Environmental flows are represented and managed in Source using two main mechanisms, the Environmental Flow Node (EFN) and the Environmental Flow Manager (EFM).
The Environmental Flow Node is used to generate orders to meet in-stream environmental requirements at an individual asset. The desired flow patterns are defined by configuring one or more actions including start criteria, desired flow response and frequency, as well as criteria for success of the action and condition of the asset targeted by the action.
The Environmental Flow Manager will prioritise environmental flow actions defined at Environmental Flow Nodes throughout the system. The EFM will also handle management of accounts, and apportionment of water from the accounts to particular environmental events.
These two network elements interact with each other, and the rest of the network, including the Resource Assessment System, Ordering and Flow Phase to manage environmental water (Figure 1).
Figure 1. Structural model elements of eFlow management
For details of the model phases please see: Model Simulation Phases
A legacy, research focused environmental demand node 
is still present in Source for backwards compatibility purposes. For full documentation please see the relevant sections of the Source 4.1 /wiki/spaces/SD41/pages/25821913 and Scientific Reference Guide.
This is the Environmental Flows User Guide. For more detailed information on the conceptual model and computational decisions, please see the Environmental Flows Scientific Reference Guide