Understanding how different ecological assets respond to flow regimes is essential to the management and delivery of environmental water.   Many of our river systems have significant amounts of regulation. This places constraints on the volume of water available for the environment and its delivery.  To understand how to make best use of environmental water, methods are required that allow us to: (a) better understand how different ecological assets will respond to different flow regimes and (b) plan for the delivery of water to multiple ecological assets. River system models are complex models used to assess the likely change in water availability over space and time, and support water planning processes. To determine the flow regime that will best meet the needs of single and connected ecological assets, within the delivery constraints, optimisation methods can be used to determine the delivery of environmental water over space and time.  This paper details the methods used to support an optimisation tool, where a river system model has been simplified. The model is used to explore optimising flow deliveries for managing environmental water releases, considering the inundation of unregulated and regulated wetlands along the length of the Murrumbidgee River, with seasonal, peak flow and duration requirements.   This simplification of the hydrology has then been used in a conservation planning framework to demonstrate how different temporal allocations of environmental water can be used to achieve an agreed set of objectives for the catchment’s wetlands.