Irrigation River Source Factors
A global “river source volume factor” and “river source discharge factor” are available as extra parameters for increased control of river sources during irrigation.
|
Parameter Name |
Type |
Value |
|---|---|---|
|
river source volume factor |
float |
positive |
|
river source discharge factor |
float |
0 or positive |
None, one, or both can be specified. If the factor is not specified, then a Volume factor of 0.99 and a Discharge factor of 0.0 will be used.
The factors are used in the calculation of the available water (depth) of a river source:
(39.1)
where Depth is the available water depth in the river link, Cs is the source capacity, Dt is the time step length, Fv is the specified volume factor, VL is the volume of water in the link, FD is the specified volume discharge, DL is the river link discharge, and A is the cell area.
The river link discharge is the same as used when checking with the threshold discharge for switching on/off the source. It is the absolute discharge in the middle of the MIKE SHE river link, interpolated between two MIKE Hydro River H-points.
MIKE SHE prints the following message in the xxx_WM_Print.log file when the parameters are specified:
Extra-parameter specified:
river source volume factor
value = 1.500000
Extra-parameter specified:
river source discharge factor
value = 1.000000
MIKE SHE also prints the following warnings in the xxx_WM_Init_Messages.log file if one or both of the factors may result in water balance errors or numerical instabilities
WARNING: Specified value for river source volume factor is greater than 1 : 1.500000.
There is a risk of water balance errors and/or instabilities in the coupling between MIKE SHE and MIKE 11.
WARNING: Specified value for river source discharge factor is greater than 0 : 1.000000.
There is a risk of water balance errors and/or instabilities in the coupling between MIKE SHE and MIKE 11.
Note: This option is less useful now that River Sources are defined by both an Upstream and Downstream chainage. The option is maintained for backward compatibility.
