<s>
Flood	B-Application
Modeller	I-Application
is	O
a	O
computer	O
program	O
developed	O
by	O
Jacobs	O
that	O
simulates	O
the	O
flow	O
of	O
water	O
through	O
river	O
channels	O
,	O
urban	O
drainage	O
networks	O
and	O
across	O
floodplains	O
using	O
a	O
range	O
of	O
one	O
-	O
and	O
two-dimensional	O
hydraulic	O
solvers	B-Application
.	O
</s>
<s>
The	O
software	O
incorporates	O
a	O
user	O
interface	O
for	O
building	O
,	O
running	O
and	O
viewing	O
the	O
results	O
of	O
models	O
,	O
including	O
a	O
GIS	B-Application
map	O
interface	O
.	O
</s>
<s>
Flood	B-Application
Modeller	I-Application
was	O
previously	O
known	O
as	O
ISIS	O
software	O
(	O
named	O
after	O
the	O
local	O
name	O
for	O
the	O
Upper	O
Thames	O
)	O
.	O
</s>
<s>
Initially	O
developed	O
by	O
Halcrow	O
Group	O
and	O
then	O
CH2M	O
Hill	O
,	O
Flood	B-Application
Modeller	I-Application
is	O
now	O
developed	O
by	O
Jacobs	O
Engineering	O
group	O
.	O
</s>
<s>
Flood	B-Application
Modeller	I-Application
includes	O
steady-state	O
and	O
unsteady	O
1D	O
river	O
solvers	B-Application
for	O
modelling	O
open-channels	O
.	O
</s>
<s>
It	O
also	O
provides	O
a	O
1D	O
urban	O
solver	B-Application
for	O
modelling	O
urban	O
drainage	O
systems	O
.	O
</s>
<s>
Flood	B-Application
Modeller	I-Application
includes	O
three	O
different	O
2D	O
solvers	B-Application
:	O
</s>
<s>
The	O
ADI	O
solver	B-Application
is	O
based	O
on	O
the	O
DIVAST	O
numerical	O
engine	O
first	O
developed	O
in	O
the	O
1980s	O
,	O
and	O
is	O
designed	O
to	O
simulate	O
fluvial	O
,	O
overland	O
,	O
estuarine	O
and	O
coastal	O
situations	O
where	O
flow	O
does	O
not	O
rapidly	O
change	O
.	O
</s>
<s>
The	O
TVD	O
solver	B-Application
is	O
designed	O
to	O
represent	O
rapid	O
changes	O
in	O
the	O
water	O
surface	O
profile	O
,	O
but	O
results	O
in	O
longer	O
run-times	O
.	O
</s>
<s>
The	O
FAST	O
solver	B-Application
uses	O
simplified	O
hydraulics	O
to	O
perform	O
rapid	O
assessments	O
of	O
flooding	O
.	O
</s>
