This command will allow a graph created under UTILITY/CREATE GRAPH FILE to be retrieved, viewed, and printed. The following are steps required to plot a graph using the QHM graph program:
Create Graph Data File: this may be done from the graph program under the file menu - New Graph Data File or from the QHM main menu under Utility. Creating a graph data file should be done at the end of the QHM run.
In the dialog box for creating a new graph data file, the user selects the time series IDs to be plotted. These IDs are corresponding to the IDs that were specified for different commands in the primary input file. Up to three series IDs may be plotted and one rainfall Hyetograph that appears on top of the series ID graphs. The extension of the graph data file to be created must be ".plt." The user may create as many graph data files as are needed and may view or print them at any time.
This menu will create an input file for QHM. Before using the interface, the user should have assembled information about the problem that will be addressed by the QHM simulation (see Getting Started Section above).
The user must begin by opening an input (.inp) file. If an existing file is selected, it will be overwritten.
The Input Interface cannot be used to edit an existing input file; this can be done in a text editor. Note also that once information from an Input Interface screen is written to file it cannot be corrected in this utility; corrections must be made using a text editor. (An option to use of this interface is to edit sample files provided with the program to represent the user's system.)
The Input Interface menu is organized in terms of groups of QHM commands as follows:
INITIALIZE: START, FINISH, POLLUTANT RATES
EXECUTION: GENERATE, STORE, EROSION
ROUTE: RESERVOIR, REACH
UTILITY: Utility Commands
The user is expected to invoke these commands in the order in which they will appear or reappear in the input file. The following deals briefly with individual commands which are discussed in detail in the user's manual.
In this screen, the user first enters the limits of the time period to be simulated and the name and format of data files that will be used for precipitation, flow (if an external flow is to be added or for calibration) or temperature. A precipitation file is required unless the simulation involves only routing of a specified flow series. If Evaporation is selected, monthly pan evaporation values must be entered together with correction coefficients that will be applied when watershed evapotranspiration is calculated.
If POLLUTANT RATES is selected, coefficients must be entered, where applicable, for impervious and pervious surfaces and base flow. If SEDIMENT SIMULATION is selected, soil settling velocities and size factors must be provided. In either case, buildup and washoff calculation methods, coefficients, and exponents must be identified.
This command is evoked when the input file is considered to be complete; it will add a FINISH statement to the file. Subsequent modifications to the file must be carried out using a text editor.
If pollutant rates are to be simulated, information must be entered before each GENERATE command. Values entered before the first GENERATE command will be used as defaults if the POLLUTANT RATE command is not reissued prior to subsequent GENERATE commands.
The GENERATE command must be used to describe each sub-watershed in the system. When the information required by the initial screen is entered, "Go" will request additional information. When this information is provided, "Write" will update the input file.
This command will store an external flow file identified in the START command, for simulation, calibration, or plotting.
The User Interface cannot be used in the current version of QHM to include this command in an input file. It can be added, based on Section 3.7 of the user's manual and the sample file, using a text editor.
When all of the information requested in the initial screen is entered, "Go" will request further information.
Information is entered in this screen in accordance with the user's manual. If a trapezoidal channel is selected, channel characteristics will be requested. If another channel configuration is to be used, appropriate information can be provided after "Enter."
This command can be used for hydrologic routing though a straightforward lake or reservoir system. For a more complex system, or if pollutant routing is required, the POND command should be used.
Refer to the OUTPUT and UTILITY Commands below and the user's manual for information about UTILITY commands in this menu. These sections also describe several other UTILITY commands that are not included in this menu; they can be added to an input file using a text editor.
The QHM program is structured as a series of separate commands. These can be invoked as necessary, in any order after the START command, to simulate a particular physical system. The following paragraphs provide a brief overview of these commands and describe the required format for command lines and input data. Chapter 3 of the user's manual provides detailed information about each of these QHM commands.
QHM commands can be grouped into these three categories.
Control function commands
Hydrologic simulation commands
Output and Utility commands
QHM Control Function Commands
These commands (START, FINISH) allow the user to control the simulation run (i.e., initialize the run and terminate it respectively). The START command also allows the user to elect to simulate one, both, or neither of the pollutant types in the model.
These commands also define the type of algorithm that the model will use for pollutant simulation and provide parameters necessary for these algorithms. Subject to certain restrictions noted below, the START command can be issued repeatedly through a run as required to modify generation methods, parameters, or simulation spans.
QHM Hydrologic Simulation Commands
These are the actual functional commands of the model and represent the entire repertory of simulation capability. The commands allow the user to carry out the following operations:
Generate a synthetic time series of stormwater runoff from a watershed (GENERATE).
The user may route a time series through a channel or river reach (REACH) and/or a detention-type control device (POND or RESERVOIR).
Time series can be added (ADD SERIES) or split (SPLIT SERIES). Although most applications of QHM are likely to be in dendritic systems, the flow split is incorporated to allow the user to simulate special system configurations, i.e., a number of control ponds in parallel.
The user may assess instream erosion potential at any arbitrary cross section using one of the three shear stress related indices (EROSION INDEX). These indices are based on excess boundary shear stress as defined by instantaneous shear stress minus critical shear stress at up to twelve arbitrary points along the channel perimeter.
QHM Output and Utility Commands
These commands include:
CALIBRATE which compares simulated and recorded flow series.
SERIES STATS, EXCEEDANCE CURVES, SCAN SERIES and MAX/MIN which will produce statistics about flow and pollutant series.
PRINT SERIES, DUMP PRINT, and PRINT SPAN which will print output as on ASCII file or in a tabular format.
DUMP PLOT and PLOT SPAN which can be used as alternatives to the PRINT GRAPH command in the Main Menu to plot all or part of a flow or water quality series.
QHM INPUT DATA
QHM Data Formats
Format of Command Lines
All of the QHM commands are formatted in the following manner:
COMMAND NAME ((text) (parameter)) ((text) (parameter))...
COMMAND NAME is the exact string of characters representing the command to be invoked (see RUN section above) beginning in column 1 of the record and extending to column 20.
The (text) is arbitrary and may be omitted. It allows the user to annotate the file to identify variables.
Each (parameter) must be provided according to the requirements of the command. All required parameters must be provided, in the correct order but parameters are otherwise in free format. The program will only read the number of parameters it needs for any command; extra values at the end of the command group will be ignored.
The ((text)(parameter)) list must occupy only columns 21 to 79 of any record but may occur on as many lines following the COMMAND NAME as necessary.
The sequence of commands is entirely up to the user except that the first command must always be a START, and the last command must always be a FINISH.
Any line beginning with an asterisk is treated as a comment and is not interpreted by the model. A comment line cannot occur within a command line series. It must occur between command lines. Any non-comment line with an asterisk in column 80 causes a page feed to be generated after the line is read but before it is echoed.
Format of Rainfall Lines
The model reads rainfall data files in either Atmospheric Environment Service (AES) condensed format for microcomputers or HEC "STORM" model (Rosener et al., 1976) format as described below:
A) AES Format:
Eight leading blank or character spaces followed by three two-byte ASCII integer values (year, month, day), and three blank or character spaces followed by either (1) 24 four-byte ASCII values of hourly rainfall volumes in tenths of millimeters - Format: (8X,3I2,3X,24I4) or (2) 96 four-byte ASCII values of 15-minute rainfall volumes in tenths of millimeters.
B) HEC "STORM" Format:
Two leading blank or character spaces followed by three two-byte ASCII integer values (year, month, day), followed by 24 three-byte ASCII values of hourly rainfall volumes in millimeters. Format: (2X,3I2,24I3)
Rainfall data must be supplied if the GENERATE command is used but is otherwise not required. Rainfall lines must be supplied for days where rain occurs but may be supplied for all days during a simulation span including dry days. Note that the time step (DTINC) in the GENERATE Command must be equal to or less than the precipitation time step.
As noted below, the file number for rainfall data to be used in the simulation is specified in the START command (typically described as device 9). GENERATE commands only read rainfall data specified in the most recent START command. The reissue of a START command during a run therefore allows the user to change rainfall records applied in the simulation.
Format of Temperature Lines
The model reads temperature data, one line of 113 characters per day, based on either AES condensed format for microcomputers or HEC "STORM" format.
A) AES Format:
Eight leading blank or character spaces followed by three two-byte ASCII integer values (year, month, day), and three blank or character spaces followed by 24 four-byte ASCII values describing hourly temperature in tenths of a degree Celsius. Format: (8X,3I2,3X,24I4)
B) HEC "STORM" Format:
Two leading blank or character spaces, followed by three two-byte ASCII integer values (year, month, day), and twenty-four three-byte ASCII values describing temperature in degrees Celsius. Format: (2X,3I2,24I3)
The GENERATE command looks for the temperature data on device 8. Hourly temperature must be supplied if snowmelt is requested. Otherwise temperature data may be omitted.
To save file space, temperature data is only read from November 1st to May 31st inclusive. The temperature file must correspond to this interval with no records occurring in the interval from June 1st to October 31st inclusive.
Format of Flow Lines
The user is provided with the option of reading hourly- or daily-formatted WSC daily or HEC flow records when the STORE command is invoked. This section provides summary information on the data used by the STORE command. Details of this operation are presented in the description of the STORE command provided in the manual.
A) USGS Flow Records
USGS daily streamflow values, in CFS, are listed by days of the month for each year, i.e., 31 records per year. Information is provided in the following order: station number, blank, year, blank, day of month, and flow. Format: (I8,1X,14,1X,12,12F8.x)
The number of decimal places for the streamflow values is variable depending on the magnitude of the streamflow. The field is always eight columns wide. The value is given to two decimal places for flow less than 1 CFS, one decimal place for flow of 1 CFS or greater but less than 10 CFS, and no decimal places for flow of 10 CFS or greater. There is a decimal point only if there are decimal places. The field for a nonexistent day, for example, November 31 or September 31, is blank.
B) WSC Hourly Flow Records
A sequence of four flow lines (lines) is expected per day of data input. Each of the four lines contains six hours of flow data as follows:
Eight leading blank or character spaces followed by three two-byte ASCII integer values (year, month, day), and two blank or character spaces followed by six ten-byte ASCII values of hourly flow rates in cubic feet per second or cubic meters per second. Format: (8A1,3I2,2X,6F10.3)
C) WSC Daily Flow Records
A sequence of three flow lines is expected per month of record. The format is consistent with WSC records as described below:
line 1: Nine leading blank or character spaces followed by two two-byte ASCII integer values (year and month) and a blank or character space and ten five-byte ASCII values separated by a space or character value describing flow rate in either cubic feet or cubic meters per second, then four blank or character spaces and one two-byte ASCII integer value for the number of days per month (NDYMO). Format: (9X,2I2,1X,10(I5,1X),4X,I2)
line 2: The format is as described above except that the last variable, number of days per month (NDYMO), is excluded. Format: (9X,2I2,1X,10(I5,1X))
line 3: The format is as specified for line 2 except that eleven flow values are read rather than ten if NDYMO=31. Otherwise line 2 is repeated. Format: (9X,2I2,1X,11(I5,1X))
Flow data must be supplied if the STORE command is used but is otherwise not required. Flow lines must be supplied for all days during the time span indicated by the user on the STORE command.
As noted below, the FORTRAN file number for flow data to be input is specified in the START command (typically assign to device 10). The STORE commands only read flow data specified in the most recently preceding START command. The reissue of a START command during a run therefore allows the user to change flow records stored by the model.