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HECHEC--RASRASversion 3.0.1version 3.0.1

HEC-RAS Download files:

HECHEC--RAS download filesRAS download files

Version 3.0.1 needed for ice jamsVersion 3.0.1 needed for ice jams

User's ManualUser's Manual

Hydraulic Reference ManualHydraulic Reference Manual

Applications GuideApplications Guide

Please note:Please note: these files, and future updates of the program andthese files, and future updates of the program and

documentation, can be freely downloaded from the HEC website:documentation, can be freely downloaded from the HEC website:

http://www.hec.usace.army.mil/software/software_distrib/hechttp://www.hec.usace.army.mil/software/software_distrib/hec--ras/hecrasprogram.htmlras/hecrasprogram.html

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HEC-RAS Documentation:

UserUsers Manuals Manual for the beginnerfor the beginnerhow to get startedhow to get started

details of how to use HECdetails of how to use HEC--RAS (input, output, running)RAS (input, output, running)

Hydraulic Reference ManualHydraulic Reference Manual details of the equations, theories, assumptions, methodsdetails of the equations, theories, assumptions, methods

advice on how best to use HECadvice on how best to use HEC--RASRAS

details on differences between HECdetails on differences between HEC--RAS and HECRAS and HEC--22

Applications GuideApplications Guide example applications, stepexample applications, step--byby--stepstep

Introduction to HECIntroduction to HEC--RASRAS

Overview of HECOverview of HEC--RASRAS

Interface and output featuresInterface and output features

Modelling Ice CoversModelling Ice Covers

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HEC RAS Version 3.0.1HEC RAS Version 3.0.1 (March 2001)(March 2001)

11

--D steady GVF calculationsD steady GVF calculations

Open waterOpen water

Simple ice coverSimple ice cover

Ice jamIce jam

11--D unsteady GVF calculationsD unsteady GVF calculations

SubcriticalSubcritical flow onlyflow only

Sediment AnalysisSediment Analysis

Bridge scour (contraction and pier scour)Bridge scour (contraction and pier scour)

HECHEC--6 type6 type calcscalcs (coming later)(coming later)

11--D Steady Flow CalculationD Steady Flow Calculation

Flow regimesFlow regimes

SubcriticalSubcritical

SupercriticalSupercritical

MixedMixed

Basic solution procedureBasic solution procedureBased on the energy equationBased on the energy equation

Momentum equation used for special casesMomentum equation used for special cases

(e.g. RVF, mixed flow regimes, confluences,(e.g. RVF, mixed flow regimes, confluences,

bridges, hydraulic jumps)bridges, hydraulic jumps)

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Energy Equation

e

2

111

2

222 h

2g

VWS

2g

VWS ++=+

WSWS11 && WSWS22 = water surface elevations (= water surface elevations (WSWS == ZZ ++ YY))

VV11 && VV22 = average velocities= average velocities

11 && 22 = kinetic energy correction coefficients= kinetic energy correction coefficientsgg = gravitational acceleration= gravitational acceleration

hhee = head loss (due to friction & transitions)= head loss (due to friction & transitions)

HECHEC--RAS uses the Standard Step method proceeding inRAS uses the Standard Step method proceeding in

either the upstream direction (either the upstream direction (subcriticalsubcritical flow) or theflow) or the

downstream direction (supercritical flow).downstream direction (supercritical flow).

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Energy Losses

)2gV

2gVC(LSh

211222fe +=

LL = discharge weighted reach length= discharge weighted reach length

SSff= friction slope, averaged between the two= friction slope, averaged between the two

sectionssections

CC= contraction or expansion loss coefficient= contraction or expansion loss coefficient

Friction Slope,Friction Slope, SSff(Mannings Equation)(Mannings Equation)

2/13/21fSAR

nQ =

QQ = discharge for the section= discharge for the section

nn = Mannings resistance coefficient= Mannings resistance coefficient

AA = flow area= flow area

RR = hydraulic radius= hydraulic radius

SSff = friction slope= friction slope

S.I. version

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Introduction to HECIntroduction to HEC--RASRAS

Overview of HECOverview of HEC--RASRAS Interface and output featuresInterface and output features

Modelling Ice CoversModelling Ice Covers

To start the program,

double click on theHEC-RAS icon

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This opens HEC-RAS main window

HEC-RAS works with projects.

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Elements of a Project

Project File: filename.prj

Geometry Data

filename.g01

Steady Flow Data

filename.f01

Geometry Data

filename.g02

Plan 1

filename.p01

Plan 2

filename.p02

Run File 1

filename.r01

Run File 2

filename.r02

Output File 1

filename.o01

Output File 2

filename.o02

Geometry Data

Geometry data can beGeometry data can be

imported from bothimported from both

HECHEC--RASRAS ororHECHEC--22

file formats.file formats.

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Reach Layout Drawing

1. Add river1. Add river

reaches alongreaches along

with anywith any

junctions.junctions.

Use the reachUse the reach

drawing tool anddrawing tool and

double click todouble click to

end a reach.end a reach.

2. Add cross2. Add cross--

section names,section names,

elevationelevation--

station data,station data,

nn values, bankvalues, bankstations, reachstations, reach

lengths, losslengths, loss

coefficients,coefficients,

etc.etc.

Additional Geometry Data

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3. Add road,3. Add road,

bridge orbridge or

culvert dataculvert data

and/orand/or

weir orweir or

spillwayspillway

data.data.

Additional Geometry Data

View your cross section data...View your cross section data...

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Specifying the Flow Data

The most upstreamThe most upstream

cross section willcross section will

appear in the first row.appear in the first row.

Additional flowAdditional flow

change locations canchange locations canbe added at other crossbe added at other cross

sections within thesections within the

reach.reach.

Boundary Conditions

4 options

Choose a known water surface

elevation at d/s boundary.

Choose normal depth by providing the

assumed slope of the energy grade line.

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Steady Flow Computation

Then simply press compute!Then simply press compute!

Error messages will appear if there isError messages will appear if there is

inadequate geometry or flow information.inadequate geometry or flow information.

Viewing Results - Tabular

HEC-RAS provides

you with a variety of

default tables.

You can customize

and then save your

own table formats!

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Viewing Results - Graphical

Note observed water surface profileNote observed water surface profile -- used for calibration.used for calibration.

Adding an Observed Water Surface Profile

Select the river station from the pull down menu as illustrated

Then click on the Add an Obs. WS Location button.

Enter the observed water surface elevation for the station and

repeat the process (adding new stations for each water level) until

you have a complete observed water surface profile.

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Using tabular input for adjusting channel properties.

Highlight a group of cells for

the river stations of interest.

Make global changes to those cells (e.g. set them all to the same value).

Introduction to HECIntroduction to HEC--RASRAS

Overview of HECOverview of HEC--RASRAS

Interface and output featuresInterface and output features

Modelling Ice CoversModelling Ice Covers

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Modelling Ice Covers:

HECHEC--RASRAS has the ability to model simplehas the ability to model simple

ice covers and ice jams. (only version 3.0.1ice covers and ice jams. (only version 3.0.1

can model ice jams).can model ice jams).

Details of the various ice modelling methodsDetails of the various ice modelling methods

are covered in Chapter 11 of the Hydraulicare covered in Chapter 11 of the Hydraulic

Reference Manual.Reference Manual.

Details of how to enter ice data, how toDetails of how to enter ice data, how to

perform ice cover calculations, and how toperform ice cover calculations, and how toview ice profile results, are provided inview ice profile results, are provided in

Chapter 6 of the UserChapter 6 of the Users Manual.s Manual.

A simple ice cover is a continuous ice cover ofA simple ice cover is a continuous ice cover of

known thickness and roughness.known thickness and roughness.

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Clearwater River

(photo courtesy of Larry Garner, Alberta Environment)(photo courtesy of Larry Garner, Alberta Environment)

Ice JamIce Jam calcscalcs. solve for accumulation thickness. solve for accumulation thickness

Clearwater River

(photo courtesy of Larry Garner, Alberta Environment)(photo courtesy of Larry Garner, Alberta Environment)

Ice Jam TextureIce Jam Texture