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Up ] Move MIDUSS ] [ 98 Build update ]

MIDUSS 98 Build and Update

MIDUSS has been under development since 1981 and we are continually making improvements.  The first version was used on DOS systems and progressed to version 4.72.1.  The software was completely rewritten for the Windows operating system and on Sept. 4, 1998 MIDUSS 98 version 1.0 was released.  The final update to MIDUSS 98 was released May 4, 2004.  We are no longer developing updates for this version.

For MIDUSS 98 we used an update DATE as the version indicator. 

Compared to the Sept. 4, 1998 (the original MIDUSS on the 1998 CD media) and subsequent updates since then, the current downloadable version has the following changes. 

Number of updates released:
1998: 1
1999: 31
2000: 13
2001: 24
2002: 13
2003: 9
2004: 1

To find out your current version while running MIDUSS, click the Help / About menu item.

The final version is: MIDUSS 98 - version 1.0 - May 5, 2004.

The MIDUSS 98 Demo is no longer available.


Latest MIDUSS 98 Update:

The link below lets you download the final May 5, 2004 update.

Download 1.8 MB

The main executable is the only file that needs to be updated.  The executable is named Miduss98.exe and is contained in a self expanding file that is named 'm98v100FS.exe'.   You will download the m98v100FS.exe file, double click it, and it will self expand into Miduss98.exe.

You update your MIDUSS 98 follow these steps:

  1. Download the file to the \Miduss98\ folder or directory. 

  2. Navigate to the \Miduss98\ folder and locate the 'm98v100FS.exe'. Double-click on this file.

  3. It will expand to create the larger file Miduss98.exe.  You will see a warning that a file of the same name will be overwritten.  This is OK so click on [Extract].  

MIDUSS98 Users

If you require the final release of the setup program for MIDUSS98 you can download it here.  This downloads the program used to install Miduss98 on your PC. 

Note: MIDUSS98 will co-exist on the same PC as our new MIDUSS Version 2.  There is no interference.

Download now
Oct. 10, 2003.    10.5MB

Once installed you should update the main executable program by downloading the May 5, 2004 update discussed in the section above.


May 5, 2004
  • During use of the automatic mode there was an error importing data to the stage discharge table in the pond and trench commands. This has been corrected.
Oct. 10, 2003
  • A change has been made to the Log form that appears during the various Design features. Previously, when very long strings of text were added to the log list, code to increase the width of the form resulted in multiple errors being reported by the FailSafe system. This has been corrected.
Sept. 28, 2003
  • The August 13 update had an error that prevented certain user options from being recalled on startup.
    This has been corrected.
Aug. 13, 2003
  • Unfortunately, the ‘improvement’ in the Storm and Catchment command of Aug.3 failed for non-Malaysian users when the new Value Key for the Storm and other options had not yet been created. This has been corrected.
Aug 3, 2003
  • The Storm and Catchment commands have been improved so that user-selected options for storm type, overland routing, length option and infiltration option are stored in the Registry and become the default values for future runs until subsequently changed. For Malaysian users, the Storms (Malaysia) menu item is automatically selected.
July 31, 2003
  • The Pond command has been modified to enable routing when all data for WL, Q and Volume has been entered by hand into the HQV grid rather than by use of the Geometry or Outflow Control tools.
  • In the Pond command the tool to compute the equivalent rectangular aspect ratio as a function of user defined values of area and perimeter has had some cosmetic changes to correct text labels.
June 17, 2003
  • In the Pond command an error can occur if one or more weirs are defined but the vector of water levels does not contain a value acceptably close to the weir crest level. This is often caused by using a small number of stages (e.g. less than 10). This has been corrected by warning the user if this situation occurs and prompting a manual edit of the closest water level to match the weir invert level.
  • The Trench command has been modified to allow a zero value for the gradient. This is useful when modelling an infiltration basin which is approximated by a very wide channel with flat side-slopes and a ‘Voids Ratio’ of 100%.
  • In the Pond command the [Route] button was not enabled if values of H and V were entered directly into the grid followed by use of the Outflow Control command to define the Q values. This has now been corrected.
  • Minor changes were made to ensure compatibility with controls delivered with Windows XP.
March 27, 2003
  • An error introduced in the Mar. 12, 2003 version update caused the pipe parameters to not be updated properly when running in Automatic mode.  This has been corrected.
March 12, 2003
  • A number of minor fixes have been made to both the Miduss98.exe program and the Setup.exe files to correct problems with installation and running under Windows NT4, 2000 and XP.
  • In the Pipe command feasible values of Diameter and Grade are shown automatically but can be edited as before or selected from the table of diameters and grades simply by double clicking on a row.
  • Some minor changes have been made to detect use of Windows XP and make minor adjustments to dimensions of forms and default positions of the mouse pointer.
  • The Hydrology/Baseflow command now includes the option to use a negative value of baseflow.
  • In the Hydrology/Lag & Route command an error in the calculation of the routed hydrograph has been corrected.
December 4, 2002

·         A minor error has been fixed in the Trench command concerning the adjusting of the stage-volume data to allow for either perforated or non-perforated pipes within the clear stone fill.  Previously this occasionally caused the curve of volume as a function of depth to be non-monotonic.

·         In the Hydrograph/Combine command the code has been modified so that in Automatic mode the user can manually define a Junction node prior to the point in the Input database at which the same Junction node is introduced.  Subsequent uses of Combine with reference to that Junction node cause flows to be accumulated in the normal way.

·         In the Hydrology/Storm command the Canadian AES option gave an error if the storm duration was less than or equal to the time to peak.  This error is now properly trapped and corrected.

·         In the Hydrology/Lag and Route command, any change made to the values of channel or reservoir lag did not cause the [Accept] button to be disabled (grayed out).  This has now been corrected thus forcing the user to press the [Route] button to update the result before accepting the result.


November 8, 2002

·         In the Channel command the format of the value of Manning’s ‘n’ has been changed to show 3 decimal figures.  This corrects a problem in which a value of (say) n = 0.036 used in Manual mode was read in Automatic mode as n = 0.04 with resultant change in the computed design results.

October 22, 2002

·         When using the Show/Output File command MIDUSS uses Wordpad.exe if the Output File is larger than 50 KB.  If Wordpad.exe is not found either by the program or by the user the Show/Output File is cancelled.  Previously this sometimes caused the Output File to be closed which effectively terminated the session.  This problem has now been corrected

October 21, 2002
  • Correction made in the Form that displays graphics to update status of the window.
  • When running in Manual mode use of the Hydrograph/Undo command is sometimes necessary to correct an error. This is saved in the Output file. Code has been changed in the routine that converts an Output file to database Miduss.Mdb so that if the ‘HYDROGRAPH Undo’ record is encountered the user is warned of the location and advised to check if use of ‘Undo’ is still appropriate in a subsequent run in Automatic mode.
  • Code in the graphic display module has been corrected to avoid an error resulting in a “Log of zero variable” warning that occurred in certain rare circumstances.
  • In graphic displays the user selected time window for a hydrograph is now saved as the default for the next hydrograph graphic display. Also, the selected time window in the graphic display is now properly rounded down to the nearest 50 or 100 minutes instead of the nearest time increment.
  • In the Hydrology/Lag & Route command the user choices for ‘Show Options’ and ‘Set Lags Explicitly’ are now retained as defaults for the next use of the command.
September 11, 2002
  • A display error in the Lag & Route command has been fixed. When the lag & route operation is carried out the modified Runoff hydrograph is displayed in a table. This table contains a spin button to change the number of decimal places used. Unfortunately, in this command use of the spin button caused a different hydrograph to be displayed. The graph display and the computed (and saved) result was unaffected.
  • In the Trench command the user can define the diameter of the upstream manhole access shaft. This affects the stage-volume curve and in certain cases may help to avoid numerical instabilities. The command has been modified so that a finite value is initially displayed as the default. Previously, the default was zero.
  • When an existing output file is processed to create the input database Miduss.Mdb the path of the old file was sometimes truncated if very long. This has been corrected.
March 30, 2002
  • Two problems corrected concerning the use of the Hydrograph/Undo command immediately after the Hydrograph/Combine command and after the Hydrograph/Confluence command.
  • After the Combine command the Undo command now correctly updates the junction file.
  • After the Confluence command the Undo command now writes the appropriate code to the Output file.
March 27,2002
  • The Show/Output File command has been further corrected to display large Output files in Wordpad when the Output file resides in a folder which has a path with one or more spaces.
March 24, 2002
  • The command Show/Output File uses either Notepad or Wordpad to display the output file. Users have reported that Wordpad sometimes reports a file sharing error. This has been corrected.
March 17,2002
  • In the Edit Inflow command the user is prompted to provide a brief description of the modified hydrograph when it is Accepted and saved. An error has been corrected which prevented this new description from being included in the header of the file.
March 01, 2002
  • On October 30, 2001 an improvement to the Pond command was added which automatically extended the range of depth was added. The messages associated with this feature have been improved to advise the user how to reject this automatic procedure if required.
February 19, 2002
  • In the POND command the superpipe storage device may be surcharged under extreme peak inflows. Previously this resulted in a vertical segment in the volume-stage curve which resulted in incorrect solutions. The calculation of volume has been modified to add to the volume the contribution of an upstream MH (1.2 m or 4 ft diam.) for each superpipe when the water level is higher than the upstream obvert level. This has improved the solution. Problem identified by Gustavo Jacome, R.V.Anderson Ltd.
February 18, 2002
  • In the Catchment command the SCS Curve Number option for rainfall loss estimation uses the parameters of Curve Number (CN), Runoff coeff. (C), Initial abstraction to potential Storage (Ia/S) and Initial abstraction depth (Ia). These are interdependent and changing any one will alter one or more of the other three. A coding error which made it difficult to explicitly define Ia has been corrected.
    If an unusual value is entered for any of the Catchment parameters a warning message alerts the user to a possible error. The message text gave a wrong description when metric (SI) units were used and this has now been corrected.
  • The calculation of the runoff hydrograph remains unchanged and involves the summation of the direct runoff from pervious and impervious fractions of the catchment area.
January 19, 2002
  • In the POND command if the user checks the ‘Keep all design data’ checkbox the [Route] button is enabled and the Peak Outflow is set to a blank when POND is used for a second time in the same design session.
  • When running in Automatic mode, the Combine command now shows the [New] button as enabled in order to let the user add a new junction without having to revert to Manual mode and then re-invoke Automatic mode.
December 17, 2001
  • A number of changes have been made to the messages displayed when transferring a license to another computer in order to prevent users from making errors in this process.
December 13, 2001
  • Corrections have been made to the commands for Automatic design of Pipes and Channels which are surcharged.
December 4, 2001
  • The logic and informational messages for the design of surcharged pipes and overtopped channels has been improved to clarify the various steps for both Manual and Automatic processing. Where possible the mouse pointer is automatically positioned on the response buttons of message boxes to speed processing in Automatic mode. These changes are an improvement on the update of November 19.
December 1, 2001
  • The change reported on November 25 has been modified. After creating or editing an Inflow hydrograph the user presses the [Accept] button and is forced to save the hydrograph as a file by specifying a filename in a Common Dialogue box. In addition, the user can enter a brief description of the file which forms part of the file header. Records are written to the Output file containing the description, filename, peak flow, duration and volume. In Automatic mode this information allows the file to be retrieved and loaded into the Inflow hydrograph if the user wishes to do so.
November 25, 2001
  • When the ‘Hydrograph/Create/Edit Inflow hydrograph’ command is used the new hydrograph is not automatically saved (see Help file). The [Accept] button has been modified to check if the user has saved the hydrograph as a file. If not already saved a warning message is displayed and an opportunity is given to open and use the ‘Hydrograph/FileI_O’ command.
November 19, 2001
  • When using the ‘Design/Pipe’ command in Automatic mode the program logic and warning messages have been improved to assist the user in handling the case of a surcharged pipe. Appropriate action is taken depending on the use or absence of the Diversion command in the Input database file. Similarly, the program checks for the use of the ‘Hydrograph/Next Link’ command after the Diversion command before using the Route command.
  • Corresponding changes have been made for using MIDUSS in Manual mode.
November 15, 2001
  • When processing a complex Channel cross-section in Automatic mode, the vertical and horizontal scales are now given more reasonable values to display the cross-section.
November 9, 2001
  • The Trench command has been improved to indicate surcharged conditions by regular Message boxes instead of the "red box" in the Trench window.
  • An error occurs in the Catchment command if the storm duration is less than three times the time step. This condition is checked and if detected the user is advised to reduce the time step. The error is normally handled well by the FailSafe version of MIDUSS.
November 6, 2001
  • The Hydrograph Menu has been modified to show the commands ‘Start New Tributary’ and ‘Create/Edit Inflow hydrograph’ instead of having these below the ‘Start’ menu.
  • The ‘Create/Edit Inflow hydrograph’ command has been modified to compute the Inflow volume. Previously this was undefined and caused an error if the Design/Pond command was attempted with the new Inflow hydrograph.
November 4, 2001
  • The use of the Channel and Pipe commands in Automatic mode has been modified to ensure that a false "surcharged/overtopped" error is not displayed when the inflow is increased significantly between successive uses of the Channel or Pipe command in the input database. This was caused by the Channel or Pipe window being displayed before all of the relevant data had been read from the input database Miduss.Mdb.
November 1, 2001
  • The command Hydrograph/FileI_O was modified to correct an error when writing a hydrograph to a file. Previously, the list of elements was repeated making the file twice as long as required. No numerical error was caused because only the first set of records was processed when the file was imported.
October 30,2001
  • The Design/Pond command has been improved to automatically extend the range (i.e. increase the maximum water level) in order to process the Inflow hydrograph. Error reporting if zero elements or non-monotonic functions are detected now uses regular Message boxes instead of the "red box" message in the Pond window. The Trench command has been similarly modified.
October 10,2001
  • In the AuthorizationInfo and Authorization windows the ‘What’s This’ Help did not work properly. This feature has therefore been disabled and the Authorization form is now directly linked to the regular Help file. A short Help file has also been added to the form describing the steps for transferring a license from one computer to another.
  • Appendix ‘B’ in the Help file has been completely re-written with many more illustrations. The topics have been expanded to cover Installation and Licensing of MIDUSS plus the license transfer procedure.
  • The messages displayed in the license transfer process have been improved.
September 23, 2001
  • A correction has been made to the Show/Restore Peak Flow Table which was not operating correctly in recent versions.
  • The File/Output File manu item has been changed so that the secondary menu items Create New File and Open Existing file have been deleted and combined into the single File/Open Output file command. The functionality has not changed but since the ‘Create New file’ and ‘Open Exiting file’ performed the same operation confusion over these items is now avoided.
  • In the Automatic Control Panel the [CLOSE] button is now disabled until an EXIT command has been read and processed in the input database Miduss.Mdb. This avoids an error condition encountered by attempting to close the file prematurely. More importantly, it is now possible to [SKIP] forward to and process the EXIT command and then press the [CLOSE] button following which a new input database file Miduss.Mdb can be created and opened to continue the run in Automatic mode. This allows two or more Input files to be combined in a single run.
September 16, 2001
In the Route command code corrected to display channel depth for trapezoidal or complex cross-sections
September 5, 2001
Pond command modified to estimate time to centroid if last ordinate in outflow hydrograph is finite.
In Channel command code corrected to allow extra point to be added in table of coordinates.
July 12, 2001
In Catchment command rainfall loss parameters in SCS method made more interactive so that change in one causes related parameters to be updated.
June 22, 2001
Time of Concentration tool modified to allow choice between Friend eq. And Kinematic Wave eq. for overland flow time. Tool can be used for both Metric and U.S.Customary units.
June 17, 2001
New tool added to Pond command to allow user to compute equivalent aspect ratio for an irregular base area with known area and perimeter based on the equation 4R + 4/R - 8 = P^2/A.
Mar. 14, 2001
The Miduss Help file was updated to show the Microsoft2000 WinHelp format with an Explorer type navigation tree in the left panel.  This requires the addition of the file RoboEx32.dll.  This was omitted in the March 12 versions of the Setup file and the compressed Help file M98Help.exe
Mar. 12, 2001
New Time of Concentration tool added.  Also new tool to define storms for Malaysian users.  Accessible only to users with Malaysia pack.
In the Graph command an error in drawing arrows has been corrected.
In the Pipe command the design result shows an improved graphic of the normal flow and critical flow depths.
A {First time User?] button has been added to the Disclaimer form to help first-time users to get help.  The Help system has been re-compiled using the Windows 2000 WinHelp style and Chapter 1 of the Help file has been improved.
Code has been modified to detect Windows ME and 2000 operating systems in order to locate Notepad, Wordpad and Calculator more easily.
Jan. 23, 2001
The Setup program has been modified so that for Windows NT v 4.0 and Windows 2000 the secondary setup procedure to create an NT Service is now done automatically.   Previously this required execution of the file CrypkeyService.exe.
The paths used to execute applications such as Calc, Notepad and Wordpad have now been customized to suit standard installation of Windows NT 4.0 and Windows 2000 as well as Windows 95, 98 and ME.
Jan. 9, 2001
In the channel command the water level and critical depth level were not plotted properly if the cross section was divided into two or more channels - e.g. a road cross section with water level below crown elevation. This has now been corrected.
Dec. 16, 2000
When using the Hydrograph/Undo command in Automatic mode to correct or remove a Combine command the warning message persisted due to cycling.  This has been corrected.
A related error which occurred when updating the list of Junction nodes in the Combine command has also been corrected.
In the Trench command numerical instability was sometimes encountered if the lowest invert level of the outflow control was significantly higher than the upper limit of the storage element in the trench.  This was due to the fact that the slope dStorage/dDischarge was either zero, infinity or a singular point.  This has been corrected by adding an optioin to allow the user to define the diameter of the access riser (i.e. manhole acess) to be defined in such cases.
In the Pond and Trench commands the orifice discharge sometimes displayed very small negative values when the head was close to zero.  This has been corrected.
The Authorization Information window and the Disclaimer window now display the date of the current executable.
The CDrypKey licenses have been upgraded to version 5.5 in order to be fully compatible with the Microsoft Windows ME operating system (when supplied by an OEM).   Both the Setup program and the compressed update file 'm98v100FS.EXE ' now install new libraries automatically.
Note that new KeyCodes for CrypKey version 5.5 are generally different from those used for version 4.3 of CrypKey.
In the Storm command use of the Chicago hyetograph timestep multiplier now disables the [ACCEPT] button to force the user to use the [Display] button to update the results.
In the Pond/Rooftop storage command the number of roofdrains is displayed prior to acceptance of the design.
Nov. 30, 2000
Both Setup.exe and m98v100FS.EXE now have updated Crypkey libraries which eliminate problems when installing on a computer which has an OEM installed version of Windows ME.  
In the Pond command, use of the Rooftop Storage option now displayed the number of roof drains corresponding to the user specified density in sq.ft/drain or sq.m/drain.  
In the Storm command the Chicago option offers the user an option to define a multiplier for the time step.  Previously if this was used the [ACCEPT] button was not disabled (i.e. grayed out) to force use of the [Display] button.  This has now been corrected.
Nov. 15, 2000
Remake of Setup, m98v100 and m98v100FS files to correct a problem which occured on certain computers depending on the version of certain Microsoft DLL files.
N.B.  If you downloaded any of the Nov. 5 files you should replace it with the Nov. 15 version to be on the safe side.
Nov. 5, 2000
In the Show/Graph command the Edit/Draw/Arrow command has been corrected so that arrows are drawn from the starting click to the finish click.
In the Setup.exe file a file FSclient.ini has been added.  This causes a diagnostic file Error.log to be created if a run-tiime error is encountered and, if you are currently connected to the internet, the file is automatically sent to to report the problem and help us to provide the necessary fix.
Nov. 1, 2000
In the Trench and Pond design commands an obscure error occurred in automatic mode if zero values were read in to the H-Q-V grid by using the [RUN] or [STEP] command in the Control Panel.  This error has been corrected.
Oct. 21, 2000
If the Trench and Pond Design commands were used in automatic mode and the input file had been edited to change one or more of the design parameters (e.g. the Trench grade) the stage discharge curve was not always properly updated unless the [Compute] button was pressed.  The update to both outflow and storage curves is now done automatically.
Sept. 9, 2000
In the Show/Graph command the lower margin contains the name, date and time of the output file to assist in cross-referencing plots and runs.  An error in the positioning of this string has been corrected.
July 14, 2000
If Pipe design detects a surcharge condition and user wishes to modify design, the warning message now shows the lower limits for diameter or grade.
In the Pipe Design command the depth as a fraction of the diameter is now also shown beside the depth of uniform flow.  This may help users who like to design for pipes running 2/3 to 3/4 full.
June 6, 2000
In the Route command the [Undo] button is now disabled in Automatic mode in case you press it by mistake instead of the [Accept] button. Also the format of the Output file has been improved. When using Route in Automatic mode and either the Inflow hydrograph or the conduit has not been properly defined the current record pointer in the input database has been corrected to prevent cycling.
When you are prompted to select the units the text in the yellow textbox has been made more explicit in case the menu item is not properly displayed.
When using the Edit Panel in Automatic mode the drop down list used to display a subset of the commands in the database has been corrected.
When using the 'Quit and Start Over' menu item all hyetograph and hydrographs are now set to zero thus correcting a previous error.
May 22, 2000
The Setup program now installs the FailSafe (TM Compuware Numega) version. Although 1 MB larger, the executable is not noticeably slower and has proved popular with both new and experienced users.
In the Qpeaks summary table the reach length has been added to the 'Pipe Route' and 'Channel Route' labels to assist users with long runs in Automatic mode.
In the Channel command the plot of the cross-section has been improved to distinguish between the water surface and critical depth levels.
In the FileI/O command read or writing of a hydrograph file causes the peak flow and total volume to be recorded in the current output file. When a hydrograph file is read in both peak flow and volume are updated for the particular hydrograph which is overwritten and these values show properly if the Show|Table|Hydrograph is used.
March 30, 2000
In the Hydrograph|Combine command the [New] button is not disabled in Automatic mode. This allows you to use Combine in Manual more while the Control Panel is still visible.
In the Catchment command code has been corrected to allow you to set the runoff coefficient to 1.0.
March 4, 2000
In the Trench command a minor correction has been made to show whether a weir or Orifice is being defined when using the Outflow Control option.
In the Catchment command a correction has been made to allow a Runoff Coefficient of 1.0 to be defined.
Feb. 10, 2000
If the Plot command is used in either the Pond or Trench design options pressing the primary mouse button whili moving the cursors causes the values of Level, Discharge and Volume to be displayed in the title bar of the Plot window. This does not alter the functionality of the command and is merely for convenience of the user in interrogating the plot.
Dec. 23,1999  
After the units and an output file have been defined new users were presented with the main menu but with no suggestion as to the next step. A prompt message has been added to describe the various options available.
Nov. 19,1999  
In the Channel command the output file displayed the maximum depth incorrectly when defining a complex channel cross-section. This has been corrected.
In Automatic mode a channel with a complex cross-section is now displayed with improved scale factors.
Both the Channel and Pipe commands can be used without having to generate an Inflow hydrograph. If this occurs in Automatic mode the message "No Inflow - cannot continue" was displayed. This has been corrected to allow the user to abandon the command or continue to use it with the previous or other user specified flow.
Nov. 9, 1999
If the user closes the Storm Descriptor window without Accepting it a message was displayed when subsequent menu items (e.g. Hydrology) were attempted. This has been improved by displaying the Storm Descriptor window after pressing the [OK] button on the massage box.
If the Hydrology|Lag and Route command was used after the Hydrology|Baseflow command was used on a previous tributary the first 1 or 2 elements of the routed Overland flow hydrograph contained small but finite values which should have been zero or close to zero. This has now been corrected.
Nov. 3, 1999
Users trying to use the Design|Diversion command without having previously defined either a Pipe or Channel experienced a run-time error (division by zero). This has now been corrected so that the Diversion command can be used to simply split an Inflow hydrograph into two components.
Oct. 20, 1999
A network version of MIDUSS has been developed but has not yet been tested on other than small, peer-to-peer networks. A special SetupClient program has been developed to allow the necessary control files to be downloaded from the server to a Miduss Client computer. This is not yet available from the web site.
Oct. 1, 1999
The spin=button added to the Channel window (Aug.15, 1999) has been removed until some problems have been resolved.  Reduction of the number of decimal places caused loss of accuracy in the cross-section coordinates (Sorry!)
A new version of the main executable 'Miduss98.exe' has been made available as the compressed, self expanding file 'm98v100FS.EXE'.  This version has enhanced error trapping and writes trace and diagnostic messages to an Error.log file in the \Miduss98\ folder.  See News item elsewhere.
In the Pond command the program failed to trap a value of more than 50 levels and crashed. This is now fixed.
When running in Automatic mode using the [STEP] button, the time parameters were read in OK but the maximum hyetograph and hydrograph arrays were not defined properly. Then if the Hydrograph|FileIO command was used to read in and define the storm (instead of using the Storm command) an error occurred. This has now been corrected.
Sept. 22,1999
In the Catchment command if the option is chosen for user-specified flow lengths on the pervious and impervious fractions, the impervious flow length was someetimes improperly defined in Automatic mode. This is now fixed.
Sept. 16,1999
In the Help|Tutorials command an error has been corrected which prevented Read-only files (e.g. on the CD) from being accessed.
In using the FileI_O command to import a flow hydrograph an error has been corrected which prevented the Hydrograph|Undo command from restoring the original hydrograph file.
In the Channel command the critical depth is shown in the cross-section plot as well as the uniform flow depth. In the table of coordinates a horizontal scroll bar has been added. If more than 10 points are being defined graphically the grid table scrolls right automatically to show the coordinates of the current point.
In the Hydrograph|FileI_O command an error is corrected which prevented a new file name from being entered if a previous file of the same name was found and would be overwritten.
In the Tools|Add Comment command the prompting text "Enter text here..." is not shown in Automatic mode because the text box does not have the focus and therefore required the user to delete it or overwrite it.
If more than 21 lines of comment are entered vertical scroll bars are enabled and the height of the Comment window is limited to the height of the MIDUSS window.
In the Channel command the form can now be resized to show more than 10 columns of coordinate data if required.
Also in the Channel command, the number of decimals used in the coordinate grid can be increased or decreased by clicking on a spin button.
One common use of the Diversion command in Automatic mode is to subject a drainage system designed for (say) a 5-year storm to a more severe rainfall (100-year). When a pipe is found to be surcharged MIDUSS suggests that the user may want to use the Diversion command to separate the major and minor flow components.
When running in Automatic mode MIDUSS 'peeks' ahead of the Pipe command to see whether or not a Diversion command is already present. If it is, the prompt is skipped.
When the Diversion window is opened, the default value of the Node number is set to either the last Catchment number or, if the Confluence command was used prior to the Pipe design, the number of the junction node is used. The default Description is set as "Major flow at node 123" where '123' represents the default node number.
MIDUSS detects whether the Diversion command is called from the Main Menu or from the Input database file. In the latter case, the default values of Node number and Description are read from the input file.
After using the Diversion command MIDUSS suggests that the Hydrograph|Next Link command should be used. If you respond [Yes] to this prompt, this is done automatically.
When the [Accept] button is pressed in the Diversion form the program checks to see if the diverted flow file already exists. If it does, a warning is displayed to change the Node number. An error which prevented a change from being made is now corrected. If the Node number is changed the description is automatically updated.
July 14,1999
When trying to transfer a license to a computer which already has a valid license the message advising that the old license must be 'killed' was unclear.   This has been improved.
When using the Hydrograph|Undo command to reverse a Hydrograph|Confluence command, junction file is re-constructed.  An error in the formatting of the restored file has been corrected.
In Automatic mode if a previously designed pipe is found to be surcharged a warning message asks if this is acceptable.  The default button is now [No].
In the Tools|Add Comment window a vertical scroll bar has been added for very long comments (you always add comments, of course!).  In Automatic mode the height of the Comment window is limited to the screen height less one line.
In Automatic mode the Storm command did not respond to the first Tab click to change the storm type.  This is now corrected.
May 6,1999
In the Channel command using a complex cross-ssection with  the user-specified peak flow option an error occurred if Q was left at zero.  This is now trapped.
The Setup.EXE program has been improved to make the installation of an NT Service automatic instead of requiring special action by the user.
In the Show|Graph command showing multiple hydrographs sometimes caused a scaling error depending on usage.  This is now corrected.
If the Storm command is used more than once the program now 'remembers' the previous Storm option.
Using the Hydrology|Lag & Route command caused the Inflow hydrograph to be unaccessible to other options such as Show|Quick Graph.  This is now corrected.
Some errors associated with the File|Quit & Start Over command have been corrected.
In the Trench command, setting the ground water elevation equal to the trench downstream invert level previously caused a 'division by zero' error.   This has been corrected.
When using the [RUN] or [STEP] buttons on the Control Panel to process the Storm command in automatic mode, the storm descriptor (e.g. '005hyd') was previously not written to the output file.  Using the [EDIT] button was OK.  Now all three buttons cause the descriptor to be copied properly.
In the Trench command the check box to include the base width in the exfiltration area is now shown explicitly and the default condition is 'checked'.  An extra record is written to the output file to record the state of the checkbox.  The program works correctly with both old and new file formats.
In the Trench command the default number of stages has been increased from 21 to 41 (i.e. 40 depth increments).
When running the Trench command in automatic mode with the [EDIT] button the [Accept] button was not always enabled.  This is now corrected.
In the Catchment command the [Show Details] button sometimes showed incorrect values for the runoff depth and rainfall losses.  This is now corrected.
In the Trench command the range of depths is now calculated from the downstream invert to the top of the trench at the upstream end.  Previously the trench height was used.
In the Catchment command the default value of initial abstraction (Ia) is now computed to be consistent with the default curve number CN when the SCS option is used.   Both pervious and impervious fractions are corrected.
In the Trench command the [Accept] button is disabled when any change in data is made.  This forces the user to repeat the [Route] command.
When running in Automatic mode, attempting to import a storm file (e.g. 5year.stm) caused the file extension to be changed to 'hyd' which required manual editing of the filename.  This error has now been corrected.
When a storm event is defined by means of the Hydrograph|FileI_O command instead of by the Hydrology|Storm command the correct total depth was not written to the output file.  Also, the StormDescription window was not displayed.  These errors have now been corrected.
In the Hydrology|Catchment command, if no runoff (effective rainfall) resulted from the pervious fraction the time of concentratioin in the [Show Details] display was shown as 999999.000.  This has been changed to '---'.  Also some error diagnostics and messages have been corrected. 
Mar. 6, 1999
When using the File|Output|Create New file or Open Existing file and there is already an existing file of the same name the Message box now offers three choices to (1) overwrite the file (2) go back and define another filename or (3) abort the operation.
Some diagnostic printout in the Storm command was included by accident in the March 3 version.   This could have affected running in Automatic mode. This has now been removed.
Mar. 3, 1999
In the Automatic/Create Miduss.Mdb command (or the File/Open Input file command) the Open File dialog box starts at the currently defined Output file folder.   In the same command, if the selected file does not have an Exit command as the last command, an extra pair of records are added to provide an Exit command.  This fixes a problem if an input database without an Exit record was run to the End-of-File.
Feb. 9, 1999
The Diversion command has been fixed so that in Automatic mode, a change of the threshhold flow is correctly read from the input database.  Previously it was reset to the capacity of the last pipe.
Jan. 26, 1999
In the Pond command code corrected so that if user defines number of levels <=8 the grid of Levels - Discharge - Volumes displays the bottom row correctly and avoids 'Illegal row' error. 

In Pond, when the Geometry|Rectangular pond command is used with a very large depth (e.g. by setting WLmax as 155 instead of 15), the base area suggested by MIDUSS is shown as zero instead of generating an illegal operation error.

The [Compute] command button on the Pond window (to the right of the grid has been removed as it caused more confusion among users than it was worth.

In the Pond menu the items Geometry|Compute Volume and Outflow Control|Compute outflow are enabled only if a storage volume device or a flow control device has been specified.

Code in the Pond commands Geometry|Graph Volume and Outflow Control|Graph Outflow has been corrected.

Code in the Pond commands to compute Storage Volume, Outflow Control discharges or Rooftop storage and outflow for less than 8 levels now works correctly.

When running in Automatic mode execution stops properly at the end of the file even if a File/Exit command is not present.

Jan. 7, 1999
In the Trench command code has been corrected to allow the number of stages to be less than the number of rows displayed in the H - Q - V grid (i.e. 8).
Jan. 4, 1999
When running some versions of the file Miduss98.exe under Windows NT4.0,  pressing the [Run MIDUSS] button on the Authorization Information window caused the program to exit with the message "License manager is closing down".   The corrupted code has been corrected.
Dec. 27, 1998
Explanatory messages displayed for commonly encountered Crypkey errors.  Crypkey is the copy protection system built into MIDUSS98.
Route command handles cases of very peaky inflow hydrographs on steep slopes (eg. >1%) which previously gave peak outflow greater than inflow due to discretization around the the peak.
In Channel command, code corrected to allow manual entry of slope.   This was a hangover from earlier attempt to allow comma as decimal separator.
In Hydrograph/Start/Edit inflow, code to show the time of the cell under the mouse pointer has been corrected to work properly when grid is scrolled down.   Also, form corrected to show down arrow in vertical scroll bar.

Command Hydrology/Lag & Route has been corrected to work properly when units are Imperial or U.S.Customary.

The Authorization Information window has been corrected to show 'Authorization OK' instead of 'NOT present'.

Generation of file 'Main.log' (log of license manager) is now enabled as default.




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