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Source functionality allows environmental flow rules to be implemented at individual points within the system and can be configured to reflect the interconnected, spatially and temporally diverse nature of ecological system requirements and the overall impact of environmental water holders on the rest of the system. This provides an explicitly defined, reliable environmental water management model in Source that can be easily related to the rest of the framework. The functionality can be used to fully realise a fit for purpose integrated modelling framework for water resources planning and management that enables the representation of planning, use and accounting of environmental water, and that can be used to carry out an analysis of alternative policy scenarios for water allocation and use. The implementation of tools to configure generalised rules is a better option than individual users configuring large numbers of custom functions (which is another option), for ease of use, management and transparency.
The majority of environmental flow sharing rules that currently exist in major jurisdictional basin plans can be represented with the core functionality. The remainder will be able to be configured using custom functions. The new functionality will address management of environmental entitlements across a range of sites and for different purposes using the proposed Environmental Flow Manager.
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Table 1. Commonwealth Environmental Water Holder Framework for determining environmental watering actions 2009
| Extreme dry | Dry | Median | Wet | |
|---|---|---|---|---|
| Ecological watering objectives | Avoid damage to key environmental assets | Ensure ecological capacity for recovery | Maintain ecological health and resilience | Improve and extend healthy and resilient aquatic ecosystems |
Management objectives |
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| Management actions |
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| Key goal | Damage avoidance | Capacity for recovery | Maintained health and resilience | Improved health and resilience |
Environmental flows are represented and managed in Source using two main mechanisms, the Environmental Flow Node (EFN) and the Environmental Flow Manager (EFM).
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The flowchart in Figure 1 depicts the overall process of eFlow management (Figure 2). The water available to the EFM (i.e. water available in account portfolios managed by the EFM) is calculated in the resource assessment and passed to the EFM. Water to be set aside in a reserve for later use or carryover (as specified by the user) is subtracted from the available water. The EFM manages all actions specified at EFNs that have been assigned to the manager. The EFM ranks the actions in priority order based on condition and an importance weighting specified for each action. The EFM then determines which actions are to be activated based on the cost (water requirement) of the action and the water available in accounts (see Figure 3, for more details). The Environmental Flow Nodes generate demands for actions activated by the EFM (see more detail in Figure 4). During the ordering phase, the EFN places orders for the eFlow demands, which are delivered during the flow phase. Subsequently, accounting for environmental flows is done through the EFM. The EFN assesses if actions have been successful and keep track of time since last success, and condition. More details on the calculations and user specifications for each step in the process are provided in Table 1.
Figure 1. eFlow management process
Principal developer
Murray Darling Basin Authority and eWater, with assistance from
- Office of Environment and Heritage, NSW,
- Commonwealth Environmental Water Holder,
- Department of Environment, Land, Water and Planning, Victoria,
- Melbourne Water
- Department of Primary Industry, NSW
- Victorian Environmental Water Holder
- Department of Environment, Water and Natural Resources, SA