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Scenario planning
Table 5.5.2 outlines the potential environmental watering and expected water use under a range of planning scenarios. It is expected that there will be no water available for environmental flows in the Broken River and upper Broken Creek under drought and dry scenarios. It is likely under those scenarios that there will be zero to low natural flow resulting in zero allocations of entitlements.
There are two sets of watering actions: one for upper Broken Creek and another for the Broken River.
Delivering flow to upper Broken Creek is a higher priority, because upper Broken Creek tends to have no inflows
from tributaries and is mostly dependent on flows from operational deliveries. The potential watering actions for upper Broken Creek require less water than the potential watering actions for Broken River, and any environmental flows delivered to upper Broken Creek will pass through reaches 1 and 2 of the Broken River, where they will provide some environmental benefit.
In 2020–21, the highest priority in upper Broken Creek is to deliver a summer/autumn fresh (a tier 1a watering action under average and wet scenarios, and a tier 1b watering action under drought and dry scenarios), if required to maintain water quality. The fresh is likely to be able to be partially delivered under average and wet conditions with water for the environment. There is unlikely to be sufficient water available to deliver the fresh under drought or dry conditions. If water does become available under drought or dry conditions, the priority will be to deliver a summer/ autumn fresh first, then the summer/autumn low flow to maintain critical aquatic habitat. Additional environmental deliveries for low flow and freshes are not expected to be needed under wet conditions, because flow requirements will be met by natural events.
It is expected that there will not be sufficient water available to provide any potential watering actions in the Broken River: that is, no tier 1a actions are identified. If additional water becomes available under drought and dry conditions after watering actions for upper Broken Creek have been met, the priority will be to deliver year-round low flow in the Broken River to maintain critical aquatic habitat. If further water is available, it will be used to deliver summer/autumn freshes, with dry and average conditions, to maintain habitat for macrophytes and native fish.
5.5 Broken system
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