Read MI Table Links == <.mif/.mid_file> 50
Read Materials File == 51
Relative Resistance == [ {RELATIVE} | MATERIAL ] 51
S Channel Approach == [ PRE 2004-06-AA ] 51
Storage Above Structure Obvert == [ {CHANNEL WIDTH} | ] 51
Trim XZ Profiles == [ ON | {OFF} ] 52
XS Database == 52
[ BG | CS | NA | VG ].... ! Fixed Field Flags 60
BG Data == 60
CS Data == 60
NA Data == 61
VG Data == 61
Read MI IWL == <.mif/.mid_file> 69
Set IWL == 69
BC Database == <.csv_file> 77
BC Event Name == 77
BC Event Text == 78
EB Data == 78
Read MI BC == <.mif/.mid_file> 78
Cell Size == 9
Grid Size (N,M) == , 9
Grid Size (X,Y) == , 9
Orientation == , 9
Orientation Angle == 10
Origin == , 10
Read MI Location == <.mif/.mid_file> 10
Read TGA == <.tga_file> 18
Read TGF == <.tgf_file> 18
External Bndy == , , , 27
Read MI [ MAT | IWL | CnM | FRIC | WrF | FLC ] == 28
Read MI Code [ {} | BC ] == 28
Read MID [ CODE | MAT | IWL | CnM | FRIC | WrF | FLC ] == 28
Read MID Grid == 29
Set [ CODE | MAT | IWL | CnM | FRIC | WrF ] == 29
Write MI Domain == <.mif/.mid_file> 29
Write MI Grid == <.mif/.mid_file> 29
Allow Dangling Z Lines == [ ON | {OFF} ] 38
Default Land Z == 38
Interpolate ZC [ {} | ALL ] [ {} | LOWER ] 38
Interpolate [ ZHC | ZUVC ] [ {} | ALL ] [ {} | AFTER ] 39
Pause When Polyline Does Not Find Zpt == [ ON | {OFF} ] 39
Read MI Z Line [ {} | RIDGE or MAX | GULLY or MIN | HX ] [ {} | CC ] [ {} | THICK ] [ {} | ADD ] == 40
Read MI Zpts [ {} | ADD | MAX | MIN ] == 41
Read MID Zpts [ {} | ADD | MAX | MIN ] == 41
Set Zpt == 42
Write MI Zpts == 42
ZC == MIN(ZU,ZV) 42
Read File == 51
Stop 51
BC Database == <.csv_file> 9
BC Event Name == 9
BC Event Text == 10
Global Rainfall Area Factor == [ {1.0} | ] 10
Global Rainfall BC == 10
Global Rainfall Continuing Loss == [ {0} | ] 10
Global Rainfall Initial Loss == [ {0} | ] 10
Read MI BC == <.mif/.mid_file> 10
Read MI SA [ {} | Rainfall ] == <.mif/.mid_file> 11
Unused HX and SX Connections == [ {ERROR} | WARNING ] 11
Free Overfall == [ {ON} | ON WITHOUT WEIRS | OFF ]
(Optional)
The default “ON” option activates the free-overfall method described in Syme (1991). The method offers better stability; particularly where major wetting and drying occurs. It also allows large tidal flats to continue to drain without being cut-off at their edges. This option also activates the automatic broad-crested weir flow switch between upstream and downstream controlled flow. Use this option where weir flow occurs over levees and embankments. This option increases the computation time, typically by 10 to 30%, depending on the degree of wetting, drying and weir flow. It is only available if Manning’s n bed resistance values are used (the method can be extended to other resistance formulas on request).
The weir flow method adjusts the Manning’s n values so that the flow across a cell side equates to the broad-crested weir formula when the flow is upstream controlled. Upstream controlled flow is determined by comparison of the upstream and downstream energy levels.
Models with a significant weir flow component should be checked by viewing cells that are affected by this option. See Section Error: Reference source not found for details.
The “ON WITHOUT WEIRS” option activates the free-overfall method without the automatic weir flow switching. Mainly used for models developed prior to 1999, which is when the weir flow option became available.
The “OFF” option deactivates the free-overfall method. Used for models with little or no wetting and drying, and no upstream controlled weir flow.
Free Overfall Factor == [ {0.8} | ]
(Optional)
Sets the free-overfall factor (see Syme (1991)). It is recommended that the default value of 0.8 be used, especially if using the weir flow option. The value should be less than 1.0 and greater than 0.5.
Froude Check == [ {1} | ]
(Optional)
Sets the minimum Froude Number that upstream controlled friction flow may occur. Only applies if Supercritical is set to ON, otherwise it is not used. Improved stability may occur in steeply flowing areas if is less than 1. cannot be below zero and would normally not exceed 1.
Froude Depth Adjustment == [ {ON} | OFF ]
(Optional)
Switches on or off an additional upstream controlled friction flow check incorporated in Build 2003-01-AF (See Section 3.14.3). Set to OFF for backward compatibility for models run prior to Build 2003-01-AF that use the upstream controlled friction feature (ie. see Supercritical).
Global Weir Factor == [ {1.0} | ]
(Optional)
Factor that adjusts the broad-crested weir formula (see Section 3.14.3). Testing has shown that a value of 1.0 to 1.1 is needed to reproduce upstream controlled weir flow (Syme 2001). This factor is applied globally, although spatial variation of the factor can be specified through a GIS layer read by the geometry control file (see Read MI or Read MID with the WrF option). Note that the global value and the spatially varying value are multiplied together (ie. one does not replace the other).
Note: This command prior to Build 2001-08-AD was General Weir Factor . For input in this free-form format, models using the General Weir Factor command will stop and a message supplied. The default value of 1.2 using the General Weir Factor command is the same as 1.0 using the Global Weir Factor command. For fixed field input, the model does not stop and no warning message is given. Any fixed field input model that specifies a general weir factor (Cols 81 to 90 on Line 4) must have the factor divided by 1.2 to produce similar results for runs using Build 2001-08-AD or later.
Shallow Depth Weir Factor Cut Off Depth == [ {0} | ]
(Optional)
Sets the “Shallow Depth Weir Factor Cut Off Depth” in meters. This value typically varies from zero (preferable) to up to 0.2 for major river systems. See discussion above on how it is applied. A value less than the cell side wet/dry depth has no effect.
Shallow Depth Weir Factor Multiplier == [ {1} | ]
(Optional)
The application of the weir equation at shallow depths may cause instabilities due to extreme lowering of the Manning’s n value. An option to minimise this affect is to use the “Shallow Depth Weir Factor Multiplier”, which multiplies the adjusted Manning’s n value. The multiplier typically has a value in the range of 5 to 20. The multiplier is linearly reduced from its full value at zero depth to a value of 1 at the Shallow Depth Weir Factor Cut Off Depth. A value of 1 has no effect on the weir calculations and is that recommended.
Supercritical == [ {ON} | OFF | PRE 2002-11-AD ]
(Optional)
Sets the supercritical flow mode. If set to ON (the default), flow automatically switches into upstream controlled friction flow, allowing the supercritical flow conditions on steep slopes to be modelled. See Section 3.14.3 and Froude Check for more details.
If set to OFF, and Free Overfall is set to ON, the broad-crested weir formula applies where flow conditions are predicted to be upstream controlled. For simulations prior to Build 2002-11-AC, this flag may need to be set to OFF for backward compatibility.
Setting to PRE 2002-11-AD provides backward compatibility for simulations carried out using supercritical flow prior to Build 2002-11-AD. In Build 2002-11-AD, additional checks using the Froude Number specified by Froude Check were incorporated in addition to the downstream/upstream controlled flow check comparison. This may produce different results in some flow conditions. The ON option is to be used in preference to the PRE 2002-11-AD option.
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