<s>
Visual	B-Application
MODFLOW	I-Application
(	O
VMOD	B-Application
)	O
is	O
a	O
graphical	B-Application
interface	I-Application
(	O
GUI	B-Application
)	O
for	O
the	O
open	O
source	O
groundwater	O
modeling	O
engine	O
MODFLOW	B-Application
.	O
</s>
<s>
VMOD	B-Application
was	O
developed	O
by	O
Waterloo	O
Hydrogeologic	O
and	O
first	O
released	O
in	O
1994	O
,	O
the	O
first	O
commercially	O
available	O
GUI	B-Application
for	O
MODFLOW	B-Application
.	O
</s>
<s>
In	O
May	O
2012	O
a	O
.NET	B-Application
version	O
of	O
the	O
software	O
was	O
rebranded	O
as	O
Visual	B-Application
MODFLOW	I-Application
Flex	I-Application
.	O
</s>
<s>
The	O
program	O
includes	O
proprietary	B-Application
extensions	O
,	O
such	O
as	O
MODFLOW-SURFACT	O
,	O
MT3DMS	O
(	O
mass-transport	O
3D	O
multi-species	O
)	O
and	O
a	O
three-dimensional	O
model	O
explorer	O
.	O
</s>
<s>
Visual	B-Application
MODFLOW	I-Application
supports	O
MODFLOW-2000	O
,	O
MODFLOW-2005	O
,	O
MODFLOW-NWT	B-Application
,	O
MODFLOW-LGR	O
,	O
MODFLOW-SURFACT	O
,	O
and	O
SEAWAT	O
.	O
</s>
<s>
The	O
original	O
version	O
of	O
Visual	B-Application
MODFLOW	I-Application
,	O
developed	O
for	O
DOS	B-Device
by	O
Nilson	O
Guiguer	O
,	O
Thomas	O
Franz	O
and	O
Bob	O
Cleary	O
,	O
was	O
released	O
in	O
August	O
1994	O
.	O
</s>
<s>
It	O
was	O
based	O
on	O
the	O
USGS	O
MODFLOW-88	O
and	O
MODPATH	O
code	O
,	O
and	O
resembled	O
the	O
FLOWPATH	O
program	O
developed	O
by	O
Waterloo	O
Hydrogeologic	O
Inc	O
.	O
</s>
<s>
The	O
first	O
Windows	B-Application
based	O
version	O
was	O
released	O
in	O
1997	O
;	O
the	O
main	O
programmers	O
were	O
Sergei	O
Schmakov	O
,	O
Alexander	O
Liftshits	O
,	O
and	O
Sean	O
Wilson	O
.	O
</s>
<s>
A	O
.NET	B-Application
version	O
that	O
included	O
non-grid-based	O
,	O
graphical	O
conceptual	O
modelling	O
features	O
was	O
released	O
in	O
2012	O
.	O
</s>
<s>
On	O
May	O
1	O
,	O
2012	O
,	O
Waterloo	O
Hydrogeologic	O
released	O
Visual	B-Application
MODFLOW	I-Application
Flex	I-Application
.	O
</s>
