Quick Reference

Fast lookup tables for common HEC-RAS keywords, paths, and formats.

Geometry File Keywords

Cross Section Keywords

Keyword	Description	Example
River Reach=	Start of river/reach block	River Reach=River1,Reach1
Type RM Length L Ch R =	Cross section header	Type RM Length L Ch R = 1 ,1000,500,500,500
#Sta/Elev=	Station-elevation pairs count	#Sta/Elev= 40
#Mann=	Manning's n segments	#Mann= 3 , 0 , 0
Bank Sta=	Bank station locations	Bank Sta=190,375
XS GIS Cut Line=	Cross section GIS coordinates	XS GIS Cut Line= 5
Levee=	Levee data	Levee= 12 , 0
Ineffective=	Ineffective flow areas	Ineffective= 2 , 0 , 0
Blocked=	Blocked obstruction	Blocked= 2 , 0

2D Flow Area Keywords

Keyword	Description
Storage Area=	Storage area definition
2D Flow Area=	2D mesh area definition
Storage Area Conn=	SA/2D connection
Connection=	Generic connection
BC Line Name=	Boundary condition line

Structure Keywords

Keyword	Description
Type RM Length L Ch R = 2	Bridge
Type RM Length L Ch R = 3	Inline weir
Culvert=	Culvert definition
Lateral Weir=	Lateral structure
Inline Structure=	Inline structure

Plan File Keywords

Keyword	Description	Example
Plan Title=	Plan name	Plan Title=Base Run
Short Identifier=	Short ID	Short Identifier=p01
Geom File=	Geometry reference	Geom File=g01
Flow File=	Flow file reference	Flow File=u01
Run HTab=	Run hydraulic tables flag	Run HTab= -1
Run UNet=	Run unsteady flag	Run UNet= -1
Run PostProcess=	Run RASMapper flag	Run PostProcess= 0
Computation Interval=	Time step	Computation Interval=2MIN
Output Interval=	Output frequency	Output Interval=15MIN
UNET D1 Cores=	1D cores	UNET D1 Cores= 1
UNET D2 Cores=	2D cores	UNET D2 Cores= 4

HDF Path Quick Reference

Most Common Paths

Python

# Plan Info
"/Plan Data/Plan Information"

# 2D Max Results
"/Results/Unsteady/Output/Output Blocks/Base Output/Summary Output/2D Flow Areas/{area}/Maximum Water Surface"

# 2D Time Series
"/Results/Unsteady/Output/Output Blocks/Base Output/Unsteady Time Series/2D Flow Areas/{area}/Water Surface"

# 1D Cross Section Results
"/Results/Unsteady/Output/Output Blocks/Base Output/Unsteady Time Series/Cross Sections/{river}_{reach}/Water Surface"

# Timestamps
"/Results/Unsteady/Output/Output Blocks/Base Output/Unsteady Time Series/Time Date Stamp"

# Mesh Geometry
"/Geometry/2D Flow Areas/{area}/Cells Center Coordinate"

# Steady Results
"/Results/Steady/Output/Geometry/Cross Sections/{river}_{reach}/Water Surface"

Path Variables

Variable	Description	Example
{area}	2D flow area name	"Floodplain"
{river}	River name	"White River"
{reach}	Reach name	"Upper"
{river}_{reach}	Combined (spaces removed)	"WhiteRiver_Upper"

Data Format Cheat Sheet

Fixed-Width Columns

Data Type	Width	Per Line	Example
1D Sta/Elev	8 chars	10 values	0 660.41
2D Coordinates	16 chars	4 values	648224.43125
Manning's n	8 chars	9 values (3 triplets)	0 .06 0

Count Interpretation

Keyword	Count Means	Total Values
#Sta/Elev=	PAIRS	count × 2
#Mann=	SEGMENTS	count × 3
Reach XY=	PAIRS	count × 2
Storage Area Surface Line=	POINTS	count × 2
Levee=	TOTAL values	count

Time Formats

Source	Format	Example
HDF timestamp	%d%b%Y %H:%M:%S:%f	01JAN2000 00:00:00:000
COM timestamp	%d%b%Y %H%M	01JAN2000 0000
Plan file	ddMMMYYYY,HHMM	01Jan2000,0000

Computation Interval Strings

String	Interval
1SEC	1 second
2SEC	2 seconds
5SEC	5 seconds
10SEC	10 seconds
15SEC	15 seconds
30SEC	30 seconds
1MIN	1 minute
2MIN	2 minutes
5MIN	5 minutes
10MIN	10 minutes
15MIN	15 minutes
30MIN	30 minutes
1HOUR	1 hour

Culvert Shape Codes

Code	Shape
1	Circular
2	Box
3	Pipe Arch
4	Ellipse
5	Arch
6	Semi-Circle
7	Low Profile Arch
8	High Profile Arch
9	Con Span

Run Flag Values

Value	Meaning
-1	True/Enabled
0	False/Disabled

RASMapper Inversion

Run PostProcess= uses inverted logic: 0 = True, -1 = False

See Also

• Geometry Parsing - Detailed parsing reference
• HDF Structure - Complete HDF documentation
• File Formats - File naming conventions