Surface Water Concentration Calculator
               User Manual
         USEPA/OPP 734F14001
                 June 12, 2014
  Meridith Fry, Karen Milians, Dirk Young, He Zhong
      Environmental Fate and Effects Division
               Office of Pesticides
    United States Environmental Protection Agency
             Washington, DC 20460
          Technical Contact Information:
                 Dirk F. Young
       U.S. Environmental Protection Agency
                Washington, DC
              young.dirk@epa.gov

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Overview
The Surface Water Concentration Calculator (SWCC) estimates pesticide concentrations in water
bodies that result from pesticide applications to land.  The SWCC is designed to simulate the
environmental concentration of a pesticide  in the water column and sediment and is used for
regulatory purposes by the USEPA Office of Pesticide Programs (OPP). The SWCC uses PRZM
version 5.0+ (PRZM5) and the Variable Volume Water Body Model (VVWM), replacing the
older PE5 shell (last updated November 2006), which used PRZM3 (Carousel et al., 2005) and
EXAMS (Burns, 2003). This updated model will improve users' interactions with the program
and facilitate maintenance and operation of the software.

Installation and Launching
The SWCC can be installed by obtaining the installation file (SWCC.msi) from an appropriate
location. Internet users can access SWCC at:
(http://www.epa.gov/pesticides/science/models_db.html while EFED personnel can also go to
the G drive Model Repository.  Clicking on the msi file will install all necessary components of
the SWCC.  The SWCC should be installed to a directory where the user has administrative
rights.   After installation, SWCC can be launched by double-clicking on the SurfaceWaterGUI
icon, which is saved in the model setup directory.

Menu
File manipulations in the SWCC are performed from the top
Menu bar.
JU SurfacewaterCalulator
  File  Scenario   Help
                                                                Retrieve All Inputs

                                                                Save All Inputs
File
    >  Retrieve All Inputs will open a file browser and allow the user to upload a previously
       created input file (*.SWI)  into the user interface.   All information  necessary for a
       simulation is recorded in the input file, including the scenario and pesticide information.
       The input files are text files that can be created either within the interface or within a text
       editor.

    >  Save All Inputs will open a file browser and allow the user to select a directory to save the
       inputs from the interface to a text file (Note: Output files will be saved in the same
       directory).

Note 1: Using File Save and File Retrieve will automatically specify the working directory
where the output file will be saved. Always save your work to the directory where you wish
the output to be located. The working directory and name of the output files are given in
the status section of the SWCC at the bottom left side as shown below.
                                         Ready...

                   Working Directory: J:\SurfaceWaterCalculator\Package\

                   IO Family Name:   test

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Note 2: The File Save routine stores information for a simulation in a text file (*.SWI).
Users do not need to interact with these text files to run the SWCC. However, users
wishing to externally manipulate these files for advanced processing can find the structure
of the *.SWI file in Appendix A.
Scenario
                                                           jjtt SurfacewaterCalulator
       Retrieve Scenario Info Only will load only the
       scenario information from a scenario file (*.scn).
       Scenario filenames should be a maximum of 50
       characters.
          File

          Chem
                                                                  Scenario
     Help
Retrieve Scenario Info Only
Save Scenario Info Only
Retrieve Old PE5 Scenarios
    >  Save Scenario Info Only.  Scenarios created within the SWCC interface can be saved
       with this menu option.

    >  Retrieve OldPES Scenarios will load scenario files (tab-delimited text files) that are in
       the PE5 format.  This feature maintains backward compatibility.

Note : Scenario files are stored as text files. Users do not normally need to interact with
these files as the SWCC creates them for you. However, users wishing to externally
manipulate these files for advanced processing can find the structure of the *.SCN file in
Appendix B.
Help
Help contains this guidance and the developer's contact information.
Chemical Tab

For Parent Compound:
Sorption Coefficient (mL/g): Enter the value
of the sorption coefficient in this text box, and
then select whether it is a Koc or Kd value.

          Koc (mL/g): Selecting the Koc radio
           button indicates to the program that
           the partitioning coefficient (Kd) is to
           be  calculated  by  multiplying   the
           sorption  coefficient  by  the  OC
           content   of   each   horizon   (see
           Scenario: Crop/Land tab).
          Kd (mL/g):  Selecting the Kd radio
                                                 U SurfaceWaterCalulator
File  Scenario  Help
Chemical | Applications || Cropland II Runoff II Water Body || Batch Runs |

                       Parent   DegrSatel

0 Koc O Kd  Sorption Coeff (mL/g)
Water Column Metabolism Halflife (day)
   Water Reference Temperature (*C)
     Benthic Metabolism Halflife (day)
  Benthic Reference Temperature (C)
     Aqueous Photolysis Halflife (day)
        Photolysis Ref Latitude D
          Hydrolysis Halflife (day)
             Soil Halflife (day)
                soil ref (T)
            Foliar Halflife (day)
                   MWT
           Vapor Pressure (torr)
             Solubility (mg/L)

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          button indicates to the program that the sorption coefficient is the Kd value entered
          directly into the program without adjustment.  All  soil layers will have the same Kd
          with this option.

Water Column Metabolism* Half-life (days): This input represents a degradation half-life that
applies  to  all  forms of the chemical  in  the water column  (typically  the  aerobic  aquatic
metabolism  half-life in an OPP/EFED assessment). This includes forms sorbed to suspended
solids and dissolved organic carbon (DOC) as well as dissolved forms of the chemical. The half-
life that is entered should correspond to the water column reference temperature entered below.
A value of zero or a blank is a signal to the program that this degradation process does not occur
for this chemical.

Water Reference Temperature (C):  This value is the temperature at which the water column
degradation  applies. During a simulation, the degradation rate will change according to a Q10
assumption,  with  the entered temperature and degradation half-life as the references. Q10 is the
factor by which degradation changes over 10C.

Benthic  Metabolism* Half-life (days): This  input, also  known as the  metabolism  rate
representative of  the sediment (e.g., anaerobic aquatic half-life), represents a degradation half-
life that applies to all forms of the chemical in  the benthic layer.  This includes forms sorbed to
sediment and DOC, and dissolved forms of the chemical in pore water.  The  half-life entered
should correspond to  the benthic temperature  reference entered below.   (See  note below
regarding the use  of the word metabolism.) A value of zero or a blank is a signal to the program
that this degradation process does not occur for this chemical.

*Note that the word metabolism is  used in these  descriptions because in a typical USEPA
regulatory application these inputs would correspond to  the  bacterial metabolism  degradation
studies; however, these inputs can be used to represent any degradation that  occurs in  the
compartment benthic or water column on all forms of the chemical.)

Benthic Reference Temperature (C): This number is  the  temperature at which the benthic
degradation  half-life applies. During a simulation, the degradation rate will change according to
a Q10 assumption, with the entered temperature and degradation half-life as the reference points.

Aqueous Photolysis Half-life (days):  This input represents  the 24-hour average near-surface
photolysis rate as  typically derived from photodegradation in water studies submitted to OPP. A
value of zero or a blank is a signal to the program that this degradation process does not occur
for this chemical.

Photolysis Reference Latitude (): This value is the  latitude at which the photolysis test was
designed to represent (e.g., 40).

Hydrolysis Half-life (days): This value represents the relevant hydrolysis half-life in the water
body (the hydrolysis rate  is not applied to the  field degradation). Typically, the hydrolysis rate
for pH 7.0 is used for standard EPA water bodies.  If a non-standard water body with a different
pH is used, users  may enter the relevant hydrolysis rate that corresponds to the appropriate pH.

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A value of zero or a blank is a signal to the program that hydrolysis does not occur for this
chemical.  The hydrolysis rate only applies to the top aqueous-phase compound. (Although the
term hydrolysis is used here, this degradation input could  be used for any degradation that is
believed  to  occur only  in  the  aqueous phase; i.e., this  is a straight-forward rate with no
manipulations to the input for temperature, pH, or any other environmental factor.)

Surface Soil Half-life (days): This input represents the total system half-life, typically obtained
from a degradation test conducted on moist soil (aerobic soil metabolism).  The program applies
the associated  degradation rate  to both the soil and aqueous phases. If the  soil  temperature
simulation option is used, then this degradation rate should correspond to the rate conducted at
the temperature entered  as  the Soil Reference Temperature (see below).  If the  temperature
simulation option is not used, then the soil degradation rate  is constant for the entire simulation.
Entering a zero or a blank indicates to the program that soil degradation does not occur.

Soil Reference Temperature (C): This number is the temperature at which the soil degradation
half-life applies.  If the PRZM temperature simulation option is used during a simulation, the
degradation  rate will change according to a Q10 assumption, with the entered temperature and
degradation half-life as the reference points. The Q10 assumption is based on an equation which
corrects for temperature dependent  degradation; a factor for rate increase  when  temperature
increases by 10C.

Foliar Degradation Half-life (days): This value represents the half-life of a pesticide on foliage.
Entering a zero or blank signals to the program that  foliar degradation does not occur.

MWT (g/mol): This  input represents the molecular weight of the chemical.   It is used in the
water body volatilization routine  and in the degradate production routine.

Vapor Pressure (torr): This value is the vapor pressure of the chemical and  is used only in the
volatilization calculations for the water body.

Solubility (mg/L): This input is the  solubility of the chemical in water and is used only in the
volatilization  calculations for the water body.   The program does  not limit the  pesticide
concentration in water; the solubility limit can be exceeded.

Degradate 1 Check Box:  Checking this box allows for the simulation of a daughter degradate
of the parent.  Chemical  properties of the degradate should be entered as described above for the
parent.

Degradate 2 Check Box:   (Note:  This box is only available if the Degradate 1 Check Box is
checked).  Checking this  box allows  for the simulation of a daughter degradate of degradate  1
(granddaughter of parent).  Chemical properties of this degradate should be entered as described
above for  the parent.

Molar Conversion Factors:  These factors are the ratios  of moles of degradate produced to
moles of parent degraded for each of the processes.  For example, if one parent molecule breaks

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down and  produces one degradate, then the ratio is  1. If the process does not produce  the
degradate of interest, then the ratio is zero.
Applications Tab
 Sitt Surface Water Calculator
   File   Scenario   Help
-  n x
   Chemical | Applications | Crop/Land | Runoff | Water Body  Batch Runs  Out: Pond  Out: Reservoir || Out: Custom Advanced

    Number of Applications

         25~
O Absolute Dates
 Relative Dates

Days Since
Emergence
123

Amount
(kg/ha)
CZ
Application Method




Foliar Depth
Ground
] 
I Incorporate I T-Band
O
O O
O
O Custom
O Reservoir
O Pond
Depth T-Band
(cm) Split Eff. Drift
| | QQ ?|
Number of Applications:  Up to 50 pesticide applications per year can be specified. When the
number of applications is altered, the user must click the  Update Applications button, and then
only the relevant applications will be shown.  The number of rows in the table will equal the
number of applications (Note: The number of applications will also be registered at run time if
the Update Applications  button is not pressed).   Unless otherwise  specified, these  applications
will repeat for every year of the simulation.

Absolute and Relative Application Dates:  By selecting the appropriate radio button, pesticide
application dates can be entered as absolute dates by specifying the day and the month (e.g., Day
=31 Mon =1 for January 31), or as dates relative to the emergence date (e.g., 10 days since
emergence).

Specify Years: This checkbox will  reveal another set of text boxes  that allows a user to specify
the exact year at which  the application  occurs. This may be used, for example, in validation
studies where the exact date is known.

Amount: This value refers to the applied mass of the pesticide in kg/ha.

Application Method:  The application method  specifies the way in which  the  pesticide is
applied. There are 5 methods available:
1. Ground (entirely surface applied,  distributed linearly decreasing to 4 cm in the profile),
2.  Foliar (Pesticide is distributed to the canopy in proportion to its areal coverage, the remainder
         is applied as a ground application as above),
3. Incorporate (uniform incorporation into the soil to a user-specified depth),
4. @Depth (placed entirely in a single compartment at a user-specified depth),
5.  T-Band (a fraction of the chemical is applied in the top 2 cm, and the remainder is  applied
         uniformly between 2 cm and the user-specified depth).

Depth (cm):  This  number refers to the depth of pesticide incorporations for the Incorporate,
@Depth, and T-Band application methods (see above).

T-Band Split: This input is the fraction  of the application rate that will be applied to the top 2
cm in a T-band application.

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Eff.:  This value is the efficiency, which is a multiplier of the application rate in PRZM. It is
used to reduce the actual applied mass to the field, without changing the input application rate
(has utility when performing spray drift applications). The efficiency does not affect spray drift
calculations.
Drift:  The spray drift fraction is used to calculate drift loading.  Typically for aquatic ecological
exposure assessments (pond), use 0.05 for aerial spray, 0.01 for ground spray, or 0.03 for orchard
air blast.  In drinking water assessments (Reservoir), use 0.16 for aerial spray,  0.064 for ground
spray,  or 0.063 for orchard air blast. Refer to Input Parameter  Guidance for more information
(USEPA, 2006)

Custom, Reservoir, or Pond:  Drift and efficiency are water-body
specific parameters according to OPP/EFED policy.  Therefore, the
SWCC allows each type of water body (Pond, Reservoir, or Custom)
to be parameterized differently  with respect to drift and efficiency.
Using  the radio buttons above the Eff and Drift labels (see adjacent
figure) allows the user to enter different values for each water body.
| Out: Custom | Advanced |
                                                                  th T-Eand
                                                                  }   Split
           Custom
           ' Reservoir
           Pond
         Eff.  Drift
        1.0
        .99
        .98
                                                                              0.05
                                                                              .01
Application Refinements:

   Applications occur:  This input includes user-specified frequency
of applications (every number of years)  and the interval.  Interval  is
defined as year  1  to  any number of years less than what  is in the
meteorological file.   The word last  represents the  last year in the
meteorological file. For example, a simulation  could  be run in which
applications of pesticide occurred only for the first 15 years, and then
no more applications were made for the remaining years.  This could be
done by entering 1 into the "from year" box and 15 into the "to year"
box. If applications were to occur for every year of that 15-year period,
a 1 would be entered into the "Applications occur every years(s)" box.
Such an example could show the environmental recovery time after a
pesticide use had ceased.

Application Window Batch Analysis:
   Apply  Pesticide Over a Time Window:  Selecting this check box
will initiate a  batch run of simulations with different  application dates
as specified by Window (days) and Skip (days).  Output is delivered to
a summary file in the Working directory.
        Specify Years
        Application
        Refinements

    Applications occur every
        1
      Applications occur
       from year  1
        to year  last
     Application Window
       Batch Analysis
       Apply Pesticide over
        a Tiime Window
     20  Window (days)
    flj~| Step (days)

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    Window:  When using the time window, this  value is the length of the window.  For
example, specification of a 100-day window (and a 1-day skip) would start a batch run using the
first specified application  day and end the batch runs after 100 simulations had run each with a
different application day varied by one day.

    Step:  When using the time window, step specifies how many days are between each of the
batch runs.   For example,  if the window is  10 days and the step is 2 days, then 6 batch
simulations  would  occur  for applications on 0, 2, 4, 6, 8, and 10 days added to  the original
application date.

    Example:  If one wishes to examine the impact of application day on a pesticide use, the
model user would check the "Apply Pesticide over a Time Window" box.  For Example, the first
day of applications could  vary over a 14-day period from  June 1 to Jun 14 due to variations in
planting day or weather conditions.   In this case, the user would  specify the  Window as 14. If
the user wanted to investigate every possible starting date application, then the interval should be
specified as 1.  In some cases, where the window is longer (e.g., 200  days), a user may want to
only check every other day or every 5 days in order to save computation time.  In these specific
cases, the user would enter 2 or 5, respectively, into the Skip box.  Output is sent to a Summary
file that allows the user to  identify sensitive times for applications.  Note that when multiple
applications are used, each application window works the same for all of the applications.
Crop/Land Tab
 U Surface Water Calculator
   File  Scenario  Help
   Chemical | Applications | Crop/Land | Runoff || Water Body | Batch Runs | Out: Pond || Out: Reservoir | Out: Custom | Advanced]

   Scenario ID
   Weather File
For a  standard  OPP/EFED simulation,  the  values  in  this tab are specified by the  standard
scenarios.  Users will likely not interact often with this page.  For scenario development or
research applications, this page facilitates scenario creation and manipulation.  See the PRZM5
manual and OPP guidance for population of parameters.

Weather File:  This button opens a file browser t for selecting weather files. Files must be in
the same format as PRZM weather files. SWCC will automatically select the correct weather file
when the user retrieves a scenario.
Growth Descriptors
Note: The following tabs or fields will be automatically filled in with the scenario and weather
profile.
    Day Month Emerge:  Enter the day  and
month when the crop emerges from the ground.
 Growth Descriptors
Day Month
         Emerge
         Mature
         Harvest
                                                                        Root Depth (cm)
                                                                        Canopy Cover (%)
                                                                        Canopy Height (cm)
                                                                        Canopy Holdup (cm)

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This value is the start day for canopy and root development.

   Day Month Mature:  Enter the day  and month when the crop reaches its maximum size.
This number is the day when the maximum root depth and the maximum canopy coverage are
attained.

   Day Month Harvest: Enter the day and month when the crop is removed. This value is the
day when the root depth and the canopy coverage are returned to zero.

   Root Depth (cm):  Enter the  maximum root depth of the  crop.  Root depth is used in
evapotranspiration calculations and in the irrigation calculation.  Any depth can be used, but
because of the vertical  discretization scheme, root  depth  should  be rounded to the nearest
centimeter for  depths up to 20 cm and then to the nearest 20 cm for root depths greater than 20
cm (i.e., 20, 40, 60 cm).

   Canopy Cover (%):  Enter the maximum areal coverage of the crop canopy.  Canopy
coverage affects the amount of pesticide that is directly applied to the ground when pesticides are
applied over the canopy. Canopy coverage also has a small effect on the amount of rainfall that
reaches the ground.

   Canopy Height (cm): Enter the height of the crop at maturity.  This value is used only for
PRZM volatilization calculations. However since  field volatilization is not operational in this
SWCC version, the canopy height parameter has no effect on output).

   Canopy Holdup (cm):   This parameter along with the canopy  cover (%) determines how
much water can be stored in the canopy.

Hydro Factors:
   Pan Factor:   Values for the  vast majority of the U.S.  range from 0.7 to  0.8.  PRZM
multiplies the pan evaporation values in the weather file by the Pan Factor to estimate potential
evapotranspiration (See the PRZM5 manual for typical values).

   Snowmelt  Factor (cm/C/day):  This value is the amount of   Hydro Factors
accumulated snow that melts per C above 0 C.  Typical values
for open agricultural areas are in the range of 0.4 to 0.5 (See Table          pan Factor
5.1 of Carousel et al., 2005 for more detailed values).                    ~ gnowmen Factor
                                                                     Evaporation Depth (cm)
   Evaporation Depth (cm):  This parameter is the minimum
depth  of  the  soil  that  can be  used to  satisfy  the  potential
evapotranspiration.   If the root depth is  greater than this value,
then PRZM uses the soil water up to the root depth to satisfy evapotranspiration.  If the root
depth is less than this depth, then  PRZM uses this minimum value.  Generally, the evaporation
depth ranges from  10 to 35 cm, depending on location (See Figure 5.2 of Carousel et al., 2005
for details).

Post-Harvest Foliage:
	B                                                  Post-Harvest Foliage

                                                                        Surface Applied
                                           9                           O Removed
                                                                       O Left as Foliage

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   For a foliar applied pesticide, determine how the pesticide remaining on the foliage is to be
handled.  It can be handled in one of the following ways:

   Surface Applied: Pesticide remaining on the foliage is applied to the ground. ?
   Removed: Pesticide remaining on the foliage is removed from the simulation.

   Left as Foliage: The pesticide remains  in the simulation as attached to foliage and can be
       washed off even after harvest.
Irrigation (auto-populated):

   Irrigation Type:  Choose one of the three  irrigation types:  None  (no irrigation, default
selection), Over Canopy irrigation, or Under Canopy irrigation.

   Extra Water Fraction: Enter the amount of extra water for leaching (as a fraction of the
demand) beyond that which is  required to meet the crop demand. Out of the total water required
to satisfy the demand, some fraction of additional water may be desirable to wash out salts.
   Allowed Depletion:   Enter the degree
(%)  to  which  the  available water in  the
active root can be depleted before irrigation
is required.
                                            lmgaticin
                                            0 None
                                            O Over Canopy
                                            O Under Canopy
                                              Extra Water  Allowed
                                                Fraction   Depletion
                                                       Max Rate
   Max Rate of Water Supplied (cm/hr):  Enter the limit to the amount of water that can be
supplied. Because PRZM operates on a daily time scale, this value should be adjusted to account
for the fact that this rate will be applied over the entire 24-hour period. For example, if 1 cm of
water is applied per day, then the max rate should be 0.042 cm/hr (1/24), regardless of how fast
the actual delivery equipment can produce for short periods.
Soil Layers:

 Soil Layers
  Number of Horizons
      6
                         Simulate Temperature
  Thick
Max.  Min.
Cap.  Cap.
O.C.    N
                                            10

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    Number  of Horizons:   Enter the  total number of soil  horizons  and click  the  Update
Horizons button.  The user can  define the soil properties in each horizon by  the following
parameters:

        Thick: thickness of the compartments in the horizon (Thick, cm)

        p: effective porosity in the horizon (p),

        Max Cap:  maximum water holding capacity for the tipping bucket method. For lack of
        a better parameterization, the USEPA has historically used field capacity for this value
        (cm3 cm"3).

        Min  Cap: minimum capacity. The USEPA has traditionally used the wilting point for
        this value (cm3 cm"3).
        O.C.: organic carbon in the horizon (%)

        N: number of compartments in the horizon.

Simulate Temperature:  The user can decide whether to include a temperature simulation, in
which case additional soil properties need to be entered.
Runoff Tab
Day Mon  CN C N  Table: These values
specify the day, month, curve numbers, and
USLE erosion parameters  (universal  soil
loss cover  management factor  [C]  and
manning's n factor [N]) for  up to 50 times
per year.
                                            Chemical | Applications | Crop/Land |i,iJHnJLi Watershed | Batch Runs | Out
                                               No. of
                                             Time-Varying
                                               Factors
  Day Mon CN  C   N

1  16  2
                                               26
                                               Specify year
         89   .188  .011

21   3   89   .130  .011
3 16  3   89   .131  .011

414   89   .527  .011

5 16  4   89   .558  .011

61   5   89   .569  .011

7 16  5   94   .572  .011

3 ~
                                                           n  1C  C
                                                                    94  .574  .011
USLE K:  Specifies the universal soil loss
equation of soil erodibility.  See PRZM manual.

USLE LS:  Specifies the universal soil loss equation topographic factor. See
PRZM manual.

USLE P:   Specifies the universal soil loss equation practice factor.  See
PRZM manual.

IREG:  Specifies location of NRCS 24-hour hyetograph.  See PRZM manual.

Slope: Specifies the slope of the hydraulic flow path. See PRZM manual.
                                                                                USLE K
                                                                                USLE LS
                                                                                USLEP
                                                                                IREG
                                                                                Slope
                                           11

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Specify Years: This checkbox will reveal another set of text boxes that allows a user to specify
the exact year during which the event  occurs. This  number may be used  for  example  in
validation studies where the exact date is known.
PRZM Runoff and Erosion Extraction (New For PRZM5):

   R-Depth (cm): Enter the lowest depth at which runoff interacts with the soil.
                                     PRZM5 Runoff & Erosion Extraction

                                     Distribution of Runoff in Surface
Distribution of Eroded Solids
   R-Decline  (I/cm):  Enter the
exponential   decline   of  runoff
interaction as a function of depth.

   Efficiency:  Enter  the amount
of runoff that interacts with the soil.
   E-Depth  (cm):    Enter  the
lowest depth at which erosion interacts with the soil.

   E-Decline (I/cm):  Enter the exponential decline of erosion interaction as a function  of
depth.
R-Depth (cm)
R-Decline (1/'cm)
Efficiency

2.0

1.55

0.266
E-Depth (cm)
E-Decline (1/cm)

0.1

0


Watershed Tab

Simulation Type:  Users  can select the EPA Pond, EPA Reservoir, and
user-defined custom water body in the same run.  Users can choose among
three different types of custom runs: varying volume with flow through,
constant volume with flow through, or  constant volume without flow
through.  Users  also have the option to choose  a  reservoir with  user-
specified flow-through averaging as does PMRA Health Canada.

Sediment Accounting: The default setting is for no sediment burial, but the
user may  select sediment burial. This input allows for a first-order solute
removal mechanism based  on the sediment delivery rate  to the benthic
region.
         Chemical | Applications | Crop/Land | Runoff |~V
          Simulation Type

          GZ] EPA Pond

          0 EPA Reservoir
              Use Row Averaging (days)
            User-Defined Water Body
            Choose one or none?:
          [7] Varying Volume 4 Flowthrough
          D Constant Volume No Flowthrough

            Sediment Accounting

              No Burial

             O Burial
                                                                               PRBEN  0.5
PRBEN:   This value specifies how the pesticide associated  with eroded
solids is distributed between the water column and the benthic regions.  The
default  value of 0.5 specifies that half is placed in  the benthic region and half in the water
column. A value of one distributes all into the benthic region, whereas a value of zero places all
in the water column.

Watershed and Water Body Dimensions:    The watershed  and water body dimensions are
given here for the selected water bodies. A Cropped Area Fraction can be entered and represents
                                            12

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the fraction of the watershed that actually receives pesticide. Default values for the EPA Pond
and the EPA Reservoir cannot be changed.
                        1CCCCC
                        1CCCC
Watershed and Water Body Dimensions

                     EPA Pond

       Field Area (m^
  Water Body Area (m^
       Initial Depth {m)
       Max Depth (m)
   Hydraulic Length I'm)
 Cropped Area Fraction
                        35S.S
                                 EPA Reservoir   User Defined
          10000
          4.2
          Is
          GOO
          1.0
Water Body Physical Parameters
The physical parameters are the same as those defined in the VVWM documentation.  Checking
the USEPA/OPP defaults box will reset all values to the standard water body parameters and will
lock them.


  Water Body Physical Parameters
                         Q USEPA/UPP defaults

           Water Column Parameters          Benlhic Parameters

                   DFAC  1.15          Benthic Depth (m)  0.05
      Water Column SS (mg/L)  30
           Chlorophyll (mg/L)  0.005
           Water Column foe
    Water Column DOC (mg/L)
                       0.04
  Water Column Biomass (mg/L)  0.4
   Benthic Porosity  0.5
Bulk Density {g/cm3)  1.35
       Benthic foe  0.04
Benthic DOC (mg/L)  5
                                 Benthic Biomass (g/m2)  0.006
                                     Mass>ferCoeff.lrn/s)  1E-OS
Batch Runs Tab
Multiple scenarios can  be run if desired. The buttons on this
tab  open  a file  browser so  that  users can select specific
scenarios for batch runs.  Typical Windows-type file selection
methods can be used to  select specific sets.  For example, using
"*CA*" in the file browser for file will select all  California
scenarios,  whereas "*corn*"  will  select all corn  scenarios.
Multiple  files  can be  selected using  the  standard  browser
functions associated with the Shift and Ctrl keys.
                                                               D Do a Batch Run
                                              13

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Output is delivered to a summary file. Users can analyze the summary file and identify scenarios
in need of more analysis. Information presented in the summary file should be sufficient to
identify problematic scenarios.

Output Tabs
Out: Pond: This output tab gives results for the EPA Pond and user-defined water bodies.

Out: Reservoir: This output tab gives results for the EPA Drinking Water Reservoir.

Out: Custom:  This output tab gives results when not using the EPA Pond and EPA Drinking
Water Reservoir.

The graphs on these two output tabs show annual peaks for the water column and benthic pore
water.

Concentrations:                     Absolute Peak = 0.0
                             Water Column 1-in-10 year Cone, (ppb)
                           Peak
                       365-day Avg
                       Entire Mean

   Absolute Peak: Highest peak of the entire simulation (ppb).

   Peak (acute): Upper 90th ranked annual    peak of the simulation (ppb).

   4-day:  Upper 90th ranked annual 4-day average of the simulation (ppb).

   21-day:  Upper 90th ranked  annual 21-day  average of the simulation (ppb).

   60-day:  Upper 90th ranked  annual 60-day average of the simulation (ppb).

   365-day Avg (chronic): Upper 90th ranked annual average of the simulation (ppb).

   Simulation Average:  Mean value of all daily concentrations in the simulations.


21 -day Avg
60-day Avg


    l-in-10  Benthic  Peak:    Upper  90th  ranked
    annual benthic pore water peak of the simulation
    (ppb).
  Benthic 1-in-10 Yr Cone, (ppb)
     Pore Water    Total/Dry Sed
Peak
   Total/Dry Sed: Concentration in sediment (ppb).    21 'dsy Avg L
                                                        Sediment Bioavailable Fraction
   l-in-10  Benthic 21-day:   Upper  90th  ranked
   annual 21-day average of benthic pore water for
   the simulation (ppb).
                                           14

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    Total/Dry Sed: Concentration in sediment (ppb).
    Sediment Bioavailable Fraction:    Fraction  of total chemical in the benthic region that
resides in the pore water.

    Relative Transport:
    Runoff: This value is the fraction of pesticide mass that moved to the       Relative
water body by runoff (pesticide moved to water body by runoff / pesticide       Transport
that entered  water body by all  means)  It is calculated  over the entire   Runoff
simulation.                                                                 Erosion
                                                                             Drift
                                                                                       r-
                                                                              Fraction from
                                                                              Field to Water
    Erosion: This input is the fraction of pesticide mass that moved to the
water body by erosion. It is calculated over the entire simulation.

    Drift: This value is the  fraction of pesticide mass that  moved to the
water body by drift. It is calculated over the entire simulation.
    Fraction from Field to Water: This input is the  fraction of the  pesticide applied to the
    field that moved into the water body.
    Effective Half-lives:  These values report the
    effective half-life of each  of the processes
    (days).  The total values  represent the overall
    effective   half-life   of   the    respective
    compartment (i.e., water column or benthic).
                                                       Effective Water
                                                     Column Halflives [day]
Effective Benthic
 Halflives [day)
Washout
Metabolism
Hydrolysis
Photolysis
Volatilization
Total






Burial
Metabolism
Hydrolysis
Total





Advanced Tab
    This tab is primarily used by the developers and will change frequently as developer needs
arise. For more information, contact the developer, whose information is supplied in the Help
menu and on the first page of this document.
     jUi Surface Water Calculator
      File   Scenario   Help
      Chemical || Applications | Crop/Land | RunoH | Water Body \\ Batch Runs || Out: Pond | Out: Reservoir Out: Custom Advanced
         Password
                                             15

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16

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                APPENDIX A: Surface Water Input File Format

Input files for the  SWCC (*.SWI files)  are created by the  interface and store  all of the
information needed  for a SWCC simulation. There is no required format or positioning of the
values within the lines. However, lists of numbers on the same line must be comma-delimited.
The line location for the information stored is as follows:
Line 1.  Chemical ID info (text)
Line 2.  Number of parent and degradates (1 to 3 values)
Line 3.  True if K0c; false if Kd
Line 4.  Sorption coefficient values, mL/g, (Parent, Degradate 1, Degradate 2)
Line 5.  Water metabolism half-life, days, (Parent, Degradate 1, Degradate 2)
Line 6.  Water metabolism reference temperature, C, (Parent, Degradate 1, Degradate 2)
Line 7.  Benthic metabolism half-life, days, (Parent, Degradate 1, Degradate 2)
Line 8.  Benthic metabolism reference temperature, C, (Parent, Degradate 1, Degradate 2)
Line 9.  Aqueous photolysis half-life, days, (Parent, Degradate 1, Degradate 2)
Line 10. Photolysis reference latitude, degrees, (Parent, Degradate 1, Degradate 2)
Line 11. Hydrolysis half-life, days, (Parent, Degradate 1, Degradate 2)
Line 12. Soil half-life,  days, (Parent, Degradate 1, Degradate 2)
Line 13. Soil reference temperature, C, (Parent, Degradate 1, Degradate 2)
Line 14. Foliar half-life, days, (Parent, Degradate 1, Degradate 2)
Line 15. Molecular weight, g/mol, (Parent, Degradate 1, Degradate 2)
Line 16. Vapor pressure, torr, (Parent, Degradate 1, Degradate 2)
Line 17. Solubility, mg/L, (Parent, Degradate  1, Degradate 2)
Line 18. Water Column Metabolism Molar Conversion Factor (Parent to Degradate 1, Degradate
1 to Degradate 2)
Line 19. Benthic Metabolism Molar Conversion Factor (Parent to Degradate 1, Degradate 1 to
Degradate 2)
Line 20. Photolysis Molar Conversion Factor (Parent to Degradate 1, Degradate 1 to Degradate
2)
Line 22. Hydrolysis Molar Conversion Factor (Parent to Degradate 1, Degradate 1 to Degradate
2)
Line 22. Soil Molar Conversion Factor (Parent to Degradate  1, Degradate  1 to Degradate 2)
Line 23. Foliar Molar Conversion Factor (Parent to Degradate 1, Degradate 1 to Degradate 2)
Line 24. Unused.
Line 25. Unused
Line 26. Unused
Line 27. Q10 factor
Line 28. Number of pesticide applications
Line 29. List of comma-delimited days of month of the applications
Line 30. List of comma-delimited months of the applications
Line 31. List of comma-delimited application rates, kg/ha (count = Line 28)
Line 32. FALSE if years are not explicitly entered; TRUE if the years of applications are
specified;
Line 33. List of comma-delimited years of the applications (Required if Line 32 is TRUE)

                                           17

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Line 34. List of comma-delimited application methods (integer representations)
Line 35. List of comma-delimited efficiency for custom applications (fraction)
Line 36. List of comma-delimited drift for custom applications
Line 37. List of comma-delimited efficiencies for pond applications (fraction)
Line 38. List of comma-delimited drift for pond applications
Line 39. List of comma-delimited efficiency for reservoir applications (fraction)
Line 40. List of comma-delimited drift for reservoir applications
Line 41. List of comma-delimited depths of incorporations, cm
Line 42. List of comma-delimited relative application days
Line 43. TRUE if application dates are absolute; FALSE if they are relative to planting
Line 44. List of comma-delimited T-band depths
Line 45. Unused
Line 46. Unused
Line 47. Unused
Line 48. Scenario ID (string)
Line 49. Full path and file name of the weather file
Line 50. Unused
Line 51. List of Boolean indicators for the simulations to be bunned: EPA Reservoir, EPA
Pond, VVWM, VVWM Constant Volume w/Flow, VVWM Constant Volume w/o Flow.
Line 52. TRUE if Reservoir averaging is used, number of averaging days
Line 53. TRUE if burial; FALSE if no burial
Line 54. Field area for custom water body, m2
Line 55. Waterbody area for custom water body, m2
Line 56. Initial depth for custom water body, m
Line 57. Maximum depth for custom water body, m
Line 58. Mass transfer coefficient, m/s
Line 59. PRBEN
Line 60. Benthic depth, m
Line 61. Benthic porosity
Line 62. Bulk density g/mL
Line 63. Benthic foe
Line 64. Benthic DOC, mg/L
Line 65. Benthic biomass
Line 66. DFAC
Line 67. SS
Line 68. Chlorophyll
Line 69. Water column foe
Line 70. Water column DOC
Line 71. Water column biomass
Line 72. Use EPA defaults for physical parameters (Boolean)
Line 73. Fraction Cropped Area Reservoir, Fraction Cropped Area Custom
Line 74. Unused
Line 75. Emergence day of month
Line 76. Emergence month
Line 77. Maturity day of month
Line 78. Maturity month
                                          18

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Line 79. Harvest day of month
Line 80. Harvest month
Line 81. Root depth, canopy height
Line 82. Canopy cover
Line 83. Canopy holdup
Line 84. Post-harvest foliage 1,2,3
Line 85. PFAC
Line 86. SFAC
Line 87. Evaporation depth
Line 88. Flag: 0= No irrigation; 1= Over canopy; 2= Under canopy
Line 89. Extra leaching water fraction
Line 90. Allowable depletion for irrigation
Line 91. Maximum irrigation rate ( average daily in cm/hr)
Line 92. USLEK
Line 93. USLELS
Line 94. USLEP
Line 95. IREG
Line 96. Slope
Line 97. Hydraulic length for custom waterbody
Line 98. Number of soil layers
Line 99. List of comma-delimited thicknesses
Line 100.  List of comma-delimited bulk densities
Line 101.  List of comma-delimited maximum capacities
Line 102.  List of comma-delimited minimum capacities
Line 103.  List of comma-delimited organic carbon percentages
Line 104.  List of comma-delimited numbers of increments in layers
Line 105.  List of comma-delimited sand percentages
Line 106.  List of comma-delimited clay percentages
Line 107.  Albedo
Line 108.  Temperature at lower boundary, C
Line 109.  TRUE to simulate temperature; FALSE for no temperature simulation
Line 110.  Number of erosion /runoff factors
Line 111.  List of comma-delimited days of month for the runoff/erosion event
Line 112.  List of comma-delimited months for the runoff/erosion event
Line 113.  List of comma-delimited curve numbers for the runoff/erosion event
Line 114.  List of comma-delimited C factors for the runoff/erosion event
Line 115.  List of comma-delimited Manning's n values for the runoff/erosion event
Line 116.  Runoff interaction depth (cm), decline (I/cm), bypass
Line 117.  Erosion interaction depth (cm), decline (I/cm)
Line 118.  TRUE if specific years used for erosion/runoff; FALSE if the events occur every year
Line 119.  List of comma-delimited years for the runoff/erosion event (used if Line 112 is
TRUE)
                                          19

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                       Appendix B: Scenario File Format

The Scenario file (*.SCN) is exactly the same as the SWI file, starting at line 48 of the SWI File.
The SCN File line number format is therefore as follows:

Line 1. Scenario ID (string)
Line 2. Full path and file name of the weather file
Line 3. Unused
Line 4. List of Boolean indicators for the simulations to be bunned:  EPA Reservoir, EPA Pond,
   VVWM, VVWM Constant Volume w/Flow, VVWM Const Volume w/o Flow.
Line 5. TRUE if Reservoir averaging is used, number of averaging days
Line 6.  TRUE if burial; FALSE if no burial
Line 7.  Field area for custom water body, m2
Line 8.  Waterbody area for custom water body, m2
Line 9.  Initial depth for custom water body, m
Line 10. Maximum depth for custom water body, m
Line 11. Mass transfer coefficient, m/s
Line 12. PRBEN
Line 13. Benthic depth, m
Line 14. Benthic porosity
Line 15. Bulk density g/mL
Line 16. Benthic foe
Line 17. Benthic DOC, mg/L
Line 18. Benthic biomass
Line 19. DFAC
Line 20. SS
Line 21. Chlorophyll
Line 22. Water column foe
Line 23. Water column DOC
Line 24. Water column biomass
Line 25. Use EPA defaults for physical parameters (Boolean)
Line 26. Unused
Line 27. Unused
Line 28. Emergence day of month
Line 29. Emergence month
Line 30. Maturity day of month
Line 31. Maturity month
Line 32. Harvest day of month
Line 33. Harvest month
Line 34. Root depth, canopy height
Line 35. Canopy Cover
Line 36. Canopy holdup
Line 37. Post-harvest foliage 1,2,3
Line 38. PFAC
Line 39. SFAC
Line 40. Evaporation depth

                                        20

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Line 41. Flag: 0= No irrigation; 1= Over canopy; 2= Under canopy
Line 42. Extra leaching water fraction
Line 43. Allowable depletion for irrigation
Line 44. Maximum irrigation rate ( average daily rate in cm/hr)
Line 45. USLEK
Line 46. USLELS
Line 47. USLEP
Line 48. IREG
Line 49. Slope
Line 50. Hydraulic length for custom waterbody
Line 51. Number of soil layers
Line 52. List of comma-delimited thicknesses
Line 53. List of comma-delimited bulk densities
Line 54. List of comma-delimited maximum capacities
Line 55. List of comma-delimited minimum capacities
Line 56. List of comma-delimited organic carbon percentages
Line 57. List of comma-delimited numbers of increments in layers
Line 58. List of comma-delimited sand percentages
Line 59. List of comma-delimited clay percentages
Line 60. Albedo
Line 61. Temperature at lower boundary, C
Line 62. TRUE to simulate temperature; FALSE for no temperature simulation
Line 63.  Number of erosion /runoff factors
Line 64.  List of comma-delimited days of month for the runoff/erosion event
Line 65.  List of comma-delimited months for the runoff/erosion event
Line 66.  List of comma-delimited curve numbers for the runoff/erosion event
Line 67.  List of comma-delimited C factors for the runoff/erosion event
Line 68. List of comma-delimited Manning's n values for the runoff/erosion event
Line 69. Runoff interaction depth (cm), decline (I/cm), bypass
Line 70. Erosion interaction depth (cm), decline (I/cm)
Line 71. TRUE if specific years used for erosion/runoff; FALSE if the events occur every
   year
Line 72. List of comma-delimited years for the runoff/erosion event (used if Line 112 is
   TRUE)
                                          21

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