Return Flow Calculation

Accounting : Account Reference : Diversion Account : 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

Links: No

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

Links: No

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

Links: No

Efficiency

Type: Series Slot

Units: Fraction

Description: The computed efficiency.

I/O: Output only

Links: N/A

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

Links: N/A

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: 11/11/2019