Document History
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Each OAN processes the orders for its direct users downstream (including the next downstream OAN) and passes the combined orders up to the next OAN (if there is one). This means that it is possible to share off allocation water between multiple downstream reaches.
In the example illustrated in Figure 6, below, OAN3 has a share component in OAN2 which also has a share component in OAN1. This means that the off-allocation requirements of water user 3 and 4 are accumulated up the system and are reported as the off-allocation requirement of OAN2. This means that the allocation of off-allocation water to reach 1 takes into consideration the downstream requirements. It is possible to give priority access to downstream requirements by assigning the highest priority to OAN2 in the OAN1 allocation table.
Note that while OAN1 assigns a volume of off-allocation water to OAN2, the processing of OAN2 may result in a change in the volume of off-allocation water available to that reach as the rules specific to OAN2 are used to calculate the available water. 
Figure 6 — Example of multiple off allocation reaches
Off allocation and storages
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Model Element | Parameter | Frequency | Notes | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Off-allocation system | Usage: System usage | time step | For each off- allocation system configured | ||||||||
Account Type | Remaining Capacity: Difference between account type cap and account type usage | time step | For each off- allocation system account type configured | Account Type | Usage: Account type usage | time step | For each off- allocation system account type configured | Accounts | Remaining Capacity: Difference between account limit and account usage | time step | For each account in an off- allocation system account type |
Accounts | Usage: Account usage | time step | For each account in an off- allocation system account type | ||||||||
Water user/Account Holder | Allocation: No sure? | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Constrained Order: Don't know? | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Equalisation Ratio: Ratio between water user usage and total usage for the account type | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Non Debit Balance: Don't know | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Order Volume: Off allocation request volume for the current time step | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Remaining Capacity: Difference between the water user off allocation limit and the water user usage | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Total Volumetric Share: Off allocation share since the start of the water season | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Usage: Accumulated off allocation use since the start of the water year | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Usage Today: Off allocation volume used in the current time step | time step | For each account holder in an off- allocation system account type | ||||||||
Water user/Account Holder | Volumetric Share: Share of off allocation volume | time step | For each account holder in an off- allocation system account type | ||||||||
Off-allocation node | Borrow and Payback | time step | For all off allocation nodes | ||||||||
Off-allocation node | Constituents | time step | For all off allocation nodes | ||||||||
Off-allocation node | Downstream flow>Flow: Downstream flow | time step | For all off allocation nodes | ||||||||
Off-allocation node | Downstream flow volume>Volume: Downstream volume | time step | For all off allocation nodes | ||||||||
Off-allocation node | Mass balance | time step | For all off allocation nodes | ||||||||
Off-allocation node | Off allocation Flow Volume>Volume: Volume of off allocation | time step | For all off allocation nodes | ||||||||
Off-allocation node | Off Allocation Orders Volume | time step | For all off allocation nodes | ||||||||
Off-allocation node | Ordering Network | time step | For all off allocation nodes | ||||||||
Off-allocation node | Rules Based Orders | time step | For all off allocation nodes | ||||||||
Off-allocation node | Storage Volume | time step | For all off allocation nodes | ||||||||
Off-allocation node | Total Inflow Volume | time step | For all off allocation nodes | ||||||||
Off-allocation node | Total Outflow Volume | time step | For all off allocation nodes | ||||||||
Off-allocation node | Upstream flow>Flow: Upstream flow | time step | For all off allocation nodes | ||||||||
Off-allocation node | Upstream flow volume>Volume: Upstream volume | time step | For all off allocation nodes |
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