The main function of the environmental flow manager is to prioritise and activate actions based on a priority purchasing style conceptual model (Figure 3).
Actions are defined at environmental flow nodes and consist of a set of criteria (system conditions), target response, defined success, and condition function. Actions from various EFNs can be grouped and will then be assessed by the environmental flow manager as a set of actions that need to be activated together. Groups are defined at the EFM level allowing actions for multiple assets to be linked.
The EFM prioritises the actions (or groups of actions) based on the condition of the asset (1-condition) multiplied by a user defined importance weighting (i.e. (1-condition) x importance). Environmental flow nodes keep track of the condition associated with the actions. The condition is calculated by default by dividing the average desired return interval by the number of days since last success (with values limited to maximum of 1). This can be replaced by a user specified condition function. The importance weighting is calculated using a user defined function, which allows flexibility in the way the events are prioritised and coordinated.
The Environmental Flow Manager will then determine whether there is sufficient water available to meet each group's needs in priority order, decreasing the amount available to each subsequent priority as the group above reserves water. To do this, the EFM steps through the ranked action list and compares the cost of the action (ie. the volume of water required to deliver the action) to the available water in the portfolios of accounts that can be accessed by the action. If enough water is available, the EFM will commit the water required to meet the estimated cost (i.e. subtracts the volume from the water available), so that the committed water is not available for actions with lower importance. The environmental flow manager flags the action as active to the EFN. The environmental flow manager does not execute actions, it gives permission to the environmental flow node to evaluate the criteria of the flagged (committed) rule and initiate a target response (eg. place an order) when appropriate. Accounts are not debited until after a managed target response is executed.
Figure 3. Expanded Environmental Flow Manager Conceptual Model: Detailed flowchart for the 'Prioritise and activate/flag actions' box in Figure 2.
