Emulating Macquarie Marshes hydrodynamics using river basin simulation based on network flow programming

This study investigated the potential to simulate a river basin with significant wetland hydrodynamics within a network flow programming (NFP) framework. The Macquarie River Catchment, which encompasses the Macquarie Marshes, was selected as a case study to test the approach. The Marshes support water-dependent ecological communities which require flooding events, triggered through natural and environmental flows, to inundate wetland areas for ecologically sufficient periods of time. Ecological responses of the Macquarie Marshes with respect to inundation are currently simulated using the Macquarie Valley Integrated Quantity and Quality Model (IQQM). This model represents the Marshes hydraulics using a rules-based algorithm informed by detailed hydrodynamic modelling of the Marshes. However, the model does not have the potential to optimise water resource and ecological management. 

The primary objective of this study was to use NFP to emulate the Macquarie Marshes hydrodynamics in a manner consistent with the Macquarie Valley IQQM model. This paper presents and evaluates several NFP techniques to emulate the Marshes hydraulics. It was found that iterative use of NFP with side constraints almost exactly matched the emulator rules and implemented them more accurately than the IQQM model. This successful outcome will enable multi-criterion optimisation of the basin operation to deal directly with the ecological responses of water sensitive communities.