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Ownership at nodes and links

Owned by asatheesh (Unlicensed)
Last updated: 12 Oct 2023 by TeamcityVersion comment
8 min read
This feature is not available in Source (public version).

This section describes how to configure ownership at each of the nodes and links in Source.

Ownership information is required at splitter nodes to determine the proportion of each owner’s water to be directed to each outlet (as shown in Figure 1). Ownership of unallocated flows from a splitter can be distributed according to owned amounts or by selecting different proportions to the owned amounts. The following parameters are optional:

  • High flow threshold - the threshold above which high flow losses occur; and
  • Don’t Borrow to Meet - if enabled, the model will attempt to get as close as possible to the specified proportions without borrowing water.


For the Gauge node, you must specify the sharing method (either as percentage or a unit share) and whether ownership must be reset using the Reset Ownership checkbox (Figure 2).

The Sharing Method is a volumetric entitlement for sharing water amongst owners (Figure 3) as either a proportion (by selecting Fixed Percentage) or as a function (by selecting Owner Flow Function) using the Function Editor. In the former, the proportion refers to a percentage of the total for all owners. For example, if Owner 1 is allocated 60 and Owner 2 is allocated 50, the first owner's proportion will be a percentage of the total proportions (ie.60/(60+50))%.

Note: All proportions cannot be allocated zeros at once.

Click the Ownership tab in the node’s feature editor (Figure 4) to choose the sharing method and specify the proportion for each owner. The High Flow Threshold checkbox refers to the threshold above which high flow losses occur, for which you can specify a threshold flow rate.

Specify the maximum order constraint via a function using the Function Editor. Also include the proportion for each constraint/owner sharing level (Figure 5).

If there are multiple owners, the additional orders to meet minimum flow requirement (or total shortfall) are shared according to the owners' share of the minimum flow requirement.  That is, the orders for each owner will increase by their share of the Minimum Flow Requirement - Owner's Downstream Orders (or owner's shortfall).  The minimum value an owner's shortfall can be is zero, so if their share of the Minimum Flow Requirement is less than their Downstream Orders, the total owners shortfall will be less than the total shortfall.  In this case the owner's orders will be increased by the Owner's Shortfall / the Total Owners Shortfall x Total Shortfall - a larger amount.

The owner's share can be specified as Proportional (shared equally) or Fixed (enter the proportion for each owner in the Minimum Order Sharing table of Figure 6).



Each owner’s share of water is conserved at a storage node where ownership has been enabled except when:

  • Water is ceded to other owners according to distribution rules;
  • An owner does not have sufficient storage capacity to hold their water, so it is internally spilled to other owners. This can be disabled if required using the Internal Spilling radio button. Internal spilling occurs when an owner’s volume of water in storage exceeds their current storage capacity and excess is transferred to another owner.
  • Water is borrowed or lent to other owners so that demand can be met, which can be later paid back either at the same storage, at the nominated payback storage, or handled by the resource assessment process.

An owner’s volume of water in storage is adjusted for their share of inflows, regulated releases, external and internal spills, lateral losses and gains, and flows along wetland links. Inflows may be from upstream or wetland links. Regulated release ownership is determined by each owner’s downstream order.

Using Figure 7, you can choose which owner will be assigned 100% ownership of the storage, its inflows, losses/gains and releases when ownership is suspended using the Override Owner drop-down menu. When conditions in the specified function are met, the ownership system will be suspended. You must also specify each owner’s share of the storage capacity, as well as the initial share.


Suppose one of the storage owners wants to increase its storage capacity as long there is adequate airspace in the storage and does not impact the actions of other owners. This can be achieved by enabling the 'Use Airspace' option when 'Internal Spilling' is selected as illustrated in Figure 8. In the figure, the owner 'Blue' can exceed its capacity share of 40,000 ML temporarily instead of internal spilling, when there is enough airspace in the storage. The airspace owner volume can increase when the non airspace owners ('Red' and 'Yellow') are not using full share of capacity and the airspace owner ('Blue') receives inflows. Also, its increase should not affect the storage capacity and internal spilling of the owners 'Red' and 'Yellow'. That means if Yellow reaches its capacity and still has inflows coming in, it should internally spill to Red, given Red has available airspace. If Red still has airspace available, Blue can utilize that space to increase its share, and excess water from Blue if any will spill externally.

                                          Figure 8. Internal Spilling with 'Use Airspace' option

An example model is shown in the Figure 9, in which the owners Blue and Yellow have 1000 ML/d inflows each going in to the 'Storage 1'. The Storage 1 ownership is set as in Figure 8 with Blue having the 'Use Airspace' enabled. All the owners (Red, Blue and Yellow) have a downstream minimum flow requirement of 100 ML/d each. The model run results are illustrated in Figure 10. It can be seen that from day 12 Yellow internally spills to Red and Blue externally spills the blue net inflow. Then on day 25 they all reach their full capacity share and from then on yellow only spills 100 to red to keep it topped up and the excess water is externally spilled.

Figure 9. Example model with 'Share Airspace' option enabled for one owner

Figure 10. The example model simulation run results 

Lateral losses and gains include rainfall, evaporation and groundwater infiltration. These fluxes are categorised into those that are shared in proportion to the share of water stored, or according to a fixed ratio, which can be configured (as shown in Figure 11). This window is the same for Rainfall and Evaporation, and is similar for each of the Outlet Paths. An additional parameter you must specify is the distribution system that the link falls in.


To enable ceding amongst owners, select Ceding in the hierarchical list. Click Add Cede in the right-side panel, then enter the ‘from’ and ‘to’ owners that will be involved in the ceding process, as well as a function for the volume of water to be shared (as shown in Figure 12).



The Adjustment option (Figure 13) allows the user to adjust the ownership mass balance on storage nodes post timestep. This is useful because often there are decisions that move ownership about as a result of management/policy decisions based on what happened that day, and so provides the option to adjust the End of day volume.

The adjustments are done post-flow phase, with a borrow if the adjustment would otherwise cause an owned volume to be negative.


At this node, the total upstream owner constraint volumes are transferred to downstream owners in specified proportions (as shown here). It can be configured as either a boundary or an in-system node. Refer to Transfer of ownership node for details.

The original downstream order can be split between the new upstream owners specified at the boundary TO node (owner proportion here), and supplied using water belonging to the specified upstream owners. When flow resulting from the released order reaches the upstream boundary of the ordering location’s ownership system, its ownership is split between downstream owners according to Flow proportions (Figure 2).

Ownership options at a Supply Point are illustrated in Figure 14.

The Borrow and Payback system works so that the owners' flow best matches the proportions of their orders and tracks their borrowing. Extracted volumes are restricted to the owners' flow at the supply point and their capacity to meet their downstream order. Each owners' relative shortfall is not calculated based on a proportion of the overall shortfall, but rather the individual owner's ability to meet their own orders. 

The overbank sharing method is used to determine the ownership of the water taken by the supply point when the overbank threshold has been exceeded. This can be specified as a fixed ratio or proportional. The proportional overbank sharing method will take the water in the ratio of ownership currently in the river.


The water user node represents a demand in the model, where orders are generated and passed upstream. Figure 15 shows the proportions distributed and returned that must be specified for each owner, when non-account sharing has been selected.


The intention of ownership at links is to define which owner is responsible for fluxes that occur on links. This is available for lagged flow routing and storage links.

This dialog allows you to specify what proportion of catchment inflows are allocated to each owner. Enable the Override Catchment Inflow Proportions checkbox and specify the proportion in the table below.

These fluxes are defined as a function using the Function manager. Each link’s ownership system will always match the one for the upstream connected node. You can specify what proportion of flux to allocate to each owner using the checkboxes shown in Figure 17. Once enabled, specify the proportion in the table below.