=0.79 h= 0.98 h=1.18 h= 1.48 h=1.77
Q=1.00 Q=2.1 Q =3.6 Q=5.8 Q=10.0 Q=16.0
10 h=0.60 h=0.79 h=0.99 h=1.19 h= 1.49 h=1.79
Q=1.06 Q=2.2 Q =3.9 Q=6.3 Q= 10.9 Q=17.3
12 h=0.60 h=0.80 h= 1.00 h=1.20 h= 1.50 h=1.80
Q=1.12 Q=2.3 Q =4.2 Q=6.7 Q= 11.6 Q=18.5
14 h=0.61 h=0.81 h= 1.01 h=1.21 h= 1.51 h=1.82
Q=1.18 Q=2.4 Q =4.4 Q=7.1 Q= 12.2 Q=19.6
16 h=0.61 h=0.81 h=1.01 h=1.21 h= 1.52 h=1.82
Q=1.22 Q=2.5 Q =4.6 Q=7.4 Q= 12.7 Q=20.5
18 h=0.61 h=0.81 h= 1.02 h=1.22 h= 1.53 h=1.83
Q=1.26 Q=2.6 Q =4.8 Q=7.6 Q= 13.2 Q=21.3
20 h = 0.62 h = 0.82 h = 1.03 h = 1.23 h = 1.54 h = 1.85
Q=1.30 Q=2.7 Q =4.9 Q=7.8 Q=13.7 Q=21.9
22 h=0.62 h=0.83 h= 1.03 h=1.24 h= 1.55 h=1.86
Q=1.33 Q=2.8 Q =5.0 Q=8.0 Q= 14.1 Q=22.5
24 h=0.63 h=0.83 h= 1.04 h=1.25 h= 1.56 h=1.88
Q=1.35 Q=2.8 Q =5.1 Q=8.2 Q=14.5 Q=23.0
26 h=0.63 h=0.84 h= 1.05 h=1.26 h= 1.58 h=1.89
Q=1.37 Q=2.9 Q =5.2 Q=8.3 Q= 14.7 Q=23.4
1/ Length of pipe used in calculations is based on a dam with a 12-foot top width and 2.5:1 side slopes. Pipe flow based on Manning's n = 0.025
42
Agriculture Handbook 590
Ponds-Planning, Design, Construction
with pipe spillways for many years. More fabricated
materials are required for this type of installation.
Both types of seepage control are acceptable; in either
case, proper installation is imperative.
If an antiseep collar is used, it should extend into the
fill a minimum of 24 inches perpendicular to the pipe.
If the dam is less than 15 feet high, one antiseep collar
at the centerline of the fill is enough. For higher dams,
use two or more collars equally spaced between the
fill centerline and the upstream end of the conduit
when a hood-inlet pipe is used. If a drop-inlet pipe is
used, the antiseep collars should be equally spaced
between the riser and centerline of the fill.
Use trash racks to keep pipes from clogging with trash
and debris. Of the many kinds of racks that have been
used, the three shown in figure 25 have proved the
most successful.
Extend the pipe 6 to 10 feet beyond the downstream
toe of the dam to prevent damage by the flow of water
from the pipe. For larger pipes, support the extension
with a timber brace.
Drainpipes-Some state regulatory agencies require
that provision be made for draining ponds completely
or for fluctuating the water level to eliminate breeding
places for mosquitoes. Whether compulsory or not,
provision for draining a pond is desirable and recom-
mended. It permits good pond management for fish
production and allows maintenance and repair with-
out cutting the fill or using siphons, pumps, or other
devices to remove the water. Install a suitable gate or
other control device and extend the drainpipe to the
upstream toe of the dam to drain the pond.
Water-supply pipes-Provide a water-supply pipe
that runs through the dam if water is to be used at
some point below the dam for supplying a stockwater
trough, for irrigation, or for filling an orchard spray
tank (fig. 26). This pipe is in addition to the principal
spillway. A water-supply pipe should be rigid and have
watertight joints, a strainer at its upper end, and a
valve at its outlet end. For a small rate of flow, such as
that needed to fill stockwater troughs, use steel or
plastic pipe that is 1-1/2 inches in diameter. For a larger
rate of flow, such as that needed for irrigation, use
steel, plastic, or concrete pipe of larger diameter.
Water-supply pipes also should have watertight joints
and antiseep collars or a filter and drainage diaphragm.
43
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Figure 26 Water is piped through the dam's drainpipe to a stockwater trough
(a) Pipe with sand-gravel filter
Extended pipe above water level
to show location of intake
I _ -
/-Bell tile around valve and
pipe for suitable housing
Riser with
1/4-inch holes
(b) Pipe with antiseep collars
Extended pipe above water level
to show location of intake
Corrugated metal
pipe with 1-inch holes.
Pipe filled with coarse
gravel
Riser with
1/4-inch holes - r i
6-inch concrete base I Core fill
Filter diaphragm Sand-gravel filter
Bell tile around valve and
pipe for suitable housing
Valve Trough
?4 1_? _
Union
Cap connection
Control valve may be used
for other purposes
44
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Planning an earthfill dam
Foundations-You can build a safe earthfill dam on
almost any foundation if you thoroughly investigate
the foundation and adapt the design and construction
to the conditions. Some foundation conditions require
expensive construction measures that cannot be
justified for small ponds.
The most satisfactory foundation consists of soil
underlain at a shallow depth by a thick layer of rela-
tively impervious consolidated clay or sandy clay. If a
suitable layer is at or near the surface, no special
measures are needed except removing the topsoil and
scarifying or disking to provide a bond with the mate-
rial in the dam.
If the foundation is sand or a sand-gravel mixture and
there is no impervious clay layer at a depth that can be
reached economically with available excavating equip-
ment, an engineer should design the dam. Although
such foundations may be stable, corrective measures
are needed to prevent excessive seepage and possible
failure. A foundation, consisting of or underlain by a
highly plastic clay or unconsolidated material requires
careful investigation and design to obtain stability. If
the foundation consists of such materials, consult an
engineer.
Water impounded on a bedrock foundation seldom
gives cause for concern unless the rock contains
seams, fissures, or crevices through which water may
escape at an excessive rate. Where rock is in the
foundation, investigate the nature of the rock carefully.
Cutoffs-If the dam's foundation is overlain by allu-
vial deposits of pervious sands and gravels at or near
the surface and rock or clay at a greater depth, seep-
age in the pervious stratum must be reduced to pre-
vent possible failure of the dam by piping. To prevent
excessive seepage, you need a cutoff to join the imper-
vious stratum in the foundation with the base of the dam.
The most common kind of cutoff is made of com-
pacted clayey material. A trench is excavated along
the centerline of the dam deep enough to extend well
into the impervious layer (fig. 27). This trench extends
into and up the abutments of the dam as far as there is
any pervious material that might allow seepage. The
bottom of the trench should be no less than 8 feet
wide (or the bulldozer blade width, whichever is
greater), and the sides no steeper than 1.5:1. Fill the
trench with successive thin layers (9-inch maximum)
of clay or sandy clay material. Compact each layer
thoroughly at near-optimum moisture conditions
before placing the next layer. The moisture content is
adequate for compaction when the material can be
formed into a firm ball that sticks together and re-
mains intact when the hand is vibrated violently and
no free water appears.
Top width and alignment-For dams less than 10
feet high, a conservative minimum top width is 6 feet.
As the height of the dam increases, increase the top
width. The recommended minimum top width for
earth embankments of various heights is:
Height of dam Minimum top width
(ft) (ft)
Under 10 6
11 to 14 8
15 to 19 10
20 to 24 12
25 to 34 14
If the top of the embankment is to be used for a road-
way, provide for a shoulder on each side of the road-
way to prevent raveling. The top width should be at
least 16 feet. In some situations a curved dam align-
Figure 27 A core trench is cut on the centerline of a dam
45
Agriculture Handbook 590
Ponds-Planning, Design, Construction
ment is more desirable than a straight alignment.
Curvature can be used to retain existing landscape
elements, reduce the apparent size of the dam, blend
the dam into surrounding natural landforms, and
provide a natural-appearing shoreline.
Side slopes-The side slopes of a dam depend prima-
rily on the stability of the fill and on the strength and
stability of the foundation material. The more stable
the fill material, the steeper the side slopes. Unstable
materials require flatter side slopes. Recommended
slopes for the upstream and downstream faces of
dams built of various materials are shown in table 16.
For stability, the slopes should not be steeper than
those shown in table 16, but they can be flatter as long
as they provide surface drainage. The side slopes need
not be uniform, but can be shaped to blend with the
surrounding landforms (fig. 28).
Finish-grading techniques used to achieve a smooth
landform transition include slope rounding and slope
warping. Slope rounding is used at the top and bottom
of cuts or fills and on side slope intersections. Slope
warping is used to create variety in the horizontal and
vertical pitch of finished slopes (fig. 29). Additional fill
can be placed on the backslope and abutments of the
dam, if needed, to achieve this landform transition.
Freeboard-Freeboard is the additional height of the
dam provided as a safety factor to prevent overtopping
by wave action or other causes. It is the vertical dis-
tance between the elevation of the water surface in the
pond when the spillway is discharging at designed
depth and the elevation of the top of the dam after all
Table 16 Recommended side slopes for earth dams
Slope
Fill material Upstream Downstream
Clayey sand, clayey gravel, sandy 3:1 2:1
clay, silty sand, silty gravel
Silty clay, clayey silt 3:1 3:1
settlement. If your pond is less than 660 feet long,
provide a freeboard of no less than 1 foot. The mini-
mum freeboard is 1.5 feet for ponds between 660 and
1,320 feet long, and is 2 feet for ponds up to a half mile
long. For longer ponds an engineer should determine
the freeboard.
Settlement allowance-Settlement or consolidation
depends on the character of the materials in both the
dam and the foundation and on the construction
method. To allow for settlement, build earth dams
somewhat higher than the design dimensions. If your
dam is adequately compacted in thin layers under
good moisture conditions, there is no reason to expect
any appreciable settlement in the dam itself, but the
foundation may settle. For a compacted fill dam on
unyielding foundation, settlement is negligible.
Most foundations are yielding, and settlement may
range from 1 to 6 percent of the height of the dam,
mainly during construction. The settlement allowance
for a rolled-fill dam should be about 5 percent of the
designed dam height. In other words, the dam is built
5 percent higher than the designed height. After settle-
ment, the height of the dam will be adequate. Most
pond dams less than 20 feet high, however, are not
rolled fill. For these dams the total settlement allow-
ance should be about 10 percent.
Estimating the volume of the earthfiII-After
planning is completed, estimate the number of cubic
yards of earthfill required to build the dam. Also esti-
mate excavation yardage in foundation stripping, core
trench excavation, and any other significant excava-
tions. This helps predict the cost of the dam
Figure 28 Dam side slopes are curved and shaped to
blend with surrounding topography
46
Agriculture Handbook 590
Ponds-Planning, Design, Construction
and serves as a basis for inviting bids and for awarding
a construction contract. The estimate of the volume of
earthfill should include
• volume in the dam itself including the allowance
for settlement,
• volume required to backfill the cutoff trench,
• volume required to backfill stream channels or
holes in the foundation area, and
• any other volume of earthfill the contractor is
required to move.
Volume estimates for dams generally are made of the
required number of cubic yards of earthfill in place.
Probably the most efficient method of estimating the
volume of earthfill is the sum-of-end-area method. The
ground surface elevations at all points along the
centerline of the dam where the slope changes signifi-
cantly are established by the centerline profile. With
the settled top elevation of the dam established, you
Figure 29 Finished grading techniques
can obtain the settle fill height at each of these points
by subtracting the ground surface elevation from the
settle top elevation. With the fill heights, side slopes,
and top width established, find the end areas at each
of these stations along the centerline in table 17.
For example, assume that a dam has slopes of 3:1 on
both upstream and downstream sides and a top width
of 12 feet. For a point along the centerline where the
fill is 15 feet high, the table shows that the end area at
that point is 675 plus 180, or 855 square feet. The
number of cubic yards of fill between two points on
the centerline of the dam is equal to the sum of the end
areas at those two points multiplied by the distance
between these points and divided by 54. The total
volume of earthfill in the dam is the sum of all such
segments. A sample volume estimate illustrating the
use of the sum-of-end-areas method is shown in table 18.
(a) Slope rounding (b) Slope warping
This This
Not this Not this
47
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Table 17 End areas in square feet of embankment sections for different side slopes and top widths 1/
---- --------- Side slopes- ------ ------- ------------Top width (ft) ------------
2.5:1 2.5:1 3:1 3.5:1 4:1
Fill height 2.5:1 3:1 3:1 3.5:1 4:1 8 10 12 14 16
(ft) 2:1 2:1 2.5:1 3:1 3:1
3:1 3.5:1 3.5:1 4:1 5:1
1.0 3 3 3 4 4 8 10 12 14 16
1.2 4 4 4 5 6 10 12 14 17 19
1.4 5 5 6 7 8 11 14 17 20 22
1.6 6 7 8 9 10 13 16 19 22 26
1.8 8 9 10 11 13 14 18 22 25 29
2.0 10 11 12 14 16 16 20 24 28 32
2.2 12 13 15 17 19 18 22 27 31 35
2.4 14 16 17 20 23 19 24 29 34 39
2.6 17 19 20 24 27 21 26 31 36 42
2.8 20 22 23 27 31 22 28 34 39 45
3.0 22 25 27 32 36 24 30 36 42 48
3.2 26 28 31 36 41 26 32 38 45 51
3.4 29 32 35 40 46 27 34 41 47 55
3.6 32 36 39 45 52 29 36 43 50 58
3.8 36 40 43 50 58 30 38 46 53 61
4.0 40 44 48 56 64 32 40 48 56 64
4.2 44 49 53 62 71 34 42 50 59 67
4.4 48 53 58 68 77 35 44 53 61 71
4.6 53 58 63 74 85 37 46 55 64 74
4.8 57 63 69 81 92 38 48 57 67 77
5.0 62 69 75 87 100 40 50 60 70 80
5.2 67 74 81 94 108 42 52 62 73 83
5.4 73 80 87 102 117 43 54 65 75 87
5.6 78 86 94 110 125 45 56 67 78 90
5.8 84 93 101 118 135 46 58 69 81 93
6.0 90 99 108 126 144 48 60 72 84 96
6.2 96 106 115 135 154 50 62 74 87 99
6.4 102 113 123 143 164 51 64 77 89 103
6.6 109 120 131 152 174 53 66 79 92 106
6.8 116 128 139 162 185 54 68 81 95 109
7.0 123 135 147 172 196 56 70 84 98 112
7.2 130 143 156 182 207 58 72 86 101 115
7.4 138 152 165 193 219 59 74 89 103 119
7.6 145 159 174 203 231 61 76 91 106 122
7.8 153 168 183 214 243 62 78 93 109 125
8.0 160 176 192 224 256 64 80 96 112 128
8.2 169 185 202 235 269 66 82 98 115 131
8.4 177 194 212 247 282 67 84 101 117 135
8.6 186 204 222 259 296 69 86 103 120 138
8.8 194 213 232 271 310 70 88 105 123 141
See footnote at end of table.
48
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Table 17 End areas in square feet of embankment sections for different side slopes and top widths 1/-Continued.
-------------Side slopes -------------- ------------ Towidth ft --
2.5:1 2.5:1 3:1 3.5:1 4:1
Fill height 2.5:1 3:1 3:1 3.5:1 4:1 8 10 12 14 16
(ft) 2:1 2:1 2.5:1 3:1 3:1
3:1 3.5:1 3.5:1 4:1 5:1
9.0 203 223 243 283 324 72 90 108 126 144
9.2 212 233 254 296 339 74 92 110 129 147
9.4 222 244 266 310 353 75 94 113 131 151
9.6 231 254 277 323 369 77 96 115 134 154
9.8 241 265 289 337 384 78 98 117 137 157
10.0 250 275 300 350 400 80 100 120 140 160
10.2 260 286 313 364 416 102 122 143 163
10.4 271 298 325 379 433 104 125 145 167
10.6 281 309 338 394 449 106 127 148 170
10.8 292 321 350 409 467 108 129 151 173
11.0 302 333 363 424 484 110 132 154 176
11.2 313 344 376 440 502 112 134 157 179
11.4 325 357 390 456 520 114 137 159 183
11.6 336 370 404 472 538 116 139 162 186
11.8 348 383 418 488 557 118 141 165 189
12.0 360 396 432 504 576 120 144 168 192
12.2 372 409 447 522 595 122 146 171 195
12.4 385 424 462 539 615 124 149 173 199
12.6 397 437 477 557 635 126 151 176 202
12.8 410 451 492 574 655 128 153 179 205
13.0 422 465 507 592 676 130 156 182 208
13.2 436 479 523 610 697 132 158 185 211
13.4 449 494 539 629 718 134 161 187 215
13.6 463 509 555 648 740 136 163 190 218
13.8 476 523 571 667 762 138 166 193 221
14.0 490 539 588 686 784 140 168 196 224
14.2 505 555 605 706 807 142 170 199 227
14.4 519 570 622 726 829 144 173 202 230
14.6 534 586 639 746 853 146 175 204 234
14.8 548 602 657 767 876 148 178 207 237
15.0 563 619 675 788 900 150 180 210 240
15.2 578 635 693 809 924 152 182 213 243
15.4 594 653 711 830 949 154 185 216 246
15.6 609 669 730 852 973 156 187 218 250
15.8 625 687 749 874 999 158 190 221 253
16.0 640 704 768 896 1,024 160 192 224 256
16.2 656 722 787 919 1,050 194 227 259
16.4 673 740 807 942 1,076 197 230 262
16.6 689 758 827 965 1,102 199 232 266
16.8 706 776 847 988 1,129 202 235 269
17.0 723 795 867 1,012 1,156 204 238 272
See footnote at end of table.
49
Agriculture Handbook 590 Ponds-Planning, Design, Construction
Table 17 End areas in square feet of embankment sections for different side slopes and top widths 1/-Continued.
Fill height
(ft)
-------------Side slopes-------------- ------------Top width (ft) ------------
2.5:1 2.5:1 3:1 3.5:1 4:1
2.5:1 3:1 3:1 3.5:1 4:1 8 10 12 14 16
2:1 2:1 2.5:1 3:1 3:1
3:1 3.5:1 3.5:1 4:1 5:1
17.2 740 814 888 1,036 1,183 206 241 275
17.4 757 833 909 1,060 1,211 209 244 278
17.6 774 852 930 1,084 1,239 211 246 282
17.8 792 871 951 1,109 1,267 214 249 285
18.0 810 891 972 1,134 1,296 216 252 288
18.2 828 911 994 1,160 1,325 218 255 291
18.4 846 931 1,016 1,186 1,354 221 258 294
18.6 865 951 1,038 1,212 1,384 223 260 298
18.8 884 972 1,060 1,238 1,414 226 263 301
19.0 903 993 1,083 1,264 1,444 228 266 304
19.2 922 1,014 1,106 1,291 1,475 230 269 307
19.4 941 1,035 1,129 1,318 1,505 233 272 310
19.6 960 1,056 1,152 1,345 1,537 235 274 314
19.8 980 1,078 1,176 1,372 1,568 238 277 317
20.0 1,000 1,100 1,200 1,400 1,600 240 280 320
20.2 1,020 1,122 1,224 1,428 1,632 242 283 323
20.4 1,040 1,144 1,248 1,457 1,665 245 286 326
20.6 1,061 1,167 1,273 1,486 1,697 247 288 330
20.8 1,082 1,190 1,298 1,515 1,731 250 291 333
21.0 1,103 1,213 1,323 1,544 1,764 252 294 336
21.2 1,124 1,236 1,348 1,574 1,798 254 297 339
21.4 1,145 1,254 1,374 1,604 1,832 257 300 342
21.6 1,166 1,283 1,400 1,634 1,866 259 302 346
21.8 1,188 1,307 1,426 1,664 1,901 262 305 349
22.0 1,210 1,331 1,452 1,694 1,936 264 308 352
22.2 1,232 1,356 1,479 1,725 1,971 266 311 355
22.4 1,254 1,380 1,506 1,756 2,007 269 314 358
22.6 1,277 1,405 1,533 1,788 2,043 271 316 362
22.8 1,300 1,430 1,560 1,820 2,079 274 319 365
23.0 1,323 1,455 1,587 1,852 2,116 276 322 368
l/ To find the end area for any fill height, add square feet given under staked side slopes to that under the top width for total section. Example:
6.4-foot 3:1 front and back slopes, 14-foot top width -123 plus 89, or 212 square feet for the section. Any combination of slopes that adds to
5, 6, or 7 may be used. A combination of 3.5:1 front and 2.5:1 back gives the same results as 3:1 front and back.
50
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Table 18 Volume of material needed for the earthfill
Station Ground elevation Fill height 1/ End area ?/ Sum of end areas Distance Double volume
(ft) (ft) (ft) (ft2) (ft') (ft) (ft3)
0+50 35.0 0 0
44 18 792
+68 32.7 2.3 44
401 32 12,832
1+00 25.9 9.1 357
1,066 37 39,442
+37 21.5 13.5 709
1,564 16 25,024
+53 20.0 15.0 855
1,730 22 38,060
+75 19.8 15.2 875
1,781 25 44,525
2+00 19.5 15.5 906
1,730
1, 19 32,870
+19 20.3 14.7 824
1,648
1, 13 21,424
+32 20.3 14.7 824
1,805
1, 4 7,220
+36 18.8 16.2 981
2,030
2, 4 8,120
+40 18.2 16.8 1,049
2,064 3 6,192
+43 18.5 16.5 1,015
1,911
1,91 3 5,733
+46 19.6 15.4 896
1,771
1, 13 23,023
+59 19.8 15.2 875
1,650 41 67,650
3+00 20.8 14.2 775
1,023 35 35,805
+ 35 27.7 7.3 248
324 25 8,100
+60 31.6 3.4 76
76 36 2,736
3+96 35.0 .0 0
Total 379,5481/
l/ Elevation of top of dam without allowance for settlement.
2/ End areas based on 12-foot top width and 3:1 slopes on both sides.
3/ Divide double volume in cubic feet by 54 to obtain volume in cubic yards; for example,
379,548 = 7, 029 yd 3
54
Allowance for settlement (10%) = 703 yd3
Total volume = 7.732 yd?
51
Agriculture Handbook 590
Ponds-Planning, Design, Construction
The sample volume estimate of 7,732 cubic yards
includes only the volume of earth required to complete
the dam itself. Estimate the volume of earth required
to backfill the core trench, old stream channels, and
other required excavation and add it to the estimate
for the dam. Also include an estimate of additional fill
to be placed on the backslope and abutments. For
example, assume that, in addition to the volume
shown in table 18, there is a cutoff trench to be back-
filled. The dimensions of the trench are:
Average depth = 4.0 ft
Bottom width = 8.0 ft
Side slopes =1.5:1
Length = 177 ft
Compute the volume of backfill as follows:
End area = [ w+ (z x d)] d [Eq. 41
(End area x 1) Volume = [Eq. 5]
27
where:
d = average depth
w =bottom width
I = length
z = side slopes
End area = [8 + (1.5 x 4)]4 = 56 ft2
Volume = 56 27 77 = 367 yd3
Add this to the volume required for the dam and the
total volume is 7,732 plus 367, or 8,099 cubic yards.
This 8,099 cubic yards represents the required com-
pacted volume. To account for shrinkage resulting
from compaction, a minimum of 1.5 times this amount
is generally necessary to have available in the borrow
areas and required excavations. In this example you
need a minimum of 12,148 cubic yards available to
construct the dam.
Drawings and specifications-Record on the engi-
neering drawings all planning information that would
affect the construction of the dam. These drawings
should show all elevations and dimensions of the dam,
the dimensions and extent of the cutoff trench and
other areas requiring backfill, the location and dimen-
sions of the principal spillway and other planned
appurtenances, and any other pertinent information.
The drawings should also include a list of the esti-
mated quantity and kind of building materials required.
The construction and material specifications state the
extent and type of work, site specific details, material
quality, and requirements for prefabricated materials.
Observe all land disturbance laws by including tempo-
rary protective measures during construction to mini-
mize soil erosion and sedimentation.
Unless you have all the necessary equipment, you will
need to employ a contractor to build the pond. You
may wish to receive bids from several contractors to
be sure that you are getting the job done at the lowest
possible cost. A set of drawings and specifications
shows what is to be done. This provides a basis for
contractors to bid on the proposed work, allows fair
competition among bidders, and states the conditions
under which the work is to be done. The specifications
should
• give all the information not shown on the draw-
ings that is necessary to define what is to be done,
• prescribe how the work is to be done if such
direction is required,
• specify the quality of material and workmanship
required, and
• define the method of measurement and the unit
of payment for the various items of work that
constitute the whole job.
Construction work of the quality and standards de-
sired will not result unless there is a clear understand-
ing of these requirements between the owner and the
contractor. For these reasons specifications should be
prepared for all ponds for which the owners award the
construction contracts.
Assistance in preparing drawings and specifications is
available from your local soil conservation district,
NRCS specialists, or private consultants.
52
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Staking for construction
Each job must be adequately and clearly staked before
construction is started. Staking transmits the informa-
tion on the drawings to the job site. This information
locates the work and provides the lines, grade, and
elevations required for construction in accordance
with the drawings. Consider the contractor's wishes in
staking so that he can make the most effective use of
the stakes. The quality and appearance of the com-
pleted job reflect the care used in staking. The staking
should be done by an engineer or other qualified person.
The areas to be cleared generally consist of the dam
site, the auxiliary spillway site, the borrow area, and
the area over which water is to be impounded. Mark
each area clearly with an adequate number of stakes.
In the pond area, locate the proposed water line with a
level and surveying rod. This provides a base line from
which clearing limits can be established.
To locate the dam, set stakes along its centerline at
intervals of 100 feet or less. (Generally this has been
done during the initial planning survey.) Then set the
fill and slope stakes upstream and downstream from
the centerline stakes to mark the points of intersection
of the side slopes with the ground surface and to mark
the work area limits of construction. These stakes also
establish the height of the dam.
To locate the earth auxiliary spillway, first stake the
centerline and then set cut and slope stakes along the
lines of intersection of the spillway side slopes with
the natural ground surface.
If fill material must be obtained from a borrow area,
this area must be clearly marked. Set cut stakes to
indicate the depth to which the contractor can exca-
vate to stay within the limits of suitable material, as
indicated by soil borings. This allows the borrow area
to drain readily and marks the limits of construction.
Set stakes to show the centerline location of the
principal spillway after foundation preparation has
reached the point at which the stakes will not be
disturbed. Locate the pipe where it will rest on a firm
foundation. Mark the stakes to show cuts from the top
of the stakes to the grade elevation of the pipe. With
additional stakes, mark the location of the riser, drain-
age gate, filter and drainage diaphragm or antiseep
collars, outlet structures, and other appurtenances.
Building the pond
Attention to the details of construction and adherence
to the drawings and specifications are as important as
adequate investigation and design. Careless and
shoddy construction can make an entirely safe and
adequate design worthless and cause failure of the
dam. Adherence to specifications and prescribed
construction methods becomes increasingly important
as the size of the structure and the failure hazards
increase. Good construction is important regardless of
size, and the cost is generally less in the long run than
it is for dams built carelessly.
Clearing and grubbing-Clear the foundation area
and excavated earth spillway site of trees and brush.
In some states this is required by statute. Cut trees and
brush as nearly flush with the ground as practicable
and remove them and any other debris from the dam
site. Should you or your contractor elect to uproot the
trees with a bulldozer, you must determine if the tree
roots extend into pervious material and if the resultant
holes will cause excessive seepage. If so, fill the holes
by placing suitable material in layers and compact
each layer by compacting or tamping.
All material cleared and grubbed from the pond site,
from the earth spillway and borrow areas, and from
the site of the dam itself should be disposed of. This
can be done by burning, burying under 2 feet of soil, or
burying in a disposal area, such as a sanitary landfill.
Minimal clearing conserves site character and mini-
mizes the difficulty and expense of reestablishing
vegetation. Confine clearing limits to the immediate
construction areas to avoid unnecessary disturbance.
53
Figure 30 A tree well preserves vegetation
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Removing all vegetation within the construction limits
is not always necessary. Selected groupings of desir-
able plants can be kept. Trees and shrubs can often
survive a 1- to 2-foot layer of graded fill over their root
systems or they can be root-pruned in excavated
areas. Tree wells and raised beds can also be used to
retain vegetation (fig. 30).
Clearing limits should be irregular to create a natural-
appearing edge and open area (fig. 31). Further transi-
tion with vegetated surroundings can be accomplished
by feathering clearing edges. Density and height of
vegetation can be increased progressively from the
water's edge to the undisturbed vegetation (fig. 32).
Feathering can be accomplished by selective clearing,
installation of new plants, or both.
Preparing the foundation-Preparing the founda-
tion includes treating the surface, excavating and
backfilling the cutoff trench, and excavating and
backfilling existing stream channels. If the foundation
has an adequate layer of impervious material at the
surface or if it must be blanketed by such a layer, you
can eliminate the cutoff trench. Remove sod, boulders,
and topsoil from the entire area over which the em-
bankment is to be placed. This operation is best per-
formed by using a tractor-pulled or self-propelled
wheeled scraper. The topsoil should be stockpiled
temporarily for later use on the site.
Fill all holes in the foundation area, both natural and
those resulting from grubbing operations, with suit-
able fill material from borrow areas. Use the same
method of placement and compaction as used to build
the dam. Where necessary use hand or power tampers
in areas not readily accessible to other compacting
equipment.
Figure 31
Irregular clearing around the pond helps
create a natural appearing edge
This
Not this • .
After filling the holes, thoroughly break the ground
surface and turn it to a depth of 6 inches. Roughly
level the surface with a disk harrow and then compact
it so that the surface materials of the foundation are
as well compacted as the subsequent layers of the fill. Dig
the cutoff trench to the depth, bottom width, and side
slopes shown on the drawings. Often the depths
shown on the drawings are only approximate; you
Figure 32 Feathering vegetation at the pond's edge makes a natural transition with existing vegetation
This Not this
Selective clearing
and/or plantings
Existing trees Existing trees
Minimum
clearing Clearing
limits limits
,, , Pond
Selective clearing and/or planting Lack of transition treatment
creates a natural appearance creates an unnatural edge
54
Agriculture Handbook 590
Ponds-Planning, Design, Construction
need to inspect the completed trench before backfill-
ing to be sure that it is excavated at least 12 inches
into impervious material throughout its entire length.
Material removed from the trench can be placed in the
downstream third of the dam and compacted in the
same manner as the earthfill if the material is free of
boulders, roots, organic matter, and other objection-
able material.
A dragline excavator and a tractor-pulled or self-
propelled wheeled scraper are the most satisfactory
equipment for excavating cutoff trenches. Before
backfilling operations are attempted, pump all free
water from the cutoff trench. Some material high in
clay content takes up more than twice its own weight
of water and becomes a soggy mass. Such clay pud-
dled in the cutoff of a dam may require many years to
become stable. Also, in drying it contracts and may
leave cracks that can produce a roof of the overlying
impervious earthfill section and provide passageways
for seepage through the dam.
Backfill the cutoff trench to the natural ground surface
with suitable fill material from designated borrow
areas. Place the backfill material in thin layers and
compact it by the same methods used to build the dam.
Deepen, slope back, and widen stream channels that
cross the embankment foundation. This is often neces-
sary to remove all stones, gravel, sand, sediment,
stumps, roots, organic matter, and any other objection-
able material that could interfere with proper bonding
of the earthfill with the foundation. Leave side slopes
of the excavated channels no steeper than 3:1 when
the channels cross the embankment centerline. If the
channels are parallel to the centerline, leave the side
slopes no steeper than 1:1. Backfill these channels as
recommended for the cutoff trench.
Installing the pipe spillway-Install the pipe, riser
(if applicable), filter and drainage diaphragm or anti-
seep collars, trash rack, and other mechanical compo-
nents of the dam to the lines and grades shown on the
drawings and staked at the site. To minimize the
danger of cracks or openings at the joints caused by
unequal settlement of the foundation, place all pipes
and other conduits on a firm foundation.
Install pipes and filter and drainage diaphragm or
antiseep collars and tamp the selected backfill mate-
rial around the entire structure before placing the
earthfill for the dam. The same procedure applies to
all other pipes or conduits.
Excavating the earth spillway-The completed
spillway excavation should conform as closely as
possible to the lines, grades, bottom width, and side
slopes shown on the drawings and staked at the site.
Leave the channel bottom transversely level to pre-
vent meandering and the resultant scour within the
channel during periods of low flow. If it becomes
necessary to fill low places or depressions in the
channel bottom caused by undercutting the estab-
lished grade, fill them to the established grade by
placing suitable material in 8-inch layers and compact-
ing each layer under the same moisture conditions
regardless of the placement in or under the embankment.
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Agriculture Handbook 590
Ponds-Planning, Design, Construction
Building the dam-Clear the dam and spillway area
of trees, brush, stumps, boulders, sod, and rubbish.
The sod and topsoil can be stockpiled and used later
to cover the dam and spillway (fig. 33). This will help
when vegetation is established. Get suitable fill mate-
rial from previously selected borrow areas and from
sites of planned excavation. The material should be
free of sod, roots, stones more than 6 inches in diam-
eter, and any material that could prevent the desired
degree of compaction. Do not use frozen material or
place fill material on frozen foundations.
Selected backfill material should be placed in the core
trench and around pipes and antiseep collars, when
used. The material should be compacted by hand
tamping or manually directed power tampers around
pipes. Begin placing fill material at the lowest point
and bring it up in horizontal layers, longitudinal to the
centerline of dam, approximately 6 inches thick. For
fill placement around risers, pipes and filter, and
drainage diaphragms, the horizontal layers should be
approximately 4 inches thick. Do not place fill in
standing water. The moisture content is adequate for
compaction when the material can be formed into a
firm ball that sticks together and remains intact when
the hand is vibrated violently and no free water ap-
pears. If the material can be formed into a firm ball
that sticks together, the moisture content is adequate
for compaction. Laboratory tests of the fill material
and field testing of the soil for moisture and compac-
tion may be necessary for large ponds or special
conditions.
If the material varies in texture and gradation, use the
more impervious (clay) material in the core trench,
center, and upstream parts of the dam. Construction
equipment can be used to compact earthfill in an
ordinary pond dam. Equipment that has rubber tires
can be routed so each layer is sufficiently covered by
tire tracks. For dams over 20 feet high, special equip-
ment, such as sheepsfoot rollers, should be used.
Figure 33 The sod and topsoil in a pond construction area can be stockpiled for later use
56
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Excavated ponds
Excavated ponds are the simplest to build in relatively
flat terrain. Because their capacity is obtained almost
solely by excavation, their practical size is limited.
They are best suited to locations where the demand
for water is small. Because excavated ponds can be
built to expose a minimum water surface area in
proportion to their volume, they are advantageous in
places where evaporation losses are high and water is
scarce. The ease with which they can be constructed,
their compactness, their relative safety from flood-
flow damage, and their low maintenance requirements
make them popular in many sections of the country.
Two kinds of excavated ponds are possible. One is fed
by surface runoff and the other is fed by ground water
aquifers, usually layers of sand and gravel. Some
ponds may be fed from both of these sources.
The general location of an excavated pond depends
largely on the purpose or purposes for which the
water is to be used and on other factors discussed
previously in this handbook. The specific location is
often influenced by topography. Excavated ponds fed
by surface runoff can be located in almost any kind of
topography. They are, however, most satisfactory and
most commonly used in areas of comparatively flat,
but well-drained terrain. A pond can be located in a
broad natural drainageway or to one side of a
drainageway if the runoff can be diverted into the
pond. The low point of a natural depression is often a
good location. After the pond is filled, excess runoff
escapes through regular drainageways.
Excavated ponds fed by ground water aquifers can be
located only in areas of flat or nearly flat topography.
If possible, they should be located where the perma-
nent water table is within a few feet of the surface.
Soils
If an excavated pond is to be fed by surface runoff,
enough impervious soil at the site is essential to avoid
excess seepage losses. The most desirable sites are
where fine-textured clay and silty clay extend well
below the proposed pond depth. Sites where sandy
clay extends to adequate depths generally are satisfac-
tory. Avoid sites where the soil is porous or is under-
lain by strata of coarse-textured sand or sand-gravel
mixtures unless you are prepared to bear the expense
of an artificial lining. Avoid soil underlain by limestone
containing crevices, sinks, or channels.
The performance of nearby ponds that are fed by
runoff and in a similar soil is a good indicator of the
suitability of a proposed site. Supplement such obser-
vations of existing ponds by boring enough test holes
at intervals over the proposed pond site to determine
accurately the kind of material there. You can get
some indication of permeability by filling the test holes
with water. The seepage indicates what to expect of a
pond excavated in the same kind of material.
If an excavated pond is to be fed from a water-bearing
sand or a sand-gravel layer, the layer must be at a
depth that can be reached practically and economi-
cally by the excavating equipment. This depth seldom
exceeds 20 feet. The water-bearing layer must be thick
enough and permeable enough to yield water at a rate
that satisfies the maximum expected demand for
water and overcomes evaporation losses.
Thoroughly investigate sites proposed for aquifer-fed
excavated ponds. Bore test holes at intervals over the
site to determine the existenceand physical character-
istics of the water-bearing material. The water level in
the test holes indicates the normal water level in the
completed pond. The vertical distance between this
level and the ground surface determines the volume of
overburden or excavation needed that does not con-
tribute to the usable pond capacity, but may increase
the construction cost considerably. From an economic
standpoint, this vertical distance between water level
and ground surface generally should not exceed 6 feet.
Check the rate at which the water rises in the test
holes. A rapid rate of rise indicates a high-yielding
aquifer. If water is removed from the pond at a rapid
rate, as for irrigation, the water can be expected to
return to its normal level within a short time after
removal has ceased. A slow rate of rise in the test
holes indicates a low-yielding aquifer and a slow rate
of recovery in the pond. Check the test hole during
drier seasons to avoid being misled by a high water
table that is only temporary.
57
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Spillway and inlet requirements
If you locate an excavated pond fed by surface runoff
on sloping terrain, you can use a part of the excavated
material for a small low dam around the lower end and
sides of the pond to increase its capacity. You need an
auxiliary spillway to pass excess storm runoff around
the small dam. Follow the procedures for planning the
spillway and provide protection against erosion as
discussed in the Excavating the earth spillway section.
Ponds excavated in areas of flat terrain generally
require constructed spillways. If surface runoff must
enter an excavated pond through a channel or ditch
rather than through a broad shallow drainageway, the
overfall from the ditch bottom to the bottom of the
pond can create a serious erosion problem unless the
ditch is protected. Scouring can occur in the side slope
of the pond and for a considerable distance upstream
in the ditch. The resulting sediment tends to reduce
the depth and capacity of the pond. Protect the slope
by placing one or more lengths of rigid pipe in the
ditch and extending them over the side slope of the
excavation. The extended part of the pipe or pipes can
be cantilevered or supported with timbers. The diam-
eter of the pipes depends on the peak rate of runoff
that can be expected from a 10-year frequency storm.
If you need more than one pipe inlet, the combined
capacity should equal or exceed the estimated peak
rate of runoff.
Pipe diameter 1/ Pond inflow 0
(in) (ft3/s)
15 0to6
18 6to9
21 9 to 13
24 13 to 18
30 18 to 30
36 30 to 46
42 46 to 67
48 67 to 92
54 92 to 122
60 122 to 157
l/ Based on a free outlet and a minimum pipe slope of 1 percent
with the water level 0.5 foot above the top of the pipe at the
upstream end.
In areas where a considerable amount of silt is carried
by the inflowing water, you should provide a desilting
area or filterstrip in the drainageway immediately
above the pond to remove the silt before it enters the
pond. This area or strip should be as wide as or some-
what wider than the pond and 100 feet or more long.
After you prepare a seedbed, fertilize, and seed the
area to an appropriate mix of grasses and forbs. As the
water flows through the vegetation, the silt settles out
and the water entering the pond is relatively silt free.
Planning the pond
Although excavated ponds can be built to almost any
shape desired, a rectangle is commonly used in rela-
tively flat terrain. The rectangular shape is popular
because it is simple to build and can be adapted to all
kinds of excavating equipment.
Rectangular ponds should not be constructed, how-
ever, where the resulting shape would be in sharp
contrast to surrounding topography and landscape
patterns. A pond can be excavated in a rectangular
form and the edge shaped later with a blade scraper to
create an irregular configuration (fig. 34).
The capacity of an excavated pond fed by surface
runoff is determined largely by the purpose or pur-
poses for which water is needed and by the amount of
inflow that can be expected in a given period. The
required capacity of an excavated pond fed by an
underground waterbearing layer is difficult to deter-
mine because the rate of inflow into the pond can
seldom be estimated accurately. For this reason, the
pond should be built so that it can be enlarged if the
original capacity proves inadequate.
Figure 34 Geometric excavation graded to create more
natural configuration
r'3 0 0
? Excavated area F-1 Final edge
58
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Selecting the dimensions-The dimensions selected
for an excavated pond depend on the required capac-
ity. Of the three dimensions of a pond, the most impor-
tant is depth. All excavated ponds should have a depth
equal to or greater than the minimum required for the
specific location. If an excavated pond is fed from
ground water, it should be deep enough to reach well
into the waterbearing material. The maximum depth is
generally determined by the kind of material exca-
vated and the type of equipment used.
The type and size of the excavating equipment can
limit the width of an excavated pond. For example, if a
dragline excavator is used, the length of the boom
usually determines the maximum width of excavation
that can be made with proper placement of the waste
material.
The minimum length of the pond is determined by the
required pond capacity.
To prevent sloughing, the side slopes of the pond are
generally no steeper than the natural angle of repose
of the material being excavated. This angle varies with
different soils, but for most ponds the side slopes are
1:1 or flatter (fig. 35).
If the pond is to be used for watering livestock, pro-
vide a ramp with a flat slope (4:1 or flatter) for access.
Regardless of the intended use of the water, these flat
slopes are necessary if certain types of excavating
equipment are used. Tractor-pulled wheeled scrapers
and bulldozers require a flat slope to move material
from the bottom of the excavation.
Estimating the volume-After you have selected the
dimensions and side slopes of the pond, estimate the
volume of excavation required. This estimate deter-
mines the cost of the pond and is a basis for inviting
bids and for making payment if the work is to be done
by a contractor.
The volume of excavation required can be estimated
with enough accuracy by using the prismoidal formula:
V= (A+4B+C
X ? [Eq.6]
6
where:
V = volume of excavation (yd3)
A = area of the excavation at the ground
surface (ft2)
B = area of the excavation at the mid-depth
(1/2 D) point (ft2)
C = area of the excavation at the bottom of the
pond (ft2)
D = average depth of the pond (ft2)
27 = factor converting cubic feet to cubic yards
Figure 35 Typical sections of an excavated pond
Total length 172 ft
A 6 ft
13 2, --- 136 ft------- 6 ft/
CN V ,-
110W Length 100 ft1014 48 ft--??
Longitudinal section
(not to scale)
Total width 88 ft -?I
A - - - - - - - - - -
-----
6 ft
fh B - 2J•64ft--- fif tiff Depth
2 ft
24 ft-?+Width 40 ft-?*24 ft
Cross section
(not to scale)
59
Agriculture Handbook 590
Ponds-Planning, Design, Construction
As an example, assume a pond with a depth, D, of 12
feet, a bottom width, W, of 40 feet, and a bottom
length, L, of 100 feet as shown in figure 35. The side
slope at the ramp end is 4:1, and the remaining slopes
are 2:1. The volume of excavation, V, is computed as
follows:
A = 88 x 172 =15,136
4B= 4(64 x 136) = 34,816
Then
C= 40x 100= 4,000
( A+ 4B+ C) = 53,952
V= 53,6 52 x 212 = 7 3,996 yd3
If the normal water level in the pond is at the ground
surface, the volume of water that can be stored in the
pond is 3,996 cubic yards times 0.00061963, or 2.48
acre-feet. To convert to gallons, 3,996 cubic yards
multiplied by 201.97 equals 807,072 gallons. The
sample procedure is used to compute the volume of
water that can be stored in the pond if the normal
water level is below the ground surface. The value
assigned to the depth D is the actual depth of the
water in the pond rather than depth of excavation.
Figure 36 Correct disposal of waste material
Waste material properly shaped,
graded, and vegetated blends This
into surrounding landscape.

Waste material poorly shaped,
unvegetated, and interrupting the
horizon line appears unnatural.
A summary of methods for estimating the volume of
an excavated pond is provided in appendix A. This
summary information is reprinted from NRCS (for-
merly SCS) Landscape Architecture Note No. 2, Land-
scape Design: Ponds, September 2, 1988.
Waste material-Plan the placement or disposal of
the material excavated from the pond in advance of
construction operations. Adequate placement prolongs
the useful life of the pond, improves its appearance,
and facilitates maintenance and establishment of
vegetation. The waste material can be stacked, spread,
or removed from the site as conditions, nature of the
material, and other circumstances warrant.
If you do not remove the waste material from the site,
place it so that its weight does not endanger the stabil-
ity of the side slopes and rainfall does not wash the
material back into the pond. If you stack the material,
place it with side slopes no steeper than the natural
angle of repose of the soil. Do not stack waste material
in a geometric mound, but shape and spread it to
blend with natural landforms in the area. Because
many excavated ponds are in flat terrain, the waste
material may be the most conspicuous feature in the
landscape. Avoid interrupting the existing horizon line
with the top of the waste mound (fig. 36).
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Agriculture Handbook 590
Ponds-Planning, Design, Construction
Waste material can also be located and designed to be
functional. It can screen undesirable views, buffer
noise and wind, or improve the site's suitability for
recreation (fig. 37). In shaping the material, the toe of
the fill must be at least 12 feet from the edge of the
pond. In the Great Plains you can place the waste
material on the windward side of the pond to serve as
a snow fence for collecting drifts in the pond. These
banks can also reduce evaporation losses by breaking
the force of prevailing winds across the pond.
Perhaps the most satisfactory method of handling
waste material is to remove it from the site. Complete
removal, however, is expensive and can seldom be
justified unless the material is needed nearby. Waste
material can sometimes be used advantageously for
filling nearby low areas in a field or in building farm
roads. If state or county highway maintenance crews
need such material, you may be able to have them
remove it.
Building the pond
Clear the pond area of all undesired vegetation. Mark
the outside limits of the proposed excavation with
stakes. On the stakes indicate the depth of cut from
the ground surface to the pond bottom.
Excavation and placement of the waste material are
the principal items of work in building this type pond.
The kind of excavating equipment used depends on
the climatic and physical conditions at the site and on
what equipment is available.
In low-rainfall areas where water is unlikely to accu-
mulate in the excavation, you can use almost any kind
of available equipment. Tractor-pulled wheeled scrap-
ers, dragline excavators, and track-type tractors
equipped with a bulldozer blade are generally used.
Bulldozers can only push the excavated material, not
carry it; if the length of push is long, using these ma-
chines is expensive.
In high-rainfall areas and in areas where the water
table is within the limits of excavation, a dragline
excavator is commonly used because it is the only
kind of equipment that operates satisfactorily in any
appreciable depth of water. For ponds fed by ground
water aquifers, a dragline is normally used to excavate
the basic pond.
Excavate and place the waste material as close as
possible to the lines and grades staked on the site. If
you use a dragline excavator, you generally need other
kinds of equipment to stack or spread the waste mate-
rial and shape the edge to an irregular configuration.
Bulldozers are most commonly used. Graders, either
tractor-pulled or self-propelled, can be used to good
advantage, particularly if the waste material is to be
shaped.
Figure 37 Waste material and plantings separate the pond from a major highway
61
Agriculture Handbook 590
Ponds-Planning, Design, Construction
Sealing the pond
Excessive seepage in ponds is generally because the
site is poor; that is, one where the soils in the im-
pounding area are too permeable to hold water. Select-
ing a poor site is often the result of inadequate site
investigations and could have been avoided. In some
places no satisfactory site is available, but the need for
water is great enough to justify using a site that is
somewhat less than satisfactory. In this case the
original pond design must include plans for reducing
seepage by sealing (fig. 38). In some places excessive
removal of the soil mantle during construction, usually
to provide material for the embankment, exposes
highly pervious material, such as sand, gravel, or rock
containing cracks, crevices, or channels. This can be
avoided by carefully selecting the source of embank-
ment material.
To prevent excessive seepage, reduce the permeability
of the soils to a point at which losses are insignificant
or at least tolerable. The method depends largely on
the proportions of coarse-grained sand and gravel and
of fine-grained clay and silt in the soil.
Compaction
Some pond areas can be made relatively impervious by
compaction alone if the material contains a wide range
of particle sizes (small gravel or coarse sand to fine
sand) and enough clay (10 percent or more) and silt to
effect a seal. This is the least expensive method of
those presented in this handbook. Its use, however, is
limited to these soil conditions as well as by the depth
of water to be impounded.
The procedure is simple. Clear the pond area of all
trees and other vegetation. Fill all stump holes, crev-
ices, and similar areas with impervious material.
Scarify the soil to a depth of 16 to 18 inches with a
disk, rototiller, pulverizer, or similar equipment. Re-
move all rocks and tree roots. Roll the loosened soil
under optimum moisture conditions in a dense, tight
layer with four to six passes of a sheepsfoot roller in
the same manner as for compacting earth embankments.
Make the compacted seal no less than 12 inches thick
where less than 10 feet of water is to be impounded.
Because seepage losses vary directly with the depth of
water impounded over an area, increase the thickness
of the compacted seal proportionately if the depth of
Figure 38 Disking in chemical additive to seal a pond
62
Agriculture Handbook 590
Ponds-Planning, Design, Construction
water impounded exceeds 10 feet or more. The thick-
ness of the compacted seal can be determined using
equation 7.
kx H
?Eq 7]
d ? v- k)
where:
d = thickness of compacted seal
k = coefficient of permeability of compacted
seal, which is assumed to be 0.003 fpd
unless testing is done
H = water depth
v = allowable specific discharge which is
assumed to be 0.028 fpd unless otherwise
specified
As an example, assume a pond with a depth, H, of 12
feet. No soil samples were taken for laboratory testing.
Therefore, use the assumed values for k and v. Calcu-
late the required minimum thickness of the compacted
seal. Using the preceding equation:
d= 0.003 fpdx 12 ft
0.028 fpd- 0.003 fpd
= 1.4 ft
If soil samples were taken and permeability tests were
performed on the material of the compacted seal at
the density it is to be placed, a thickness less than
what was calculated may be possible. Without know-
ing whether the soil underlying the compacted layer
will act as a filter for the compacted layer, the mini-
mum thickness should never be less than 12 inches.
Compact the soils in two or more layers not exceeding
9 inches uncompacted over the area. Remove and
stockpile the top layer or layers while the bottom layer
is being compacted.
Clay blankets
Pond areas containing high percentages of coarse-
grained soils, but lacking enough clay to prevent
excessive seepage, can be sealed by blanketing. Blan-
ket the entire area over which water is to be im-
pounded as well as the upstream slope of the embank-
ment. The blanket should consist of a well-graded
material containing at least 20 percent clay. The re-
quirements for good blanket material are about the
same as those described for earth embankments. You
can usually obtain material for the blanket from a
borrow area close enough to the pond to permit haul-
ing at a reasonable cost.
Thickness of the blanket depends on the depth of
water to be impounded. The minimum compacted
thickness is 12 inches for all depths of water under 10
feet. Increase this thickness by 2 inches for each foot
of water over 10 feet and above.
Construction is similar to that for earth embankments.
Remove all trees and other vegetation and fill all holes
and crevices before hauling earth material from the
borrow area to the pond site in tractor-pulled wheeled
scrapers or similar equipment. Spread the material
uniformly over the area in layers 6 to 8 inches thick.
Compact each layer thoroughly, under optimum mois-
ture conditions, by four to six passes of a sheepsfoot
roller before placing the next layer.
Protect clay blankets against cracking that results
from drying and against rupture caused by freezing
and thawing. Spread a cover of gravel 12 to 16 inches
thick over the blanket below the anticipated high
water level. Use rock riprap or other suitable material
to protect areas where the waterflow into the pond is
concentrated.
Bentonite
Adding bentonite is another method of reducing exces-
sive seepage in soils containing high percentages of
coarse-grained particles and not enough clay. Bento-
nite is a fine-textured colloidal clay. When wet it
absorbs several times its own weight of water and, at
complete saturation, swells as much as 8 to 20 times
its original volume. Mixed in the correct proportions
with well-graded coarse-grained material, thoroughly
compacted and then saturated, the particles of bento-
nite swell until they fill the pores to the point that the
mixture is nearly impervious to water. On drying,
however, bentonite returns to its original volume
leaving cracks. For this reason, sealing with bentonite
usually is not recommended for ponds in which the
water level is expected to fluctuate widely. A labora-
tory analysis of the pond area material to determine
the rate of application is essential.
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Agriculture Handbook 590
Ponds-Planning, Design, Construction
Before selecting this method of sealing a pond, locate
the nearest satisfactory source of bentonite and inves-
tigate the freight rates. If the source is far from the
pond site, the cost may prohibit the use of bentonite.
As with other methods, clear the pond area of all
vegetation. Fill all holes or crevices, and cover and
compact areas of exposed gravel with suitable fill
material.
The soil moisture level in the area to be treated is
important. Investigate it before applying bentonite.
The moisture level should be optimum for good com-
paction. If the area is too wet, postpone sealing until
moisture conditions are satisfactory. If it is too dry,
add water by sprinkling.
Spread the bentonite carefully and uniformly over the
area to be treated at the rate determined by the labora-
tory analysis. This rate usually is 1 to 3 pounds per
square foot of area. Thoroughly mix the bentonite with
the surface soil to a depth that will result in a 6-inch
compacted layer. This generally is an uncompacted
thickness of approximately 8 to 9 inches. A rototiller is
best for this operation, but a disk or similar equipment
can be used. Then compact the area with four to six
passes of a sheepsfoot roller.
If considerable time elapses between applying the
bentonite and filling the pond, protecting the treated
area against drying and cracking may be necessary. A
mulch of straw or hay pinned to the surface by the
final passes of the sheepsfoot roller gives this protec-
tion. Use rock riprap or other suitable material to
protect areas where water inflow into the treated area
is concentrated.
Chemical additives
Because of the structure or arrangement of the clay
particles, seepage is often excessive in fine-grained
clay soils. If these particles are arranged at random
with end-to-plate or end-to-end contacts, they form an
open, porous, or honeycomb structure; the soil is said
to be aggregated. Applying small amounts of certain
chemicals to these porous aggregates may result in
collapse of the open structure and rearrangement of
the clay particles. This dispersed structure reduces
soil permeability. The chemicals used are called dis-
persing agents.
The soils in the pond area should contain more than 50
percent fine-grained material (silt and clay) and at
least 15 percent clay for chemical treatment to be
effective. Chemical treatment is not effective in
coarse-grained soils.
Although many soluble salts are dispersing agents,
sodium polyphosphates and sodium chloride (com-
mon salt) are most commonly used. Of the sodium
polyphosphates, tetrasodium pyrophosphate and
sodium tripolyphosphate are most effective. Soda ash,
technical grade 99 to 100 percent sodium carbonate,
can also be used. Sodium polyphosphates generally
are applied at a rate of 0.05 to 0.10 pound per square
foot, and sodium chloride at a rate of 0.20 to 0.33 pound
per square foot. Soda ash is applied at a rate of 0.10 to
0.20 pound per square foot. A laboratory analysis of
the soil in the pond area is essential to determine
which dispersing agent will be most effective and to
determine the rate at which it should be applied.
Mix the dispersing agent with the surface soil and then
compact it to form a blanket. Thickness of the blanket
depends on the depth of water to be impounded. For
water less than 10 feet deep, the compacted blanket
should be at least 12 inches thick. For greater depths,
the thickness should be increased at the rate of 2 inches
per foot of water depth from 10 feet and above.
The soil moisture level in the area to be treated should
be near the optimum level for good compaction. If the
soil is too wet, postpone treatment. Polyphosphates re-
lease water from soil, and the material may become too
wet to handle. If the soil is too dry, add water by sprinkling.
Clear the area to be treated of all vegetation and trash.
Cover rock outcrops and other exposed areas of
highly permeable material with 2 to 3 feet of fine-
grained material. Thoroughly compact this material. In
cavernous limestone areas, the success or failure of
the seal may depend on the thickness and compaction
of this initial blanket.
Apply the dispersing agent uniformly over the pond
area at a rate determined by laboratory analysis. It can
be applied with a seeder, drill, fertilizer spreader, or by
hand broadcasting. The dispersant should be finely
granular, with at least 95 percent passing a No. 30
sieve and less than 5 percent passing a No. 100 sieve.
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Thoroughly mix the dispersing agent into each 6-inch
layer to be treated. You can use a disk, rototiller,
pulverizer, or similar equipment. Operating the mixing
equipment in two directions produces best results.
Thoroughly compact each chemically treated layer
with four to six passes of a sheepsfoot roller.
Protect the treated blanket against puncturing by
livestock. Cover the area near the high-water line with
a 12- to 18-inch blanket of gravel or other suitable
material to protect it against erosion. Use riprap or
other suitable material in areas where inflow into the
pond is concentrated.
Waterproof linings
Using waterproof linings is another method of reduc-
ing excessive seepage in both coarse-grained and fine-
grained soils. Polyethylene, vinyl, butyl-rubber mem-
branes, and asphalt-sealed fabric liners are gaining
wide acceptance as linings for ponds because they
virtually eliminate seepage if properly installed.
Thin films of these materials are structurally weak, but
if not broken or punctured they are almost completely
watertight. Black polyethylene films are less expensive
and have better aging properties than vinyl. Vinyl, on
the other hand, is more resistant to impact damage
and is readily seamed and patched with a solvent
cement. Polyethylene can be joined or patched with a
special cement.
All plastic membranes should have a cover of earth or
earth and gravel not less than 6 inches thick to protect
against punctures. Butyl-rubber membranes need not
be covered except in areas traveled by livestock. In
these areas a minimum 9-inch cover should be used on
all types of flexible membranes. The bottom 3 inches
of cover should be no coarser than silty sand.
Clear the pond area of all undesired vegetation. Fill all
holes and remove roots, sharp stones, or other objects
that might puncture the film. If the material is stony or
of very coarse texture, cover it with a cushion layer of
fine-textured material before placing the lining.
Some plants may penetrate both vinyl and polyethyl-
ene film. If nutgrass, johnsongrass, quackgrass, and
other plants having high penetration are present, the
subgrade, especially the side slopes, should be steril-
ized. Several good chemical sterilizers are available
commercially. Sterilization is not required for covered
butyl-rubber linings 20 to 30 mils thick.
Lay the linings in sections or strips, allowing a 6-inch
overlap for seaming. Vinyl and butyl-rubber linings
should be smooth, but slack. Polyethylene should have
up to 10 percent slack. Be extremely careful to avoid
punctures. Anchor the top of the lining by burying it in
a trench dug completely around the pond at or above
the normal water level. The anchor trench should be 8
to 10 inches deep and about 12 inches wide.
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Establishing vegetation
Trees, shrubs, grasses, and forbs should be planted
during or soon after construction. Their functions
include erosion control, screening, space definition,
climate control, and wildlife habitat. The vegetation
should be able to survive under prevailing conditions
with minimum maintenance. Native varieties are
preferred for new plantings.
In many areas the exposed surface of the dam, the
auxiliary spillway, and the borrow areas as well as
other disturbed surfaces can be protected from ero-
sion by establishing a vegetative community of appro-
priate species. Prepare a seedbed as soon after con-
struction as practicable. This is generally done by
disking or harrowing. Fertilize and seed with mixtures
of perennial grasses and forbs appropriate for local
soil and climatic conditions. If construction is com-
pleted when the soils are too dry for the seeds to
germinate, irrigate the soils to ensure prompt germina-
tion and continued growth. Mulching with a thin layer
of straw, fodder, old hay, asphalt, or one of several
commercially manufactured materials may be desir-
able. Mulching not only protects the newly prepared
seedbed, seeds, or small plants from rainfall damage,
but also conserves moisture and provides conditions
favorable for germination and growth.
Soil bioengineering systems should be employed to
establish woody vegetation where appropriate on the
shorelines of ponds. The systems best suited to these
conditions include live stakes, live fascines,
brushmattresses, live siltation, and reed clumps.
Additional information about these and other soil
bioengineering systems is in Part 650, Engineering
Field Handbook, chapters 16 and 18.
Trees and shrubs that remain or those planted along
the shoreline will be subject to flooding, wave action,
or a high water table. The ability to tolerate such
drastic changes varies greatly among species. Flood
tolerance and resistance to wave action depend on
root density and the ability to regenerate from ex-
posed roots.
A planting plan indicating the species and rate of
application of the vegetation can be helpful in achiev-
ing the desired results. For information on recom-
mended plants and grass mixtures, rates of fertiliza-
tion, and mulching procedures, contact the local
representatives of the Natural Resources Conservation
Service or the county agent.
Protecting the pond
Construction of the pond is not complete until you
have provided protection against erosion, wave action,
trampling by livestock, and any other source of dam-
age. Ponds without this protection may be short lived,
and the cost of maintenance is usually high.
Leave borrow pits in condition to be planted so that
the land can be used for grazing or some other pur-
pose. Grade and shape the banks or side slopes of
borrow pits to a slope that permits easy mowing,
preferably no steeper than 4:1, and allows the graded
area to blend with the landscape. It is often desirable
to establish vegetation to make the borrow area com-
patible with undisturbed surroundings.
Grade all areas or pits from which borrow material has
been obtained so they are well drained and do not
permit stagnant water to accumulate as breeding
places for mosquitoes.
Wave action
Several methods are available to protect the upstream
face of a dam against wave action. The choice of
method depends on whether the normal pool level
remains fairly constant or fluctuates. An irrigation
pond is an example of the latter. In these ponds, water
is withdrawn periodically during the growing season
and the water level may fluctuate from normal pool
level to near pond bottom one or more times each
year. The degree of protection required also influences
the choice of method.
Berms-If the water level in the pond is expected to
remain fairly constant, a berm 6 to 10 feet wide lo-
cated at normal pool level generally provides adequate
protection against wave action. The berm should have
a downward slope of about 6 to 12 inches toward the
pond. The slope above the berm should be protected
by vegetation.
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Ponds-Planning, Design, Construction
Booms-Log booms also break up wave action. A
boom consists of a single or double line of logs
chained or cabled together and anchored to each end
of the dam. Tie the logs end to end as close together as
practicable. Leave enough slack in the line to allow the
boom to adjust to fluctuating water levels. If you use
double rows of logs, frame them together to act as a
unit. For best results place the boom so that it floats
about 6 feet upstream from the face of the dam. If the
dam is built on a curve, you may need anchor posts on
the face of the dam as well as at the ends to keep the
boom from riding on the slope. Booms do not give as
much protection as some other methods described,
but they are inexpensive if timber is readily available.
They generally are satisfactory for small structures.
Riprap-Rock riprap is an effective method of control
if a high degree of protection is required or if the water
level fluctuates widely. Riprap should extend from the
top of the dam down the upstream face to a level at
least 3 feet below the lowest anticipated water level.
Riprap is dumped directly from trucks or other ve-
hicles or is placed by hand. Hand placing gives more
effective protection and requires less stone. Dumping
requires more stone, but less labor. The layer of stones
should be at least 12 inches thick and must be placed
on a bed of gravel or crushed stone at least 10 inches
thick. This bed keeps the waves from washing out the
underlying embankment material that supports the riprap.
If riprap is not continuous to the upstream toe, provide
a berm on the upstream face to support the layer of
riprap and to keep it from sliding downslope. If pos-
sible, use stones whose color is similar to that in the
immediate area. Allow grass and herbs to grow
through the riprap to blend with surrounding vegeta-
tion, but control woody vegetation.
Livestock
Complete fencing of areas on which embankment
ponds are built is recommended if livestock are grazed
or fed in adjacent fields. Fencing provides the protec-
tion needed to develop and maintain a good plant
cover on the dam, the auxiliary spillway, and in other
areas. It enhances clean drinking water and eliminates
damage or pollution by livestock. If you fence the
entire area around the pond and use the pond for
watering livestock, install a gravity-fed watering
trough just downstream from the dam and outside the
fenced area.
Fencing also enables you to establish an environment
beneficial to wildlife. The marshy vegetation needed
around ponds for satisfactory wildlife food and cover
does not tolerate much trampling or grazing.
Not all ponds used for watering livestock need to be
fenced. On some western and midwestern ranges, the
advantages derived from fencing are more than offset
by the increased cost and maintenance and the fact
that fewer animals can water at one time. A rancher
with many widely scattered ponds and extensive
holdings must have simple installations that require
minimum upkeep and inspection. Fencing critical
parts of livestock watering ponds, particularly the
earthfill and the auxiliary spillway, is usually advanta-
geous even if complete fencing is impractical.
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Agriculture Handbook 590
Ponds-Planning, Design, Construction
Operating and maintaining
the pond
A pond, no matter how well planned and built, must be
adequately maintained if its intended purposes are to
be realized throughout its expected life. Lack of opera-
tion and maintenance has caused severe damage to
many dams and spillways. Some structures have failed
completely. For these reasons you must be fully aware
of the need for adequate operation and maintenance,
and you should carry out all measures required.
Inspect your pond periodically. Be sure to examine it
after heavy rains to determine whether it is function-
ing properly or needs minor repairs. Repairing damage
immediately generally eliminates the need for more
costly repairs later. Damage may be small, but if ne-
glected it may increase until repair becomes impracti-
cal and the entire structure must be replaced.
Fill any rills on the side slopes of the dam and any
washes in the auxiliary spillway immediately with
suitable material and compact it thoroughly. Fertilize
as needed and reseed or resod these areas. If the
upstream face of the earthfill shows signs of serious
washing or sloughing because of wave action, install
protective devices, such as booms or riprap. If seepage
through or under the dam is evident, consult an engi-
neer at once so that you can take proper corrective
measures before serious damage occurs.
To maintain the protective plant cover on the dam and
on the auxiliary spillway, mow it frequently and fertil-
ize when needed. Mowing prevents the growth of
woody plants where undesirable and helps develop a
cover and root system more resistant to runoff. If the
plant cover is protected by fencing, keep the fences in
good repair.
Keep pipes, trash racks, outlet structures, valves, and
watering troughs free of trash at all times.
In some localities burrowing animals such as badgers,
gophers, beaver, and prairie dogs cause severe damage
to dams or spillways. If this damage is not repaired, it
may lead to failure of the dam. Using a submerged
inlet or locating the inlet in deeper water discourages
beavers from the pipe inlets. A heavy layer of sand or
gravel on the fill discourages burrowing to some
extent. Poultry netting can be used, but in time it rusts
out and needs to be replaced.
Keep the water in your pond as clean and unpolluted
as possible. Do not permit unnecessary trampling by
livestock, particularly hogs. If fencing is not practical,
pave the approaches to the pond with small rocks or
gravel. Divert drainage from barn lots, feeding yards,
bedding grounds, or any other source of contamina-
tion away from the pond. Clean water is especially
important in ponds used for wildlife, recreation, and
water supply.
In areas where surface water encourages mosquito
breeding, stock the pond with topfeeding fish. Gambu-
sia minnows are particularly effective in controlling
mosquitoes. In malaria areas, do not keep any aquatic
growth or shoreline vegetation and take special pre-
cautions in planning, building, and operating and
maintaining the pond. Most states in malaria areas
have health regulations covering these precautions.
These regulations should be followed.
In some areas, algae and other forms of plant life may
become objectionable. They can cause disagreeable
tastes or odors, encourage bacterial development, and
produce an unsightly appearance.
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Agriculture Handbook 590
Ponds-Planning, Design, Construction
Pond safety
Ponds, like any body of water, attract people so that
there is always a chance of injury or drowning. You
may be planning to build a pond for watering live-
stock, irrigation, or any of the other purposes dis-
cussed in this handbook. However, your family and
friends may picnic beside the pond or use it for fish-
ing, swimming, boating, or ice skating, and you can
never tell what a small child passing by may do.
Your pond can become a source of pleasure as well as
profit, but only if it is safe. You can take some of the
following steps to prevent injuries or drownings and to
protect yourself financially.
Before construction
Almost all states have laws on impounding water and
on the design, construction, and operation and mainte-
nance of ponds. In many states small farm ponds are
exempt from any such laws. You should become
familiar with those that apply in your state and be sure
that you and your engineer comply with them.
Find out what your community or state laws are
regarding your liability in case of injury or death
resulting from use of your pond, whether you autho-
rize such use or not. This is particularly important if
you intend to open your pond to the public and charge
a fee for its use. You may find that you need to protect
yourself with insurance.
You should decide how the water is going to be used
so that you can plan the needed safety measures
before construction starts. For example, if the water is
to be used for swimming, guards over conduits are
required. You may wish to provide for beaches and
diving facilities; the latter require a minimum depth of
about 10 feet of water.
During construction
Your contractor should take other safety measures
during pond construction. Remove all undesirable
trees, stumps, and brush and all rubbish, wire, junk
machinery, and fences that might be hazardous to
boating and swimming. Eliminate sudden dropoffs and
deep holes.
After completion
Mark safe swimming areas and place warning signs at
all danger points. Place lifesaving devices, such as ring
buoys, ropes, planks, or long poles, at swimming areas
to facilitate rescue operations should the need arise.
Place long planks or ladders at ice skating areas for
the same reason.
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Agriculture Handbook 590 Ponds-Planning, Design, Construction
References
U.S. Department of Agriculture, Soil Conservation
Service. 1984. Engineering Field Manual.
Washington, DC.
U.S. Department of the Army, Corps of Engineers.
Technical Report E-79-2, Root tolerance of
plants: A state-of-the-art review.
U.S. Department of Agriculture, Soil Conservation
Service. 1988. Landscape Design: Ponds, Land-
scape Architecture Note 2. Washington, DC.
Van Dersal, William R. 1938. Native Woody Plants of
the United States. Miscellaneous Publication 303.
U.S. Department of Agriculture. Washington, DC.
70
Glossary
abutment A portion of a valley cross section higher in elevation than the valley floor.
The slope above the valley floor.
antiseep collar A constructed barrier installed perpendicular to a pipe or conduit and
usually made of the same material as the pipe or conduit. Its purpose is to
intercept the flow of seepage along the pipe or conduit and to make the
seepage path longer.
appurtenance Interrelated elements or components of a designed system, or structure.
auxiliary spillway The spillway designed to convey excess water through, over, or around a
dam.
backslope The downstream slope of an embankment.
bench mark Point of known elevation for a survey. May be in relation to National Geo-
detic Vertical Datum (NGVD) or assumed for a given project.
berm A strip of earth, usually level, in a dam cross section. It may be located in
either the upstream side slope, downstream side slope, or both.
boom A floating barrier extending across a reservoir area, just upstream from the
dam, to protect the side slope from erosion.
borrow area An area from which earthfill materials can be taken to construct the dam.
bottom width A flat, level cross section element normally in an open channel, spillway, or
trench.
coefficient The rate of flow of a fluid through a unit cross section of a porous mass
of permeability under a unit hydraulic gradient.
compaction The process by which the soil grains are rearranged to decrease void space
and bring them into closer contact with one another, thereby increasing the
weight of solid material per cubic foot.
conduit (pipe) Any channel intended for the conveyance of water, whether open or closed.
control section A part of an open channel spillway where accelerated flow passes through
critical depth.
core trench The trench in the foundation material under an earth embankment or dam
(excavation) in which special material is placed to reduce seepage.
of a trench)
critical depth Depth of flow in a channel at which specific energy is a minimum for a
given discharge.
cross section A section formed by a plane cutting an area, usually at right angles to an axis.
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Agriculture Handbook 590
Ponds-Planning, Design, Construction
dam (earth dam) A constructed barrier, together with any associated spillways and appurte-
nant works, across a watercourse or natural drainage area, which perma-
nently impounds and stores water, traps sediment, and/or controls flood
water.
design elevation The height above a defined datum describing the required elevation of pool
that will provide the required temporary storage.
diaphragm See Antiseep collar.
drain An appurtenance installed in the dam and/or its foundation to safely collect
and discharge seepage water.
drawings A graphical representation of the planned details of the work of improvements.
drop inlet A vertical entrance joined to a barrel section of a principal spillway system.
earthfill Soil, sand, gravel, or rock construction materials used to build a dam and its
components.
effective The difference in elevation in feet between the lowest auxiliary spillway
fill height crest and the lowest point in the original cross section on the centerline of
the dam. If there is no auxiliary spillway, the top of the dam becomes the
upper limit.
embankment A structure of earth, gravel, or similar material raised to form a dam.
excavated pond A reservoir constructed mainly by excavation in flat terrain. A relatively
short embankment section on the downstream watercourse side may be
necessary for desired storage amount.
exit channel The portion downstream from the control section that conducts the flow to
(of an open a point where it may be released without jeopardizing the dam.
channel spillway)
fill height The difference in elevation between the existing ground line and the pro-
posed top of dam elevation, including allowance for settlement.
filter and drainage A soil piping and water seepage control device installed perpendicular to a
diaphragm pipe or conduit, consisting of a single, or multizones of, aggregate. Its
purpose is to intercept the water flow along pipes or conduits and prevent
the movement of soil particles that makeup the embankment.
flow depth The depth of water in the auxiliary spillway or any other channel.
foundation The surface upon which a dam is constructed.
freeboard The difference in elevation between the minimum settled elevation of the
top of dam and the highest elevation of expected depth of flow through the
auxiliary spillway.
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Agriculture Handbook 590
Ponds-Planning, Design, Construction
hooded or A fabricated assembly attached to the principal spillway pipe to improve
canopy inlet the hydraulic efficiency of the overall pipe system.
inlet section The portion upstream from the control section.
(of an open
channel spillway)
mulch A natural or artificial layer of plant residue or other material, such as grain
straw or paper, on the soil surface.
outlet channel A section of open channel downstream from all works of improvement.
outlet section The downstream portion of an open channel or of a principal spillway.
peak discharge The maximum flow rate at which runoff from a drainage area discharges
past a specific point.
pond A still body of water of limited size either naturally or artificially confined
and usually smaller than a lake.
pool area The location for storing water upstream from the dam.
principal spillway The lowest ungated spillway designed to convey water from the reservoir at
predetermined release rates.
profile A representation of an object or structure seen from the side along its
length.
propped outlet A structural support to protect the outlet section of a pipe principal spillway.
riprap A loose assemblage of broken stones commonly placed on the earth surface
to protect it from the erosive forces of moving water or wave action.
riser The vertical portion of a drop inlet.
sealing The process used to close openings in soil materials and prevent seepage of
water.
sediment Solid material, both mineral and organic, that is being transported in sus-
pension, or has been moved from its site of origin by water, air, gravity, or
ice and has come to rest on the Earth's surface either above or below the
principal spillway crest.
settlement Movement of an embankment or structure during the application of loads.
side slope (ratio) The ratio of horizontal to vertical distance measured along the slope, either
on an open channel bank or on the face of an embankment, usually ex-
pressed in "n":1; e.g., 2:1 (meaning two units horizontal to one unit vertical).
site investigation Site visit to evaluate physical features of a proposed project or watershed
including soils data and characteristics of the watershed.
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Agriculture Handbook 590
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specifications Detailed statements prescribing standards, materials, dimensions, and
workmanship for works of improvement.
specific discharge The theorical flow rate through the full flow cross sectional area of a po-
rous media.
spillway An open or closed channel, conduit or drop structure used to convey water
from a reservoir. It may contain gates, either manually or automatically
controlled, to regulate the discharge of water.
stage The elevation of a water surface above its minimum plane or datum of
reference.
storage volume The total volume available from the bottom of the reservoir to the top of
dam.
temporary storage The volume from the crest of the principal spillway to the top of dam.
top width The horizontal dimension (planned or existing) across the top of dam,
perpendicular to the centerline.
valley floor Part of a valley cross section that is level or gently sloping.
vegetative The amount of hindrance to flow caused by the type, density, and height
retardance of vegetation.
visual focus An element in the landscape upon which the eyes automatically focus
because of the element's size, form, color, or texture contrast with its
surroundings.
74
Appendix A Estimating the Volume of an
Excavated Pond
The volume of a pond can be estimated by using the Rectangle:
prismoidal formula:
(A+4B+C)
V= X D
6 27
A
B
A
B D
C
?- C --?I
V = volume of excavation (yd3)
A = area of excavation at ground level (ft2)
B = area of excavation at the middle depth of
the pond (ft2)
C = area of excavation at the bottom of the
pond (ft2)
D = average depth of the pond in (ft)
27= factor converting cubic feet to cubic yards
Note: When using meters for area and depth, 27 is not
needed. The formula would then be:
(A+4B+C)
V= xD
6
where:
V = volume of excavation (m3)
This formula can be used for ponds of any shape. The
area of excavation can be determined either by
planimetering the shape on the plans or by using
geometric formulas for areas. The following formulas
give the area of some common shapes.
?w
Circle:
0
Quadrant:
I+- r-?1
Parabola:
M h
14-S-01
Ellipse:
Rectangle A = wl
Circle A = icr2 or 3.14 r2
)
Quadrant A = 4 `l r2 or 0.7854r'
Parabola A = 0.67 sh
w
Ellipse A = 4 w1 or 0.7854 wl
1
75
Agriculture Handbook 590 Ponds - Planning, Design, Construction
Example A-1 Determing the volume of an elliptical pond
As an example, determine the volume of an elliptical
pond with a major axis (b of 160 ft, a minor axis (1)
of 90 ft at the surface, a depth (D) of 8 ft, and 2:1 side
slopes. Use the prismoidal formula:
(A+4B+C)
V= X D
6 27
160 in.
D'I
A B D
CI_ C?
Step 1: Calculate the area of the surface (A) using the
formula,
Area = (TO 4 wl for an ellipse
A = 144 (90 x 160)
A =11, 304 ft2
Step 2: Determine the dimensions of the bottom (C).
Since the side slopes are 2:1 and depth is 8 feet, the
bottom will be 16 feet narrower than the surface. The
bottom dimensions would then be 58 feet (w) by 128
feet (4.
Step 3: Calculate the area of the bottom (C) using
C = 3.44 (58 x 128)
C = 5,828 ft2
Step 4: Determine the dimensions of the middle
depth (B). Since the middle depth lies equally be-
tween the surface and the bottom, the dimensions can
be determined by adding the surface and bottom
dimensions together and dividing by 2.
160+128
2 =144 (major axis)
90 + 58 = 74 (minor axis)
2
Step 5: Calculate the area of the middle depth (B)
using Area = (pi) wl.
B= 3'44 (74x144)
B = 8,365 ft2
160 ft? 0 ft
144 ft ?4 f
1\ ? 1\ 8 ft
2 128 ft-? 2 ?58 fti
Step 6: Determine the volume in cubic yards.
V _ 111, 304 + (4 x 8,365) + 5,828 1 x 8
6 27
V _ 5Q 592 x 8
6 27
V = 2,498 or approx. 2,500 yd'
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Agriculture Handbook 590
Ponds - Planning, Design, Construction
Example A-2 Determining area of the surface, the middle depth, and bottom
The area of the surface, the middle depth, and bottom
can also be determined by using a planimeter. In this
example, the pond was drawn at a 1 inch = 40 feet
scale and has a depth of 8 feet.
Step 1: Measure the surface area (A) using a planime-
ter. Convert the measurement from square inches into
square feet. (A factor of 1,600 is used to convert square
inches into square feet for a scale of 1 inch = 40 feet.)
A =10.0 1n 2 x 1, 600 =16, 16,000 ft2
Step 2: Measure the middle depth (B) area and con-
vert to square feet.
B = 7.7 in 2 x 1, 600 =12, 12,320 ft2
Step 3: Measure the bottom (C) and convert to square
feet.
C = 5.5 in 2 x 1, 600 = 8, 800 ft2
Step 4: Use the prismoidal formula to estimate vol-
ume of excavation in cubic yards.
(A+ 4 B+ C)
8
V= x
6 27
V = [16, 000 + (4 x 12, 320) + 8, 800] x 8
6 27
V= 74,080 x 8
6 27
V = 3,658
yd3
II I?
/? II
A
BC II
?? 11
Scale: 1 inch = 40 feet
77
Appendix B Flood-Tolerant Native Trees and
Shrubs
Flooding creates several conditions that are unfavor-
able to most woody species. The most critical condi-
tion appears to be the depletion of soil oxygen that is
critical to plants. The lack of oxygen favors anaerobic
bacteria, which can lead to the development of toxic
organic and inorganic byproducts. A plant's ability to
survive flooding is dependent on many factors; among
them are flood depth, flood duration, flood timing, plant
age and size, wave action, and substrata composition.
The plant lists in tables B-1 through B-4 were taken
from the Corps of Engineers Technical Report E-79-2,
Flood Tolerance of Plants: A State-of-the-Art Review.
The ratings used are intended only to be a relative
classification. Tolerance will vary with local condi-
tions. The plants are divided into four groups: very
tolerant, tolerant, somewhat tolerant, and intolerant.
Each plant was also given a range coinciding with the
plant growth regions, figure B-1, developed from
USDA Miscellaneous Publication 303, Native Woody
Plants of the United States, by William R. Van Dersal.
79
Agriculture Handbook 590
Ponds - Planning, Design, Construction
Figure B-1 Plant growth regions
1. North Pacific Coast
2. Willamette Valley-Puget Soun(
3. Central California Valleys
4.Cascade-Sierra Nevada
C
5. Southern California
6. Columbia River Valley
0 7. Palouse-Bitterroot Valley
Q 8. Snake River Plain-Utah Valley
9. Great Basin-Intermontane
=10. Southwestern Desert
=11.Southern Plateau
M12.Northern Rocky Mountains
=13.Central Rocky Mountains
=14.Southern Rocky Mountains
015. Northern Great Plains
016.Central Great Plains
017.Southern Plains
18. Northern Black Soils
019. Central Black Soils
20. Southern Black Soils
D 21. Northern Prairies
22. Central Prairies
23. Western Great Lakes
24. Central Great Lakes
25. Ozark-Ohio-Tennessee River Valley
26. Northern Great Lakes-St. Lawrence
27. Appalachian
28. Piedmont
29. Upper Coastal Plain
30. Swampy Coastal Plain
= 31. South-Central Florida
=32. Subtropical Florida
80
Agriculture Handbook 590
Ponds - Planning, Design, Construction
Table B-1 Flood tolerance of very tolerant native plants
[These plants are able to survive deep, prolonged flooding for more than 1 year.]
Scientific name
Common name Range
Carya aquatica
C. illinoensis
Cephalanthus occidentalis
Corn us stolonifera
Forestiera acuminata
Fraxinus pennsylvanica
Gleditsia aquatica
Illex decidua
Nyssa aquatica
Planera aquatica
Quercus lyrata
Salix exigua
S. hookeriana
S. lasiandra
S. nigra
Taxodium distichum
Water hickory
Pecan
Buttonbush
Redosier dogwood
Swamp privet
Green ash
Waterlocust
Deciduous holly
Water tupelo
Water elm
Overcup oak
Narrow leaf willow
Hooker willow
Pacific willow
Black willow
Baldcypress
20, 25, 28, 29, 30
16, 20, 22, 25, 29, 30
3-5,11,16,17,19-30
4,7-9,11-15,18,21 -28
20, 22, 25, 29, 30
15, 18, 20-30
20, 25, 28-30
16, 17, 20, 25, 28-30
25, 29, 30
20, 25, 29, 30
20, 22, 25, 28-30
4-16
1
1-5,11,13,14
16,17,19-30
17, 20, 25, 28-32
81
Agriculture Handbook 590
Ponds - Planning, Design, Construction
Table B-2 Flood tolerance of tolerant native plants
[These plants are able to survive deep flooding for one growing season, with significant
mortality occurring if flooding is repeated the following year.]
Scientific name
Common name Range
Acer negundo Boxelder 17-30
A. rubrum Red maple 19-30
A. saccharinum Silver maple 18-30
Alnus glutinosa Black alder 26-27
Amorpha fruticosa False indigo 5,10,11,15-29
Betula nigra River birch 20, 22, 23, 25-29
Celtis occidentalis Hackberry 15,16,18,20-30
Diospyros virginiana Persimmon 20, 22, 25, 27-31
Kalmia polifolia Bog laurel 4, 12, 23, 24, 26, 27
Ledum groenlandicum Labrador tea 4, 12, 23, 24, 26, 27
Liquidambar styraciflua Sweetgum 20, 22, 25, 27-30
Nyssa sylvatica Blackgum 20, 22, 24-30
Pinus contorta Lodgepole pine 2,4,10,12-15
Platanus occidentalis Sycamore 16, 20-22, 24-30
Populus trichocarpa Black cottonwood 1-8,12,13
Quercus lyrata Overcup oak 20, 22, 25, 28-30
Q. palustris Pin oak 21-25, 27, 29
Sambucus callicarpa Pacific red elder 1,2,4
Spirea douglasii Hardback 1-4
Tamarixgallica French tamarisk 3, 4, 9-11, 13, 16, 19, 22, 25, 29, 30
Thuja plicata Western redcedar 1, 2, 4, 6, 7, 12
Ulmus americana American elm 15, 16, 18-23, 25-30
Vaccinium uliginosum Blueberry 1, 4, 12-14, 23, 24, 26, 27
82
Agriculture Handbook 590
Ponds - Planning, Design, Construction
Table B-3 Flood tolerance of somewhat tolerant native plants
[These plants are able to survive flooding or saturated soils for 30 consecutive days during the growing season.]
Scientific name
Common name Range
Alnus rugosa Hazel alder 20,22-29
Carpinus caroliniana Ironwood 20-30
Celtis laevigata Sugarberry 11, 16, 17, 20, 22, 25, 29, 30
Cornus nuttallii Pacific dogwood 1-5
Crataegus mollis Downy hawthorn
Fraxinum americana White ash 20, 22-25, 27-30
Gleditsia triacanthos Honeylocust 16, 20, 22-27, 29, 30
Ilex opaca American holly 20, 25, 27-30
Juglans nigra Black walnut 18-30
Juniperus virginiana Eastern redcedar 18,20-29
Malus spp. Apple
Morus rubra Red mulberry 16-25, 27-30
Ostrya virginiana Eastern hophornbeam 15, 18, 20-25, 27-30
Picea stichensis Sitka spruce 1
Pinus echinata Shortleaf pine 20, 25, 27-30
P. ponderosa Ponderosa pine 4
Populusgrandidentata Bigtooth aspen 21-23, 25-28
Quercus alba White oak 20,22-30
Q. bicolor Swamp white oak 21-28
Q. imbricaria Shingle oak 22-25, 27, 28
Q. macrocarpa Bur oak 15,16,18-30
Q. nigra Water oak 17, 20, 25, 28-30
Q. phellos Willow oak 20, 25, 27-30
Q. rubra Northern red oak 21 -27
Rhusglabra Smooth sumac 6-9,11,14,15,17-31
Tilia americana American basswood 20-27
Tsuga heterophylla Western hemlock 1 , 2, 4, 6, 12
Ulm us alata Winged elm 17, 20, 25, 28-30
U. rubra Red elm 25, 27, 29
Viburnum prunifolium Blackhaw 20, 22-25, 27-30
83
Agriculture Handbook 590
Ponds - Planning, Design, Construction
Table B-4 Flood tolerance of intolerant native plants
[These plants are unable to survive more than a few days of flooding during the growing
season without significant mortality.]
Scientific name
Common name Range
Acermacrophyllum Bigleaf maple 1-5
A. saccharum Sugar maple 15,18,21-29
Alnus rubra Red alder 1 , 2, 5, 6
A. sinuata Sitka alder 2, 4, 6, 7, 12
Betula lutea Yellow birch 21-28
B. papyrifera Paper birch 12, 13, 15, 18, 21-24, 26, 27
B. populifolia White birch 24, 26-28
Buxus sempervirens Boxwood
Carya cordiformis Bitternut hickory 20,22-30
C. laciniosa Shellbark hickory 22, 24, 25, 27, 28, 29
C. ovata Shagbark hickory 21-30
C. tomentosa Mockernut hickory 20, 22, 24, 25, 27-30
Cercis canadensis Eastern redbud 22-25, 27-30
Coryus Florida Flowering dogwood 20, 22-25, 27-30
Corylus avellana Filbert
C. rostrata Hazel 15, 18, 21-29
Cotoneaster spp. Cotoneaster
Fagusgrandifolia American beech 20,22-30
Gymnocladus dioica Kentucky coffeetree 19, 21-25, 27
Ilex aquifolium Holly
Philadelphus gordonianus Mock orange 4,6-8,12
Picea abies Norway spruce
P. pungens Colorado spruce 9, 12, 13, 14
P. rubens Red spruce 27
Pinus strobus Eastern white pine 21-24,27
P. taeda Loblolly pine 19, 20, 22, 25, 28-30
Populus tremuloides Quaking aspen 1, 2, 4, 6-9, 11, 15, 18, 21-27
Prunus americana Wild plum 12-25, 27-30
P. emarginata Bitter cherry 1, 2, 4, 6, 8-14
P. laurocerasus Cherry-laurel
P. serotina Black cherry 11,18-30
Psuedotsuga menziesii Douglas fir
Pyrus rivularis Wild apple 1, 2, 4
Q. marilandica Blackjack oak 16,19, 20, 22, 24, 25, 27-30
Q. muehlenbergii Chinquapin oak 11, 16, 20-30
Q. shumardii Texas oak 16, 20, 22, 24, 25, 27-29
Q. stellata Post oak 19, 20, 22, 25, 27-30
Q. velutina Black oak 20,22-30
Rhamnus purshinana Cascara 1-4,6,7, 9, 11, 12
Rubus procerus Blackberry
84
Agriculture Handbook 590
Ponds - Planning, Design, Construction
Table B-4
Scientific name
Common name Range
Sassafras albidum
Sorbus aucuparia
Symphoricarpos occidentalis
Syringa vulgans
Thuja occidentalis
Tsuga canadensis
Flood tolerance of intolerant native plants-Continued.
[These plants are unable to survive more than a few days of flooding during the growing
season without significant mortality.]
Sassafras 20,22-30
Rowan tree 21, 22, 27
Snowberry 15, 18, 21-24
Lilac
American arborvitae 22-24, 26, 27
Eastern hemlock 22-25, 27, 28
85
Page 1 of 1
Nikki Thomson
From: Lastinger, James C SAW [[e-mail]
Sent: Tuesday, October 07, 2008 10:02 AM
To: Nikki Thomson
Subject: FW: Franklin County Pond
Nikki,
I am forwarding this message to you from Shari Bryant. This is a list of her concerns. They seem to be pretty much
in line with my concerns as well. That request for information should be headed your way soon.
thanks,
James Lastinger
919-554-4884 ext 32
From: Shari Bryant [mailto:[e-mail]]
Sent: Friday, October 03, 2008 5:09 PM
To: Lastinger, James C SAW
Subject: Franklin County Pond
James,
I have a copy of the DWQ application and after reviewing it I have the following questions.
1. Were off line impoundments evaluated? If so, why were these not considered? If not, why were these not
evaluated?
2. It appears there will be a minimum release, but how will the minimum release be determined? If the minimum
release has been determined, what is the proposed minimum release?
3. The applicant indicates that the mitigation is to preserve and enhance the stream channel, wetlands, and
riparian buffers downstream of the pond. What is proposed to be enhanced? Will buffers and wetlands be
replanted, instream aquatic habitat improved?
4. Also, I have polled some of our staff and done a bit of research. Generally speaking, the minimum size for a
largemouth bass pond is 1 acre. However, managing bass in a 1 acre pond can be challenging. Quality
largemouth bass can be established in ponds around 5 acres; some 4 acre ponds have produced trophy size
bass with proper management. So, I guess I too would question the need for a 10 acre pond for largemouth
bass
I'm sorry I couldn't attend the site visit, but before drafting my comments I thought I would see if any of this
information or answers to these questions became available during or after the site visit.
I'll be out of the office most of next week, but if we need to discuss anything, I plan to be back on Oct. 13.
Thanks and have a good weekend.
Shari L. Bryant
N.C. Wildlife Resources Commission
P.O. Box 129
Sedalia, NC 27342-0129
336.449.7625
[e-mail]
10/23/2008
From: Russell Wright [mailto:[e-mail]]
Sent: Wed 10/1/2008 12:48 PM
To: Kevin Martin
Cc: Michael Maceina
Subject: RE: Minimum Pond size for Largemouth Bass Management
Kevin,
For trophy management I agree with you entirely there is no doubt that
you need a pond at least 8-10 acres. That gives you the ability to
maintain a significant shad population and a large enough population of
adult bass to produce the extraordinary few percent that are the
trophies. My only suggestion would be to not remove all the big
bluegill. Those large individuals will produce spawns late in the year.
You can certainly take out what you want without major issues but I
just wouldn't take out all the big ones.
Rusty
Russell A. Wright
Extension Specialist
Associate Professor of Fisheries
Department of Fisheries and Allied Aquacultures
Auburn University
36849
email [e-mail]
Tel. [phone]
FAX [phone]
Here is the local guy
From: Mitchell [mailto:[e-mail]]
Sent: Thu 9/25/2008 10:14 AM
To: Kevin Martin
Subject: RE: minimum size for largemouth bass pond
hfti)://www.aipms.or-q/iar)m/vol34/v34p48.i)d
f
http://www.ces.ncsu.edu/nreos/
http://srac.tamu.edu/tmppdfs/450146-200fs.pdf?CFID=450146&CFTOKEN=391 c46f1 a8bO5946-
4D8C4E66-7E93-35CB-8F28FOAB359E0818&jsessionid=8e30c6acce3542673316
Kevin,
Here are a couple of places with some valid information. The first one is definitely the
most pertinent to your situation. Basically it's developing a relationship between small, shallow
ponds with limited food and reproductive areas due to increased plant growth and lack of
structure.
Most biologists across the U.S. would tell you that a minimum size of 8-10 acres is required to
effectively grow trophy fish. As you know, carrying capacity of ponds is limited, so the greater
volume of water, the higher the potential yield. Trophy fish can be grown in smaller ponds, but it
is more difficult due to the limited food supply and lack of surface area. I hope this information
helps.
Thanks,
Mitchell Morton
Manager, Fisheries Division
Foster Lake & Pond Management
www.fosterlake.com
919-772-8548
Fisheries and Allied Aquacultures: Auburn University
Faculty
Affiliate Professors
Administration & Professional
Staff
Superintendents
Research Associates &
Assistants
Adjunct Professors
Emeriti/Retired
Collaborating Auburn University
Faculty
Page 1 of 3
Contact Information
Russell A. Wright
Extension Specialist
Associate Professor
(334)-844-9311
[e-mail]
Field of Specialization
Fisheries Biology & Ecology
Professional Affiliations Special Honors & Awards I Research Publications I
Title Journal Year
First-year growth and recruitment of coastal
largemouth bass ( Micropterus salmoides
11 Canadian Journal of Fisheries 2006
spatial patterns unresolved
by critical periods and Aquatic Science
along a salinity gradient
Daphnia lu . oltzi in the Mobile River Drainage,
USA: Invasion of a Habitat That Experiences Journal of Freshwater Ecology 2006
Salinity
Movement Patterns of Coastal Largemouth
Bass in the Mobile-Tensaw River Delta,
Alabama: A Multi-app-roach Stud Annual Conference of the
Southeastern Association of
Fish and Wildlife Agencies
2005
Using Grass Carp to Control Weeds in Alabama 2004
Ponds revised
he Effects of Age-0 Body Size on the

Predictive Ability of
a Largemouth Bass Transactions of the American
2004
,
_. _
Bioener etics Model Fisheries Society
Evaluating the Potential for Predatory Control

of Gizzard Shad by Largemouth Bass in Small Transactions of the American
2003
-- -
Impoundments: A Bioenergetics Approach Fisheries Society
Energetic Adaptations along a Broad Latitudinal
Gradient: Implications for Widely Distributed BioScience 2003
Assemblages
2002 Alabama freshwater anglers survey Southeastern Association of

Fish and Wildlife Agencies
2003
Individual growth and foraging responses of

age-0 largemouth bass to mixed prey Environmental Biology of
2003
assemblages during winter Fishes
http://www.ag.auburn.edu/fish/directory/faculty/wright.php 10/21/2008
Fisheries and Allied Aquacultures: Auburn University Page 2 of 3
EFFECTS OF COPPER SULFATE TREATMEhTS
ON OFF-FLAVOR AND LEVELS OF DISSOLVED Wildlife Trends 2002
COPPER IN CHANNEL CATFISH PONDS
Exploring Ecological Mechanisms Underlying
Largemouth Bass Recruitment along American Fisheries Society 2002
Environmental Gradients
Bythotrephes cederstroemi in Ohio Reservoirs:
I
Evidence from Fish Diets Ohio Journal of Science 2002
Liming Fishponds ANR 2001
revised
Evaluating How Local- and Regional-Scale

Processes Interact to Regulate Growth of Age-0 Transactions of the American
2000
Lar emouth Bass
Fisheries Society
Overwinter Growth and Survival of Largemouth

Bass: Interactions among Size, Food, Origin Transactions of the American
2000
,
11 1 1. -
and Winter Severity Fisheries Society
RelativeWeight: An Easy-to-Measure Index of ANR 2000
Fish Condition
Proceedings of the Annual
Fish Population and Angler Responses to a 406- Conference Southeast
mm Minimum Length Limit for Largemouth
.
. - .
Association of Fish abnd 2000
Bass on Lake Eufaula, Alabama-
Georgia Wildlife Agencies
Predicting How Winter Affects Energetics of

Age-O Largemouth Bass: How Do Current Transactions of the American
1999
11 Models Fare? Fisheries Society
Stock Characteristics and habitat use of

catfishes in regulated sections of 4 Alabama Southeastern Association of
1999
the Fish and Wildlife Agencies
rivers
From Star Charts to Stoneflies: Detecting

Relationships in Continuous Bivariate Data Ecology 1998
Overwinter growth and survival of age-0

largemouth bass (
Mic
ropterus
salmoides): Canadian Journal of Fisheries
1998
revisiting the-role-
of
bod s
ize and Aquatic Sciences
Selective Predation by Blue Crabs on the
Gastropod, Bittium varium: Confirmation From Estuaries 1996
0 ercula Found in the Sediments
Predator-prey dynamics in an ecosystem

context Journal of Fish Biology 1994
Recurrent response patterns of a zooplankton

community to whole-lake fish manipulation Freshwater Biology 1994
Direct and Indirect Effects of Southern
Flounder Predation on a Spot Population: Proceedings of Gutshop 1994
Experimental and Model Analyses
Growth and diet composition of largemouth
bass (Micropterus salmoides) from four
experimental lakes
he effects of predation on the survival and
i Internationale Vereinigung Fur
Theoretische Und Angewandte
Limnologie
Environmental Biology of
1994
size - d
stribution of Estuarine fishes: an
experimental approach
Fishes 1993
Roles of Fish Predation: Piscivory and

101-a-Advory The Trophic Cascade in Lakes 1993
Fish behavior and community responses to

manipulation The Trophic Cascade in Lakes 1993
Impacts of Variation in Planktivorous Fish on

Abundance of Daphnids: A Simulation Model of Food Web Management, A
1992
the Lake Mendota Food Web
Case Study of Lake Mendota
NON-ADDITIVE IMPACT OF BLUE CRABS AND
SPOT ON THEIR PREY ASSEMBLAGES
Survival of channel catfish virus in chilled, Ecology 1989

_.._ _ ..
frozen, and decom _osiI'll I ng channel catfish 1 progressive Fish-Culturist

1 1 1973
http://www.ag.auburn.edu/fish/directory/faculty/wright.php 10/21/2008
Fisheries and Allied Aquacultures: Auburn University
32 Records Total
Department of Fisheries & Allied Aquacultures
203 Swingle Hall I I Auburn University I Auburn, Alabama 36849
Phone: [phone] Fax:[phone] E-mail: [e-mail]
@ 2006 Copyright Regulations
Page 3 of 3
http://www.ag.cuburn.edu/fish/directory/faculty/wright.php 10/21/2008
ki r?
FosterVLake
11
?H Pond Management
October 7, 2008
S&EC
Attn: Kevin Martin
Dear Kevin:
I appreciate you contacting me in regards to your current lake project. I've put together
some of our opinions and recommendations to help with the situation.
• A one-acre pond has limitations on how many trophy fish it can produce.
Approximately 100-150 pounds of fish can be grown in an unfertilized acre of
water. If only 20-25% of these fish are largemouth bass (in a balanced system),
the possibility of growing a "trophy" fish (6+pounds) is limited. A larger lake
allows for a higher number of trophy fish to be produced, based on water volume.
• Because of the lack of volume, small ponds have a higher chance of becoming
overpopulated with forage fish. This kind of overpopulation can lead to stunting
and health problems.
• Lakes (8-acres and up) can produce larger numbers of trophy fish.
• Forage species such as threadfin shad and gizzard shad survive better in larger
lakes. The larger systems provide more areas for the fish to hide and thrive.
Also, large lakes tend to provide more surface area of cool temperatures,
promoting greater survival during the extreme heat of the summer.
• Small shallow ponds have a tendency to get overpopulated with nuisance aquatic
vegetation which limits plankton growth, forage production, spawning activities
and access to forage.
To summarize, a one-acre pond is going to be very limited in how many trophy bass it
can produce. The volume of water simply does not allow for a significant number of fish.
If trophy bass management is the primary objective for constructing the lake, I suggest
making it at least 5-8 acres based on our 30+ years of managing ponds for bass
production in NC..
Thanks,
Mitchell Morton
Manager/Fisheries Division
Fisheries Biologist
RESUME
John (Johnny) Foster
President, Foster Lake & Pond Management, Inc.
183 Donmoor Ct.
P.O. Box 1294
Garner, NC 27529 USA
919-772-8548
Fax: [phone]
E-mail: iohnnyna,fosterlake.com
Education:
Graduated Garner Senior High School in 1970
Graduated with B.S. in Fisheries and Marine Science from North Carolina State
University in 1974
Additional studies include: Biological and Agricultural Engineering, Integrated Pest
Management, Agricultural Waste Management, Aquaculture and Business
Management.
Career Experience:
February, 1983 to present - Owner of Foster Lake & Pond Management, (formerly
AAS-Aquaculture Advisory Service), a private aquaculture information service
including consultations, lake management, sport fish production and
equipment/supplies sales.
January, 1979 to January, 1983 - Aquaculture Advisor and Field Director for
University of North Carolina Sea Grant Aquaculture Demonstration Project in
Aurora, North Carolina.
March, 1978 to January, 1979 - Field Director of North Carolina State University Eel
Culture Project in New Bern, North Carolina.
January, 1975 to March, 1978 - Research Technician for the North Carolina State
University Eel Culture Project.
Publications:
Techniques for Culturing the American Eel, W.L. Rickards, W.R. Jones and J.E.
Foster. 1978. Proc. of World Mariculture Society, Vol. 9, p. 641-646.
A Feeding Tray for Use in Eel Farming, W.L. Rickards, J.E. Foster and W.L. Jones.
1978. Univ. of North Carolina, Sea Grant Pub. UNC-SG-78-04.
Clam Gardening, J.E. Foster. 1981. Univ. of North Carolina Sea Grant Pub.
UNC-SG-81-03.
Aquaculture, Johnny Foster. 1982. A series of 22 newspaper columns distributed
by Univ. of North Carolina Sea Grant.
Carolina Aquaculture News, John E. Foster. 1983 - 1988. A bimonthly subscription
newsletter distributed by AAS-Aquaculture Advisory Service.
Practical Aquaculture & Lake Management, John E. Foster. 1988 - 1992. A bimonthly
magazine distributed by AAS-Aquaculture Advisory Service.
Professional Organizations:
North American Lake Management Society
North Carolina Lake Management Society
International Erosion Control Association
International Erosion Control Association - North Carolina Chapter
Professional Landcare Association
Community Associations Institute
Community Associations Institute - North Carolina Chapter
Council for Entrepreneurial Development
Garner Chamber of Commerce
National Association of the Self Employed
American Farm Bureau Federation Aquaculture Advisory Committee, (1983 - 1987
1991 - 1994, chairman 1987)
North Carolina Farm Bureau Aquaculture Advisory Committee (chairman: 1983 -
1994)
North Carolina Crawfish Growers Association, (1987 - 1991; Board of Directors 1987 -
1988)
Civic Organizations:
Garner Volunteer Fire Department, Inc., (1984 -1997); Board of Directors 1987; vice-
president 1988; President 1989 - 1994
Garner Rotary Club; Board of Directors - 1986, 1988, 1991, 1994, 2001, 2002, 2005
President-elect: 2007 - 2008
Member of Group Study Exchange Team to the Philippines in 1981
-z 1 , C ,
J. Aqw- d. Mani XIonage. 34: 48-50
Lake size, Aquatic Macrophytes, and
Largemouth Bass Abundance in Florida Lakes:
A reply
HARK V. HOS'FR AI\rD DANIEL E. CANFIELD JR
tVe thank the journal of Aquatic Plant Management for
stretching the size limit set for their papers and allowing us
to list all the data we used in the paper titled "Largenio uth
bass abundance and aquatic vegetation in Florida Lakes: All
Empirical Analysis." Our intention was to allow everyone the
ability to use and interpret the daft using their overt insights,
as Maceina (1996) has already done. Thus, c->ne of our objec-
thrs has already been met. We Feel the process of making
data easily available to other researchers is healtlrv for sci-
ence and should he incorporated more often in other Jour=
nals as well as gray literature.
We also thank Maceina (19911) for trying to support the
hypothesis we put forward that aquatic truacrophyte abun-
dance may be more important to largemouth bass popula-
tions in large than small lakes. A major problem with
Matceina's analysis, howrvcr, is that the data lie used from
l foyer and Canfield (19911) was designed to examine the
relationships among largemouth bass populations, aquatic
tnacrophyte abundance and lake trophic status but not lake
size. The lakes were selected along a lake trophic gradient
From oligoh-ophic to hypereutrophic and within each
trophic category lakes were selectee) that had tnacrophyte
coverage ranging front <I0!-( to over 75c/r•. Splitting the data
set at 51 ha as Maceina (1996) did, yielded two data sets that
do not cover the whole tinges of lake tophic states.
The lakes with silt face areas above and below, 54 ha have
significantly diflevent trophic state variables (Table 1), with
the small lakes tending toward oligotophic systems and
large lakes tending toward hvpereutoplik systems. The
third data set Maceina used with lakes greater than 116 ha
also average hyj.)creutophic, Thus, any relationships
described by Maceina (1996) should be used will) the knowl-
edge that they were developed on subsets of data froin lakes
that do not incorporate the whole range of lake trophic
states, which can lead to erroneous conclusion when extrap-
olating relationships to real world populations of lakes.
As one example, Maceina (1996) suggests that the
approach of incorporating phosphorus and nitrogen seques-
tered in plants to those in the water column allowed Hoyer
and Canfield (1N96) to have a true analysis of trophic state
a.sso6ations, but mask the influence of aquatic plants on
largemouth bass population charactealstics. Ile suggests ilia(
in the lakes greater than 54 and 116 ha, the relations
between adjusted chlorophyll aand largemouth bass popula-
tions characteristics were either non-e),istent or much weaker
than those described by PAC or PVI alone. 11`e believe that
Maceina's (1996) findings are simply, because of the scale of
48
analysis (Duarte and I14111T 19110) and that the lake greater
than 54 and 116 ha were all nutrient rich systems yielding a
small range of lake trophic states to show any relations. Sev-
eral studies, using a wide range of lakes, have shown the
importance of lake tophic status to fish standing crop and
yield (Oglesby 1977; Jones and iloyer 1982) and largemouth
bass standing crop and yield (iloyer et al. 1963; Ploskey et al.
19811). Thus, Maceina's (1996) suggestion is a good example
of the clanger in splitting ll.oyer and Canfield's (19)6) data
by lake size.
While we feel the data set from lloyer and C:artfielcl
(1496) is not the proper one to unravel the relations among
largemouth bass population characteristic and lake size, we
do believe that lake size is important to the,. functioning of
lake systems. It has long been suggested that lake siie and
morphology determine in part the general produc tivity of
lakes (Rawson 1939), with large deep lakes being less pro-
ductive than small shallow lakes. The importance of the lit-
toral zone to overall lake production along a lake size
gradient has also been addressed. Rourisef'rll (1946) sug-
gested that area of fertile shallow wairr, which is gene rally
much less in proportion to total area in the larger lakes than
in smaller ones, as indicated by differences in length of
shoreline. Thus, it circular lake of 503 acres has a shoreline
of 3.14 miles, car 0,00624 stiles per acre, while one. o1' 50,200
acres hats a shoreline of only 31 42 stiles, or 0.000626 miles
per acre, OF about one-tenth as nrtuc h shoreline per acre.
Rcnmrsefell (1946) runduded that the s11.11lov+., fertile auras
usually are relatively match less extensive in file larger lakes.
0[her invrstigalots also suggest that the sources of organic
matter from the littoral zone playa major role in the metabo-
lism of many lakes, especially small lakes with a decreasing
importance in large lakes (F'4.etzel 1973; Sculthorpe 190).
How aquatic macrophytes affect these generalities about
large and sma.11 lakes will he determined by the quantity, and
distribution of aquatic plaratns in a lake. he most important
environmental factors affecting the abundance of aquatic
macrophytes in lakes have been identified as general water
chemistry (Beal 1977; Kadono 1982; Honer et al. 19911), lake
trophic characteristics (Spence 1967; 1lutchinson 1975), sub
state characteristics (Pearshall 1920; Barko et al. 19.46), light
availability (Canfield et al. 1985), prevailing winds (Duarte
and Kalif 1986) and lake morphology (Pearshall 11117;
Duarte and Kalff 1986). These factors can work indepen-
derttly and in combination, varying with the scale of analysis
(Duarte and R lfT 1990). The facto is also stuggrtit that lakes
can be clivided into Pour general grumps, small and la igr shal-
.J. Aqu.ral. Plant AffL7 agn 34: 1996.
I ism t. I. A%+iLA(;1, AAI I IF.S FOR LAKES I-Rr4PHIC 5I A rF. VARIARI G FOR Lkus <51 sire where aquatic nracroph) tes are needed to supplement
nl, ,54 m is,, ANn >I Ili im. Trlr•. s'rANDAPD FRRUR (IF 1111; . MPAN IS RECUROEO IN shoreline habitats.
PARENTHESES. THE OArA ARE. Willi I10YRR AND CANF(FLD ( 1996).
Lakes,54 ha I-Aes 51 ha lakes 116 ha
Tiophii SQne Variahlos (Ti..f i (n 32)
L
(n - )n
Total phosphomm (µg, l.) 16 (4) 91 (35) 41 (11)
Rual nitmgcn (µg/l.) 570 (70) 1250 (IW 1,170 (260)
Idomphyll a (gg/l.) m(3)
tl (ll1) hl (11)
Svcchi depth tin) 2.5 (0.3) 1.4 (0.2) L3 (0.2)
Add'mmydchtorophyll a 27 (6) l17 (1.,) 88 (24)
low lakes with abundant aquatic macrophytes, and small and
huge deep lakes with sparse aquatic macrophyces. This
rrsults from the littoral zone of lakes being inversely related
to hasi.n slope, depth, and to the degree of regularity of the
shoreline.
ItiViien lakes arc- shallow and the above factors are favor-
able for aquatic Inacrophyle growth, lake coverage can he
substantial in lakes with small or large surface areas. As
aquatic macrophyces fill the water colunul of a lake, studies
have shown signilii ant relations bctween aquatic macrophyte
abundance and lake water chemistry (Canfield et al. 1983),
phytoplankton population scruchrrc and biomass levels
(handers 1982). sediment resuspensictn and wave action,
periplt)ton and invertebrate populations (Gin-aneo and
[?alfl 1980), fish growth, abundance, and populalion struc-
ture (Wiley ct al 1981; Ganfield and Iloyer 19412); angler ufi-
liration of fish populations (Colle et al. 14)87); aquatic bird
abundance and species composition (Hover and Canfield
1991) and ina) other litnnologic•al processes (Ilutchinson
1975). The magnitudes of these relations are generally in
proportion to the abundance of aquatic nacrophytes.
In ;stall and large deep lakes there is less littoral area for
aquatic mast rophytr growth than in shallow lakes. The
imp(ntattce of aquatic macrophytes to the overall function-
ing of these lakes decreases proportionately as lakes get
Lager and deeper (Rounsefell 19=16; Tilrer and Serruya
1990). do some cases, however, small areas of littoral habitats
may play a limiting factor For the reproduction nr recruit-
ment of some aquatic organisms in huge lakes 1411 no( the
overall production of the organisms. (;asith (1091) used
I akr Kinneret (170 km') as all example, tAherc year class
trengilis of a dt)minant pelagic Push (Alinx,7'ex derrccrsanrl.ae)
were related to the availability of specialized littoral habitat.
Shallow lakes can also have limited littoral zone with low
aquatic ntacrophyie abundances because of natural circUm-
stances or lake management activities (e.g., aquatic macro-
phytr control with herbicides, biocontrol, or mechanical
harvesting). The proportion of shoreline habitat to whole
lake area in shallow lakes, without aquatic macrophytes, also
decreases as lake surface area increases (Gasilh 1991). This is
where we hypothesize that in shallow Florida large lakes,
ttithom aquatic macrophytes, shoreline habitat is not
enough for successful largemouth bass ('ecruitniCilt. In these
fakes aquatic macrophytes can increase the recruitment of
Lugemoulli bass to the carrying caparit) of lilt lakr system. If
this li)pothtsis is correct, the next step is to define the lake
LITERATURE CITED
Cc 6
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and their consideration in the managumcm ol'.sthnu•rsed vegctuion ,A
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Duarte, C. M. and J. Kiehl. 199. l.itl,.)ral slope as is predirfor of flit naaxi-
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Duane, C. M and,!. IWfl. 14110. I'attern.s in suhmcrgc•d olio tophcle biomass
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large deep lakes? Will, Internal. Vermin. Uninol. 24: 107:1-1076.
!lover, Nl. V, D. L. Uanficld it., J. V. Shire-man, and D. F;. (:oil(-. 1985. Rela-
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toulip between a MIJ ante u iii-genon ass an su )merged vegeta..
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toyer, M. V. and D. F. Cantietd Jr. 1991. Bird abumlanx::n,d species rirh•
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Ploskev G R , i . R. Aggus. \V M Bixin, aucl R. M. jt•nkinn. 19811. Regression
equations fit prrdicting felt standing crop, angl•i use, mud spur I lists vie Id
for the Unitt-d Sates restrvoii... I Sh11'SGLFI /:\8865. 1. S. I')sh and
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.1..-lqual. Pleir d Man.agrr. 34: 1996• 49
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