In certain basins, water is released from a reservoir regardless of the downstream constraints or balancing. These minimum releases are not surcharge releases but are considered minimum flood control releases. They can be modeled by setting the Flood Control Minimum Release slot and the reservoir Outflow slot with a rule; see Operating Level Balancing in Surcharge ReleaseObjects and Methods for details. It is up to the user to write the rule logic of when these slots should be set and their corresponding values. These rules should execute after surcharge, but before regulation discharge; see Order of Policies for details. Then, the minimum releases will be routed downstream and the Regulation Discharge rules will include them in their empty space determination.

It is up to you to write the rule logic to set the reservoir Outflow and Flood Control Minimum Release. Figure 3.3 shows a sample rule.

In this sample rule, the current Outflow and Flood Control Minimum Release is set to the Firm Power Release when the current Outflow is less than the Firm Power Release and the Operating Level is above the Top of Conservation Pool.

Optionally, if you wish the Minimum Flood Control Release not to go through the release or turbines, you can also set the Regulated Spill or Bypass slot in the rule. You may need to select a regulated spill or bypass method on the reservoir to add these slots to the reservoir.