United States
                                  Environmental Protection
                                   Robert S. Kerr Environmental Research
                                   Ada, OK 74820
                                  Research and Development
                                   EPA-600/S2-80-192  Jan. 1981
Project  Summary
                                  Predicting  Cattle  Feedlot
                                  Runoff and   Retention   Basin

                                  J. Ronald Miner, James K. Koelliker, and Marshall J. English
                                    As a result of potential water and
                                  land pollution from cattle feedlots, a
                                  technology  for control  of feedlot
                                  runoff has evolved.  This study de-
                                  scribes  a  procedure  for  controlling
                                  runoff while recovering manure-laden
                                  water for use as fertilizer. When rain or
                                  melting snow  reduces the surface
                                  holding capacity of a  feedlot's runoff
                                  retention basin, manure-laden water,
                                  valuable as a cropland fertilizer, may
                                  be lost to soil surface and/or receiving
                                  streams near the basin. Accurate pre-
                                  diction of the quantity of runoff enter-
                                  ing a retention  basin  or pond would
                                  permit design of a basin with a holding
                                  capacity sufficient  to  contain the
                                    A procedure was devised which can
                                  predict, on a daily basis,  the quality
                                  and quantity of feedlot runoff entering
                                  a retention basin. The predictions are
                                  based on climate, feedlot size, type of
                                  liquid-removal  equipment, frequency
                                  of pumping and the needed level for
                                  land or water pollution control.
                                    A  cattle  feedlot  in Illinois  was
                                  sampled to adjust  the  predictive
                                  model which measures the following
                                  parameters on  a daily basis: chemical
                                  oxygen  demand,   total Kjeldahl
                                  nitrogen,  ammonia  nitrogen, total
                                  phosphorous, total solids, fixed dis-
                                  solved solids,  total coliforms, fecal
                                  coliforms, and fecaf streptococcus. In
                                  order to determine quality  changes
                                  between a runoff retention  basin or
                                  other manure-laden water storage and
                                  the receiving soil surface, a separate
                                  study   was conducted.  Ammonia
                                  nitrogen is the major constituent lost.
                                  A technique was devised and tested
                                  for prediction  of ammonia nitrogen
                                  loss as a function of wastewater
                                  quality, sprinkler equipment charac-
                                  teristics, and current weather data.
                                  Losses  ranged from  zero to  40
                                    This project summary was devel-
                                  oped  by EPA's Robert S. Kerr Envi-
                                  ronmental Research  Laboratory  in
                                  Ada, OK, to announce key findings of
                                  the research  project  that is  fully
                                  documented in a separate report of the
                                  same  title (see Project Report ordering
                                  information at back).
                                    Runoff  from  cattle  feedlots was
                                  recognized as a potential water pollu-
                                  tant in 1962, following a series of-fish
                                  kills in Kansas; since that time, a tech-
                                  nology for control of feedlot runoff has
                                  evolved, accompanied  by a variety of
                                  regulatory  schemes.   The  strategy
                                  proven most feasible is the collection of
                                  stormwater runoff in a retention basin
                                  or pond. Following a storm, the manure-
                                  laden water is applied to cropland in a
                                  manner to avoid runoff. This approach
                                  recaptures  plant nutrients, thereby
                                  reducing the cost of chemical fertilizer,

Table  1.    Cattle Feedlot Runoff Retention Basin Quality Parameters to be
            Predicted in the Developed Model.
Chemical oxygen demand
Total Kjeldahl nitrogen
Ammonia nitrogen (NHs+NH4+)-N
Total phosphorus
Total volatile solids
Fixed dissolved solids
Total solids
Total coliforms
Fecal coliforms
Fecal streptococcus
No. /TOO ml
No./ 100 ml
No. /WO ml
some of which is replaced by the runoff
water. The capacity of a runoff retention
basin for a given location is a function of
climate,  feedlot  size,  availability  of
liquid-removal equipment, frequency of
pumping and the required level of pollu-
tion  control. Construction  of a basin
which could  retain all  runoff,  even
during the most extreme weather condi-
tions, is  unreasonably expensive and
provides only minimal additional pollu-
tion   control than  a  less  expensive
system   for   which   well-defined
limitations  exist.   Feedlot  pollution
control guidelines define the conditions
under which a discharge will occur in a
well-designed  feedlot runoff  control
system during extreme weather condi-
tions; typically, these are the  10-year,
24-hour storm and  the  25-year,  24-
hour storm.
  Cattfe  feedlot  runoff  is   a  high-
strength  organic  wastewater
containing large  numbers of  enteric
microorganisms. Qualityof runoff water
is highly variable, depending upon such
parameters as rate of rainfall, tempera-
ture,  and feedlot  surface  conditions.
Quality is further modified by storage in
the  runoff  control  system;  organic
matter  is  stabilized,  solids  settle,
ammonia  volatilizes, and enteric bac-
teria die off. All of these changes influ-
ence  the  quality  of basin  contents;
conversely,  the  rate  of  change  is
influenced by the quality of runoff water
in the basin.
  The quality and quantity of the dis-
charged material must be known, if its
impact on retention basin water is to be
accurately  predicted.  When  basin
contents are to be applied to cropland,
optimal application rates are a function
of  nitrogen  concentration.  Accurate
quality predictions are critical if optimal
nutritive values are to be fully realized.
  Previous   modeling  efforts   have
provided techniques for predicting the
size of runoff retention  facilities to
achieve various levels of runoff control
or  to  predict  the  runoff  retention
achieved  by various  combinations of
retention basin sizes and management
strategies. No previous  efforts  have
attempted to predict the quality of reten-
tion basin contents.
  The initial plan for this  effort was in
two phases. The first  phase was to
develop a predictive model to estimate
the pond  volume, liquid  temperature,
and liquid constituent  concentrations
listed in Table 1.
  Originally,  a  cattle  feedlot runoff
retention  basin   was to  be  sampled
simultaneously to  generate data for
calibrating the model. In Phase II of the
project, the model was to be verified by
the collection of  data in  an intensive
field study. Due to  changing research
priorities within the EPA, only Phase I of
the project  was  funded:  the develop-
ment  of  a  continuous water quality
model  which  will predict, on a  daily
basis,  the quality  of  feedlot runoff
                                          entering a  runoff retention basin and
                                          contained  in the  basin.  That  runoff
                                          would  be  discharged  in  case  of an
                                          uncontrolled event, or removed from the
                                          basin  for   subsequent  treatment,  or
                                          disposal on land. The predicted quality
                                          for  basin contents will be compared
                                          with analytical data based upon samp-
                                          ling a  cattle feedlot runoff retention
                                          basin  in eastern  Illinois during the
                                          summer of  1978
                                            In a separate but related effort, quality
                                          changes occurring  during the sprinkler
                                          application   of   anaerobically   stored
                                          liquid  manure  to  cropland   was
                                          investigated.  Those  data  are  also
                                          included in  this report.
  Originally, this project was to include
two additional years of feedlot runoff
and runoff retention basin sampling at
several locations, to confirm the validity
of the model and to better define varia-
tions in  the derived coefficients as a
function  of site-specific variables. Due
to  changes in  priorities  within  EPA,
funding was not provided beyond the
initial  phase;  therefore,  a degree  of
uncertainty remains concerning the
accuracy  of the reported coefficients
when  applied  to  sites  in  different
climatic and geographic regions.
  A technique was developed to predict
the quality of cattle feedlot runoff based
upon the various parameters. Using this
technique,  it  is  possible  to obtain a
better estimate  of this quality than by
any other known procedure. Previous
work by  the authors of this report and
others  has  provided  a   satisfactory
method of estimating runoff quantity in
response to climatic  data and feedlot
characteristics. The water quality model
of a runoff retention basin developed in
this project is based upon an analysis of
previously published data and intensive
sampling of a cattle feedlot in  Illinois.
The model represents the best available
technique for  predicting the quality of
runoff water used for land application
under  specific  climatic   conditions,
should  runoff  exceed   the  storage
capacity  of  the  retention  basin.  Daily
calculation  of  liquid  volume   in  a
retention  basin is  possible with  this
technique. Also, the following  water
quality parameters can be predicted:
COD, TS, FDS, TC. FC, and FS.
  Water  quality changes  between  a
storage reservoir and the  land surface
during the process of sprinkler irrigation

were  analyzed to document that  the
only  significant  change  was  NH3-N
volatilization.  Depending primarily on
pH  of the wastewater, volatilization of
NHs-N can range from  nearly zero to
over 40 percent. Other variables which
influence  NHa-N loss  are air tempera-
ture,  wind velocity, relative humidity,
droplet  size and travel distance of the
droplet.   The  predictive  technique
devised allows precise definition of this
nutrient loss.
Hydro logic Model
  The hydrologic model developed in
this study can predictquality of runoff in
the following stages: (1) entering the
retention  basin  after  running  off  a
feedlot surface and passing through a
solids trapping phase in a settling basin,
a porous dam, or a grassed waterway,
(2) contained in the retention basin, (3)
discharged from the retention basin by
uncontrolled events,  (4) removed for
subsequent  application to  land,  and
(5) deposited on the interception surface
of  the  land  treatment   area.   The
hydrologic   model  and  management
scheme provided the input quantities to
•determine how long material  has  been
in the basin and the extent of  its degra-
  This water quality  model comple-
ments  the  water  quantity models
developed previously under EPA grants
to Oregon State University and Kansas
State University. When completed, this
water quality model will provide a com-
plete  quality and quantity  model, to
provide a tool for evaluating the impact
of a cattle feedlot upon the waterquality
in a basin.
  The continuous watershed  model for
the hydrologic  portion  of  the feedlot
runoff control system has previously
been described by Zovne and Koelliker1.
The reader isdirectedtothatpuolication
for a complete description of the model.
Included herein is an abridged descrip-
tion.  Figure 1 shows a process sche-
matic of the feedlot runoff  model.  The
three components of the model are the
feedlot  runoff generating  surface, a
runoff retention   basin  and a   soil
moisture budget  model for the runoff
disposal area.
Zovne, J. J. and J. K. Koelliker. 1979. Application of
Continuous  Watershed  Modeling  to  Feedlot
IWm>« Managementand Control. EPA-600/2-79-
065,  U.S. Environmental  Protection Agency.
Washington, DC, 156 pp.
                                         Figure 1.
             Feedlot runoff generating
   For  the  purposes of the hydrologic
 model, the surface area of the feedlot
 must  be defined so that the  depth  of
 runoff produced times the area of the
 feedlot will  yield the runoff  volume.
 Likewise, the total surface area of the
 retention pond at maximum depth must
 be defined since the amount of precipi-
 tation  falling upon  this surface  is all
 added to the volume of the basin. The
 volume of  precipitation added to the
 basin  is then the daily depth of precipi-
 tation  times the maximum surface area.
 To determine evaporation from the
 pond,  the side slope, length, and width
 of a pond must be defined. Evaporation,
 considered to occur only from the actual
 surface area  of the liquid within the
 pond, is equal to the actual surface area
 times the predicted daily depth on pond
 evaporation. The volume removed for
 disposal is a function of the area of the
 disposal field to  which  liquid can  be
 applied by the disposal system times the
 depth  of liquid that  will  be appliled in
 one day. Therefore, the physical capa-
 bilities of the disposal system  must be
 defined in order to set the daily disposal
 volume.  Discharge  occurs  when the
 retention  pond  volume  is exceeded.
 Therefore,  a maximum pond depth  is
 also required.
  The deterministic water budget model
for the hydrology of the system is driven
by  daily   values  of  minimum  and
maximum  air temperature  and  daily
precipitation  from  a   continuous
weather record for a particular station.
Other  meteorological inputs required
are monthly mean values of air temper-
ature, solar radiation, relative humidity,
wind travel, percent sunshine, and A
and  B  coefficients  for  the  Brunt
equation. Other input data needed for
the feedlot  include a soil type in the
disposal area of only  12 classifications;
crop to be grown on  the disposal area;
the management system for operation
of disposal, if any; and the limitations of
                                          Table 2.    Inputs to the Hydrologic
 Physical characteristics of the system
     Feedlot surface area
     Surface area of retention basin at
     Retention basin dimensions and
      interior slopes
     Disposal Held
        Soil type (one of  12)
        Crop to be grown
        Management system
        Maximum application rale

 Climatic data
     Monthly mean data
        Air temperature
        Solar radiation
        Relative humidity
         Wind travel
        Percent sunshine
        Brunt equation coefficients
          A and B
     Daily values
        Maximum temperature
        Minimum temperature

 the amount of runoff applied in any one
 period,  if  any. These inputs  are sum-
 marized in Table 2.
  This  model  was developed  as  a
 technique to evaluate a particular feed-
 lot  in a particular location within the
 continental United States; it is consid-
 ered to  be the most rigorous hydrologic
 model that has yet  been developed for a
 feedlot  runoff  control   system.  All
 masses of constituents will be reported
 in kg/ha and all concentrations in mg/l

 Adaptation to Hydrologic
 Model for Water Quality
 Con sidera tions
  For purposes  of the water quality
 model, a unit feedlot area is considered.
 To accommodate this approach with the
 hydrologic model,  a  runoff control
 system  provides realistic runoff control
 at  a  particular   location.  Next,  all
 volumes generated in the hydrologic
 model are divided by the feedlot area to
 provide  values in terms  of a depth per
 jnit area of feedlot. Further, all depths
 are converted to SI units of cubic meters
per  hectare  (mVha).  This approach
allows fora simpler look at the quality of
runoff without complicating the  issue
with the  physical  size of the feedlot

runoff control system; i.e., the size of the
feedlot  has no influence  upon  the
quality of the  runoff water. However,
such factors as the shape and depth of
the pond may  have some influence on
water quality within the system at any
given time. The model's prediction of
feedlot runoff control quality is unlikely
to be precise enough to separate such
  For the water quality model, the daily
changes   in   liquid  volume   in  the
retention  basin in  m3/ha,  then is
described by:
       -DISVOL - DSCHRG (1)
     AV  = change  in  liquid volume,
RUNOFF  = feedlot   runoff  into   the
  PRECIP  = precipitation onto the basin
  SEVAP = evaporation   from   basin
 DISVOL = amount  of liquid removed
           by  disposal operation,  and
DSCHRG  = amount   of  liquid   dis-
           charged  by  uncontrolled

  Infiltration through the bottom of the
pond is assumed to be zero. Sludge is
the volume of solids that accumulates
within the retention pond as estimated
in the COD portion of the  model. The
volume of liquid within the pond at any
time per  ha of feedlot is equal to the
pond volume (PONVOL) yesterday, plus
AV  minus   the  increased   volume
occupied by the sludge.

Modeling Cattle Feedlot
Runoff Quality
  The cattle feedlot runoff process is a
complex  phenomenon  controlled  by a
variety of physical, climatological, and
environmental  factors.  An  effective
modeling effort requires  that these
factors are selectively handled to assure
that the end product is useful as a plan-
ning tool  even where in-depth local data
are not available.
  Although a fully satisfactory relation-
ship between  the  factors influencing
the cattle feedlot runoff process and
runoff  quality  has  not been achieved,
nor is  it likely to be achieved in the
future,   there   are   sufficient   data
available to use runoff quality as an
input in calculating the quality of runoff
retention basin contents. The structure
of this process utilizes commonly avail-
able climatic and physical data to make
the needed estimates. The following
basic  structure  is  inherent  in  the
process being proposed:
1.  Cattle  feedlot  runoff  is. an area-
    based  phenomenon;  hence,  the
    constituent   concentrations  are
    independent of feedlot size.
2.  Being an area-based process, the
    number of cattle on the lot is not an
    input to the process. This assumes
    the cattle are present in sufficient
    intensity to preclude the growth of
    vegetation,  but  not  at such  an
    intensity to inhibit efficient animal
    growth nor to  result in unsuitable
    lot conditions. Typically, this trans-
    lates  into an  animal  density of
    between 350 and 850 head per ha
    (1 50 and 350 head/ac).
3.  Some technique to remove easily
    settleable solids  from  runoff, prior
    tointroduction  of the runoff into a
    retention basin,  is a  function of
    sound  design; such a function is
    assumed to be part of this model.
    The technique  might involve use of
    a debris basin, grassed waterway,
    sedimentation  basin, porous dam,
    or any other device to provide short-
    term sedimentations.
4.  This is a calendar-based  model
    devised to  estimate  the  average
    concentration of runoff produced by
    the  precipitation  occurring on  a
    specific day.  For a storm  which
    occurs on two or more successive
    days,  each  day  is  treated

  The physical, chemical, and microbio-
logical quality of cattle feedlot runoff is
highly variable, not only  among sites
and separate storms but during  the
progress of a runoff event as well.
Field Sampling Program for
Data Collection
  The  basis for  selection of  an ideal
feedlot site from which to collect field
data was that the site be representative
of  typical  conditions  in  the  major
feeding areas of the United States; also,
a site was needed  which  would insure
several runoff events and disposal, from
the retention pond during  the testing
period. As much variation  as possible in
pond volume  and water  quality  as
desired to assure that the model would
be responsive to such changes. Since
our  sampling  program was  operated
during the  spring  and  summer, we
chose  a more humid region of the
country where rainfall was likely to be
more consistent. Previously, sampling
programs had been run at several feed-
lot locations in Illinois. Also,  previous
data were  available  in a form which
could be applied to evaluate the model's

Incorporation of Field Data
into Predictive Model
  Occasionally,  large   discrepancies
occurred  between   measured  pond
volumes and volumes predicted by the
hydrologic model. The nature  of these
discrepancies indicated that substantial
subsurface seepage  was entering the
pond, possibly originating in cultivated
fields adjacent to the  feedlot. These
spurious flows rendered  much of the
data  useless. As a consequence, only
data  collected  during a single 45-day
perod was considered reliable  enough
to be used for calibration of the model.
The accepted procedure for a modeling
effort of this sort calls for calibrating the
model  with one set of  data, and then
testing with a second set of data. How-
ever, because  of the subsurface flow
problem, the data collected were not
sufficient for an independent test of the
model. Because of the resultant data
limitations, simple calibration of the
model did not confirm the model, nor did
it adequately represent the ideal situa-
tion  upon  which the model  building
effort was posited.

Demonstration of the Model
  To demonstrate the model's ability to
predict  runoff  and  retention basin
quality,  a  simplified  weather  pattern
was adopted in which constant monthly
temperatures   were   assumed  and
discrete rainfall events were specified.
Those  simplifying assumptions allow
the influence of particular variables to
be noted so that the function of the
model can be viewed.  A runoff retention
basin having a  surface area equal to 35
percent of the feedlot surface area was
  Variations in cattle  feedlot runoff
quality were  expected to occur with
temperature,, rainfall  intensity  and pre-
vious rainfall for various dates on which
runoff was assumed to occur. The effect
of  precipitation  occurring as
accumulated snowfall is shown by the
runoff which occurred on specific dates
when  no  rainfall  occurred.  Januarv
temperatures were assumed to be stiff i-

ciently low  to  maintain  a snowpack;
hence, a  high concentrated runoff was
noted  as soon as  the  temperature
increased. Subsequent storms of  one.
two and three days duration are shown
for comparison purposes  to note the
effect of those variables on both runoff
quality and quantity.
  The impact that various runoff events
have on the pond liquid concentrations
were shown by measuring runoff reten-
tion basin quantity and quality. In all
cases,  the pond is assumed to have a
completely  mixed liquid layer overlying
a sludge layer. Thus, a runoff event has
an immediate effect upon the liquid con-
centration.  The periods during which
various constituents increased when no
runoff was occurring reflects the degra-
dation  of the  sludge layer releasing
soluble materials into the liquid portion.
Again, the model allows one to view the
impact of temperature and precipitation
on the rate of change of various consti-
tuents with time.
                                          J. Ronald Miner and Marshall J. English are with the Department of Agricultural
                                             Engineering, Oregon State University,  Corvallis.  OR 97331, and James E.
                                             Koelliker is with the Agricultural Engineering Department, Kansas State
                                             University, Lawrence, KS 66044.
                                          R. Douglas Kreis is the EPA Project Officer (see below).
                                          The complete report, entitled "Predicting  Cattle Feedlot Runoff and Retention
                                             Basin Quality." (Order No. PB 81-113045; Cost: $17.00, subject to change)
                                             will be available only from:
                                                  Nationat Technical Information Service
                                                  5285 Port Royal Road
                                                  Springfield VA 22161
                                                  Telephone: 703-487-4650
                                          The EPA Project Officer can be contacted at:
                                                  Robert S. Kerr Environmental Research Laboratory
                                                  U.S. Environmental Protection Agency
                                                  P.O. Box 1198
                                                  Ada,  OK 74820
                                                                                      - US GOVERNMENT PRINTING OFFICE: 1961 - 75.7-064/Oa 18

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