HEC-RAS 3.0 
January, 2001
Release Notes


	A new version of HEC-RAS (3.0) has been released with significant 
new features over the previous version (2.21).  Version 3.0 includes 
unsteady flow routing capabilities, as well as several new features for steady 
flow water surface profile computations.  The following is a list of the new 
features that have been added:

A.	Unsteady Flow Routing Features

1.	Unsteady Flow Data Editor – This editor allows the user to 
enter boundary conditions and the initial state of the system.  
Boundary conditions consist of stage and flow hydrographs, 
rating curves, gate settings, etc…  See Chapter 8 "Performing 
an Unsteady Flow Analysis" for details.

2.	Unsteady Flow Simulation Manager – This simulation 
manager allows the user to set up an unsteady flow simulation.  
The user is required to define a plan, establish a time window, 
and select several other computational options. See Chapter 8 
"Performing an Unsteady Flow Analysis" for details.

3.	Geometric Pre-Processor (HTAB) – The geometric pre-
processor converts the geometry data into a series of tables and 
rating curves.  This is done in order to speed up the unsteady 
flow calculations.  Cross sections are converted to tables of 
elevation versus area, conveyance, and storage.  Bridges, 
culverts, and weirs are converted into a family of rating curves 
that describe headwater, tailwater, and flow rate. See Chapter 8 
"Performing an Unsteady Flow Analysis" for details.

4.	Output Post-Processor – The post-processor is used to 
calculate detailed hydraulic information for a set of user 
specified time lines during the unsteady flow simulation period.  
The post-processor takes the computed flows and stages from 
the unsteady flow model and calculates all of the hydraulic 
variables required for detailed output.  By running the post-
processor, the user will have all of the available plots and tables 
for unsteady flow that HEC-RAS normally produces for steady 
flow. See Chapter 8 "Performing an Unsteady Flow Analysis" 
for details.

5.	Stage and Flow Hydrograph Plots – We have added the 
ability to plot and tabulate both stage and flow hydrographs.  
The plot allows the user to plot just stage, just flow, or both.  
You can also plot observed data, if you have it in a HEC-DSS 
file.

6.	Graphics Animation – We have added the ability to animate 
the cross section, profile, and 3 dimensional graphics.  
Animation consists of stepping through the computed results 
based on a user specified output interval.  Try it out, its fun!!!

7.	UNET Data Importer – We have added the ability to import 
the geometry data from a UNET model (CSECT files).  This 
option is available from the File menu of the Geometric Data 
Editor.  At this time we have not added the ability to import 
UNET boundary condition files.  Sorry, maybe for the final 
Version 3.0.


B.	New Geometric Data Features – The following is a list of the new 
features that can be found in the Geometric Data Editor.  These 
features work for both unsteady flow and steady flow computations.

1.	Lateral weirs and gated spillways – Lateral weirs and gated 
spillways allow the user to remove flow from the main river 
through gated structures or uncontrolled over flow weirs.  
Lateral weirs and gated spillways can be connected to a storage 
area or another river reach.

2.	Lateral rating curves – This option allows the user to enter 
elevation vs. flow rating curve for flow leaving the main river.  
A lateral rating curve can be used to send flow to another reach 
or the flow can just leave the system without being connected to 
something else.

3.	Storage areas – Storage areas are used to define an area where 
water will pond (i.e. no significant conveyance in the 
downstream direction).  They are often used to model off 
channel storage or an area behind a levee.

4.	Hydraulic Connections – Hydraulic connections are used to 
pass flow between storage areas or between a storage area and 
another reach through the use of culverts and/or a weir.  
Hydraulic connections consist of a weir, culverts and a weir, or 
gated spillways and a weir.

5.	Cross Section Points Filter – This editor allows the user to 
reduce the number of points in a cross section by using a near 
point filter and a collinear line filter.  The near point filter 
allows the user to set a vertical and horizontal tolerance.  If two 
points are within both the vertical and horizontal tolerance, then 
the second point is removed.  A collinear line filter allows the 
user to enter a vertical distance tolerance and a slope tolerance.  
The program takes three points in a row, puts a straight line 
through the first and third, then checks to see the vertical 
distance between the line and the second point.  If the distance 
is less than a pre-defined value, and removing that point will 
not change the line slope more than a pre-defined amount, then 
the point is removed.

6.	CONSPAN Culvert Shape – We have added a new culvert 
shape called a CONSPAN culvert.  This culvert shape is a pre-
fabricated concrete culvert that has a natural bottom.  These 
culvert shape are very good for fish passage and other 
environmental factors.

7.	Buried Culverts – you can now specify a depth buried inside 
of any culvert.  This allows the user to model culverts that are 
buried on purpose, as well as culverts that have sediment 
deposits.

8.	Multiple Manning's n Values in Culverts – The user can now 
enter separate Manning's n values for the culvert bottom versus 
the culvert sides and top.
9.	Sediment Elevations – We have added the ability for the user 
to specify a depth of sediment in any cross section.  Sediment 
depths can be entered over a range of cross sections by 
projecting the sediment on a slope, or by specifying the depths 
at the two ends and interpolating in between.  

10.	Pilot Channels – This is a feature that is used in unsteady flow 
routing.  For reaches that have shallow flow and are 
experiencing stability problems.  A pilot channel can be added 
to increase the depth seen by the numerical solution, which 
intern improves stability of the solution. 

11.	Permanent Ineffective Flow Areas – this option allows the 
user to set an ineffective flow area to permanent.  This means 
the area will stay ineffective, even after the water surface rises 
above the top elevation of the ineffective flow.  This was 
mainly added for unsteady flow, but can also be used in steady 
flow.  For unsteady flow, some times when a large ineffective 
flow area goes from ineffective to completely effective, 
instabilities would occur in the solution.

12.	Bridge Skew – User can now enter skew angles for bridge 
decks/roadways and bridge piers, the HEC-RAS program will 
then adjust the bridge opening and pier widths accordingly.  
The cross sections that bound the bridge can also be adjusted 
automatically for skew.


C.	Split Flow Optimization

We have added the ability to perform split flow optimization in the 
steady flow water surface profile computation program.  This option 
allows for flow splits at junctions, as wells lateral weirs and gated 
spillways.  This is an option the user must turn on from the steady 
flow analysis window.  The user is required to enter an initial estimate 
of flows in all of the reaches, and then the program will optimize the 
split of flow through an iterative scheme of computing profiles and 
evaluating flow splits.  More information on this can be found in 
example 15 of the applications guide.  Example 15 was printed as 
supplemental documentation for Version 3.0 beta.

D.	HEC-GeoRAS

HEC-GeoRAS 3.0 is a new application for support of HEC-RAS 
using ArcView GIS.  GeoRAS allows engineers with limited 
geographic information systems (GIS) experience to develop 
geometric data for import into HEC-RAS and to process results 
exported from HEC-RAS.    You must have the ArcView GIS 3.1 
software with the 3D Analyst extension to use GeoRAS.  Included on 
the CD are the HEC-GeoRAS ArcView extension and users 
documentation.  See Chapter 2 of the GeoRAS User's Manual for 
installation instructions.


E.	Bug Fixes Since Version 2.21 (including bugs in the 3.0 beta 
version)

1.	XS Editor - The menu item for ice cover, once checked was staying checked for other XSs 
sometimes even when there is no ice cover information.

2. 	Graphical XS Editor.  There was a bug that crashed the application when users did the 
following:
	Add a normal ineffective area	
 	Add a blocked ineffective area
	Attempt to move the normal ineffective area

3. 	Steady Flow Data Editor - Last data entered in the grid text editing box was not saved.  The 
grid text editing box is activated by pressing F2 or double-clicked the mouse on the grid.  If 
the flow is changed and the window was closed, then the data for this one cell will not be 
saved.  The text editor can be used to edit data, but the user would have to change the focus 
to another cell before the data would be saved.  Note, this only happen if you double click or 
press F2.

4. 	DSS plots and tables with weekly time interval data might not have worked.

5. 	Printing Profile Tables - If the option to print gray headers is unchecked, the program did not 
print the variable headers at all.

6. 	Geo-referencing data is now converted when the project units are converted.

7. 	Right Levee elevations - When a right levee was entered without an elevation at the station of 
a vertical wall, the elevation would be computed at the bottom of the wall.  This has been 
changed to the top.

8. 	GIS Bounding Polygon - The bounding polygon did not recognize a levee at the start or end 
of a cross section as a constriction.

9. 	Pressing Delete in an empty plan or profile list caused program to crash.

10.	DSS Plots - Plot did not work for dates before 1900.

11.	Printing from the bridge and culvert editor with a user-defined scale did not work properly.

12. GIS Import - When the bank stations are set to 0,0 in the import file, RAS would duplicate the 
first point.

13. Plotting Culvert Rating Curves.  RAS used to get the invert from the first culvert in the output 
file, now it finds the culvert with the lowest invert.

14. Printing Multiple Culvert Tables.  RAS would only print the first culvert even if there were 
multiple culverts in the data.

15. Profile plot plan comparison.  An error occurred if the reaches did not have the same 
downstream river station.

16. Selecting a new printer - from the print dialog, users could select a different printer than the 
current, but the selection would not be used in printing.

17. Profile plots of ice though bridges - The upstream and downstream ice elevations were 
swapped on the plot (but not in computations).

18. Encroachments - A subscript out of range error occurred if there were more profiles in flow 
data than in the encroachment data.  For example the flow data could have 4 profiles, but the 
encroachment data only covers profile 2 and 3, this would cause the error.

19. Report Generator with Culverts of type: Semi-circle and high arch cause report generator to 
fail.

20. Importing a river reach from a HEC-RAS file and adding them to an existing system 
sometimes caused cross sections from other reaches to be added to the new reach.

21. Cross Section Interpolation - Could not interpolate with a distance less than 1 foot. (This has 
been there since the beginning).

22. Inundation Bounding Polygon had problems with culverts.    In particular culverts with weir 
flow that is not directly over the culvert barrels.

23. Connecting reaches to storage areas as an upstream boundary condition caused the reach 
line to be deleted.

24. Culvert Specific Output Table - Lists the culvert control criteria "inlet" or "outlet".  There was a 
bug added in the first 3.0 beta version.

25. DSS Project Specific Text was not getting reset to blank when loading another project.  This 
caused the first text entered to perpetuate into all subsequent projects.

26. DSS Viewer - The "Plot Selected Pathname(s)" button was modified to "Plot/Tabulate 
Selected Pathname(s)" to reflect the changes in 3.0 that plot and tabulate two tabs in one 
window.

27. Unsteady Post Process did a split flow optimization.  If a plan was a steady flow plan with split 
flow optimization and it was converted to an unsteady plan then it would perform the 
optimization on post process.  This has been changed to not perform the split flow 
optimization.

38. Lateral Weir Flow Computation Criteria - The program did not save the option, so it always 
defaulted back to using the water surface as the for reference weir flow computations.

39. Scour Computations - The contraction scour widths W1 and W2 used to use the full top 
widths, but were changed to use the active top widths to exclude the ineffective flow areas.

30. Scour Computations - The computation of abutment scour requires an abutment projection 
length L'.  This parameter used to be computed as the difference from the abutment toe 
station and the water surface intersection with the ground in the cross section immediately 
upstream of the bridge.  Now it is computed as width of the active flow area in the approach 
section that is used to compute Qa and Ae.  In addition the active width that was used to 
compute Ya, there was an error in computing that would over estimate the active width, 
possibly as much as one velocity subsection width.

31. River Mile locations in the DSS Plot Table were displayed to only 2 decimals. If the units are 
"MILES" then RAS displays this column with 3 decimals

32. DSS View form displays the path and file of the current DSS file.  This field was fixed in width 
and would not display a long path name.  The dropdown combo box now expands to fit the 
available width of the window.

33. Flow Stage Plotter for unsteady flow.  In original Beta 3.0, RAS did not compare plans in this 
viewer.

34. More lines are available in the errors warning and notes list on the cross section output table.

35. Renumbering the river station table asked users if they wanted to copy the existing RS to the 
cross sections description the first time that cross sections were renumbered, but not on 
subsequent reaches.

36. DSS Viewer - If the window was opened and minimized and the user pressed the DSS Viewer 
button on the main RAS form the window did not get maximized.  This left the user wondering 
where the DSS Viewer was at, and why the button appeared to not function.

37. Summary of Errors warnings and notes were incorrect and arbitrary for culverts.

38. An additional check was added to pre-computations for culverts, which makes sure the 
distance above a culvert barrel + barrel length is not greater than the distance between 
bounding cross sections.

39. The check box for equal conveyance reduction for encroachments did not work.  The program 
would always go to equal conveyance calculations.

40. Closing the Lateral weir editor when the lateral gate or lateral deck editors where open would 
cause the program to crash.

41. Storage areas can now be moved graphically as a unit on the geometric schematic editor, 
rather than at one point at a time.

42. When attempting to enter cross section data before a river station has been entered on the 
cross section editor, a message box appears informing the user that the River, Reach and 
RS must be set.  There was a bug in that the message would appear twice, if the user was 
trying to enter station elevation data.

43. Pressing the Help button the Culvert Editor caused the program to crash.

44. The photo viewer was modified so that it does not distort photos when in the stretching mode.

45. There was an error saving multiple type of boundary conditions in steady flow with certain 
arrangements of multiple reach systems.

46. The river reach line on the schematic editor did not show up when there were more then 
~10,000 points on the windows 9x versions.

47. There was a problem with encroachments after a river was deleted from the geometry.








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