<s>
MT3D	B-Application
is	O
a	O
family	O
of	O
finite-difference	B-Algorithm
groundwater	O
mass	O
transport	O
modeling	O
software	O
,	O
often	O
used	O
with	O
MODFLOW	B-Application
.	O
</s>
<s>
The	O
first	O
generation	O
,	O
MT3D	B-Application
,	O
was	O
developed	O
by	O
Chunmiao	O
Zheng	O
in	O
1990	O
,	O
and	O
most	O
recently	O
released	O
by	O
the	O
U.S.	O
Geological	O
Survey	O
with	O
MT3D-USGS	B-Application
.	O
</s>
<s>
Improved	O
to	O
support	O
new	O
transport	O
modeling	O
capabilities	O
from	O
MODFLOW	B-Application
.	O
</s>
