For both linking structures, Supplemental Use Request is set by the following equation:

(Maximum Supplement Request slot values are set by the Max Supplemental Request method.)

If the default linking structure is active, Supplemental Diversion is set by the following equation:

Supplemental Use Delivery is then set equal to Supplemental Diversion.

However, if the sequential linking structure is active, Supplemental Diversion is a slot on the Agg Diversion Site and therefore, is calculated there. The Agg Diversion Site then sets Supplemental Use Delivery on each Water User based on the Supplemental Diversion and the Supplemental Diversion Priority of each Water User. This is explained in more detail on the Agg Diversion Site object.

The following calculations are then performed regardless of the linking structure selected:

The Supplement Return Flow is then calculated by the method selected in the Return Flow category. For example, if the Fraction Return Flow method is selected, Supplement Return Flow is the product of Supplemental Use Delivery and the Fraction Return Flow. If the Variable Efficiency method is selected, the efficiency is recalculated based on the Total Applied Water. Return Flow and Depletion are then recalculated for the new Efficiency value. Supplement Return Flow is calculated by the following equation:

Consumption and Consumption Shortage are then computed.

Finally, compute the Total Return Flow, as follows:

When the Water User is an element of a sequential Agg Diversion Site, the Outgoing Available water is set to the computed Total Return Flow. This determines how much water is available for downstream elements.

The following equations are executed from the dispatch method (this applies to a standalone or No Structure water user). This method is not available on a sequential Agg Diversion Site, but the soil moisture methods above can be used.

If the Proportional Shortage with Soil Moisture method is selected, efficiencyTemp is set to the Minimum Efficiency.

If the Variable Efficiency with Soil Moisture method is selected, efficiencyTemp is set to the computed efficiency on the slot.

If Maximum Supplement Request is in use and valid:

Otherwise

Since some water has already been applied, compute the new infiltration limit.

If Supplemental Diversion is not specified (Input or set by a rule),

Otherwise, the specified Supplemental Diversion is used.

Compute any Supplemental Diversion that runs off due to the infiltration limit, as follows:

Compute a temporary variable representing the supplemental flow that infiltrates into the soil, as follows:

Next, compute the supplemental use delivery as follows:

If the Variable Efficiency with Soil Moisture method is selected, recompute the efficiencyTemp as the new

When the Proportional Shortage with Soil Moisture method is selected, efficiencyTemp continues to be the Minimum Efficiency.

Compute the initialSupplementReturnFlow as follows. This is the amount that would become return flow regardless of soil moisture.

Calculate consumed supplemental flow as follows:

Calculate remaining available for soil moisture as follows:

Calculate the new limits on soil moisture refill including the flow to fill the soil moisture and the new infiltration limit, as follows:

Calculate the supplemental flow that fills the soil moisture, as follows:

Determine the new Soil Moisture volume, as follows:

Calculate final Supplemental Return Flow.

If the Supplemental Runoff slot is linked to another object, it is not included in the total Return Flow:

Otherwise, the Supplemental Runoff is not linked, the Supplemental Runoff is included as part of the total Supplemental Return Flow:

Compute Consumption and Consumption Shortage, and set Consumptive Use from Supplemental.

Finally, compute the Total Return Flow, as follows:

When the Water User is an element of a sequential Agg Diversion Site, the Outgoing Available water is set to the computed Total Return Flow. This determines how much water is available for downstream elements.