Document ID: EPA-HQ-OPP-2004-0005-0055
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-03-31T05:00Z

Puddle
Algorithm
Keep
it
simple
Input
to
other
Terrestrial
Level
II
Models
by
puddle
algorithm

Duration
of
water
standing
in
puddle

Pesticide
concentration
in
puddle
Pesticide
Concentration
in
Puddle

Approximately
equal
to
average
pesticide
concentration
in
surface
mixing
zone
after
runoff
starts
(
i.
e.,

p>
Ia)

C
M
W
t
I
W
p
Ia
W
a
=
 
 
 
 







exp(
)
exp
exp
µ
Assumes
that
the
water
in
the
puddle
is
small
compared
to
the
total
that
runs
in
There
are
better
ways
for
calculating
initial
abstraction
than
0.2S
Input
to
other
Terrestrial
Level
II
Models
by
puddle
algorithm

Duration
of
water
in
puddle

Pesticide
concentration
in
puddle
Time
that
water
stands
in
puddle
water
depth
in
puddle
Time
=
infilt
rate
+
evaporation
rate
Water
Depth
in
Puddle
Maximum
depth
of
puddle
for
large
storms
For
smaller
storms
contributing
area
Depth
=
q
pond
area
Puddle
Algorithm
summary
Hydrology
for
puddle
algorithm
can
be
simple.

Large
storms
all
puddles
are
filled
independent
of
model
chosen

Small
storms
calculate
initial
abstraction
and
runoff
PUDDLES!!

There
are
large
regional
differences
between
puddles
N
Y
State
(
Variable)
Puddles
New
England
(
Variable)
Puddles
puddles

High
groundwater
table

Compacted
soil
due
to
traffic
on
field

Variable
source
area
hydrology
as
a
consequence
of
topography
0%
probability
of
ponding
March
July
October
>
90%
probability
of
ponding
Puddles
Conclusions
Keep
the
hydrology
simple
and
allow
for
regional
differences
in
puddle
formation