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Accounting : Account Reference : Diversion Account : Return Flow Calculation
Return Flow Calculation
The Return Flow Calculation category allows the user to specify how the return flow to the account is specified or computed. It also indicates how the account should solve based on the knowns and unknowns. In each case, the methods set the temporary variable tempReturnFlow[t]. This variable is then split and/or routed according to the method selected; see Return Flow Route or Split for details.
* Diversion Minus Depletion
This method assumes that either Diversion and Depletion or Diversion and returnFlow are known. Then, the other is solved for. See Diversion, Depletion, and returnFlow for details.
Method Details 
If Depletion is known, compute the temporary variable tempReturnFlow[t]:
    
If returnFlow[t+lag] is known, solve for tempReturnFlow[t] (this is only valid if using the Simple Lag method; if not an error will be issued). See Simple Lag.
    
If neither returnFlow[t+lag] nor Depletion[t] is known, assume that diversion will equal depletion, and compute the temporary variable tempReturnFlow[t]:
    
Then, the tempReturnFlow[t] is split and/or routed according to the selected method in the Return Flow Route or Split method.
Note:  See Return Flow Route or Split for additional information.
* Specify Return Flow
This method allows the user to input the returnFlow. This method is only valid if using the Simple Lag method; if not an error will be issued. See returnFlow and Simple Lag.
Method Details 
If returnFlow[t+lag] is known, compute the temporary variable tempReturnFlow[t]
    
If returnFlow[t+lag] is unknown, compute the temporary variable tempReturnFlow[t]
    
Then, the tempReturnFlow[t] is split and/or routed according to the selected method in the Return Flow Route or Split method.
Note:  See Return Flow Route or Split for additional information.
* Fractional Return Flow
This method allows the user to input a constant fraction of the diversion that is returned.
Slots Specific to This Method
 Fraction of Diversion
Type: Scalar Slot
Units: None
Alternate Units: NA
Description: Fraction of the Diversion that is returned
I/O: Input Only
Method Details 
This method computes the temporary variable tempReturnFlow[t]:
    
Then, the tempReturnFlow[t] is split and/or routed according to the selected method in the Return Flow Route or Split method.
Note:  See Return Flow Route or Split for additional information.
* Variable Fractional Return Flow
This method allows the user to input a series slot that contains the fraction of diversion that is returned.
Slots Specific to This Method
 Variable Fraction of Diversion
Type: Series Slot
Units: None
Alternate Units: NA
Description: Fraction of the Diversion that is returned
I/O: Input Only
Method Details 
This method computes the temporary variable tempReturnFlow[t]:
    
Then, the tempReturnFlow[t] is split and/or routed according to the selected method in the Return Flow Route or Split method.
Note:  See Return Flow Route or Split for additional information.
* Variable Efficiency Return Flow
This method allows the user to compute the return flow as a function of the specified Maximum Efficiency, Depletion Requested and Diversion.
Slots Specific to This Method
 Depletion Requested
Type: Series Slot
Units: Flow
Alternate Units: Volume
Description: Desired amount of water to be consumed by the diversion account
I/O: Input or Rules
 Efficiency
Type: Series Slot
Units: Fraction
Description: The computed efficiency.
I/O: Output only
 Maximum Efficiency
Type: Scalar Slot
Units: Fraction
Description: The maximum possible efficiency. It is also the default efficiency if there is no Depletion Requested. Must be between 0 and 1.0 inclusive. See Depletion Requested.
I/O: Required Input
Method Details 
When Depletion Requested is known, Efficiency is computed as follows. See Efficiency.
    
If Depletion Requested is not known, Efficiency is equal to the Maximum Efficiency:
    
Depletion is computed as follows. See Depletion.
    
A temporary variable tempReturnFlow[t] is computed:
    
Then, the tempReturnFlow[t] is split and/or routed according to the selected method in the Return Flow Route or Split method.
Note:  See Return Flow Route or Split for additional information.
Revised: 12/01/2020