A Continuous Sharing Resource Assessment System is one in which the behaviour of a water user has as little effect as possible on other water users within that system. For detailed information about continuous sharing resource assessment, refer to the Source Scientific Reference Guide. To enable it in Source:
- Choose Edit » Resource Assessment...;
- Click + to the left of the project name (Figure 1) to reveal the project’s active scenarios; and
- Right-click the scenario for which you wish to enable resource assessment and choose Add Continuous Sharing from the contextual menu (Figure 1).
You can rename the system using the same method for simple resource assessment systems. Refer to General Resource Assessment.
System Configuration
To configure a continuous sharing system, start by selecting the owner whose share is described by this system from the Owner pop-up menu (Figure 8) and define the start of the owner’s water year. The owner may be any one of the defined owners in the physical system being modelled. The other owners are assumed to use separate allocation systems, with all calculations occurring independently.
Figure 8. Continuous sharing, Configuration
The sharing of various system losses is based on long term averages. Over time, discrepancies will emerge which must be reconciled. You can control the frequency with which reconciliations occur using the Timesteps per Reconciliation field. The default is one time-step. Shortfalls identified during a reconciliation are treated as storage losses, gains as inflows. Losses and gains are shared based on account share sizes, but ignore account priorities.
The reconciliation process also resolves situations such as when multiple resource assessment systems draw upon the same water (whether such a configuration is accidental or deliberate).
The second step is to specify the percentage shares that the owner has in each storage known to the system. You use the Owner Shares tab in the relevant storage node feature editors to accomplish this.
Next, select each storage that should participate in the continuous sharing system in the Unassigned Storages list and move it into the Assigned Storages list by clicking the button with the right arrow. Note that a storage can be removed from the Assigned Storages list by selecting the storage and clicking the button with the left arrow.
As each storage is added to the Assigned Storages list, the owner’s share in that storage is added to the Total Conceptual Storage field, which is the sum of the active capacity for this owner of all of the assigned storages in the resource allocation system. You can not edit this value directly.
By default, 100% of all allocations are considered to be high priority but you can designate a lesser proportion by adjusting the High Priority Allocation field. The related fields of High Priority Storage, Medium Priority Allocation and Medium Priority Storage adjust dynamically in response.
You can adjust the Medium Priority Threshold field to determine how inflows are assigned to accounts. The field behaves as follows:
- When storage is below the stipulated threshold, inflows are only assigned to high priority accounts; and
- When storage is at or above the stipulated level, inflows are assigned to both high priority and medium priority accounts according to the percentages entered in the respective priority allocation fields.
The default Medium Priority Threshold is zero, which means that inflows will be assigned to both high priority and medium priority accounts.
The System Cap Balance Carryover specifies the maximum proportion of the owner’s annual resource cap that the system can carry over into the next water year.
Finally, you can define the loss characteristics of each storage in millimetres per day between one or more start- and end-date pairs within the water year. You can also import loss characteristics from a .CSV file formatted as shown in Table 1.
Table 1. Continuous Sharing (Storage loss rate, data file format)
Row | Column (comma-separated) | ||
|---|---|---|---|
1 | 2 | 3 | |
1 | Loss Rate (mm/d) | Start Date | End Date |
2..n | flux | start | end |
Where: flux is the loss in millimetres per day for the recurrent period defined by start through end
start is the first day of each year represented as dd-mmm (eg "01-Jan") on which flux begins
end is the last day of each year represented as dd-mmm (eg "01-Jan") when flux ends.
Adding Accounts
To add accounts to a continuous sharing resource assessment system, switch to the Accounts tab (Figure 9) and click Add Accounts to open the Add Accounts dialog (Figure 9). The nodes which appear in the list on the left hand side of Figure 8 are Water User nodes, otherwise known collectively as demand nodes. Select one of the nodes in this list and click OK.
Figure 9. Continuous sharing, Accounts
Figure 10. Continuous sharing (Add accounts)
To add accounts for more than one demand node to a resource assessment system, repeat the process of clicking Add Accounts, selecting the relevant demand node, and clicking OK.
By default, an account of each type (ie. a high priority and medium priority allocation account) is added for each water user, although only one account is required to have a maximum account balance greater than zero. Note that, where the High Priority Allocation is 100% (Figure 10), the medium priority account will remain unused.
You can delete an account-pair by selecting either of its members and clicking Delete Accounts.
To be added for annual accounting (3.5.0): The number of hosts available in a scenario will determine the number of accounts in an account type. Hosts in a scenario consist of water users, BL node and ED node.
To associate an account with a host in the RA Explorer, click on the individual account below the Account type. The section on the far right lists all the associated account hosts available in the scenario. [If a host has been associated with a previous account, it will not appear in the list.]. Click on the required host.
Account configuration
You can configure individual accounts by manipulating the controls shown in Figure 10. Fields that are grey can not be adjusted. They fall into three categories:
- Values that are inherited from previous steps and which are included for reference. Examples include the Name, Type and Priority fields;
- Values that are set by reference to other values. The Maximum Balance column is an example; or
- Fields that must first be enabled explicitly. For example, you must enable the relevant Spec Cap checkbox before you can specify an Annual Cap.
You can allocate shares water by shares or volume. You can specify a maximum cap for an account by enabling the Spec Cap check-box and entering a volumetric limit (ML) in the Annual Cap field. This cap will limit the annual volume diverted by the associated water user.
The share factor (Share Fact) defines the relationship between orders and the amount that must be released in response to those orders, having regard to losses and gains during transmission:
- A share factor in the range 0.0 < Share Fact < 1.0 indicates that a loss is expected to occur between the storage and supply point. The closer to zero, the greater the loss;
- A share factor of 1.0 indicates perfect transmission between the storage and supply point;
- A share factor greater than 1.0 indicates gains are expected to occur during transmission, such as inflows from a tributary;
- To account for the transmission losses and gains, the volume of water released from a storage to meet a water user’s order is calculated as the Order divided by the Share Fact; and
- Accounts with a lower share factor are allocated a larger share of the storage to account for the transmission losses they incur.
All share factors at a given priority level within a continuous sharing system are interrelated as follows:
