<s>
HEC-RAS	B-Application
is	O
simulation	B-Application
software	I-Application
used	O
in	O
computational	O
fluid	O
dynamics	O
–	O
specifically	O
,	O
to	O
model	O
the	O
hydraulics	O
of	O
water	O
flow	O
through	O
natural	O
rivers	O
and	O
other	O
channels	O
.	O
</s>
<s>
The	O
basic	O
computational	O
procedure	O
of	O
HEC-RAS	B-Application
for	O
steady	O
flow	O
is	O
based	O
on	O
the	O
solution	O
of	O
the	O
one-dimensional	O
energy	O
equation	O
.	O
</s>
<s>
For	O
unsteady	O
flow	O
,	O
HEC-RAS	B-Application
solves	O
the	O
full	O
,	O
dynamic	O
,	O
1-D	O
Saint	O
Venant	O
Equation	O
using	O
an	O
implicit	O
,	O
finite	O
difference	O
method	O
.	O
</s>
<s>
HEC-RAS	B-Application
is	O
equipped	O
to	O
model	O
a	O
network	O
of	O
channels	O
,	O
a	O
dendritic	O
system	O
or	O
a	O
single	O
river	O
reach	O
.	O
</s>
<s>
Certain	O
simplifications	O
must	O
be	O
made	O
in	O
order	O
to	O
model	O
some	O
complex	O
flow	O
situations	O
using	O
the	O
HEC-RAS	B-Application
one-dimensional	O
approach	O
.	O
</s>
<s>
HEC-RAS	B-Application
is	O
a	O
computer	O
program	O
for	O
modeling	O
water	O
flowing	O
through	O
systems	O
of	O
open	O
channels	O
and	O
computing	O
water	O
surface	O
profiles	O
.	O
</s>
<s>
HEC-RAS	B-Application
finds	O
particular	O
commercial	O
application	O
in	O
floodplain	O
management	O
and	O
[	O
flood	O
insurance ]	O
studies	O
to	O
evaluate	O
floodway	O
encroachments	O
.	O
</s>
<s>
HEC-RAS	B-Application
has	O
merits	O
,	O
notably	O
its	O
support	O
by	O
the	O
US	O
Army	O
Corps	O
of	O
Engineers	O
,	O
the	O
future	O
enhancements	O
in	O
progress	O
,	O
and	O
its	O
acceptance	O
by	O
many	O
government	O
agencies	O
and	O
private	O
firms	O
.	O
</s>
<s>
It	O
is	O
often	O
possible	O
to	O
use	O
HEC-RAS	B-Application
to	O
overcome	O
instability	O
issues	O
on	O
river	O
problems	O
.	O
</s>
<s>
The	O
first	O
version	O
of	O
HEC-RAS	B-Application
was	O
released	O
in	O
1995	O
.	O
</s>
<s>
This	O
HEC-RAS	B-Application
1.0	O
solves	O
the	O
same	O
numerical	O
equation	O
of	O
the	O
1968	O
HEC-2	O
.	O
</s>
<s>
GeoHECRAS	O
is	O
a	O
2D/3D	O
visualization	O
and	O
editing	O
data	O
wrapper	O
to	O
the	O
HEC-RAS	B-Application
software	O
and	O
used	O
for	O
flood	O
control	O
and	O
flood	O
mitigation	O
engineering	O
studies	O
,	O
including	O
production	O
of	O
Federal	O
Emergency	O
Management	O
Agency	O
flood	O
hazard	O
maps	O
and	O
other	O
river	O
engineering	O
studies	O
.	O
</s>
<s>
Features	O
related	O
to	O
HEC-RAS	B-Application
include	O
:	O
</s>
<s>
WMS	B-Application
(	O
watershed	B-Application
modeling	I-Application
system	I-Application
)	O
is	O
a	O
hydrology	O
software	O
that	O
provides	O
pre	O
and	O
post-processing	O
tools	O
for	O
use	O
with	O
HEC-RAS	B-Application
.	O
</s>
<s>
The	O
development	O
of	O
WMS	B-Application
by	O
Aquaveo	O
was	O
funded	O
primarily	O
by	O
The	O
United	O
States	O
Army	O
Corps	O
of	O
Engineers	O
.	O
</s>
<s>
Features	O
related	O
to	O
HEC-RAS	B-Application
include	O
:	O
</s>
<s>
Using	O
feature	O
objects	O
(	O
centerline	O
,	O
cross	O
section	O
lines	O
)	O
and	O
a	O
TIN	O
to	O
develop	O
the	O
geometry	O
of	O
a	O
HEC-RAS	B-Application
model	O
.	O
</s>
<s>
Editing	O
,	O
merging	O
,	O
and	O
creating	O
cross	O
sections	O
in	O
a	O
database	O
for	O
use	O
with	O
HEC-RAS	B-Application
and	O
other	O
hydraulic	O
models	O
.	O
</s>
<s>
Water	O
surface	O
elevations	O
can	O
be	O
computed	O
by	O
HEC-RAS	B-Application
,	O
defined	O
interactively	O
,	O
or	O
imported	O
from	O
a	O
file	O
.	O
</s>
<s>
Linking	O
multiple	O
simulations	O
of	O
HEC-1	O
to	O
HEC-RAS	B-Application
to	O
determine	O
the	O
uncertainty	O
in	O
modeling	O
parameters	O
on	O
a	O
delineated	O
flood	O
plain	O
.	O
</s>
<s>
Curve	O
Number	O
and	O
Precipitation	O
can	O
be	O
stochastically	O
varied	O
among	O
HEC-1	O
parameters	O
and	O
Manning	O
's	O
n	O
value	O
for	O
HEC-RAS	B-Application
.	O
</s>
