Evaluation of Drainage Management Software

The following sections outline the input requirements, computational methods and output options available with this software. The package was run through various tests for comparison with MTO drainage management practices provided by the MTO Drainage Management Manual (1997). A summary of out results and the requirements for using this software for MTO design, analysis or approvals is provided.

Model Capabilities:


Use in MTO Drainage Management Practices:

Summary Evaluation

Model Capabilities

What does it do?

CulvertMaster is a tool for designing and analyzing culvert systems. The program presents the culvert system in four parts and has design/analysis capabilities in each. Specifically:

Hydrology: simulating rainfall data and predicting peak flows for different return periods.

Tailwater: modeling receiving watercourse to determine tailwater elevation

Culvert Hydraulics: solving for specific hydraulic variables including culvert size, flow and headwater. The model is capable of analyzing multiple barrel sections with different shapes, sizes, materials, and inlets. Pressure and varied flow situations including backwater and drawdown curves can also be accounted for.

Roadway overtopping: assessing water surface elevation when capacity of culvert(s) is exceeded and roadway overtopping occurs. The program uses weir hydraulics to model overtopping.

How does it do it?

Data defining the culvert system is entered through a series of input tables/windows. (See Figure 1.) The data requirements are generally equivalent to what is needed to perform the calculations by hand, however some data is calculated automatically. The following methodolgies are used in the analysis;

Sample input windows (Figure 1)

Sample input window, culvert design Sample input window, culvert design 2
Sample input window, culvert component

Hydrology: Peak flow can either be input directly or calculated using the computer model. Peak flow estimates for upstream watersheds are performed using either the Rational or SCS Peak Discharge Methods. Rainfall Data can be input as IDF curve equations or tables. Alternately, the program can calculate rainfall tables based on National Weather Service Hydro-35 method.

Tailwater: Tailwater elevation can either be entered directly or can be calculated by the program assuming normal depth in the downstream channel. Channel geometry must be input by the user.

Culvert Hydraulics: Headwater is calculated using both inlet and outlet control options. The controlling headwater depth is given as the higher of inlet control or outlet control headwater. Inlet control headwater is determined using the equations set forth in Hydraulic Design Series No. 5, Hydraulic Design of Highway Culverts (1985), prepared for the U.S. Federal Highway Administration. Outlet control headwater is determined using the direct step or standard step method to solve the energy equation.

Roadway overtopping: The overtopping flow rate is calculated using the general broadcrested weir equation assuming the discharge coefficient is a function of submergence.

File Management

In CulvertMaster all files are saved as projects. Within each project multiple designs and or analyses can be performed. Reports can be generated for the entire project, or for a specific culvert crossing. Saving a project will save all the input data specific to each design/analysis, however, there is no function to save output.

This program produces and accepts proprietary rainfall data file format (.TBL) and rainfall equation files (.EQN) from other projects generated by CulvertMaster

Output Options

Summary reports including input parameters and analysis results can be printed for the entire project, or specific to each design/analysis.

The following rating curves and tables can be printed:

  • headwater elevation, tailwater elevation,
  • discharge (individual elements or total),
  • inlet control HW elevation (individual culvert),
  • outlet control HW elevation (individual culvert),
  • downstream velocity (individual culvert), and
  • downstream depth(individual culvert).

There is no function to save output.

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Experience Required

A basic knowledge of culvert hydraulics and hydrology is required to interpret results and to ensure the calculation methods used in the program are applicable to the scenario being modelled.

Navigation of the program requires basic familiarity of windows based programs.

Using the program

Installing: Instructions give just enough information to launch the setup program. The setup program is self -explanatory and takes approximately 2-3 minutes.

Learning: The program provides a "One minute tutorial" which is useful only to those unfamiliar with PC's/Windows in general. Design and analysis tutorials show the basic features of the program and provide enough information to get started. On line help is easy to use, is often context sensitive and provides detailed information on using the program and theories and equations used.

Using: The program is laid out logically and navigation is easy. Error notification is given for some, but not all bad input and is usually fairly clear. It is relatively easy to find answers to most questions using the on line help. The amount of data entry required is minimal. Run time for performing analysis is insignificant. Numerous plots, tables and reports are available to view results, however, they can not be saved separately or revised manually.

Comparison to Previous Version

There are no previous versions of CulvertMaster.

General Considerations

The following notes should be considered as appropriate when using this program on MTO projects or projects requiring approval by MTO.

  • The program always sets the headwater depth as the higher of the calculated inlet control or outlet control headwater. This is in line with the procedure described in the MTO DMM.

  • The rational coefficients and Runoff Curve Numbers given in the User's Guide are for urban areas only. Additional coefficients can be found in the MTO DMM.

  • The manual states that the program can handle hydraulic jumps, but no mention is made of the momentum method. The program appears to account for hydraulic jumps properly but does not state to the user that a jump has occurred or where it occurred.

  • The only place where the control type or regime is specified is the report form. This can only be seen by using print preview or by actually printing off the form.

  • The default Manning (n) values for materials do not conform to values used in the DMM. Appropriate values should be input by the user or the material.ini file can be edited to change the default values.

  • If flow rises above the top of the user-defined channel, the program assumes that there are vertical walls at the horizontal limits with the same roughness as the channel.

  • Rainfall intensity values for times of concentration that do not exactly match a duration from the rainfall table are interpolated linearly between durations/times of concentrations given in table.

  • Inlet control Headwater elevation is computed using the actual equations that the nomographs in the DMM are based on and therefore include a slope correction element. Nomographs in the DMM are assuming a slope of 0.02 m/m.

  • A limited list of culvert sizes and materials are provided with the model. A more comprehensive list has been prepared for MTO use. To obtain this list go to the material.ini web page to download this file. Make sure to save this file to the CulvertMaster directory on your computer.

  • Alternately additional culvert or inlet sizes or materials can be added by editing the file MATERIAL.INI (found in the same folder as the CVM directory) with a text editor. Instructions on how to add items are located within the file itself. This method is not very intuitive, and prone to error by incorrectly inputting data.

  • This model conducts all calculations in imperical units regardless of the unit type selected by the user. If the user selects metric units the program will convert all variables to imperical and convert the results back to metric after the analysis is complete. There is a small conversion error associated with this process, however it is insignificant.

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Use in MTO Drainage Management Practice

Minimum Requirements for Inclusion in Report

This section provides some guidance to designers, analyst and reviewers on the type of information and minimum requirements for reporting the results of a CulvertMaster analysis. This by no means should be considered a comprehensive list of the information included in a drainage report.

Summary of input parameters

A summary of input parameters needs to be provided. Most of this information is included in the Designer/Analyzer Report generated by the program. A report should be included for each location considered.

A summary of which computational methods were used for rainfall simulation and peakflow estimation should be included as well as the source of oefficients. Any variance from accepted practise should be explained.

Tabular and Graphical Output

The report should include both tabular and graphical output showing the headwater vs flow rate as minimum for each culvert analyzed. Any other variables pertinent to the reports recommendations should also be supported by tabular and graphical output. (ie outlet velocities for erosion conerns, tailwater depth)

Customized Files

The culvert sizes used by the program for calculations are standard imperial sizes even when metric units have been chosen. For example a 2400mm X 1200mm box culvert would be analyzed as a 8'X 4'. The material.ini file must be customized to provide standard metric sizes.

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Summary Evaluation

Go to the HTML version of the Summary Evaluation of CuvertMaster, or download the PDF version (249 KB)

To view PDF files, you will require Adobe Acrobat Reader.

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IDF curve:

Intensity-Duration-Frequency curves (or tables) provide the rainfall intensities corresponding to specified durations and frequencies of occurrence of rainfall events.

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