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Off allocation requests from water users connected via a supply point are constrained to on farm storages and , irrigation demands and maximum extraction rate at supply point. Note other demand types do not have functionality to make requests for off allocation water. Where specified, the on farm storage has an option to fill the storage to maximum storage volume with off allocation water. Each time step the on farm storage will place an additional request to bring the storage to maximum capacity. Depending on configuration settings, each time step the irrigation demand model may request off allocation water to fill rice ponds to maximum pond levels or other crops to opportunistic soil moisture targets (specified as depletions).
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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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