1
Puddle
Model
Dirk
F.
Young
Environmental
Fate
and
Effects
Division
Office
of
Pesticide
Programs
2
Considerations
for
Puddle
Model
Design
°
Scarcity
of
puddle
hydrology
and
contaminant
research
°
Complexity
of
other
parts
of
avian
terrestrial
model
°
Must
capture
obvious
salient
processes
°
Must
be
suitable
for
Monte
Carlo
type
simulations
Simple
Model
3
Puddle
Design
Overview
(
2
coupled
mixing­
cell
models)

°
Field
mixing
zone
model
 
Curve
number
method
 
Fixed
depth
of
mixing
 
1
compartment
Field
mixing
cell
Puddle
Cpuddle
Cfield
Rain
Runoff
°
Puddle
model
 
Varying
volume
 
1
compartment
4
Puddle
Interception
of
Runoff
Runoff
Puddle
Intercepted
Runoff
Area
(
Aeffective)

Agricultural
Field
Qpuddle
=
q
x
Aeffective
q
from
curve
number
method
Qpuddle
5
Field
Mixing
Zone
Model
Cfield
Precipitation
Infiltration
Runoff
field
field
,

d
effective
,

s
effective
,

w
field
,

d
effective
,

s
field
,

s
effective
,

w
field
,

aq
effective
field
C
K
m
V
K
m
V
P
A
dt
dC








+
µ
+

µ
+

 

=
hmix
6
Puddle
Hydrology
Overflow
Infiltration
(
I)

Runoff
Input
(
Qp)

Actual
depth
(
Vp)
Evaporation
(
E)

Max
depth
(
Vmax)

Vp=
V0
+
Qpt
+(
P
 
I
­
E)
Apt
Precipitation
(
P)
7
Puddle
Pesticide
Hydrology
(
non­
overflow
condition)
p
d
p
p
S
d
p
a
p
p
t
K
0
,

field
puddle
p
M
K
m
V
K
m
V
IA
e
C
Q
dt
dM
field








+
µ
+

µ
+

 

=
 
(
)
t
A
I
E
P
t
Q
V
V
p
in
0
p
 

 

+

+

=

Qpuddle,
Cfield
E,
0
I,
Cp
P,
0
Cp
Aqueous
and
Sorbed­
phase
degradation
8
Puddle
Pesticide
Hydrology
(
overflow
condition)
Qwashout,
Cp
I,
Cp
Qin
,
Cin
Cp
p
d
p
p
washout
S
d
p
a
p
p
t
K
field
puddle
p
M
K
m
V
Q
K
m
V
IA
e
C
Q
dt
dM
field








+
+

+

+

 

=
 
µ
µ
0
,
Vp=
Vmax
9
I,
Cp
Cp
p
d
p
p
S
d
p
a
p
p
p
M
K
m
V
K
m
V
IA
dt
dM








+
+

+

 

=
µ
µ
Puddle
Pesticide
Hydrology
(
puddle
diminishing)

(
)
t
A
I
E
V
V
p
0
p
+

 

=
Evap
10
List
of
Inputs
Weather
°
Storm
Duration
°
Rain
Amount
°
Evaporation
Rate
Puddle
Properties
°
Depth
°
Sediment
mass
°
Puddle
Area
°
Runoff
Area
°
Infiltration
Rate
Field
Properties
°
Curve
Number
°
Bulk
density
°
Porosity
°
Mixing­
zone
depth
Pesticide
°
Aqueous
degradation
°
Sorbed
degradation
°
K
d
°
Timing
°
Amount
11
Parameter
Uncertainty
°
Puddle
runoff
interception
area
°
Sediment
mass
at
equilibrium
in
puddle
°
Puddle
area
°
Puddle
depth
°
Field
mixing
zone
depth
°
Puddle
infiltration
rate
°
Time
after
application
until
rain
event
°
Storm
duration
°
Rain
amount
°
Evaporation
rate
°
Curve
number
°
Porosity
°
Bulk
density
°
Pesticide
properties
Not
well
known
Better
Characterized
12
Preliminary
Parameter
Sensitivity
Work:

Area
Producing
Runoff
for
Puddle
(
Aeffective)

0
1
2
3
4
5
6
0
5
10
15
20
25
Hours
Puddle
Conc.

(

mg/

L)
10
m
100
m
1000
m
2
2
2
Aeffective
13
Preliminary
Parameter
Sensitivity
Work:

Soil
Interaction
Depth
(
hmix
)

0
2
4
6
8
10
0
5
10
15
20
25
Hours
Puddle
Conc.

(

mg/

L)
0.5
cm
1
cm
2
cm
3
cm
4
cm
5
cm
hmix
14
Summary
°
Puddle
and
runoff
modeled
with
2
mixing
cells
in
series
°
Level
of
complexity
consistent
with
other
avian
terrestrial
model
components
°
Parameter
estimation
issues
