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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
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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 User Guide 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